Deliberate hypotension with propofol under anaesthesia for functional endoscopic sinus surgery (FESS)

  • Review
  • Intervention

Authors


Abstract

Background

Functional endoscopic sinus surgery (FESS) is a minimally invasive technique that is used to treat chronic sinusitis. Small bleeding areas can reduce operative visibility and result in destruction of surrounding structures. Deliberate hypotension (lowering the mean arterial blood pressure to between 50 and 65 mm Hg in normotensive patients) using a range of pharmacological agents during general anaesthesia reduces blood loss in many operations.

Objectives

We aimed to compare the use of the intravenous anaesthetic agent propofol versus other techniques for deliberate hypotension during FESS with regard to blood loss and operative conditions.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (1950 to April 2012), EMBASE (1980 to April 2012), LILACS (1982 to April 2012) and ISI Web of Science (1946 to April 2012). We also searched the reference lists of relevant articles and conference proceedings and contacted the authors of included trials.

Selection criteria

We sought all randomized controlled trials (RCTs) conducted to compare propofol with other techniques. Our primary outcome was total blood loss (TBL). Other outcomes included surgical field quality, operation time, mortality within 24 hour, complications and failure to reach target blood pressure.

Data collection and analysis

Two review authors independently extracted details of trial methodology and outcome data from reports of all trials considered eligible for inclusion. All analyses were made on an intention-to-treat basis where possible. When I2 was < 40% and the P value from the Chi2 test was > 0.10, we pooled data by using the fixed-effect model. Otherwise we pooled data by using the random-effects model.

Main results

We included four studies with 278 participants in the review. Deliberate hypotension with propofol did not decrease TBL (millilitres) when compared with inhalation anaesthetics in either children or adults. Propofol improved the quality of the surgical field by less than one category on a scale from 0 (no bleeding) to 5 (severe bleeding) (mean difference (MD) 0.64 better with propofol, 95% confidence interval (CI) 0.37 to 0.91 better), but no difference in operation time was reported. Failure to lower blood pressure to target was less common in the propofol group (relative risk of failure with propofol (RR) 0.24, 95% CI 0.09 to 0.66).

Authors' conclusions

Using propofol to achieve deliberate hypotension may improve the surgical field, but the effect is small. Deliberate hypotension with propofol did not decrease TBL and operation time. RCTs with good quality methodology and large sample size are required to investigate the effectiveness of deliberate hypotension with propofol for FESS.

Résumé scientifique

Hypotension délibérée avec du propofol sous anesthésie pour la chirurgie endoscopique fonctionnelle des sinus (CEFS)

Contexte

La chirurgie endoscopique fonctionnelle des sinus (CEFS) est une technique mini-invasive que l'on utilise pour traiter la sinusite chronique. De petites zones de saignement peuvent réduire la visibilité opératoire et entraîner la destruction des structures environnantes. L'hypotension délibérée (diminution de la pression artérielle moyenne entre 50 et 65 mm Hg chez les patients normotendus) en utilisant une gamme d'agents pharmacologiques pendant une anesthésie générale réduit la perte de sang dans de nombreuses opérations.

Objectifs

Nous avions pour objectif de comparer l'utilisation de l'agent anesthésique par voie intraveineuse, le propofol, à d'autres techniques pour l'hypotension délibérée durant la CEFS en ce qui concerne la perte de sang et les conditions opératoires.

Stratégie de recherche documentaire

Nous avons effectué une recherche dans le registre Cochrane des essais contrôlés (CENTRAL) (The Cochrane Library 2012, numéro 1), MEDLINE (de 1950 à avril 2012), EMBASE (de 1980 à avril 2012), LILACS (de 1982 à avril 2012) et ISI Web of Science (de 1946 à avril 2012). Nous avons également passé au crible les références bibliographiques d'articles et d'actes de conférence pertinents, et contacté les auteurs d'essais inclus.

Critères de sélection

Nous avons recherché tous les essais contrôlés randomisés (ECR) conduits dans le but de comparer le propofol à d'autres techniques. Notre critère de jugement principal était la perte de sang totale (PST). D'autres critères de jugement incluaient la qualité du champ chirurgical, la durée de l'opération, la mortalité dans les 24 heures, les complications et l'incapacité à atteindre la pression artérielle cible.

Recueil et analyse des données

Deux auteurs de la revue ont extrait indépendamment des rapports de tous les essais jugés éligibles à l'inclusion, les détails méthodologiques et les données de résultat des essais. Toutes les analyses ont été réalisées, autant que possible, en intention de traiter. Lorsque I2 était < 40 % et la valeur P du test Chi2 était > 0,10, nous avons regroupé des données au moyen d'un modèle à effet fixe. Sinon, nous avons regroupé les données à l'aide du modèle à effets aléatoires.

Résultats principaux

Nous avons inclus quatre études totalisant 278 participants dans la revue. L'hypotension délibérée avec du propofol n'a pas réduit la perte de sang totale (millilitres) comparé aux anesthésiques administrés par inhalation que ce soit chez les enfants ou chez les adultes. Le propofol a amélioré la qualité du champ chirurgical de moins d'une catégorie sur une échelle de 0 (pas de saignement) à 5 (saignement grave) (différence moyenne (DM) 0,64 meilleure avec le propofol, intervalle de confiance (IC) à 95 % 0,37 à 0,91 meilleur), mais aucune différence n'a été rapportée concernant la durée de l'opération. L'échec de la diminution de la pression artérielle jusqu'à la valeur cible était moins courant dans le groupe sous propofol (risque relatif d'échec avec le propofol (RR) 0,24, IC à 95 % 0,09 à 0,66).

Conclusions des auteurs

L'utilisation du propofol pour provoquer l'hypotension délibérée peut améliorer le champ chirurgical, mais l'effet est faible. L'hypotension délibérée avec du propofol n'a pas réduit la perte de sang totale et la durée de l'opération. Des ECR présentant une bonne qualité méthodologique et un effectif important sont nécessaires pour étudier l'efficacité de l'hypotension délibérée avec du propofol pour la CEFS.

Plain language summary

Induced hypotension with propofol under anaesthesia during endoscopic sinus surgery

Functional endoscopic sinus surgery (FESS) is a minimally invasive technique used to treat patients with chronic sinusitis (defined as inflammation of the mucous membrane in the paranasal sinuses (air cavities within the facial bones) and fluid within the sinus cavity that lasts longer than 12 weeks). The surgeon uses a small endoscope (miniature camera) in the nose to get a close-up view of the sinuses. The main problem with FESS in practice is bleeding during the operation. Blood fills up the nose or gets on the lens of the camera, obscuring the surgeon's view. If bleeding is severe, the surgeon may be forced to abandon the operation without achieving the aim. Bleeding can cause the procedure to take longer or can accidentally damage surrounding structures, including the eyes and the brain. One method for reducing bleeding under general anaesthesia is induced hypotension, which involves deliberately lowering the patient's blood pressure to below normal. Lowering the mean arterial blood pressure in patients with normal blood pressure aims to improve the surgical field and limit blood loss. However, lowering the blood pressure carries its own risks. Complications include permanent brain damage, delayed awakening, cerebral thrombosis (a blood clot in the brain), cerebral ischaemia (insufficient blood flow to the brain) and death. Propofol (an anaesthetic drug given intravenously) could be given to reduce blood pressure during the anaesthetic period. We compared propofol with inhalational (gas) anaesthetics and other drugs for induced hypotension in adults and children. We included in our review four studies consisting of 278 participants. We found that propofol did not reduce measured overall blood loss in children and adults. Propofol might improve the quality of the surgical field a little, but no difference in operation time has been noted. Propofol was more reliable in achieving induced hypotension. No studies reported any adverse effects from induced hypotension with propofol. Because we found only four studies with a small total number of participants, these results should be interpreted with caution. More studies are needed to confirm whether any important benefit is associated with the use of propofol.

Résumé simplifié

Hypotension induite avec du propofol sous anesthésie lors pour la chirurgie endoscopique des sinus

La chirurgie endoscopique fonctionnelle des sinus (CEFS) est une technique mini-invasive utilisée pour traiter les patients souffrant de sinusite chronique (définie par une inflammation de la membrane muqueuse dans les sinus paranasaux (cavités d'air dans les os du visage) et du liquide au sein de la cavité sinusale qui persiste plus de 12 semaines). Le chirurgien utilise un petit endoscope (caméra miniature) qu'il insère dans le nez pour obtenir une vue rapprochée des sinus. Le principal problème avec la CEFS dans la pratique est le saignement durant l'opération. Le sang remplit le nez ou se dépose sur l'objectif de la caméra, masquant la vue du chirurgien. Si le saignement est grave, le chirurgien peut être obligé d'abandonner l'opération sans atteindre son but. Le saignement peut rallonger la durée de la procédure ou peut endommager accidentellement les structures environnantes, y compris les yeux et le cerveau. Une méthode de réduction du saignement sous anesthésie générale est l'hypotension induite, qui implique la diminution volontaire de la pression artérielle du patient jusqu'à une valeur sous la normale. La diminution de la pression artérielle moyenne (PAM) chez les patients ayant une pression artérielle normale vise à améliorer le champ chirurgical et limiter la perte de sang. Toutefois, la diminution de la pression artérielle comporte ses propres risques. Les complications incluent des lésions cérébrales permanentes, un réveil retardé, une thrombose cérébrale (caillot sanguin formé dans le cerveau), une ischémie cérébrale (insuffisance du flux sanguin jusqu'au cerveau) et le décès. Le propofol (médicament anesthésique administré par voie intraveineuse) pourrait être administré pour réduire la pression artérielle pendant la période d'anesthésie. Nous avons comparé le propofol à des gaz anesthésiques administrés par inhalation et d'autres médicaments pour l'hypotension induite chez les adultes et les enfants. Nous avons inclus dans notre revue quatre études totalisant 278 participants. Nous avons estimé que le propofol n'avait pas réduit la perte de sang globale mesurée chez les enfants et les adultes. Le propofol pourrait améliorer quelque peu la qualité du champ chirurgical, mais aucune différence n'a été notée pour la durée de l'opération. Le propofol était plus fiable pour provoquer l'hypotension induite. Aucune étude n'a rendu compte des effets indésirables liés à l'hypotension induite avec le propofol. Ces résultats doivent être interprétés avec prudence car nous n'avons trouvé que quatre études représentant un petit nombre total de participants. D'autres études seront nécessaires pour confirmer qu'un bénéfice important est associé à l'utilisation du propofol.

Notes de traduction

Traduit par: French Cochrane Centre 16th July, 2013
Traduction financée par: Pour la France : Minist�re de la Sant�. Pour le Canada : Instituts de recherche en sant� du Canada, minist�re de la Sant� du Qu�bec, Fonds de recherche de Qu�bec-Sant� et Institut national d'excellence en sant� et en services sociaux.

Summary of findings(Explanation)

Summary of findings for the main comparison. Propofol versus inhalation anaesthetics for functional endoscopic sinus surgery (FESS)
Propofol compared with inhalation anaesthetics for functional endoscopic sinus surgery (FESS)
Patient or population: participants with functional endoscopic sinus surgery (FESS).
Settings: deliberate hypotension during general anaesthesia.
Intervention: propofol versus inhalation anaesthetics.
OutcomesIllustrative comparative risks* (95% CI)No. of Participants
(studies)
Quality of the evidence
(GRADE)
Comments
Assumed riskCorresponding risk
Inhalation agentsPropofol
Total blood loss (millilitres)ChildrenMean 120 millilitresMean difference -20.00 millilitres (-39.23 to -0.77)70 (1)⊕⊝⊝⊝
Low
One study only and both random sequence generation and allocation concealment status were unclear.
Quality of surgical field (0-5 scales)Mean 2.55 scaleMean difference -0.64 scale (-0.91 to -0.37)277 (4)⊕⊕⊝⊝
Low
Three studies had unclear random sequence generation. Three studies had unclear allocation concealment.
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval.
GRADE Working Group grades of evidence:
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

Background

Description of the condition

Chronic sinusitis is a common disease in any age group and may be defined as inflammation of the mucous membrane in the paranasal sinuses and fluid within the sinus cavity that lasts longer than 12 weeks. The primary treatments for chronic sinusitis are antibiotics and topical nasal steroids. If these measures are not successful, then sinus surgery is usually considered (Kennedy 2001; Yanez 2003). The most common procedure is functional endoscopic sinus surgery (FESS). In this minimally invasive technique, the sinus air cells and openings into the nose (ostia) are opened under direct visualization through an endoscopic technique (Khalil 2006), thereby restoring sinus ventilation (Stammberger 1991).

The use of FESS has now become widely accepted (Khalil 2006). The number of FESS procedures that are performed has grown (Dalziel 2003; Dalziel 2006; Danielsen 2003). Compared with other more traditional methods, endoscopic sinus surgery is associated with fewer complications and greater symptomatic improvement (Dalziel 2006), including less postoperative pain, no external scars and more rapid recovery. Complications related to FESS include bleeding into the nose that obscures the surgical field, bleeding into adjacent structures (including around the eyes), damage to the structures around the eye, epiphora (excessive tear production), loss of vision, cerebrospinal fluid leak, damage to intracranial structures and death (Maniglia 1991; May 1994; Reinhart 1993; Stankiewicz 2001). The main problem in practice is intraoperative bleeding because even small areas of bleeding can reduce visibility during FESS, and this can result in abandonment of the procedure or unintentional destruction of surrounding structures.

Description of the intervention

Deliberate hypotension can reduce blood loss in many situations, including orthopaedic surgery, maxillofacial surgery and neurosurgery (Dutton 2004; Tobias 2002). Any technique of deliberate hypotension during general anaesthesia aims to lower the mean arterial blood pressure (MAP) to values between 50 and 65 mm Hg in patients with normal blood pressure, with the goal of significantly reducing blood loss (Clincikas 2003). Although the precise mechanism varies with the technique used, deliberate hypotension is usually the result of a reduction in cardiac output, blood pressure or a combination of these factors (Aken 2000). Deliberate hypotension can reduce blood loss in FESS by between 80 and 141 millilitres (Clincikas 2003; Elsharnouby 2006). However, deliberate hypotension is not without potential complications, which include permanent cerebral damage, delayed awakening, cerebral thrombosis, brain ischaemias and death (Aken 2000).

Techniques for deliberate hypotension include controlling venous return (e.g. through positioning of the patient) and providing various pharmacological interventions including volatile anaesthetics (halothane, isoflurane, sevoflurane, desflurane), direct-acting vasodilator drugs (sodium nitroprusside, nitroglycerine, hydralazine), trimethaphan, alpha-adrenergic receptor blocking drugs (phentolamine, urapidil), beta-adrenergic receptor blocking drugs (propranolol, esmolol), combined alpha- and beta-adrenergic receptor blocking drugs (labetalol), calcium channel blockers (nicardipine) and prostaglandin E1 (Aken 2000; Dodds 2001; Morgan 2002). Disadvantages are associated with each of these approaches. For example, the use of nitroprusside or nitroglycerine may require escalating doses because of tachyphylaxis (Aken 2000), nitroprusside in large doses may result in cyanide intoxication (Bendo 2001) and both require invasive monitoring of arterial blood pressure (Aken 2000). Volatile anaesthetics can prolong recovery and delay discharge (Aken 2000).

How the intervention might work

More recently, deliberate hypotension using the anaesthetic agent propofol has become popular. Propofol is commonly used during anaesthesia both as an induction agent and for maintenance of anaesthesia. It induces a state of general anaesthesia by facilitating inhibitory neurotransmission mediated by gamma-aminobutyric acid (GABA). Propofol has rapid onset and recovery times with a short half-life and duration of action (Reves 2005). Disadvantages of propofol are that it is painful on injection and administration can decrease arterial blood pressure and cardiac output. Changes in blood pressure can be rapidly achieved in response to bolus doses or infusion, as required (Reves 2005).

Why it is important to do this review

For achieving deliberate hypotension, many studies have found that propofol seemed to be more effective in reducing blood loss than volatile anaesthetics (Aken 2000; Blackwell 1993; Dodds 2001; Eberhart 2003; Morgan 2002; Pavlin 1999). If propofol is superior to alternative agents in attaining deliberate hypotension for FESS, then this would be important information for the anaesthetist in choosing the more appropriate technique. If, on the other hand, any clear disadvantages are associated with propofol, the information is equally important to the clinical practitioner.

Objectives

We aimed to compare the use of propofol versus other techniques for achieving deliberate intraoperative hypotension during FESS procedures with regard to blood loss and operative conditions.

Methods

Criteria for considering studies for this review

Types of studies

We included all published and unpublished randomized controlled trials (RCTs).

Types of participants

We included participants of any age who received general anaesthesia for FESS.

Types of interventions

We compared propofol for deliberate hypotension (MAP lowered to values at or below 65 mm Hg) with other deliberate hypotension techniques.

Types of outcome measures

Primary outcomes
  • Total blood loss (blood loss during surgery measured as blood collected in the suction apparatus and by weight of the nasal swabs; TBL).

Secondary outcomes
  • Operator assessment of quality of surgical field: a 6-point scale (0 = no bleeding; 1 = slight bleeding and no suctioning of blood required; 2 = slight bleeding and occasional suctioning required; 3 = slight bleeding and frequent suctioning required (bleeding threatens surgical field a few seconds after suctioning is removed); 4 = moderate bleeding (frequent suctioning required, bleeding threatens surgical field directly after suction is removed); 5 = severe bleeding (constant suctioning required, bleeding appears faster than can be removed by suction, surgical field severely threatened) (Fromme 1986).

  • Operation time as assessed in minutes (from the start of the operation until the end).

  • Incidence of failed deliberate hypotension (defined as failure to reduce MAP to values below 65 mm Hg).

  • Mortality within 24 hours after surgery.

  • Complications from the deliberate hypotension technique as reported in a trial (e.g. permanent cerebral damage, delayed awakening, cerebral thrombosis, brain ischaemia).

  • Need for reoperation.

  • Need for admission to intensive care or a high-dependency area postoperatively.

Search methods for identification of studies

Electronic searches

We searched the current issue of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2012, Issue 1), MEDLINE Ovid SP (1950 to April 2012), EMBASE Ovid SP (1980 to April 2012), LILACS (1982 to April 2012) and ISI Web of Science (1946 to April 2012).

We developed a specific search strategy for each database. We based each search strategy on that developed for MEDLINE (Appendix 1) (please see Appendix 2 (CENTRAL), Appendix 3 (EMBASE), Appendix 4 (LILACS) and Appendix 5 (ISI Web of Science)).

Searching other resources

We also identified trials by:

  • In April 2012, searching specialist journals (i.e. Anesthesia and Analgesia, Anesthesiology, Anaesthesia, Acta Anaesthesiologica Scandinavica, British Journal of Anaesthesia, Canadian Journal of Anaesthesia, European Journal of Anaesthesia, Laryngoscope, American Journal of Otolaryngology, European Archives of Otorhinolaryngology).

  • Searching conference proceedings and abstracts (The American Society of Anesthesiologists (ASA), International Anaesthesia Research Society (IARS), European Society of Anaesthesiologists (ESA)).

  • Contacting known trialists, experts and medical or pharmaceutical companies for unpublished trials.

  • Searching grey literature (such as SIGLE).

  • Checking the reference list of relevant articles.

We did not apply any language restriction.

Data collection and analysis

Selection of studies

Two review authors (BP and BS) independently scanned the titles and abstracts of reports identified by electronic database and hand-searching of journals. We obtained and assessed the full article of any possibly relevant trials according to the definitions provided in the criteria for considering studies for this review. We resolved any disagreement through discussion with the third review author (LM).

Data extraction and management

One review author (BS) summarized data from all included trials on a standardized data extraction form (Appendix 6); those data were checked by a second review author (BP). We resolved any disagreement through discussion.

Assessment of risk of bias in included studies

Two authors (BP and BS) assessed the methodological quality of each trial in accordance with the guidelines described by The Cochrane Collaboration in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).

Our assessment criteria were as follows:

  • Random sequence generation (selection bias): low, unclear, high risk.

  • Allocation concealment (selection bias): low, unclear, high risk.

  • Blinding (performance bias and detection bias): low, unclear, high risk.

  • Incomplete outcome data (attrition bias): low, unclear, high risk.

  • Selective reporting (reporting bias): low, unclear, high risk.

We independently evaluated and ranked the quality of each trial. We resolved any conflicts in assessment through discussion and, if necessary, through evaluation by a third review author (LM).

Measures of treatment effect

For proportions (dichotomous outcomes; mortality, complications, incidence of failed deliberate hypotension, need for reoperation, need for postoperative admission to intensive care or a high-dependency area), we used relative risk (RR). Continuous data (blood loss during surgery, quality of surgical field, operation time) were analysed as mean differences (MDs) using the inverse variance method. Continuous data that used different scales were analysed using standardized MDs when appropriate.

Unit of analysis issues

No unit of analysis issues were encountered.

Dealing with missing data

We attempted to contact the authors for the missing data. If authors did not respond, we extracted the available data from the publication. If data were missing because of dropping out of participants or losses to follow-up, we planned to conduct a primary analysis based on complete data and a sensitivity analysis with missing data imputed based on worst-case and best-case scenarios.

Assessment of heterogeneity

We assessed statistical heterogeneity using the I2 statistic (Higgins 2011) and gave consideration to the appropriateness of pooling and meta-analysis. We explored heterogeneity and performed subgroup analyses when appropriate.

Assessment of reporting biases

If possible, we planned to assess reporting biases (such as publication bias) by using funnel plots if appropriate (Egger 1997).

Data synthesis

All analyses were made on an intention-to-treat (ITT) basis where possible. When I2 was less than 40% and the P value from the Chi2 test was higher than 0.10, we used a fixed-effect model for pooling data. Otherwise we pooled data using a random-effects model (Egger 1997).

Subgroup analysis and investigation of heterogeneity

We intended to perform subgroup analysis in the presence of statistical heterogeneity (I2 > 40%) or an indication of clinical heterogeneity and considered the following potential subgroups:

  • Age group: younger than 15 (children), 15 to 65 (adult), older than 65 years of age (elderly).

  • MAP level.

  • Anaesthetic technique (inhalation maintenance anaesthesia, intravenous maintenance anaesthesia).

  • Hypotensive drug combination.

Sensitivity analysis

We considered sensitivity analysis based on risk of bias and allocation of missing data. For the latter, we intended to investigate the influence on our estimate of overall effect of allocating missing data according to both a best-case (all missing data in the propofol group assumed to have a good outcome and in the comparator group to have a poor outcome) and a worst-case (the opposite) scenario.

Results

Description of studies

Results of the search

We identified 4671 citations from database searches, journal searches, conference proceedings and citation reviews (Figure 1). After screening by title and then by abstract, we obtained full-text copies of eight citations that were potentially eligible for inclusion in the review. No trials are awaiting assessment. Four trials (278 participants) met our inclusion criteria. One trial (Gomez-rivera 2011) was an ongoing study.

Figure 1.

Study flow diagram.

Included studies

We included four trials in this review (Eberhart 2003; Ragab 2010; Tirelli 2004; Wormald 2005; see Characteristics of included studies). Eberhart 2003 and Tirelli 2004 compared propofol infusion and remifentanil versus isoflurane and alfentanil/fentanyl in adults. Ragab 2010 compared propofol infusion and remifentanil versus isoflurane, fentanyl and esmolol in children. Wormald 2005 compared propofol infusion and remifentanil versus sevoflurane and fentanyl. All trials reported surgical field grade as median, mean (SD) and mean (SE). We contacted the principal authors (Eberhart 2003; Wormald 2005) and received additional information by e-mail. Eberhart 2003 also reported blood loss, operation time and failure of deliberate hypotension. Wormald 2005 reported standard error; we converted it to standard deviation.

Excluded studies

We excluded five trials because they did not directly compare the efficacy of propofol and an alternative treatment in maintaining deliberate intraoperative hypotension (Ahn 2008; Ankichetty 2012; Beule 2007; Pavlin 1999; Sivaci 2004; see Characteristics of excluded studies).

Risk of bias in included studies

Please see Figure 2; Characteristics of included studies for our assessment of the risk of bias in the included studies.

Figure 2.

Methodological quality summary: review authors' judgements about each methodological quality item for each included study.

Allocation

Eberhart 2003; Ragab 2010; Tirelli 2004 and Wormald 2005 reported unclear information on allocation concealment.

Blinding

Four trials (Eberhart 2003; Ragab 2010; Tirelli 2004 and Wormald 2005) had adequate blinding among patient, surgeon and assessor.

Incomplete outcome data

All studies had complete outcome data.

Selective reporting

We found that all prespecified outcomes were reported in trials. No selective reporting of outcomes was noted in any of the studies.

Other potential sources of bias

We remained mindful of the potential weakness of data for TBL measurement. Two trials reported TBL, although it is difficult to measure exact blood loss in both the surgical field and the pharynx. This outcome needs to be interpreted with caution. In addition, propofol dose, inhalation anaesthetic agents and analgesic drug doses differed between trials, which may have biased the outcome of our analysis.

Effects of interventions

See: Summary of findings for the main comparison Propofol versus inhalation anaesthetics for functional endoscopic sinus surgery (FESS)

Primary outcomes

  • Total blood loss (comparison 01).

    • Two trials reported this outcome (Eberhart 2003; Ragab 2010) and included 158 participants (72% of the participants in this review). Eberhart 2003 enrolled 88 adults, and Ragab 2010 studied 70 children. Because of concern about pooling the results of children and adults, we reported each age group separately.

    • In adults, Eberhart 2003 compared propofol with isoflurane and reported a median TBL of 100 millilitres (interquartile range 50 to 240 millilitres) in the propofol group versus a median TBL of 170 millilitres (interquartile range 100 to 270 millilitres) in the isoflurane group. This difference was not statistically significant (P = 0.12).

    • In children, Ragab 2010 compared propofol with isoflurane and reported a mean (SD) TBL of 100 (39) millilitres in the propofol group versus 120 (43) millilitres in the isoflurane group. This difference was not statistically significant (P = 0.084).

Secondary outcomes

  • Quality of surgical fieldmean scores (comparison 02).

    • Four trials reported on this outcome using a 6-point scale (Eberhart 2003; Ragab 2010; Tirelli 2004; Wormald 2005), and all 277 participants were included in this outcome. Three compared propofol with isoflurane (Eberhart 2003; Ragab 2010; Tirelli 2004), and one compared propofol with sevoflurane (Wormald 2005). Only one trial (Ragab 2010) enrolled children.

    • The mean score in the propofol group was 1.77 and in the control group 2.55. This difference was statistically significant (MD = 0.64 better with propofol, 95% CI 0.37 to 0.91, P < 0.00001, I268%). Some heterogeneity was noted between trials; therefore a random-effects model was used. Heterogeneity was not explained by a subgroup analysis. It might be explained by a small 6-point scale.

    • In adults, the mean score in the propofol group was 1.96 and in the control group 2.87. This difference was statistically significant (MD = -0.75, 95% CI -1.10 to -0.40, P < 0.00001, I2 67%; Analysis 1.1).

    • In children, the mean score in the propofol group was 1.2 and in the isoflurane group 1.6. This difference was statistically significant (MD = -0.40, 95% CI -0.64 to -0.16, P < 0.001; Analysis 1.1).

  • Operation time (comparison 03).

    • Three trials (Eberhart 2003; Ragab 2010; Wormald 2005) reported this outcome (minutes) and included 214 participants (77% of the participants in this review). These authors reported a mean operation time of 91.51 minutes in the propofol group versus 89.42 minutes in the control group. This difference was not significant (MD = -4.81 minutes, 95%CI -11.82 to 2.21, P = 0.53, I2 28%; Analysis 1.2).

  • Failure of deliberate hypotension (comparison 04).

    • Only Eberhart 2003 reported this outcome and included 88 participants (32% of the participants in this review). These authors reported a failure rate of deliberate hypotension of 8.89% in the propofol group and 37.21% in the control group. This difference was significant (RR = 0.24, 95%CI 0.09 to 0.66, P = 0.0056).

  • Mortality within 24 hours after surgery (comparison 05).

    • No trial reported any mortality in either group.

  • Complications from the deliberate hypotension technique (comparison 06).

    • No trial reported any complications in either group.

  • Need for reoperation (comparison 07).

    • No trial reported any need for reoperation in either group.

  • Need for admission to intensive care or a high-dependency area postoperatively (comparison 08).

    • No trial reported any need for admission to intensive care in either group.

Discussion

Summary of main results

The TBL was reported only in a single study involving children and in a single study in adults; therefore we could not pool data for our primary outcome. Total measured blood loss did not differ between groups in adults or in children. A statistically significant improvement in the quality of the surgical field was observed with deliberate hypotension using propofol when compared with deliberate hypotension using inhalation anaesthetics (MD = 0.64 on a 6-point scale). This is a small improvement (less than one category), and it is not clear whether this difference is clinically important. Operation time did not differ between groups. A single study comparing propofol with isoflurane showed that the use of propofol resulted in fewer failures of deliberate hypotension (RR = 0.24, 95% CI 0.09 to 0.66). No deaths were reported in any of the studies.

Overall completeness and applicability of evidence

The main limitation of these findings is the small number of studies. This review includes the findings from only four trials, and the evidence was insufficient to allow firm conclusions to be drawn for many of our outcome measures, particularly as many of these studies did not report many of our clinical outcomes at all, including adverse effects. The overall applicability of the results of this review is limited because we have been unable to perform an adequate assessment of benefit to risk.

We were unable to perform any planned subgroup analyses, but of the two studies reporting our primary outcome, one enrolled children (Ragab 2010) and the other adults (Eberhart 2003). We were unable to perform sensitivity analysis by risk of bias or to determine the effect of allocating missing data because of insufficient data.

We were unable to report TBL in adults in summary of findings tables because Eberhart 2003 reported only median values (25th/75th percentile) of TBL.

Despite the many drugs that have been used to induce deliberate hypotension during general anaesthesia, such as vasodilators, beta-adrenergic blockers, calcium channel blockers and opioids, only trials of propofol and inhalational anaesthetic agents have been reported with deliberate hypotension. The only agents compared with propofol were isoflurane (three studies) and sevoflurane (one study). Even though this review suggests a slightly lower quality of the surgical field with inhalational agents compared with propofol, results may lack clinical significance because of the small difference.

Quality of the evidence

Although all four included studies were randomized, some elements of the methodology suggest a moderate risk of bias in all trials (Eberhart 2003; Ragab 2010; Tirelli 2004; Wormald 2005). Details are presented in the risk of bias tables (Figure 2).

The effect of propofol on the quality of the surgical field may have been biased because all of the included trials used a combination of propofol and remifentanil (an ultra-short-acting opioid) during the operation, and in the inhalation anaesthetics group, all participants received a longer-acting opioid (alfentanil or fentanyl). Propofol was therefore not the only difference in the therapeutic regimen, and these data should be properly interpreted as the effect of 'propofol with remifentanil by infusion' compared with 'volatile anaesthesia plus intermittent fentanyl or alfentanil'. This is an important qualification to our findings because remifentanil has been shown to be effective in improving the surgical field. For example, one RCT (Degoute 2001) showed that propofol and remifentanil during deliberate hypotension improved the surgical field for tympanoplasty. This may be mediated through the effect of remifentanil on lowering heart rate, cardiac output and blood pressure. Remifentanil may be rapidly titrated to produce the desired level of analgesia; this may contribute to the achievement of a target arterial blood pressure and may be responsible at least in part for the apparent success of propofol in this regard.

Measurement of blood loss during FESS is difficult and may be inaccurate in these trials. Concealed blood loss (especially loss into the gut), although presumably similar across all groups, might be associated with underestimation of losses. In any case, this outcome was reported in only two trials.

Finally, although we could not show any difference in mortality or morbidity between the techniques examined in this review, this should not be taken to mean that we can exclude such consequences with any confidence. Adverse events are rare during FESS (e.g. the mortality rate has been reported to be 0.02% to 0.34% (Aken 2000)), and a much larger data set would be required to reliably confirm or refute any effects of using propofol instead of an inhalational agent. In general, therefore, reliable conclusions may not be drawn from the four included studies.

Potential biases in the review process

We followed the standard approaches of the Cochrane review process and believe that no specific biases apply to this review other than those already discussed.

Agreements and disagreements with other studies or reviews

Two published narrative reviews have compared surgical field and blood loss during FESS. Amorocho 2010 concluded that propofol general anaesthesia improved the surgical field and reduced blood loss, and Baker 2010 concluded that propofol general anaesthesia improved the surgical field but did not reduce blood loss during surgery. Although not generally in conflict with our findings, these reviews included both normotensive and deliberate hypotensive techniques, so they cannot be directly compared with this review.

Authors' conclusions

Implications for practice

Deliberate hypotension with propofol for FESS surgery may improve the quality of the surgical field in normotensive patients. There is little reliable evidence in this area on which to base firm conclusions. This review is unlikely to change current practice, and experienced anaesthetists are unlikely to alter their preferred technique on the basis of these findings.

Implications for research

This systematic review provided insufficient evidence to allow us to make firm recommendations about deliberate hypotension with propofol versus inhalation anaesthetics during anaesthesia for FESS. Larger RCTs with good methodology comparing deliberate hypotension with propofol or other techniques are required before effectiveness can be adequately evaluated. Comparision studies of propofol with other antihypertensive drugs (vasodilators, beta-adrenergic blockers, calcium channel blockers and opioids) for deliberate hypotension during general anaesthesia are required. The effect of opioids on blood loss during deliberate hypotension should be explored. A large prospective database would be required to reliably confirm or refute any complications of using deliberate hypotension with propofol.

Acknowledgements

We would like to thank Mike Bennett (content editor), James W. Fairley and Leopold Eberhart (peer reviewers) for their help and editorial advice during the preparation of the protocol for this systematic review. We thank Karen Hovhannisyan for his search strategy and data searching. We would like to thank Jane Cracknell, Mike Bennett (content editor), Marialena Trivella (statistical editor), James W Fairley and Leopold Eberhart (peer reviewers) and Katriona Methven (representative of the Cochrane Consumer Network) for their help and editorial advice during the preparation of this review

Data and analyses

Download statistical data

Comparison 1. Propofol versus inhalation anaesthetics
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Quality of surgical field (age group)4277Mean Difference (IV, Random, 95% CI)-0.64 [-0.91, -0.37]
1.1 Adult3207Mean Difference (IV, Random, 95% CI)-0.75 [-1.10, -0.40]
1.2 Children170Mean Difference (IV, Random, 95% CI)-0.40 [-0.64, -0.16]
2 Operation time (minutes)3214Mean Difference (IV, Fixed, 95% CI)-4.81 [-11.82, 2.21]
2.1 Adult2144Mean Difference (IV, Fixed, 95% CI)3.89 [-9.64, 17.42]
2.2 Children170Mean Difference (IV, Fixed, 95% CI)-8.0 [-16.20, 0.20]
Analysis 1.1.

Comparison 1 Propofol versus inhalation anaesthetics, Outcome 1 Quality of surgical field (age group).

Analysis 1.2.

Comparison 1 Propofol versus inhalation anaesthetics, Outcome 2 Operation time (minutes).

Appendices

Appendix 1. Search strategy for MEDLINE (Ovid SP)

1 exp Propofol/
2 exp Hypotension/
3 hypoten$.mp.
4 exp Anesthesia, General/
5 Anesthesia-Inhalation/
6 an?esthesia.mp.
7 (propofol or diprivan or disoprofol or pofol) .mp.
8 (1 or 2 or 3 or 4 or 5 or 6 or 7)
9 exp Paranasal-Sinus-Diseases/
10 exp Paranasal-Sinuses/
11 Endoscopy/
12 (surg$ adj3 (paranas$ or endoscop$ or microscop$)).mp.
13 nasal.mp.
14 (sinus$ adj3 (maxilliary or frontal or ethmoid or sphenoid)) .mp.
15 exp Ethmoid-Sinus/
16 exp Frontal-Sinus/
17 exp Maxillary-Sinus/
18 exp Sphenoid-Sinus/
19 Paranasal-Sinus-Neoplasms/ or Sinusitis/
20 (intranasal or paranasal or endonasal).mp.
21 Nasal-Cavity/
22 exp Otorhinolaryngologic-Surgical-Procedures/
23 (surg$ adj3 (paranas$ or endoscop$ or microscop$)).mp. and (nasal or endonas$ or intranas$ or paranas$).mp.
24 (sinus$ and (maxilliary or frontal or ethmoid or sphenoid)).mp.
25 rhin$ not rhinoceros
26 (9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19 or 20 or 21 or 22 or 23 or 24 or 25)
27 (8 and 26)
28 (randomized controlled trial.pt. or controlled clinical trial.pt.or randomized.ab. or placebo.ab. or clinical trials as topic.sh. or randomly.ab. or trial.ti.) not (animals not (humans and animals)).sh.
29 (27 and 28)

Appendix 2. Search strategy for CENTRAL (The Cochrane Library)

#1 MeSH descriptor Propofol explode all trees
#2 MeSH descriptor Hypotension explode all trees
#3 hypoten* in All Text
#4 MeSH descriptor Anesthesia, General explode all trees
#5 MeSH descriptor Anesthesia, Inhalation explode all trees
#6 an?esthesia in All Text
#7 (propofol in All Text or diprivan in All Text or disoprofol in All Text or pofol in All Text)
#8 (#1 or #2 or #3 or #4 or #5 or #6 or #7)
#9 MeSH descriptor Paranasal Sinus Diseases explode all trees
#10 MeSH descriptor Paranasal Sinuses explode all trees
#11 MeSH descriptor Endoscopy explode all trees
#12 (surg* in All Text near/6 paranas* in All Text)
#13 (surg* in All Text near/6 endoscop* in All Text)
#14 (surg* in All Text near/6 microscop* in All Text)
#15 nasal in All Text
#16 (sphenoid in All Text and sinus* in All Text)
#17 (ethmoid in All Text and sinus* in All Text)
#18 (frontal in All Text and sinus* in All Text)
#19 MeSH descriptor Ethmoid Sinus explode all trees
#20 MeSH descriptor Frontal Sinus explode all trees
#21 MeSH descriptor Maxillary Sinus explode all trees
#22 MeSH descriptor Sphenoid Sinus explode all trees
#23 MeSH descriptor Paranasal Sinus Neoplasms explode all trees
#24 (ntranasal in All Text or paranasal in All Text or endonasal in All Text)
#25 MeSH descriptor Nasal Cavity explode all trees
#26 MeSH descriptor Otorhinolaryngologic Surgical Procedures explode all trees
#27 (sinus* in All Text and (maxillary in All Text or frontal in All Text or ethmoid in All Text or sphenoid in All Text) )
#28 rhin* in All Text
#29 (#9 or #10 or #11 or #12 or #13 or #14 or #15 or #16 or #17 or #18 or #19 or #20 or #21 or #22 or #23 or #24 or #25 or #26 or #27 or #28)
#30 (#8 and #29)

Appendix 3. Search strategy for EMBASE (Ovid SP)

1 exp propofol/
2 exp hypotension/
3 general-anesthesia/
4 inhalation-anesthesia/
5 an?esthesia.mp.
6 hypoten$.mp.
7 (propofol or diprivan or disoprofol or pofol).mp.
8 (1 or 2 or 3 or 4 or 5 or 6 or 7)
9 paranasal-sinus-disease/
10 exp paranasal-sinus/
11 endoscopy/
12 exp ethmoid-sinus/
13 exp ethmoid-sinus/
14 exp maxillary-sinus/
15 exp sphenoid-sinus/
16 paranasal-sinus-tumor/
17 paranasal-sinusitis/
18 exp nose-cavity/
19 ear-nose-throat-surgery/
20 (surg$ adj3 (paranas$ or endoscop$ or microscop$)).mp.
21 nasal.mp.
22 (sinus$ adj3 (maxilliary or frontal or ethmoid or sphenoid)).mp.
23 (intranasal or paranasal or endonasal).mp.
24 (surg$ (paranas$ or endoscop$ or microscop$)).mp. and (nasal or endonas$ or intranas$ or paranas$).mp.
25 (sinus$ and (maxilliary or frontal or ethmoid or sphenoid)).mp.
26 (rhin$ not rhinoceros).mp.
27 (9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 or 17 or 18 or 19 or 20 or 21 or 22 or 23 or 24 or 25 or 26)
28 (8 and 27)
29 ((RANDOMIZED-CONTROLLED-TRIAL/ or RANDOMIZATION/ or CONTROLLED-STUDY/ or MULTICENTER-STUDY/ or PHASE-3-CLINICAL-TRIAL/ or PHASE-4-CLINICAL-TRIAL/ or DOUBLE-BLIND-PROCEDURE/ or SINGLE-BLIND-PROCEDURE/) or ((RANDOM* or CROSS?OVER* or FACTORIAL* or PLACEBO* or VOLUNTEER*) or ((SINGL* or DOUBL* or TREBL* or TRIPL*) adj3 (BLIND* or MASK*))).ti,ab) not (animals not (humans and animals)).sh.
30 (28 and 29)

Appendix 4. Search strategy for LILACS (via BIREME interface)

("PROPOFOL" or "PROPOFOL/" or "HYPOTENSION" or "HYPOTENSION, CONTROLLED/" or "ANAESTHESIA" or "ANAESTHESIC" or "ANAETHESIA" or "ANAETHESIC" or "ANESTHESIA" or "ANESTHESIA AND ANALGESIA" or "ANESTHESIA, CLOSED-CIRCUIT/") and (rhinosinusal or paranasal or nasal or intranasal or endonasal or "NASAL CAVITY/" or "PARANASALE" or "PARANASALES" or "PARANASALS" or "ETHMOID SINUS" or "ETHMOID SINUS/" or "SPHENOID SINUS" or "SPHENOID SINUS/" or "SPHENOID SINUSITIS/" or "FRONTAL SINUS" or "FRONTAL SINUS/" or "FRONTAL SINUSITIS/" or "nasal" or "Endoscopy" or "sinus")

Appendix 5. Search strategy for ISI Web of Science

#1 TS=(propofol or diprivan or disoprofol or pofol)
#2 TS=hypoten*
#3 TS=an$esthesia
#4 #1 or #2 or #3
#5 TS=(paranasal or nasal or intranasal or endonasal)
#6 TS=(surg* SAME (paranas* or endoscop* or microscop*))
#7 TS=(sinus* SAME (maxilliary or frontal or ethmoid or sphenoid))
#8 TS=Paranasal SAME TS=Sinus*
#9 TS=Nasal Cavity
#10 TS=rhin*
#11 #5 or #6 or #7 or #8 or #9 or #10
#12 TS=(random* or clinical or control*) SAME TS=trial*
#13 TS=(random* or clinical or control*) and TS=trial*
#14 TS=(random SAME allocat*)
#15 TS=random*
#16 TS=(singl* or doubl* or trebl* or tripl*) SAME
TS=(blind* or mask* or method*)
#17 TS=placebo*
#18 #17 OR #16 OR #15 OR #14 OR #13 OR #12
#19 #18 AND #11 AND #4

Appendix 6. Data extraction form

Data Extraction form Review
Study ID:Medline Journal ID:Language:
Authors:
Year of publication:Country:Type of study
Comment on study design

Randomizations and

allocation concealment

Adequate: e.g. numbered, sealed opaque envelopes 
Unclear 
Inadequate 
Not used 
Blinding of treatment Adequate (patient, physician, assessor)  
Unclear 
Inadequate (patient, physician, assessor)  
Blinded outcome assessment Adequate 
Unclear 
Inadequate 
Use of intention-to-treat analysis Yes           
No 
No information 
PARTICIPANTS:
Number of eligible participantsNumber of males
Number enrolled in studyNumber of females
Age<1515-65> 65
Intervention:
Propofol 
Other drug 
COMMENT ON TREATMENT:
withdrawalsYesNoUnclear
Outcome Propofol Other drug
Blood loss  
Visibility of operative field  
Operation time  
Failed deliberate hypotension  
Need for reoperation  
Need for admission ICU  
Others complication  
Changes in protocol:
Contact with authors:
Comment on this study:

History

Protocol first published: Issue 3, 2007
Review first published: Issue 6, 2013

DateEventDescription
7 April 2009AmendedConverted to new review format.

Contributions of authors

Conceiving the review: Suhattaya Boonmak (BS), Polpun Boonmak (BP).
Co-ordinating the review: BS, BP, Malinee Laopaiboon (LM).
Undertaking manual searches: BS, BP.
Screening search results: BS, BP.
Organizing retrieval of papers: BS, BP.
Screening retrieved papers against inclusion criteria: BS, BP.
Appraising quality of papers: BS, BP.
Abstracting data from papers: BS, BP.
Writing to authors of papers for additional information: BS, BP.
Providing additional data about papers: BS, BP.
Obtaining and screening data on unpublished studies: BS, BP.
Providing data management for the review: BS, BP, LM.
Entering data into Review Manager (RevMan 5.1): BS, BP.
Obtaining RevMan statistical data: BS, BP, LM.
Performing other statistical analysis while not using RevMan: LM.
Performing double entry of data: (data entered by person one: BS; data entered by person two: BP).
Interpreting data: LM.
Making statistical inferences: LM.
Writing the review: BS, BP, LM.
Securing funding for the review: BS.
Performing previous work that served as the foundation of the present study: BS, BP.
Serving as guarantor for the review (one author): BP.
Taking responsibility for reading and checking review before submission: BS, BP.

Declarations of interest

Polpun Boonmak: none known.

Suhattaya Boonmak: none known.

Malinee Laopaiboon: received an honorarium from Thailand Research Fund, which is a non-profit organization.

Sources of support

Internal sources

  • Systematic review grant, Faculty of Medicine, Khon Kaen University, Thailand.

  • Thai Cochrane Network, Thailand.

External sources

  • The Thailand Research Fund, Thailand.

Differences between protocol and review

Quality of surgical field grading was change from "good, fair, poor" to 6-point scale surgical field.

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Eberhart 2003

Methods

Randomization and treatment allocation method: yes.
Blinding of outcome assessment: yes.
Blinding of participants: yes.

Duration: not stated.

Participants

Number: 88 participants (45 participants in propofol group vs 43 in isoflurane group).

Inclusion criteria: ASA grade I-II undergoing endoscopic surgery for chronic sinusitis.

Exclusion criteria: not stated.

Interventions
  • Propofol group (propofol and remifentanil continuous infusion keeping MAP between 60 and 70 mm Hg).

  • Isoflurane group (isoflurane and alfentanil keeping MAP between 60 and 70 mm Hg).

Outcomes
  • Blood loss (volume of suctioned blood).

  • Surgical conditions and dryness of the operation site (10-cm visual analogue scale and 6-point scale surgical field).

  • Adverse events.

  • Operation time.

  • Failure deliberate hypotension.

Notes

Additional information from Dr. LH Eberhart.

Location: Germany.

Setting: operating room.

Source of funding: not stated.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskInsufficient information to permit judgment.
Allocation concealment (selection bias)Low riskQuote: "With the use of sealed envelopes the patients were allocated to one of the following two groups immediately before start of anesthesia."
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote: "Several measures were made to keep the surgeon and the instrumenting nurse blind to the type of anesthesia. Isoflurane vapour and the display of end-tidal isoflurane concentrations on the anesthesia machine were covered. Perfusion syringes containing propofol and remifentanil were connected to each patient but were also covered."
Incomplete outcome data (attrition bias)
All outcomes
Low riskNo missing data.
Selective reporting (reporting bias)Low riskAuthors reported all pre-specified outcomes.

Ragab 2010

Methods

Randomization and treatment allocation method: yes.
Blinding of outcome assessment: yes.
Blinding of participants: yes.

Duration: not stated.

Participants

Number: 70 participants (35 participants in propofol/remifentanil group vs 35 in isoflurane/fentanyl/esmolol group).

Inclusion criteria: children undergoing endoscopic surgery for chronic sinusitis after failed maximal medical therapy after maxillary sinus aspirate or middle meatal culture and adenoidectomy.

Exclusion criteria: immunodeficiency, ciliary dyskinesia, cystic fibrosis, significant psychological problems, inability to comply with study protocol, systemic diseases affecting the nose, systemic diseases preventing participation in the study and medical and/or surgical treatments influencing the study.

Interventions
  • Propofol group (propofol and remifentanil continuous infusion keeping MAP 50 mm Hg).

  • Isoflurane group (isoflurane, fentanyl and esmolol keeping MAP 50 mm Hg).

Outcomes
  • Blood loss (volume of suctioned blood).

  • Surgical conditions and dryness of the operation site (10-cm visual analogue scale and 6-point scale surgical field).

  • Operative time.

  • Heart rate and blood pressure.

  • Adverse events.

NotesLocation: Egypt.
Setting: operating room in general hospital.
Source of funding: not stated.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskQuote:"In order to maintain exactly equal treatment numbers in both groups, randomization was done using random blocks."
Allocation concealment (selection bias)Unclear riskInsufficient information to permit judgement.
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote:"At the time of randomization, neither the patients nor the investigators were aware of the group assignment."
Incomplete outcome data (attrition bias)
All outcomes
Low riskNo missing data.
Selective reporting (reporting bias)Low riskAuthors reported all pre-specified outcomes.

Tirelli 2004

Methods

Randomization and treatment allocation method: unclear.
Blinding of outcome assessment: yes.
Blinding of participants: yes.

Duration: not stated.

Participants

Number: 64 participants (37 in isoflurane group vs 27 in propofol group).

Inclusion criteria: participants who were undergoing endoscopic sinus surgery with ASA physical status I-II.

Exclusion criteria: not stated.

Interventions
  • Propofol group (propofol infusion with remifentanil).

  • Isoflurane group (isoflurane and fentanyl).

All participants were pre-medicated with atropine and midazolam. Keep MAP between 60 and 70 mm Hg.

Outcomes
  • Surgical field grade.

  • Haemodynamic values during operation.

Notes

Location: Italy.

Setting: operating room.

Source of funding: not stated.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskInsufficient information to permit judgment.
Allocation concealment (selection bias)Unclear riskInsufficient information to permit judgment.
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote: "... the surgeon, unaware of the drug used, evaluated the quality of the surgical field."
Incomplete outcome data (attrition bias)
All outcomes
Low riskNo missing data.
Selective reporting (reporting bias)Low riskAuthors reported all pre-specified outcomes.

Wormald 2005

Methods

Randomization and treatment allocation method: unclear.
Blinding of outcome assessment: no.
Blinding of participants: yes.

Duration: not stated.

Participants

Number: 56 participants (28 in sevoflurane group vs 28 in propofol group).

Inclusion criteria: participants over 18 years of age undergoing endoscopic sinus surgery with ASA physical status I-II.

Exclusion criteria: participants receiving cardiovascular active drug and drug influencing blood coagulation.

Interventions
  • Sevoflurane group (maintained with sevoflurane 0.8% to 1.8% and bolus doses of fentanyl up to 7 mcg/kg).

  • Propofol group (target-controlled infusion 2 to 4 mcg/mL and remifentanil infusion 0.2 to 0.3 mcg/kg/min).

In both groups maintained MAP between 55 and 70 mm Hg, pulse rate < 60 beats/min. Metoprolol (0.07 mg/kg) and clonidine (1 to 2 mg/kg) were added to control.

Outcomes
  • Surgical grade (6-point scale surgical field).

  • Surgical operating time.

  • MAP, HR.

Notes

Location: Australia.

Setting: operating room.

Source of funding: not stated.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskQuote: "...randomly assigned to each arm using a random number allocation method."
Allocation concealment (selection bias)Unclear riskInsufficient information to permit judgement.
Blinding (performance bias and detection bias)
All outcomes
Low riskQuote: "Although it was not possible to blind the surgeon to the type of anesthesia, the surgeon made a conscious effort not to try to ascertain which type of anesthesia was administered. In most cases the syringe drivers for the propofol infusion were set up and present even when the patient was receiving inhalational anesthesia."
Incomplete outcome data (attrition bias)
All outcomes
Low riskNo missing data.
Selective reporting (reporting bias)Low riskAuthors reported all pre-specified outcomes.

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Ahn 2008Study group and control group did not receive deliberate hypotension.
Ankichetty 2012Study group and control group did not receive deliberate hypotension.
Beule 2007Study group and control group did not receive deliberate hypotension.
Pavlin 1999Study group and control group did not receive deliberate hypotension.
Sivaci 2004Study group and control group did not receive deliberate hypotension.

Characteristics of ongoing studies [ordered by study ID]

Gomez-rivera 2011

Trial name or titleEffects of total intravenous anesthesia vs inhalational anesthesia in endoscopic sinus surgery for chronic rhinosinusitis: a randomized controlled study.
MethodsRandomization and treatment allocation method: yes.
Blinding of outcome assessment: yes.
Blinding of participants: yes.
ParticipantsParticipants undergoing endoscopic sinus surgery for chronic rhinosinusitis.
InterventionsCompare between anaesthesia with sevoflurane/remifentanil and total intravenous anaesthesia with propofol/remifentanil.
OutcomesPrimary outcome: bleeding, surgical field visualization, assessment of platelet function, assessment of nasal blood flow to the sinonasal mucosa.
Secondary outcome: comparison of operative time, comparison of quality of recovery.
Starting dateMay 2010.
Contact informationFernando Gomez-Rivera (Memorial Hermann Hospital-Medical Center, Houston, TX 77030, United States).
Notes