Intervention Review

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Oxygen therapy for cystic fibrosis

  1. Heather E Elphick1,*,
  2. George Mallory2

Editorial Group: Cochrane Cystic Fibrosis and Genetic Disorders Group

Published Online: 25 JUL 2013

Assessed as up-to-date: 3 JUL 2013

DOI: 10.1002/14651858.CD003884.pub4


How to Cite

Elphick HE, Mallory G. Oxygen therapy for cystic fibrosis. Cochrane Database of Systematic Reviews 2013, Issue 7. Art. No.: CD003884. DOI: 10.1002/14651858.CD003884.pub4.

Author Information

  1. 1

    Sheffield Children's Hospital, Respiratory Unit, Sheffield, UK

  2. 2

    Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA

*Heather E Elphick, Respiratory Unit, Sheffield Children's Hospital, Western Bank, Sheffield, S10 2TH, UK. H.Elphick@sheffield.ac.uk. Heather.Elphick@sch.nhs.uk.

Publication History

  1. Publication Status: New search for studies and content updated (no change to conclusions)
  2. Published Online: 25 JUL 2013

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Characteristics of included studies [ordered by study ID]
Barker 1998

MethodsRandomized controlled cross-over study, single center.


Participants9 people with CF.


InterventionsSubmaximal exercise tests using cycle ergometry.


OutcomesOxygen uptake, gas exchange and exercise parameters.


NotesNo data recorded, abstract form only.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Clinicians
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskDegree of blinding not discussed.

Incomplete outcome data (attrition bias)
All outcomes
Low riskDoes not explicitly state that an intention-to-treat analysis was conducted. However, data appear to have been analyzed based on all enrolled participants; states that all participants completed all the exercises.

Selective reporting (reporting bias)Unclear riskSurvival is not specifically mentioned but there are data for all patients at the end of the study.

Changes in gas exchange and exercise tolerance reported but no statement of statistical significance.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned

Falk 2006

MethodsRandomized controlled cross-over study, single center.


Participants14 people with CF, 8 males, 6 females. Mean age 26.8 years (SD 7.1).


InterventionsSubmaximal and maximal exercise tests in room air at sea level and at the Dead Sea (natural source of oxygen enrichment).


OutcomesGas exchange and exercise test parameters.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
High riskStudy took place at sea level and at the Dead Sea and therefore participants could not be blinded.

Blinding (performance bias and detection bias)
Clinicians
High riskStudy took place at sea level and at the Dead Sea and therefore investigators could not be blinded.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskNot mentioned.

Incomplete outcome data (attrition bias)
All outcomes
Low riskAnalyzed data on participants with less than 15% exclusions; data from 3 participants not analysed as unable to complete the exercise tests.

Selective reporting (reporting bias)Unclear riskChanges in lung function, changes in gas exchange and exercise tolerance reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Gozal 1997

MethodsRandomized controlled cross-over study, single center.


Participants6 people with CF, mean age 22.3 years (13 - 28 years), 3 male, 3 female.
Two participants dropped out due to inability to tolerate the face mask and BiPAP pressure titration.


InterventionsPSGs on 2 successive nights, FiO2 0.21 and 0.30 via nasal cannula, (3rd night with nasal BiPAP).


OutcomesTotal sleep, sleep quality and architecture, REM and NREM, SaO2, tPCO2.


NotesIn-hospital PSG, data related to nasal BiPAP not included in analysis.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
High riskParticipants were aware of the nature of the intervention on the 2nd and 3rd nights of the study (oxygen or NIPPV).

Blinding (performance bias and detection bias)
Clinicians
High riskClinicians were aware of the nature of the intervention on the 2nd and 3rd nights of the study (oxygen or NIPPV).

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskNot mentioned.

Incomplete outcome data (attrition bias)
All outcomes
Low risk6 out of 8 participants completed the study; 2 participants were enrolled, but later excluded from the study as they did not tolerate NIPPV. Not relevant to this review as results for NIPPV not included in analysis.

Selective reporting (reporting bias)Unclear riskChanges in gas exchange and sleep parameters were reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Marcus 1992

MethodsRandomized controlled cross-over sstudy, single center.
Order of testing was randomized and participants were blinded to the composition of the inspired gas.


Participants22 people with CF, median age 26 years (14 to 46 years), 17 male and 5 female, matched with 21 people in a control group, median age 29 years (19 to 37 years), 11 male and 10 female. Test of 1 CF participant terminated by physician.


Interventions2 consecutive maximal exercise tests, FiO2 0.21 & 0.30.


OutcomesVO2, duration of exercise, SaO2, PETCO2, tPCO2, VE, VCO2, HR, AT.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Low riskParticipants blinded to the type of therapy administered.

Blinding (performance bias and detection bias)
Clinicians
Unclear riskNot mentioned.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskNot mentioned.

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskAnalyzed data on participants with less than 15% exclusions; all but 1 participant completed the exercise tests, but not stated whether the results were analyzed to include this participant.

Selective reporting (reporting bias)Unclear riskChanges in gas exchange and exercise tolerance were reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

McKone 2002

MethodsRandomized controlled cross-over study, single center. Single blind (participants).


Participants8 people with CF, mean age 26 years, 7 male and 1 female.
Participants completed all three exercise tests and no test was stopped by the physician.


InterventionsTwo consecutive submaximal exercise tests, FiO2 0.21 & 0.39. Order of control or oxygen tests was randomized to avoid training effect.


OutcomesVO2, duration of exercise, SaO2, HR, VE.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Low riskParticipants were blinded to the type of therapy administered.

Blinding (performance bias and detection bias)
Clinicians
High riskThe primary investigator was not blinded. It is not clear whether this person was also the outcome assessor.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskSee above. Not specifically mentioned.

Incomplete outcome data (attrition bias)
All outcomes
Low riskDoes not explicitly state that an intention-to-treat analysis was conducted. However, data appear to have been analyzed based on all enrolled participants; states that all participants completed all the exercises.

Selective reporting (reporting bias)Unclear riskChanges in gas exchange and exercise tolerance were reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Lung function data were measured but analysis not reported. This may have been because results were not significant.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Milross 2001b

MethodsRandomized controlled cross-over study.


Participants13 adults with CF, mean age 26 years.
Participants had moderate to severe lung disease (FEV1 less than 65% of predicted), were in stable clinical condition, and showed oxyhemoglobin desaturation to less then 90% on baseline PSG.
4 participants had incomplete arterial blood gas data.


InterventionsOn 3 nights, FiO2 0.21, titrated O2 via nasal cannula, and BiPAP with O2.


OutcomesTotal sleep, sleep quality and architecture, SaO2, tPCO2, respiratory events, air flow via pneumotach.


NotesIn-hospital PSG, data related to BiPAP not included in analysis.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Clinicians
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskDegree of blinding not discussed.

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskIncomplete arterial blood gas measurements for 4 participants; unclear if the results reported are for all participants.

Selective reporting (reporting bias)Unclear riskData were reported for gas exchange and sleep parameters. However, upon inspection the data appear skewed and cannot be included in meta-analysis.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Nixon 1990

MethodsRandomized double-blind, cross-over study, single center.


Participants36 people with CF. Equal number of participants with FEV1 > 50% FVC and FEV1 < 50% FVC recruited.
Participants divided into "Low Sat" group versus "High Sat" group. Low sat group: mean age 20.8 +/- 4.5 years, 9 male and 6 female. "High Sat" group: mean age 13.9 +/- 4.1 years, 13 male and 6 female.
2 younger participants excluded from results as unable to co-operate sufficiently.


Interventions2 consecutive maximal exercise tests, FiO2 0.21 & 0.30.


OutcomesWork rate, O2 consumption, HR, SaO2, ETCO2, VE.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Low riskBoth the participants and the supervising clinician were blinded to the gas mixture received.

Blinding (performance bias and detection bias)
Clinicians
Low riskBoth the participants and the supervising clinician were blinded to the gas mixture received.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskNot mentioned.

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskAnalyzed data on participants with less than 15% exclusions; data from 2 participants not analyzed, as they were too young to co-operate sufficiently. Unclear as to whether they were from the same group, therefore unclear as to whether their withdrawal led to a risk of bias.

Selective reporting (reporting bias)Unclear riskChanges in gas exchange and exercise tolerance were reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Parsons 1996

MethodsRandomized cross-over study, single center.


Participants11 people with CF with severe lung disease age 13 to 36 years. Only 7 participants had blood gases taken prior to the first study and upon wakening after each study.


InterventionsOn 2 consecutive nights, nasal cannula delivering FiO2 0.21 & 0.30.


OutcomesTotal sleep, sleep quality and architecture, SaO2, tPCO2, respiratory events.


NotesIn-hospital PSG.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Clinicians
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskDegree of blinding not discussed.

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskNot clear if the results reported are from all 11 participants or just the 7 who had arterial blood gas measurements taken prior to the first part of the study and after each subsequent part.

Selective reporting (reporting bias)Unclear riskChanges in gas exchange and some sleep parameters were reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Shah 1997

MethodsRandomized controlled cross-over study, single center. Single blind (participants).


Participants17 people with CF, mean age 25 years, 9 male and 8 female. 17 people in control group, mean age 25 years, 10 male and 7 female. States each participant performed exercise before and after O2.


Interventions2 consecutive supramaximal exercise tests with recovery FiO2 0.21 or 0.30, then repeat exercise.


OutcomesVO2max, HR, VE, SaO2, peak work, exercise time, AT, subsequent work performance.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Low riskParticipants blinded to the type of therapy administered.

Blinding (performance bias and detection bias)
Clinicians
Unclear riskNot mentioned.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskNot mentioned.

Incomplete outcome data (attrition bias)
All outcomes
Low riskDoes not explicitly state that an intention-to-treat analysis was conducted. However, data appear to have been analyzed based on all enrolled participants; states that all participants completed all the exercises.

Selective reporting (reporting bias)Unclear riskChanges in gas exchange and exercise tolerance were reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Spier 1984

MethodsRandomized cross-over study, single center.


Participants8 people with CF, mean age 22, 5 males and 3 females, all with severe lung disease. Selected for the study if in stable clinical state and SaO2 less than 92% on random arterial blood gas.
10 participants initially recruited, 2 participants analyzed separately due to history of snoring.


InterventionsNasal cannula during sleep with FiO2 0.21 & 0.31 on 2 consecutive nights.


OutcomesMeasures of sleep quality, tPCO2 and SaO2, respiratory events.


NotesIn-hospital PSG.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Clinicians
Unclear riskDegree of blinding not discussed.

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskDegree of blinding not discussed.

Incomplete outcome data (attrition bias)
All outcomes
Low riskData analyzed on all enrolled participants. Two participants had obstructive sleep apnea symptoms and were mentioned separately but still included in the analysis.

Selective reporting (reporting bias)Unclear riskChanges in gas exchange and sleep parameters were reported in full.

Survival is not specifically mentioned but there are data for all patients at the end of the study.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

Zinman 1989

MethodsMulticenter randomized double-blind parallel controlled study.


Participants28 people with CF older than 12 years of age. Oxygen group mean age 23 +/- 6.7 years, air group mean age 22.1 +/- 4.9 years. 9 males and 5 females in each group.
All participants with FEF 25-75 < 25% predicted, and whose awake arterialized capillary PO2 < 65 mm Hg on 2 occasions.
10 patients dropped out voluntarily (4 in oxygen group). O2 group (10 completed study): dropouts 2 died during follow-up; 2 survived. Air group (8 completed study, all alive at follow-up): dropouts 4 died at follow-up; 2 survived.


InterventionsO2 therapy or room air gas at night only, titrated to increase awake PaO2 > 70 mm Hg.


OutcomesMortality, lung function, anthropometrics, RAG, psychosocial questionnaire.


NotesO2 given only during sleep, average 7 hours.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskReported that the order of interventions was randomized, but no details of the method of randomization used.

Allocation concealment (selection bias)Unclear riskNo details of allocation concealment stated.

Blinding (performance bias and detection bias)
Participants
Low riskParticipants were blinded to the gas mixture received.

Blinding (performance bias and detection bias)
Clinicians
Low riskIn hospital, oxygen therapy was at the discretion of the supervising clinician; at home the physician was obliged to "respect the blind nature of the study".

Blinding (performance bias and detection bias)
Outcome assessors
Unclear riskNot mentioned.

Incomplete outcome data (attrition bias)
All outcomes
Low riskData were analyzed both on an intention-to-treat basis and on the 18 participants who completed the study (10 dropped out - 4 from the oxygen group and 6 from the room air group).

Follow-up of all participants with respect to survival data was complete.

Selective reporting (reporting bias)Unclear riskSurvival data, changes in lung function, changes in gas exchange, quality of life, Wmax, nutritional status and changes in pulmonary artery pressure were reported in full.

Other parameters not mentioned therefore assumed not measured.

Other biasUnclear riskNo other bias mentioned.

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Elkins 2004Comparison of two modes of ventilation, not oxygen supplementation.

Fauroux 1999Comparison of chest physiotherapy with and without pressure support, not oxygen.

Fauroux 2000Comparison of aerosolisation with and without pressure support, not oxygen.

Fauroux 2001Comparison of two modes of ventilation, not oxygen supplementation.

Fauroux 2004Comparison of two modes of ventilation, not oxygen supplementation.

Holland 2003Comparison of two airway clearance techniques, not oxygen supplementation.

Placidi 2006Comparison of chest physiotherapy with and without pressure support, not oxygen.

Riethmueller 2006Comparison of rhDNAse with and without ventilation, not oxygen.

Serra 2002Study of nasal ventilation with oxygen supplementation contaminates potential impact of oxygen supplementation alone.

Stewart 2001Cycle ergometer tests using compressed air with 20 ppm NO versus compressed air only.

Young 2008Comparison of two modes of ventilation, not oxygen supplementation.

 
Comparison 1. Oxygen therapy versus control

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Survival1Odds Ratio (M-H, Fixed, 95% CI)Totals not selected

    1.1 Deaths at 36 months
1Odds Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]

 2 Change in FEV11Mean Difference (IV, Fixed, 95% CI)Totals not selected

    2.1 At 6 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    2.2 At 12 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 3 Change in FVC1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    3.1 At 6 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    3.2 At 12 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 4 Change in gas exchange during exercise5Mean Difference (IV, Fixed, 95% CI)Subtotals only

    4.1 Post exercise SaO2 (%)
384Mean Difference (IV, Fixed, 95% CI)2.11 [1.54, 2.68]

    4.2 Post exercise PETCO2 (mm Hg)
262Mean Difference (IV, Fixed, 95% CI)0.11 [-2.14, 2.36]

    4.3 Change in SaO2 during maximal exercise (%)
144Mean Difference (IV, Fixed, 95% CI)7.0 [2.61, 11.39]

    4.4 Change in PETCO2 during maximal exercise (mm Hg)
2112Mean Difference (IV, Fixed, 95% CI)3.71 [1.28, 6.14]

    4.5 Change in tPCO2 during maximal exercise (mm Hg)
144Mean Difference (IV, Fixed, 95% CI)4.0 [1.23, 6.77]

    4.6 SaO2 during maximal exercise (%)
3108Mean Difference (IV, Fixed, 95% CI)2.01 [1.16, 2.85]

 5 Change in gas exchange during sleep3Mean Difference (IV, Fixed, 95% CI)Subtotals only

    5.1 SaO2 in REM sleep (%)
234Mean Difference (IV, Fixed, 95% CI)7.54 [4.31, 10.77]

    5.2 tPCO2 in REM sleep (kPa)
112Mean Difference (IV, Fixed, 95% CI)1.0 [0.15, 1.85]

    5.3 TcPCO2 in REM sleep (mm Hg)
120Mean Difference (IV, Fixed, 95% CI)0.30 [-6.69, 7.29]

    5.4 SaO2 in non-REM sleep (%)
112Mean Difference (IV, Fixed, 95% CI)6.0 [1.92, 10.08]

    5.5 tPCO2 in non-REM sleep (kPa)
112Mean Difference (IV, Fixed, 95% CI)0.70 [-0.09, 1.49]

    5.6 TcPCO2 in non-REM sleep (mm Hg)
120Mean Difference (IV, Fixed, 95% CI)-1.0 [-6.51, 4.51]

    5.7 Maximum TcCO2 with total sleep (mm Hg)
122Mean Difference (IV, Fixed, 95% CI)5.0 [-2.07, 12.07]

 6 Change in PaO21Mean Difference (IV, Fixed, 95% CI)Totals not selected

    6.1 At 12 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 7 Change in PaCO21Mean Difference (IV, Fixed, 95% CI)Totals not selected

    7.1 At 12 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 8 Quality of life: regular attendance at school or work1Odds Ratio (M-H, Fixed, 95% CI)Totals not selected

    8.1 At 6 months
1Odds Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]

    8.2 At 12 months
1Odds Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]

 9 Sleep parameters3Mean Difference (IV, Fixed, 95% CI)Subtotals only

    9.1 Percent of total sleep time in REM sleep (%)
350Mean Difference (IV, Fixed, 95% CI)-4.49 [-6.04, -2.95]

    9.2 Percent of total sleep time in non-REM sleep
228Mean Difference (IV, Fixed, 95% CI)2.89 [-0.41, 6.20]

    9.3 Sleep latency (minutes)
112Mean Difference (IV, Fixed, 95% CI)-6.0 [-11.06, -0.94]

    9.4 Total sleep time (minutes)
228Mean Difference (IV, Fixed, 95% CI)1.93 [-30.38, 34.23]

    9.5 Arousal index
112Mean Difference (IV, Fixed, 95% CI)-2.10 [-4.28, 0.08]

 10 Exercise parameters after submaximal exercise3Mean Difference (IV, Fixed, 95% CI)Subtotals only

    10.1 Exercise duration (s)
116Mean Difference (IV, Fixed, 95% CI)163.0 [-66.91, 392.91]

    10.2 Oxygen consumption (ml/kg/min)
262Mean Difference (IV, Fixed, 95% CI)-0.43 [-2.06, 1.20]

    10.3 CO2 production (l/min)
384Mean Difference (IV, Fixed, 95% CI)-0.01 [-0.11, 0.09]

    10.4 Minute ventilation (l/min)
384Mean Difference (IV, Fixed, 95% CI)-0.92 [-3.36, 1.53]

    10.5 Heart rate (beats / min)
384Mean Difference (IV, Fixed, 95% CI)-3.96 [-8.84, 0.92]

 11 Exercise parameters during maximal exercise4Mean Difference (IV, Fixed, 95% CI)Subtotals only

    11.1 Exercise duration (min)
272Mean Difference (IV, Fixed, 95% CI)1.03 [0.11, 1.95]

    11.2 Ventilatory equivalent (VE/VO2)
3118Mean Difference (IV, Fixed, 95% CI)-3.86 [-6.82, -0.91]

    11.3 Maximum heart rate (beats / min)
4152Mean Difference (IV, Fixed, 95% CI)-1.35 [-6.05, 3.35]

    11.4 Maximum oxygen consumption (ml/kg/min)
3118Mean Difference (IV, Fixed, 95% CI)0.92 [-2.02, 3.87]

    11.5 Minute ventilation (l/min)
4152Mean Difference (IV, Fixed, 95% CI)-1.17 [-7.06, 4.73]

    11.6 Ventilatory reserve utilisation (VE/MVV)
274Mean Difference (IV, Fixed, 95% CI)-0.05 [-0.15, 0.05]

 12 Nutritional status: change in % ideal body weight for height1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    12.1 At 6 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    12.2 At 12 months
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 13 Changes in right heart function1Odds Ratio (M-H, Fixed, 95% CI)Totals not selected

    13.1 Clinical signs of cor pulmonale
1Odds Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]

    13.2 Abnormal rIght ventricular ejection fraction at rest
1Odds Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]

    13.3 Abnormal right ejection fraction with exercise
1Odds Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]

 
Table 1. Abbreviations

AbbreviationsDefinition

BiPAPbileval positive airway pressure

BMIbody mass index

CO2carbon dioxide

COPDchronic obstructive pulmonary disease

CPAPcontinuous positive airway pressure

ETCO2end tidal carbon dioxide tension

FEV1forced expiratory volume in one second

FiO2fraction of inspired oxygen, or percent of oxygen in the inspired gas

FVCforced vital capacity

kPakilopascal, a unit of air pressure

LVEFleft ventricular ejection fraction

mm Hgmillimeter of mercury, a unit of air pressure

MVVmaximal voluntary ventilation

NIPPVnon-invasive positive pressure ventilation

NREMnon-rapid eye movement

PaCO2arterial carbon dioxide tension

PaO2partial pressure of oxygen in the blood

PCO2partial pressure of carbon dioxide in the blood

PETCO2maximum partial pressure of carbon dioxide exhaled during a tidal breath, just prior to inspiration

REMrapid eye movement

RVEFright ventricular ejection fraction

SaO2saturation of haemoglobin with oxygen

SpO2pulse oximetry

TcCO2transcutaneous carbon dioxide

tPCO2transcutaneous partial pressure of carbon dioxide in the blood

VCO2carbon dioxide production

VEmean total ventilation

VO2oxygen consumption