Patients' expectations, experience and acceptability of postoperative analgesia: a nested qualitative study within a randomised controlled trial comparing rectus sheath catheter and thoracic epidural analgesia

Adequate postoperative analgesia is a key element of enhanced recovery programmes. Thoracic epidural analgesia is associated with superior postoperative analgesia but can lead to complications. Rectus sheath catheter analgesia may provide an alternative. In a nested qualitative study (within a two‐year randomised controlled trial) focussing on the acceptability, expectations and experiences of receiving the interventions, participants (n = 20) were interviewed 4 weeks post‐intervention using a grounded theory approach. Constant comparative analysis, with patient and public involvement, enabled emerging findings to be pursued through subsequent data collection. We found no notable differences regarding postoperative acceptability or the experience of pain management. Pre‐operatively, however, thoracic epidural analgesia was a source of anticipatory fear and anxiety. Both interventions resulted in some experienced adverse events (proportionately more with thoracic epidural analgesia). Participants had negative experiences of the insertion of thoracic epidural analgesia; others receiving the rectus sheath catheter lacked confidence in staff members' ability to manage the local anaesthetic infusion pump. The anticipation of the technique of thoracic epidural analgesia, and concerns about its impact on mobility, represented an additional, unpleasant experience for patients already managing an illness experience, anticipating a life‐changing operation and dealing with concerns about the future. The anticipation of rectus sheath catheter analgesia was not associated with such anxieties. Patients' experiences start far earlier than the experience of the intervention itself through anticipatory anxieties and fears about receiving a technique and its potential implications. Complex pain packages can take on greater meaning than their actual efficacy in relieving postoperative pain. Future research into patient acceptability and experience should not focus solely on efficacy of pain relief but should include anticipatory fears, anxieties and experiences.


Introduction
Adequate postoperative analgesia is a key element of enhanced recovery programmes which include regional anaesthesia for stress response reduction, optimal pain relief and early enteral nutrition and mobilisation [1][2][3].
Thoracic epidural analgesia is the standard postoperative analgesia following major surgery within enhanced recovery programmes, given its superiority as a postoperative analgesic and reduced adverse events, when compared with high-dose systemic opiates, and its association with a reduction in the stress response to surgical injury [4][5][6]. Notwithstanding, it may be accompanied by complications (e.g. nerve injury and epidural haematoma) and adverse effects (e.g. motor blockade of lower limbs and urinary retention) [5][6][7][8][9].
Hypotension is common and may result in fluid overload, impeding recovery and mobility and increasing hospital stay [10,11] and`failed´epidural analgesia is relatively frequent (20-32% in thoracic epidurals) [12,13]. As such, there remains controversy about thoracic epidural analgesia providing the best quality postoperative analgesia [14].
Rectus sheath catheters are a regional anaesthetic technique administered into the space between the rectus muscle and the posterior rectus sheath [15]. First described in the 19th century [16], its reliance on tactile sensations was associated with needle misplacement and complications such as insufficient block and visceral or vascular injury [17].
Recently, the use of ultrasound for needle placement, small calibre infusion catheters and long-acting local anaesthetics has led to renewed interest in rectus sheath catheter analgesia for postoperative pain following midline abdominal incisions [15,18].
In this study, which adheres to the consolidated criteria for reporting qualitative research (COREQ [19,20] from EQUATOR), we present the results of a patient-focused nested qualitative study, within a randomised controlled trial, which aimed to assess efficacy, safety and acceptability to patients of rectus sheath catheter analgesia compared with thoracic epidural analgesia [21]. With these types of complex pain packages, efficacy is not simply about providing the lowest subjectively assessed pain intensity scores, but should also take into account of ease of mobility; respiratory function; adverse events; morbidity; failure rate; staff compliance with administration; and, most importantly, patient acceptability and experience. This study focused on exploring patients' experiences, expectations and acceptability of receiving rectus sheath catheter or thoracic epidural analgesia following laparotomy.

Methods
A cross-sectional qualitative study utilising an inductive approach informed by the principles of constructivist grounded theory [22] took place at the Royal Blackburn Teaching Hospital, a large district general teaching hospital in England.
Participants were all adult patients (aged 18 y or over) who were listed for elective major abdominal surgery via a midline incision within an enhanced recovery pathway.
Eligibility criteria included: no contraindications to epidural analgesia; no allergies to anaesthetic drugs or opiates; no opiate tolerance (defined as any patient on pre-existing opiates); no issues with chronic abdominal pain or extensive existing midline abdominal scarring; and consent to participate in the randomised controlled trial (and be randomised to either group) as well as consent for the qualitative study [15,21]. Written informed consent was received from all participants and ethical approval was obtained.
The interventions comprised: rectus sheath catheter, using an amBIT rectus sheath catheter pump (Avanos, Cardiff, UK) [23] set to deliver a 40 ml bolus of ropivacaine 0.2% (over 20 min) with a 4 h lockout. Despite extensive pre-operative education, no patients were capable of self-administering and all doses were staff administered. Newer generation pumps have auto-bolus capability, obviating reliance on patient or staff compliance; and epidural, using a Hospira GemStar infusion system (Hospira, Maidenhead, UK) [24], with most patients receiving a bolus of 10 ml bupivacaine 0.25% with 100 lg fentanyl. Full details about the interventions, including assessment of blocks and another analgesia, can be found in the protocol and trial manuscript [15,21].
We followed the principles of constructivist grounded theory, which engages with multiple perspectives to develop an understanding of research problems about which little is known. A constructivist grounded theory approach seeks to understand a problem by asking probing questions of the data about what is happening [25]. The resulting explanation (theory) is generated as the research progresses; and data collection and analysis takes place concurrently [26], enabling the explanatory theory to be developed and refined both through future data collection and sampling (known as theoretical sampling) [27].
Immediately after each interview, the researcher compiles fieldnotes (thoughts and observations, including selfreflective elements), which contribute to descriptive and theoretical memos. In this study, convenience sampling was used initially, followed by theoretical sampling, and we sought equal proportions from both groups and to mirror the trial population [21] in terms of sex and age. rigour [29]. The resulting codes and tentative themes were applied to the coding and interpretation being undertaken by the research team and contributed to subsequent theoretical sampling and the focus of data collection, which continued until data saturation was achieved.

Results
Twenty participants were interviewed (n = 10 rectus sheath catheter analgesia, n = 10 thoracic epidural analgesia), 70% (n = 14) were men, all identified as white British. The mean (SD) age was 67.7 (8.9) y for the rectus sheath catheter cohort and 64.5 (10.2) y for the thoracic epidural group. All participants came to the randomised controlled trial following a recent, and for the majority, unexpected diagnosis of cancer (n = 17) ( Table 1).
Three patient-oriented themes were identified: The discomfort also extended to the room in which the thoracic epidural analgesia was inserted, which was

Discussion
Our data enabled us to identify differences and commonalities about perceived effectiveness, acceptability and patient expectation from the perspectives of patients.
We found no notable differences in terms of perceived effectiveness for postoperative pain. Similarly, some experiences of lack of effectiveness were identified in both groups. More adverse events were reported with thoracic epidural analgesia; although our data do not seek to be quantifiable, we found over a third reported having experienced some of the typical adverse events. This mirrored the findings in the randomised controlled trial, where serious adverse events were three times greater in the epidural group [21]. Only one of our rectus sheath participants reported side effects (nausea), which they ascribed to the analgesic. The presence of pre-operative negative anticipation is an important finding in research into analgesic interventions given associations between pain anticipation and pain [36].
We found that negative anticipation initiates in the time before the patient receives the intervention and experiences pain relief. Anxiety was not mitigated even when participants were confident that the epidural would provide pain relief, Our identification of a pre-operative anticipatory phase adds to current knowledge about how expectancies of pain can modulate pain perception [39]. The need for clinicians to access unexpressed patient issues and agendas about pain is not new [40], and this research highlights the importance of anaesthetists taking a holistic view of the acceptability of a postoperative analgesic, seeing it as a complex pain package and considering pre-operative and postoperative fears and expectations.
Our study does have limitations. We could only include participants who consented to take part, those who did not wish to talk about their experiences were not represented.
The timing of the interviews could have impacted recall and earlier data collection might have illuminated anticipation.
Including people who had experienced the surgical intervention and thoracic epidural analgesia in planning, developing questions, managing and analysing the data enabled an authentic bottom-up approach to the research.
Rigour was sought through researcher reflexivity, detailed field notes and a team approach to data analysis (including people beyond the immediate research team).
In conclusion, there was no evidence that participants experienced better or worse pain management with either of the interventions, and both resulted in some adverse events (although proportionately more with thoracic epidural analgesia). There were no notable differences in terms of acceptability postoperatively, but thoracic epidural analgesia was found to be less acceptable during the preoperative phase where it added to anxieties and fears.