A survey of neuraxial analgesic preferences in open and laparoscopic major abdominal surgery amongst anaesthetists in Australia and New Zealand

Introduction

Globally, major abdominal surgery is a common procedure and is associated with significant postoperative pain, morbidity and cost. Effective postoperative analgesia is fundamental to optimal postoperative recovery. ^{1 2} To this effect, epidural analgesia continues to be recommended in recent Enhanced Recovery After Surgery (ERAS) protocols. ³ However, major clinical benefits of epidurals have not been clearly demonstrated in large randomised controlled studies, they can be difficult to insert and maintain and are not without risk. ^{4 5} We believe the place of epidurals is increasingly questioned in the setting of continuous improvement in surgical techniques, especially given the shift toward less invasive alternatives to open surgery such as laparoscopic and robotic-assisted surgery. Alternative analgesic strategies include intrathecal techniques (including intrathecal opioids), systemic analgesia and regional blocks (with local anaesthetic agents). These analgesic options avoid some complications of epidural analgesia, however, they are not themselves devoid of limitations or adverse effects. ^{6 7} Sedation, nausea, vomiting, pruritus and respiratory depression are side-effects of intrathecal opioids. Hydrophilic opioids such as morphine may cause early or late respiratory depression, with a peak at six hours following injection. Hence, patients require heightened observation for a minimum of 24 hours following intrathecal morphine. ⁸ Additionally, minimising perioperative opioid use is increasingly the focus of efforts to reduce the ‘opioid epidemic’ and abuse crisis given that long-term opioid use often begins with the treatment of acute pain. ^{9 10}

Methods

After ethics committee approval (Northern Sydney Local Health District Ethics Committee RESP/18/195-hawke) and pilot testing of the survey amongst at least 10 departmental members between two academic centres, one in New South Wales and one in Victoria, we conducted a survey designed to provide insight into current analgesic preferences amongst practising Fellows of the Australian and New Zealand College of Anaesthetists (ANZCA) when managing patients having major abdominal surgery. Major abdominal surgery was defined as surgical resection lasting >two hours. No funding was received in relation to this survey. The major knowledge gaps we set out to identify included:

Whether practising ANZCA Fellows had an analgesic preference in this patient cohort, distinguishing between open and laparoscopic surgical techniques and between surgical subtypes.

Results

Baseline demographic data of respondents, including sex, years since obtaining Fellowship, and country state and location (e.g. private/public, metropolitan/rural) of clinical practice were obtained to ensure the respondents were representative of the ANZCA general membership.

We asked anaesthetists how many elective major open and laparoscopic abdominal surgery cases they manage per week, whether they utilise neuraxial techniques when not contraindicated, and if so, their preference for epidurals or spinal anaesthesia with intrathecal opioids. Surgical subtypes were divided into upper gastrointestinal, colorectal, urological/gynaecological, vascular or other surgery and preferences for use of a neuraxial technique in each of these surgical subspecialties sought. The perceived benefit of a neuraxial techniques and utilisation of analgesic adjuncts was also sought from respondents. Using a scale from 0–100 we asked about the perceived importance of opioid-minimisation strategies in this cohort of patients. Finally, we questioned respondents about their access to an acute pain service, and whether institutions had postoperative patient disposition restrictions following the administration of intrathecal morphine.

In total, the survey was sent to 975 Fellows and 275 (28%) completed the survey. Consistent with ANZCA general membership, 67% of respondents were male. Additionally, there was an even spread of experience amongst respondents, with 21%–27% having received their Fellowship in each time period identified (<5 years, 5–10 years, 11–20 years, >20 years).

The largest group (35%) of anaesthetists manage two open major abdominal surgery case per month whereas 36% of anaesthetists manage four to eight laparoscopic major abdominal surgery cases per month.

The majority of respondents believe neuraxial techniques benefit patients through an opioid-sparing effect (91%), reduced sympathetic stress response (75%), reduced ileus (58%) and greater patient satisfaction (55%). Only 4.6% of respondents believe neuraxial techniques confer none of these benefits. Yet less than half of the respondents utilise a neuraxial technique to manage their major abdominal surgery cases and this was spread fairly evenly across upper gastrointestinal (42%), colorectal (42%) and urological/gynaecological (37%) surgical subspecialties.

Specific to open major abdominal surgery, less than half (43%) of respondents routinely use a neuraxial technique, with an even spread found between perioperative epidural use and intrathecal morphine (48% versus 49%, respectively). For laparoscopic major abdominal surgery, only a minority (16%) of respondents routinely use a neuraxial technique in these patients. In those respondents who do use a neuraxial technique, intrathecal morphine is preferred by 74% of respondents.

Multimodal analgesia is utilised by the majority of respondents across open and laparoscopic major abdominal surgery including: transversus abdominis plane blocks (43% versus 19%), intravenous lidocaine (44% versus 37%), ketamine (57% versus 37%), non-steroidal anti-inflammatories (77% versus 81%), intravenous patient-controlled analgesia (87% versus 68%) and paracetamol (96% versus 96%).

Most institutions allow for the postoperative management of epidurals (71%), as well as low dose (less than 200 μg) intrathecal morphine (76%) on the surgical ward. The majority (87%) of institutions have a pain service conducting daily ward rounds. However, only 43% of these ward rounds are led by a pain specialist, with a further 30% occasionally being led by a pain specialist or by an anaesthetist.

Finally, on a scale from 0 to 100, the importance of an opioid-minimisation strategy in major abdominal surgery was regarded as moderately important by the respondents, with a median score of 67. This was between the score of 50, referenced on the scale as ‘Somewhat important; may/may not influence my practice’ and 100, ‘Extremely important; influences my practice’.

Discussion

Strengths of our survey include representation of practising ANZCA Fellows, with a response rate that is similar to past ANZCA-delivered surveys. This provided insight into current preferences and practice patterns amongst ANZCA Fellows in regard to managing analgesia for patients having major abdominal surgery. This is informative for the design of future studies in this area of clinical practice. Additional information regarding the epidural protocols chosen and doses of intrathecal morphine administered specific to patients and surgical subspecialties would have been informative but was beyond the scope of this survey. Postoperative management of neuraxial techniques has clear implications for resource management, including affecting patient disposition, necessitating an acute pain service, management of side-effects and complications and may influence the analgesia strategy chosen by anaesthetists. ⁸

In conclusion, anaesthetists are managing patients having laparoscopic major abdominal surgery more frequently than open procedures, which is consistent with the rapidly growing number of minimally invasive procedures. Neuraxial techniques continue to be utilised, with a marginal difference between epidurals and intrathecal morphine in open surgery. A minority of anaesthetists (16%) utilise neuraxial techniques, with a strong preference towards intrathecal morphine, in laparoscopic surgery. The discordance between a strong perception of benefits derived from neuraxial techniques and the low clinical utilisation in major laparoscopic abdominal surgery is an important area that requires further investigation, especially given the need for opioid minimisation strategies.

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