What do we mean by spinal anaesthesia for ambulatory surgery? The term merely describes the targeted use of spinal anaesthesia in such a way as to take full advantage of its many benefits in the day case setting, whilst minimising the side effects associated with more traditional approaches.
In the UK, spinal anaesthesia (SA), and regional anaesthesia (RA) in general, have historically been regarded with some suspicion by the anaesthetic profession. Prior to the 1950s, SA was in widespread use but serious complications in two consecutive patients (Woolley and Roe,1) at a time when training, governance, new drugs and monitoring in general anaesthesia had all been recently improved led to a decrease in popularity. We are fortunate that mainland Europe and Scandinavia were not thus affected and continued to develop and promote RA and SA, although this has by no means been universal.
Epidural and SA have developed and increased in popularity in the in-patient population specifically in obstetrics and major joint arthroplasty over the last 30 years but traditionally the “quick GA” has been the option for most other procedures; SA was rarely offered as a choice, particularly in the ambulatory setting.
It is often claimed that patients, surgeons and day surgery staff don’t like SA for the reasons of timing, slow recovery of function and urinary retention. The other claim that “patients don’t like being awake” is possibly our fault as anaesthetists in failing to promote RA as an option over the last 50 years, influencing a number of generations of patients, surgeons and our trainees. Indeed those with a RA interest understand that once patients have tried it the majority will request it in the future. Less paternalism in medicine and surgery along with increased patient education and exposure in the media have all been instrumental in reducing the mystique.
JFK said ‘In a crisis, be aware of the danger-but recognise the opportunity’(2). The usage and interest in RA and SA have been great opportunities during COVID-19 for patients, staff and anaesthetists alike, presenting us with an alternative to the risks of GA. Discussion is on-going with respect to the dangers of Aerosol Generating Procedures (AGP) and the relative timings and importance of airway intervention techniques in their production. A particular concern remains with PACU/anaesthesia recovery staff who are possibly more vulnerable than most to the uncooperative, unprotected airway. Patients, probably sensibly, are regarding hospitals as less “hotels for convalescence” and more day units where they have their procedure and leave for the safety and comfort of home.
Fig 1 «Once the advantages of shorter acting SA techniques have been appreciated along with increasing experience and familiarity they may well be offered increasingly to patients as a routine option in the post COVID-19 era.»
The recent interest in RA in the wider anaesthetic world raises questions of training and competence which are being addressed by some new initiatives (3) but it is important to employ caution as enthusiasm can sometimes race ahead of ability. It remains that, whatever the anaesthetists competence in RA, SA is very much the RA that all anaesthetists are competent to perform.
Bupivacaine is a reliable and effective agent and has been the drug of choice for SA for 50 years. In hyperbaric form it is licenced for use as Marcain Heavy 0.5% in the UK, however whereas it’s isobaric (plain) preparation, although widely used, is not licenced Levobupivacaine is licenced for intrathecal use. The long acting nature of bupivacaine has not enhanced the reputation of SA in the ambulatory setting or indeed for in-patient surgery of under 90 minutes. Lidocaine was used extensively for shorter procedures prior to the 1990s when concerns over transient neurological syndrome caused it to be withdrawn for SA. Newly packaged “old” local anaesthetics Prilocaine and 2-chloroprocaine have been introduced in Europe in the last 10 years and are enjoying increased popularity.
Hyperbaric prilocaine 2% has been available for over 10 years in Europe and can be used for any surgical procedure lasting up to 90 minutes where SA is considered appropriate and Bupivacaine was previously the only option. Up to 120 minutes is possible for lower dermatomal procedures. Its baricity allows manipulation of block level by dose and patient positioning; 0.5ml(10mg) being adequate for a perineal block and 3ml(60mg) for periumbilical procedures. 2-chloroprocaine 1% is licenced in Europe for 40 minutes of surgical time although procedures of 70-80 minutes may be achieved if knee or foot/ankle procedures are planned. By targeting the anaesthetic to suit the length of surgery these agents are increasingly being used for non day-case procedures to maximise the benefits of SA whilst addressing the issues of urinary retention, delayed mobilisation and patient satisfaction.
Enhanced recovery regimes for major arthroplasty have employed “low-dose” spinal bupivacaine, often with added opioid, over a number of years in an attempt to overcome the limitations of a long acting agent (4). Failure of adequate block and side effects such as urinary retention are still common and, as such, heavy sedation is often used to compensate for inadequate anaesthesia. As arthroplasty surgery evolves down the day case route the use of “normal dose” prilocaine and 2-chloroprocaine is becoming increasingly common to achieve adequate analgesia for surgery whilst allowing rapid recovery without the unwanted side effects. Traditionally the anaesthetist might allow a patient to return to the ward assuming them to be pain free due to persistent spinal block, only for it to wear off later in the evening where they are “out of sight, out of mind”. Clearly a more rapid offset of spinal block results in the need to appreciate the increasing importance of quality multimodal analgesic regimes including motor sparing RA techniques as part of the package and the need to optimise analgesia prior to discharge from PACU. This is generally an approach to be encouraged whatever the mode of anaesthesia.
Data from Guys and St Thomas’ Hospital in London during the COVID pandemic has demonstrated a rise in emergency surgical procedures performed under RA as the sole technique from 11% in the corresponding period in 2019 to 26% in the peak of the crisis (5). Procedures such as perianal abcess drainage, hernia surgery, ERPC, the majority of lower limb trauma surgery and many more can be achieved with the exclusive use of the newer spinal agents allowing a rapid recovery and discharge.
Fig 2 «Decision making is best left to each independent practitioner but in order to guide the practical process of choosing which drug to target to each procedure I have developed a pragmatic flowchart.»
The availabilty of reliable, short-acting spinal agents during the COVID-19 pandemic as an alternative for procedures traditionally performed with general anaesthesia has been timely. Once the advantages of shorter acting SA techniques have been appreciated along with increasing experience and familiarity they may well be offered increasingly to patients as a routine option in the post COVID-19 era (Fig1).
I have made a few suggestions as to which spinals and doses may be used for particular procedures, however it is not possible or practical to be comprehensive and over-prescriptive. Decision making is best left to each independent practitioner but in order to guide the practical process of choosing which drug to target to each procedure I have developed a pragmatic flowchart (Fig 2),(6) which asks three simple questions in each chosen case. Whilst being in no means comprehensive it has served as a useful aid to help new users to choose correctly. The guide is aimed at ambulatory surgery but can act as a guide for any procedure including, for example, ambulatory lower limb arthroplasty or hip fracture anaesthesia.
Many RA practitioners have embraced the increase in interest in their field with the advent of USGRA over the last 15 years as well as the enthusiasm for the development of new targeted approaches, increased success rates and improvement in safety that it has brought. SA is sometimes forgotten in the excitement but is, and will remain, the most commonly performed single RA technique in the world. New spinal anaesthetic approaches will only increase its popularity both in the present pandemic and beyond, and together with RA are already contributing to reduced hospital stay and a better patient experience.
1. JR Maltby, CDD Hutter and KC Clayton The Woolley and Roe case British Journal of Anaesthesia 84 (1): 121-6 2000
2. John F Kennedy Indianapolis speech April 12 1959
3. LR Turbitt, ER Mariano, K El-Boghdadly Future directions in regional anaesthesia: not just for the cognoscenti Editorial Anaesthesia 75 (3) 2019
4. B Ben-David, E Solomon, H Levin et al. Intrathecal fentanyl with small-dose dilute bupivacaine: better anaesthesia without prolonging recovery Anaesth Analg 85(3): 560-5 1997
5. S Wade, G Nair, HA Ayeni et al. A cohort study of emergency caseload and regional anesthesia provision at a tertiary UK hospital during the initial COVID-19 pandemic Cureus 12(6): e8781. DOI 10.7759/cureus.8781 June 23 2020
6. W Rattenberry, A Hertling, R Erskine Spinal anaesthesia for ambulatory surgery BJA Education 19(10), 321-328, 2019
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