Increasing numbers of patients are undergoing surgical procedures on a day stay basis. The complexity of patients encountered as “day cases” is also increasing, with increasing numbers affected by respiratory and cardiovascular disease. The use of spinal anaesthesia may provide optimal anaesthetic and surgical conditions, particularly for clinically frail or morbidly obese patients. Spinal anaesthesia also provides added advantages. It provides patients with an added choice of their anaesthetic, reduced postoperative nausea and vomiting (PONV), improved pain management and reduced cost. These advantages are of particular relevance in the day surgery unit (DSU). However, potential concerns regarding an excessively long duration of surgery / anaesthesia, or complications such as post-operative urinary retention (POUR) and post-dural puncture headache, may limit its usage.

The use of short acting local anaesthetic agents for spinal anaesthesia may facilitate greater use of regional anaesthesia for short surgical procedures, whilst minimising post-operative recovery times.

The guideline aims to provide a structure for the use of chloroprocaine and prilocaine for short surgical procedure in Frimley Health NHS Foundation Trust.

Chloroprocaine is an ester-type local anaesthetic, which blocks the generation and conduction of nerve impulses. Chloroprocaine 1% is for the intrathecal route. The typical dose is 40-50mg for motor and sensory block up to T10-12. It has a rapid onset time of
3-5 minutes and is licensed for surgical procedures up to 40 minutes, though a surgical block may last in excess of 60 minutes. A saddle block may be difficult to achieve as the solution is isobaric.

Prilocaine is a secondary amine local anaesthetic, which blocks the generation and conduction of impulses. Prilocaine 2% (Prilotekal) is for the intrathecal route. The typical dose ranges are 40-60mg for lower extremity or lower abdominal procedures lasting up to 90 minutes, and 10mg for minor perianal procedures. A typical time to discharge may be within approximately 4 hours. Prilocaine is relatively contraindicated in patients with sickle cell disease due to the risk of methaemoglobinaemia. However, typical intrathecal doses are far less than those that produce clinically apparent methaemoglobinaemia in healthy adults (typically 6mg/kg).

The following flow chart may provide a pragmatic guide to choosing a suitable intrathecal agent for typical day stay procedures:

4.1 Exclude contraindications for regional anaesthesia or agents including allergy and sickle cell disease (relative contraindication to the use of prilocaine).

4.2 Obtain informed consent for intrathecal anaesthesia as standard.

4.3 Consider likely duration of surgery and required block height in order to select intrathecal agent and dose. (See flowchart on previous page).

4.4 Intrathecal opioids are not routinely recommended in this guideline due to the potential for increased side effects such as urinary retention, post-operative nausea and vomiting and respiratory depression. However, the use of 10-25 micrograms of intrathecal fentanyl could be considered if block quality enhancement were judged to be of greatest clinical necessity.

4.5 The planned use and type of spinal anaesthetic should be clearly discussed at team brief: in particular the preserved motor tone associated with a saddle block may require some alteration in surgical technique.

5.1 Adhere to the trust WHO Surgical Safety Checklist.

5.2 Standard monitoring as per AAGBI guidelines, including BP, continuous ECG and Oxygen Saturation.

5.3 Intravenous access plus full aseptic precautions as standard including hat, mask, gown, sterile gloves and the use of 0.5% chlorhexidine as skin preparation.

5.4 Injection of spinal anaesthetic drugs as standard. Use of 25 - 27g Sprotte needles to be considered as theoretically lower risk of PDPH.

5.5 Consideration of the use of adjuvant sedative or analgesic agents at anaesthetist’s discretion.

5.6 Should the block fail to achieve the required surgical height, consider repeat spinal anaesthesia vs conversion to GA.

5.7 Avoid over-distension of bladder by limiting intravenous fluids to 500ml maximum where possible.

6.1 Handover to recovery staff in PACU as standard and complete the Trust’s post operative care pathway for patients following spinal anaesthesia observation Epi flowsheet.

6.2 After the return of normal motor and sensory function, patients should initially mobilise under direct supervision. The ability of a patient to straight leg raise against resistance provides a pragmatic indication that a safe level of motor power for mobilisation is likely to have returned.

6.3 All patients must have voided urine prior to discharge to prevent unplanned admissions due to urinary retention.

6.4 If a “high risk” patient (age >70, hernia/urological surgery, spinal opioids, previous history of prostate problems) has not voided bladder within 4 hours post procedure, a bladder scan should be performed. Urinary catheterisation should be undertaken should the bladder volume exceed 600ml (see Appendix 1).

6.5 Cases of post-operative urinary retention should undergo bladder scan and be catheterised under the care of the relevant surgical team should the bladder volume exceed 600ml. If otherwise well, patients could be discharged with catheter and return for trial without catheter (TWOC) the following day. In some circumstances, when TWOC services can’t be easily accessed, the patient will have to be admitted for an overnight stay and TWOC performed the following morning. The regional fellow should be informed of any cases of POUR for audit purposes (Appendix 1).

6.6 Patients should be educated as to whom they should contact should they suffer a complication of spinal anaesthesia such as post-dural puncture headache, post-operative urinary retention, or suspected nerve injury. They should receive a copy of the Spinal Anaesthesia for Day Surgery leaflet detailing this on discharge.

6.7 The initial point of contact for any complications in normal working hours will be the day stay unit. Out of hours, patients with an urgent complication post day surgery should present via the Emergency Department and be referred to the relevant on call teams.

6.8 Cases of suspected post-dural puncture headache should be managed as per Trust guideline “Dural puncture and post-dural puncture headache”. The starred anaesthetic consultant will coordinate management, but the patient may require admission under their responsible surgical team in order to facilitate their ongoing care.

6.9 If neurological injury post spinal anaesthesia is suspected, please refer to the Trust’s post operative care pathway following spinal anaesthesia observation flowsheet in Epic.

6.10 Patients with red flag symptoms such as progressive weakness or severe back pain should be admitted urgently via the Emergency Department. The relevant teams plus the starred anaesthetic consultant should be informed.

1. Manassero, A. and Fanelli, A. (2017) 'Prilocaine hydrochloride 2% hyperbaric solution for intrathecal injection: a clinical review', Local and Regional Anesthesia, 10, pp. 15-24. Available at: https://doi.org/10.2147/lra.s112756

2. Bjerregaard, L.S. et al. (2015) 'Incidence of and risk factors for postoperative urinary retention in fast-track hip and knee arthroplasty', Acta Orthopaedica, 86(2), pp. 183-188. Available at: https://doi.org/10.3109%2F17453674.2014.972262

3. Rattenberry, W. et al. (2019) 'Spinal anaesthesia for ambulatory surgery', BJA Education, 19(10), pp. 321-328. Available at: https://doi.org/10.1016/j.bjae.2019.06.001

4. B.Braun Medical (2023) Ampres 10 mg/ml solution for injection - summary of product characteristics. Available at: https://www.medicines.org.uk/emc/product/15158/smpc (Accessed: 28 May 2024).

5. B.Braun Medical (2023) Prilotekal 20mg/ml solution for injection - summary of product characteristics. Available at: https://www.medicines.org.uk/emc/product/15160/smpc (Accessed: 28 May 2024).

This guideline has been registered with the trust. However, clinical guidelines are guidelines only. The interpretation and application of clinical guidelines will remain the responsibility of the individual clinician. If in doubt, contact a senior colleague or expert. Caution is advised when using guidelines after the review date.
This guideline is for use in Frimley Health Trust hospitals only. Any use outside this location will not be supported by the Trust and will be at the risk of the individual using it.

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