Sedation should be avoided with spinal anaesthesia. If necessary for patient comfort, sedation should be restricted to <=40mg propofol.

 

Rationale

Delirium in elderly patients is minimized by reducing doses of sedatives and providing suitable analgesia [1].

Sedative infusions produce general anaesthesia in a significant proportion of elderly, frail, hip fracture patients, and increase the likelihood of hypotension and postoperative confusion, particularly in patients with poor preoperative cognitive function [2, 3].

This suggests that depth of anaesthesia monitoring should always be considered (and probably used) for hip fracture patients administered spinal anaesthesia with sedation [4, 5].

Oversedation may increase the risk of airway obstruction, underventilation or aspiration of gastric contents.

Spinal anaesthesia relieves the pain of a broken hip. Unsedated patients will often sleep during spinal anaesthesia as a result of disturbed sleep or opioid co-administration pre-operatively.

It should not be assumed that sedation is required for all patients with chronic cognitive dysfunction, and sedation can increase the risk of postoperative delirium and cognitive dysfunction in such patients [1].

Low-dose propofol bolus sedation may be required before turning the patient for spinal anaesthesia administration, but is not (usually) necessary if a nerve block has been administered before positioning.

Theoretically, pharmacokinetic and pharmacodynamics changes with age make propofol dosing more predictable than with midazolam, opioids or ketamine [36]

There is no evidence to support combinations of sedatives.

Sedation should be provided if specifically requested by the patient presented with this option.

This is another area where comparative research is urgently needed.

Evidence

1. Inouye SK, Westendorp RG, Saczynski JS. Delirium in elderly people. Lancet 2014; 383: 911-22.

2. Sieber FE, Gottshalk A, Zakriya KJ, Mears SC, Lee H. General anesthesia occurs frequently in elderly patients during propofol-based sedation and spinal anesthesia. Journal of Clinical Anesthesia 2010; 22: 179-83.

3. Brown CH 4th, Azman AS, Gottschalk A, Mears SC, Sieber FE. Sedation depth during spinal anesthesia and survival in elderly patients undergoing hip fracture repair. Anesthesia and Analgesia 2014; 118: 977-80.

4. Mannion S, Lee P. Bispectral index, sedation, spinal anesthesia and mortality: time to put the jigsaw puzzle together? Anesthesia and Analgesia 2014; 118: 906-8.

5. Leslie K, Short TG. Sedation depth and mortality: a large randomized trial is required. Anesthesia and Analgesia 2014; 118: 903-5.

6. Ekstein M, Gavish D, Ezri T, Weinbroum AA. Monitored anaesthesia care in the elderly: guidelines and recommendations. Drugs and Aging 2008; 25: 477-500.