One of the popular pro-con debates at this year’s Euroanaesthesia took place during Sunday’s program, with the motion: sedation is routinely used in patients having surgery under regional anaesthesia.
Arguing for the motion was Dr Imad Awad, Staff Anesthesiologist and Assistant Professor, Sunnybrook Health Sciences Centre, University of Toronto Canada.
“Regional anesthesia provides multiple benefits to patients such as superior pain control, faster recovery, opioid sparing and reduction in potential side effects related to general anesthesia,” explained Dr Awad. “Furthermore, the benefits of regional anesthesia with regards to cardiovascular stability and protective reflexes are of interest to the caring anaesthetist. To make the experience of regional anaesthesia more acceptable to patients and to increase patient satisfaction, many steps need to be in place and one of them is conscious sedation.”
Conscious sedation could range from mild sedation (anxiolysis) to deep sedation or general anaesthesia. The most widely used agents are: midazolam 0.02-0.04 mg/kg i.v or propofol i.v continuous infusion of 25-150 mic/kg/min. Other methods of propofol delivery are: target control anesthesia (TCI), patient controlled sedation (PCS), and patient maintained sedation (PMS).
Dr Awad explained that the most widely used and practical sedation score is the modified Wilson Sedation Score. It consists of 4 variables:
- Oriented: eyes may be closed but can respond to ‘can you tell me your name?’ ‘Can you tell me where you are right now?’
- Drowsy: eyes may be closed, arousable only to command: ‘(name), please open your eyes’.
- Arousable to mild physical stimulation (earlobe tug)
- Unarousable to mild physical stimulation
Dr Awad concluded: “In summary, sedation during regional anaesthesia is easy to administer and monitor and it also enhances patients satisfaction and makes the practice of regional anaesthesia more acceptable.”
Against the motion was Dr Stephen Mannion, Consultant Anaesthetist and Chairman, Department of Anaesthesiology, Victoria University Hospital, Cork, Ireland.
He pointed out that of the 40,125 regional anaesthetic techniques without general anaesthesia that were recorded in the German Network of Regional Anaesthesia database, sedation was used in only 37.7% of them (1).
The main reasons given for administering sedation are patient comfort and anxiety reduction. “These reasons are often physician rather than patient driven,” said Dr Mannion. “In a UK survey, one third of anaesthesiologists admitted to primarily using sedation because they were not comfortable doing the nerve block (2). 82% believed patients found RA uncomfortable when evidence from patients is that about 1 in 4 only request or require it (3). A Cochrane Review from 2016 found midazolam as a sedative for procedures had little to no benefit with regard to patient anxiety or pain scores (4).”
There are many alternatives to ensure and improve patient comfort and reduce anxiety. Good communication and simple measures such as playing music in the operating theatre or via earphones have been shown to reduce anxiety levels, bispectral index values and heart rates (5,6).
Studies demonstrate that patient decision making is limited by the choice of anaesthetic technique available to them. In one study patients were 9 times more likely to choose spinal anaesthesia for hip surgery if they had previously undergone surgery under RA than GA (7).
“The use of sedation has to be balanced against the adverse effects that may arise,” said Dr Mannion. “Respiratory depression is common with an incidence from 5 – 46%, depending on the sedative drug used and patient factors such as obesity (8,9). Concerns still exist surrounding the performance of RA techniques in deeply sedated patients, in particular interscalene and thoracic epidural blocks (10).”
Finally, Dr Mannion argued that anaesthesiologists often fail to consider that patients may complain of awareness under sedation. The NAP 5 audit released in the UK found an incidence of awareness under sedation similar to general anaesthesia (1;15,000 vs 1;19,000) (11). 1/3 of all cases on the ASA Anesthesia Awareness Registry are from “failed” sedation with 78% of patients experiencing distress leading to long-term psychological consequences in 40% and post-traumatic stress disorder in 15% (12).
He concluded: “The routine use of sedation is not necessary, is not required nor requested by most patients, can cause harm and may fail to deliver on patient expectations such as amnesia and hypnosis. The performance of certain blocks under deep sedation is not recommended.”