Comparison of Leg Elevation and Leg Wrapping in the Prevention of Propofol Induced Hypotension

Propofol is an intravenous anaesthetic agent used for both induction and maintenance of anaesthesia. An important adverse effect is the significant fall in blood pressure. The current clinical study will be done to determine the efficacy of leg elevation and wrapping in reducing the incidence and severity of propofol induced hypotension in patients undergoing general anaesthesia.

Propofol is an intravenous anaesthetic agent used for both induction and maintenance of anaesthesia. It is widely employed due to its quick onset of action, short half life and rapid recovery. An important adverse effect is the significant fall in blood pressure. Although the exact mechanism of propofol induced hypotension is not known, venodilation, decreased peripheral resistance and decrease in cardiac output has been suggested.2 Though the hypotension is transient, it can produce devastating effects. Hence there is a need to prevent it. Moreover, several attempts at treating propofol induced hypotension have been met with variable and limited success.

Hypotension following spinal anaesthesia is also a frequent problem. It is generally treated with intravenous fluids and vasopressors. Simple and non pharmacological measures like leg elevation and leg wrapping with Esmarch bandage were reported to be successful.3 These reduce the incidence and severity of hypotension associated with spinal anaesthesia by improving the venous return.

The mechanisms of hypotension following intravenous propofol and spinal anaesthesia are almost similar. Therefore, the investigators hypothesize that leg elevation and wrapping can be attempted to reduce propofol induced hypotension. They are simple and cost effective techniques that will reduce the need for pharmacological measures to control hypotension. As the literature search did not reveal any information regarding the usefulness of these techniques in propofol induced hypotension, the current clinical study will be done to determine the efficacy of leg elevation and wrapping in reducing the incidence and severity of propofol induced hypotension in patients undergoing general anaesthesia.

The current study will compare the efficacy of leg elevation and leg wrapping in reducing the incidence and severity of propofol induced hypotension in terms of incidence of hypotension, magnitude of decrease in systolic, diastolic and mean arterial blood pressures, need for pharmacological measures to treat hypotension, changes in heart rate and adverse clinical outcomes, if any. It will be a prospective randomised controlled open label study from January 2016 to August 2017 involving 150 adult patients undergoing general anaesthesia.

For statistical analysis, descriptive statistics - minimum, maximum, mean and standard deviation will be used. Independent sample t test for data following normal distribution and for data not following normal distribution, Mann-Whitney U test will be used. P value less than 0.05 will be considered statistically significant. To study relationship between hypotension and other variables, Pearson's correlation will be used. Confidence interval will be calculated to 95%.

Eligibility Criteria:
Inclusion Criteria:

* Patients belonging to ASA physical status I and II undergoing endotracheal general anaesthesia

Exclusion Criteria:

* Patient refusal
* Contraindication to application of bandage
* Partial or complete limb amputation
* Difficult airway
* Use of extraglottic airway device
* Pregnancy
* On antihypertensive or vasoactive medication
* Autonomic neuropathy