The importance of interrupting angiotensin converting enzyme inhibitor treatment before spinal anaesthesia--a controlled case report.

It is generally believed that in hypertensive patients both beta adrenoreceptor antagonists and calcium channel blockers can be continued up to the day of surgery without provoking problems with cardiovascular stability intra- and postoperatively. The same, however, has not been definitively established for angiotension converting enzyme inhibitors (ACEIs). A patient who was taking the ACAI enalapril for hypertension underwent two similar operations--right total hip replacement and three years later left--both with spinal anaesthesia. In the initial case, she received her enalapril on the morning of surgery, while for the second procedure, enalapril was stopped 48 hours earlier. Hypotension occurred which required more than 5 times the dose of etilefrin to maintain suitable blood pressure during the first instance as compared to that when enalapril had been discontinued 48 hours earlier. Spinal anaesthesia in conjunction with an ACEI may result in severe hypotension as seen in this patient. In view of this, it is suggested that in contrast to other antihypertenisve drugs, ACEIs should be withdrawn well in advance of spinal anaesthesia.