Risks and benefits of deliberate hypotension in anaesthesia: a systematic review.

This systematic review was performed to investigate and review the evidence on the risks and benefits of hypotensive anaesthesia in order to answer the following question: 'Should deliberate hypotension be used routinely during orthognathic surgery?' An electronic search on MEDLINE and the Cochrane Library database was carried out for all relevant articles using specific search keywords. All articles were classified by their levels of evidence. Studies with highest level of evidence and rated to have the lowest risk of bias were reviewed. Regarding the benefits of hypotensive anaesthesia, three studies reported significant decrease of blood loss in patients receiving hypotensive anaesthesia. Two studies reported a significant decrease in transfusion rate. Two studies demonstrated improved surgical field and significant reduction in operation time. In terms of risk, no significant changes in cerebral, cardiovascular, renal and hepatic functions in patients receiving hypotensive anaesthesia compared to control were reported. In conclusion, hypotensive anaesthesia appears to be effective in reducing blood loss. Serious consequences due to organ hypoperfusion are uncommon. Hypotensive anaesthesia can be justified as a routine procedure for orthognathic surgery especially bimaxillary osteotomy. Patient selection and appropriate monitoring are mandatory for this technique to be carried out safely.