RESUMEN
PURPOSE OF REVIEW: Interest in the therapeutic use of mild hypothermia was rekindled in the 1980s by the publication of promising animal studies. The results of several large clinical trials have become known in the last few years. This paper examines the recent evidence supporting the use of intraoperative hypothermia for neurosurgical patients. RECENT FINDINGS: This article will cover advances made in three key areas: evidence for a clinical benefit from intraoperative hypothermia, advances in cerebral temperature monitoring, and new techniques for cooling the brain. SUMMARY: There is currently insufficient evidence to support the use of mild intraoperative hypothermia for protection against focal cerebral ischaemia. Future investigations should focus on specific patient subgroups, and make use of recent advances in selective brain hypothermia and intracranial temperature monitoring.
RESUMEN
UNLABELLED: Symptoms of orthostatic intolerance are common after general anesthesia and are associated with an increased risk of postoperative morbidity. The contribution of orthostatic hypotension (OH) has not been well defined. We conducted a head-up tilt test on patients after general anesthesia for minor surgery to assess the incidence of and risk factors for OH after general anesthesia. One-hundred-four patients were enrolled and were prospectively divided into four groups: older female, older male, young female, and young male. The incidence of OH was 76.0%, 72.0%, 45.5%, and 62.5% respectively and was associated with increasing age (P < 0.05) and posttest dizziness (P < 0.05). Body mass index, preoperative blood pressure, ASA class, anesthetic duration, IV fluid administration, and use of analgesics and antiemetics in the postanesthetic care unit were not different in subjects who demonstrated OH compared with those with a normotensive response. Subjects with OH after general anesthesia did not increase their heart rate and diastolic blood pressure with a head-up tilt which may have been caused by persistent effects of anesthetics on reflex cardiovascular control and/or bedrest-induced dysregulation of reflex cardiovascular control. We conclude that OH is common after general anesthesia for minor surgery and may be the major cause of postoperative orthostatic intolerance. IMPLICATIONS: Orthostatic hypotension, a failure to maintain blood pressure on assuming an upright posture, is common after general anesthesia for minor surgery and may be the major cause of postoperative orthostatic intolerance.