Altitude & Anaesthesia

No abstract text is available yet for this article.

BACKGROUND: Closed loop anaesthesia delivery systems (CLADSs) are a recent advancement in accurate titration of anaesthetic drugs. They have been shown to be superior in maintaining adequate depth of anaesthesia with few fluctuations as compared with target-controlled infusion or manual titration of drug delivery. METHODS: Twenty patients scheduled to undergo general abdominal or orthopaedic procedures under general anaesthesia at Leh (3505 m above sea level) were recruited as subjects...

During an expedition to climb Everest in 1933, expedition doctor Raymond Greene administered an open-drop chloroform anaesthetic to a Tibetan patient at an altitude of more than 14,000 feet. The patient's subsequent apparent cardiopulmonary arrest has long been attributed to the effects of altitude on anaesthetic delivery. However, anaesthetics can be safely administered at a wide variety of altitudes by adequately trained and experienced anaesthetists. The problems may have arisen from an inadequate depth of anaesthesia consequent to decreased chloroform vaporisation in a cold environment, Greene's concern about potential depression of ventilation and the contemporary lack of a precise approach to assessing depth of anaesthesia...

BACKGROUND: There are few published accounts of anaesthesia delivery at high altitude. Natives at high altitude are known to have altered cardiorespiratory reserve. This study seeks to demonstrate the safety of propofol-fentanyl anaesthesia at high altitude titrated to the bispectral index (BIS) (3505 metres above sea level) in native highlanders. It also shows the differential effects of anaesthesia and surgery on the haemodynamics of such individuals as compared with individuals living at low altitude...

A 22-year-old woman presenting with postpartum haemorrhagic shock at 4243 m altitude required anaesthesia to identify and treat the source of bleeding. Slow intravenous administration of ketamine (0.5 mg x kg(-1)) resulted in deep anaesthesia and apnoea requiring hand ventilation for 5 min. Haemodynamic stability was maintained throughout the procedure. Haemostasis was achieved following uterine packing and suture of a second-degree vaginal tear and small cervical tear. Confusion and visual hallucinations occurred upon awakening but recovery was otherwise uneventful...

There is a clinical need for a safe and effective anesthetic technique in high altitude and remote areas. This report presents a series of 11 consecutive cases documenting the use of ketamine anesthesia in a remote hospital at an altitude of 3,900 m, by primary-care physicians without specialist training in anesthesia. The method of administration is fully described. At a low dose of 2.0 mg/kg, ketamine produces a dissociative anesthesia that does not depress the hypoxic drive, or interfere with the pharyngeal or laryngeal reflexes...

No abstract text is available yet for this article.

The analgesic effectiveness of 50% nitrous oxide and oxygen or oxygen-enriched air, measured by variations in pain threshold, was studied at an altitude of 1460 m and simulated altitudes of sea level and 3300 m. At sea level pressures, 50% nitrous oxide exerted a similar analgesic effect to that found for morphine, raising the pain thresholds by a mean of 71.5%. At 1460 m, the increase in pain threshold produced was 40% and at 3300 m the increase in pain threshold was only 19%. The difference between the analgesic effects of nitrous oxide at each altitude was statistically significant...

The influence that changes in altitude may have on various aspects of anesthetic practice are discussed. The consequences of alterations in the partial pressure and density of anesthetic gases are described, as well as the problems that may arise as a result of using measuring devices calibrated in percentages that actually measure partial pressure. The performance of vaporizers under conditions of reduced barometric pressure is considered. The behavior of flowmeters at altitude was studied. The increase in flow produced by flowmeters under hypobaric conditions is not a constant factor dependent on density, but is variable at flow rates below 4 L/min...