Anaesthesia and high altitude: a history

Of Penguins, Pinnipeds, and Poisons: Anesthesia on Elephant Island

Although Ernest Shackleton's Endurance Antarctic expedition of 1914 to 1916 is a famous epic of survival, the medical achievements of the two expedition doctors have received little formal examination. Marooned on Elephant Island after the expedition ship sank, Drs. Macklin and McIlroy administered a chloroform anesthetic to crew member Perce Blackborow to amputate his frostbitten toes. As the saturated vapor pressure of chloroform at 0°C is 71.5 mmHg and the minimum alveolar concentration is 0.5% of sea-level atmospheric pressure (3.8 mmHg), it would have been feasible to induce anesthesia at a low temperature. However, given the potentially lethal hazards of a light chloroform anesthetic, an adequate and constant depth of anesthesia was essential. The pharmacokinetics of the volatile anesthetic, administered via the open-drop technique in the frigid environment, would have been unfamiliar to the occasional anesthetist. To facilitate vaporization of the chloroform, the team burned penguin skins and seal blubber under overturned lifeboats to increase the ambient temperature from -0.5° to 26.6°C. Chloroform degrades with heat to chlorine and phosgene, but buildup of these poisonous gases did not occur due to venting of the confined space by the stove chimney. The anesthetic went well, and the patient-and all the ship's crew-survived to return home.

Total intravenous anesthesia produces outcomes superior to those with combined intravenous-inhalation anesthesia for laparoscopic gynecological surgery at high altitude

Objective We compared efficacy and adverse outcomes following totally intravenous anesthesia (TIVA) versus combined intravenous-inhalation anesthesia (CIVIA) on hemodynamics and postoperative recovery following laparoscopic gynecological (LG) surgery at high altitudes. Methods We enrolled 80 ASA I or II patients scheduled for LG surgery and randomly assigned them to TIVA with propofol (group P, n = 40) or CIVIA with isoflurane (group I, n = 40). Mean arterial pressure, heart rate, pulse oxygen saturation, and partial pressure of end-tidal carbon dioxide were measured at various time points. Outcome measures were interval to spontaneous ventilation, eye opening, return to consciousness, extubation, operating room duration. Intraoperative awareness and postoperative nausea/vomiting were assessed at follow-up. Results No differences in hemodynamic parameters were detected in either group. Group P had a significantly shorter postoperative anesthetic recovery time and lower incidence of postoperative nausea/vomiting. Conclusion TIVA is superior to CIVIA for GL surgery at high altitudes.

Raymond Greene: physician, mountaineer, and raconteur

C. Raymond Greene (1901-1982) was a man of many talents. After graduating from medical school in 1927, he spent a decade in general practice. He subsequently became heavily involved in the emerging specialty of endocrinology and went on to gain considerable recognition in the treatment of thyroid disorders before eventually becoming involved in the world of medical publishing. Aside from Greene's mainstream vocational and intellectual pursuits, from boyhood he nurtured a passionate interest in mountaineering--first in his native Great Britain, and then the European Alps, and ultimately in the high Himalayas. His involvement in landmark climbs, such as the successful Kamet venture in 1931 and Everest attempt in 1933, earned him a place in the pantheon of Himalayan explorers and mountaineers and stimulated Green's interest in high altitude physiology and medicine. He made notable additions to the literature on this subject in publications such as Nature and Journal of Physiology. Apart from his remarkable life achievements in the areas of medicine, mountaineering, and publishing, Greene was perhaps best remembered by those close to him (and by contemporary readers who are devotees of his writing) as a peerless storyteller with a sardonic sense of irony.

High-altitude disorders: pulmonary hypertension: pulmonary vascular disease: the global perspective

Globally, it is estimated that > 140 million people live at a high altitude (HA), defined as > 2,500 m (8,200 ft), and that countless others sojourn to the mountains for work, travel, and sport. The distribution of exposure to HA is worldwide, including 35 million in the Andes and > 80 million in Asia, including China and central Asia. HA stress primarily is due to the hypoxia of low atmospheric pressure, but dry air, intense solar radiation, extreme cold, and exercise contribute to acute and chronic disorders. The acute disorders are acute mountain sickness (also known as soroche), HA cerebral edema, and HA pulmonary edema (HAPE). Of these, HAPE is highly correlated with acute pulmonary hypertension. The first chronic syndrome described in HA dwellers in Peru was chronic mountain sickness (Monge disease), which has a large component of relative hypoventilation and secondary erythrocytosis. The prevalence of chronic mountain sickness in HA dwellers ranges from 1.2% in native Tibetans to 5.6% in Chinese Han; 6% to 8% in male residents of La Paz, Bolivia; and 15.6% in the Andes. Subacute mountain sickness is an exaggerated pulmonary hypertensive response to HA hypoxia occurring over months, most often in infants and very young children. Chronic pulmonary hypertension with heart failure but without hypoventilation is seen in Asia. Not only does HA pulmonary hypertension exact health consequences for the millions affected, but also the mechanisms of disease relate to pulmonary hypertension associated with multiple other disorders. Genetic understanding of these disorders is in its infancy.