Altitude Pre-Acclimatization with an Erythropoiesis-Stimulating Agent

Abstract

Introduction: High altitude illness is a complication of rapid ascent above 2,500 m elevation. Ventilatory, circulatory and haematological adjustments, known as acclimatization, occur to maintain adequate delivery of oxygen. Although (non-)pharmaceutical strategies that modulate ventilation and circulation have long been accepted, the haematological approach has not.

Case description: This report describes the application of a comprehensive strategy, including prior pre-acclimatization using an erythropoiesis-stimulating agent (ESA), in two healthy subjects ascending from sea level to 6,268 m. Following ESA administration 30 days prior to ascent, the subjects had a cumulative haemoglobin rise of 7.1% and 11.9%, respectively. Both subjects experienced minimal symptoms during four incremental ascents to the final altitude and no adverse events occurred.

Discussion: This report has limited external validity, lacking both a sample size and controls, but can serve as practical exploration of the concept. Administration of an ESA may be a safe and useful pre-acclimatization strategy but cannot be recommended based on current evidence. More comprehensive research is needed.

Learning points: High altitude illness (HAI) is a debilitating syndrome with potentially lethal consequences caused by ascent to a hypobaric atmosphere without acclimatization.Pharmacological strategies aimed at increasing oxygen delivery may be used to prevent and treat HAI.Administration of an erythropoiesis-stimulating agent may be a safe and useful pre-acclimatization strategy but cannot be recommended based on current evidence alone.

Keywords: High altitude illness; acclimatization; erythropoiesis-stimulating agent.

Figure 1

Formula for tissue oxygen delivery. Circulatory component is in red, haematological component is in purple, and ventilator component is in blue.

Figure 2

Outcome variables of subjects at incremental altitudes during ascent. The pulse and SpO₂ of subject 2 on the Chimborazo summit could not be measured as the saturation meter’s screen froze and was subsequently unusable. Stay at a summit never exceeded 15 minutes and was amidst physical exercise, whereas basecamp stay was 8 hours at a minimum and during rest. The horizontal dotted line in the LLS graph represents an LLS of 8, an immediate descent criterion. Altitude is in meters and heart rate is in beats per minute. B, basecamp; LLS, Lake Louise Score; S, summit; SpO₂, peripheral oxygen saturation.