Potential Anesthesia Protocols for Space Exploration Missions

Abstract

In spaceflight beyond low Earth's orbit, medical conditions requiring surgery are of a high level of concern because of their potential impact on crew health and mission success. Whereas surgical techniques have been thoroughly studied in spaceflight analogues, the research focusing on anesthesia is limited. To provide safe anesthesia during an exploration mission will be a highly challenging task. The research objective is thus to describe specific anesthesia procedures enabling treatment of pre-identified surgical conditions. Among the medical conditions considered by the NASA Human Research Program Exploration Medical Capability element, those potentially necessitating anesthesia techniques have been identified. The most appropriate procedure for each condition is thoroughly discussed. The substantial cost of training time necessary to implement regional anesthesia is pointed out. Within general anesthetics, ketamine combines the unique advantages of preservation of cardiovascular stability, the protective airway reflexes, and spontaneous ventilation. Ketamine side effects have for decades tempered enthusiasm for its use, but recent developments in mitigation means broadened its indications. The extensive experience gathered in remote environments, with minimal equipment and occasionally by insufficiently trained care providers, confirms its high degree of safety. Two ketamine-based anesthesia protocols are described with their corresponding indications. They have been designed taking into account the physiological changes occurring in microgravity and the specific constraints of exploration missions. This investigation could not only improve surgical care during long-duration spaceflights, but may find a number of terrestrial applications in isolated or austere environments.

Airway management in microgravity: A systematic review

“…The purpose of this literature review was to summarize the current level of evidence on airway management under space‐like conditions. Several publications exist about anesthetic concerns during spaceflight, but according to our findings, only three studies present valid data on the subject at hand. Additionally, comparing data is often complicated by inhomogeneous endpoints for airway management studies …”

“…Silverman and McCartney support the use of regional anesthesia, but indications are mostly limited to limb injuries, training requirements are high and the failure rate ought not to be underestimated in practice. Specific sedation and GA protocols have been suggested for spaceflight . A pilot study suggested that unassisted personnel with minimal medical training may be able to perform a GA with intubation during a Mars mission …”

Intubation after rapid sequence induction performed by non-medical personnel during space exploration missions: a simulation pilot study in a Mars analogue environment

“…After restoration of correct haemodynamics, the induction regimen was based on the sequential administration of atropine (1 mg), ketamine (150 mg), rocuronium (100 mg) and midazolam (2.5 mg). This rapid sequence induction protocol is considered the most appropriate for deconditioned astronauts [20]. Endotracheal intubation with an optical larynoscope (Airtraq ® ) was chosen over the conventional Macintosh laryngoscope, because it is associated with higher intubation success rates and shorter intubation times, especially in untrained hands [21, 22].…”

Emergency medicine in space

“…For space exploration missions, specific ketamine-based general anaesthesia protocols have been proposed [22]. However, delivering anaesthesia in space-and particularly during an interplanetary mission-will be a highly challenging task, even when using ketamine [23].…”