by Megan Wilson, NP-S
One of the last things anybody wants to go through is a surgical procedure, especially if you happen to be in the mountains on vacation. Unfortunately, life happens, and whether you’re a visitor to high-altitude or a permanent resident, there is a chance you may need surgical care.
Anesthesia is a requirement for surgical procedures and there are varying levels of anesthetic available. General anesthesia, often referred to as “going off to sleep”, is where you are completely unconscious and anesthetic gases and medications keep you sedated while a machine breathes for you during your procedure. Monitored anesthesia care (MAC), also known as conscious sedation, is when the anesthesiologist keeps you comfortable with meds, but you are still able to breathe on your own. Medications given for surgery affect your ability to breathe, which is why your vital signs (oxygen levels, blood pressure, heart rate) are monitored through a machine by a doctor.
How is this different at high altitude?
When you head to higher elevations, barometric pressure decreases and causes partial pressure of oxygen to decrease – this makes oxygen harder to effectively get into your lungs and causes hypoxemia/low oxygen levels (Leissner & Mahmood, 2009). This leads to a condition commonly known as altitude sickness, causing headaches and trouble breathing, and in more serious cases, it can also lead to high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). Much like oxygen, anesthetic gases are also affected by barometric pressures, impacting the effectiveness of inhaled anesthetics (Bebic et al., 2021). Additionally, equipment is affected by high altitude – meters on anesthesia machines that monitor gas/oxygen levels tend to under-read at higher elevations (Bebic et al., 2021; Leissner & Mahmood, 2009). Pulse oximetry, which measures your overall oxygen saturation (the percentage of oxygen in your blood) also has limited accuracy at high altitude (Bebic et al., 2021). Providers who practice at higher elevations should be aware of these nuances and treat accordingly. The most important treatment we have to help with the effects of partial pressure at high altitude is supplemental oxygen (Leissner & Mahmood, 2009).
Unfortunately, there is limited research on the effects of high altitude and anesthesia, and even less on the effects of anesthetic drugs at high altitude vs. sea level (Bebic et al., 2021). With current published data, it is clear that surgical risks increase with elevation. Whether it’s the potential for equipment to malfunction, or novice providers new to high-altitude unaware of the subtleties in treatment, it is critical to be mindful of compromised respiratory status at elevation when considering which anesthetic agents to use for surgery.
References
Bebic, Z., Brooks Peterson, M., & Polaner, D. M. (2021). Respiratory physiology at high altitude and considerations for pediatric patients. Pediatric Anesthesia, 32(2), 118-125.
https://doi.org/10.1111/pan.14380
Leissner, K. B., & Mahmood, F. U. (2009). Physiology and pathophysiology at high altitude:
Considerations for the anesthesiologist. Journal of Anesthesia, 23(4), 543-553.
