Acute mountain sickness score and hypoxemia.

Abstract

BACKGROUND:

Hypoxemia is the immediate consequence of hyobaric hypoxia, which is the crucial starting mechanism of acute mountain sickness (AMS). The AMS is generally a benign and self-limiting condition which can be prevented by gradual ascent. However, ascent rates recommended for prophylaxis of AMS are far slower than those attempted during military operations and by climbers.

OBJECTIVE:

The current study was carried out to quantify the relationship between AMS and hypoxemia alongwith evaluating the benefits of acetazolamide-dexamethasone chemoprophylaxis during acute ascent.

SUBJECTS AND METHODS:

Twenty-four low lander male adults (age mean +/- SE 27.8 +/- 1.24 years) were selected. They were grouped in a double-blind fashion into four groups and each group (n = 6) received placebo (multivitamin) or acetazolamide (250 mg) or dexamethasone (4 mg) or a combined regimen of the two drugs twice daily for 5 days, commencing 24 hours before ascent. The volunteers reached the altitude of 4578 meters within a span of one day. Their AMS symptoms were recorded on modified environmental symptoms questionnaire (ESQ), after 24 and 72 hours of ascent. Arterial PO2, SO2 and PCO2 were measured by GEMSTAT blood-gas analyzer (Mallincrodt-USA).

RESULTS:

The ESQ, AMS-C (cerebral) and AMS-R (respiratory) scores of combined therapy group were significantly lower as compared to the other groups on the symptom rating scale. The significant finding amongst the volunteers taking acetazolamide was mild to moderate diuresis whereas severity of headache was markedly less in dexamethasone group. The commonest feature of combined therapy was that none of the volunteers complained of headache, dysponea, irritability and more than mild disturbance of sleep. The ESQ scores of volunteers were inversely correlated to PaO2 and SaO2 after 24 hours of ascent to 4578 meters.

CONCLUSION:

The study concludes that severity of AMS is closely related to hypoxemia and combination therapy of acetazolamide-dexamethasone may be effective in preventing AMS.

• Authors: M M Hussain, M Aslam, Z Khan
• Journal: JPMA. The Journal of the Pakistan Medical Association (J Pak Med Assoc) Vol. 51 Issue 5 Pg. 173-9 (May 2001) ISSN: 0030-9982 [Print] Pakistan
• PMID: 11467238 (Publication Type: Clinical Trial, Comparative Study, Journal Article, Randomized Controlled Trial)

Chemical References

• Dexamethasone
• Acetazolamide

Topics

• Acetazolamide (adverse effects, therapeutic use)
• Acute Disease
• Adult
• Altitude Sickness (diagnosis, drug therapy)
• Developing Countries
• Dexamethasone (adverse effects, therapeutic use)
• Double-Blind Method
• Drug Therapy, Combination
• Humans
• Hypoxia (diagnosis, drug therapy)
• Male
• Pakistan