Risk of Decompression Sickness During Exposure to High Cabin Altitude After Diving

$30.00 plus tax (Refund Policy)

Buy Article:

Abstract:

Pollock NW, Natoli MJ, Gerth WA, Thalmann ED, Vann RD. Risk of decompression sickness during exposure to high cabin altitude after diving. Aviat Space Environ Med 2003; 74:1163–1168.

Background: Postdive altitude exposure increases the risk of decompression sickness (DCS). Certain training and operational situations may require U.S. Special Operations Forces (SOF) personnel to conduct high altitude parachute operations after diving. Problematically, the minimum safe preflight surface intervals (PFSI) between diving and high altitude flying are not known. Methods: There were 102 healthy, male volunteers (34 ± 10 [mean ± SD] yr of age, 84.5 ± 13.8 kg weight, 26.2 ± 4.2 kg · m−2 BMI) who completed simulated 60 fsw (feet of seawater)/60 min air dives preceding simulated 3-h flights at 25,000 ft to study DCS risk as a function of PFSI. Subjects were dry and at rest throughout. Oxygen was breathed for 30 min before and during flight in accordance with SOF protocols. Subjects were monitored for clinical signs of DCS and for venous gas emboli (VGE) using precordial Doppler ultrasound. DCS incidence was compared with Chi-squared; VGE onset time and time to maximum grade with one-way ANOVA (significance at p < 0.05). Results: Three cases of DCS occurred in 155 subject-exposures: 1/35 and 0/24 in 2 and 3 h flight-only controls, respectively; 0/23, 1/37, and 1/36 for 24, 18, and 12 h dive-PFSI-flight profiles, respectively. DCS risk did not differ between profiles (χ2 [4]=1.33; crit = 9.49). VGE were observed in 19% of flights. Neither VGE onset time nor time to max grade differed between profiles (82 ± 38 min [p = 0.88] and 100 ± 40 min [p = 0.68], respectively). Conclusion: Increased DCS risk was not detected as a result of dry, resting 60 fsw/60 min air dives conducted 24–12 h before a resting, 3-h oxygen-breathing 25,000 ft flight (following 30 min oxygen prebreathe). The current SOF-prescribed minimum PFSI of 24 h may be unnecessarily conservative.

Keywords: decompression sickness; flying after diving; high altitude; oxygen breathing; prebreathe; venous gas emboli

Document Type: Research Article

Publication date: November 1, 2003

More about this publication?
Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more