REG NASA-LLIS-0483-1996 Lessons Learned - Free Dive Hazard.pdf

1、Lessons Learned Entry: 0483Lesson Info:a71 Lesson Number: 0483a71 Lesson Date: 1996-12-12a71 Submitting Organization: JSCa71 Submitted by: L. UnderwoodSubject: Free Dive Hazard Description of Driving Event: During a swimming skills test at an underwater training facility, an experienced dive instruc

2、tor lost consciousness during a free dive (with mask and fins). The dive instructor was positioning a weight at the bottom of the pool when he lost consciousness. He was observed by his co-workers and the trainee, who was sent to retrieve him to the surface. Once on the surface, the instructors cond

3、ition was assessed and cardio-pulmonary resuscitation (CPR) was started. CPR was ceased after five or six compressions when the instructors breathing and heartbeat began. The most likely cause of the incident was thought to be shallow water blackout, or more correctly, breath-hold blackout. Although

4、 this is an uncommon event, shallow water blackout potentially can cause serious injury or death in as little as six feet of water. One of the greatest concerns of breath holding during a free dive is unconsciousness during ascent. When the diver descends, the air in his lungs is compressed, raising

5、 the oxygen partial pressure. This partial pressure increase of oxygen (PPO2) satisfies the bodies oxygen demand during descent and while on the bottom. During ascent, the remaining partial pressure of oxygen is reduced rapidly as the hydrostatic pressure on the body lessens. If the partial pressure

6、 of oxygen drops below 11 percent (83.6 mmHg) unconsciousness may result. This danger is increased when hyperventilation has eliminated normal body warning signs of CO2 accumulation.Lesson(s) Learned: Always use the buddy system during free dives at any depth.Recommendation(s): To prevent further mi

7、shaps, many actions can be taken:1. Do not hyperventilate prior to free dive.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2. The buddy system should be used during all water operations.3. A qualified person, whose only task is to watch over all wa

8、ter operations, should be required to provide lifeguard services.4. A briefing on the medical aspects of diving should be held.5. Procedures should be reviewed to determine if they follow accepted diving industry practices for safety, training, SCUBA operations, management and record keeping.6. Pers

9、onnel should be trained in emergency response and life saving skills.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Emergency Preparednessa71 Occupational Healtha71 Safety & Mission AssuranceAdditional Info: Approval Info: a71 Approval Date: 1997-01-08a71 Approval Name: Ronald Montaguea71 Approval Organization: NA3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-