Hemoptysis and Breath-Holding Diving

Military Medicine, Jul 2006 by Kalemoglu, Murat, Keskin, Ozcan

Discussion

During diving, immersion causes central blood pooling, thus increasing cardiac preload.2 Exercise causes an increase in cardiac output. Cold exposure increases both preload and afterload by vasoconstriction.12,13 Slade et al.14 report on eight divers using a self-contained underwater breathing apparatus (scuba) who developed acute pulmonary edema, which occurred in cold water. A combination of these mechanisms, as occurs during diving, along with an increase in intrathoracic blood volume could be responsible for an excessive increase in pulmonary capillary pressure. As a result, increased capillary pressure can disrupt the blood-gas barrier and causes alveolar edema or hemorrhage.

Boussuges et al.15 published a report of three cases of nonfatal hemoptysis in breath-hold divers. They speculated that factors such as immersion, exercise, and exposure to cold, and an increase in ambient pressure could account for the hemoptysis. In that study, all of the divers had ingested acetylsalicylic acid a few hours before diving. These authors reported that acetylsalicylic acid usage might have aggravated the bleeding through its anti-platelet effect, but it is known that this drug does not cause spontaneous bleeding from intact vessels.

Most of the factors that can cause hemoptysis were not obvious in our patient, who experienced hemoptysis when he dove to a shallower depth than his limit. He had no known pulmonary or cardiac diseases, and he was not receiving any medications, including acetylsalicylic acid. He dove in Mediterranean waters during the spring, when the water temperature is not very low. He was not overhydrated and had no water aspiration. However, all of the divers performing in these military exercises did the same maneuver: voluntary diaphragmatic contraction at the depth. Breathhold divers to increase the breath-hold time use this maneuver. Diaphragmatic contractions cause markedly negative intrapleural pressure generated by a forceful inspiratory effort against an obstructed extrathoracic airway.16 Markedly negative intrapulmonary pressure increases venous return, pulmonary blood volume, and pulmonary capillary hydrostatic pressure while lowering the perivascular interstitial hydrostatic pressure.10,11,16

However, this maneuver has only been cited previously in three other cases. We contribute another case to the literature without confounding circumstances and propose a physiologic mechanism.16

References

1. Anthonisen NR,: Physiology of diving: respiration. In: The Physician's Guide to Diving Medicine, pp 71-85. Edited by Shilling CW, Carlston CB, Mathias RA. New York, Plenum Press, 1984.

2. Hong Suk-Ki: Breath-hold diving, In: Hove and Davis' Diving Medicine, pp 65-74. Edited by Bove AA . Philadelphia W.B. Saunders Co., 1997.

3. West JB, Mathieu-Costello O: Structure, strength and failure of the pulmonary blood-gas barrier. In: European Respiratory Monograph: Respiratory Mechanics, pp 171-202. Edited by Miltc-Emili J. Sheffield, U.K., ERS Journals Ltd., 1999.