Immersion pulmonary oedema: a cardiological perspective

Abstract

It is postulated that immersion pulmonary oedema (IPE) occurs because of combinations of factors that each increase the hydrostatic pressure gradient between the pulmonary capillaries and the alveoli. The factors, by definition, include the effects of immersion, particularly raised central blood volume and hence cardiac filling pressures. Breathing against a negative pressure is important but the magnitude of the effect depends on the relation of the diver's lung centroid to the source of the breathing gas and the breathing characteristics of diving equipment. Other factors are cold-induced vasoconstriction, exertion and emotional stress, but variations of the responses of individuals to these stimuli are important. Hypertension is the most frequent cardiovascular disease predisposing to IPE but other medical conditions are implicated in some patients.

Keywords: Case reports; Cold; Exercise; Hypertension; Rebreathers; Renal artery stenosis; Takotsubu cardiomyopathy; Transpulmonary pressure.

Figure 1

The left chest X-ray is of the first diver recognised as having pulmonary oedema triggered by diving; the right chest X-ray is of the same diver four weeks later

Figure 2

Left ventriculogram of Case 7 who had Takotsubo cardiomyopathy associated with immersion pulmonary oedema, showing the end diastolic frame (left panel) and end systolic frame