BRITISH MEDICAL JOURNAL LONDON SATURDAY JULY 16 1955 DROWNING BY K. W. DONALD, D.S.C., M.D., D.Sc., F.RC.P. Reader in Medicine, Birmingham University; Physician, Queen Elizabeth Hospital, Birmingham Despite Fhe great interest taken in drowning by various apparent that the blood entering the left side of the lay organizations in this country, there has been a truly heart is greatly diluted and its electrolyte concentration astonishing neglect of this subject by physiologists and proportionately reduced. Haemodilution is inevitably medical men. Another bathing season has begun, and accompanied by haemolysis, and large quantities of the usual crop of drowning accidents may be expected. free haemoglobin appear in the plasma. Since potas- This article reviews the subject of drowning and its sium is released when erythrocytes are lysed there is a treatment, the aims being to stress the principles on considerable gain in plasma potassium from this source, which rational resuscitation must be based and to en- together with a rise due to severe anoxaemia. Thus courage the recording of clinical experience in this field. the plasma potassium concentration is not reduced to In order to understand the problems of treatment of the same degree as that of sodium, with the result that drowned persons it is-necessary to describe the events in the K/Na ratio is greatly increased. This disturbance the body of the victim which may lead to death. The of electrolyte ratios is more dangerous than overall majority of important contributions in recent years have changes in tonicity. The coronary circulation receives been by American workers, particularly H. G. Swann this highly abnormal blood and the myocardium is and his colleagues (1947, 1949, 1951a, 1951b, 1953). Of exposed to serious biochemical insult as well as extreme necessity, most of our information on what happens is anoxia. In a few minutes ventricular fibrillation begins. derived from animal experiments. There is considerable The great overloading of the circulation probably con- variation in the reactions of these animals and still some tributes to this event. It is also possible that there is doubt about certain aspects. These will only be men- extreme pulmonary vasoconstriction when the lungs are tioned when relevant to the problems of therapy. flooded, as occurs in acute and severe anaphylactic shock. After death from drowning the right ventricle Fresh-water Drowning is usually found distended and the left ventricle con- When an animal is totally immersed in fresh water tracted and almost empty. there is an initial period of struggling and apnoea. Ventricular fibrillation usually occurs three to seven From one to two minutes after submersion an involun- minutes after submersion (dogs) and there is an tary inspiration occurs and water is drawn into the immediate and dramatic fall in blood pressure, and the lungs, usually in large quantities. In some cases glottic absence of any effective cardiac output heralds inevit- spasm will prevent the lungs being immediately flooded. able death from absolute cerebral anoxia. The time of- Banting et al. (1938) have shown that local anaesthe- onset of ventricular fibrillation does not appear to be tization of the glottis will prevent such spasm and allow closely related to the degree of haemodilution. Respir- even larger quantities of water to enter the lungs. They atory failure, as judged by cessation of effective respir- also described how many animals swallowed water atory excursions, usually occurs almost simultaneously violently as apnoea became intolerable. This was often with the onset of ventricular fibrillation, but sometimes immediately followed by vomiting and inhalation of it occurs shortly before (10-20 seconds) and sometimes water into the lungs in a series of gasps. In the experi- shortly after (10-20 seconds). ments on dogs of Swann et al. (1947, 1949, 1951b) some It is not so easy to obtain facts concerning the events flooding of the lungs occurred in all animals. in human drowning, but there is no reason to believe When the fresh water enters the lungs there is an they are different. Previous literature would suggest immediate and enormous absorption of this fluid into that a number of human beings are drowned with dry the circulation across the alveolo-capillary membrane. lungs owing to glottic spasm, but little convincing The amount of drowning-fluid absorbed can be esti- evidence has been produced, particularly as it has been mated by the degree of haemodilution or by measuring shown that animals with fatal haemodilution may show the levels of blood concentration of tracer substances almost dry lungs. Lowson (1903), in a remarkable placed in the drowning-fluid before the experiment. It account of his experiences and sensations during near has been shown that an amount of water equivalent to drowning, described how he "breathed in" when 60-150% of the blood volume can enter the circulation apnoea became intolerable and immediately swallowed in a few minutes. The rate of dilution of blood is quite the water in a large gulp. This occurred about ten fantastic. Swann et al. (1951b) cite an experiment in times, and he experienced increasing relief, which he which 72% of the circulating fluid was drowning-fluid later attributed to the sedative effects of mounting three minutes after submersion and probably less than carbon dioxide tensions in the body. He then became two minutes after the inhalation of water. It will be unconscious, but recovered on the surface and after a 493z BTnH 156 DROWNING JuLy 16, 1955 DROWNING MEDICAL JOURNAL number of breaths swam to shore, where he vomited also contain froth, but they are not obstructed by it. When copious quantities of water. He had no signs or symp- the lungs are held up the froth and fluid do not drain out toms of any water in the lungs. It would appear likely of these smaller bronchi. The lung parenchyma contains very varying amounts of fluid, tending to be greater in that if such a victim remained submerged the reflex salt-water drowning for the reasons already mentioned. closure of the glottis would cease and water would be Swann opened the chest of dogs after drowning, cannulated aspirated. the trachea down to the bifurcation, and drained for long Swann et al. (1951b) surmise from data reviewed that periods. In fresh-water drowning, although moderate quan- only one in twenty men drown in fresh water with no tities of water were usually drained off, only a few milli- significant water in the lungs or haemodilution. There is litres of water was obtained in some cases despite great also considerable species variation regarding the onset haemodilution. In salt-water drowning larger quantities of of ventricular fibrillation under these conditions. How- water were obtained. It is unfortunate that figures of immediate drainage of water from the lungs of ever, experiments (Gordon et al., 1954) have shown that intact drowned animals have not been reported. Many patho- occurs one to ventricular fibrillation in three minutes logists consider that it is most unlikely that any important after submersion in fresh water in the larger animals drainage of the lungs or clearing of airways will be obtained (horses, cows, pigs), and it would appear likely that the under such conditions. If this is true then time spent in human is at the same risk. Electrolyte studies of human such manceuvres may only assure the death of the victim victims of drowning in fresh water (Moritz, 1944) owing to the delay of artificial respiration. showed changes capable of precipitating ventricular The stomach may contain very large amounts of the fibrillation in at least half of those studied (Swann et al., drowning-fluid owing to reflex swallowing, and there may 1951b). be evidence of stomach contents in the air-passages. This may be due to the agonal vomiting already described or to Salt-Water Drowning the transfer of stomach contents to the respiratory passages In salt-water drowning the electrolyte concentration of by increased abdominal pressure during artificial respiration. the inhaled fluid is greater than that of blood. Consequently As already mentioned, the right ventricle is usually found there is considerable movement of water from the circu- greatly distended and the left heart contracted. lating blood into the lungs, and in dogs drowning in salt As in other forms of asphyxial death, small local haemor- water there is approximately a 33 % haemoconcentration. rhages may be found in different parts of the body, par- TIhere is, however, no haemolysis or any disturbance of the ticularly in the central nervous system. These haemorrhages K/Na ratio. Ventricular fibrillation does not occur, and are usually far less marked in drowning, and, if they are the heart action fails gradually in five to eight minutes (in conspicuous, asphyxia or violence brfore entry into the dogs) (Swann et al., 1947, 1951b). There is evidence that water must be considered. The most valuable test for the haemoconcentration is not so marked in humans who drowning is the demonstration of difference in electrolyte have drowned in salt water. In acute asphyxial episodes concentration of the blood in the right and left ventricles. where ventricular fibrillation does not occur the systolic This test is now being adopted by all forensic laboratories. blood pressure often remains high for several minutes, The significance of electrolyte changes in the blood after although the diastolic pressure reaches very low levels. long periods of submersion is still in doubt, and studies Swann (1951a) has shown that if the systolic blood pres- continue on this problem. The examination of peripheral sure remains above a certain level (115 mm. Hg approxi- lung and stomach contents for water algae may be extremely mately) then resuscitation by artificial respiration is almrost useful in cases where the cause of death is uncertain.