Docstoc

Near drowning

Document Sample
Near drowning Powered By Docstoc
					           Near drowning
          JEROME H. MODELL, M.D.

           ABSTRACT Several conditions that contribute to drowning and near drowning must be considered in
           the treatment of near-drowned victims. Regardless of the cause, mechanical ventilation should begin as
           soon as possible and closed-chest cardiac massage should be administered when there is any question
           about the adequacy of cardiac output. After aspiration of either fresh or seawater, a large intrapulmo-
           nary physiologic shunt can occur, which requires aggressive mechanical ventilatory support to ensure
           adequate oxygenation and to return pulmonary function to normal. Near drowning is a multisystem
           disease and, while abnormalities of the lung and brain have been emphasized, definitive therapy must
           be tailored to each patient and must address all of the patient's needs.
           Circulation 74(suppl IV), IV-27, 1986.

SEVERAL CONDITIONS that contribute to drowning                            Some have advocated that a subdiaphragmatic ab-
and near drowning must be considered in the treatment                     dominal thrust (Heimlich maneuver) be used routinely
of near-drowned victims. The nonswimmer in deep                           before initiating CPR.2 Because near-drowning vic-
water usually will struggle for survival, whereas a                       tims frequently swallow large amounts of water, there
swimmer suffering from physical exhaustion will not.                      is a risk that water will be expelled from the stomach
Persons who hyperventilate before swimming under-                         with subsequent aspiration into the lungs. Further-
water may lose consciousness secondary to cerebral                        more, many near-drowning victims aspirate relatively
hypoxia and, as a result, begin breathing underwater.                     small amounts of water; also, freshwater is rapidly
Alcohol can interfere with judgment and, in excess,                       absorbed from the lungs into the circulation. Thus, this
can act as an anesthetic. The person who dives into                       maneuver is not recommended unless a clear airway
shallow water must be suspected of having a head or a                     cannot be obtained by other means or there is no re-
neck injury. Persons who swim or plunge into cold                         sponse to basic CPR, in which case a subdiaphrag-
water will be hypothermic, which, in turn, can cause                      matic abdominal thrust is indicated.3
ventricular fibrillation or near drowning, with or with-                     Because aspirated freshwater is absorbed rapidly
out aspiration of water. Hypothermia decreases meta-                      into the circulation and then redistributed, even when
bolic rate and, thus, such victims may withstand respi-                   the quantity of water is large, an increase in blood
ratory and circulatory arrest for a longer period than a                  volume is no longer present 60 min after aspiration in
victim who is normothermic. In any of these cases,                        experimental animals.4 Seawater is hypertonic, and
immediate therapy at the scene should concentrate on                      thus draws fluid from the circulation into the lungs.
ventilation, oxygenation, and circulatory support. '                      There is good evidence that most near-drowned hu-
   Mechanical ventilation should start as soon as possi-                  mans do not aspirate large quantities of water. ' This is
ble, preferably in the water, provided, of course, that                   substantiated by the fact that abnormal serum electro-
the rescuer can perform mouth-to-mouth or mouth-to-                       lyte concentrations that require specific treatment are
nose ventilation in the water without also near drown-                    rarely seen, except when an extremely concentrated
ing. Because apnea usually precedes cardiac standstill                    salt solution, such as water from the Dead Sea, is
after water has been aspirated experimentally, if me-                     aspirated.5
chanical ventilation is provided, circulatory support                        The primary immediate problem is that significant
may not be needed. Since the near-drowned victim                          intrapulmonary shunting occurs and persists even after
may be suffering from severe vasoconstriction, deter-                     ventilation and circulation have been restored. After
mination of whether there is mechanical cardiac action                    aspiration of seawater, this shunt is likely due to fluid-
may be difficult. Unless a carotid, femoral, or radial                    filled but perfused alveoli and, after aspiration of
pulse is definitely palpable, closed-chest cardiac mas-                   freshwater, to unstable alveoli due to an alteration in
sage should be started immediately. Supplemental                          the surface tension properties of pulmonary surfac-
oxygen should be provided as soon as it is available.                     tant.' In either case, the intrapulmonary shunt de-
   From the Department of Anesthesiology, University of Florida Col-      creases rapidly with the application of continuous posi-
lege of Medicine, J. Hillis Miller Health Center, Gainesville.            tive airway pressure (CPAP). After aspiration of
   Address for correspondence: Dr. Jerome H. Modell, University of         seawater, both CPAP with spontaneous ventilation and
Florida College of Medicine, Box J-254, J. Hillis Miller Health Center,
Gainesville, FL 32610-0254.                                                controlled mechanical ventilation (CMV) with positive
Vol. 74(suppl IV), December 1986                                                                                              IV-27
MODELL

end-expiratory pressure (PEEP) have been demonstrat-        elevated, then it should be monitored and hyperventi-
ed to dramatically decrease intrapulmonary shunting         lation, fluid restriction, and barbiturate coma may well
and increase arterial oxygen tension. After aspiration      be beneficial. The pros and cons on this subject are
of freshwater, results are similar with CMV and PEEP;       beyond the scope of this report.
however, the response to CPAP with spontaneous ven-            In conclusion, the hallmark of therapy for near
tilation varies. In some victims, a favorable response      drowning remains prompt, effective CPR. All near-
is very rapid; in others, the response is not optimal       drowned victims should be transported from the scene
until mechanical ventilation is applied with CPAP.          to a hospital for further evaluation and therapy as nec-
   The application of CPAP with or without mechan-          essary. Usually, the most crucial part of therapy is the
ical ventilation may lead to hypotension. This is           early, aggressive treatment of the pulmonary lesion,
caused by a decrease in cardiac output secondary to the     whether freshwater or seawater has been aspirated.
increase in intrapleural pressure with concomitant rela-    Definitive therapy needs to be tailored to the individual
tive hypovolemia after aspiration of either seawater or     patient.
freshwater. Thus, even though the intrapulmonary
shunt may decrease and arterial oxygen tension may          References
                                                             1. Modell JH: Drowning. In Staub NC, Taylor AE. editors: Edema.
increase, oxygen delivery is not improved. Experi-              New York, 1984, Raven Press, p 679
mentally, cardiac output can best be supported by the        2. Heimlich HJ: The Heimlich maneuver: first treatment for drowning
administration of intravenous fluid, which increases            victims. Emerg Med Serv 10: 58, 1981
                                                             3. Modell JH: Is the Heimlich maneuver appropriate as first treatment
oxygen delivery.4 Intensive pulmonary support should            for drowning? Emerg Med Serv 10: 63, 1981
be instituted early and continued in an intensive care       4. Tabeling BB, Modell JH: Fluid administration increases oxygen
                                                                delivery during continuous positive pressure ventilation after fresh-
environment with appropriate invasive monitoring as             water near drowning. Crit Care Med 11: 693, 1983
indicated by the severity of the insult or other system      5. Modell JH: Serum electrolyte changes in near-drowning victims.
                                                                JAMA 253: 557, 1985
failure.                                                     6. Bergquist RE, Vogelhut MM, Modell JH, Sloan SJ, Ruiz BC:
   During the past 5 years, there has been considerable         Comparison of ventilatory patterns in the treatment of freshwater
                                                                near drowning in dogs. Anesthesiology 52: 142, 1980
attention given to cerebral salvage after near drowning      7. Conn AW, Montes AG, Barker GA, Edmonds JF: Cerebral salvage
and many have advocated the routine use of dehydra-             in near drowning following neurological classification by triage.
tion, hyperventilation, hyperoxia, hypothermia, mus-            Can Anaesthesiol Soc J 27: 201, 1980
                                                             8. Modell JH, Conn AW: Current neurological considerations in near
cle paralysis, barbiturate coma, and corticosteroids.7          drowning. Can Anaesthesiol Soc J 27: 197, 1980 (editorial)
The literature in this regard is quite confusing because,    9. Modell JH, Graves SA, Kuck EJ: Near drowning: correlation of
                                                                level of consciousness and survival. Can Anaesthesiol Soc J 27:
while some recommend such techniques, others point              211, 1980
to their complications and condemn them. To date, no        10. Rogers MC: Near drowning: cold water on a hot topic? J Pediatr
                                                                106: 603, 1985
well-controlled study has been performed to support         11. Conn AW, Barker GA: Fresh water drowning and near drowning
such therapy as routine.8'-" If intracranial pressure is            an update. Can Anaesthesiol Soc J 31: S38, 1984




iv-28                                                                                                            CIRCULATION

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:24
posted:12/15/2011
language:English
pages:2