Victims of submersion incidents suffer global hypoxaemia and if arrested, global ischaemia. Associated injuries are aspiration pneumonitis and hypothermia. Aspiration of water and gastric contents is common (see Chapter 22.2). In addition, hypothermia (see Chapter 22.4) may be present, but unless the victim was subject to severe environmental hypothermia such as being submersed in ice-cold water (<5°C) or has profound afterdrop after removal from water, this reflects lack of perfusion and is a bad prognostic sign. Hypothermia should be treated but temperature not permitted to rise above 35°C if cardiac arrest has occurred (see Chapter 2.3).
The outcome is often determined by the extent of neurological injury. Bad prognostic indicators are prolonged duration of submersion, lack of bystander CPR, prolonged prehospital resuscitation, pulseless arrhythmia on arrival at hospital, fixed dilated pupils, severe acidosis and apnoea. Nonetheless, vigorous resuscitation should be instituted on arrival in hospital of the pulseless victim, if not already commenced by ambulance personnel, in order to clarify the clinical details whilst continuing resuscitation.
Intubation and mechanical ventilation with 100% oxygen should be instituted immediately. Regurgitation of stomach contents should be anticipated and a rapid sequence intubation technique with cricoid pressure should be used. Sedative drugs with cardiovascular depressive actions should not be used, or in minimally required doses only. The lung compliance is likely to be poor and it may be necessary to insert a larger-than-usual uncuffed or a cuffed endotracheal tube (preferred) to prevent a leak around the tube, to obtain adequate lung inflation in the setting of acute respiratory distress syndrome (ARDS) in order to achieve oxygenation. After restoration of cardiac rhythm myocardial contractility should be measured with echocardiography and optimised with inotropic agents.
During resuscitation, the goal is to provide maximum opportunity for cerebral recovery and this is achieved by restoring cerebral perfusion with well oxygenated blood and the avoidance of factors that decrease cerebral perfusion pressure. It is thus vital to restore cardiac output and blood pressure, to oxygenate blood and to avoid factors that would increase intracranial pressure, such as venous obstruction. Hypocapnia, hypercapnia, hypoglycaemia and hyperglycaemia should be avoided and convulsions treated.
Any pulseless arrhythmia may be encountered and should be managed along standard lines.
There are no important clinical differences between fresh and salt-water immersion. Altered levels of serum electrolytes, especially sodium and potassium, may be detected, but are uncommon and in any case do not influence acute resuscitation.
