Basic life support in a diving bell and deck decompression chamber.
Basic life support (BLS) in a diving bell (DB) or deck decompression chamber (DDC) is difficult due to the confined space and limited equipment. Retrieval of the unconscious diver into the DB requires the use of a pulley system. Once inside the bell, space limitations dictate that any resuscitative efforts are attempted with the victim (diver) either suspended in the upright position by the pulley system or lying against the DB's curved side in a semi-supine position. BLS at best achieves a carotid artery systolic blood pressure of 40 mmHg or 30% of cardiac output in the supine position and, therefore, would be ineffective for a diver suspended on a pulley due to inadequate cerebral perfusion. Compression-only cardiopulmonary resuscitation (CPR) may be the only option with the victim lying against the bell's side due to an inability to perform rescue breathing. However, compression ventilation CPR is possible in a DDC provided space limitations do not deny the rescuers access to the patient. The use of an automatic external defibrillator in a hyperbaric chamber has not been studied and therefore cannot be recommended in a DB or DDC. The laryngeal mask airway has been recommended by the Diving Medical Advisory Committee, but an accompanying study suggests that a new device, the i-gel™ without an inflatable cuff, may be a more suitable airway option for the future.
A specialist in the Hyperbaric Medicine Unit, Department of Anaesthesia and Intensive Care, Royal Adelaide Hospital, Adelaide, South Australia 5001, Australia, Phone: +61-(0)8-8222-5116, Fax: +61-(0)8-8232-4207, E-mail: cacott@optusnet.com.au.
Christopher John
CJ
Acott