Читать книгу Emergency Medical Services - Группа авторов - Страница 181

Blood pressure is dependent on the maintenance of cardiac output. Any condition that inhibits venous return can be anticipated to decrease cardiac output and induce shock. A number of clinical conditions exist in which venous return to the thorax and heart are reduced. These conditions include tension pneumothorax, cardiac tamponade, and massive pulmonary embolism.

Obstructive causes of shock are often difficult to diagnose and treat. Clinical signs of decreased venous return include neck vein distension and cyanosis, often in the setting of shock. Identifying these signs requires the clinician to complete an efficient, organized assessment. Shock in the setting of neck vein distention and cyanosis should lead the EMS clinician to suspect an obstructive condition as the cause.

If possible, the obstruction should be resolved, such as by decompression of a tension pneumothorax. However, when the primary problem cannot be treated successfully in the field (e.g., massive pulmonary embolus or cardiac tamponade), intravenous fluids may be helpful in increasing preload and temporizing the condition.