Anti-shock garments (ASG) may be indicated for obstetric hemorrhage in cases with blood loss above 750mL, pulse greater than 100 beats per minute, and mild hypotension. As a first step in treating shock due to hemorrhage, the ASG can reverse hypovolemic shock and reduce bleeding, buying time for complementary care.
Mechanism of Action
All ASGs compress the lower extremities, reducing the total vascular volume and redirecting blood flow to the vital organs. Pneumatic ASGs accomplish this through the use of inflatable bladders which function like blood pressure cuffs. They are relatively complex compared to non-pneumatic ASGs (NASGs). NASGs apply similar pressure using only tightly fitting neoprene fabric. The ASG is a first resuscitative measure, followed by IV fluids, uterotonics, blood transfusion, and other measures. The device is designed to be worn until the patient’s vital signs have stabilized for 2 hours or more, including blood loss of less than 50mL/hr, pulse below 100bpm, and systolic blood pressure above 100 mmHg. ASGs are not recommended for women with a viable fetus or bleeding above the diaphragm. They are contraindicated for women with mitral stenosis, congestive heart failure, or pulmonary hypertension.
Current Use in High-Resource Settings
ASGs have come in and out of favor in emergency and military medicine. Today they are rarely used in obstetrics, although there are a few documented cases for remote rural populations.
Application in Low-Resource Settings
As of 2010, there were 2000 known cases of obstetric use of NASGs in low-resource settings. These were part of clinical trials in Egypt and Nigeria, designed to determine the safety and efficacy of the Zoex NASG product. Current use has now spread to tertiary care settings where the NASG is first aid, buying time until definitive treatment (in the form of IV fluids, blood, uterotonics, etc.) is available. The device technically also has potential to reduce mortality during transport from one care setting to another; NASGs are used on ambulances in Tamil Nadu, India. Even in tertiary care settings, the device is not always properly cleaned or folded between uses. Widespread adoption remains a challenge due to their relative cost and complexity, but lower-cost devices have been produced with guidance from PATH.