Venous Pooling in Suspension Syndrome Assessed with Ultrasound

Abstract

IntroductiondSuspension syndrome describes a potentially life-threatening event during passive suspension on a rope. The pathophysiological mechanism is not fully understood; however, the most widespread hypothesis assumes blood pools in the lower extremities, prompting a reduction in cardiac preload and cardiac output and leading to tissue hypoperfusion, loss of consciousness, and death. The aim of this study was to assess venous pooling by ultrasound in simulated suspension syndrome using human subjects.MethodsdIn this trial, 20 healthy volunteers were suspended in a sit harness for a maximum of 60 min with and without preceding exercise. Venous pooling was assessed by measuring the diameter of the superficial femoral vein (SFV) with ultrasound at baseline in supine and standing positions as well as during and after suspension.ResultsdSFV diameter increased and blood flow became progressively sluggish. In 30% of the tests, near syncope occurred. However, SFV diameter did not differ between subjects with and without near syncope.ConclusionsdFree hanging in a harness leads to rapid venous pooling in the lower limbs. The most important measure to prevent suspension syndrome might be constant movement of the legs.

Delaying Suspension Syndrome Onset in Aerially Suspended Victims Through Leg Raising

“…6 Although we did not measure venous return, participants unexpectedly displayed venous pooling in the lower extremities in a mottling pattern consistent with livedo reticularis, a process in which blood flow to the superficial, cutaneous arteries is obstructed. 11,15,16 Progression of symptoms appeared to follow a sequential pattern: Participants developed paresthesia in the lower extremities, followed by pallor, mottling consistent with livedo reticularis, and presyncopal symptom onset. 15 We documented the presence of livedo reticularis spontaneously with written notes and photographs, as it was an unexpected finding.…”

Hemodynamic changes in prone position - a non‑invasive physiological study

“…Hodnocení venózního poolingu a posouzení změn srdečního preloadu je možné nepřímo použitím ultrazvukových metod [13].…”

Evidence-Based Versus Myth-Based Treatment of Suspension Syndrome

“…Passive suspension is the problem, rather than compression of vessels by the harness. 12 Harness management should not delay rescue or first aid.…”

“…Ultrasound showed stasis of blood in the vein while participants were passively suspended, followed by rapid resumption of venous flow with movement. 12,13 Although the true incidence of suspension syndrome is not known, it is rare. These studies, consistent with other studies, suggest that 30% of climbers and others suspended on rope are at risk.…”

“…A study published in this issue of Wilderness & Environmental Medicine and a related study by the same group have brought more clarity to suspension syndrome. 12,13 The authors examined the widespread belief that blood pools in the legs when an individual is passively suspended. These studies confirmed this hypothesis by using ultrasound to visualize the superficial femoral vein, which, despite its name, is a deep vein.…”