Am. J. Respir. Crit. Care Med., Vol 151, No. 3, Mar 1995, 719-723.
Effect of synchronized, systolic, lower body, positive pressure on hemodynamics in human septic shock. A pilot study
JP Gunter, BP deBoisblanc, BS Rust, WD Johnson and WR Summer
Department of Medicine, Louisiana State University Medial School, New Orleans.
The pathophysiologic disturbance observed in volume-resuscitated patients
with septic shock is primarily that of hyperdynamic circulation with a
markedly reduced systemic vascular resistance. We hypothesized that
external, mechanically applied, phasic lower body positive pressure could
increase systemic vascular resistance and, thus, blood pressure in patients
with refractory septic shock. A total of nine studies were performed on
seven patients with septic shock refractory to volume resuscitation and
vasopressors. All pre-existing therapies were continued unaltered during
the study period. Phasic lower body positive pressure was produced by rapid
synchronized inflation of pneumatic fabric cuffs fitted around each lower
extremity. The cuffs were inflated for 200 ms to a pressure of 150 mm Hg,
and the timing of inflation was adjusted to coincide with the peak systolic
arterial pressure. Hemodynamic measurements were obtained at baseline and
after 15 min of phasic lower body positive pressure. This off-on cycle was
repeated twice for each study. Phasic lower body positive pressure
increased mean arterial pressure by 12% and cardiac index by 14% (p = 0.01)
over baseline (p < or = 0.001). Heart rate, central venous pressure,
pulmonary capillary wedge pressure, arterial pH, arterial pO2, and mixed
venous pO2 were unchanged. Synchronized external systolic compression of
the lower extremities increased mean arterial pressure and cardiac output
in seven patients with refractory septic shock. This hemodynamic
improvement was independent of changes in calculated systemic vascular
resistance.
