Lack of a tachycardic response to hypotension with ruptured ectopic pregnancy.

The concept that tachycardia is a reliable indicator of shock has recently been challenged in patients with hemoperitoneum. The purpose of this study was to document whether patients with ruptured ectopic pregnancy manifest a tachycardic response to hypotension and to define the relationship between hemodynamic response and blood loss resulting from hemoperitoneum. A retrospective chart review of 154 patients with documented ectopic pregnancy identified 20 (13.0%) hypotensive patients (systolic blood pressure less than or equal to 90 mm Hg). Eleven (55%) patients were not tachycardic (pulse rate less than 100 beats/min) and nine (45%) patients were tachycardic. The quantity of hemoperitoneum varied widely in each group and did not correlate with the hemodynamic response. These results support the proposed theory that hemoperitoneum may trigger a parasympathetic reflex, resulting in a pulse rate inappropriate for the degree of hypotension. A vasovagal reflex may play a role in those patients without significant hemoperitoneum. The diagnosis of hypovolemic shock must be considered when hypotension is present without tachycardia.