Is Hypertonic Saline Resuscitation Safe in ‘Uncontrolled’ Hemorrhagic Shock?

Abstract

Hypertonic saline treatment of hemorrhagic shock (HS) results in increased systemic blood pressure, cardiac output, and splanchnic blood flow. To determine whether this elevation in blood pressure and flow would augment blood loss from injured intra-abdominal vessels and thus enhance mortality rate, “controlled” HS was induced by bleeding of 20 ml/kg from an arterial cannula that was immediately occluded after hemorrhage, and “uncontrolled” HS was induced by incision of three major radicals of the ileocolic artery leading to continuous intra-abdominal blood loss. Seventy rats were divided into eight groups: Group I (n = 5) underwent carotid artery and jugular vein cannulation and was observed for 3 hr; in Group II (n = 10) “controlled” HS was induced by arterial hemorrhage of 20 ml/kg; in Group III (n = 7) “controlled” HS was treated by 5 ml/kg NaCl 0.9%; in Group IV (n = 8) “controlled” HS was treated by 5 ml/kg NaCl 7.5%; in Group V (n = 4) midline laparotomy and identification of the ileocolic artery was performed; in Group VI (n = 9) “uncontrolled” HS was induced by incision of three major branches of the ileocolic artery; in Group VII (n = 9) “uncontrolled” HS was treated by 5 ml/kg NaCl 0.9%, and in Group VIII (n = 18) “uncontrolled” HS was treated by 5 ml/kg NaCl 7.5%. In untreated “controlled” HS (Group II), mean arterial pressure (MAP) fell to 35 torr followed by a spontaneous rise to 62 torr (p < 0.001) after 3 hr with a survival of 80% of the animals. Treatment of “controlled” HS with 5 ml/kg NaCl 7.5% increased MAP from 35 to 80 torr (p < 0.005), with 100% survival. “Uncontrolled” hemorrhage (Group VI) resulted in an immediate fall in MAP to 39.3 torr followed by a spontaneous rise to 66.8 torr (p < 0.005) after 2 hr and then a gradual fall to 44.2 torr (p < 0.01) after 3 hr. Infusion of hypertonic saline in “uncontrolled” HS (Group VIII) increased intra-abdominal blood loss with a steep fall in MAP and death of 66% of the rats within 1 hr and of 94% after 2 hr. The mean survival time of this group was 47.9 min compared to 168 min (p < 0.01) in untreated animals (Group VI). It is concluded that hypertonic saline treatment of “uncontrolled” hemorrhagic shock increases blood loss, leading to a fall in arterial blood pressure and early mortality. This risk should be considered in treatment of hemorrhagic shock following abdominal trauma.