The Effect of 7.5% Hypertonic Saline Resuscitation and Normal Saline Resuscitation on Acute Lung Injury after Hemorrhagic Shock

ABSTRACT

PURPOSE: To investigate the hypothesis that resuscitation with hypertonic saline (HTS) in hemorrhagic shock (HS) will improve the pulmonary function and inflammatory changes in post-hemorrhage induced acute lung injury. METHODS: HS was induced in anesthetized Swiss-Webster mice by removing 0.025cc blood/g. body weight via the carotid artery while under blood pressure monitoring. Mice were divided into 5 groups Group I (n=12) were cannulated but not bled (sham); Group II (n=12) were bled and received 4mL/kg 7.5% HTS; Group III (n=10) were bled and received 3 times their shed blood (SB) volume of normal saline (NS); Group IV (n=11) were bled and received SB and 4mL/kg 7.5% HTS; Group V (n=9) were bled and received SB and two times their SB volume of NS after 30 minutes shock. Serum lactates (LA) were evaluated at the end of the shock period and after resuscitation. Pulmonary function was measured by whole-body plethysmography prior to any instrumentation and again 24hr, 48hr and 72hr after resuscitation. Pulmonary inflammation was assessed by quantifying bronchoalveolar lavage neutrophil infiltration (BALN) and myeloperoxidase (MPO) activity after 72hr of observation. RESULTS: There were no differences in baseline BP, shock BP, shock LA and LA after resuscitation in each shock group. The survival rates were as follows Group I, 75.0%; Group II, 33.3%; Group III, 60%; Group IV, 81.8%; and Group V, 88.8% (p=0.046). There were no significant differences in the changes of airway resistance after resuscitation in each group. BALN and MPO activity in Group III were increased. CONCILUSION HTS resuscitation alone was associated with higher mortality. HTS was decreased pulmonary inflammation but it did not alter respiratory function.