Influence of asymptomatic pneumonia on the response to hemorrhage and resuscitation in swine

Abstract

INTRODUCTION:Investigation of resuscitation fluids in our swine hemorrhage model revealed moderate to severe chronic pneumonia in five swine at necropsy. Our veterinary staff suggested that we perform a retrospective analysis of prospectively collected data from these animals. We compared the data to that of ten healthy swine to determine the physiologic consequences of the added stress on our hemorrhage/resuscitation model.METHODS:Anesthetized, immature female swine (40 ± 5 kg) were instrumented for determining arterial and venous pressures, cardiac output and urine production. A controlled hemorrhage of 20 ml/kg over 4 min 40 sec was followed at 30 min by a second hemorrhage of 8 ml/kg and resuscitation with 1.5 ml/kg/min of LR solutions to achieve and maintain systolic blood pressure at 80 ± 5 mmHg for 3.5 hrs. Chemistries and arterial and venous blood gasses were determined from periodic blood samples along with hemodynamic variables.RESULTS:There were significant decreases in survival, urine output, cardiac output and oxygen delivery at 60 min and O2 consumption at 120 min in the pneumonia group compared to the non‐pneumonia group. There were no differences in other metabolic or hemodynamic data between the groups.CONCLUSION:Although pneumonia had little influence on pulmonary gas exchange, it influenced cardiac output, urine output and survival compared to healthy swine, suggesting a decrease in the physiologic reserve. These data may be relevant to patients with subclinical infection who are stressed by hemorrhage and may explain in part why some similarly injured patients require more resuscitation efforts than others.

Swine hemorrhagic shock model and pathophysiological changes in a desert dry-heat environment

“…Accordingly, to PLOS ONE simulate physiological responses to hemorrhagic shock in humans, we performed splenectomy in the NTHS and DTHS groups. The spleen was immediately weighed, and the piglet was infused with warm lactated Ringer's solution (Minsheng Pharma, Hangzhou, China) at three times the volume of the resected spleen to replace the blood volume contained in the removed spleen [18,19]. A complete splenectomy and 1/4 resection of the left liver were performed to simulate liver trauma and complete hemostasis.…”

Molecular mechanisms of trauma-induced acute kidney injury: Inflammatory and metabolic insights from animal models

“…Although the majority of studies in animal models of HS have focused on the effects of various fluid resuscitation formulations on hemodynamics and survival [131], a few have included renal function. In a study of asymptomatic pneumonia after HS, pigs resuscitated with LR had significantly lower urine output compared to healthy A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 26 pigs, suggesting some degree of renal failure [132]. In addition, the effect of hemorrhage and hypertonic fluid resuscitation in dehydrated animals was postulated to compromise renal function.…”

Original research articles on the cardiopulmonary system recently appeared in Brazilian clinical and surgical journals

“…Hypovolemia. Experiments on hypovolemic hypotension and shock contributed five entries [209][210][211][212][213] . In a porcine model of severe hemorrhagic hypotension, hyperkalemia accompanies hemorrhagic shock and correlates with mortality 209 .…”

“…A novel fluid resuscitation strategy is described which modulates pulmonary transcription factor activation in a murine model of hemorrhagic shock; HSPTX exerts its anti-inflammatory effects by interfering with nuclear factor kappa B/cAMP response element-binding protein (NF-κB-CREB) competition for the coactivator CREB-binding protein (CBP) in lung tissue, thus affecting pro-inflammatory mediator production; it may therefore have therapeutic potential in the attenuation of ischemia-reperfusion injury observed after severe hemorrhagic shock 212 . Severe chronic asymptomatic pneumonia in swine has been found to affect the response to hemorrhage and resuscitation; it had little influence on pulmonary gas exchange, but influenced cardiac output, urine output and survival compared to healthy swine, suggesting a decrease in the physiologic reserve 213 .…”