Effects of different peep levels on mesenteric leukocyte-endothelial interactions in rats during mechanical ventilation

Authors

  • Priscila Aikawa Universidade de São Paulo; Faculdade de Medicina; Department of Cardiopneumology; LIM-11 and LIM-61
  • Sandra Helena Poliselli Farsky University of São Paulo; School of Pharmacy; Department of Clinical and Toxicological Analyses
  • Maria Aparecida de Oliveira University of São Paulo; Institute of Biomedical Sciences; Department of Pharmacology
  • Rogério Pazetti Universidade de São Paulo; Faculdade de Medicina; Department of Cardiopneumology; LIM-11 and LIM-61
  • Thaís Mauad Universidade de São Paulo; Faculdade de Medicina; Department of Pathology; LIM-05
  • Paulina Sannomiya Universidade de São Paulo; Faculdade de Medicina; Department of Cardiopneumology; LIM-11 and LIM-61
  • Naomi Kondo Nakagawa Universidade de São Paulo; Faculdade de Medicina; Department of Cardiopneumology; LIM-11 and LIM-61

DOI:

https://doi.org/10.1590/S1807-59322009000500012

Keywords:

Mechanical ventilation, Leukocyte-endothelial interactions, Microcirculation, Mesentery

Abstract

INTRODUCTION: Mechanical ventilation with positive end expiratory pressure (PEEP) improves oxygenation and treats acute pulmonary failure. However, increased intrathoracic pressure may cause regional blood flow alterations that may contribute to mesenteric ischemia and gastrointestinal failure. We investigated the effects of different PEEP levels on mesenteric leukocyte-endothelial interactions. METHODS: Forty-four male Wistar rats were initially anesthetized (Pentobarbital I.P. 50mg/kg) and randomly assigned to one of the following groups: 1) NAIVE (only anesthesia; n=9), 2) PEEP 0 (PEEP of 0 cmH2O, n=13), 3) PEEP 5 (PEEP of 5 cmH2O, n=12), and 4) PEEP 10 (PEEP of 10 cmH2O, n=13). Positive end expiratory pressure groups were tracheostomized and mechanically ventilated with a tidal volume of 10 mL/kg, respiratory rate of 70 rpm, and inspired oxygen fraction of 1. Animals were maintained under isoflurane anesthesia. After two hours, laparotomy was performed, and leukocyte-endothelial interactions were evaluated by intravital microscopy. RESULTS: No significant changes were observed in mean arterial blood pressure among groups during the study. Tracheal peak pressure was smaller in PEEP 5 compared with PEEP 0 and PEEP 10 groups (11, 15, and 16 cmH2O, respectively; p<0.05). After two hours of MV, there were no differences among NAIVE, PEEP 0 and PEEP 5 groups in the number of rollers (118±9,127±14 and 147±26 cells/10minutes, respectively), adherent leukocytes (3±1,3±1 and 4±2 cells/100µm venule length, respectively), and migrated leukocytes (2±1,2±1 and 2±1 cells/5,000µm², respectively) at the mesentery. However, the PEEP 10 group exhibited an increase in the number of rolling, adherent and migrated leukocytes (188±15 cells / 10 min, 8±1 cells / 100 µm and 12±1 cells / 5,000 µm², respectively; p<0.05). CONCLUSIONS: High intrathoracic pressure was harmful to mesenteric microcirculation in the experimental model of rats with normal lungs and stable systemic blood pressure, a finding that may have relevance for complications related to mechanical ventilation.

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Published

2009-05-01

Issue

Section

Clinical Sciences

How to Cite

Aikawa, P., Farsky, S. H. P., Oliveira, M. A. de, Pazetti, R., Mauad, T., Sannomiya, P., & Nakagawa, N. K. (2009). Effects of different peep levels on mesenteric leukocyte-endothelial interactions in rats during mechanical ventilation . Clinics, 64(5), 443-450. https://doi.org/10.1590/S1807-59322009000500012