Effects of continuous negative extra-abdominal pressure on cardiorespiratory function during abdominal hypertension: An experimental study

Franco Valenza, Manuela Irace, Massimiliano Guglielmi, Stefano Gatti, Nicola Bottino, Cecilia Tedesco, Micol Maffioletti, Patrizia Maccagni, Tommaso Fossali, Gabriele Aletti, Luciano Gattinoni

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Abstract

Objective: To investigate whether negative extra-abdominal pressure (NEXAP) improves respiratory function and induces a blood shift from the intrathoracic compartment and to assess whether these effects are influenced by abdominal pressure. Design and setting: Prospective, randomized, controlled trial in the animal laboratory of a university hospital. Subjects: Eight sedated and paralyzed pigs (19.6±3.4 kg). Interventions: Application of NEXAP (-20 cmH2O). Measurements and results: Airway, esophageal, gastric and central venous pressures were recorded simultaneously. Intrathoracic blood volume was assessed by PiCCO. The effects of NEXAP were assessed with and without abdominal hypertension by intraperitoneal insufflation of helium. NEXAP caused a lasting drop of gastric (1.97±2.26 mmHg) and esophageal (1.21±0.67 mmHg) pressures, while end-expiratory airway pressure was similar, hence transpulmonary pressure increased. Intrathoracic blood volume dropped from 358±47 to 314±47 ml. The fall was associated with a decrease in central venous pressure (R2=0.820). When peritoneal pressure was raised (24.7±5.5 mmHg), the effects were less marked. However, the difference between negative pressure around the abdomen and the pressure inside the abdomen (effective NEXAP) was correlated with the proportional changes in intrathoracic blood volume (R2=0.648), being greater with more negative effective NEXAP. NEXAP improved chest wall elastance during abdominal hypertension (from 0.067±0.023 to 0.056± 0.021 cm H2O/ml). Conclusions: NEXAP increases lung volume and causes a shift of blood from the intrathoracic compartment. It needs to be tailored against abdominal pressure to be effective.

Original languageEnglish
Pages (from-to)105-111
Number of pages7
JournalIntensive Care Medicine
Volume31
Issue number1
DOIs
Publication statusPublished - Jan 2005

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Keywords

  • Abdominal
  • Animal experimentation
  • Decompression
  • Fluid shifts
  • Respiratory mechanics

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine

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