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(plus or minus)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(plus or minus)2.26 mmHg) and esophageal (1.21(plus or minus)0.67 mmHg) pressures, while end-expiratory airway pressure was similar, hence transpulmonary pressure increased. Intrathoracic blood volume dropped from 358(plus or minus)47 to 314(plus or minus)47 ml. The fall was associated with a decrease in central venous pressure (R2=0.820). When peritoneal pressure was raised (24.7(plus or minus)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(plus or minus)0.023 to 0.056(plus or minus) 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. (copyright) Springer-Verlag 2004.
|Titolo:||Effects of continuous negative extra-abdominal pressure on cardiorespiratory function during abdominal hypertension : An experimental study|
|Parole Chiave:||abdominal pressure; airway pressure; animal experiment; article; blood volume; central venous pressure; continuous negative extraabdominal pressure; controlled study; decompression; elasticity; esophagus pressure; hypertension; nonhuman; paralysis; peritoneum; respiratory function; sedation; stomach pressure; thorax pressure; thorax wall; university hospital|
|Settore Scientifico Disciplinare:||Settore MED/41 - Anestesiologia|
|Data di pubblicazione:||gen-2005|
|Digital Object Identifier (DOI):||10.1007/s00134-004-2483-2|
|Appare nelle tipologie:||01 - Articolo su periodico|