Respiratory changes during prolonged increased intra-abdominal pressure in pigs.
BACKGROUND
Increased intra-abdominal pressure (IAP) elevates thoracic pressure and airway pressures and reduces lung compliance in humans and laboratory animals. We studied respiratory alterations and arterial blood gas changes in pigs with IAP maintained at 20 mmHg or 30 mmHg for 3 h.


METHODS
Domestic pigs of both sexes weighing 30.0 +/- 5.1 kg (mean +/- SD) (n = 21) were divided into three groups. The animals were anesthetized and kept at 20 mmHg IAP (n = 7) or 30 mmHg IAP (n = 7) for 3 h. The third group (n = 7) served as control without an elevated IAP. We recorded respiratory alterations and changes in acid-based parameters at baseline and after 90 min and 180 min of increased IAP.


RESULTS
No significant hypoxia or hypercarbia was found in animals with an IAP of 20 mmHg IAP. At an IAP of 30 mmHg, pO2 decreased to an average 19.6 kPa and pCO2 increased to about 6 kPa, and the animals were slightly acidotic. Airway pressure increased significantly and lung compliance decreased in both groups of elevated IAP.


CONCLUSIONS
In our porcine model, an IAP of 20 mmHg or higher for 3 h is harmful for the respiratory function of the animals due to deterioration of respiratory parameters, increased airway pressure and decreased lung compliance.
Gudmundsson
F F
FF
Surgical Research Laboratory, Institute of Surgical Sciences, University of Bergen, Norway. ffgudmun@broadpark.no
Heltne
J K
JK
D000005:Abdomen / Q000503:physiopathology*; D000136:Acid-Base Equilibrium / Q000502:physiology; D000704:Analysis of Variance; D000768:Anesthesia, General; D000818:Animals; D001784:Blood Gas Analysis; D004195:Disease Models, Animal; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D007263:Infusions, Parenteral / Q000009:adverse effects; D007442:Intubation, Intratracheal; D007552:Isotonic Solutions / Q000008:administration & dosage; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D011312:Pressure / Q000009:adverse effects; D012129:Respiratory Function Tests; D012137:Respiratory System / Q000503:physiopathology*; D000077331:Ringer's Solution; D013552:Swine; D013990:Tidal Volume / Q000502:physiology; D013997:Time Factors
D006454:Hemoglobins; D007552:Isotonic Solutions; D000077331:Ringer's Solution