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\s=b\ We studied the effects of laparoscopic cholecystectomy on respiratory and hemodynamic function in eight adult pigs. Minute ventilation was adjusted to normalize baseline arterial blood gases, then fixed throughout carbon dioxide insufflation. A metabolic measurement cart recorded total CO2 excretion, oxygen consumption, and minute ventilation. Carbon dioxide pneumoperitoneum was maintained at a constant pressure of 15 mm Hg as cholecystectomy was performed. After 1 hour of insufflation, CO2 excretion increased from 115\m=+-\10mL/min to 149\m=+-\9mL/min but O2 consumption remained unchanged. The PaCO2 increased from 35\m=+-\2mm Hg to 49\m=+-\3mm Hg and arterial pH fell from 7.47\m=+-\0.02to 7.35\m=+-\0.03. Systemic and pulmonary hypertension occurred and stroke volume dropped from 35.5\m=+-\3.5mL to 28.6\m=+-\2.2mL with compensatory tachycardia. Right atrial pressure remained unchanged as inferior vena cava pressure increased to reflect the intraperitoneal pressure. We conclude that CO2 pneumoperitoneum resulted in significant transperitoneal CO2 absorption, with secondary hypercapnia and acidemia. The accumulation of CO2 was also associated with an increase in systemic and pulmonary arterial pressure. Heart rate increased to compensate for the decreased stroke volume to maintain cardiac output. (Arch Surg. 1992;127:928-933) Laparoscopi e cholecystectomy is a recent, but exciting, . development in the surgical management of chole¬ lithiasis, as it removes the target organ and yet, avoids the traditional large upper abdominal incision with the asso¬ ciated postoperative pain, disability, and slow return to work. Since the first procedure was performed in France in 1987, laparoscopie cholecystectomy has become popular in the United States.1-2 Although the procedure has enjoyed a minimal morbidity similar to that of open cholecyst¬ ectomy,2"4 reports on complications with ventilatory status such as hypercapnia or acidemia have appeared. Critical analysis of our experience with the first 381 patients at the University of California Davis Medical Center, Sacra¬ mento, and its affiliated hospitals revealed a comparable mortality and morbidity with the open procedure. Techni¬ cal complications occurred in 2% of the patients; nontech¬ nical complications occurred in 4% of patients. The most common nontechnical complication was atelectasis or pneumonia in five patients. One patient with a history of chronic obstructive pulmonary disease experienced severe hypercapnia following intraperitoneal carbon dioxide in¬ sufflation. She was subsequently converted to an open procedure owing to technical reasons, but the hypercapnia persisted postoperatively, requiring 24 hours of mechan¬ ical ventilation.5 Wittgen et al6 also reported that patients with preoperative cardiac or pulmonary disease experi¬ enced significant accumulation of arterial C02 and devel¬ opment of acidemia during the C02 insufflation period. One of these patients also required conversion to open cholecystectomy because of refractory acidemia.6 Liu et al...

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Prostaglandins F2 alpha, E2, and I2 (as 6-keto-PGF1 alpha) and TxA2 (as TxB2) were measured by radioimmunoassay in plasma and lymph from 12 conscious sheep with chronic lung lymph fistulas given Escherichia coli endotoxin (2-10 micrograms/kg) and followed for 24 h. Endotoxin produced a two-phase pulmonary injury. Phase 1 was characterized by transient severe pulmonary hypertension and increased lymph flow rate (QL). Plasma and lymph PGF2 alpha concentrations increased from base-line values of 0.13 +/- 0.08 and 0.30 +/- 0.10 ng/ml to 0.96 +/- 0.37 and 2.8 +/- 0.80 ng/ml, respectively. Values for TxB2 increased from 0.7 +/- 0.1 to 5.5 +/- 1.1 ng/ml in lymph and to 3.2 +/- 0.6 in plasma. Plasma PGI2 increased from 0.48 +/- 0.29 to 4.97 +/- 1.21 ng/ml and lymph PGI2 from 1.80 +/- 0.73 to 14.19 +/- 2.79 ng/ml. Phase 2 was characterized by moderately elevated pulmonary vascular pressures and a maintained high flow rate of protein-rich lymph. Lung lymph and plasma PGF2 alpha concentrations returned to base line. Lymph PGI2 decreased significantly to 5.23 +/- 2.47 ng/ml, whereas plasma PGI2 decreased to 2.70 +/- 1.07 ng/ml. We conclude that prostaglandins, particularly PGF2 alpha and prostacyclin, are released from the lung after endotoxemia and appear in lung lymph as sensitive indicators of pulmonary microvascular injury. Prostanoid production appears to temporally correspond with changes in the pulmonary microcirculation.

The objective of this investigation was to study the effects of the first marketed haemoglobin-based oxygen carrier, Hemoglobin glutamer-200 (bovine) (Hb-200) (Oxyglobin) on splanchnic perfusion and oxygenation in a canine model of acute hypovolaemia. Twelve anaesthetized dogs [mean weight 30.8 (S.D. 1.4) kg] were instrumented for recordings of heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), cardiac output and cranial mesenteric arterial (CMA) and venous blood flows (CMV). Total and plasma haemoglobin (Hb), oxygen content and saturation, lactate concentration, pH and blood gases were analysed in arterial, mixed venous and mesenteric venous blood samples. Measurements were made before (baseline) and after 1 h of haemorrhage, after which animals were resuscitated with either shed blood (controls) or Hb-200 until HR, MAP and CVP returned to prehaemorrhage levels. Recordings were repeated immediately and 3 h after termination of fluid resuscitation, after which organ specimens were obtained for microscopic examination. Haemorrhage (average 32 ml kg(-1)) reduced MAP to 50 mm Hg, increased HR and systemic vascular resistance (SVR), and was accompanied in both the systemic and the splanchnic circulation by significant decreases in blood flow, Hb content and oxygen delivery (DO2), and lactic acidosis. In controls, all variables recovered to baseline after isovolaemic resuscitation with shed blood. In dogs resuscitated with a small volume of Hb-200 (10 ml kg(-1)), HR, MAP, CVP and CMA and CMV blood flows returned to baseline. However, cardiac output, total Hb, oxygen content and systemic and mesenteric DO2 remained depressed while SVR increased further. Mesenteric and systemic acid-base status recovered in both groups, and there was no difference in microscopic tissue damage between groups. Thus, Hb-200 reconstituted splanchnic perfusion and oxidative metabolism in spite of pronounced systemic vasoconstriction and insufficient restoration of CO and DO2; it may improve diffusive oxygen transport in the microvasculature by virtue of haemodilution and its high efficiency in the uptake and release of oxygen.