Primary aortoenteric fistula: computed tomographic diagnosis of an atypical presentation.

A primary aortoenteric fistula is a potentially devastating complication of untreated aortic aneurysmal disease. The clinical presentation can be confusing, leading to a delay in diagnosis. Computed tomography (CT) can greatly assist in establishing the diagnosis. An unusual case of a primary aortoenteric fistula with an atypical presentation is described. The patient presented with symptoms indicating an exacerbation of recurrent nephrolithiasis. No clinical history of an abdominal aortic aneurysm or previous history of gastrointestinal hemorrhage was reported. A CT scan demonstrated extravasation of arterial contrast into the duodenum. The aorta was repaired with an in-line prosthetic graft. A review of the literature regarding this rare entity and surgical options are presented.

Comparative stress hormone changes during helium versus carbon dioxide laparoscopic cholecystectomy.

Laparoscopic surgery has been termed minimally invasive surgery by advocates of this technology. It has been demonstrated previously that using carbon dioxide for insufflation produces a respiratory acidosis due to transperitoneal absorption of gas. Insufflation with helium does not create this acidosis. We questioned whether laparoscopic surgery would elicit a stress response and whether the absence of acidosis with helium might prevent or reduce the levels of stress hormones. Sixteen female patients undergoing laparoscopic cholecystectomy were randomly assigned to helium (n = 8) or CO2 (n = 8) insufflation. Serum cortisol, epinephrine, and norepinephrine were measured preoperatively, after induction of anesthesia but before insufflation, at 45 min of surgery, and after desufflation. There were increases in epinephrine, norepinephrine, plasma cortisol, and urine cortisol at 45 min and at the conclusion of the procedure over the preoperative value. With ANOVA, each variable showed significant increases from preoperative values, at 45 min, and at the end of the case. Except for the increased epinephrine when helium was used, there were no significant differences in the other variables between helium and CO2. Laparoscopic cholecystectomy produces significant increases in stress hormone levels. Prevention of acidosis with helium insufflation does not appear to protect against increases in stress hormones. Epinephrine levels with helium insufflation are higher than with CO2, and elevations in stress hormones suggest that laparoscopic cholecystectomy is not physiologically minimally invasive.

Tissue oxygenation in hypovolemic shock.

Bowel mucosal ischemia may be related to the development of systemic sepsis. Traditional indices of oxygen metabolism are flow-weighted averages which do not reflect tissue-specific oxygen concentration. We undertook this study to examine the relationship between systemic oxygen delivery (DO2) and tissue oxygen tension (TPO2) in hypovolemic shock. A modified Wiggers model was used to produce hypotension in five swine. TPO2 was measured continuously with fluorescence-quenching 1-mm probes placed in the submucosa of the terminal ileum and subcutaneously in an axillary fold. Shock was maintained for 1 hr, followed by resuscitation. Cardiac output, systemic and pulmonary arterial pressures, and arterial and mixed venous blood gases were measured every 15 min. Data were analyzed by nonparametric ANOVA and rank coefficients, with logarithmic curve fitting and linear regression. DO2 decreased with phlebotomy (P < 0.003) as did skin TPO2 (P < 0.001) and bowel TPO2 (P < 0.0004). Skin and bowel TPO2 varied with DO2 and each other (P < 0.05). TPO2 remained low throughout the shock period and returned to or exceeded baseline levels with resuscitation (P < 0.05). The following were concluded: (1) Hypovolemic shock produces a significant and rapid decrease in subcutaneous and bowel TPO2 with concomitant change in DO2. (2) The degree of bowel ischemia, clinically inaccessible for quantitation, is paralleled by subcutaneous TPO2. (3) TPO2 provides information about oxygen availability in shock and resuscitation not available from traditional parameters of oxygen transport.

Helium insufflation for laparoscopic operation.

Laparoscopic surgical procedures are becoming simultaneously more commonplace and complex. However, carbon dioxide (CO2) pneumoperitoneum required for these procedures causes a respiratory acidosis. We undertook this study to determine if an alternate insufflating gas, such as helium, prevents this sequelae. Twenty patients undergoing elective laparoscopic cholecystectomy were randomized to receive either CO2 or helium insufflation. Intraoperative parameters, including arterial CO2 (PaCO2), end-tidal CO2, pH, bicarbonate (HCO3-), cardiac output and blood pressure were obtained before, during and at the conclusion of pneumoperitoneum. Effects of the two gases on these variables were compared. The average CO2 rose significantly from 35.7 +/- 1.0 to 50.4 +/- 3.2 (p < 0.0001), while pH decreased from 7.434 +/- 0.014 to 7.286 +/- 0.018 (p < 0.0001) in those who received CO2. No change in PaCO2 was observed in those who received He, although a small decrease in pH from 7.428 +/- 0.011 to 7.392 +/- 0.012 (p < 0.05) was observed. HCO3- decreased slightly in both groups. Increases in blood pressure and pulse rate were independent of the gas received. The cardiac output did not change. Helium insufflation for laparoscopic cholecystectomy does not produce the respiratory acidosis caused by CO2 and, therefore, merits further investigation for use, particularly in patients with underlying respiratory disease.