Tumor necrosis factor depresses myocardial contractility in endotoxemic swine.

BACKGROUND: Depression of myocardial contractility occurs in septic shock. METHODS: Fourteen pigs were instrumented to measure cardiopulmonary dynamics after a challenge of Escherichia coli endotoxin (lipopolysaccharide endotoxin, LPS). A volumetric Swan-Ganz catheter was placed via the jugular vein, and a carotid arterial line was placed into the aortic root. Eight pigs received LPS alone and six pigs received tumor necrosis factor monoclonal antibody (TNF MAb) 15 minutes before the administration of LPS. Pulmonary artery and aortic root blood were sampled for amounts of TNF. Ninety minutes after LPS administration, thoracotomy was performed to biopsy the right and left ventricles for TNF levels. Contractility was determined from the end systolic pressure-volume relationships of pressure-volume diagrams. RESULTS: Right ventricular end diastolic volume index nearly doubled and myocardial contractility decreased by 40% from baseline in the pigs receiving only LPS. Pigs that received TNF MAb had no change in myocardial contractility or right ventricular end diastolic volume index from baseline. There was a higher level of TNF in the aortic sample than in the pulmonary samples at 60 minutes. Right ventricular tissue TNF levels were significantly higher in the LPS-alone group. There was no such difference in left ventricular tissue. CONCLUSION: The left and right ventricles have different susceptibilities to TNF MAb. TNF may decrease myocardial contractility in sepsis. Blockade of TNF with TNF MAb reverses the depression of myocardial contractility and the right ventricular dilatation associated with septic shock.

Impairment of cardiac performance by laparoscopy in patients receiving positive end-expiratory pressure.

BACKGROUND: The cardiopulmonary effects of the combination of abdominal and thoracic pressures in humans have not been well delineated. OBJECTIVE: To study the cardiopulmonary effects of 15 mm Hg of intra-abdominal pressure in the presence and absence of 10 cm H20 of positive end-expiratory pressure (PEEP). DESIGN: Prospective. SETTING: University hospital. METHODS: Nine patients undergoing laparoscopic cholecystectomy had pulmonary compliance, cardiac output, exhaled carbon dioxide, and preload (left ventricular end-diastolic volume) determined at 4 points while undergoing ventilation with (1) no PEEP before pneumoperitoneum; (2) 10 cm H20 of PEEP and no pneumoperitoneum; (3) no PEEP and 15 mm Hg of pneumoperitoneum; and (4) 10 cm H20 of PEEP and 15 mm Hg of pneumoperitoneum. Preload and cardiac output were determined by means of transesophageal echocardiography. Pulmonary compliance and exhaled carbon dioxide were determined by an attachment to the end of the endotracheal tube. MAIN OUTCOME MEASURES: Preload, cardiac output, exhaled carbon dioxide, and pulmonary compliance. RESULTS: There was no significant change from baseline in preload, cardiac output, or pulmonary compliance when either PEEP or pneumoperitoneum was applied separately. However, there was a significant decrease in preload (P<.01), cardiac output (P = .01), and exhaled carbon dioxide (P =.04) when PEEP and pneumoperitoneum were applied together. Pulmonary compliance was not significantly affected at any of these points. CONCLUSIONS: There was a significant reduction in preload and cardiac output when there was intra-abdominal pressure of 15 mm Hg in the presence of 10 cm H20 of PEEP. This combination of pressures may pose a contraindication to laparoscopic surgery.

Right ventricular volumes overestimate left ventricular preload in critically ill patients.

BACKGROUND: Studies have shown right ventricular end-diastolic volume (RVEDV) to be a more accurate estimate of left ventricular preload than pulmonary artery wedge pressure. We prospectively evaluated the ability of RVEDV to predict left ventricular end-diastolic volume (LVEDV) in critically ill patients. METHODS: Thirty critically ill patients in the surgical intensive care unit underwent concurrent measurement of RVEDV and LVEDV. RVEDV was measured using a residual fraction Swan-Ganz catheter (RF Swan). LVEDV was measured using transesophageal echocardiography with acoustic quantification. Intracardiac, intra-abdominal, and ventilatory pressures were also measured. RESULTS: RVEDV as measured by the RF Swan was significantly larger (by a factor of 2) than LVEDV (p < 0.0001 analysis of variance). However, the RVEDV and LVEDV were strongly correlated (r = 0.71, p < 0.0001, Pearson's correlation). CONCLUSIONS: RVEDV from the RF Swan markedly overestimated left ventricular preload. If RVEDV is used as an absolute value for determining preload, patients may be underresuscitated. Transesophageal echocardiography in conjunction with RF Swan can be used to more accurately determine preload and cardiac performance than RF Swan alone in critically ill patients.

Isolated blunt rupture of the infrarenal inferior vena cava: the role of ultrasound and computed tomography in an occult injury.

A case of isolated blunt rupture to the infrarenal vena cava secondary to assault is reported. This case report is presented to heighten awareness of an unusual presentation of this potentially lethal injury and to emphasize that diagnostic modalities may offer subtle or indirect indications of an injury that, when coupled with clinical signs and symptoms, prompt surgical intervention necessary for patient salvage.

Arterial occlusion and progressive gangrene caused by mucormycosis in a patient with burns.

Ischemic necrosis of the upper extremities caused by invasive mucormycosis developed in a patient with soil contamination of severe burn wounds. An arteriogram of the arm showed complete obstruction of blood flow in the forearm. Histologic specimens showed nonseptate branching hyphae obliterating the arterial lumens. Cutaneous mucormycosis affects patients who are immunocompromised, including victims of multiple trauma and burns. This case represents a previously undescribed clinical presentation in a patient with major burns. Because of its lethal nature, mucormycosis in a patient with burns must be treated with aggressive surgical debridement, including amputation, and with parentral amphotericin B at the earliest sign of cutaneous presence.