Lawn mower injuries: a case report.

Frequent and varied injuries are sustained during the operation of power lawn mowers in the United States. A description of one such injury leading to cardiac trauma is presented. The clinical signs of injury were initially unclear, and obtaining accurate historical data was vital in the diagnosis of this patient.

Left upper lobe torsion following lower lobe resection. Early recognition of a rare complication.

Left upper lobe torsion occurred in a woman during the first 24 hours following left lower lobectomy for bronchogenic carcinoma resection. To our knowledge, this is the first report of left upper lobe torsion. When atypical chest pain or opacification of the remaining lung develops following resectional surgery, torsion of the remaining lung must be suspected. Prompt diagnosis and treatment may prevent the morbidity and mortality associated with pulmonary infarction from torsion.

When should the hypoplastic right ventricle be used in a Fontan operation? An experimental and clinical correlation.

Eight anesthetized dogs underwent closure of the tricuspid valve and a Fontan procedure, and the right ventricular cavity was reduced in stepwise fashion. There was an increase in right atrial pressure from 9.3 +/- 2.2 to 14.1 +/- 2.4 mm Hg (p less than 0.001), a decrease in pulmonary artery pulse pressure from 10.8 +/- 2.2 to 6.8 +/- 2.2 mm Hg (p less than 0.01), and a decrease in cardiac index from 2.7 +/- 0.3 to 2.2 +/- 0.2 L/min/m2 (p less than 0.001) when the ventricular size was dropped from 50% to 25% of normal. The difference between mean pulmonary artery pressure and mean right atrial pressure, which reflects the positive stroke work index of the ventricle, disappeared once the right ventricular cavity was reduced to 25% of normal (15.0 +/- 6.1 versus 14.1 +/- 2.4 mm Hg; p = not significant). Experimental results were correlated with postoperative catheterization data from 19 patients with tricuspid atresia who had the Fontan operation. Mean right atrial pressure was 18 +/- 4.6 mm Hg and cardiac index was 2.35 +/- 0.65 L/min/m2 in patients with a direct atrium-pulmonary artery anastomosis or an atrioventricular anastomosis with a right ventricular cavity less than 30% of normal versus 13 +/- 3.2 mm Hg and 3.42 +/- 0.46 L/min/m2 for those with an atrioventricular connection and a right ventricular cavity greater than 30% of normal (p less than 0.05 and p less than 0.02, respectively). The right ventricle enlarged from 27% +/- 6% of normal preoperatively to 35% +/- 10% of normal on follow-up (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Management of recurrent coarctation of the aorta: a new experimental technique.

A new technique is described for the management of recurrent coarctation of the aorta. It involves enlarging the narrowed segment by an onlay patch sutured to the adventitia and outer media of the aortic wall. The procedure was used in 6 mongrel dogs with preexisting surgically created coarctation. Aortic cross-clamping time ranged between 7.5 and 11 minutes (mean, 8.8 +/- 1.3 minutes). There were no operative deaths or complications. Gross and microscopic examination of the aorta 6 to 12 months (mean, 9 +/- 2.2 months) postoperatively revealed a 290 to 380% (mean, 350 +/- 30%) increase in the diameter of the repaired area and no evidence of thrombosis or pseudoaneurysm formation. The need for minimal dissection and the brief period of aortic cross-clamping make this approach an attractive alternative in the surgical treatment of patients with difficult cases of recoarctation.

Factors influencing coronary vascular resistance during hypothermia.

Factors influencing total coronary vascular resistance (CVR) during hypothermia were studied in 30 mongrel dogs. Complete isolation of the heart in situ was achieved by transection of all cardiac neural and vascular connections in 15 dogs (denervated, Group I). Cardiac innervation was maintained in the other 15 dogs using systemic normothermic cardiopulmonary bypass (innervated, Group II). The aortic root was perfused with heparinized oxygenated blood at a constant flow rate at variable myocardial temperatures. Electromechanical arrest was achieved using potassium chloride (KCl) (25 meq/liter) added to the coronary perfusate. In each group, 5 dogs were maintained at a flow rate of 10 cc/kg/min without KCl and allowed to beat spontaneously, another 5 at a flow rate of 10 cc/kg/min and arrested with KCl, and the remaining 5 at a flow rate of 5 cc/kg/min with KCl. Total coronary vascular resistance was calculated from aortic root pressure, right atrial pressure, and flow rate and expressed in units per 100 grams of cardiac tissue. At 37 degrees C, resistance was lower in the denervated arrested (1.3 +/- 0.2) than in the innervated arrested hearts (2.1 +/- 0.2) (P less than 0.001). Preservation of spontaneous electromechanical activity in the innervated hearts resulted in a lower resistance (0.4 +/- 0.1) (P less than 0.001). A progressive decrease in myocardial temperature to 15 degrees C resulted in a corresponding decrease in coronary vascular resistance to a plateau value (0.5 to 0.7 U) in all arrested groups. The data suggest that at normothermia, innervation increases vascular tone in the coronary vascular bed, while electromechanical activity decreases it.(ABSTRACT TRUNCATED AT 250 WORDS)

Ruptured thoracic aneurysm: unusual manifestation and early diagnosis using CT.

Rupture of a thoracic aortic aneurysm across the posterior mediastinum into the right side of the chest is rare. The diagnosis may be delayed by the absence of expected findings in the left side of the chest. We recently encountered two patients with thoracic aneurysm rupture who came to medical attention initially because of right-sided pleural and/or extrapleural hematomas, which were accurately diagnosed preoperatively on the basis of computed tomography (CT) findings. Aortography, performed in one patient, added no useful information. Because CT accurately identifies the presence of pleural or extrapleural blood, as well as the underlying aneurysm or dissection, CT should be the first examination performed in cases of suspected thoracic aneurysm rupture.