Lack of lung hemorrhage in humans after intraoperative transesophageal echocardiography with ultrasound exposure conditions similar to those causing lung hemorrhage in laboratory animals.

This study investigated the phenomenon of ultrasonically induced lung hemorrhage in humans. Multiple experimental laboratories have shown that diagnostic ultrasound exposure can cause hemorrhage in the lungs of laboratory animals. The left lung of 50 patients (6 women, 44 men, mean age 61 years) was observed directly by the surgeon after routine intraoperative transesophageal echocardiography was performed. From manufacturer specifications the maximum derated intensity in the sound field of the system used was 186 W/cm2, the maximum derated rarefactional acoustic pressure was 2.4 MPa, and the maximum mechanical index was 1.3. The lowest frequency used was 3.5 MHz. This exposure exceeds the threshold found for surface lung hemorrhage seen on gross observation of laboratory animals. No hemorrhage was noted on any lung surface by the surgeon on gross observation. We conclude that clinical transesophageal echocardiography, even at field levels a little greater than the reported thresholds for lung hemorrhage in laboratory animals, did not cause surface lung hemorrhage apparent on gross observation. These negative results support the conclusion that the human lung is not markedly more sensitive to ultrasound exposure than that of other mammals.

A personal experience in comparing three nonoperative techniques for treating internal hemorrhoids.

Infrared photocoagulation therapy was used on a total of 302 patients. Approximately 20% of the patients experienced minor bleeding; however, two required surgery, and 30% of the patients experienced discomfort during a 14-day period following the procedure. Good results were obtained in patients with first- and second-degree hemorrhoids. Heater probe coagulation therapy was conducted in a total of 264 patients. Good results were achieved in 90% of patients with first- and second-degree hemorrhoids, minor pain and bleeding occurred in approximately 10% of these patients, and one patient with third-degree hemorrhoids who was treated with this technique failed to respond and required surgery. Ultroid d.c. current therapy was utilized in 192 patients, and follow-up results were good in 95% of these cases. Minor bleeding occurred in four patients. It is concluded that all three techniques, performed on an outpatient basis with little or no sedation, are effective modalities for first- and second-degree hemorrhoids, but that Ultroid d.c. current therapy is associated with less discomfort and fewer complications and that Ultroid therapy may yield good results in some patients with third- or even fourth-degree hemorrhoids.

Can we trust the direct radial artery pressure immediately following cardiopulmonary bypass?

Reversal of the usual relationship between aortic and radial artery pressure can occur in patients following cardiopulmonary bypass. Radial systolic (and often radial mean) pressures were lower, relative to aortic pressure, after cardiopulmonary bypass than before bypass in all 18 patients studied. The systolic pressure difference (aortic minus radial) was large enough to be of clinical concern (12-32 mmHg) in 13 patients. The change persisted for 10-60 min, gradually returning toward normal. The change temporally was associated with warming at the end of cardiopulmonary bypass and lowered forearm vascular resistance. Relative forearm vascular resistance (x) predicted the systolic aortic minus radial pressure difference (y) by the equation y = -0.34x + 17 for all patients (r = -0.49, P less than 0.001). The authors conclude that radial artery pressure does not accurately reflect central aortic pressure in the immediate postbypass period.