Cardiovascular Effects of Propofol in Dogs with Dilated Cardiomyopathy

Background: The authors tested the hypothesis that propofol improves left ventricular diastolic function in dogs with dilated cardiomyopathy by reducing left ventricular preload and afterload.

Methods: Seven dogs were instrumented for left ventricular and aortic pressures, aortic blood flow, and subendocardial segment length. Left ventricular afterload and contractility were quantified with aortic input impedance and preload recruitable stroke work, respectively. Diastolic function was evaluated with a time constant of left ventricular relaxation (tau); segment-lengthening velocities and time-velocity integrals during early left ventricular filling (dL/dtE and TVI-E, respectively) and atrial systole (dL/dtA and TVI-A, respectively); and a regional chamber stiffness constant (K). Dogs were paced at 240 beats/min for 18 +/- 3 days, and hemodynamics were recorded in sinus rhythm in the conscious state. Anesthesia was induced with propofol (5 mg/kg) and maintained with propofol infusions at 25, 50, and 100 mg [center dot] kg sup -1 [center dot] h sup -1, and hemodynamics were recorded after 15 min of equilibration at each dose.

Results: Propofol decreased mean arterial pressure, left ventricular end-diastolic pressure, and K but did not change heart rate. Propofol reduced total arterial resistance and increased total arterial compliance derived from aortic input impedance. Propofol also reduced preload recruitable stroke work. The lowest dose of propofol decreased tau. Propofol decreased dL/dtE and TVI-E and reduced the dL/dt-E/A and TVI-E/A ratios.     

Radiologic diagnosis of oat cell cancer in a high-risk screened population

A screening program of 10,040 cigarette-smoking men over 45 years of age was undertaken in an attempt to achieve earlier diagnosis, thereby increasing the cure rate, of oat cell lung cancer. Of the 155 men who were found to have lung cancer, 27 (17%) had confirmed oat cell cancer. Only one case was diagnosed at the first examination. The other 26 cases (called incidence cancer) were diagnosed by subsequent examinations. In 24 of the 26 patients, the tumor was not found until it was advanced (Stage III), and of these patients, only one is alive at 21 months follow-up. Two tumors were diagnosed as oat cell carcinoma at an early stage (Stage I), and both patients are alive with no evidence of disease at seven and 24 months. The screening program used in this study did not succeed in detecting oat cell cancer at an early stage.     

A study of incidence and relationship of intestinal metaplasia of gastric antrum and gastric metaplasia of duodenum in patients with nonulcer dyspepsia

The incidence and relationship of intestinal metaplasia of the gastric antrum and gastric metaplasia of the first part of the duodenum were studied in endoscopic biopsies from 120 patients with nonulcer dyspepsia. Intestinal metaplasia was present in 29% of antral biopsies and gastric metaplasia in 39% of duodenal biopsies, with 9% of patients having both. Intestinal metaplasia was not related to alcohol consumption, but was significantly higher in patients who smoked 10 cigarettes or more daily. (P<0.002). Gastric metaplasia was associated with duodenitis. Its incidence was significantly higher in males (P<0.001) and in patients with a history of high/moderate alcohol intake (P<0.02); these findings are reminiscent of the presence of a similar relationship between these factors and duodenal ulcers and support the suggestion that duodenitis and duodenal ulcers probably represent different parts of a single disease spectrum. The presence of both types of metaplasia in 9% of the patients suggest that factors other than gastric acidity may influence the development of metaplasia.Dr. S. Khan is supported by the Cancer Research Campaign.     

Controlled Ventilation Using the Lack Circuit with an Injector Device

A Lack breathing system with an injector device has been used for controlled ventilation. Oxygen was delivered through an injector device, which was positioned between the Lack circuit and the catheter mount, whilst nitrous oxide was delivered from the anaesthetic machine. The circuit was fully tested on two model lungs. Satisfactory tidal volumes were obtained and with fresh gas flow rates of about 4 l X min-1, rebreathing was not detected. The circuit was then studied on ten patients undergoing surgery and it was found that an end-tidal carbon dioxide concentration of 5-6% could be maintained. The use of this system during general anaesthesia is discussed.