Hemodynamics of heartworm infection.

To determine the hemodynamic responsiveness of dogs testing positive for heartworms (direct blood smear), we compared the response of control and heartworm-infected animals to stellate stimulation (SS). Using the anesthetized, open-chest model, twenty dogs (10 control and 10 heartworm-positive) were instrumented to measure left ventricular pressure (LVP), arterial pressure (AP), and coronary flow velocity (CFV) of the left circumflex coronary artery. CFV was converted to flow per gram tissue (CBFG) by weighing the perfusion area of the circumflex artery. The average wet weight of the worm mass infecting the dogs was 1.0 +/- 0.1 g, which represented an average of 5% of the right ventricular free wall weight. Overall heart size and right ventricular weights were greater in the heartworm-positive animals, as well as heart weight to body weight ratios. Prior to SS, LVP was the same for both groups. However, dP/dt and CBFG were 21% and 19% lower, respectively, in the heartworm-positive animals. Stellate stimulation sufficient to produce a 30-mmHg rise in AP led to 25%, 13%, and 40% increases in LVP, dP/dt, and CBFG, respectively, in the control animals. Increases of 22%, 10%, and 52% in the same parameters were observed in the heartworm-positive animals. Although control dP/dt and CBFG in the heartworm-positive animals were lower than in the heartworm-negative animals, heartworm infection at this level did not hinder myocardial responsiveness to SS.

Foreign body aspiration: experience at the University Pediatric Hospital.

Fifty eight patients were admitted to the University Pediatric Hospital with the diagnosis of foreign body aspiration from August 1986 to January 1991. Of this 58 admissions, 40 records were analyzed for incidence, clinical and radiological manifestations, morbidity and nature of the foreign material in an effort to compare our findings with those of other centers, including another previous study in our institution. Our data reveals that the event of aspiration of a foreign body was most common between 1 to 2 years of age, this comprises 18 (45%) of the cases; male to female ratio was 1:3; 17 (42.5%) cases were diagnosed during the first 24 hours of the event and another 42.5% were diagnosed after 48 hours. Coughing and a choking episodes were the most common signs of presentation with hyperaeration of the lung as the main radiological finding. The left main stem bronchus as the lodgement site and the peanut as the foreign object were the most common findings. The mortality ratio was 7.5%. It is important to make parents and health providers aware of patients at risk and knowledge of basic life support measures.