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Biomedical subjects

J Boon

Publications and source records attributed to J Boon.

35 records · Page 2Linked to original sources
PubMed1986

Ventilatory response to CO2 in infants with alleged sleep apnoea.

Twenty-eight children whose parents reported sleep apnoea were investigated. In 15 infants apnoeic periods during sleep could be confirmed during clinical observation. Ventilatory responses to CO2 were measured in all infants, in 23 during sleep in 5 only when awake. A very wide range of CO2 sensitivities was found. In four children there was no ventilatory response or even a paradox one: a decrease in ventilation as PACO2 was increased. Two of these non-responding children died later, one still sleeps in a respirator aged three, and one developed a normal CO2 sensitivity a few months later. It is concluded that the parent's account of an apnoeic incident during sleep is not always reliable. A ventilatory response to CO2 is a useful tool with which to identify infants at risk of death, possibly related to a defective control of ventilation. The actual value of the CO2 sensitivity hardly gives any useful information, due to the wide range of "normal" reactions. No or negative ventilatory responses to CO2 seem to be indicators of high risk children, and may possibly play a role in SIDS incidents.

Carbon Dioxide↗
PubMed1982

Echocardiographic assessment of mitral valve motion, cardiac structures, and ventricular function in dogs with atrial fibrillation.

Eleven dogs with atrial fibrillation were examined echocardiographically. During atrial fibrillation, there was no evidence of atrial contraction in the left ventricle or aorta, or on the mitral valve leaflets. Measurement of cardiac structures in echocardiograms showed decreased sizes for the aorta (P less than 0.01), interventricular septum (P less than 0.01), and posterior left ventricular wall (P less than 0.02). Evidence of decreased contractility of the left ventricle was noticed with the decreased amplitude of motion of the posterior left ventricular wall (P less than 0.001) and decreased fractional shortening (P less than 0.01). Not every QRS resulted in systolic or diastolic motion in the mitral and aortic valve leaflets, thus helping to account for the pulse deficits normally seen during atrial fibrillation.

Animals↗
PubMed1981

Postinfusion thrombophlebitis: effect of intravenous drugs used in anaesthesia.

The method of sequential analysis was used to investigate the effect of injection of anaesthetic drugs into an intravenous infusion line on the incidence of thrombophlebitis in the 48 hours following surgery. Analysis of the results failed to show that anaesthetic drugs increased the incidence of thrombophlebitis (P = 0.05), and further showed that they were not a causative factor (P = 0.15).

Adult↗
PubMedDate not supplied

Idiopathic dilated cardiomyopathy in dogs: survival and prognostic indicators.

To further define the prognosis and identify clinical findings predictive for survival in dogs with dilated cardiomyopathy (DCM), we performed Kaplan Meier survival analysis of 37 dogs with idiopathic DCM. Survival analysis showed that the 50% probability of survival occurred at 2.3 months. Probability of survival at 1 year was 37.5% and at 2 years was 28%. Bivariate Cox proportional hazard ratios identified pleural effusion and pulmonary edema, both signs of congestive heart failure, as independent prognostic indicators for dogs with DCM (P < .01). Hazard ratios for these prognostic indicators were 2.354 and 3.291, respectively. Multivariate Cox stepwise regression identified pleural effusion, left ventricular free-wall thickening fraction, ventricular ectopy, and weight loss as significant prognostic indicators for dogs with DCM. Because of the retrospective nature of this study, the effects of different drug treatments were not evaluated. The type of cardiac-related death, progressive failure versus sudden death, was not addressed in this study and requires further evaluation.

Animals↗
PubMedDate not supplied

Clinical characteristics of 53 dogs with Doppler-derived evidence of pulmonary hypertension: 1992-1996.

Pulmonary hypertension occurs as a primary or secondary disorder of the pulmonary vasculature. Doppler echocardiography provides a noninvasive tool for the estimation of pulmonary arterial pressure when tricuspid regurgitation or pulmonic insufficiency is present. The cardiology database at Colorado State University was reviewed, and echocardiographic records from cases diagnosed with pulmonary hypertension were evaluated. Application of the modified Bernoulli equation to the maximal instantaneous velocity of a right-sided regurgitant jet provided evidence of pulmonary hypertension in 53 dogs over a 4-year period. Tricuspid regurgitant velocity > or = 2.8 m/second or pulmonic insufficiency velocity > or = 2.2 m/second was considered abnormal and indicative of pulmonary hypertension. Tricuspid regurgitant gradients in 51 dogs ranged from 32 to 145 mm Hg (mean, 63.0 mm Hg; median, 57.0 mm Hg; 25th-75th percentiles, 45.2-76.5 mm Hg). Pulmonic insufficiency gradients in 8 dogs ranged from 20 to 100 mm Hg (mean, 59.5 mm Hg; median, 61.5 mm Hg; 25th-75th percentiles, 32.0-84.5 mm Hg). Affected dogs ranged in age from 2 months to 16 years. Clinical signs were characteristic of cardiopulmonary disease, but a relatively high frequency of syncope was noted (12 of 53 dogs, 23%). Pulmonary hypertension was probably due to increased pulmonary vascular resistance in 23 dogs, pulmonary overcirculation in 2 dogs, and pulmonary venous hypertension in 23 dogs. Five dogs lacked a clinically recognizable cardiopulmonary cause of pulmonary vascular disease. Our results suggest that pulmonary hypertension can occur as a complication of commonly encountered cardiopulmonary diseases, and that Doppler echocardiography can facilitate recognition of this condition.

Animals↗