Annals of internal medicine
-
The spinal tap, or lumbar puncture, has indisputable value; opinions differ, however, on the amount of that value. The procedure has variable utility depending on the clinical indications and the results of tests on the cerebrospinal fluid. ⋯ Because of the potential risk of the spinal tap, decisions about when to do the procedure must be made carefully. A probability analysis is provided to elucidate the usefulness of data from cerebrospinal fluid tests.
-
The activated partial thromboplastin time (APTT) and prothrombin time (PT) have three principal uses. In screening for coagulation disorders (or increased risk of postoperative hemorrhage), the tests add no information to the preoperative care of patients without clinical findings indicative of increased bleeding risk. Furthermore, the prevalence of asymptomatic congenital coagulopathies is so low that false-positive test results greatly outnumber true-positive results. ⋯ In evaluating abnormal bleeding, these tests are sufficiently sensitive that if both are negative, further investigation of the coagulation system is obviated. If one or both tests are positive, the pattern of results directs further attention to limited segments of the coagulation sequence. In monitoring anticoagulation therapy, the APTT and PT tests appear to contribute to the safety and effectiveness of heparin and warfarin therapies, respectively.
-
Fourteen patients with hypertrophic cardiomyopathy, 40 with aortic stenosis, and 4 with discrete subaortic stenosis had phonocardiograms during left heart catheterization that showed changes in the magnitude of the murmur in response to increases in the postextrasystolic gradient. All patients showed increases in the gradient of the left ventricular outflow tract during the postextrasystolic beat. ⋯ Only 2 of 7 patients with hypertrophic cardiomyopathy and resting gradients of more than 25 mm Hg had murmur increases. Our study shows that the systolic murmur in hypertrophic cardiomyopathy, unlike the outflow tract murmur in aortic stenosis or discrete subaortic stenosis, does not track consistently with the magnitude of the outflow tract gradient.