Prior maximal exercise decreases pulmonary diffusing capacity during subsequent exercise.

Pulmonary diffusion (DLCO) increases during exercise due to greater pulmonary capillary volume (Vc) and membrane diffusing capacity (DM). However, after heavy exercise there is a reduction in resting DLCO. It is unclear whether this post-exercise effect will attenuate the normal increase in DLCO, Vc and DM during subsequent exercise and whether this affects SpO2 (pulse oximeter). DLCO, Vc, DM, cardiac output and SpO2 were measured at rest, moderate (~70% VO2peak) and heavy (~90 VO2peak) exercise in 9 subjects during 2 sessions separated by ~90 min. DLCO, Vc and DM increased during exercise (P<0.05). DLCO (P<0.05) and Vc (P<0.10), but not DM or SpO2 were lower in session 2 compared to the first. Reductions in DLCO and Vc appeared to be smallest during rest (1-4%) and greatest at high-intensity exercise (8-20%), but the interaction was not significant. SpO2 decreased by 4.9% and 5.1% from rest to high-intensity exercise during the first and second exercise bout, but these changes were not different. These data confirm that a bout of high-intensity exercise reduces DLCO and Vc, and may indicate that these changes are exacerbated during subsequent high-intensity exercise. Despite these changes, SpO2 was not affected by previous exercise.

Septic shock due to babesiosis.

We present the case of a 69-year-old man with an unremarkable past medical history and an intact spleen who developed shock and renal failure due to babesiosis. Despite hemodynamic parameters showing severe distributive shock with hyperdynamic cardiac function, the patient recovered fully after treatment with quinine sulfate and clindamycin.

Hypomagnesemic disorders.

Adequate magnesium stores are vitally important for life. Critically ill patients will almost always have diminished levels of circulating magnesium, and this predisposes them to a variety of adverse effects, some life threatening. The causes of hypomagnesemia are many and varied, but in the critically ill, losses from the kidneys, often secondary to medications and from the gastrointestinal (GI) tract, predominate. The measurement of magnesium is not straightforward, although many clinicians are now switching to the use of ionized magnesium from ion selective electrodes. The use of supplemental magnesium in acute flares of asthma has some support in medical literature, especially for those patients with severe disease who fail traditional therapy. Magnesium holds the preeminent position in the treatment of pre-eclampsia and eclampsia in the minds of most obstetricians, who have decades of experience showing it to be both effective and safe. Magnesium is clearly useful for certain types of ventricular tachycardia, and probably assists in the treatment of several types of supraventricular tachycardia. Its role in acute myocardial ischemia is less certain, although there is no benefit once reperfusion therapy has already been carried out. Finally, the role of magnesium in the treatment of acute cerebral insults is an exciting area of active investigation with initial studies suggesting much promise.

Managing the unstable patient. The first 10 minutes often set the course.

Some patients die shortly after the onset of an acute illness, despite the best of care. However, a well-led well-organized approach during the first 10 minutes of care can greatly improve the chances of survival and minimize subsequent morbidity. Early treatment should emphasize proper airway management, adequate intravenous access, and a thoughtful approach to the use of medications.

Pyogenic arthritis complicating varicella infection.

Arthritis has not previously been reported as a complication in adult patients with chickenpox. In pediatric patients, the arthritis that complicates chickenpox is most commonly aseptic but does rarely result from bacterial infection. We report the case of a 21-year-old man who developed acute monoarticular septic arthritis due to Lancefield Group A beta-hemolytic streptococci. Despite the more common viral cause of arthritis in pediatric patients, physicians should not attribute arthritis associated with varicella in adults to a viral cause without diagnostic arthrocentesis.

Prolonged recurrence of pentamidine-induced torsades de pointes.

OBJECTIVE: To report a case of recurrent pentamidine-induced torsades de pointes (TdP) and to review previously reported cases in the literature. DATA SOURCES: Medical records of the subject patient, case reports, and relevant studies identified by MEDLINE. DATA EXTRACTION: Data were abstracted from pertinent published sources by one author and reviewed by the remaining authors. DATA SYNTHESIS: A 43-year-old woman with AIDS experienced pentamidine-induced TdP. TdP and other cardiac arrhythmias recurred repeatedly for 13 days after pentamidine therapy was discontinued and in the presence of normal magnesium and potassium serum concentrations. Infusions of magnesium, lidocaine, and isoproterenol were used to treat the arrhythmias. The exact mechanism of pentamidine-induced TdP has not been clearly established. It is postulated, however, that the similarity of pentamidine's structure to procainamide may contribute to its proarrhythmic effects. The tissue-binding capacity of pentamidine may result in a prolongation of its effects. No distinctive characteristic appears to predispose people to the development of cardiac arrhythmias. Laboratory values that should be monitored include serum magnesium, potassium, and creatinine. The corrected QT interval also should be monitored. CONCLUSIONS: Recurrent arrhythmias may be seen for many days after intravenous administration of pentamidine has been discontinued. Clinicians should consider this phenomenon as they decide how to monitor patients who have received this drug.