Bi-level noninvasive ventilation (NIV) in patients with obesity hypoventilation syndrome (OHS) can help reverse left ventricular hypertrophy, according to a study from Spain. Patients with OHS treated with continuous positive airway pressure (CPAP) did not experience the same benefits. Bi-level NIV (commonly referred to by its most popular trade name, BiPAP) is known to improve pulmonary [… read more]
The U.S. FDA is warning physicians against prescribing the antibiotic clarithromycin to patients with coronary artery disease. In long-term follow up of a randomized controlled trial, there was an unexpectedly higher rate of death in patients who received a two-week treatment course of clarithromycin, compared to placebo. FDA has added a new warning to clarithromycin’s [… read more]
People with chronic obstructive pulmonary disease (COPD) had an increased rate of heart attacks and strokes in the first month after starting long-acting inhaled bronchodilators. That’s the conclusion of an observational study from Taiwan, published in JAMA Internal Medicine. Researchers analyzed data on 284,220 Taiwanese adults with COPD who had never used bronchodilators, and were started on [… read more]
Overview Vasopressors and inotropes are cornerstones in the management of shock syndromes. Understanding vasopressors’ receptor activity and resultant pharmacological response enables clinicians to select the ideal vasopressor(s) for a patient suffering from shock. The following table outlines common vasopressors/inotropes and their general receptor activity profiles.1,2 Drug Dose α1 ß1 ß2 DA V1 V2 cAMP Norepinephrine [… read more]
N-acetylcysteine (NAC) and sodium bicarbonate are commonly provided to patients undergoing angiographic procedures with intravenous contrast. Small randomized trials had suggested NAC or bicarbonate or both could prevent kidney injury from so-called contrast nephropathy. That practice has no benefit, based on results of a large randomized trial showing neither NAC nor bicarb improved outcomes after [… read more]
Jon-Emile S. Kenny MD [@heart_lung] “Upward, not northward.” -E. A. Abbott A pressure chamber within a pressure chamber; the heart within the thorax. These are two pumps beating in-and-out of time, varying in physiology and pathophysiology between patients and within any one patient during the arc of an illness. As such, when we inspect the [… read more]
Jon-Emile S. Kenny MD [@heart_lung] with illustrations by Carla M Canepa MD “… And you may ask yourself … well, how did I get here? … And you may tell yourself … my God! What have I done?” -David Byrne A 92 year old woman is transferred to the coronary care unit for treatment of pulmonary edema. She [… read more]
In pulmonary embolism (PE), right ventricular (RV) strain on transthoracic echocardiography increases the likelihood of shock and mortality. One study showed among patients with PE and normal blood pressure, 10% of those with RV strain on echocardiogram developed shock, and 5% died in hospital. Those without RV strain maintained their blood pressure and survived (but important [… read more]
Jon-Emile S. Kenny MD [@heart_lung] In the last few weeks I have been contacted by curious clinical physiologists craving my conceptions of ‘venous excess’ [1]. These words will address this model, concisely and – I pray – clearly. The Myth of Venous Return The roots of venous excess took hold within the fertile soil of [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Three years ago I wanted to share my physiology website heart-lung.org; I needed a topic to stoke some interest, so I sent a brief essay to Matt here at pulmccm.org. In it, I briefly described inspiratory IVC collapse and its relationship to volume status and volume responsiveness. With this, the [… read more]
“Stop chest compressions for a minute while I intubate this patient!” That refrain must have been heard tens of thousands of times during CPR after cardiac arrest before 2010, when the American Heart Association’s (AHA) Advanced Cardiac Life Support (ACLS) guidelines advised resuscitation teams not to interrupt chest compressions to place advanced airways, unless a patient [… read more]
Will “therapeutic” hypothermia someday need to be renamed? After a rush of optimism surrounding small trials showing large benefits from hypothermia to 33° after out-of-hospital cardiac arrest, hospitals and intensivists flocked to provide hypothermia to all victims of cardiac arrest (in- or out-of-hospital). When the much more powerful TTM trial showed no benefit of deep cooling [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Briefly, part 1 of this reflection on the mean systemic filling pressure [Pmsf] considered an analogy for volume status as the vastness of an ocean beyond the hull of a leaking ship; I argue that looking only inside the hull of the ship cannot tell you the volume of the [… read more]
Jon-Emile S. Kenny MD [@heart_lung] It’s 4 in the morning; I am somewhere between Riga and Stockholm. The moon is full and bright and rippling across the black, Baltic Sea. This warm, June darkness is cut like onyx by deep vibrations of a cruise ship and its collections of giggling Swedes; they karaoke ‘Spaceman’ by [… read more]
Therapeutic hypothermia after cardiac arrest was almost immediately accepted as standard care in 2002 when two smallish, unblinded randomized trials (n=77 and n=273) showed a significant benefit from hypothermia after out-of-hospital ventricular fibrillation cardiac arrest. Hospitals and their cardiac care units quickly adopted resource-intensive protocols to manage patients’ special needs while being cooled to an icy 33° [… read more]
Cooling kids to 33ºC after resuscitation from in-hospital cardiac arrest brought no benefits compared to fever prevention (maintenance at 36.8°C), in the large THAPCA randomized trial. After one year, survival was 39% with hypothermia and 36% with management of body temperature in the normal range. There were no differences in neurologic outcomes or any other [… read more]
Jon-Emile S. Kenny MD [@heart_lung] Hemodynamic assessment, by any means, demands a shrewd familiarity with mechanical heart-lung interaction. The two ventricles communicate in series and in parallel; each ventricle’s pressure-volume characteristics and loading conditions pulsate between systole and diastole. And around the heart and pericardium lies the respiratory pump – the lungs within the thorax [… read more]
By Jon-Emile S. Kenny [@heart_lung] When interpreting hemodynamic studies of drugs which – potentially – alter the resistance of the pulmonary vascular tree, we often turn to the calculated pulmonary vascular resistance [cPVR] as our guide. For instance, a vasopressor determined to increase the cPVR is wholly avoided in a patient with pulmonary arterial hypertension. We [… read more]
What’s the shelf life of human blood? Like the milk in your fridge, stored donated human blood has an expiration date: currently it’s 42 days, set by the FDA. But is fresher blood actually better? As with ordering wine by the glass, should patients about to be transfused blood ask for “whatever was opened most recently”? There’s [… read more]
By Jon-Emile S. Kenny [@heart_lung] “Major Major had been born too late and too mediocre. Some men are born mediocre, some men achieve mediocrity, and some men have mediocrity thrust upon them. With Major Major it had been all three …” -Joseph Heller In my younger days, parked on a bench overlooking Stanley Park, I sought [… read more]
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