Critical Care

Out of rhythm: Melatonin dysregulation in critical illness

 

We do not often give thought to the factors controlling our circadian rhythm. And yet the circadian system modulates many physiologic systems, including brain arousal, cardiovascular function, sympathetic tone, appetite, metabolism and immune system function. Similar to the sinoatrial node pacing the heart, the suprachiasmatic nucleus located in the hypothalamus serves as the central pacemaker for the circadian rhythm, directing sleep, motor activity, temperature and autonomic tone. Rhythmic release of melatonin from the pineal gland helps drive this central clock in addition to other circadian biomarkers, including cortisol and core body temperature. In healthy individuals, plasma melatonin concentrations typically measure 10-fold higher at night than during the daytime. How does critical illness affect circadian rhythm, specifically melatonin secretion?

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When the PLT get LOW

A 72 y/o male with PMH type 2 diabetes, CAD, HFrEF, HTN, and HLD is admitted to the MICU for frequent neurologic monitoring after an endovascular thrombectomy for an acute ischemic stroke caused by thrombosis of the M2 branch of the left MCA. While reviewing his chart, you notice that the patient was recently admitted for 1 week about 10 days ago for dyspnea secondary to acute decompensated heart failure. You also note on his admission labs that he is newly thrombocytopenic, with a platelet count of 80,000. His last platelet count on discharge was 250,000, and he has never been thrombocytopenic before. What is causing his thrombocytopenia?

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ECMO: What is the Intensivist’s Role?

 

A 52-year-old man with a history significant for hypertension presented to the emergency department with cough, dyspnea and fever. He progressed to severe acute respiratory distress syndrome (ARDS) secondary to COVID-19 pneumonia. He developed refractory hypoxemia with P/F < 60 mm Hg despite low tidal volume ventilation, paralysis, inhaled epoprostenol and prone positioning. Is this patient a candidate for venovenous ECMO and, if so, who should guide initiation and management of ECMO? The Society of Critical Care Medicine (SCCM) and Extracorporeal Life Support Organization (ELSO) recently published a position paper on the role of the intensivist in the initiation and management of ECMO. 

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BVM - Do no harm

It’s been a busy day in the ED and you’ve had several cardiac arrests come in back to back.  EMS calls in with another one just as they’re hitting the door.  The patient is an adult, but you notice the BVM they’re using is much smaller than what you’re used to seeing.  The medic says “The day has been so bad, we didn’t have time to get back to base to restock the rig.  We only had a pediatric BVM.”  Knowing that safe ventilation includes limiting tidal volumes and pressures, you wonder what the implications of using a pediatric BVM are.

Angiotensin II and COVID-19

As we learn more about the pathophysiology of COVID-19, alternative treatments are being explored for the severe sequelae of this disease. SARS-CoV-2 enters human cells via the ACE2 receptor, located in many organs, including the heart, vascular endothelium, and alveolar epithelium causing an inflammatory cascade that can lead to ARDS, vasodilatory shock, myocarditis, acute kidney injury and capillary leak. Given the relationship between SARS-CoV-2 and the RAAS, is there a role for angiotensin II in vasodilatory shock caused by COVID-19?

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ECMO in pregnancy

 

A 36-year-old woman presented to urgent care with cough, dyspnea and hypoxemia. She was transported to the ED where she rapidly progressed to severe ARDS despite lung protective ventilation, paralysis and inhaled epoprostenol. Post-intubation, it was determined that she was pregnant with ultrasound revealing a fetus at 23 weeks, 6 days gestational age. She underwent cannulation for venovenous ECMO. What is the role of ECMO in the pregnant patient? A recently published analysis of the ELSO registry for peripartum patients supported with ECMO demonstrates a 70 percent survival rate. 

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