Critical Care Update: Cardiac, Neuro, Surgical and Medical ICU
By Christian S. Guay, MD, from the IARS, AUA and SOCCA 2019 Annual Meetings*
Four leading experts in critical care reviewed advances in their sub-fields over the past year on Monday, May 20 during the session, What’s New in Critical Care: Cardiac, Neuro, Surgical and Medical Intensive Care. Prominent topics included advances in ultrasound and microvascular assessments, shifting therapeutic windows in stroke care, infectious proteinopathy of the lung, optimizing driving pressures during mechanical ventilation and medical treatment of sepsis.
This exciting panel brought new advances in all aspects of the world of ICU to attendees, from cardiac and neuro to surgical and medical critical care.
Michael Wall, MD, FCCM, University of Minnesota Medical School, started the panel with a discussion of cardiac critical care. A recent meta-analysis revealed that epinephrine is associated with a threefold increase in mortality in the setting of cardiogenic shock but needs to be validated by a prospective pragmatic clinical trial. The microvascular literature also made an appearance, with a study of thenar and forearm NIRS-derived variables shown to predict both ICU and hospital length of stay, as well as duration of mechanical ventilation. However, as was noted in a previous panel, we still do not have effective methods to directly improve microvascular perfusion. An easy-to-implement study was then presented, where routine high flow nasal oxygen for 24 hours in cardiac surgery patients at high risk for respiratory complications decreased hospital length of stay and ICU re-admission. Mild hypothermia has been shown to decrease the incidence of AKI after CPR. A new measure of venous congestion, portal vein pulsatility on bedside ultrasound, was found to be associated with an increased risk of AKI. These patients may be trialed with diuretics in a future clinical trial. Dr. Wall closed with a discussion on nutrition in critical care and emphasized the benefit of early postoperative nutrition in high-risk patients.
Jean Charchaflieh, MD, MPH, DrPH, Yale School of Medicine, followed Dr. Wall with an overview of advances in neurocritical care, focusing on stroke, TBI, and NMDA receptor encephalitis. There has been a recent shift in the management of acute ischemic stroke from time-based therapeutic windows to image-based windows. This is most apparent in the care of patients with a mismatch in their imaging and clinical exam, suggestive of a penumbra of salvageable neural tissues, whose therapeutic window for intravascular therapy has been extended to 24 hours by the DAWN trial. Another recent trend in stroke care has been to investigate general anesthesia versus conscious sedation for intravascular stroke therapies. Three recent large clinical trials showed no difference in outcome between the two approaches. In the world of TBI, there has been recent interest in protocolized care and subspecialty neuro-ICU units. A recent study found no difference in outcomes for patients treated in specialized neuro-ICUs, but did report improved outcomes for patients treated according to clinical protocols (e.g., for sedation, weaning mechanical ventilation). There has also been confirmation for lack of efficacy (and potential harm) of therapeutic hypothermia in patients with TBI. Dr. Charchaflieh then noted a study of closed-claims in anesthesia showing the relatively high incidence of difficult intubation leading to legal claims in the setting of cervical spine surgery, often related to cervical edema and hematomas. He finished his presentation with an overview of N-methyl-D-aspartate (NMDA) receptor encephalitis, which was reviewed in 2018. In short, most cases are due to teratomas with nervous tissues generating antibodies against NMDA receptors, which can result in essentially any manifestation of nervous system disease. Treatment involves temporary immune suppression, and most patients recover following tumor resection.
Jean-François Pittet, MD, University of Alabama at Birmingham, took a slightly different approach to his presentation, focusing on recent research clarifying the pathophysiology of pneumonia. He started by dispelling two common erroneous concepts, namely that pneumonia is a localized process and that it is an acute disease. Dr. Pittet’s research suggests that bacteria inject toxins into cells, leading to the generation of cytotoxic microtubule-derived proteins: tau and beta-amyloid. The circulation of these proteins in plasma and cerebrospinal fluid may explain some of the chronic effects seen in post-ICU syndrome. Dr. Pittet termed this phenomenon infectious proteinopathy of the lung.
Focusing on medical critical care, Ronald Pearl, MD, PhD, Stanford University School of Medicine, wrapped up the panel with a discussion of acute respiratory distress syndrome (ARDS), sepsis and post-ICU care. In discussing ARDS, Dr. Pearl emphasized the association of low-driving pressures with reduced ventilator-induced lung injury. Concurrently increasing PEEP and decreasing plateau pressure maintains the same peak pressure and decreases driving pressure. In general, driving pressures should be kept below 18 mmHg, and a target of 14 mmHg is emerging in the literature. Moving on to a discussion of sepsis, Dr. Pearl reminded attendees that norepinephrine remains the first line vasopressor for septic shock, followed by vasopressin and the recently added option of angiotensin II. Emerging evidence also supports the use of hydrocortisone (200mg/day) for all patients in septic shock and is likely to be included in future guidelines. A large trial is under way to confirm the benefit of vitamin C in sepsis. Dr. Pearl closed his presentation with a discussion of post-ICU clinics. These clinics, which have become standard in the UK, are staffed by ICU physicians. The main benefits of such clinics are the appropriate management of postintensive care syndrome and discontinuation of drugs originally started in the ICU such as amiodarone and haloperidol.
*Coverage from the Panel: What’s New in Critical Care: Cardiac, Neuro, Surgical and Medical Intensive Care, presented by Michael Wall, MD, Ronald Pearl, MD, PhD, Jean Charchaflieh, MD, MPH, DrPH, Jean-François Pittet, MD, during the IARS 2019 Annual Meeting