This paper reviews the molecular basis of circadian rhythms and the pathophysiologic consequences of alterations in these rhythms, and explores the concept of daylight as therapy to restore disrupted circadian rhythms and improve clinical outcomes.

The rotation of the earth and associated alternating cycles of light and dark–the basis of our circadian rhythms–are fundamental to human biology and culture. However, it was not until 1971 that researchers first began to describe the molecular mechanisms for the circadian system. During the last few years, groundbreaking research has revealed a multitude of circadian genes affecting a variety of clinical diseases, including diabetes, obesity, sepsis, cardiac ischemia, and sudden cardiac death. Anesthesiologists, in the operating room and intensive care units, manage these diseases on a daily basis as they significantly impact patient outcomes. Intriguingly, sedatives, anesthetics, and the ICU environment have all been shown to disrupt the circadian system in patients. In the current review we will discuss how newly acquired knowledge of circadian rhythms could lead to changes in clinical practice and new therapeutic concepts.

Background Thoracic surgery patients are at high-risk for adverse pulmonary outcomes. Heated humidified high-flow nasal cannula oxygen (HHFNC O2) may decrease such events. We hypothesized that patients randomized to prophylactic HHFNC O2 would develop fewer pulmonary complications compared to conventional O2 therapy. Methods and Patients Fifty-one patients were randomized to HHFNC O2 vs. conventional O2. The primary outcome was a composite of postoperative pulmonary complications. Secondary outcomes included oxygenation and length of stay. Continuous variables were compared with t-test or Mann-Whitney-U test, categorical variables with Fisher’s Exact test. Results There were no differences in postoperative pulmonary complications based on intention to treat [two in HHFNC O2 (n=25), two in control (n=26), p=0.680], and after exclusion of patients who discontinued HHFNC O2 early [one in HHFNC O2 (n=18), two in control (n=26), p=0.638]. Discomfort from HHFNC O2 occurred in 11/25 (44%); 7/25 (28%) discontinued treatment. Conclusions Pulmonary complications were rare after thoracic surgery. Although HHFNC O2 did not convey significant benefits, these results need to be interpreted with caution, as our study was likely underpowered to detect a reduction in pulmonary complications. High rates of patient-reported discomfort with HHFNC O2 need to be considered in clinical practice and future trials.

Objectives: No consensus exists on a standardized critical care content outline for medical student education. The aim of this research is to develop a national undergraduate medical education critical care content outline. Design: The authors used a Delphi process to reach expert consensus on a content outline that identified the core critical care knowledge topics and procedural skills that medical students should learn prior to entering residency. Over three iterative rounds, the expert panel reached consensus on a critical care content outline. Setting: An electronic survey of critical care medical educators, residency program directors, and residents in the United States. Subjects: The expert panel included three groups as follows: 1) undergraduate medical education critical care educators, 2) residency program directors representing all core specialties, and 3) residents representing their core specialties. Interventions: None. Measurements and Main Results: The expert panel included 28 members. Experts represented the following medical specialties: anesthesiology, emergency medicine, internal medicine, obstetrics and gynecology, pediatrics, and surgery. Seventeen experts had subspecialty training in critical care. The expert panel identified 19 highly recommended critical care knowledge topics and procedural skills. These topics and procedural skills were grouped into five broad categories as follows: 1) neurologic, 2) respiratory, 3) cardiovascular, 4) renal and electrolytes, and 5) supplemental ICU topics. Bag-mask ventilation was the only procedural skill identified as highly recommended. Conclusions: This study provides a national consensus undergraduate medical education critical care content outline. By including experts from multiple specialties, this content outline is meaningful for medical student education, independent of medical specialty. The content outline represents a first step in the development of a national undergraduate medical education critical care curriculum.

Postoperative pulmonary complications following cardiac and thoracic surgery are common and associated with significant morbidity and mortality. Noninvasive ventilation has emerged as a successful and well-validated strategy to treat various acute medical conditions. More recently, noninvasive ventilation has been studied in selective surgical patient populations with the goal of preventing postoperative complications and treating acute respiratory failure. In this clinical review, we will briefly examine the incidence of pulmonary complications following cardiothoracic surgery and the physiology and mechanics of acute respiratory failure and noninvasive ventilation. We then present a systematic review of the indications, patient selection, and current literature investigating the specific use of noninvasive ventilation in this population.