Jinesh P. Mehta

Generation of Oxidants by Hypoxic Human Pulmonary and Coronary Smooth-Muscle Cells

BACKGROUND Pulmonary vasoconstriction in response to hypoxia is unusual inasmuch as local exposure of nonpulmonary vasculature to hypoxia results in vasodilation. It has been suggested that pulmonary artery smooth-muscle cells may relax in response to intracellular generation of reactive oxygen species (ROS) and that the production of ROS decreases under hypoxia. However, other workers report increased ROS production in human pulmonary artery smooth-muscle cells (HPASMC) during hypoxia. METHODS Using dihydrodichlorofluorescein diacetate, dihydroethidium, and Amplex Red (Molecular Probes; Eugene, OR), we estimated ROS generation by confluent primary cultures of HPASMC and human coronary artery smooth-muscle cells (HCASMC) under normoxia (20%) and acute hypoxia (5%). RESULTS All three assay systems showed that HPASMC production of ROS is decreased under hypoxia and to a greater extent than the decrease in ROS production by HCASMC. A substantially greater percentage of normoxic ROS production by HPASMC is mitochondrial (> 60%) compared to HCASMC (< 30%). CONCLUSIONS These results support the conclusion that ROS generation decreases, rather than increases, in HPASMC during hypoxia. However, as ROS production also decreases in HCASMC during hypoxia, the reason for the opposite change in vascular tone is not yet apparent.

Current Trends in Critical Care Nutrition

Nutrition in the intensive care setting is a vital part of patient care, and may even be referred to as “nutritional therapy”. Current nutritional practices have progressed a lot over the past few years, and draw from a large body of accumulating evidence. Yet, as with other trends in critical care, there are a lot of variations in the way nutrition is approached between institutions, as well as between individual physicians. This review attempts to look at some of these differences and provide recommendations based upon the available literature.

Case of Missing Plastic: Foreign Body Bronchiectasis

Bronchiectasis is a well-known entity where the airways abnormally dilate losing their natural function. Most common causes of non-cytic fibrosis bronchiectasis in the middle age group include secondary immunodeficiency, aspiration, and allergic bronchopulmonary aspergillosis (ABPA). Obstructive foreign body is an uncommon cause of bronchiectasis and is often a missed diagnosis in a localized disease. Foreign bodies can be missed making the diagnosis and treatment more challenging and hence foreign body bronchiectasis should be considered in patients presenting with focal disease. Here we describe a patient with a retained foreign body that was discovered post lobectomy during gross pathological examination of the specimen with no significant aspiration history, non-diagnostic imaging of the chest and negative bronchoscopy.

959: INVESTIGATING THE INFLUENCE OF CAFFEINE INTAKE AND THE INCIDENCE OF ICU DELIRIUM

Critical Care Medicine • Volume 46 • Number 1 (Supplement) www.ccmjournal.org Learning Objectives: ICU delirium is associated with prolonged intubation, increased length of stay, and higher mortality. Among the many factors which can influence ICU delirium we investigate caffeine. Caffeine is one of the most frequently used substances in modern society and is often overlooked as potential source of significant withdrawal symptoms when abruptly discontinued upon ICU admission. The relationship of caffeine cessation and ICU delirium rates has not been widely studied. The aim of this study was to examine the relationship between the two. Methods: A retrospectively evaluated cohort of 54 patients admitted to Cleveland Clinic Florida Medical ICU were assessed by recording CAM-ICU status (a validated and commonly used score for monitoring the ICU delirium) and the amount of caffeine they consumed daily prior to admission. Collected variables also included age, sex, primary ICU diagnosis, past medical history, ventilator days, ICU length of stay, as well as use of sedatives or pain medications. Statistical tests used in our analysis included one-way ANOVA. Results: 54 patients were enrolled in the study. Mean caffeine intake for the twenty CAM-ICU positive patients was 364.60mg per day and 187.34mg per day in the thirty-two CAMICU negative patients. 35 % of the CAM-ICU positive patients were male and 65% were female. Average age in the CAM-ICU positive group was 59 years. In the CAM-ICU negative group, 63% were male and 36% were female. Average age was in the CAM-ICU negative group was 63 years. ANOVA identified CAM-ICU positive patients to have a significantly higher daily caffeine intake. Conclusions: ICU delirium is a common and well recognized complication of critical illness. Its development can increase patient morbidity and mortality. While numerous factors likely contribute to the development of ICU delirium our data identifies that those with higher chronic daily caffeine use screen positive for delirium during their ICU stay using the CAM-ICU score. Caffeine’s withdrawal symptoms are well documented and its abrupt cessation may contribute to the development of delirium. While it is unknown whether supplementing caffeine has an impact on the incidence of ICU delirium our results do identify the need for ongoing study of this relationship. We speculate that there may be benefit in the prospective investigation of caffeine supplementation in ICU populations with elevated chronic caffeine intake to reduce withdrawal and determine if there is a reduction in rates of ICU delirium.