Hydroxocobalamin Versus Methylene Blue for Vasoplegic Syndrome in Cardiothoracic Surgery: A Retrospective Cohort.

OBJECTIVE: To compare methylene blue with hydroxocobalamin as a rescue therapy for vasoplegic syndrome. DESIGN: Retrospective cohort. SETTING: Academic medical center. PARTICIPANTS: Patients undergoing cardiothoracic surgery treated for vasoplegic syndrome. INTERVENTIONS: Thirty-five patients were treated with methylene blue (n = 16) or hydroxocobalamin (n = 19). MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure, systemic vascular resistance, and vasopressor exposures were recorded before and after medication administration. Change in time-averaged norepinephrine equivalents in the hour after administration was the primary outcome. The average norepinephrine equivalent observed at baseline in this cohort was 0.347 µg/kg/min. Methylene blue patients had greater Acute Physiological Assessment and Chronic Health Evaluation II scores (29.8 v 22.2; p = 0.01) and trended toward greater European System for Cardiac Operative Risk Evaluation II values (26.8% v 15.1%; p = 0.07). Methylene blue and hydroxocobalamin were associated with increased mean arterial pressure and systemic vascular resistance 1 hour after administration (10.6 mmHg and 192 dyn*sec/cm5; p = 0.01 and p = 0.01, respectively; 11.8 mmHg and 254 dyn*sec/cm5; p = 0.002 and p = 0.015, respectively). Hemodynamic changes were not different between the rescue therapy groups (p = 0.79 and p = 0.53, respectively). No significant differences were observed within the 1-hour change in time-averaged norepinephrine equivalents for either agent or when methylene blue and hydroxocobalamin were compared (0.012 ± 0.218 µg/kg/min v -0.037 ± 0.027 µg/kg/min; p = 0.46, respectively). When compared with baseline time-averaged norepinephrine equivalent (0.326 ± 0.106 µg/kg/min), only hydroxocobalamin was associated with decreased vasopressor requirements at the 1-hour (0.255 ± 0.129 µg/kg/min; p = 0.03) and 4-hour time points (0.247 ± 0.180 µg/kg/min; p = 0.04) post-administration. CONCLUSION: Methylene blue and hydroxocobalamin increased mean arterial pressures and systemic vascular resistance without significantly decreasing time-averaged norepinephrine exposure in the hour after administration.

Quick reference tidal volume cards reduce the incidence of large tidal volumes during surgery.

Ventilation with large tidal volumes (V T), greater than 10 ml/kg of predicted body weight (PBW), is associated with worse outcomes in critically ill and surgical patients. We hypothesized that the availability of quick reference cards with proposed V T ranges specific to gender and different heights would reduce the intraoperative use of large V T during prolonged abdominal surgery. We compared retrospectively the incidence of median V T used during prolonged (≥4-h-long) abdominal surgery before ("before") and after ("after") the quick reference V T cards were made available in all anesthesia machines in operating rooms of a single academic US medical center. We evaluated the effect of the intervention on the primary outcome while adjusting for previously identified risk factors of large V T use: female gender, obesity (body mass index, BMI > 30), and short height (< 165 cm). The frequency of V T > 10 ml/kg PBW was 15.1% in the before group and 4.3% in the after group (p < 0.001). The frequency of large V T used during abdominal surgery was significantly decreased after the intervention even after adjusting for female gender, obesity or short height [adjOR 0.11 (95% CI 0.04-0.30)]. Our quick reference V T cards significantly reduced the frequency of large V T use during abdominal surgery.

Heated humidified high-flow nasal cannula oxygen after thoracic surgery - A randomized prospective clinical pilot trial.

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.

Troponin elevations in patients with chronic cardiovascular disease: An analysis of current evidence and significance.

Serum troponin elevation above the 99th percentile of the upper reference limit in healthy subjects (<0.01 ng/ml measured using currently available high-sensitivity cardiac troponin laboratory assays) is required to establish the diagnosis the diagnosis of myocardial necrosis in acute cardiovascular syndromes, as well as guide prognosis and therapy. In the perioperative period, for patients with cardiac disease undergoing noncardiac surgery, it is a particularly critical biomarker universally used to assess the myocardial damage. The value of troponin testing and elevation (as well as its significance) in patients with chronic cardiac valvular, vascular, and renal disease is relatively less well understood. This evidence-based review seeks to examine the currently available data assessing the significance of troponin elevation in certain chronic valvular and other disease states.

Insertion and Management of Temporary Pacemakers.

Temporary pacemakers are used in a variety of critical care settings. These life-saving devices are reviewed in 2 major categories in this review: first, the insertion and management of epicardial pacemakers after and during cardiac surgery; and second, the insertion of transvenous temporary pacemakers for the emergent treatment of bradyarrhythmias. Temporary epicardial pacemakers are used routinely in patients recovering from cardiac surgery. Borrowing from advances in cardiac resynchronization therapy there are many theoretical and untested benefits to pacing the postoperative cardiac surgery patient. Temporary transvenous pacing is traditionally an emergency procedure to stabilize patients suffering from hemodynamically unstable bradyarrhythmia. We review the traditional and expanding use of transvenous pacemakers inside and outside the operating room.

Promotion of progressive mobility activities with ventricular assist and extracorporeal membrane oxygenation devices in a cardiothoracic intensive care unit.

BACKGROUND: Progressive mobility (PM) is a clinical intervention that influences complications experienced throughout critical illness. Early PM is a relevant topic in critical care practice literature and was principle to introducing a PM care guideline in an acute cardiothoracic/cardiovascular intensive care unit. PURPOSE: A noted challenge in the cardiothoracic/cardiovascular intensive care unit is caring for acute cardiac and pulmonary failure. Often, these patients require prolonged mechanical circulatory support via extracorporeal mechanical oxygenation or a ventricular assist device. This article describes safe and effective progressive mobilization for patients experiencing MCS in a case study format. This article also highlights how a multidisciplinary clinical team supports mobility practice in specific critical care roles. CONCLUSIONS: Post-intensive care syndrome is composed of various health implications that occur following critical illness. Recent data suggest improved care outcomes when critically ill patients are awake and participate in active physical rehabilitation as early as clinically possible. The case studies presented indicate that mobility, to the point of ambulation, is a feasible clinical expectation when patients present with substantial acute respiratory and cardiac failure and are managed with MCS. CLINICAL IMPLICATIONS: Development of a PM guideline uses a critical appraisal of practice evidence, highlights multidisciplinary collaboration, and increases progression to ambulation. Mobility for complex patients is attainable, as demonstrated in the postguideline outcomes. The PM guideline provides structure to primary caregivers and promotes safe practices. The PM guideline facilitates an advanced level of care, promotes safe practices, champions holistic recovery, and encourages active patient involvement, goals satisfying to both patients and staff.

Update on perioperative right heart assessment using transesophageal echocardiography.

PURPOSE OF THE REVIEW: This review aims to summarize recent findings relevant for perioperative 2- and 3-dimensional imaging of the right heart with transesophageal echocardiography. Special attention is given to developments that are likely to affect future approaches for prevention and therapy of perioperative right heart failure. RECENT FINDINGS: Three-dimensional transesophageal echocardiography techniques are becoming more common for the evaluation of anatomy, volumes, and functional indices. SUMMARY: Right heart failure continues to contribute to morbidity and mortality in the context of cardiothoracic surgery. The advent and widespread clinical use of innovative tools permitting more accurate echocardiographic assessment of the right heart will open the door to renewed interest in novel therapeutic strategies.

Transesophageal echocardiography in noncardiac thoracic surgery.

In high-risk surgeries with medically complicated patients, transesophageal echocardiography (TEE) adds an additional level of monitoring with which few can disagree. This article presents multiple applications of TEE that can assist both the anesthesiologist and the surgeon through major noncardiac thoracic surgery. It highlights how TEE can be used as an adjuvant to lung resection surgery; TEE as a monitor during lung transplantation; TEE to assess patients for extracorporeal membrane oxygenation; TEE for thoracic aortic surgery; and TEE in the assessment of patients with acute pulmonary hypertension undergoing noncardiac thoracic surgery.

Con: early extubation in the operating room following cardiac surgery.

Ultra-fast-track anesthesia for cardiac surgery introduces risks to the patient that may be mitigated by transferring the patient to the intensive care unit with a secure airway. These risks include poorly controlled pain leading to catecholamine surges that result in arrhythmias, strain on fresh suture lines, and potentially myocardial ischemia. On the converse side, the patients frequently require titration of potent narcotic pain medicine that can lead to hypoxemia and hypercarbia in the immediate postoperative stage causing myocardial dysfunction. Finally, the economic benefit of ultra-fast-track anesthesia is questionable and until there is a complete cost analysis that includes operating room time, cost of ultra-fast-track medications, and compares the cost of reintubation and delayed surgical operation, it is difficult to weigh in on the cost benefit advocated in the literature.

Sleep and well-being of ICU housestaff.

BACKGROUND: Our understanding of the effect of the Accreditation Council for Graduate Medical Education (ACGME)-mandated work-hour limitation on physicians' quality of life, sleepiness, and sleep-work habits is evolving. In this study, we sought to determine the effect of work-hour reduction on quality of life in residents and fellows (ICU housestaff) when subject to the ACGME-compliant schedule of one institution. To determine the effect of work-hour reduction on subjective and objective measures of sleepiness in ICU housestaff at a center. METHODS: A single-center study of 34 residents and 10 fellows who were studied before and after the ACGME-mandated work-hour limitation went into effect in July 2003. RESULTS: In a single center, after the work-hour reduction, residents reported statistically significant but minor improvements in sleep time, subjective sleepiness, and some aspects of quality of life (p < 0.05). Both before and after work-hour limitations, subjective sleepiness and quality-of-life indexes deteriorated during the course of the ICU rotation. Following work-hour reductions, subjective sleepiness improved (p < 0.05), but objective sleepiness was unchanged (p = 0.6). Moreover, after the implementation of work-hour reductions, 59%, 43%, and 25% of the ICU team had mean sleep latency < 10, 7, and 5 min, respectively, with 14% of the team manifesting sleep-onset rapid eye movement periods (signifying severe sleepiness) before beginning their extended work-hour period. CONCLUSIONS: In ICU housestaff, at a single center, small benefits to quality of life and subjective sleepiness were realized by an ACGME-compliant work-hour schedule. Significant levels of objective sleepiness, however, remained. Further measures may need to be undertaken to address the persistence of sleepiness in ICU housestaff. These findings may not be generalized outside of the scheduling system studied.

Activation of the neuroprotective ERK signaling pathway by fructose-1,6-bisphosphate during hypoxia involves intracellular Ca2+ and phospholipase C.

The mechanism of the neuroprotective action of the glycolytic pathway intermediate fructose-1,6-bisphosphate (FBP) may involve activation of a phospholipase-C (PLC) dependent MAP kinase signaling pathway. In this study, we determined whether FBP's capacity to decrease delayed cell death in hippocampal slice cultures is dependent on PLC signaling or activation of the intracellular Ca(2+)-MEK/ERK neuroprotective signaling cascade. FBP (3.5 mM) reduced delayed death from oxygen/glucose deprivation in CA1, CA3 and dentate neurons in slice cultures. The phospholipase-C inhibitor U73122 and the MEK1/2 inhibitor U0126 prevented this protection. In hippocampal and cortical neurons, FBP increased phospho-ERK1/2 (p42/44) immunostaining during hypoxic, but not normoxic conditions. Increased phospho-ERK immunostaining was dependent on PLC and also on MEK 1/2, an upstream regulator of ERK. Further, we found that FBP enhancement of phospho-ERK immunostaining depended on [Ca(2+)](i): PLC inhibition and the IP(3) receptor blocker xestospongin C prevented FBP from increasing [Ca(2+)](i) and increasing phospho-ERK levels. However, while FBP-induced increases in [Ca(2+)](i) were blocked by xestospongin and a PLC inhibitor, [Ca(2+)](i) increases induced by the neuroprotective growth factor BDNF were not prevented. We conclude that during hypoxia FBP initiates a series of neuroprotective signals which include PLC activation, small increases in [Ca(2+)](i), and increased activity of the MEK/ERK signaling pathway.

Isoflurane prevents delayed cell death in an organotypic slice culture model of cerebral ischemia.

BACKGROUND: General anesthetics reduce neuronal death caused by focal cerebral ischemia in rodents and by in vitro ischemia in cultured neurons and brain slices. However, in intact animals, the protective effect may enhance neuronal survival for only several days after an ischemic injury, possibly because anesthetics prevent acute but not delayed cell death. To further understand the mechanisms and limitations of volatile anesthetic neuroprotection, the authors developed a rat hippocampal slice culture model of cerebral ischemia that permits assessment of death and survival of neurons for at least 2 weeks after simulated ischemia. METHODS: Survival of CA1, CA3, and dentate gyrus neurons in cultured hippocampal slices (organotypic slice culture) was examined 2-14 days after 45 min of combined oxygen-glucose deprivation at 37 degrees C (OGD). Delayed cell death was serially measured in each slice by quantifying the binding of propidium iodide to DNA with fluorescence microscopy. RESULTS: Neuronal death was greatest in the CA1 region, with maximal death occurring 3-5 days after OGD. In CA1, cell death was 80 +/- 18% (mean +/- SD) 3 days after OGD and was 80-100% after 1 week. Death of 70 +/- 16% of CA3 neurons and 48 +/- 28% of dentate gyrus neurons occurred by the third day after OGD. Both isoflurane (1%) and the N-methyl-D-aspartate antagonist MK-801 (10 microm) reduced cell death to levels similar to controls (no OGD) for 14 days after the injury. Isoflurane also reduced cell death in CA1 and CA3 caused by application of 100 but not 500 microm glutamate. Cellular viability (calcein fluorescence) and morphology were preserved in isoflurane-protected neurons. CONCLUSIONS: In an in vitro model of simulated ischemia, 1% isoflurane is of similar potency to 10 microm MK-801 in preventing delayed cell death. Modulation of glutamate excitotoxicity may contribute to the protective mechanism.