Neal H. Cohen

death and Other Complications of Emergency Airway Management in Critically Ill Adults : a Prospective Investigation of 297 Tracheal Intubations

Background Hospitalized patients outside of the operating room frequently require emergency airway management. This study investigates complications of emergency airway management in critically ill adults, including: (1) the incidence of difficult and failed intubation; (2) the frequency of esophageal intubation; (3) the incidence of pneumothorax and pulmonary aspiration; (4) the hemodynamic consequences of emergent intubation, including death, during and immediately following intubation; and (5) the relationship, if any, between the occurrence of complications and supervision of the intubation by an attending physician. Methods Data were collected on consecutive tracheal intubations carried out by the intensive care unit team over a 10‐month period. Non‐anesthesia residents were supervised by anesthesia residents, critical care attending physicians, or anesthesia attending physicians. Results Two hundred ninety‐seven consecutive intubations were carried out in 238 adult patients. Translaryngeal tracheal intubation was accomplished in all patients. Intubation was difficult in 8% of cases (requiring more than two attempts at laryngoscopy by a physician skilled in airway management). Esophageal intubation occurred in 25 (8%) of the attempts but all were recognized before any adverse sequelae resulted. New infiltrates suggestive of pulmonary aspiration were present on chest radiograph after 4% of intubations. Seven patients (3%) died during or within 30 min of the procedure. Five of the seven patients had systemic hypotension (systolic blood pressure less or equal to 90 mmHg), and four of the five were receiving vasopressors to support systolic blood pressure. Patients with systolic hypotension were more likely to die after intubation than were normotensive patients (P < 0.001). There was no relationship between supervision by an attending physician and the occurrence of complications. Conclusions In critically ill patients, emergency tracheal intubation is associated with a significant frequency of major complications. In this study, complications were not increased when intubations were accomplished without the supervision of an attending physician as long as the intubation was carried out or supervised by an individual skilled in airway management. Mortality associated with emergent tracheal intubation is highest in patients who are hemodynamically unstable and receiving vasopressor therapy before intubation.

Transesophageal echocardiography predicts mortality in critically III patients with unexplained hypotension

OBJECTIVES This study sought to determine the prognostic yield and utility of transesophageal echocardiography in critically ill patients with unexplained hypotension. BACKGROUND Transesophageal echocardiography is increasingly utilized in the intensive care setting and is particularly suited for the evaluation of hypotension; however, the prognostic yield of transesophageal echocardiography in these patients is unknown. METHODS We prospectively studied 61 adult patients in the intensive care unit with sustained (> 60 min) unexplained hypotension. Both transthoracic and transesophageal echocardiography were performed, and results were immediately disclosed to the primary physician, who reported any resulting changes in management. Patients were classified on the basis of transesophageal echocardiographic findings into one of three prognostic groups: 1) nonventricular (valvular, pericardial) cardiac limitation to cardiac output; 2) ventricular failure; and 3) noncardiac systemic disease (hypovolemia or low systemic vascular resistance, or both). Primary end points were death or discharge from the intensive care unit. RESULTS A transesophageal echocardiographic diagnosis of nonventricular limitation to cardiac output was associated with improved survival to discharge from the intensive care unit (81%) versus a diagnosis of ventricular disease (41%) or hypovolemia/low systemic vascular resistance (44%, p = 0.03). Twenty-nine (64%) of 45 transthoracic echocardiographic studies were inadequate compared with 2 (3%) of 61 transesophageal echocardiographic studies (p < 0.001). Transesophageal echocardiography contributed new clinically significant diagnoses (not seen with transthoracic echocardiography) in 17 patients (28%), leading to operation in 12 (20%). CONCLUSIONS Transesophageal echocardiography makes a clinically important contribution to the diagnosis and management of unexplained hypotension and predicts prognosis in the critical care setting.

Open innovation networks between academia and industry: an imperative for breakthrough therapies.

Open innovation networks between academia and industry: an imperative for breakthrough therapies

A comparison of three methods of hemoglobin monitoring in patients undergoing spine surgery.

BACKGROUND:Hemoglobin values (Hb) can facilitate decisions regarding perioperative transfusion management. Currently, Hb can be determined invasively by analyzing blood via laboratory Co–Oximetry (tHb) or by point-of-care HemoCue (HCue). Recently, a new noninvasive, continuous spectrophotometric sensor (Masimo SpHb) was introduced into clinical practice. We compared the accuracy of the SpHb and HCue with tHb. METHODS:Twenty patients, ages 40 to 80 years, were studied. They received general anesthesia and underwent spine surgery in the prone position. All blood samples were obtained from a radial artery catheter. SpHb, tHb, and HCue were determined immediately after induction of anesthesia, but before the start of surgery and approximately every hour thereafter. Primary outcomes were defined on the basis of the following differences between measures: SpHb − tHb or HCue − tHb. All patients had 3 to 5 observations taken on each measure. Differences and absolute differences were analyzed by several techniques to assess accuracy. We also investigated the relationship between observed differences and the following variables: tHb level, duration of surgery, age, weight, and perfusion index. RESULTS:Data consisted of 78 measurements of SpHb, tHb, and HCue made on the 20 patients. Absolute differences between SpHb and tHb were <1.5 g/dL for 61% of observations, between 1.6 to 2.0 g/dL for 16% and >2.0 g/dL for 22% of the observations. Observed differences displayed significant decreases with time and higher perfusion index values. No systematic relationships were observed with age or weight. Except for 1 value, all of the HCue values were <1.0 g/dL of tHb. CONCLUSIONS:Although HCue was consistently accurate, our data confirm that SpHb often correlated well with tHb values. Yet our study indicates that SpHb may not be as accurate as clinically necessary in some patients. Improved refinement of continuous, noninvasive technology, such as SpHb, could address important clinical requirements.

Guidelines for critical care medicine training and continuing medical education.

ObjectiveCritical care medicine trainees and faculty must acquire and maintain the skills necessary to provide state-of-the art clinical care to critically ill patients, to improve patient outcomes, optimize intensive care unit utilization, and continue to advance the theory and practice of critical care medicine. This should be accomplished in an environment dedicated to compassionate and ethical care. ParticipantsA multidisciplinary panel of professionals with expertise in critical care education and the practice of critical care medicine under the direction of the American College of Critical Care Medicine. ScopePhysician education in critical care medicine in the United States should encompass all disciplines that provide care in the intensive care unit and all levels of training: from medical students through all levels of postgraduate training and continuing medical education for all providers of clinical critical care. The scope of this guideline includes physician education in the United States from residency through ongoing practice after subspecialization. Data Sources and SynthesisRelevant literature was accessed via a systematic Medline search as well as by requesting references from all panel members. Subsequently, the bibliographies of obtained literature were reviewed for additional references. In addition, a search of organization-based published material was conducted via the Internet. This included but was not limited to material published by the American College of Critical Care Medicine, Accreditation Council for Graduate Medical Education, Accreditation Council for Continuing Medical Education, and other primary and specialty organizations. Collaboratively and iteratively, the task force met, by conference call and in person, to construct the tenets and ultimately the substance of this guideline. ConclusionsGuidelines for the continuum of education in critical care medicine from residency through specialty training and ongoing throughout practice will facilitate standardization of physician education in critical care medicine.

Comparison of Transesophageal Echocardiographic and Scintigraphic Estimates of Left Ventricular End-Diastolic Volume Index and Ejection Fraction in Patients Following Coronary Artery Bypass Grafting

Transesophageal echocardiography (TEE) has become a commonly used monitor of left ventricular (LV) function and filling during cardiac surgery. Its use is based on the assumption that changes in LV short-axis ID reflect changes in LV volume. To study the ability of TEE to estimate LV volume and ejection immediately following CABG, 10 patients were studied using blood pool scintigraphy, TEE, and thermodilution cardiac output (CO). A single TEE short-axis cross-sectional image of the LV at the midpapillary muscle level was used for area analysis. Between 1 and 5 h postoperatively, simultaneous data sets (scintigraphy, TEE, and CO) were obtained three to five times in each patient. End-diastolic (EDa) and end-systolic (ESa) areas were measured by light pen. Ejection fraction area (EFa) was calculated (EFa = (EDa - ESa)/EDa). When EFa was compared with EF by scintigraphy, correlation was good (r = 0.82 SEE = 0.07). EDa was taken as an indicator of LV volume and compared with LVEDVI which was derived from EF by scintigraphy and CO. Correlation between EDa and LVEDVI was fair (r = 0.74 SEE = 3.75). The authors conclude that immediately following CABG, a single cross-sectional TEE image provides a reasonable estimate of EF but not LVEDVI.

Pancuronium reduces halothane requirement in man.

We studied the contribution of pancuronium to anesthetic requirement in man by comparing MAC for halothane alone in 18 patients, with that after intravenous administration of pancuronium, 0.1 mg/kg, in 17 patients. In each group, movement was observed in limbs isolated from the circulation by tourniquet. In patients receiving pancuronium, halothane MAC was 0.55%, whereas the control value was 0.73%. Thus pancuronium reduces halothane MAC by 25%.

Women are at greater risk than men for malpositioning of the endotracheal tube after emergent intubation

ObjectivesTo investigate the occurrence of endotracheal tube malpositioning after emergent intubation in critically ill adults and to determine the need for a routine postintubation chest radiograph to assess endotracheal tube position. DesignProspective study. SettingAll adult critical care and acute care units of a 560-bed university teaching hospital. PatientsStudy of 297 consecutive intubations (185 intubations in males and 112 intubations in females) in 238 adult patients. MethodsEmergent endotracheal intubations were performed by resident physicians with supervision from an intensive care unit (ICU) or anesthesia attending physician or an anesthesia resident. After intubation, proper positioning of the endotracheal tube was verified by the intubating physician using clinical criteria, including auscultation of bilateral breath sounds, symmetric chest expansion, and palpation of the endotracheal tube cuff in the suprasternal notch. The endotracheal tube position relative to the lower anterior incisors or alveolar ridge was recorded using the centimeter markings printed on the endotracheal tube. A chest radiograph was obtained after intubation to verify endotracheal tube position. Appropriate endotracheal tube position on chest radiograph was defined as between >2 and ≤6 cm above the carina. Measurements and Main ResultsOf the 297 intubations, 26 were excluded from analysis because a chest radiograph was not obtained or the patient was not of normal stature. For the remaining 271 intubations, 42 (15.5%) endotracheal tubes were inappropriately placed, according to the radiographic assessment. The percentage of malpositioned endotracheal tubes was significantly higher in women than in men (61.9% vs. 38.1%, respectively; chi-square: p < .001). Thirty-three (78.6%) of 42 malpositioned endotracheal tubes were placed <2 cm from the carina, with the highest occurrence (24/33) of proximal malposition occurring in women. Positioning of endotracheal tubes using the centimeter markings printed on the tube referenced to the lower incisors did not accurately identify malposition as documented by chest radiograph. ConclusionsEmergent endotracheal intubations result in a significant occurrence of malpositioned endotracheal tubes that are undetected by clinical evaluation. Malpositioning is not detected by routine clinical assessment, but only by chest radiograph. Women are at greater risk than men for endotracheal tube malpositioning after emergent intubation; in women, the endotracheal tube is more likely to be positioned too close to the carina. A chest radiograph for confirmation of endotracheal tube position after emergent intubation should remain the standard of practice. (Crit Care Med 1994; 22:1127–1131)

Changes in acetylcholine receptor number in muscle from critically ill patients receiving muscle relaxants: an investigation of the molecular mechanism of prolonged paralysis.

OBJECTIVE Previous reports have described prolonged paralysis after the administration of muscle relaxants in critically ill patients. The purpose of this study was to examine possible pathophysiologic causes for this paralysis by measuring muscle-type, nicotinic acetylcholine receptor number in necropsy muscle specimens from patients who had received muscle relaxants to facilitate mechanical ventilation before death. DESIGN Prospective laboratory study of human muscle collected at autopsy. SETTING Medical and surgical intensive care units (ICUs) at a university hospital and a research laboratory. PATIENTS Fourteen critically ill patients, with a variety of diagnoses, all of whom required mechanical ventilatory support before their deaths in the ICU and who underwent post mortem examination. Patients were arbitrarily divided into three groups, according to their total vecuronium dose and number of days mechanically ventilated before death. Three patients were in the control group (defined as dying within 72 hrs of initiation of ventilatory support and receiving a total dose of < 5 mg of vecuronium). Six patients were in the low-dose group (defined as requiring ventilatory support for > 3 days before death and receiving a total vecuronium dose of < or = 200 mg). Five patients were in the high-dose group (defined as requiring ventilatory support for > 3 days before death and receiving a total vecuronium dose of > 200 mg). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Nicotinic acetylcholine receptor numbers as measured by specific 125I-alpha-bungarotoxin binding to human rectus abdominis muscle obtained at autopsy were determined. In general, receptor number reflected the clinical requirements for the muscle relaxants of each patient. Patients who had increasing requirements for muscle relaxants before death had increases in receptor number, as compared with control values. CONCLUSIONS The increase in nicotinic acetylcholine receptor number in muscle from patients with an increasing requirement for muscle relaxants before death suggests that nicotinic acetylcholine receptor up-regulation may underlie the increased requirements for muscle relaxants seen in some patients. Furthermore, these findings suggest that muscle relaxant-induced, denervation-like changes may at least be partially responsible for prolonged muscle paralysis after the long-term administration of muscle relaxants. This study may provide the first information into the molecular mechanisms underlying prolonged paralysis.

Washin and washout of isoflurane administered via bubble oxygenators during hypothermic cardiopulmonary bypass.

Washin and washout of a volatile anesthetic given through the oxygenator during hypothermic (23.4 +/- 2.1 degrees C) cardiopulmonary bypass were studied in nine patients. The authors administered isoflurane and measured its partial pressure in arterial (Pa) and venous (Pv) blood and the gas exhausted from the oxygenator (PE) at 1, 2, 4, 8, 16, 32, and 48 min during washin. These measurements were repeated during washout, which coincided with rewarming. During washin, PE, Pa, and Pv progressively rose toward inlet gas partial pressure (PI). Equilibration of Pa with PI was 41% after 16 min, 51% after 32 min, and 57% after 48 min of washin. During washout, Pa declined to 24% of its peak after 16 min and to 13% after 32 min. Washin and washout were considerably slower in mixed venous blood. Washin of isoflurane appeared to occur more slowly during cardiopulmonary bypass than during administration via the lungs in normothermic patients, presumably because hypothermia increases tissue capacity, compensating for the effect of hemodilution that otherwise would decrease the blood/gas partition coefficient. During rewarming, washout appeared to occur as rapidly as from the lungs of normothermic patients. This may have resulted from the declining blood/gas partition coefficient (due to rewarming) and relatively limited tissue stores of isoflurane. The relationship between exhaust and arterial partial pressures was reasonably consistent; for clinical purposes, measurement of PE can be used to estimate Pa.