Effects of PaCO2 derangements on clinical outcomes after cerebral injury: A systematic review.

OBJECTIVE: Partial pressure of arterial carbon dioxide (PaCO2) is a major regulator of cerebral blood flow (CBF). Derangements in PaCO2 have been thought to worsen clinical outcomes after many forms of cerebral injury by altering CBF. Our aim was to systematically analyze the biomedical literature to determine the effects of PaCO2 derangements on clinical outcomes after cerebral injury. METHODS: We performed a search of Cochrane Library, PUBMED, CINHAL, conference proceedings, and other sources using a comprehensive strategy. Study inclusion criteria were (1) human subjects; (2) cerebral injury; (3) mechanical ventilation post-injury; (4) measurement of PaCO2; and (5) comparison of a clinical outcome measure (e.g. mortality) between different PaCO2 exposures. We performed a qualitative analysis to collate and summarize effects of PaCO2 derangements according to the recommended methodology from the Cochrane Handbook. RESULTS: Seventeen studies involving different etiologies of cerebral injury (six traumatic brain injury, six post-cardiac arrest syndrome, two cerebral vascular accident, three neonatal ischemic encephalopathy) met all inclusion and no exclusion criteria. Three randomized control trials were identified and only one was considered a high quality study as per the Cochrane criteria for assessing risk of bias. In 13/17 (76%) studies examining hypocapnia, and 7/10 (70%) studies examining hypercapnia, the exposed group (hypercapnia or hypocapnia) was associated with poor clinical outcome. CONCLUSION: The majority of studies in this report found exposure to hypocapnia and hypercapnia after cerebral injury to be associated with poor clinical outcome. However, the optimal PaCO2 range associated with good clinical outcome remains unclear.

Randomized controlled trial of inhaled nitric oxide for the treatment of microcirculatory dysfunction in patients with sepsis*.

OBJECTIVES: Sepsis treatment guidelines recommend macrocirculatory hemodynamic optimization; however, microcirculatory dysfunction is integral to sepsis pathogenesis. We aimed to test the hypothesis that following macrocirculatory optimization, inhaled nitric oxide would improve microcirculation in patients with sepsis and that improved microcirculation would improve lactate clearance and multiple organ dysfunction. DESIGN: Randomized, sham-controlled clinical trial. SETTING: Single urban academic medical center. PATIENTS: Adult patients with severe sepsis and systolic blood pressure less than 90 mm Hg despite intravascular volume expansion and/or serum lactate greater than or equal to 4.0 mmol/L. INTERVENTIONS: After achievement of macrocirculatory resuscitation goals, we randomized patients to 6 hours of inhaled nitric oxide (40 ppm) or sham inhaled nitric oxide administration. We administered study drug via a specialized delivery device that concealed treatment allocation so that investigators and clinical staff remained blinded. MEASUREMENTS AND MAIN RESULTS: We performed sidestream dark-field videomicroscopy of the sublingual microcirculation prior to and 2 hours after study drug initiation. The primary outcome measure was the change in microcirculatory flow index. Secondary outcomes were lactate clearance and change in Sequential Organ Failure Assessment score. We enrolled 50 patients (28 of 50 [56%] requiring vasopressor agents; 15 of 50 [30%] died). Although inhaled nitric oxide significantly raised plasma nitrite levels, it did not improve microcirculatory flow, lactate clearance, or organ dysfunction. In contrast to previous studies conducted during the earliest phase of resuscitation, we found no association between changes in microcirculatory flow and lactate clearance or organ dysfunction. CONCLUSIONS: Following macrocirculatory optimization, inhaled nitric oxide at 40 ppm did not augment microcirculatory perfusion in patients with sepsis. Further, we found no association between microcirculatory perfusion and multiple organ dysfunction after initial resuscitation.

Arterial blood pressure and neurologic outcome after resuscitation from cardiac arrest*.

OBJECTIVES: Guidelines for post-cardiac arrest care recommend blood pressure optimization as one component of neuroprotection. Although some retrospective clinical studies suggest that postresuscitation hypotension may be harmful, and laboratory studies suggest that a postresuscitation hypertensive surge may be protective, empirical data are few. In this study, we prospectively measured blood pressure over time during the postresuscitation period and tested its association with neurologic outcome. DESIGN: Single center, prospective observational study from 2009 to 2012. PATIENTS: Inclusion criteria were age 18 years old or older, prearrest independent functional status, resuscitation from cardiac arrest, and comatose immediately after resuscitation. MEASUREMENTS AND MAIN RESULTS: Our research protocol measured blood pressure noninvasively every 15 minutes for the first 6 hours after resuscitation. We calculated the 0- to 6-hour time-weighted average mean arterial pressure and used multivariable logistic regression to test the association between increasing time-weighted average mean arterial pressures and good neurologic outcome, defined as Cerebral Performance Category 1 or 2 at hospital discharge. Among 151 patients, 44 (29%) experienced good neurologic outcome. The association between blood pressure and outcome appears to have a threshold effect at time-weighted average mean arterial pressure value of 70 mm Hg. This threshold (mean arterial pressure > 70 mm Hg) had the strongest association with good neurologic outcome (odds ratio, 4.11; 95% CI, 1.34-12.66; p = 0.014). A sustained intrinsic hypertensive surge was relatively uncommon and was not associated with neurologic outcome. CONCLUSIONS: We found that time-weighted average mean arterial pressure was associated with good neurologic outcome at a threshold of mean arterial pressure greater than 70 mm Hg.

Association between initial prescribed minute ventilation and post-resuscitation partial pressure of arterial carbon dioxide in patients with post-cardiac arrest syndrome.

BACKGROUND: Post-cardiac arrest hypocapnia/hypercapnia have been associated with poor neurological outcome. However, the impact of arterial carbon dioxide (CO2) derangements during the immediate post-resuscitation period following cardiac arrest remains uncertain. We sought to test the correlation between prescribed minute ventilation and post-resuscitation partial pressure of CO2 (PaCO2), and to test the association between early PaCO2 and neurological outcome. METHODS: We retrospectively analyzed a prospectively compiled single-center cardiac arrest registry. We included adult (age ≥ 18 years) patients who experienced a non-traumatic cardiac arrest and required mechanical ventilation. We analyzed initial post-resuscitation ventilator settings and initial arterial blood gas analysis (ABG) after initiation of post-resuscitation ventilator settings. We calculated prescribed minute ventilation:MVmL/kg/min=tidalvolumeTV/idealbodyweightIBWxrespiratoryrateRRfor each patient. We then used Pearson's correlation to test the correlations between prescribed MV and PaCO2. We also determined whether patients had normocapnia (PaCO2 between 30 and 50 mmHg) on initial ABG and tested the association between normocapnia and good neurological function (Cerebral Performance Category 1 or 2) at hospital discharge using logistic regression analyses. RESULTS: Seventy-five patients were included. The majority of patients were in-hospital arrests (85%). Pulseless electrical activity/asystole was the initial rhythm in 75% of patients. The median (IQR) TV, RR, and MV were 7 (7 to 8) mL/kg, 14 (14 to 16) breaths/minute, and 106 (91 to 125) mL/kg/min, respectively. Hypocapnia, normocapnia, and hypercapnia were found in 15%, 62%, and 23% of patients, respectively. Good neurological function occurred in 32% of all patients, and 18%, 43%, and 12% of patients with hypocapnia, normocapnia, and hypercapnia respectively. We found prescribed MV had only a weak correlation with initial PaCO2, R = -0.40 (P < 0.001). Normocapnia was associated with good neurological function, odds ratio 4.44 (95% CI 1.33 to 14.85). CONCLUSIONS: We found initial prescribed MV had only a weak correlation with subsequent PaCO2 and that early Normocapnia was associated with good neurological outcome. These data provide rationale for future research to determine the impact of PaCO2 management during mechanical ventilation in post-cardiac arrest patients.

Association between postresuscitation partial pressure of arterial carbon dioxide and neurological outcome in patients with post-cardiac arrest syndrome.

BACKGROUND: Partial pressure of arterial CO2 (Paco(2)) is a regulator of cerebral blood flow after brain injury. Recent guidelines for the management of cardiac arrest recommend maintaining Paco(2) at 40 to 45 mm Hg after successful resuscitation; however, there is a paucity of data on the prevalence of Paco(2) derangements during the post-cardiac arrest period and its association with outcome. METHODS AND RESULTS: We analyzed a prospectively compiled and maintained cardiac arrest registry at a single academic medical center. Inclusion criteria are as follows: age ≥18, nontrauma arrest, and comatose after return of spontaneous circulation. We analyzed arterial blood gas data during 0 to 24 hours after the return of spontaneous circulation and determined whether patients had exposure to hypocapnia and hypercapnia (defined as Paco(2) ≤30 mm Hg and Paco(2) ≥50 mm Hg, respectively, based on previous literature). The primary outcome was poor neurological function at hospital discharge, defined as Cerebral Performance Category ≥3. We used multivariable logistic regression, with multiple sensitivity analyses, adjusted for factors known to predict poor outcome, to determine whether post-return of spontaneous circulation hypocapnia and hypercapnia were independent predictors of poor neurological function. Of 193 patients, 52 (27%) had hypocapnia only, 63 (33%) had hypercapnia only, 18 (9%) had both hypocapnia and hypercapnia exposure, and 60 (31%) had no exposure; 74% of patients had poor neurological outcome. Hypocapnia and hypercapnia were independently associated with poor neurological function, odds ratio 2.43 (95% confidence interval, 1.04-5.65) and 2.20 (95% confidence interval, 1.03-4.71), respectively. CONCLUSIONS: Hypocapnia and hypercapnia were common after cardiac arrest and were independently associated with poor neurological outcome. These data suggest that Paco(2) derangements could be potentially harmful for patients after resuscitation from cardiac arrest.

Multiple organ dysfunction after return of spontaneous circulation in postcardiac arrest syndrome.

OBJECTIVES: Recent guidelines for the treatment of postcardiac arrest syndrome recommend optimization of vital organ perfusion after return of spontaneous circulation to reduce the risk of postresuscitation multiple organ injury. However, the prevalence of extracerebral multiple organ dysfunction in postcardiac arrest patients and its association with in-hospital mortality remain unclear. DESIGN: Single-center, prospective observational study. SETTING: Urban academic medical center. PATIENTS: Postcardiac arrest patients. Inclusion criteria were as follows: age older than 17 years, nontrauma cardiac arrest, and comatose after return of spontaneous circulation. INTERVENTIONS: We prospectively captured all extracerebral components of the Sequential Organ Failure Assessment score over the first 72 hours after return of spontaneous circulation. The primary outcome measure was in-hospital mortality. We used multivariate logistic regression to determine if multiple organ dysfunction (defined as the highest extracerebral Sequential Organ Failure Assessment score) was an independent predictor of death, after adjustment for the presence of cerebral injury (defined as not following commands at any point over 0-72 hr). MEASUREMENTS AND MAIN RESULTS: We enrolled 203 postcardiac arrest patients; 96% had some degree of extracerebral organ dysfunction and 66% had severe dysfunction in two or more extracerebral organ systems. The most common extracerebral organ failures were cardiovascular (i.e., vasopressor dependence) and respiratory (i.e., oxygenation impairment). The highest extracerebral Sequential Organ Failure Assessment score over 72 hours had an independent association with in-hospital mortality (odds ratio 1.95 [95% CI, 1.15-3.29]). Of the individual organ systems, only the cardiovascular and respiratory Sequential Organ Failure Assessment scores had an independent association with in-hospital mortality. CONCLUSIONS: The results of this study support the hypothesis that extracerebral organ dysfunction is common and associated with mortality in postcardiac arrest syndrome. This association appears to be driven by postresuscitation hemodynamic dysfunction and oxygenation impairment. Further research is needed to determine the value of hemodynamic and oxygenation optimization as a part of treatment strategies for patients with postcardiac arrest syndrome.

Nitric oxide donor agents for the treatment of ischemia/reperfusion injury in human subjects: a systematic review.

In animal models, administration of nitric oxide (NO) donor agents has been shown to reduce ischemia/reperfusion (I/R) injury. Our aim was to systematically analyze the biomedical literature to determine the effects of NO-donor agent administration on I/R injury in human subjects. We hypothesized that NO-donor agents reduce I/R injury. We performed a search of Cochrane Library, PubMed, CINAHL, conference proceedings, and other sources with no restriction to language using a comprehensive strategy. Study inclusion criteria were as follows: (a) human subjects, (b) documented periods of ischemia and reperfusion, (c) treatment arm composed of NO-donor agent administration, and (d) use of a control arm. We excluded secondary reports, reviews, correspondence, and editorials. We performed a qualitative analysis to collate and summarize treatment effects according to the recommended methodology from the Cochrane Handbook. Twenty-six studies involving multiple etiologies of I/R injury (10 cardiopulmonary bypass, six organ transplant, seven myocardial infarction, three limb tourniquet) met all inclusion and no exclusion criteria. Six (23%) of 26 were considered high-quality studies as per the Cochrane criteria for assessing risk of bias. In 20 (77%) of 26 studies and four (67%) of six high-quality studies, patients treated with NO-donor agents experienced reduced I/R injury compared with controls. Zero clinical studies to date have tested NO-donor agent administration in patients with cerebral I/R injury (e.g., cardiac arrest, stroke). Despite a paucity of high-quality clinical investigations, the preponderance of evidence to date suggests that administration of NO-donor agents may be an effective treatment for I/R injury in human subjects.

Emergency department inter-hospital transfer for post-cardiac arrest care: initial experience with implementation of a regional cardiac resuscitation center in the United States.

OBJECTIVE: The American Heart Association recently recommended regional cardiac resuscitation centers (CRCs) for post-resuscitation care following out-of-hospital cardiac arrest (OHCA). Our objective was to describe initial experience with CRC implementation. METHODS: Prospective observational study of consecutive post-resuscitation patients transferred from community Emergency Departments (EDs) to a CRC over 9 months. Transfer criteria were: OHCA, return of spontaneous circulation (ROSC), and comatose after ROSC. Incoming patients were received and stabilized in the ED of the CRC where advanced therapeutic hypothermia (TH) modalities were applied. Standardized post-resuscitation care included: ED evaluation for cardiac catheterization, TH (33-34 °C) for 24h, 24h/day critical care physician support, and evidence-based neurological prognostication. Prospective data collection utilized the Utstein template. The primary outcome was survival to hospital discharge with good neurological function [Cerebral Performance Category 1 or 2]. RESULTS: Twenty-seven patients transferred from 11 different hospitals were included. The majority (21/27 [78%]) had arrest characteristics suggesting poor prognosis for survival (i.e. asystole/pulseless electrical activity initial rhythm, absence of bystander cardiopulmonary resuscitation, or an unwitnessed cardiac arrest). The median (IQR) time from transfer initiation to reaching TH target temperature was 7(5-13)h. Ten (37%) patients survived to hospital discharge, and of these 9/10 (90% of survivors, 33% of all patients) had good neurological function. CONCLUSIONS: Despite a high proportion of patients with cardiac arrest characteristics suggesting poor prognosis for survival, we found that one-third of CRC transfers survived with good neurological function. Further research to determine if regional CRCs improve outcomes after cardiac arrest is warranted.

Therapeutic hypothermia and vasopressor dependency after cardiac arrest.

OBJECTIVE: Clinical trials of therapeutic hypothermia (TH) after cardiac arrest excluded patients with persistent hemodynamic instability after return of spontaneous circulation (ROSC), and thus equipoise may exist regarding use of TH in these patients. Our objective was to determine if TH is associated with worsening hemodynamic instability among patients who are vasopressor-dependent after ROSC. METHODS: We performed a prospective observational study in vasopressor-dependent post-cardiac arrest patients. Inclusion criteria were age >17, non-trauma cardiac arrest, comatose after ROSC, and persistent vasopressor dependence. The decision to initiate TH (33-34 ° C) was made by the treating physician. We measured cumulative vasopressor index (CVI) and mean arterial pressure (MAP) every 15 min during the first 6h after ROSC. The outcome measures were change in CVI (primary outcome) and MAP (secondary outcome) over time. We graphed median CVI and MAP over time for the treated and not treated cohorts, and used propensity adjusted repeated measures mixed models to test for an association between TH induction and change in CVI or MAP over time. RESULTS: Seventy-five post-cardiac arrest patients were included (35 treated; 40 not treated). We observed no major differences in CVI or MAP over time between the treated and not treated cohorts. In the mixed models we found no statistically significant association between TH induction and changes in CVI or MAP. CONCLUSION: In patients with vasopressor-dependency after cardiac arrest, the induction of hypothermia was not associated with a decrease in mean arterial pressure or increase in vasopressor requirement.

Discordance between microcirculatory alterations and arterial pressure in patients with hemodynamic instability.

PURPOSE: Recent studies reported that microcirculatory blood flow alterations occur in patients with circulatory shock independent of arterial pressure but typically lack baseline microcirculatory data before the insult and after recovery. We selected cardiopulmonary bypass (CPB) patients with expected and rapidly reversible hemodynamic instability to test the hypothesis that microcirculatory alterations can occur independent of mean arterial pressure (MAP). METHODS: Prospective observational study using sidestream darkfield videomicroscopy to measure sublingual microcirculatory flow preoperative (PRE), postoperatively after CPB (POST), and after recovery (REC). We determined the microcirculatory flow index (MFI) at each time point, blinded to all clinical data and compared change in MFI and MAP across time points using analysis of variance adjusted for multiple comparisons. RESULTS: We enrolled 20 subjects, 17 of 20 required inotrope/vasopressor agents at CPB discontinuation, 7 of 20 were on inotrope/vasopressor agents at the time of imaging, 20 of 20 were receiving continuous nitroglycerin. We observed an increase in post-CPB MFI (PRE, 2.16 ± 0.29; POST, 2.45 ± 0.62; REC, 2.26 ± 0.25; P < .01) without a concomitant increase in MAP. CONCLUSION: In this cohort of patients with hemodynamic instability, we observed discordance between microcirculatory blood flow and arterial pressure. These data support the concept that microcirculatory blood flow indices can yield physiologic information distinct from macrocirculatory hemodynamic parameters.

Purchase and use patterns of heroin users at an inner-city emergency department.

BACKGROUND: Many consider heroin abuse a problem of the inner city, but suburban patients may also be at risk. OBJECTIVE: To characterize the demographics and purchase/use patterns of heroin users in an inner-city emergency department (ED). METHODS: The study was conducted in one of the most impoverished and crime-ridden cities in the United States. Demographics and substance use habits of ED patients were prospectively collected. Patients who were<18 years of age, cognitively impaired, or did not speak English were excluded. Participants were further categorized as homeless, inner-city, and suburban residents. RESULTS: Of 3947 participants, 608 (15%) used an illicit substance in the past year, with marijuana (9%) and cocaine (6%) the most commonly used. Heroin ranked third, used by 180 (5%) participants, with 61% male, 31% black, and 20% Hispanic. There were 64 homeless, 60 suburban, and 56 inner-city heroin users. The most common route of use was injection (68%), with the highest rate in the homeless (84%). The majority of homeless and inner-city users bought (73%, both groups) and used (homeless 74%, inner city 88%) in the inner city. Of suburban users, 58% purchased and 61% used heroin in the inner city. Prescription narcotic use was more common in homeless (20%) and suburban (23%) heroin users than in inner-city users (9%) (p<0.001). CONCLUSIONS: Heroin is the third most commonly used illicit substance by ED patients, and a significant amount of inner-city purchase and use activity is conducted by suburban heroin users.

Impact of a teaching attending physician on medical student, resident, and faculty perceptions and satisfaction.

OBJECTIVES: To determine if a dedicated teaching attending for medical student education improves medical student, attending physician, and resident perceptions and satisfaction. METHODS: Two dedicated teaching attending physician shifts were added to the clinical schedule each week. A before-after trial compared medical student evaluations from 2000 to 2004 (preteaching attending physician) to medical student evaluations from 2005 to 2006 (teaching attending physician). Attending physician and resident perceptions and satisfaction with the teaching attending physician shifts using a 5-point Likert-type scale (1  =  poor to 5  =  excellent) were also assessed. RESULTS: Eighty-nine (100%) medical students participated, with 63 preteaching attending physician and 26 teaching attending physician rotation evaluations. The addition of teaching attending physician shifts improved mean medical student satisfaction with bedside teaching (4.1 to 4.5), lecture satisfaction (4.2 to 4.8), preceptor scores (4.3 to 4.8), and perceived usefulness of the rotation (4.5 to 5.0) (all p < 0.05). Thirteen attending physicians (93%) participated in the cross-sectional questionnaire. The addition of teaching attending physician shifts improved faculty ratings of their medical student interactions by ≥ 1.5 points for all items (p ≤ 0.001). Faculty perceptions of their resident interactions improved for quality of bedside teaching (3.1 to 4.0), their availability to hear resident presentations (3.4 to 4.2), and their supervision of residents (3.4 to 4.1) (p ≤ 0.01). Residents (n  =  35) noted minor improvements with the timeliness of patient dispositions, faculty bedside teaching, and attending physician availability. CONCLUSIONS: The addition of select teaching attending physician shifts had the greatest effect on medical student and faculty perceptions and satisfaction, with some improvements for residents.

Homespun remedy, homespun toxicity: baking soda ingestion for dyspepsia.

A 68-year-old man presented to the Emergency Department with a severe metabolic alkalosis after ingesting large quantities of baking soda to treat his dyspepsia. His underlying pulmonary disease and a progressively worsening mental status necessitated intubation for respiratory failure. Laboratory studies revealed a hyponatremic, hypochloremic, hypokalemic metabolic alkalosis. The patient was successfully treated after cessation of the oral bicarbonate, initiation of intravenous hydration, and correction of electrolyte abnormalities.

Ambulatory dysfunction due to unrecognized pernicious anemia.

Pernicious anemia can result in significant hematologic and neurologic impairments due to a reduction in cobalamin absorption. Typically thought to be a disease of elderly whites, a growing body of literature has documented the disease in blacks and in younger age groups. We describe a case of a young black woman with gradually progressive lower extremity paresthesias, weakness, and ataxia as the primary presenting symptoms of pernicious anemia. This case is presented to make emergency physicians aware of pernicious anemia as a cause of ambulatory dysfunction in younger patients. We review the current body of literature on the diagnosis and management as well as evidence that the demographic profile of the disease is changing. Furthermore, in women of reproductive age, there is the potential for significant fetal and infant morbidity.

Hyperglycemic emergencies in athletes.

Diabetes Mellitus is a chronic disorder affecting many adolescents and young adults participating in athletic activity at various levels. If blood glucose levels are managed incorrectly during periods of exercise, diabetes mellitus can lead to various endocrine emergencies, including hypoglycemia, hyperglycemia, and most seriously diabetic ketoacidosis. This article will review the epidemiology of diabetes mellitus, the body's response to exercise in a non-diabetic versus a diabetic, and the pathophysiology, clinical features, treatment, and prevention of hyperglycemic emergencies in athletes.

Point-of-care assessment of microvascular blood flow in critically ill patients.

OBJECTIVE: Sublingual microvascular videomicroscopy can assess tissue perfusion in critically ill patients; however, data analysis is currently limited to delayed off-line evaluation. We hypothesized that a real-time point-of-care (POC) determination of the microcirculatory flow index (MFI), an established metric for assessing microcirculatory perfusion, agrees well with the conventional off-line analysis. DESIGN: Prospective observational study. SETTING: Urban academic intensive care unit. PARTICIPANTS: A heterogeneous population of critically ill patients. MEASUREMENTS AND RESULTS: A single operator performed side stream darkfield videomicroscopy of the sublingual microcirculation and made a POC determination of MFI in real-time on a portable bedside monitor by assigning a score (0 = no flow to 3 = normal) to each quadrant of the image and averaging the four values. After image processing, de-identification and randomization, the same operator, blinded to the previous interpretation, repeated the MFI assessment by viewing an AVI-formatted image sequence on a 94 cm 1,080 pixel LCD monitor (reference standard). There were 205 paired measurements in 18 subjects. The POC and reference standard MFI had good agreement by Bland-Altman analysis [mean difference of -0.031, SD = 0.198 (95% CI, -0.43 to 0.37)]. The POC assessment was 94% sensitive and 92% specific for detecting impaired microvascular flow (defined a priori as an MFI < 2.5 based on previously published data). CONCLUSIONS: A POC determination of MFI had good agreement with conventional off-line analysis, and was highly sensitive and specific for detecting impaired microvascular flow. This real-time technique may be useful in future clinical trials targeting impaired microcirculatory perfusion in critically ill patients.

Early arterial hypotension is common in the post-cardiac arrest syndrome and associated with increased in-hospital mortality.

AIM: After return of spontaneous circulation (ROSC) from cardiac arrest, profound myocardial stunning and systemic inflammation may cause hemodynamic alterations; however, the prevalence of post-ROSC hemodynamic instability and the strength of association with outcome have not been established. We tested the hypothesis that exposure to arterial hypotension after ROSC occurs commonly (>50%) and is an independent predictor of death. METHODS: Single-center retrospective cohort study of all post-cardiac arrest patients over 1 year. INCLUSION CRITERIA: (1) age >17; (2) non-trauma; (3) sustained ROSC after cardiac arrest. Using the Jones criteria, subjects were assigned to one of two groups based on the presence of hypotension within 6h after ROSC: (1) exposures-two or more systolic blood pressures (SBPs) <100mmHg or (2) non-exposures-less than two SBP <100mmHg. The primary outcome was in-hospital mortality. We compared mortality rates between groups and used multivariate logistic regression to determine if post-ROSC hypotension independently predicted death. RESULTS: 102 subjects met inclusion criteria. In-hospital mortality was 75%. Exposure to hypotension occurred in 66/102 (65%) and was associated with significantly higher mortality (83%) compared to non-exposures (58%, p=0.01). In a model controlling for common confounding variables (age, pre-arrest functional status, arrest rhythm, and provision of therapeutic hypothermia (HT)), early exposure to hypotension was a strong independent predictor of death (OR 3.5 [95% CI 1.3-9.6]). CONCLUSIONS: Early exposure to arterial hypotension after ROSC was common and an independent predictor of death. These data suggest that post-ROSC hypotension could potentially represent a therapeutic target in post-cardiac arrest care.

Asynchrony between left and right lungs in acute asthma.

BACKGROUND: Asthma is a disease of air flow obstruction. Transmitted sounds can be analyzed in detail and may shed light upon the physiology of asthma and how it changes over time. The goals of this study were to use a computerized analytic acoustic tool to evaluate respiratory sound patterns in asthmatic patients during acute attacks and after clinical improvement and to compare asthmatic profiles with those of normal individuals. METHODS: Respiratory sound analysis throughout the respiratory cycle was performed on 22 symptomatic asthma patients at the time of presentation to the emergency department (ED) and after clinical improvement. Fifteen healthy volunteers were analyzed as a control group. Vibrations patterns were plotted. Right and left lungs were analyzed separately. RESULTS: Asthmatic attacks were found to be correlated with asynchrony between lungs. In normal subjects, the inspiratory and expiratory vibration energy peaks (VEPs) occurred almost simultaneously in both lungs; the time interval between right and left expiratory VEPs was 0.006 +/- 0.012 seconds. In symptomatic asthmatic patients on admission, the time interval between right and left expiratory VEPs was 0.14 +/- 0.09 seconds and after clinical improvement the interval decreased to 0.04 +/- 0.04 seconds. Compared to healthy volunteers, asynchrony between two lungs was increased in asthmatics (p < 0.05). The asynchrony was significantly reduced after clinical improvement (p < 0.05). CONCLUSIONS: Respiratory sound analysis demonstrated significant asynchrony between right and left lungs in asthma exacerbations, a finding which, to our knowledge, has never been reported to date. The asynchrony is significantly reduced with clinical improvement following treatment.