Matej Strnad

Combination of lung ultrasound (a comet-tail sign) and N-terminal pro-brain natriuretic peptide in differentiating acute heart failure from chronic obstructive pulmonary disease and asthma as cause of acute dyspnea in prehospital emergency setting

IntroductionWe studied the diagnostic accuracy of bedside lung ultrasound (the presence of a comet-tail sign), N-terminal pro-brain natriuretic peptide (NT-proBNP) and clinical assessment (according to the modified Boston criteria) in differentiating heart failure (HF)-related acute dyspnea from pulmonary (chronic obstructive pulmonary disease (COPD)/asthma)-related acute dyspnea in the prehospital setting.MethodsOur prospective study was performed at the Center for Emergency Medicine, Maribor, Slovenia, between July 2007 and April 2010. Two groups of patients were compared: a HF-related acute dyspnea group (n = 129) and a pulmonary (asthma/COPD)-related acute dyspnea group (n = 89). All patients underwent lung ultrasound examinations, along with basic laboratory testing, rapid NT-proBNP testing and chest X-rays.ResultsThe ultrasound comet-tail sign has 100% sensitivity, 95% specificity, 100% negative predictive value (NPV) and 96% positive predictive value (PPV) for the diagnosis of HF. NT-proBNP (cutoff point 1,000 pg/mL) has 92% sensitivity, 89% specificity, 86% NPV and 90% PPV. The Boston modified criteria have 85% sensitivity, 86% specificity, 80% NPV and 90% PPV. In comparing the three methods, we found significant differences between ultrasound sign and (1) NT-proBNP (P < 0.05) and (2) Boston modified criteria (P < 0.05). The combination of ultrasound sign and NT-proBNP has 100% sensitivity, 100% specificity, 100% NPV and 100% PPV. With the use of ultrasound, we can exclude HF in patients with pulmonary-related dyspnea who have positive NT-proBNP (> 1,000 pg/mL) and a history of HF.ConclusionsAn ultrasound comet-tail sign alone or in combination with NT-proBNP has high diagnostic accuracy in differentiating acute HF-related from COPD/asthma-related causes of acute dyspnea in the prehospital emergency setting.Trial registrationClinicalTrials.gov NCT01235182.

Erythropoietin facilitates the return of spontaneous circulation and survival in victims of out-of-hospital cardiac arrest

BACKGROUND Erythropoietin activates potent protective mechanisms in non-hematopoietic tissues including the myocardium. In a rat model of ventricular fibrillation, erythropoietin preserved myocardial compliance enabling hemodynamically more effective CPR. OBJECTIVE To investigate whether intravenous erythropoietin given within 2 min of physician-led CPR improves outcome from out-of-hospital cardiac arrest. METHODS Erythropoietin (90,000 IU of beta-epoetin, n=24) was compared prospectively with 0.9% NaCl (concurrent controls=30) and retrospectively with a preceding group treated with similar protocol (matched controls=48). RESULTS Compared with concurrent controls, the erythropoietin group had higher rates of ICU admission (92% vs 50%, p=0.004), return of spontaneous circulation (ROSC) (92% vs 53%, p=0.006), 24-h survival (83% vs 47%, p=0.008), and hospital survival (54% vs 20%, p=0.011). However, after adjusting for pretreatment covariates only ICU admission and ROSC remained statistically significant. Compared with matched controls, the erythropoietin group had higher rates of ICU admission (92% vs 65%, p=0.024) and 24-h survival (83% vs 52%, p=0.014) with statistically insignificant higher ROSC (92% vs 71%, p=0.060) and hospital survival (54% vs 31%, p=0.063). However, after adjusting for pretreatment covariates all four outcomes were statistically significant. End-tidal PCO(2) (an estimate of blood flow during chest compression) was higher in the erythropoietin group. CONCLUSIONS Erythropoietin given during CPR facilitates ROSC, ICU admission, 24-h survival, and hospital survival. This effect was consistent with myocardial protection leading to hemodynamically more effective CPR (Trial registration: http://isrctn.org. Identifier: ISRCTN67856342).

Point of care ultrasound for orotracheal tube placement assessment in out-of hospital setting

AIM OF THE STUDY The percentage of unrecognised orotracheal tube displacement in an out-of-hospital setting has been reported to be between 4.8% and 25%. The aim of our study was to assess the sensitivity and specificity of Point-of-Care-UltraSound (POCUS) for confirming the proper tube position after an urgent orotracheal intubation in an out-of-hospital setting and the time needed for POCUS. METHODS Our single-centred prospective study included all patients who needed out-of-hospital orotracheal intubation. After the intubation, bilateral chest auscultation and assessment of bilateral lung sliding and diaphragm excursion within POCUS were done. Spectrographic quantitative capnography was used as the reference standard to confirm a proper tube position. RESULTS We enrolled 124 patients. For auscultation, sensitivity and negative predicted value were 100%, specificity was 90% and positive predicted value 30% (95% confidence interval). Sensitivity, specificity, positive predicted value, and negative predicted value for POCUS alone and for a combination of auscultation and POCUS were 100% (95% confidence interval). In three patients, we detected endobronchial tube displacement with auscultation and POCUS. Capnography failed to detect displacement in all three cases. The median time needed for POCUS was 30s. CONCLUSION Results of our study support POCUS as an accurate and reliable method for confirming the proper orotracheal tube placement in trachea and it is feasible for out-of-hospital setting implementation. POCUS also seems to be time saving method but to make definitive conclusion more studies should be done.

Identification of lung sliding: a basic ultrasound technique with a steep learning curve

Introduction. One of the basic premises of sonographic lung imaging is the concept of lung sliding. Identification of clear lung sliding excludes pneumothorax (PTx) at that specific local point.Methods. Fifty-seven 4th year medical students were given a 20-minute lecture on sonographic identification of lung sliding and exclusion of PTx. After the lecture, students were asked to correctly position the probe, identify shown structures and on each attempt (six attempts in a row) state whether lung sliding is present or not.Results. There were 57 students in the sample. Fifty students (87.7%) successfully positioned the probe (all 4 positions) for PTx identification. All but five students (91.2%) recognized the anatomic structures of the thorax. Mean number of correctly identified cases per student was 5.1 ± 1.1. In 292 (85.4%) cases, the answer was correct. In 298 (87.1%) cases, students were confident in the correct answer. Students who were confident in the right answer gave the right answer significantly more often when compared to others (90.3% vs. 52.3%, p < 0.001). Sensitivity of this method for 4th year medical students was 82.6% and its specificity was 87.9%. For correct identification of lung sliding in the sixth attempt, students on average needed 4.5 correct attempts.Conclusion. Our study suggests that 4th year medical students with no prior experience in lung ultrasonography can easily acquire knowledge and skills needed to detect thoracic wall structures and identify lung sliding with a high degree of sensitivity and specificity.

Predictors of mortality in patients with isolated severe traumatic brain injury

SummaryBackgroundTraumatic brain injury (TBI) is a leading cause of death and disability worldwide. Many prognostic models predicting mortality in patients with TBI were developed, which also include patients with mild or moderate TBI and patients who suffered major extracranial injuries.MethodsFrom a prospective database, we conducted a retrospective medical chart review covering the period between January 2000 and December 2012 of patients with isolated severe TBI (Abbreviated Injury Score for head, AISH ≥ 3) without extracranial injuries, who were intubated in the field using the rapid sequence intubation method and were of age 16 or more. Prehospital vital signs, Injury Severity Score (ISS) and laboratory tests were compared in two study groups: survivors (n = 25) and non-survivors (n = 27). Selected variables identified during univariate analysis (p < 0.1) were then subjected to multivariate analysis logistic regression model.ResultsUnivariate analysis showed that in-hospital mortality was statistically significantly associated with male sex (p = 0.040), ISS (p = 0.005) and mydriasis (p = 0.012). For predicting mortality, area under the curve (AUC) was calculated: for ISS 0.76 (95 % confidence interval, CI; 0.63–0.90; p < 0.001) and for initial Glasgow Coma Scale (GCS) 0.64 (95 % CI, 0.49–0.80, p = 0.079). In the multivariate analysis, ISS (odds ratio, OR; 1.19, 95 % CI, 1.06–1.35; p = 0.004) and mydriasis (OR, 5.73; 95 % CI, 1.06–30.88; p = 0.042) were identified as independent risk factors for in-hospital mortality. The AUC for the regression model was 0.83 (95 % CI, 0.71–0.94; p < 0.001).ConclusionsIn prehospital intubated patients with isolated severe TBI only ISS and mydriasis were found to be independent predictors of in-hospital mortality.

Cerebral tissue oximetry levels during prehospital management of cardiac arrest – A prospective observational study

INTRODUCTION Near-infrared spectroscopy (NIRS) enables continuous monitoring of regional oximetry (rSO2). The aim of this study was to describe dynamics of regional cerebral oximetry levels during out of hospital cardiac arrest (OHCA) resuscitation, specifically around the time of restoration of spontaneous circulation (ROSC). METHODS This prospective observational study was performed in the prehospital setting during cardio-pulmonary resuscitation (CPR) of OHCA patients. In the three-year study period, two-hundred eighty OHCAs were responded to; rSO2 was continuously measured throughout CPR and after attaining ROSC. RESULTS Final data analysis included 53 patients. Continuous rSO2dynamics were described and data was compared amongst ROSC (22 cases) and no-ROSC (31 cases) groups. Initial rSO2levels were below 15% (not detectable) in both groups. With ongoing CPR, rSO2levels were higher in the ROSC group (median 22% vs. 14% in no-ROSC group, p = 0.030). Until ROSC, rSO2levels were higher throughout CPR before ROSC (mean maximal value 47% at ROSC vs. 31% no-ROSC, p < 0.01). Furthermore, we found a pattern of significant, rapid and sustained rise in rSO2levels minutes prior to ROSC and normalization thereafter. CONCLUSIONS Initial rSO2levels during OHCA are generally undetectable by the time EMS teams initiate CPR. With CPR, rSO2levels rise and are higher during CPR in patients who later achieve ROSC. Patients who achieve ROSC exhibit significant, rapid, and sustained rise in rSO2minutes prior to attaining ROSC, and normalization of rSO2 levels thereafter. Persistently low levels of rSO2 during CPR likely portend poor neurologic outcomes.

Arterial blood gas changes during cardiac arrest and cardiopulmonary resuscitation combined with passive oxygenation/ventilation: a METI HPS study

Objective High-fidelity simulators can simulate physiological responses to medical interventions. The dynamics of the partial arterial pressure of oxygen (PaO2), partial arterial pressure of carbon dioxide (PaCO2), and oxygen pulse saturation (SpO2) during simulated cardiopulmonary resuscitation (CPR) were observed and compared with the results from the literature. Methods Three periods of cardiac arrest were simulated using the METI Human Patient Simulator™ (Medical Education Technologies, Inc., Sarasota, FL, USA): cardiac arrest, chest compression-only CPR, and chest compression-only CPR with continuous flow insufflation of oxygen (CFIO). Results In the first period, the observed values remained constant. In the second period, PaCO2 started to rise and peaked at 63.5 mmHg. In the CFIO period, PaCO2 slightly fell. PaO2 and SpO2 declined only in the second period, reaching their lowest values of 44 mmHg and 70%, respectively. In the CFIO period, PaO2 began to rise and peaked at 614 mmHg. SpO2 exceeded 94% after 2 minutes of CFIO. Conclusions The METI Human Patient Simulator™ accurately simulated the dynamics of changes in PaCO2. Use of this METI oxygenation model has some limitations because the simulated levels of PaO2 and SpO2 during cardiac arrest correlate poorly with the results from published studies.

Impact of pre-hospital oxygenation and ventilation status on outcome in patients with isolated severe traumatic brain injury

ABSTRACT Introduction. Hypoxia is one of the secondary insults and it worsens the outcome in patients with severe traumatic brain injury (TBI). On the other hand, there is some controversy about the impact of hyperoxia on the outcome in these patients. The aim of the study was to determine the impact of pre-hospital hypoxia, hyperoxia and pre-hospital ventilation status on outcome after isolated TBI.Methods. We retrospectively reviewed charts from patients with isolated severe TBI who underwent pre-hospital endotra-cheal intubation. The population was sorted into groups based on PaO2 (hypoxic, PaO2 200 mmHg) and initial Glasgow Coma Scale (GCS) level (3-5 and ≥ 6). Ventilation status was defined as: hypocarbic (PaCO2 45 mmHg). Results. Oxygenation status had no significant impact on 24- and 48-hour survival, on the length of hospital stay or on neuro-logical outcome (measured by the Glasgow Outcome Scale (GOS), Glasgow Pittsburgh Cerebral Performance Categories Scale (CPC), and GCS score at discharge) when all six groups were compared together. We were unable to prove a dele-terious effect of hypoxia or hyperoxia compared to normoxia on rate of survival to hospital discharge (STHD) (0.38 (0.52) vs 0.50 (0.51) vs 0.65 (0.49), where 0 - no and 1 - yes; f = 1.246, p = 0.298). Ventilation status also failed to significantly af fect survival and functional outcome in patients with isolated severe TBI.Conclusion. Pre-hospital oxygenation and ventilation status have no significant impact on outcome in patients with isolated severe TBI.