Xavier Bobbia

Respiratory variations of inferior vena cava diameter to predict fluid responsiveness in spontaneously breathing patients with acute circulatory failure: need for a cautious use

IntroductionTo investigate whether respiratory variation of inferior vena cava diameter (cIVC) predict fluid responsiveness in spontaneously breathing patients with acute circulatory failure (ACF).MethodsForty patients with ACF and spontaneous breathing were included. Response to fluid challenge was defined as a 15% increase of subaortic velocity time index (VTI) measured by transthoracic echocardiography. Inferior vena cava diameters were recorded by a subcostal view using M Mode. The cIVC was calculated as follows: (Dmax - Dmin/Dmax) × 100 and then receiver operating characteristic (ROC) curves were generated for cIVC, baseline VTI, E wave velocity, E/A and E/Ea ratios.ResultsAmong 40 included patients, 20 (50%) were responders (R). The causes of ACF were sepsis (n = 24), haemorrhage (n = 11), and dehydration (n = 5). The area under the ROC curve for cIVC was 0.77 (95% CI: 0.60-0.88). The best cutoff value was 40% (Se = 70%, Sp = 80%). The AUC of the ROC curves for baseline E wave velocity, VTI, E/A ratio, E/Ea ratio were 0.83 (95% CI: 0.68-0.93), 0.78 (95% CI: 0.61-0.88), 0.76 (95% CI: 0.59-0.89), 0.58 (95% CI: 0.41-0.75), respectively. The differences between AUC the ROC curves for cIVC and baseline E wave velocity, baseline VTI, baseline E/A ratio, and baseline E/Ea ratio were not statistically different (p = 0.46, p = 0.99, p = 1.00, p = 0.26, respectively).ConclusionIn spontaneously breathing patients with ACF, high cIVC values (>40%) are usually associated with fluid responsiveness while low values (< 40%) do not exclude fluid responsiveness.

Ultrasound guidance for radial arterial puncture: a randomized controlled trial

UNLABELLED STUDY OBJECTIVE AND BACKGROUND: Arterial puncture for blood gas analysis is a frequent procedure and could be difficult in the emergency setting. The aim of the study was to compare ultrasonographically guided arterial radial puncture vs conventional sampling. MATERIALS AND METHODS This is a prospective, randomized study. The inclusion criteria are all patients needing arterial blood gas at admission in the emergency unit. The exclusion criteria are the following: Hallen test positive, local sepsis, local trauma, known sever local arteriopathy, refusal of consent by the patient, participation in another study, and cardiac arrest. Patients were randomized into 2 groups: radial arterial puncture obtained through an ultrasonographically guided technique (group 1) or radial arterial puncture by conventional method (group 2). The main objective is the number of attempts after enrollment. The secondary objectives are time to success, patient satisfaction and pain, and physician satisfaction. Immediate complications were collected. Groups were compared with nonparametric analysis. RESULTS The data were usable for 72 of 74 patients included. Lung disease (acute exacerbation of chronic obstructive pulmonary disease and pneumonia) at 45% (n = 32) and suspicion of pulmonary embolism in 31% (n = 22) were the most common reasons. Demographics data were comparable in the 2 groups. In group 1, the number of attempts significantly increased (2.35 [1-3] vs 1.66 [1-2] [P = .017]), and the sample was 2.4 times longer (132 seconds [50-200] vs 55 [20-65] [P < .01] by standard method). There was no significant difference in terms of pain (visual analog scale [VAS], 3.6 [2-5] for both groups [P = .743]), patient satisfaction (VAS, 7.2 [5-9] vs 6.8 [5-9] [P = .494]), and physician satisfaction (VAS, 6.0 [3.5-8] vs 6.9 [5-9] [P = .233]). No immediate complications were found in the 2 groups. CONCLUSION Ultrasonographically guided arterial puncture increases the number and duration of implementations. This technique, however, does not alter the patients pain, the number of immediate complications, or patient and physician satisfaction.

Influence of Diaphragmatic Motion on Inferior Vena Cava Diameter Respiratory Variations in Healthy Volunteers

Background:The collapsibility index of inferior vena cava (cIVC) is widely used to decide fluid infusion in spontaneously breathing intensive care unit patients. The authors hypothesized that high inspiratory efforts may induce false-positive high cIVC values. This study aims at determining a value of diaphragmatic motion recorded by echography that could predict a high cIVC (more than or equal to 40%) in healthy volunteers. Methods:The cIVC and diaphragmatic motions were recorded for three levels of inspiratory efforts. Right and left diaphragmatic motions were defined as the maximal diaphragmatic excursions. Receiver operating characteristic curves evaluated the performance of right diaphragmatic motion to predict a cIVC more than or equal to 40% defining the best cutoff value. Results:Among 52 included volunteers, interobserver reproducibility showed a generalized concordance correlation coefficient (&rgr;c) above 0.9 for all echographic parameters. Right diaphragmatic motion correlated with cIVC (r = 0.64, P < 0.0001). Univariate analyses did not show association between cIVC and age, sex, weight, height, or body mass index. The area under the receiver operating characteristic curves for cIVC more than or equal to 40% was 0.87 (95% CI, 0.81 to 0.93). The best diaphragmatic motion cutoff was 28 mm (Youden Index, 0.65) with sensitivity of 89% and specificity of 77%. The gray zone area was 25 to 43 mm. Conclusions:Inferior vena cava collapsibility is affected by diaphragmatic motion. During low inspiratory effort, diaphragmatic motion was less than 25 mm and predicted a cIVC less than 40%. During maximal inspiratory effort, diaphragmatic motion was more than 43 mm and predicted a cIVC more than 40%. When diaphragmatic motion ranged from 25 to 43 mm, no conclusion on cIVC value could be done.

Transcranial Doppler to Predict Neurologic Outcome after Mild to Moderate Traumatic Brain Injury

Background:To assess the performance of transcranial Doppler (TCD) in predicting neurologic worsening after mild to moderate traumatic brain injury. Methods:The authors conducted a prospective observational study across 17 sites. TCD was performed upon admission in 356 patients (Glasgow Coma Score [GCS], 9 to 15) with mild lesions on cerebral computed tomography scan. Normal TCD was defined as a pulsatility index of less than 1.25 and diastolic blood flow velocity higher than 25 cm/s in the two middle cerebral arteries. The primary endpoint was secondary neurologic deterioration on day 7. Results:Twenty patients (6%) developed secondary neurologic deterioration within the first posttraumatic week. TCD thresholds had 80% sensitivity (95% CI, 56 to 94%) and 79% specificity (95% CI, 74 to 83%) to predict neurologic worsening. The negative predictive values and positive predictive values of TCD were 98% (95% CI, 96 to 100%) and 18% (95% CI, 11to 28%), respectively. In patients with minor traumatic brain injury (GCS, 14 to 15), the sensitivity and specificity of TCD were 91% (95% CI, 59 to 100%) and 80% (95% CI, 75 to 85%), respectively. The area under the receiver operating characteristic curve of a multivariate predictive model including age and GCS was significantly improved with the adjunction of TCD. Patients with abnormal TCD on admission (n = 86 patients) showed a more altered score for the disability rating scale on day 28 compared to those with normal TCD (n = 257 patients). Conclusions:TCD measurements upon admission may provide additional information about neurologic outcome after mild to moderate traumatic brain injury. This technique could be useful for in-hospital triage in this context. (Anesthesiology 2016; 125:346-54)

Does physician experience influence the interpretability of focused echocardiography images performed by a pocket device

IntroductionThe use of focused cardiac ultrasound (FoCUS) in a prehospital setting is recommended. Pocket ultrasound devices (PUDs) appear to be well suited to prehospital FoCUS. The main aim of our study was to evaluate the interpretability of echocardiography performed in a prehospital setting using a PUD based on the experience of the emergency physician (EP).MethodsThis was a monocentric prospective observational study. We defined experienced emergency physicians (EEPs) and novice emergency physicians (NEPs) as echocardiographers if they had performed 50 echocardiographies since their initial university training (theoretical training and at least 25 echocardiographies performed with a mentor). Each patient undergoing prehospital echocardiography with a PUD was included. Four diagnostic items based on FoCUS were analyzed: pericardial effusions (PE), right ventricular dilation (RVD), qualitative left ventricular function assessment (LVEF), and inferior vena cava compliance (IVCC). Two independent experts blindly evaluated the interpretability of each item by examining recorded video loops. If their opinions were divided, then a third expert concluded.ResultsFourteen EPs participated: eight (57 %) EEPs and six (43 %) NEPs. Eighty-five patients were included: 34 (40 %) had an echocardiography by an NEP and 51 (60 %) by an EEP. The mean number of interpretable items by echocardiography was three [1; 4]; one [0; 2.25] in the NEP group, four [3; 4] in EEP (p < .01). The patient position was also associated with interpretable items: supine three [2; 4], “45°” three [1; 4], sitting two [1; 4] (p = .02). In multivariate analysis, only EP experience was associated with the number of interpretable items (p = .02). Interpretability by NEPs and EEPs was: 56 % vs. 96 % for LVF, 29 % vs. 98 % for PE, 26 % vs. 92 % for RVD, and 21 % vs. 67 % for IVCC (p < .01 for all).ConclusionFoCUS with PUD in prehospital conditions was possible for EEPs, It is difficult and the diagnostic yield is poor for NEPs.

Lactic acidosis as a complication of β-adrenergic aerosols

Lactic acidosis is a marker of tissue hypoperfusion and impairs oxygen delivery. High lactate levels are associated with altered systemic hemodynamics, tissue hypoperfusion, and altered cellular metabolism. Increased lactate levels have also been reported as a complication of β-adrenergic agents administered during asthma therapy. A 49-year-old woman with a prior diagnosis of asthma presented to the emergency department in respiratory distress. She immediately received, in 2 hours, 4 bronchodilator aerosols (ipratropium bromide 0.5 mg/2 mL and terbutaline 5 mg/2 mL) and methylprednisolone intravenous (120 mg). After these 4 aerosols, she was still dyspneic. First, arterial blood gases (pH 7.38; PCO2, 3.92 kPa; HCO3, 19.2 mmol/L) and arterial lactate (lactate, 7.96 mmol/L) were performed with a second series of 4 aerosols. Second, arterial blood gases (pH 7.29; PCO2, 4.01 kPa; HCO3, 15.4 mmol/L) and arterial lactate (lactate, 10.47 mmol/L) were performed at the end of the second series of aerosols. There was no hypoxemia, no inadequate cardiac output state, no anemia, no sepsis, and no use of biguanides. Previous studies have suggested that administration of β agonists can lead to lactic acidemia in the absence of hypoxia or shock, but it is the highest level of lactate that we found in the literature. In sepsis and shock, lactic acidosis is used as a marker of disease severity. In this case, it is not necessarily the sign of an immediate gravity.

The Influence of Arm Positioning on Ultrasonic Visualization of the Subclavian Vein: An Anatomical Ultrasound Study in Healthy Volunteers.

We hypothesized that placing the arm in 90° abduction, through 90° flexion and 90° external rotation, could improve ultrasound visualization of the subclavian vein. In 49 healthy volunteers, a single operator performed a view of the subclavian vein in neutral position and abduction position. A second blinded operator measured the cross-sectional area of the subclavian vein. Abduction position increased the cross-sectional area of the subclavian vein from 124 ± 46 (mean ± SD) to 162 ± 58 mm2 (P = 0.001). An increase of the cross-sectional area of ≥50% was observed in 41% volunteers (95% confidence interval, 27%–56%, n = 20); this technique offers an alternative approach (maybe safer) for ultrasound-guided catheterization of the subclavian vein.

Comparison of Miller and Airtraq laryngoscopes for orotracheal intubation by physicians wearing CBRN protective equipment during infant resuscitation: a randomized crossover simulation study

BackgroundThe purpose of this study was to evaluate the performance of orotracheal intubation with the Miller laryngoscope compared with the Airtraq laryngoscope by emergency and pediatric physicians wearing CBRN-PPE type III on infant manikins with conventional airway. We hypothesized that in this situation, the orotracheal intubation with the Airtraq laryngoscope would be faster and more effective than with the Miller laryngoscope.MethodsThis was a prospective, randomized, crossover, single-center study who recruited emergency department physicians on a voluntary basis. Each physician performed a total of 20 intubation trials while in CBRN-PPE with the two intubation techniques, Miller and Airtraq. Intubations by each airway device were tested over ten consecutive runs. The order of use of one or the other devices was randomized with a ratio of 1:1. The primary endpoint was overall orotracheal intubation success.ResultsFifty-five emergency and pediatric physicians were assessed for eligibility. Forty-one physicians were included in this study and 820 orotracheal intubation attempts were performed. The orotracheal intubation success rate with the Airtraq laryngoscope was higher than with the Miller (99 % vs. 92 %; p-adjusted <.001). The orotracheal intubation and glottis visualization times decreased with the number of attempts (p <.001). The median orotracheal intubation time with the Airtraq laryngoscope was lower than with the Miller laryngoscope (15 s vs. 20 s; p-adjusted <.001). The median glottis visualization time with the Airtraq laryngoscope and with the Miller laryngoscope were not different (6.0 s vs. 7.5 s; p-adjusted =.237). Thirty-four (83 %) physicians preferred the Airtraq laryngoscope versus 6 (15 %) for the Miller (p-adjusted <.001).DiscussionFor tracheal intubation by physicians wearing CBRN-PPE during infant resuscitation simulation, we showed that the orotracheal intubation success rate with the Airtraq laryngoscope was higher than with the Miller laryngoscope and that orotracheal intubation time with the Airtraq laryngoscope was lower than with the Miller laryngoscope.ConclusionsIt seems useful to train the physicians in emergency departments in the use of pediatric Airtraq and for the management of CBRN risks.

Collinearity and multivariable analysis

We read with interest the article by Martin‐Loeches et al. entitled “Determinants of time to death in hospital in critically ill patients around the world” [1]. In this article, the authors aimed to investigate which factors influence time to death in hospital in critically ill patients worldwide. They found that time to death in hospital is longer in older patients, surgical patients, and patients with infection. We congratulate the authors for this valuable study. To obtain these results, the authors performed a multivariable analysis using a multilevel multinomial logistic model. Among the explanatory variables considered in the model, we found SAPS II and age. However, SAPS II uses a point score based upon initial values of 17 variables included age or type of admission [2]. Unfortunately, collinearity occurs when there are high correlations among variables. In this situation, the coefficient estimates of the regression can change capriciously in response to small changes in the model or the data. Thus, the coefficient estimates are unstable and very difficult to interpret. I wonder if the authors can reassure us concerning a possible collinearity bias between SAPS II and age, type of admission, or the other explanatory variables used in the model?

Diaphragmatic excursion measurement in emergency patients with acute dyspnea: toward a new diagnostic tool?

INTRODUCTION During acute dyspnea (AD), respiratory exhaustion is mainly due to diaphragm fatigue. The primary objective was to validate interobserver reproducibility of diaphragmatic excursion (DE) in emergency department (ED) patients admitted for AD. The secondary objectives were to assess the feasibility of DE measurement and intraobserver reproducibility. Finally, we examined whether the DE value was associated with a need for noninvasive ventilation (NIV). MATERIALS This was a monocentric, prospective, technical reproducibility study. Adult patients in spontaneous ventilation admitted for AD were included. Two operators carried out 2 consecutive diaphragm excursion measurements each on the right and left hemidiaphragms. RESULTS Twenty-four patients were analyzed. The feasibility was 96% on the right and 67% on the left. The interobserver concordance between the 2 measures was 0.80 (95% confidence interval [CI], 0.59-0.91) (average difference, -0.07±0.48 cm) on the right and 0.59 (95% CI, 0.19-0.82) (average difference, 0.30±0.91 cm) on the left. For right DE values inferior to 2.3 cm, the interobserver concordance between measures was 0.92 (95% CI, 0.78-0.97). The intraobserver concordance was 0.89 (95% CI, 0.81-0.94) (average difference, 0.02±0.35 cm) on the right and 0.90 (95% CI, 0.82-0.95) (average difference,-0.06±0.45 cm) on the left. When the DE was greater than 2 cm, no patient required NIV. CONCLUSION Diaphragmatic excursion measurement of the right diaphragm is feasible, with good interobserver and intraobserver reproducibility in ED patients admitted for AD. When the DE value is greater than 2 cm at admission, no subsequent NIV is required.