Raphaël Briot

Outcome after severe accidental hypothermia in the French Alps: A 10-year review

OBJECTIVE To describe the factors associated with outcome after accidental deep hypothermia. METHODS We conducted a retrospective cohort study on patients with accidental hypothermia (core temperature <28 °C) admitted to a Level I emergency room over a 10-year period. RESULTS Forty-eight patients were included with a median temperature of 26 °C (range, 16.3-28 °C) on admission. The etiology of hypothermia was exposure to a cold environment (n = 27), avalanche (n = 13) or immersion in cold water (n = 8). Mean age was 47 ± 22 years, and 58% were males. Thirty-two patients had a cardiac arrest (CA): 15 patients presented unwitnessed cardiac arrest (UCA) and 17 patients presented rescue collapse (RC). Extracorporeal life support (ECLS) was implemented in 21 patients with refractory cardiac arrest and in two patients with hemodynamic instability. Overall mortality was 50%. For cardiac arrest patients, only three out of 15 patients with UCA survived at day 28, whereas eight out of 17 patients with RC survived. The cerebral performance category score was 4 for all the survivors of UCA and 1 [range, 1-2] for survivors of RC. Patients with poor outcome presented more UCA, a lower pH, a higher serum potassium, creatinine, serum sodium or lactate level as well as more severe coagulation disorders. CONCLUSION Cardiac arrest related to rescue collapse was associated with favorable outcome. On-scene rescue collapse should prompt prolonged resuscitation and ECLS rewarming in all CA patients with deep hypothermia. Conversely, unwitnessed cardiac arrest was associated with unfavorable outcome and will likely not benefit from ECLS.

Increased cardiac index due to terbutaline treatment aggravates capillary-alveolar macromolecular leakage in oleic acid lung injury in dogs

IntroductionWe assessed the in vivo effects of terbutaline, a beta2-agonist assumed to reduce microvascular permeability in acute lung injury.MethodsWe used a recently developed broncho-alveolar lavage (BAL) technique to repeatedly measure (every 15 min. for 4 hours) the time-course of capillary-alveolar leakage of a macromolecule (fluorescein-labeled dextran) in 19 oleic acid (OA) lung injured dogs. BAL was performed in a closed lung sampling site, using a bronchoscope fitted with an inflatable cuff. Fluorescein-labeled Dextran (FITC-D70) was continuously infused and its concentration measured in plasma and BAL fluid. A two-compartment model (blood and alveoli) was used to calculate KAB, the transport rate coefficient of FITC-D70 from blood to alveoli. KAB was estimated every 15 minutes over 4 hours. Terbutaline intra-venous perfusion was started 90 min. after the onset of the injury and then continuously infused until the end of the experiment.ResultsIn the non-treated injured group, the capillary-alveolar leakage of FITC-D70 reached a peak within 30 minutes after the OA injury. Thereafter the FITC-D70 leakage decreased gradually until the end of the experiment. Terbutaline infusion, started 90 min after injury, interrupted the recovery with an aggravation in FITC-D70 leakage.ConclusionsAs cardiac index increased with terbutaline infusion, we speculate that terbutaline recruits leaky capillaries and increases FITC-D70 leakage after OA injury. These findings suggest that therapies inducing an increase in cardiac output and a decrease in pulmonary vascular resistances have the potential to heighten the early increase in protein transport from plasma to alveoli within the acutely injured lung.

Deliberate drug poisoning with slight symptoms on admission: Are there predictive factors for intensive care unit referral? A three-year retrospective study

Deliberate drug poisoning leads to 1% of emergency department (ED) admissions. Even if most patients do not exhibit any significant complication, 5% need to be referred to an intensive care unit (ICU). Emergency physicians should distinguish between low‐ and high‐acuity poisoned patients at an early stage to avoid excess morbidity. Our aim was to identify ICU transfer factors in deliberately self‐poisoned patients without life‐threatening symptoms on admission. We performed a 3‐year retrospective observational study in a university hospital. Patients over 18 years of age with a diagnosis of deliberate drug poisoning were included. Clinical and toxicological data were analysed with univariate tests between groups (ED stay versus ICU transfer). Factors associated with ICU admission were then included in a logistic regression analysis. Two thousand five hundred and sixty‐five patients were included. 63.2% were women, and median age was 40 (28–49). 142 patients (5.5%) were transferred to ICU. Cardiac drugs [adjusted OR (aOR) = 19.81; 95% confidence interval (95% CI): 7.93–49.50], neuroleptics (aOR = 2.78; 95% CI: 1.55–4.97) and meprobamate (aOR = 2.71; 95% CI: 1.27–5.81) ingestions were significantly linked to ICU admission. A presumed toxic dose ingestion (aOR = 2.27; 95% CI: 1.28–4.02), number of ingested tablets (aOR = 1.01; 95% CI: 1.01–1.02 for each tablet) and delay between ingestion and ED arrival <2 hr (aOR = 2.85; 95%CI: 1.62–5.03) were also factors for ICU referral. The Glasgow Coma Scale was the only clinical feature associated with ICU admission (aOR = 1.57; 95% CI: 1.44–1.70 for each point loss). These results suggest that emergency physicians should pay particular attention to toxicological data on ED admission to distinguish between low‐ and high‐acuity self‐poisoned patients.

Monitoring the Capillary-Alveolar Leakage in an A.R.D.S. Model Using Broncho-Alveolar Lavage

Objectives: We developed a modified broncho‐alveolar lavage (BAL) technique in order to perform repeated measurements of capillary‐alveolar leakage of a macromolecule in oleic acid (OA)‐induced lung injury.

Advanced normothermic ex vivo lung maintenance using the mobile Organ Care System

To the Editor: A 39-year-old woman with cerebral hemorrhage was mechanically ventilated for 6 days prior to organ retrieval. No immediate-match local recipient was available but donor lung functional assessment showed a PaO2/FIO2 311 and favorable chest X-ray and bronchoscopy findings. The donor lungs were used experimentally to test for extended perfusion ex vivo, after harvesting with routine Perfadex flush. The main pulmonary artery and the trachea were cannulated, while the left atrial cuff was left to drain freely into the chamber of mobile a Organ Care System (OCS). The perfusate consisted of 1 liter of Steen solution and leukocyte-depleted packed red blood cells (RBCs), with adjustment of hematocrit to a range of 20% to 25% at a temperature of 37°C. Graft function was assessed by two integrated methods in the OCS. The first method involves continuous de-oxygenation of the perfusate through a gas exchanger while ventilating the lungs with room air. Venous and arterial saturations were monitored and blood samples taken for routine blood-gas analysis. The second method involves de-oxygenation of the perfusate followed by a timed reoxygenation with room-air ventilation.

Effects of cyclosporine a in ex vivo reperfused pig lungs.

Several works highlight the role of CsA in the prevention of IRI, but none focus on isolated lungs. Our objective was to evaluate the effects of CsA on IRI on ex vivo reperfused pig lungs.

A Wearable Technology Revisited for Cardio-Respiratory Functional Exploration: Stroke Volume Estimation from Respiratory Inductive Plethysmography

The objective of the present study is to extract new information from complex signals generated by Respiratory Inductive Plethysmography (RIP). This indirect cardio-respiratory (CR) measure is a well-known wearable solution. The authors applied time-scale analysis to estimate cardiac activity from thoracic volume variations, witnesses of CR interactions. Calibrated RIP signals gathered from 4 healthy volunteers in resting conditions are processed by Ensemble Empirical Mode Decomposition to extract cardiac volume signals and estimate stroke volumes. Averaged values of these stroke volumes (SVRIP) are compared with averaged values of stroke volumes determined simultaneously by electrical impedance cardiography (SVICG). There is a satisfactory correlation between SVRIP and SVICG (r=0.76, p

Deep Hypothermic Cardiac Arrest Treated by Extracorporeal Life Support in a Porcine Model: Does the Rewarming Method Matter?

OBJECTIVES Extracorporeal life support (ECLS) is the reference rewarming technique of accidental deep hypothermic cardiac arrest (DHCA). This study was designed to examine the impact of different rewarming blood flow rates and temperature setting of ECLS on cardiopulmonary lesions after DHCA in a porcine model of accidental hypothermia. METHODS Twenty-four pigs were cannulated for ECLS, cooled until DHCA occurred, and subjected to 30 minutes of cardiac arrest. During the rewarming phase, we compared a low blood flow rate of 1.5 L/min versus a high flow rate of 3.0 L/min as well as two-temperature-setting rewarming strategies: a temperature during ECLS adjusted to 5°C above the central core temperature versus 38°C maintained throughout the rewarming phase. Cardiac output, hemodynamics and pulmonary function parameters were evaluated. Biologic markers of ischemia-reperfusion injuries were analyzed at baseline and at the end of the experiment. RESULTS DHCA occurred at 21.2 ± 2°C. There was a trend for better cardiac output in groups with high blood flow (p = 0.053), with no interaction between ECLS flow and temperature (p = 0.63), a trend toward lower pulmonary vascular resistance (PVR; p = 0.075) and a significant decrease in arterial PVR in groups with high blood flow (p = 0.013) with no interaction (p = 0.47 and p = 0.60 for PVR and arterial PVR, respectively). Serum interleukin-6, tumor necrosis factor-α, receptor for advanced glycation end products (RAGE), and neuron-specific enolase were significantly increased between baseline and endpoint. The increase in the serum RAGE concentration was higher in the 38°C rewarming temperature groups compared to 5°C above adjusted temperature. There were no other significant differences in biomarkers. CONCLUSIONS We developed a porcine model of DHCA treated by ECLS. Our data suggest that cardiac output tended to improve with a high-flow-rate rewarming strategy while a high-temperature delta between core temperature and ECLS increased the RAGE markers of lung injury.

Real-time measurements of endogenous carbon monoxide production in isolated pig lungs.

Abstract. Ischemia-reperfusion injuries are a critical determinant of lung transplantation success. The endogenous production of carbon monoxide (CO) is triggered by ischemia-reperfusion injuries. Our aim was, therefore, to assess the feasibility of exhaled CO measurements during the ex vivo evaluation of lungs submitted to ischemia-reperfusion injuries. Five pigs were euthanized and their lungs removed after pneumoplegia. After cold storage (30 min, 4°C), the lungs were connected to an extracorporeal membrane oxygenation circuit, slowly warmed-up, and ventilated. At the end of a 45-min steady state, CO measurements were performed by optical-feedback cavity-enhanced absorption spectroscopy, a specific laser-based technique for noninvasive and real-time low gas concentration measurements. Exhaled CO concentration from isolated lungs reached 0.45±0.19  ppmv and was above CO concentration in ambient air and in medical gas. CO variations peaked during the expiratory phase. Changes in CO concentration in ambient air did not alter CO concentrations in isolated lungs. Exhaled CO level was also found to be uncorrelated to heme oxygenase (HO-1) gene expression. These results confirm the feasibility of accurate and real-time CO measurement in isolated lungs. The presented technology could help establishing the exhaled CO concentration as a biomarker of ischemia-reperfusion injury in ex vivo lung perfusion.

Exhaled carbon monoxide is correlated with ischemia reperfusion injuries during ex vivo lung perfusion in pigs

Measurement of exhaled carbon monoxide (eCO) might help in the selection of lung grafts during ex vivo lung perfusion (EVLP) since its endogenous production is increased under ischemia reperfusion. The objective of this study was to measure eCO variations depending on the extent of lung ischemia reperfusion injuries. Using a porcine model and a laser spectrometer instrument, eCO was measured during EVLP. eCO was compared after 30 min (D0) or 24 h (D1) of cold ischemia. The ability of eCO to distinguish lungs deemed suitable for transplantation was evaluated. Six lungs were studied at D0 and compared to six lungs studied at D1. eCO was systematically higher on D1 (1.35 ± 0.26 ppmv versus 0.95 ± 0.31 ppmv, p = 0.01). The best threshold concentration for eCO to select lungs was 0.86 ppmv (area under the receiver operating characteristic curve: 0.65 [95% confidence interval: 0.34-0.97], p = 0.40). These results show that eCO varies during EVLP. The interpretation of this variation and the role of eCO as a biomarker of ischemia reperfusion injuries during EVLP should be tested in further clinical studies.