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Background: Targeted temperature management is a standard therapy for unconscious survivors of cardiac arrest. To date, multiple cooling methods are available including invasive intravascular cooling devices (IVDs), which are widely used in the clinical setting. Recently, esophageal heat exchangers (EHEs) have been developed providing cooling via the esophagus that is located close to the aorta and inferior vena cava. The objective was to compare mean cooling rates, as well as differences, to target temperature during maintenance and the rewarming period of IVD and EHE., Methods: The study was conducted in 16 female domestic pigs. After randomization to either IVD or EHE (n = 8/group), core body temperature was reduced to 33°C. After 24 hours of maintenance (33°C), animals were rewarmed using a target rate of 0.25°C/h for 10 hours. All cooling phases were steered by a closed-loop feedback system between the internal jugular vein and the chiller. After euthanasia, laryngeal and esophageal tissue was harvested for histopathological examination., Results: Mean cooling rates (4.0°C/h ± 0.4°C/h for IVD and 2.4°C/h ± 0.3°C/h for EHE; P < .0008) and time to target temperature (85.1 ± 9.2 minutes for IVD and 142.0 ± 21.2 minutes for EHE; P = .0008) were different. Mean difference to target temperature during maintenance (0.07°C ± 0.05°C for IVD and 0.08°C ± 0.10°C for EHE; P = .496) and mean rewarming rates (0.2°C/h ± 0.1°C/h for IVD and 0.3°C/h ± 0.2°C/h for EHE; P = .226) were similar. Relevant laryngeal or esophageal tissue damage could not be detected. There were no significant differences in undesired side effects (eg, bradycardia or tachycardia, hypokalemia or hyperkalemia, hypoglycemia or hyperglycemia, hypotension, overcooling, or shivering)., Conclusions: After insertion, target temperatures could be reached faster by IVD compared to EHE. Cooling performance of IVD and EHE did not significantly differ in maintaining target temperature during a targeted temperature management process and in active rewarming protocols according to intensive care unit guidelines in this experimental setting.

Background: The Smart Bag MO(R) is an adult flow-limited bag-valve device designed to reduce the risk of stomach inflation in an unprotected airway. Its properties in severe airway obstruction are as yet unknown., Methods: In a bench model, we evaluated respiratory mechanics and delivered tidal volumes although ventilating at airway resistances of 4, 10, and 20 cm H(2)O . L(-1) . s(-1) once with a flow-limited bag-valve device and once with a standard bag-valve device to simulate a respiratory arrest patient with an unprotected airway., Results: Inspiratory times were always longer with the flow-limited bag-valve device than with the standard bag-valve device. Lung tidal volume in the simulated unobstructed airway was 750 +/- 70 mL using the flow-limited bag-valve device versus 780 +/- 30 mL using the standard bag-valve device (n.s.); in the simulated medium obstructed airway it was 800 +/- 70 versus 850 +/- 20 mL (n.s.), and in the simulated severely obstructed airway it was 210 +/- 20 versus 170 +/- 10 mL (P < 0.01). Peak airway pressure in the simulated unobstructed airway was 15 +/- 2 cm H(2)O using the flow-limited bag-valve device versus 22 +/- 4 cm H(2)O using the standard bag-valve device (P < 0.01); in the simulated medium obstructed airway it was 22 +/- 1 versus 39 +/- 7 cm H(2)O (P < 0.01), and in the simulated severely obstructed airway it was 26 +/- 1 versus 61 +/- 3 cm H(2)O (P < 0.01). Stomach inflation in the simulated unobstructed airway was 0 mL/min using both bag-valve devices; in the simulated medium obstructed airway it was 0 mL/min for the flow-limited bag-valve device versus 200 +/- 20 mL/min for the standard bag-valve device (P < 0.01), and in the simulated severely obstructed airway it was 0 versus 1240 +/- 50 mL/min (P < 0.01)., Conclusion: In a simulated severely obstructed unprotected airway, the use of a flow-limited bag-valve device resulted in longer inspiratory times, higher tidal volumes, lower inspiratory pressures, and no stomach inflation compared with a standard bag-valve device.

In severe airway hemorrhage, simultaneous suction and laryngoscopy may render intubation difficult. We built a suction laryngoscope that consists of an adjustable stainless steel-guide tube fixed at the lingual surface of a standard Macintosh laryngoscope blade. Via this steel-guide tube, a large suction catheter can be inserted and positioned exactly to suction pharyngeal blood or vomitus, rendering simultaneous suctioning and laryngoscopy possible. In contrast to previous suction laryngoscopes, our suction catheter has a large lumen, which enables fast suctioning and exact placement by adjusting the steel-guide tube. To assess whether our suction laryngoscope could provide better intubation conditions in comparison to a standard Macintosh laryngoscope in a bleeding airway scenario, 44 medical students intubated a manikin with severe simulated airway hemorrhage using our suction laryngoscope and a standard Macintosh laryngoscope in random order. There was no significant difference in time needed for intubation when using the suction versus the Macintosh laryngoscope (mean +/- SD: 43 +/- 13 vs 52 +/- 31 s; P = 0.07), but the number of esophageal intubations was significantly lower when using the suction laryngoscope [6 of 44 (13.6%) vs 19 of 44 (43.2%); P = 0.004]. In conclusion, when compared with a standard Macintosh laryngoscope, using a suction laryngoscope did not result in more rapid intubation, but significantly decreased the likelihood of esophageal intubations.

In a bench model, we evaluated a bag-valve device (Smart Bag MO) with limited maximum inspiratory gas flow developed to reduce the risk of stomach inflation in an unprotected airway. During simulated cardiopulmonary resuscitation with uninterrupted chest compressions, ventilation with the "disabled" Smart Bag MO or an adult self-inflating bag-valve device provided only adequate tidal volumes if inspiratory time was 0.5 s. Ventilation with the "enabled" Smart Bag MO, even in ventilation windows of 0.5 s, provided inadequate tidal volumes during simulated cardiopulmonary resuscitation and would result in hypoventilation in a patient.

Unlabelled: In a porcine model of uncontrolled hemorrhagic shock, we evaluated the effects of vasopressin versus an equal volume of saline placebo versus fluid resuscitation on hemodynamic variables and short-term survival. Twenty-one anesthetized pigs were subjected to severe liver injury. When mean arterial blood pressure was <20 mm Hg and heart rate decreased, pigs randomly received either vasopressin IV (0.4 U/kg; n = 7), an equal volume of saline placebo (n = 7), or fluid resuscitation (1000 mL each of lactated Ringer's solution and hetastarch; n = 7). Thirty minutes after intervention, surviving pigs were fluid resuscitated while bleeding was surgically controlled. Mean (+/- SEM) arterial blood pressure 5 min after the intervention was significantly (P < 0.05) higher after vasopressin than with saline placebo or fluid resuscitation (58 +/- 9 versus 7 +/- 3 versus 32 +/- 6 mm Hg, respectively). Vasopressin improved abdominal organ blood flow but did not cause further blood loss (vasopressin versus saline placebo versus fluid resuscitation 10 min after intervention, 1343 +/- 60 versus 1350 +/- 22 versus 2536 +/- 93 mL, respectively; P < 0.01). Seven of 7 vasopressin pigs survived until bleeding was controlled and 60 min thereafter, whereas 7 of 7 saline placebo and 7 of 7 fluid resuscitation pigs died (P < 0.01). We conclude that vasopressin, but not saline placebo or fluid resuscitation, significantly improves short-term survival during uncontrolled hemorrhagic shock., Implications: Although IV fluid administration is the mainstay of nonsurgical management of trauma patients with uncontrolled hemorrhagic shock, the efficacy of this strategy has been discussed controversially. In this animal model of severe liver trauma with uncontrolled hemorrhagic shock, vasopressin, but not saline placebo or fluid resuscitation, improved short-term survival.

Unlabelled: During normothermic cardiac arrest, a combination of active compression-decompression (ACD) cardiopulmonary resuscitation (CPR) with the inspiratory threshold valve (ITV) significantly improves vital organ blood flow, but this technique has not been studied during hypothermic cardiac arrest. Accordingly, we evaluated the hemodynamic effects of ACD + ITV CPR before, and after, the administration of vasopressin in a porcine model of hypothermic cardiac arrest. Pigs were surface-cooled until their body core temperature was 26 degrees C. After 10 min of untreated ventricular fibrillation, 14 animals were randomly assigned to either ACD CPR with the ITV (n = 7) or to standard (STD) CPR (n = 7). After 8 min of CPR, all animals received 0.4 U/kg vasopressin IV, and CPR was maintained for an additional 10 min in each group; defibrillation was attempted after 28 min of cardiac arrest, including 18 min of CPR. Before the administration of vasopressin, mean +/- SEM common carotid blood flow was significantly higher in the ACD + ITV group compared with STD CPR (67 +/- 13 versus 26 +/- 5 mL/min, respectively; P < 0.025). After vasopressin was given at minute 8 during CPR, mean +/- SEM coronary perfusion pressure was significantly higher in the ACD + ITV group, but did not increase in the STD group (29 +/- 3 versus 15 +/- 2 mm Hg, and 25 +/- 1 versus 14 +/- 1 mm Hg at minute 12 and 18, respectively; P < 0.001); mean +/- SEM common carotid blood flow remained higher at respective time points (33 +/- 8 versus 10 +/- 3 mL/min, and 31 +/- 7 versus 7 +/- 3 mL/min, respectively; P < 0.01). Without active rewarming, spontaneous circulation was restored and maintained for 1 h in three of seven animals in the ACD + ITV group versus none of seven animals in the STD CPR group (not significant). During hypothermic cardiac arrest, ACD CPR with the ITV improved common carotid blood flow compared with STD CPR alone. Moreover, after the administration of vasopressin, coronary perfusion pressure was significantly higher during ACD + ITV CPR, but not during STD CPR., Implications: New strategies are needed to improve the efficiency of cardiopulmonary resuscitation (CPR) in hypothermic cardiac arrest. Active compression-decompression CPR with the inspiratory threshold valve improved carotid blood flow (and coronary perfusion pressure with vasopressin) compared with standard CPR.