Differences in the thermal properties and surface temperature of prehospital antihypothermia devices: an in vitro study.

BACKGROUND: Preventing and treating hypothermia in prehospital settings is crucial. Several products have been developed to prevent heat loss and actively warm patients in prehospital settings. We compared the efficacy and the surface temperature of different antihypothermia products, using a fluid-based model at two ambient temperatures. METHODS: We tested five active (Blizzard Heat with active pads, Ready-Heat, Ready-Heat-II, Hypothermia Prevention and Management Kit (HPMK), Bair Hugger) and five passive (Blizzard Heat, Heat Reflective Shell, sleeping bag, 'space blanket', wool blanket) antihypothermia products. A torso model consisting of four 8 L bags of fluid preheated to 36°C±0.5°C (97±0.5°F) was used to compare the devices' performances at 20°C (68°F) and 8°C (46°F). Inner and surface temperatures were recorded for up to 480 min. RESULTS: We found significant differences in heat loss in fluid bags among the tested devices at both temperatures (p<0.001). At 20°C, only HPMK and Ready-Heat-II increased the inner temperature for 480 min while Blizzard Heat with active pads prevented heat loss. Ready-Heat prevented heat loss for 90 min. All the other devices did not prevent heat loss beyond 30 min. At 8°C, none of the products heated the model. Bair Hugger, HPMK, Ready-Heat II and sleeping bag prevented heat loss for 30 min. At 60, 90 and 120 min HPMK, Ready-Heat II and Bair Hugger were the most effective. Over 480 min, Bair Hugger was most effective, with a heat loss of 2.3°C±0.4°C. The surface temperature exceeded 44°C (111°F) for all the exothermic warming devices when used for a prolonged period of time. CONCLUSION: At 20°C, HPMK and Ready-Heat-II increased fluid temperature in the model, while the other devices decreased heat loss. At 8°C, none of the tested devices increased the temperature. However, active heating devices prevented heat loss slightly better than passive methods. A protective insulation layer should be used with all active heating blankets.

Effect of Prolonged Hypothermic Cardiopulmonary Bypass, Heparin, and Protamine on Platelet: A Small-Group Study.

Cardiopulmonary bypass (CPB) is associated with platelet dysfunction (PD), an important cause of postoperative bleeding. The etiology of PD is not completely understood. We mapped the platelets' function during CPB to determine the etiology of PD. Platelets activation, measured by procaspase activating compound-1 and P-selectin expression (CD62P), after activation by adenosine diphosphate and thrombin receptor activator peptide, were decreased by protamine. Changes during CPB were insignificant. Platelet-leukocyte aggregation was increased by CPB but not by protamine. Platelet apoptosis marker, annexin V, was increased by protamine. Changes during CPB were insignificant. Our findings demonstrate that protamine given after CPB plays a central role in PD and count decrease.

[ANESTHETIC DRUGS IN CHILDREN AND PREGNANT WOMEN - IMPLICATIONS OF THE RECENT FDA WARNING].

INTRODUCTION: Recent animal studies demonstrated neuronal apoptosis following early life exposure to most anesthetic drugs. Further research into this question demonstrated neonatal neuronal damage in multiple species (including primates) and evidence that this damage has cognitive and social sequela. These results raised the suspicion that general anesthesia in neonates, infants and pregnant women may injure the developing brain. Follow-up human studies were inconclusive. Retrospective studies suffer from tremendous selection bias due to the surgical effect and the baseline condition that required the surgical intervention. A number of large retrospective studies yield contradicting results, leaving the issue unsettled. Results of new, high quality prospective studies suggest that a short, single exposure does not lead to any measurable damage, but we are still awaiting final long term results. Despite the inconclusive evidence, the American Food and Drug Administration (FDA) published a warning mandating drug manufacturers to disclose the risk with the package insert, and clinicians to discuss the possible risks with the parents or the pregnant woman before the planned procedure. The European Society of Anesthesiologists, as well as the Israeli Society of Anesthesiologists, did not adopt this FDA policy. Despite the possible uncertain risk, it was decided that the evidence is inconclusive in regards to clinical human scenarios. It was agreed that such warnings would lead to delaying necessary procedures based on unfounded information. It was therefore decided to avoid changing the informed consent form and consent process until further information is available.

Comparison of the performance of battery-operated fluid warmers.

OBJECTIVES: Warming intravenous fluids is essential to prevent hypothermia in patients with trauma, especially when large volumes are administered. Prehospital and transport settings require fluid warmers to be small, energy efficient and independent of external power supply. We compared the warming properties and resistance to flow of currently available battery-operated fluid warmers. METHODS: Fluid warming was evaluated at 50, 100 and 200 mL/min at a constant input temperature of 20°C and 10°C using a cardiopulmonary bypass roller pump and cooler. Output temperature was continuously recorded. RESULTS: Performance of fluid warmers varied with flows and input temperatures. At an input temperature of 20°C and flow of 50 mL/min, the Buddy Lite, enFlow, Thermal Angel and Warrior warmed 3.4, 2.4, 1 and 3.6 L to over 35°C, respectively. However, at an input temperature of 10°C and flow of 200 mL/min, the Buddy Lite failed to warm, the enFlow warmed 3.3 L to 25.7°C, the Thermal Angel warmed 1.5 L to 20.9°C and the Warrior warmed 3.4 L to 34.4°C (p<0.0001). CONCLUSION: We found significant differences between the fluid warmers: the use of the Buddy Lite should be limited to moderate input temperature and low flow rates. The use of the Thermal Angel is limited to low volumes due to battery capacity and low output temperature at extreme conditions. The Warrior provides the best warming performance at high infusion rates, as well as low input temperatures, and was able to warm the largest volumes in these conditions.

Orthopedic Activity in Field Hospitals Following Earthquakes in Nepal and Haiti : Variability in Injuries Encountered and Collaboration with Local Available Resources Drive Optimal Response.

BACKGROUND: Field hospitals have been deployed by the Israel Defense Forces (IDF) Medical Corps in numerous disaster events. Two recent deployments were following earthquakes in Haiti in 2010 and in Nepal in 2015. Despite arrival in similar timetables, the mode of operation was different-independently in Haiti and in collaboration with a local hospital in Nepal. The pathology encountered in the two hospitals and the resultant treatment requirements were significantly different between the two events. The purpose of this study was to analyze these differences and their implications for preparation and planning of future deployments. METHODS: Data were obtained from IDF records and analyzed using SPSS™ software. RESULTS: 1686 patients were treated in Nepal versus 1111 in Haiti. The caseload in Nepal included significantly less earthquake-related injuries (26 vs. 66 %) with 28 % of them sustaining fractures versus 47 % in Haiti. Femoral fractures accounted for 7.9 % of fractures in Nepal versus 26.4 % in Haiti with foot fractures accounting for 23.8 and 6.4 %, respectively. The rate of open fracture was similar at 29.4 % in Nepal and 27.5 % in Haiti. 18.1 % of injured patients in Nepal underwent surgery, and 32.9 % of which was skeletal compared to 32 % surgical cases (58.8 % skeletal) in Haiti. 74.2 % of patients in Nepal and 34.3 % in Haiti were treated for pathology unrelated to the earthquake. CONCLUSIONS: The reasons for the variability in activities between the two hospitals include the magnitude of the disaster, the functionality of the local medical system which was relatively preserved in Nepal and destroyed in Haiti and the mode of operation which was independent in Haiti and collaborative with a functioning local hospital in Nepal. Emergency medical teams (EMTs) may encounter variable caseloads despite similar disaster scenarios. Advance knowledge of the magnitude of the disaster, the functionality of the local medical system, and the collaborative possibilities will help in planning and preparing EMTs to function optimally and appropriately. However, as this information will often be unavailable, EMTs should be capable to adapt to unexpected conditions.

Skin electrical resistance does not change following infraclavicular block.

Peripheral nerve blocks are common and effective means for anesthesia for limb surgery. The evaluation of the success of a peripheral blockade is based on the loss of sensation, with no objective means of detecting a successful block. The autonomic innervation to the upper extremity, which controls both the vascular tone and the activity of sweat glands, is supplied by nerve fibers accompanying the somatic nerve fibers. Previous studies have shown changes in both skin temperature and electrical resistance of the skin following brachial plexus block. We studied 20 patients undergoing hand surgery under infraclavicular brachial plexus block. The electrical resistance of the skin on the palmar aspect of the forearm was continuously recorded on the block arm and on the contralateral arm using a commercial skin resistance monitor. No statistically significant change in the electrical resistance of the skin was observed during 20 minutes after placement of the block. These results strongly suggest that the electrical resistance of the skin cannot be used to predict a successful infraclavicular block.

Subarachnoid block with hyperbaric bupivacaine and morphine may shorten PACU stay after cesarean delivery.

Spinal anesthesia for cesarean delivery is a widely used modality. Both hyperbaric and isobaric bupivacaine are in clinical use, with or without the addition of opioids, but the baricity of intrathecal bupivacaine has not been correlated with recovery time after cesarean delivery. One hundred parturients scheduled for elective cesarean delivery were randomly divided into four groups: hyperbaric bupivacaine (10 mg), hyperbaric bupivacaine (10 mg) with morphine (100 mcg), isobaric bupivacaine (10 mg), and isobaric bupivacaine (10 mg) with morphine (100 mcg). All groups received additional intrathecal fentanyl 15 mcg. Recovery from motor block, postoperative nausea and vomiting, and postoperative pain, as well as analgesic requirements were documented. The four groups did not differ in the rate of intraoperative and postoperative adverse effects. Parturients receiving hyperbaric bupivacaine recovered from motor block earlier and were less likely to require analgesic supplements, thus meeting PACU discharge criteria sooner. The addition of intrathecal morphine did not significantly delay postoperative recovery or discharge from the PACU and further reduced analgesic requirements. Spinal anesthesia with hyperbaric bupivacaine 10 mg with or without morphine 100 mcg provided faster, less painful recovery compared with either isobaric bupivacaine with or without morphine when added to fentanyl 15 mcg, enabling faster discharge from the PACU.

One-minute heart rate variability - an adjunct for airway obstruction identification.

Heart rate variability (HRV) reflects cardiac and autonomic nervous system activity. It is usually measured over a relatively prolonged period and presented using multiple parameters. Here, we studied rapid HRV changes during airway obstruction using a short (1 min) sampling window. Forty healthy volunteers underwent a trial of obstructed breathing. Heart rate was recorded during three consecutive sets comprised of 1-min control followed by 1 min of obstructed breathing, with 1 min of rest between sets. Time and frequency domain analysis were used to compare HRV during control versus obstructed breathing. Compared with control, HRV intensely increased during obstructed breathing: R-R intervals (time between consecutive R waves) standard deviation increased from 65 to 108 msec (P < 0.0001), root mean square of successive R-R interval from 61 to 82 msec (P = 0.001), number of pairs of successive R-R intervals that differ by more than 50 msec (NN50) from 16.5 to 25.3 events (P < 0.0001), and proportion of NN50 divided by total number of R-R intervals from 26.6 to 35.1% (P = 0.001). Low frequency power increased by more than fourfold (P < 0.0001), allowing 90% sensitivity and 75% specificity for identifying airway obstruction (ROC area 0.88, P < 0.0001). We observed a rapid intense increase in HRV during obstructed breathing, significant enough to detect during a short 1-min sampling window. These findings suggest that HRV may be useful for rapid detection of airway obstruction, especially in situations where end-tidal CO2 monitoring is not optimal, such as during partial airway obstruction.

Three-step management of a newborn with a giant, highly vascularized, cervical teratoma: a case report.

BACKGROUND: A giant congenital cervical teratoma is often highly vascularized; thus, in addition to a life-threatening airway occlusion at birth it comprises a high risk for significant and lethal blood loss during resection. In the case presented, an endovascular embolization of the carotid artery that supplied a giant congenital cervical teratoma was done as part of a three-stage treatment soon after birth and contributed to an overall good outcome. Embolization in cases of cervical teratomas was not described previously. CASE PRESENTATION: We present a case of a preterm newborn from a Sephardic jewish origin with a giant, highly vascularized, congenital cervical teratoma that was managed successfully in three stages: (1) delivery by an ex utero intrapartum treatment procedure after extensive preoperative planning and followed by tracheostomy, (2) endovascular embolization of the carotid artery that supplied the tumor in order to decrease blood loss during resection, and (3) complete surgical resection. The parents were involved in all the ethical and medical decisions, starting just after the cervical mass was diagnosed prenatally. CONCLUSION: The management of giant congenital cervical teratoma is often challenging from both a medical and ethical prospective. Meticulous perinatal planning and parents' involvement is crucial. Endovascular embolization of the tumor feeding vessels can significantly improve the resection outcome and overall prognosis.

[Retrograde tracheal intubation--an alternative in difficult airway management].

Secured airway is a must in spontaneous or assisted ventilation. A variety of methods are in clinical use for establishing an airway, of which endotracheal intubation is the most common. Difficulties in establishing a secured airway may deteriorate to a serious, and even a life-threatening situation. The management of difficult airways indicates the use of advanced, urgent means, and may lead to surgical intervention. This article describes an alternative technique for tracheal intubation, useful in such cases. Retrograde tracheal intubation is carried out by percutaneous insertion of a needle into the trachea in the subglotic region, passing a guidewire through the needle cephaled until it exits the mouth or nose and threading an endotracheal tube over the guidewire into the trachea. This technique is relatively easy and safe, and should be considered in difficult airway management.

[Marijuana smoking and paroxysmal atrial fibrillation].

INTRODUCTION: Cannabis is the most widely used illegal drug in Israel, and unlike most of the other illegal drugs, it is common among segments of the population with higher demographic characteristics. CASE REPORT: A healthy 20 year old male patient, with two previous admissions with atrial fibrillation, was admitted to the emergency room with paroxysmal atrial fibrillation. The patient presented evidence of cannabis abuse, and no other pathologic cause for atrial fibrillation. Sinus rhythm was restored and the patient was discharged. DISCUSSION: Cannabis abuse is responsible for a wide range of pathologies, including cognitive impairment, a rise in the prevalence of lung, head and neck tumors, atrial and ventricular arrhythmias, and an increase in the risk of ischemic cardiovascular events. CONCLUSIONS: Cannabis abuse can induce atrial fibrillation in predisposed patients. Good practice may consider the inclusion of cannabis abuse tests in young patients admitted due to atrial fibrillation, and definite medical advice to stop the drug abuse.

Comparison of Rhabdomyolysis Markers in Patients Undergoing Bariatric Surgery with Propofol and Inhalation-based Anesthesia.

BACKGROUND: Rhabdomyolysis is a relatively uncommon, severe complication of anesthesia and surgery in the morbidly obese. As the use of propofol-based anesthesia has been associated with an increased risk of rhabdomyolysis and metabolic acidosis, this pilot study was designed to assess the effect of propofol anesthesia on the incidence of rhabdomyolysis in morbidly obese patients undergoing bariatric surgery. METHODS: Thirty, morbidly obese patients (body mass index 43 ± 3 kg/m(2)) scheduled for bariatric laparoscopic sleeve gastrectomy were randomized to receive either propofol (P) or inhalational anesthetic (I)-based balanced general anesthesia. A sample of venous blood gas analysis including pH, bicarbonate concentrations, and calculated base excess was taken at the end of the operation. Creatine phosphokinase (CPK), troponin I, blood urea nitrogen, and creatinine plasma concentrations were measured at the end of the surgery and again 24 h later. RESULTS: All patients enrolled to the study completed it without significant complications. CPK, troponin I, blood urea nitrogen, and creatinine plasma concentrations at the end of the operation and at 24 h, as well as the bicarbonate concentration and the base excess at the end of the operation were not significantly different between the two study groups. A statistically significant mild respiratory acidosis was noted in the inhalational anesthetic group (pH 7.30 ± 0.04 vs. 7.36 ± 0.02 in the propofol group) CONCLUSIONS: This small-size pilot study may suggest that propofol-based anesthesia is not related to increased incidence of rhabdomyolysis in morbidly obese patients undergoing short, uncomplicated bariatric surgery.

Verification of intravenous catheter placement by auscultation--a simple, noninvasive technique.

BACKGROUND: Verification of proper placement of an intravenous catheter may not always be simple. We evaluated the auscultation technique for this purpose. METHODS: Twenty healthy volunteers were randomized for 18G catheter inserted intravenously either in the right (12) or left arm (8), and subcutaneously in the opposite arm. A standard stethoscope was placed over an area approximately 3 cm proximal to the tip of the catheter in the presumed direction of the vein to grade on a 0-6 scale the murmur heard by rapidly injecting 2 mL of NaCl 0.9% solution. The auscultation was evaluated by a blinded staff anesthesiologist. RESULTS: All 20 intravenous injection were evaluated as flow murmurs, and were graded an average 5.65 (±0.98), whereas all 20 subcutaneous injections were evaluated as either crackles or no sound, and were graded an average 2.00 (±1.38), without negative results. Sensitivity was calculated as 95%. Specificity and Kappa could not be calculated due to an empty false-positive group. CONCLUSIONS: Being simple, handy and noninvasive, we recommend to use the auscultation technique for verification of the proper placement of an intravenous catheter when uncertain of its position. Data obtained in our limited sample of healthy subjects need to be confirmed in the clinical setting.

Prolonged nerve blockade in a patient treated with lithium.

We report a case of a patient, chronically treated with oral lithium, who presented with an extremely prolonged (42-hour) duration of sensory and motor paralysis following an uneventful infraclavicular block for hand surgery that was performed under ultrasound guidance using bupivacaine and lidocaine. Due to its direct effect on nerve conduction of action potential, we propose that lithium may have had a role in the unusually prolonged duration of a peripheral nerve block.