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Department of Emergency Medicine

Department of Emergency Medicine

2012 - March R3 Journal Review

Lim T, Ryu HG, Jung CW, Jeon Y, Bahk, JH.  Effect of the bevel direction of puncture needle on success rate and complications during internal jugular vein catheterization.  Crit Care Med.  2012 Feb;40(2):491-4. This prospective, randomized, controlled study compared the bevel-down against the bevel-up approach during right IJ venous catheterization to evaluate if bevel direction was associated with differences in complication rates, specifically in regards to hematoma formation.  Three hundred and thirty-eight patients who were scheduled for thoracic surgery and required central venous catheterization in the right IJV were enrolled.  Patients were randomized to either a bevel-down group or a bevel-up group.  Patients were excluded from the study if they had catheterization site inflammation, carotid artery disease, contralateral diaphragmatic dysfunction, thyroid hypertrophy, previous operation history of the neck or thorax, or previous catheterization history of the right IJ vein.  After induction of general anesthesia, an experienced anesthetist, who was blinded to the study protocol, used ultrasound to mark out the intended path along the long axis of the IJV along with the intended puncture point.  Next, a second-year anesthesia resident would insert the central venous catheter using a modified Seldinger technique, utilizing the markings on the skin as a guide.  Venous entry of the needle was determined by brisk return of free-flowing venous blood.  Blood return during advancing of the needle was regarded as “puncture-on-advance,” whereas blood return during withdrawal of the needle was regarded as “puncture-on-withdrawal.”  After IVJ catheterization, the same anesthesiologist who had performed the initial ultrasound markings for the puncture site, returned and used an ultrasound machine to evaluate for any local complications such as hematoma formation or vessel wall damage.  There were 169 patients in either group.  Patient characteristics were statistically insignificant between the two groups.  The authors found that there was a statistically significant difference in the incidence of posterior wall hematoma, with the bevel-down group having a lower incidence (3.6% [6 out of 169]) compared to the bevel-up group (10.1% [17 out of 169]) with a p value of 0.031.  The rates of puncture-on-withdrawal between the 2 groups were not statistically significant, but the incidence of posterior hematoma with a puncture-on-withdrawal was lower in the bevel-down group (16.2% [6 out of 37]) compared to the bevel-up group (44% [11 out of 25]) with a p value of 0.034.  The authors concluded that IVJ catheterization with the bevel-down was associated with fewer posterior wall hematomas.  However, a limitation to the study was that the IVJ catheterizations were not done under real-time ultrasound guidance, which may have had an effect on the complication rates.  Furthermore, the clinical effects of the posterior hematomas were not elaborated on, meaning that although the bevel-up group may have had a higher rate of posterior hematomas, these hematomas may be of no clinical importance.

- Charles Vu

Intramuscular versus Intravenous Therapy for Prehospital Status Epilepticus.”  Silbergleit, et al. NEJM. 366(7): 591-600. Intro:  Previous studies have shown that IV lorazepam and diazepam have similar efficacies when administered IV in the prehospital setting. Many EMS systems have started using IM midazolam as IM administration is faster and more reliable than IV. IV lorazepam is not used often due to the difficulty with IV administration, as well as the short shelf life of lorazepam when it is not refrigerated. This was a non-inferiority study that compared IM midazolam to IV lorazepam in the prehospital setting.  Methods: This was a randomized, double blind non-inferiority trial. The study was nationwide, involving 4314 paramedics, 33 EMS agencies, and 79 receiving hospitals. Eligible patients were adults and children with an estimated weight >13 kg.  Inclusion criteria were patient’s seizing >5 minutes, or multiple seizures without regaining consciousness for longer than 5 minutes. Exclusion criteria included trauma as precipitant, hypoglycemia, cardiac arrest, HR <40, known allergy to the meds, pregnant, or prisoner. Patients received wither 10 mg IM midazolam plus IV placebo, or IM placebo plus 4 mg IV lorazepam. Each kit contained one of those combinations, and was randomized. Patients received IM drug/placebo through an auto-injector first, and then an IV was established. They were also allowed to use IO if they could not get an IV after 10 minutes. Primary outcome was termination of seizure prior to arrival to ED. Secondary outcomes were time from opening of study kit to termination of seizure, time from administration of active drug to termination of seizure, frequency and duration of hospitalization and or admits to ICU, and frequency of intubation.  Results:  A total of 893 subjects were enrolled. Seizures were absent in 329/448 patients who received IM midazolam (73.4%) and 282/445 (63.4%), P<0.001 for non-inferiority and P<0.001 for superiority. The frequencies of endotracheal intubation, recurrent seizures, and IV/IM injection site complications were also similar between the 2 groups.  LOS in ICU and hospital did not differ significantly. Proportion of patients admitted was significantly lower in the IM midazolam group (P=0.01). They also noted that time to administration was shorter for IM midazolam, but onset of action was faster in IV lorazepam.  Limitations:  Not everyone in the IV group actually had an IV established. 31 never got the IV medication versus only 5 in the IM group didn’t receive medication.  They site that the IV lorazepam took longer to administer, which is most likely true, but in their time analysis, didn’t take into account that they were required to do the IM auto-injector first, which will obviously take some amount of time.  The use of the auto-injector is also a limitation, as not every EMS rig will have this set-up, so different set-ups will take differing amount of time and will like have different efficacies.  Discussion: This study shows that IM midazolam is non-inferior to IV lorazepam in the pre-hospital setting. It is quicker to administer and showed better resolution of seizure activity than IV lorazepam.  All-in-all seems to be a good study design, with reasonable outcomes, and only minor limitations.  This probably won’t change our practice too much, since this is pre-hospital, but we do occasionally get calls on radio for medication requests for seizures, so may be pertinent.

- Josh Radke