1-hour Observation Period Research Articles

Safety of mRNA vaccination for COVID‐19 in children with polyethylene glycol (PEG)‐asparaginase allergy

Safety of <scp>mRNA</scp> vaccination for <scp>COVID</scp>‐19 in children with polyethylene glycol (<scp>PEG</scp>)‐asparaginase allergy

Performance of low-cost GNSS equipment in monitoring of horizontal displacements

To investigate theperformance of low-cost GNSS equipment in monitoring horizontal displacements ANN-MB-GNSS and A10 antenna were installed on Zeiss-BRT-006 reduktionstachymeter, which can move with mm sensitivity in the horizontal plane. Ten days of static data were recorded with U-Blox-ZED-F9P-02B-GNSS receiver and processed with CSRS-PPP online-service. Considering theobservation period(12,6,3,1h), nine horizontal displacement magnitude tests were performed.Inaddition, GNSS-PPPAR solution percentages, multipath and signal-to-noise ratio values were considered. The results reveal that 20mm displacement can be determined (6mmRMSE) using the PPP approach based on a 3-hour observation period with A10antenna and 30mm can be determined (15mmRMSE) with UBX antenna with a 6-hour observation.

REVISITING HYPERSENSITIVITY REACTIONS TO THE MRNA COVID-19 VACCINE: TOLERANCE AFTER PREVIOUS HISTORY OF ANAPHYLAXIS

<h3>Introduction</h3> Based on the current evolving knowledge regarding potential mechanisms of immediate reactions to the COVID-19 vaccine, we wanted to study the clinical tolerance of subsequent mRNA vaccination in patients with reported anaphylaxis to either the Moderna® mRNA-1273 or Pfizer-BioNTech® BNT162b2 vaccine. <h3>Methods</h3> We revaluated a subgroup of 6 patients that reported anaphylaxis to the first COVID-19 vaccine (5/6 – level 2 Brighton criteria classification and 1/6 level 4), as part of a large prospective COVID-19 Vaccine study (ARCOV). Among these, PEG skin test was positive for 2/6 patients. Patient had safely received their second dose using a desensitization protocol and were offered a booster dose of the Pfizer-BioNTech COVID-19 vaccine using a two-step blinded placebo-controlled challenge with a 1-hour observation period in a monitored setting. <h3>Results</h3> All 6 patients were females with a history of atopy and anaphylaxis to other agents. One patient was premedicated with prednisone and antihistamine. One patient refused, one tolerated a single dose challenge in the community, 3 tolerated a 2-step challenge and 2 presented mild isolated skin reactions (one patient despite the premedication). These reactions were hives and itchiness and were managed with oral antihistamines. One patient reacted to placebo with pruritis, sensation of throat closure, and dizziness but following reassurance safely completed the open challenge. <h3>Conclusion</h3> Our results underline the safety of the mRNA COVID-19 booster vaccine in a monitored setting for patients with a previous history of anaphylaxis. Large scale studies are required to better understand the underlying mechanisms of the COVID-19 vaccine reported reactions.

A hybrid spectrum opportunities extraction scheme for cognitive wireless communication

A realistic and credible model capable of forecasting spectrum occupancy patterns of primary users (PU) needs to be developed to improve the functioning of cognitive radio networks (CRNs) in terms of the spectrum decision process. This will result in more efficient utilization of spectrum resources and the creation of a cognitive radio network. The goal of this study is to design an adaptive spectrum extraction decision mechanism for CRNs to increase the efficiency of spectrum usage. This was accomplished by predicting channel vacancy durations (CVDs) which were generated from measured spectrum consumption data for reverse links of global system for mobile communication (GSM) 900/1800 bands using the long short-term memory (LSTM) approach. Subsequently, an analysis of spatial opportunities of co-existing primary and secondary users within the GSM network was carried out. The potential for secondary users’ communication in the vicinity of the primary user without violating the set carrier-to-interference ratio was equally evaluated. Finally, an algorithm for the spectrum extraction decision process by a secondary user (SU) was developed. The algorithm's performance was measured in terms of primary user interference probability and spectrum utilization increase. MATLAB2018b and EXCEL 2016 were used to do the simulation. The root mean-square error (RMSE) of the CVD prediction for GSM 900 RL and 1800 RL per 60-minute observation period was 2.964 and 2.791 minutes, respectively. The estimated spatial opportunities for primary and secondary systems range from 14.29% to 28.57% for defined areas and around 9% for random places. Thus, primary user interference probability (PUIP) decreased by more than four fold and spectrum utilization increased by up to 50%.

Mediator production and severity of aspirin-induced respiratory reactions: Impact of sampling site and body mass index

Patients with aspirin-exacerbated respiratory disease can experience severe reactions during aspirin challenge that are associated with high levels of mast cell mediators. The tissue source and clinical factors contributing to systemic mediator levels are unknown. We sought to determine the concordance between respiratory tract and systemic inflammatory mediator levels and identify clinical factors associated with these mediators. We performed an oral aspirin challenge in 30 subjects with aspirin-exacerbated respiratory disease. Respiratory symptoms and function, nasal mucosal fluid, blood, and urine were collected at baseline, at the onset of a respiratory reaction, and over a 3-hour observation period. Changes in nasal and systemic mediator levels were compared. Neither tryptase nor leukotriene E4 levels in nasal fluid correlated with serum tryptase or urinary leukotriene E4 levels at baseline or during reactions. We observed no association between the baseline or aspirin-induced change in nasal versus urinary leukotriene E4 and serum tryptase levels. Body mass index inversely correlated with baseline and aspirin-induced urinary leukotriene E4, prostaglandin D2 metabolite, and serum tryptase levels, as well as with aspirin-induced symptoms and respiratory function, but not with nasal mediators. The levels of nasal and systemic aspirin-induced mast cell products are discordant in aspirin-exacerbated respiratory disease. Systemically detected levels are likely derived from mast cells outside of the sinonasal cavity and do not accurately reflect upper respiratory tract production. Increased body mass index decreases systemic mast cell mediator production and reaction severity, supporting a contribution of metabolic regulation in aspirin-induced systemic reactions.

Abstract 11430: Etripamil Nasal Spray Reduces Heart Rate in Patients with Paroxysmal Supraventricular Tachycardia Prior to Conversion to Sinus Rhythm

Introduction: Etripamil (E) is a rapidly and short acting, nasally administered calcium channel blocker being developed to terminate AV nodal-dependent PSVT. The NODE-301 first in class, multicenter study, evaluated self-administration of E nasal spray 70 mg outside a healthcare environment for acute termination of PSVT. This post-hoc analysis addresses the effect of E on heart rate (HR) during PSVT prior to conversion to sinus rhythm (SR). Methods: In NODE-301, 156 subjects experienced a vagal-maneuver refractory, symptomatic episode of confirmed PSVT, 107 subjects self-administered E and 49 placebo (P) (2:1 randomization) during PSVT. Each PSVT was documented by an ambulatory cardiac monitoring system that was placed on the chest after symptoms began. Baseline (average of four values before drug administration), and every minute of HR data were captured from baseline until one minute before the PSVT was converted to SR. Adequate HR data were available for 150 subjects, 102 on E and 48 on P. Six subjects were not included in this analysis, 4 converted before one minute (3 E and 1 P) and 2 E subjects experienced an early defect of recording. Results: Baseline mean (±SE) HR were 179 (±2.8) and 174 (±4.0) bpm for E and P respectively. Mean change in HR from baseline was greater in the E group than P group ( p &lt;0.0001). This decrease appeared within the first minute (-5 bpm ±0.9), 3 min (-10 bpm ±1.2), 10 min (-16 bpm ±2.1), 30 min (-14 bpm ±3.4) and 40 min (-13 bpm ±2.9) after E administration. The notable decrease in the E group was sustained through the 60minute observation period. A statistically significant difference in HR was reached between E and P notably at 3 ( p &lt;0.03), 10 ( p &lt;0.0001), 30 ( p &lt;0.0002), and 40 min ( p &lt;0.004). Conclusion: Etripamil significantly decreases the HR in PSVT prior to conversion to SR and is sustained over the 60 min observation. This finding may provide clinical benefits to patients for self-management of PSVT.

Detection of Bleeding Complications After Renal Transplant Biopsy

OBJECTIVE. The purpose of this study was to analyze the timing of major bleeding complications after renal transplant biopsy in the context of a standardized 1-hour postprocedure observation protocol. MATERIALS AND METHODS. We retrospectively reviewed the electronic medical records for consecutive patients who underwent ultrasound-guided renal transplant biopsies between January 1, 2012, and December 31, 2017, and were observed according to a newly implemented 1-hour postprocedure observation protocol. The development of a major bleeding complication (Common Terminology Criteria for Adverse Events class 3 or higher) was recorded along with all available details regarding the time course of patient symptoms and presentation. Complications were grouped into one of four categories according to onset time after biopsy: 2 hours or less (timing category 1), more than 2 hours but 4 hours or less (timing category 2), more than 4 hours but 8 hours or less (timing category 3), and more than 8 hours (timing category 4). RESULTS. In 1824 patients (769 women, 1055 men) who underwent 4519 consecutive ultrasound-guided renal transplant biopsies during the study period, 11 class 3 complications were found (11/4519 [0.2%]). Four of the 11 patients (36.4%) had symptoms during the 1-hour observation period. Of these four patients, three (3/11 [27.3%]) had substantial symptoms related to major bleeding and were classified as timing category 1, and one (1/11 [9.1%]) had initially minor symptoms that increased in severity more than 2 hours but within 4 hours and was classified as timing category 2. Seven of the 11 patients (63.6%) did not have any symptoms at 1 hour of observation and were discharged; three (27.3%) were classified as timing category 3, and four (36.4%) were classified as category 4. CONCLUSION. Major bleeding complications following ultrasound-guided renal transplant biopsy are rare (0.2% of patients in this study). In our study, more than half were not clinically apparent within 4 hours of biopsy. A 1-hour postprocedure recovery period can be safely used after renal transplant biopsy.

Respiratory viruses in the patient environment.

To characterize the presence and magnitude of viruses in the air and on surfaces in the rooms of hospitalized patients with respiratory viral infections, and to explore the association between care activities and viral contamination. Prospective observational study. Acute-care academic hospital. In total, 52 adult patients with a positive respiratory viral infection test within 3 days of observation participated. Healthcare workers (HCWs) were recruited in staff meetings and at the time of patient care, and 23 wore personal air-sampling devices. Viruses were measured in the air at a fixed location and in the personal breathing zone of HCWs. Predetermined environmental surfaces were sampled using premoistened Copan swabs at the beginning and at the end of the 3-hour observation period. Preamplification and quantitative real-time PCR methods were used to quantify viral pathogens. Overall, 43% of stationary and 22% of personal air samples were positive for virus. Positive stationary air samples were associated with ≥5 HCW encounters during the observation period (odds ratio [OR], 5.3; 95% confidence interval [CI], 1.2-37.8). Viruses were frequently detected on all of the surfaces sampled. Virus concentrations on the IV pole hanger and telephone were positively correlated with the number of contacts made by HCWs on those surfaces. The distributions of influenza, rhinoviruses, and other viruses in the environment were similar. Healthcare workers are at risk of contracting respiratory virus infections when delivering routine care for patients infected with the viruses, and they are at risk of disseminating virus because they touch virus-contaminated fomites.

Prospective Evaluation of Safe Observation Period after Asymptomatic Penetrating Thoracic Injury: 1 Hour is Enough.

Introduction:The observation period was recently challenged by some studies; and it has been suggested that a 1-hour observation period may be sufficient to allow safe discharge in asymptomatic patients with penetrating thoracic injury (PTI) and normal initial Chest X-Ray (CXR).Objective:The current study was performed to investigate if in asymptomatic and hemodynamically stable patients with PTIs who has an initial normal evaluation, 1-hour observation interval is safe to detect clinically significant injuries and is it possible to discharge these patients safely after a negative Extended – Focused Assessment with Sonography in Trauma (E-FAST) at hour1 instead of hour 3.Method:This cross-sectional study was performed on asymptomatic patients with penetrating thoracic injury, referred to emergency department (ED) and normal initial CXR and the Extended Focused Assessment with Sonography in Trauma (E-FAST). The second E-FAST was done 1 hour after the first one and the third repeat E-FAST and control CXR then performed 3 hours post-injury. 24 hours follow up by phone call was done for each patient after discharge.Results:Finally, 117 patients with the average ages of 25.9 ± 7.8 years were enrolled of whom 92.5% were male. Eight patients developed PTX or HTX during first hour of observation that were diagnosed by E-FAST or CT scan requested by the in-charge physician. One hundred-nine patient completed E-FAST and radiograph studies at times zero, 1 h, and 3 h. One patient had a normal initial evaluation but demonstrated a PTX on the 3-h managed without intervention. The rate of delayed abnormality after an initially normal study was 7.7 % (9/117). No discharged patients returned to our ED with delayed manifestations of either PTX or HTX.Conclusion:The results of our study have shown that asymptomatic patients with PTI with negative initial evaluation and no deterioration at intervals, about 1 hour may be sufficient for detection of clinically significant pathology, considered for safe and early discharge.

Hospital Observation Upon Reversal (HOUR) With Naloxone: A Prospective Clinical Prediction Rule Validation Study.

St. Paul's Early Discharge Rule was derived to determine which patients could be safely discharged from the emergency department after a 1-hour observation period following naloxone administration for opiate overdose. The rule suggested that patients could be safely discharged if they could mobilize as usual and had a normal oxygen saturation, respiratory rate, temperature, heart rate, and Glasgow Coma Scale score. Validation of the St. Paul's Early Discharge Rule is necessary to ensure that these criteria are appropriate to apply to patients presenting after an unintentional presumed opioid overdose in the context of emerging synthetic opioids and expanded naloxone access. In this prospective, observational validation study, emergency medicine providers assessed patients 1hour after administration of prehospital naloxone. Unlike in the derivation study the threshold for normal oxygen saturation was set at 95% and patients were not immediately discharged after a normal 1-hour evaluation. Patients were judged to have a normal 1-hour evaluation if all six criteria of the rule were met. Patients were judged to have an adverse event (AE) if they had one or more of the preestablished AEs. A total of 538 patients received at least one administration of prehospital naloxone, were transported to the study hospital, and had a 1-hour evaluation performed by a provider. AEs occurred in 82 (15.4%) patients. The rule exhibited a sensitivity of 84.1% (95% confidence interval [CI]= 76.2%-92.1%), a specificity of 62.1% (95% CI= 57.6%-66.5%), and a negative predictive value of 95.6% (95% CI= 93.3%-97.9%). Only one patient with a normal 1-hour evaluation subsequently received additional naloxone following a presumed heroin overdose. This rule may be used to risk stratify patients for early discharge following naloxone administration for suspected opioid overdose.

Physical compatibility of plazomicin with select i.v. drugs during simulated Y-site administration.

The results of a study to determine the physical compatibility of plazomicin sulfate solution during simulated Y-site administration with 92 i.v. drugs are reported. Plazomicin injection solution (500 mg/10 mL) was diluted in 0.9% sodium chloride or 5% dextrose for injection to a final volume of 50 mL (final plazomicin concentration, 24 mg/mL), consistent with a 15-mg/kg dose administered to an 80-kg patient (i.e., 1,200 mg). All other i.v. drugs were reconstituted according to manufacturers' recommendations and diluted with 0.9% sodium chloride or 5% dextrose for injection to the upper range of concentrations used clinically. Y-site conditions were simulated by mixing 5 mL of plazomicin solution with 5 mL of tested drug solutions in a 1:1 ratio. Solutions were assessed for visual (via color and Tyndall beam testing), turbidity (using a laboratory-grade turbidimeter), and pH changes over a 60-minute observation period. Incompatibility was defined a priori as precipitation, color change, a positive Tyndall test, or a turbidity change of ≥0.5 nephelometric turbidity units at any time during the 60-minute observation period. Plazomicin was physically compatible with 79 of the 92 drugs tested. Determinations of physical incompatibility with plazomicin were made for 13 drugs: albumin, amiodarone, amphotericin B deoxycholate, anidulafungin, calcium chloride, daptomycin, esomeprazole, heparin, levofloxacin, methylprednisolone, micafungin, phenytoin, and propofol, CONCLUSION: Plazomicin at a concentration of 24 mg/mL was physically compatible with 85% of the drugs tested, including 31 of 36 antimicrobial agents.

The Use of the Abdominal Aortic and Junctional Tourniquet During Cardiopulmonary Resuscitation Following Traumatic Cardiac Arrest in Swine.

Standard cardiopulmonary resuscitation (CPR) is ineffective in treating traumatic cardiac arrest (TCA) following hemorrhagic shock despite fluid resuscitation. CPR adjuncts, including abdominal compressions and external counter pressure, have shown some success in laboratory settings. The Abdominal Aortic and Junctional Tourniquet (AAJT) is a device that occludes both venous and arterial blood at the level of the aortic bifurcation and likely increases thoracic pressure when applied to the abdomen. We developed a swine model of controlled hemorrhage to induce a state of TCA to test the ability of the AAJT to improve the efficacy of CPR. Twelve splenectomized, Yorkshire, male swine (70-90 kg) were randomized into two groups: presence or absence of AAJT placement. Controlled hemorrhage was performed at a rate of 2 mL/kg/min until systolic blood pressure reached below 10 mm Hg (defined as cardiac arrest). Following 3 minutes of arrest, the animals underwent CPR using a mechanical compression device along with either the presence or absence of the AAJT. Concurrently, 5 units of whole blood (2,500 mL) were delivered through the jugular vein at 500 mL/min. Efficacy of CPR was assessed by analyzing rates of return of spontaneous circulation (ROSC) and survival. Blood pressure, carotid blood flow, and other hemodynamic values were also compared. No significant differences between groups were observed before treatments. The controlled hemorrhage resulted in an average loss of 2,654 ± 323 g of blood over 18.2 ± 3.9 minutes. All animals that had a ROSC survived to the end of the 1-hour observation period. Animals with AAJT survived 83% (5/6) compared to 17% (1/6) of animals without AAJT. Finally, blood pressure, carotid flow, mean pulmonary artery pressure, and end tidal carbon dioxide were all significantly different between groups at the end of the first 10-minute compression period. These results suggest that the AAJT could allow for increased CPR efficacy in cases of TCA when used in conjunction with rapid, massive blood transfusions.

NADH fluorescence imaging and the histological impact of cortical spreading depolarization during the acute phase of subarachnoid hemorrhage in rats.

OBJECTIVE Although cortical spreading depolarization (CSD) has been observed during the early phase of subarachnoid hemorrhage (SAH) in clinical settings, the pathogenicity of CSD is unclear. The aim of this study is to elucidate the effects of loss of membrane potential on neuronal damage during the acute phase of SAH. METHODS Twenty-four rats were subjected to SAH by the perforation method. The propagation of depolarization in the brain cortex was examined by using electrodes to monitor 2 direct-current (DC) potentials and obtaining NADH (reduced nicotinamide adenine dinucleotide) fluorescence images while exposing the parietal-temporal cortex to ultraviolet light. Cerebral blood flow (CBF) was monitored in the vicinity of the lateral electrode. Twenty-four hours after onset of SAH, histological damage was evaluated at the DC potential recording sites. RESULTS Changes in DC potentials (n = 48 in total) were sorted into 3 types according to the appearance of ischemic depolarization in the entire hemisphere following induction of SAH. In Type 1 changes (n = 21), ischemic depolarization was not observed during a 1-hour observation period. In Type 2 changes (n = 13), the DC potential demonstrated ischemic depolarization on initiation of SAH and recovered 80% from the maximal DC deflection during a 1-hour observation period (33.3 ± 15.8 minutes). In Type 3 changes (n = 14), the DC potential displayed ischemic depolarization and did not recover during a 1-hour observation period. Histological evaluations at DC potential recording sites showed intact tissue at all sites in the Type 1 group, whereas in the Type 2 and Type 3 groups neuronal damage of varying severity was observed depending on the duration of ischemic depolarization. The duration of depolarization that causes injury to 50% of neurons (P50) was estimated to be 22.4 minutes (95% confidence intervals 17.0-30.3 minutes). CSD was observed in 3 rats at 6 sites in the Type 1 group 5.1 ± 2.2 minutes after initiation of SAH. On NADH fluorescence images CSD was initially observed in the anterior cortex; it propagated through the entire hemisphere in the direction of the occipital cortex at a rate of 3 mm/minute, with repolarization in 2.3 ± 1.2 minutes. DC potential recording sites that had undergone CSD were found to have intact tissue 24 hours later. Compared with depolarization that caused 50% neuronal damage, the duration of CSD was too short to cause histological damage. CONCLUSIONS CSD was successfully visualized using NADH fluorescence. It propagated from the anterior to the posterior cortex along with an increase in CBF. The duration of depolarization in CSD (2.3 ± 1.2 minutes) was far shorter than that causing 50% neuronal damage (22.4 minutes) and was not associated with histological damage in the current experimental setting.

Clinical outcomes with olanzapine long-acting injection: impact of the 3-hour observation period on patient satisfaction and well-being

BackgroundThe objective of the present analysis is to determine the impact of the 3-hour observation period for olanzapine long-acting injection (LAI) on patient satisfaction and well-being by comparing data collected before and after its implementation.MethodsThis is a post hoc analysis of patients treated with olanzapine LAI in 1) a 6-month fixed-dose randomized controlled trial and/or 2) a 6-year open-label safety study. This analysis was limited to patients with schizophrenia who were treated with olanzapine LAI consistent with the approved indication and dosing recommendations of the European Union Summary of Product Characteristics (N=966). Of the 966 patients, the analysis further focused only on those patients who received both 1) at least one injection before the implementation of the 3-hour observation period and 2) at least one injection after implementation of the 3-hour observation period (N=487). Patient satisfaction was assessed with the three-item Patient Satisfaction with Medication Questionnaire-Modified. Responses were averaged across all postbaseline visits occurring before (ie, without) the implementation of the 3-hour observation period and across all postbaseline visits occurring after (ie, with) the implementation of the 3-hour observation period. In addition, the rate of postinjection delirium/sedation syndrome events was calculated.ResultsThere was no meaningful change after implementation of the 3-hour observation period in satisfaction (before: mean [SD] =4.0 [1.02] and after: mean [SD] =4.1 [0.82]), preference for olanzapine LAI over oral medication (before: mean [SD] =4.0 [0.90] and after: mean [SD] =4.1 [0.77]), or ratings of satisfaction regarding side effects (before: mean [SD] =1.9 [0.79] and after: mean [SD] =1.8 [0.60]). For the total population (N=966), postinjection delirium/sedation syndrome occurred in 26 (0.07%) of 38,010 injections.ConclusionFor patients with schizophrenia receiving treatment with olanzapine LAI, the 3-hour observation period had no impact on their satisfaction with the medication or on their subjective well-being.

A prospective, randomized trial of intravenous hydroxocobalamin versus whole blood transfusion compared to no treatment for Class III hemorrhagic shock resuscitation in a prehospital swine model.

The objective was to compare systolic blood pressure (sBP) over time in swine that have had 30% of their blood volume removed (Class III shock) and treated with intravenous (IV) whole blood or IV hydroxocobalamin, compared to nontreated control animals. Thirty swine (45 to 55 kg) were anesthetized, intubated, and instrumented with continuous femoral and pulmonary artery pressure monitoring. Animals were hemorrhaged a total of 20 mL/kg over a 20-minute period. Five minutes after hemorrhage, animals were randomly assigned to receive 150 mg/kg IV hydroxocobalamin solubilized in 180 mL of saline, 500 mL of whole blood, or no treatment. Animals were monitored for 60 minutes thereafter. A sample size of 10 animals per group was determined based on a power of 80% and an alpha of 0.05 to detect an effect size of at least a 0.25 difference (>1 standard deviation) in mean sBP between groups. sBP values were analyzed using repeated-measures analysis of variance (RANOVA). Secondary outcome data were analyzed using repeated-measures multivariate analysis of variance (RMANOVA). There were no significant differences between hemodynamic parameters of IV hydroxocobalamin versus whole blood versus control group at baseline (MANOVA; Wilks' lambda; p = 0.868) or immediately posthemorrhage (mean sBP = 47 mm Hg vs. 41 mm Hg vs. 37 mm Hg; mean arterial pressure = 39 mm Hg vs. 28 mm Hg vs. 34 mm Hg; mean serum lactate = 1.2 mmol/L vs. 1.4 mmol/L vs. 1.4 mmol/L; MANOVA; Wilks' lambda; p = 0.348). The outcome RANOVA model detected a significant difference by time between groups (p < 0.001). Specifically, 10 minutes after treatment, treated animals showed a significant increase in mean sBP compared to nontreated animals (mean sBP = 76.3 mm Hg vs. 85.7 mm Hg vs. 51.1 mm Hg; p < 0.001). RMANOVA modeling of the secondary data detected a significant difference in mean arterial pressure, heart rate, and serum lactate (p < 0.001). Similar to sBP, 10 minutes after treatment, treated animals showed a significant increase in mean arterial pressure compared to nontreated animals (mean arterial pressure = 67.7 mm Hg vs. 61.4 mm Hg vs. 40.5 mm Hg). By 10 minutes, mean heart rate was significantly slower in treated animals compared to nontreated animals (mean heart rate = 97.3 beats/min vs. 95.2 beats/min vs. 129.5 beats/min; p < 0.05). Serum lactate, an early predictor of shock, continued to rise in the control group, whereas it did not in treated animals. Thirty minutes after treatment, serum lactate values of treated animals were significantly lower compared to nontreated animals (p < 0.05). This trend continued throughout the 60-minute observation period such that 60-minute values for lactate were 1.4 mmol/L versus 1.1 mmol/L versus 3.8 mmol/L. IV hydroxocobalamin produced a statistically significant increase in systemic vascular resistance compared to control, but not whole blood, with a concomitant decrease in cardiac output. Intravenous hydroxocobalamin was more effective than no treatment and as effective as whole blood transfusion, in reversing hypotension and inhibiting rises in serum lactate in this prehospital, controlled, Class III swine hemorrhage model.

Abstract T P224: A Canine Model of Acute Segmental Vertebral Artery Embolism

BACKGROUND: Limited availability of suitable animal model of cerebrovascular thrombosis has hampered the study of mechanical thrombectomy and clot retrieval therapies. To facilitate endovascular interventional evaluations, this study aims to develop an animal model of acute occlusion in canine vertebral artery (VA). We developed a technique for site-specific placement of a thrombus in canine model for the purpose of evaluating methods of mechanical thrombectomy and clot retrieval that allows visualization of dislocation or fragmentation of the thrombus during angiographic manipulation. METHODS: Angiography and embolization with a preformed thrombus was performed in 6 canines. Bilateral femoral artery puncture were performed. Under fluoroscopic guidance, an embolism protection device (EPD) was anchored to the middle segment of the left vertebral artery via the left femoral arterial sheath. A preformed radiopaque clot was injected through the guide catheter into the left VA, via contralateral femoral artery, proximal to the EPD. After 15 min of occlusion, the EPD was removed and persistent occlusion of the VA was documented angiographically. RESULTS: Angiography performed during the observation period confirmed persistence of VA occlusion in each case. Each VA was occluded angiographically and radiopaque clots were not found displaced during the 3-hour observation period. The setting allowed selective embolization of targeted vessels without thrombus fragmentation. Recanalization to the occluded artery was not observed in all of the arteries. Histologic evaluation revealed no intimal damage caused by the thrombus or contrast agent washout. CONCLUSION: We demonstrated, for the first time, a canine model of post circulation embolism induced by the autologous blood clot placement. This model can be rapidly formed, easily operated, and site controlled. This new technique may be beneficial for preclinical evaluation of thrombectomy devices in acute cerebrovascular stroke.

Monitoring Hand Hygiene via Human Observers: How Should We Be Sampling?

To explore how hand hygiene observer scheduling influences the number of events and unique individuals observed. We deployed a mobile sensor network to capture detailed movement data for 6 categories of healthcare workers over a 2-week period. University of Iowa Hospital and Clinic medical intensive care unit (ICU). We recorded 33,721 time-stamped healthcare worker entries to and exits from patient rooms and considered each entry or exit to be an opportunity for hand hygiene. Architectural drawings were used to derive 4 optimal line-of-sight placements for observers. We ran simulations for different observer movement schedules, all with a budget of 1 hour of total observation time. We considered observation times of 1-15, 15-30, 30, and 60 minutes per station. We stochastically generated healthcare worker hand hygiene compliance on the basis of all data and recorded the total unit compliance as it would be reported by each simulated observer. Considering a 60-minute total observation period, aggregate simulated observers captured 1.7% of the average total number of opportunities per day at best and 0.5% at worst. The 1-15-minute schedule captures, on average, 16% fewer events than does the 60-minute (ie, static) schedule, but it samples 17% more unique individuals. The 1-15-minute schedule also provides the best estimator of compliance for the duration of the shift, with a mean standard deviation of 17%, compared with 23% for the 60-minute schedule. Our results show that observations are sensitive to different observers' schedules and suggest the importance of using data-driven approaches to schedule hand hygiene audits.

Isobolographic Method and Invertebrate (Planarian) Model for Evaluating Combinations of Waterways Pollutants

Agricultural, pharmaceutical, and other biologically active substances are emptied or leach into waterways and groundwater, where they can dose-relatedly cause pharmacologic or toxic effects on the resident or dependent animal species. Standard methods can be used to evaluate the effects of individual substances, but evaluation of combinations of substances is more difficult. The mathematically rigorous method of isobolographic analysis was coupled with a simple in vivo invertebrate model. Planarians were selected because they are the lowest extant species with a centralized nervous system. Neostigmine bromide and monopotassium phosphate (KH2PO4) were selected as representative of two types of potential pollutants. Neostigmine bromide and KH2PO4 individually produced dose-related lethality over a 60-minute observation period with LD50 values of 122 and 70 mM, respectively. The LD50 value of a 1:1 combination of the two was significantly different (p < 0.05) from the isobolographic line of additivity. We used planarians as a representative fresh-water species and joint-action (‘isobolographic’) analysis to examine possible interaction between pollutants. In the demonstrative example reported here, there was a subadditive interaction between a 1:1 fixed-ratio combination of neostigmine bromide (as a representative acetylcholinesterase inhibitor used in pesticides) and potassium phosphate (used in fertilizers and detergents).

Oxymetazoline Superior to Cocaine and Lidocaine for Nosebleeds

Oxymetazoline Superior to Cocaine and Lidocaine for Nosebleeds

Comparison of 10 hemostatic dressings in a groin puncture model in swine

The use of mineral (clay) or biologic (chitosan) materials has improved the efficacy of dressings used in the bleeding control of noncompressible areas. A series of novel manufactured products already evaluated in a vascular transection model was further compared in a severe vascular puncture injury model. Ten hemostatic dressings were tested in anesthetized Yorkshire swine hemorrhaged for 45 seconds in a femoral arterial puncture model. Application of these dressings was followed by 5 minutes of compression (about 175 mm Hg), and at 15 minutes, 500 mL resuscitation fluid (Hextand) was infused during a 30-minute period. The animals were monitored for a 3-hour experimental observation period. Primary outcomes were incidence of bleeding after dressing application and animal survival. Blood loss was 18.8% +/- 5.2% estimated blood volume (EBV) after 45 seconds of free bleeding. Relative performance of dressings is characterized as groups of dressings that performed similarly. Recurrence of bleeding after application was observed with most dressings and was lower with Woundstat, Celox, X-Sponge, and ACS+ (35% +/- 49%) compared with FP-21, Hemcon, Chitoflex, and Bloodstop (79% +/- 43%; P < .01). Blood loss after treatment was 25.3% +/- 18.4% EBV for the top four dressings and 53.0% +/- 18.4% EBV for the bottom four (P < .05). Survival was higher for top four vs bottom four dressings (78% +/- 12% vs 25% +/- 0%, respectively; P < .01). Overall performance of these dressings according to survival, incidence of bleeding, and post-treatment blood loss, yielded similar ranking as with a previously tested transection injury model. The findings indicated that the efficacy of Woundstat, Celox, X-Sponge, and ACS+ were similar and superior in improving survival, hemostasis, and maintenance of mean arterial pressure in an actively bleeding wound caused in this severe vascular injury model.