Adoption of low tidal volume ventilation in the emergency department: A quality improvement intervention.

BACKGROUND: Ventilator tidal volumes of >8 mL/kg of predicted body weight (PBW) may increase the risk of lung injury. We sought to evaluate the impact of a quality improvement intervention among intubated Emergency Department (ED) patients to protocolize the prescription of low tidal volume ventilation. METHODS: In this before-and-after study, the average tidal volume delivered to ED patients receiving volume assist-control ventilation was compared before (2007-2014) and after (2015-2016) implementation of a ventilator initiation protocol (the quality improvement intervention). The intervention emphasized 1) measurement of the patient's height to calculate PBW and therefore tailor the tidal volume to estimated lung size (<8 mL/kg PBW), and 2) focused education and reference materials for ED physicians and respiratory therapists. RESULTS: Among ventilated ED patients meeting inclusion criteria in the before (N = 2185) and after (N = 774) cohorts, the mean (±SD) tidal volume decreased from 9.0 ±â€¯1.4 mL/kg to 7.2 ±â€¯0.9 mL/kg PBW following the intervention (absolute difference 1.8 mL/kg, 95% confidence interval 1.7 to 1.9 mL/kg, p < 0.001). The proportion of patients receiving low tidal volume ventilation increased after the intervention (72%), as compared to before (23%). Low tidal volume ventilation continued to be utilized at 24 h after ICU admission in patients who remained intubated in the cohort following the intervention (mean tidal volume 7.3 mL/kg PBW). CONCLUSIONS: Pairing a ventilator initiation protocol with focused education and resources for emergency physicians and respiratory therapists was associated with a significant reduction in tidal volume delivered to ED patients.

A Prospective Observational Study of Patients Receiving Intravenous and Intramuscular Olanzapine in the Emergency Department.

STUDY OBJECTIVE: Parenteral olanzapine is an emerging therapy for a variety of conditions in the emergency department (ED). Intramuscular administration is standard; however, intravenous administration has been proposed as a safe alternative route. We investigate the safety and efficacy of both intramuscular and intravenous olanzapine in the ED when used for a variety of indications. METHODS: This was a prospective observational study of patients presenting to an urban Level I trauma center ED. Trained research associates screened the ED for patients receiving parenteral olanzapine. The primary outcome of the study was incidence of respiratory depression measured with standard markers. Secondary outcomes included use of additional doses or sedatives, corrected QT interval (QTc) data, time to nadir sedation, adverse events, and physician assessment of efficacy. RESULTS: There were 784 patients included in the final analysis. Intravenous olanzapine was administered to 295 patients; 489 received intramuscular olanzapine. Respiratory depression occurred in 11 of 295 patients (3.7%; 95% confidence interval [CI] 1.6% to 5.9%) receiving intravenous olanzapine and 10 of 489 (2.0%; 95% CI 0.8% to 3.3%) receiving intramuscular olanzapine. Seven patients required intubation, 2 in the intravenous group and 5 in the intramuscular group. Nonrespiratory complications occurred in 8 patients, 6 of 295 (2.0%; 95% CI 0.4% to 3.6%) in the intravenous group and 2 of 489 (0.4%; 95% CI 0% to 0.96%) in the intramuscular group. Dysrhythmias were isolated to 2 episodes of bradycardia requiring only supportive care. CONCLUSION: These data suggest that, with proper monitoring, administration of olanzapine, both intramuscular and intravenous, is safe for several indications in the ED.

Impact of an Institutional Clinical Pathway on Emergency Physicians' Stated Preferences in Treating Patients with Low-Risk Pulmonary Embolism.

BACKGROUND: Evidence continues to accumulate that select patients with acute low-risk pulmonary embolism (PE) can be safely discharged from the emergency department. Despite this, outpatient management continues to be uncommon. We report changes in emergency providers' stated preferences on low-risk acute PE management before and after the development and implementation of an institutional clinical pathway and decision tool. METHODS: We performed an observational analysis of attending emergency physicians' stated preferences towards the management of low-risk acute PE using survey results before and after the development and implementation of an electronic health record-embedded institutional low-risk acute PE pathway. RESULTS: Attending emergency medicine providers reported feeling more comfortable using PE risk stratification scores to identify dischargeable low-risk PE patients and also reported that they would be more likely to discharge a hypothetical patient with low-risk acute PE. CONCLUSION: Our results suggest that the implementation of an institutional clinical pathway with integration into the electronic health record was associated with a change in emergency physicians' stated preferences for managing patients with acute low-risk PE in the emergency department. Implementation of an evidence-based standard pathway was associated with increased comfort and familiarity with PE risk stratification, and an increased comfort with and preference for early outpatient management of low-risk PE.

Using Near Infrared Spectroscopy for Tissue Oxygenation Monitoring During Procedural Sedation: The Occurrence of Peripheral Tissue Oxygenation Changes With Respiratory Depression and Supportive Airway Measures.

OBJECTIVES: The objective was to assess whether respiratory depression and supportive airway measures occurring during procedural sedation are associated with changes in peripheral tissue oxygen saturation (StO2 ). METHODS: This was a prospective observational study of adult patients undergoing procedural sedation in the emergency department (ED). Patients undergoing sedation with propofol, 1:1 propofol and ketamine, and 4:1 propofol and ketamine were included. Clinical interventions, sedative medication doses, vital signs, end-tidal capnography (ETCO2 ), pulse oximetry (SpO2 ), and peripheral tissue oxygen saturation (StO2 ) were recorded. Respiratory depression was defined as the occurrence of a recorded SpO2  < 92%, an increase in ETCO2  > 10 mm Hg from baseline, or loss of capnography waveform. Supportive airway measures documented during the procedure included bag-valve mask ventilation, airway repositioning maneuvers, increase in supplemental oxygen, and stimulation to induce respiration. Relative changes in StO2 between baseline and nadir were compared among patients who met respiratory depression criteria or required a supportive airway measure and those who did not. RESULTS: Ninety-three patients were enrolled. Thirty-two patients (34.4%) met criteria for respiratory depression, and 31 (33.3%) required intervention in the form of a supportive airway measure. The median percent change in StO2 from procedure baseline to nadir in patients meeting criteria for respiratory depression was 13.6%, compared to 4.2% in those who did not. The change in StO2 in patients who required a supportive airway measure was 12.5% versus 5.4% in those who did not. CONCLUSIONS: Patients with respiratory depression and the use of supportive airway measures had greater changes in StO2 during procedural sedation than in patients who did not. Peripheral tissue oxygen saturation monitoring may be a useful tool for assessing respiratory adverse events in patients undergoing procedural sedation in the ED.

A prospective study of ketamine versus haloperidol for severe prehospital agitation.

CONTEXT: Ketamine is an emerging drug for the treatment of acute undifferentiated agitation in the prehospital environment, however no prospective comparative studies have evaluated its effectiveness or safety in this clinical setting. OBJECTIVE: We hypothesized 5 mg/kg of intramuscular ketamine would be superior to 10 mg of intramuscular haloperidol for severe prehospital agitation, with time to adequate sedation as the primary outcome measure. METHODS: This was a prospective open label study of all patients in an urban EMS system requiring chemical sedation for severe acute undifferentiated agitation that were subsequently transported to the EMS system's primary Emergency Department. All paramedics were trained in the Altered Mental Status Scale and prospectively recorded agitation scores on all patients. Two 6-month periods where either ketamine or haloperidol was the first-line therapy for severe agitation were prospectively compared primarily for time to adequate sedation. Secondary outcomes included laboratory data and adverse medication events. RESULTS: 146 subjects were enrolled; 64 received ketamine, 82 received haloperidol. Median time to adequate sedation for the ketamine group was 5 minutes (range 0.4-23) vs. 17 minutes (range 2-84) in the haloperidol group (difference 12 minutes, 95% CI 9-15). Complications occurred in 49% (27/55) of patients receiving ketamine vs. 5% (4/82) in the haloperidol group. Complications specific to the ketamine group included hypersalivation (21/56, 38%), emergence reaction (5/52, 10%), vomiting (5/57, 9%), and laryngospasm (3/55, 5%). Intubation was also significantly higher in the ketamine group; 39% of patients receiving ketamine were intubated vs. 4% of patients receiving haloperidol. CONCLUSIONS: Ketamine is superior to haloperidol in terms of time to adequate sedation for severe prehospital acute undifferentiated agitation, but is associated with more complications and a higher intubation rate.

Stimulus-specific adaptation in specialized neurons in the inferior colliculus of the big brown bat, Eptesicus fuscus.

The inferior colliculus (IC) of the big brown bat (Eptesicus fuscus) contains specialized neurons that respond exclusively to highly specific spectrotemporal patterns such as sinusoidally frequency modulated (SFM) signals or directional frequency modulated sweeps (FM). Other specialized cells with I-shaped frequency response areas (FRAs) are tuned to very narrow frequency bands (1-2 kHz) in an amplitude-tolerant manner. In contrast, non-specialized neurons respond to any stimulus with energy in their frequency response area. IC neurons in several mammalian species, including bats, demonstrate stimulus-specific adaptation (SSA), a reduction in response to a high-probability stimulus. To evaluate the relation between stimulus selectivity and SSA, we presented sounds using an oddball stimulus paradigm and recorded extracellular responses of IC neurons. SFM-selective cells (n = 10), FM-selective cells (n = 7), and cells with I-shaped FRAs (n = 13) did not show SSA under any of the conditions tested (NSSI = 0.009, 0.033, 0.020 respectively). However, non-specialized neurons (n = 52) exhibited various levels of SSA (NSSI = 0.163), with a subset of these cells displaying strong adaptation. These findings suggest that SSA is not a ubiquitous characteristic of all neurons in the bat IC, but is present only in a subset of non-specialized neurons.