Can EMS Providers Provide Appropriate Tidal Volumes in a Simulated Adult-sized Patient with a Pediatric-sized Bag-Valve-Mask?

Introduction: In the prehospital setting, Emergency Medical Services (EMS) professionals rely on providing positive pressure ventilation with a bag-valve-mask (BVM). Multiple emergency medicine and critical care studies have shown that lung-protective ventilation protocols reduce morbidity and mortality. Our primary objective was to determine if a group of EMS professionals could provide ventilations with a smaller BVM that would be sufficient to ventilate patients. Secondary objectives included 1) if the pediatric bag provided volumes similar to lung-protective ventilation in the hospital setting and 2) compare volumes provided to the patient depending on the type of airway (mask, King tube, and intubation). Methods: Using a patient simulator of a head and thorax that was able to record respiratory rate, tidal volume, peak pressure, and minute volume via a laptop computer, participants were asked to ventilate the simulator during six 1-minute ventilation tests. The first scenario was BVM ventilation with an oropharyngeal airway in place ventilating with both an adult- and pediatric-sized BVM, the second scenario had a supraglottic airway and both bags, and the third scenario had an endotracheal tube and both bags. Participants were enrolled in convenience manner while they were on-duty and the research staff was able to travel to their stations. Prior to enrolling, participants were not given any additional training on ventilation skills. Results: We enrolled 50 providers from a large, busy, urban fire-based EMS agency with 14.96 (SD = 9.92) mean years of experience. Only 1.5% of all breaths delivered with the pediatric BVM during the ventilation scenarios were below the recommended tidal volume. A greater percentage of breaths delivered in the recommended range occurred when the pediatric BVM was used (17.5% vs 5.1%, p < 0.001). Median volumes for each scenario were 570.5mL, 664.0mL, 663.0mL for the pediatric BMV and 796.0mL, 994.5mL, 981.5mL for the adult BVM. In all three categories of airway devices, the pediatric BVM provided lower median tidal volumes (p < 0.001). Conclusion: The study suggests that ventilating an adult patient is possible with a smaller, pediatric-sized BVM. The tidal volumes recorded with the pediatric BVM were more consistent with lung-protective ventilation volumes.     

What Is the Minimal Pacing Rate that Prevents Torsades de Pointes? Insights from Patients with Permanent Pacemakers

In the acquired long QT syndrome, torsades de pointes (TP) is invariably preceded by pauses or bradycardia. Thus, it has been proposed that out-of-hospital initiation of drugs that prolong repolarization should be safe in patients with permanent pacemakers. However, a minimal protective pacing rate has not been identified. The authors reviewed published reports of acquired TP in patients with permanent pacing. Those providing documentation of tachycardia onset and pacemaker programming were included in the analysis. Events occurring < or = 1 month after AV nodal ablation were excluded. Eighteen cases were identified (age 74 +/- 5; 10 women). QT prolonging drugs were present in 15 patients (quinidine 5, sotalol 3, disopyramide 3, amytriptiline, chloroquine, cisapride + haloperidol, and monopride + flecainide 1 each). Hypokalemia was present in eight patients. At the time of TP, the programmed lower rate was 63 +/- 13 beats/min. However, the effective pacing rate was lower (55 +/- 11 beats/min) due to invocation of pause-promoting features (hysteresis [4 patients]; + PVARP extension on PVC [1 patient]) or ventricular oversensing (2 patients). No patient developed TP with an effective pacing rate > 70 beats/min. TP is possible in the presence of a functional permanent pacemaker. Programmed lower rates < or = 70 beats/min are not protective. At programmed lower rates > 70 beats/min, TP may occur only when facilitated by programmable pause-promoting features or oversensing. It remains to be seen if rate smoothing algorithms can prevent TP when the baseline rate is programmed < or = 70 beats/min.     

Can Clinical Parameters Predict Fractures in Acute Pediatric Wrist Injuries?

OBJECTIVE: Fractures around the wrist are common in pediatric patients presenting to the emergency department (ED). This pilot study was aimed at identifying clinical variables that are most likely to be associated with a fracture. METHODS: This was a prospective blinded case series of patients 3-18 years of age presenting with an acute (<3 days) wrist injury, without obvious deformity. A team of five investigators blinded to the eventual radiographic findings evaluated patients. Physical examination variables included range of motion (ROM), site of maximal tenderness, and functional deficit. The latter was determined objectively, by recording any difference in grip strength between the injured and noninjured hands. Diagnostic radiographs were obtained for all patients. Univariate analysis using Wilks' log likelihood ratio test was performed to identify clinical variables associated with confirmed wrist fractures. Sample size was determined based on the ability to detect a difference of 15 degrees in the ROM variables, 20% point differences in grip strength, and 30% proportion differences in categorical variables using a power of 0.8 and a two-tailed of 0.05. RESULTS: The ROMs were not significantly different between the fracture (Fx) and nonfracture (NFx) group. There was significant change in the grip strength between the Fx and NFx groups (t = 3.3, p = 0.0019). Tenderness over the distal radius was also associated with a greater likelihood of a fracture (G(2) = 5.0, p = 0.02). Sensitivity of clinical prediction was found to be 79%, and specificity was 63%. The false-negative rate was 0.21 and the false-positive rate was 0.37, while the positive predictive value was found to be 0.68 and negative predictive value 0.75. CONCLUSIONS: Distal radius point tenderness and a 20% or more decrease in grip strength were predictive of fractures.     

Dose Optimization of Vancomycin Using a Mechanism-based Exposure–Response Model in Pediatric Infectious Disease Patients

PurposeThis study aimed to determine the appropriate vancomycin dosage, considering patient size and organ maturation, by simulating the bacterial count and biomarker level for drug administration in pediatric patients with gram-positive bacterial (GPB) infections.MethodsNatural language processing for n-gram analysis was used to detect appropriate pharmacodynamic (PD) markers in infectious disease patients. In addition, a mechanism-based model was established to describe the systemic exposure and evaluate the PD marker simultaneously in pediatric patients. A simulation study was then conducted by using a mechanism-based model to evaluate the optimal dose of vancomycin in pediatric patients.Findings: C-reactive protein (CRP) was selected as a PD marker from an analysis of ~270,000 abstracts in PubMed. In addition, clinical results, including the vancomycin plasma concentrations and CRP levels of pediatric patients (n = 93), were collected from electronic medical records. The vancomycin pharmacokinetic model with allometric scaling and a maturation function was built as a one-compartment model, with an additional compartment for bacteria. Both the effects of vancomycin plasma concentrations on the destruction of bacteria and those of bacteria on CRP production rates were represented by using a maximum achievable effect model (E_max model). Simulation for dose optimization was conducted not only by using the final model but also by exploring the possibility of therapeutic failure based on the MICs of vancomycin for GPB. Clinical cure was defined as when the CRP level fell below the upper limit of the normal range. Our dose optimization simulations suggested a vancomycin dosage of 10 mg/kg every 8 h as the optimal maintenance dose for pediatric patients with a postconceptual age <30 weeks and 10 mg/kg every 6 h for older children, aged up to 12 years. In addition, the MIC of 3 μg/mL was assessed as the upper concentration limit associated with successful vancomycin treatment of GPB infections.ImplicationsThis study confirmed that the changes in bacterial counts and CRP levels were well described with mechanistic exposure–response modeling of vancomycin. This model can be used to determine optimal empiric doses of vancomycin and to improve therapeutic outcomes in pediatric patients with GPB.     

Can Benign Etiologies Predict Benign Outcomes in High-Risk Syncope Patients?

Background: We previously studied and validated risk factors for adverse outcomes or need for critical intervention in syncope. Objective: To determine whether high-risk patients, diagnosed with benign etiologies of syncope after a normal emergency department (ED) work-up, sustain favorable outcomes. Methods: Prospective, observational cohort of consecutive ED patients aged ≥ 18 years with syncope. Benign etiology was defined as vasovagal syncope or dehydration. Patients were followed up to 30 days to identify adverse outcomes including death, myocardial infarction, dysrhythmia, alterations in antidysrhythmics, percutaneous intervention, pulmonary embolus, stroke, metabolic catastrophe, or significant hemorrhage. Results: Patients presented with benign etiologies in 164/293, 56% (95% confidence interval [CI] 50–62%) of cases. Of these, pathologic conditions were identified during ED evaluation in 11/164, 7% (95% CI 3–11%) of cases. This includes ED findings/treatments of blood transfusion, severe electrolyte disturbance, incarcerated hernia, rhabdomyolysis, subarachnoid hemorrhage, bowel obstruction, dysrhythmia, and transient ischemic attack. The remaining 153 with benign presentations had no adverse outcomes at 30 days, while 57/129 (44%) patients with non-benign etiologies had adverse outcomes in the hospital or within 30 days. Previously, we demonstrated a 48% reduction in admission rate if only patients with risk factors for adverse outcome were admitted. If patients with both benign etiologies and a negative ED work-up were sent home, even if they had risk factors for an adverse outcome, an additional 19% (95% CI 14–25%) reduction in hospital admissions would have occurred. Conclusions: In patients with presentations consistent with a benign etiology of syncope (vasovagal or dehydration) where the ED work-up was normal, we found no patients who would benefit from hospitalization based on risk factors alone.     

Psychiatric Patients: How Can We Decide if You Are in Pain?

How do psychiatric nurses make decisions about pain management for hospitalized psychiatric patients? This is the question addressed by this research. Using an exploratory, naturalistic interview approach, 20 nurses and managers in varied settings described their decision making when providing pain relief. Analysis of these narratives indicates that decision making about pain, in this unique context, is influenced by a number of intrapersonal and interpersonal factors such as the patients' needs, history, and diagnosis; nurses' beliefs about pain tolerance and drug addiction; collegial pressure; and unit safety. For example, diagnosis and patient history impact pain relief negatively, while the responsibility to maintain a safe environment imposes pressure to administer medication. Although, in a psychiatric unit, the nurse-patient relationship is essential to the healing process, nurses often face a dilemma as to whether the pain medication will contribute to healing or exacerbate the patient's issues. In psychiatric wards, the means of recovery are far less clear, tangible, and immediate than in other clinical settings. Recommendations are made for better preparing and supporting nurses to work effectively in these practice settings where pain relief is confounded by addiction and psychiatric diagnoses.     

Malpractice in Invasive Cardiology: Is Angiography of Abdominal Aorta or Subclavian Artery Appropriate in Patients Undergoing Coronary Angiography?

Background: Identification of peripheral vascular disease by angiography in patients undergoing coronary angiography may be considered as malpractice but sometimes seems to be justified under clear entry criteria. The present mata-analysis is aimed to analyze the appropriateness and results of screening angiography of subclavian or abdominal aorta performed at the time of coronary angiography. Methods: A search of published literature for peripheral angiography in patients undergoing coronary angiography over the last 10 years was performed using the MEDLINE database. No language restriction was employed. Only studies enrolling more than 100 patients for abdominal aortography and 50 patients for subclavian/internal mammary artery angiography were considered. Reference lists from identified studies were also reviewed to identify other potentially relevant references. Results: Twenty-nine studies were retrieved: 8 articles about subclavian artery (SA) and internal mammary (IMA) angiography and 21 about renal (RA) and aortoiliac (AOI) angiography. The total number of patients enrolled was 27,936. Nine studies out of 29 were prospective. Defined entry criteria were reported in 24 out of 29 studies. Significant SA and IMA stenosis were reported in 5.5 and 9% of patients, respectively. RA stenosis >50% was present in 12.7% of patients with CAD. Finally, undetected AOI disease was reported in 35.5% of patients undergoing coronary angiography. Mean complication rate was 0.8 ± 0.6%. Predictors of SA and IMA stenosis were unclear. Age, multi-risk profile, multi-vessel CAD, history of PVD or carotid disease, severe hypertension, unexplained renal dysfunction or decreased creatinine clearance have been reported most frequently as predictors of RA and AOI disease in patients undergoing coronary angiography. Conclusions: Consistent evidence of appropriateness of renal angiography in selected patients undergoing coronary angiography have been produced in literature. IMA and AOI angiography seem to be not justified unless they are part of SA in patients scheduled for arterial conduit with brachial differential pressure, thoracic irradiation or surgery, or of abdominal angiography to detect RA stenosis in laboratories with radiological digital peripheral equipment.     

Does RV Lead Positioning Provide Additional Benefit to Cardiac Resynchronization Therapy in Patients with Advanced Heart Failure?

BACKGROUND AND OBJECTIVES: The left ventricular (LV) stimulation site is currently recommended to position the lead at the lateral wall. However, little is known as to whether right ventricular (RV) lead positioning is also important for cardiac resynchronization therapy. This study compared the acute hemodynamic response to biventricular pacing (BiV) at two different RV stimulation sites: RV high septum (RVHS) and RV apex (RVA). METHODS AND RESULTS: Using micro-manometer-tipped catheter, LV pressure was measured during BiV pacing at RV (RVA or RVHS) and LV free wall in 33 patients. Changes in LV dP/dt(max) and dP/dt(min) from baseline were compared between RVA and RVHS. BiV pacing increased dP/dt(max) by 30.3 +/- 1.2% in RVHS and by 33.3 +/- 1.7% in RVA (P = n.s.), and decreased dP/dt(min) by 11.4 +/- 0.7% in RVHS and by 13.0 +/- 1.0% in RVA (P = n.s.). To explore the optimal combination of RV and LV stimulation sites, we assessed separately the role of RV positioning with LV pacing at anterolateral (AL), lateral (LAT), or posterolateral (PL) segment. When the LV was paced at AL or LAT, the increase in dP/dt(max) with RVHS pacing was smaller than that with RVA pacing (AL: 12.2 +/- 2.2% vs 19.3 +/- 2.1%, P < 0.05; LAT: 22.0 +/- 2.7% vs 28.5 +/- 2.2%, P < 0.05). There was no difference in dP/dt(min) between RVHS- and RVA pacing in individual LV segments. CONCLUSIONS: RVHS stimulation has no overall advantage as an alternative stimulation site for RVA during BiV pacing. RVHS was equivalent with RVA in combination with the PL LV site, while RVA was superior to RVHS in combination with AL or LAT LV site.