Video-stylet vs. channeled hyperangulated videolaryngoscope: Efficacy in simulated Ludwig's angina randomized cadaver trial.

INTRODUCTION: Ludwig's angina (LA) is a life-threatening infection that can affect the floor of the mouth and neck, potentially causing serious airway obstruction. In such cases, rescue airway management and oxygenation can be challenging due to swelling of the mouth floor, trismus, and limited mouth opening. The aim of this study was to assess the efficacy of the Trachway video-stylet (VS) and Pentax AWS hyperangulated videolaryngoscope with channel (HAVL-C) compared to the standard geometric video-laryngoscope (SGVL, Macintosh 3, Trachway) in simulating Ludwig's angina with cadavers. METHODS: Three fresh frozen cadavers were prepared with varying degrees of difficulty to simulate the airway conditions of patients with LA, including mouth floor swelling, restricted mouth opening, and trismus. Fifty-five second-year resident physicians from various specialties participated in the study and received training in airway management using SGVL, VS, and HAVL-C devices. Participants were randomly assigned to intubate simulated LA with cadavers using the three devices in a random order, and intubation times and success rates were recorded. Participants also rated the difficulty of intubation using a visual analogue scale (VAS) score. The primary outcome assessed the first-pass intubation success or failure, while the secondary outcomes measured the intubation time and subjective difficulty using a visual analogue scale with different laryngoscopes. RESULTS: The success rates for intubation within 90 s were 40% for SGVL, 82% for VS, and 76% for HAVL-C. VS and HAVL-C had significantly higher success rates than SGVL, with hazard ratios of 3.4 and 2.7, and 95% confidence intervals (CI) of 2.0-5.7 and 1.6-4.6, p < 0.001, respectively. The odds ratios of successful intubation for VS and HAVL-C were 8.1 and 6.3, respectively, with a 95% CI of 3.7-17.8 and 2.4-16.7, p < 0.001, compared to SGVL. The VAS score was significantly correlated with intubation success rate and time. CONCLUSIONS: In cases of LA, the use of VS and HAVL-C is preferable over SGVL. These findings suggest that using VS and HAVL-C can improve intubation success rates and reduce intubation time in patients with LA.

Continuous aerosol monitoring and comparison of aerosol exposure based on smoke dispersion distance and concentrations during oxygenation therapy.

This study evaluated the aerosol exposure risks while using common noninvasive oxygenation devices. A simulated mannequin was designed to breathe at a minute ventilation of 20 L/min and used the following oxygen-therapy devices: nasal cannula oxygenation (NCO) at 4 and 15 L/min, nonrebreathing mask (NRM) at 15 L/min, simple mask at 6 L/min, combination of NCO at 15 L/min and NRM at 15 L/min, high-flow nasal cannula (HFNC) at 50 L/min, and flush rate NRM. Two-dimension of the dispersion distance and the aerosol concentrations were measured at head, trunk, and foot around the mannequin for over 10 min. HFNC and flush-rate NRM yielded the longest dispersion distance and highest aerosol concentrations over the three sites of the mannequin than the other oxygenation devices and should use with caution. For flow rates of < 15 L/min, oxygenation devices with mask-like effects, such as NRM or NCO with NRM, decreased aerosol dispersion more effectively than NCO alone or a simple mask. In the upright position, the foot area exhibited the highest aerosol concentration regardless of the oxygenation device than the head-trunk areas of the mannequin. Healthcare workers should be alert even at the foot side of the patient while administering oxygenation therapy.

A comparative analysis of aerosol exposure and prevention strategies in bystander, pre-hospital, and inpatient cardiopulmonary resuscitation using simulation manikins.

To evaluate aerosol exposure risk and prevention strategies during bystander, pre-hospital, and inpatient cardiopulmonary resuscitation (CPR). This study compared hands-only CPR, CPR with a surgical or N95 mask, and CPR with a non-rebreather mask at 15 L/min. 30:2 compression-ventilation ratio CPR was tested with face-mask ventilation (FMV), FMV with a high efficiency particulate air (HEPA) filter; supraglottic airway (SGA), SGA with a surgical mask, SGA with a HEPA filter, or SGA with both. Continuous CPR was tested with an endotracheal tube (ET), ET with a surgical mask, a HEPA filter, or both. Aerosol concentration at the head, trunk, and feet of the mannequin were measured to evaluate exposure to CPR personnel. Hands-only CPR with a surgical or N95 face mask coverings and ET tube ventilation CPR with filters showed the lowest aerosol exposure among all study groups, including CPR with NRM oxygenation, FMV, and SGA ventilation. NRM had a mask effect and reduced aerosol exposure at the head, trunk, and feet of the mannequin. FMV with filters during 30:2 CPR reduced aerosol exposure at the head and trunk, but increased at the feet of the mannequin. A tightly-sealed SGA when used with a HEPA filter, reduced aerosol exposure by 21.00-63.14% compared with a loose-fitting one. Hands-only CPR with a proper fit surgical or N95 face mask coverings is as safe as ET tube ventilation CPR with filters, compared with CPR with NRM, FMV, and SGA. FMV or tight-sealed SGA ventilation with filters prolonged the duration to achieve estimated infective dose of SARS-CoV-2 2.4-2.5 times longer than hands-on CPR only. However, a loose-fitting SGA is not protective at all to chest compressor or health workers standing at the foot side of the victim, so should be used with caution even when using with HEPA filters.

The Aerosol-Generating Effect Among Noninvasive Positive Pressure Ventilation, High-Flow Nasal Cannula, Nonrebreather Mask, Nasal Cannula, and Ventilator-Assisted Preoxygenation.

STUDY OBJECTIVE: To evaluate aerosol dispersion and exposure risk during oxygenation therapy among health care personnel. METHODS: This study compared the aerosol dispersion effect produced through continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), BiPAP with face coverings, a high-flow nasal cannula (HFNC) with face coverings, nasal cannula oxygenation (NCO) at 15 L/min with face coverings, nonrebreather mask (NRM), and ventilator-assisted preoxygenation (VAPOX) during oxygenation therapy at a minute ventilation of 10 L/min and 20 L/min. The length and width of aerosol dispersion were recorded, and aerosol concentrations were then detected at a mannequin's head, trunk, and feet. RESULTS: The average length dispersion distance of CPAP was 47.12 cm (SD, 12.56 cm), of BiPAP was 100.13 cm (SD, 6.03 cm), of BiPAP with face coverings was 62.20 cm (SD, 8.46 cm), of HFNC with face coverings was 67.09 cm (SD, 12.74 cm); of NCO with face coverings was 85.55 cm (SD, 7.28 cm); and of NRM was 63.08 cm (SD, 15.33 cm); VAPOX showed no visible dispersion. The aerosol concentrations at the feet under CPAP and at the head under BiPAP were significantly higher than those observed without an oxygen device. Compared with no oxygen device, the aerosol concentration with HFNC was higher at the mannequin's head, trunk, and feet; whereas it was lower with VAPOX and NRM. Moreover, when translated to the number of virus particles required to infect medical personnel (Nf), VAPOX took more time to achieve Nf than other devices. CONCLUSION: Strong flow from the oxygenation devices resulted in increased aerosol concentrations. CPAP at the feet side, BiPAP at the head side, HFNC, and NCO with face coverings significantly increase aerosol exposure and should be used with caution. Aerosol concentrations at all positions were lower with NRM and VAPOX.

Comparing the effectiveness of negative-pressure barrier devices in providing air clearance to prevent aerosol transmission.

PURPOSE: To investigate the effectiveness of aerosol clearance using an aerosol box, aerosol bag, wall suction, and a high-efficiency particulate air (HEPA) filter evacuator to prevent aerosol transmission. METHODS: The flow field was visualized using three protective device settings (an aerosol box, and an aerosol bag with and without sealed working channels) and four suction settings (no suction, wall suction, and a HEPA filter evacuator at flow rates of 415 liters per minute [LPM] and 530 LPM). All 12 subgroups were compared with a no intervention group. The primary outcome, aerosol concentration, was measured at the head, trunk, and foot of a mannequin. RESULTS: The mean aerosol concentration was reduced at the head (p < 0.001) but increased at the feet (p = 0.005) with an aerosol box compared with no intervention. Non-sealed aerosol bags increased exposure at the head and trunk (both, p < 0.001). Sealed aerosol bags reduced aerosol concentration at the head, trunk, and foot of the mannequin (p < 0.001). A sealed aerosol bag alone, with wall suction, or with a HEPA filter evacuator reduced the aerosol concentration at the head by 7.15%, 36.61%, and 84.70%, respectively (99.9% confidence interval [CI]: -4.51-18.81, 27.48-45.73, and 78.99-90.40); trunk by 70.95%, 73.99%, and 91.59%, respectively (99.9% CI: 59.83-82.07, 52.64-95.33, and 87.51-95.66); and feet by 69.16%, 75.57%, and 92.30%, respectively (99.9% CI: 63.18-75.15, 69.76-81.37, and 88.18-96.42), compared with an aerosol box alone. CONCLUSIONS: As aerosols spread, an airtight container with sealed working channels is effective when combined with suction devices.

The evaluation of a better intubation strategy when only the epiglottis is visible: a randomized, cross-over mannequin study.

BACKGROUND: The Cormack-Lehane (C-L) grade III airway is considered to be a challenging airway to intubate and is associated with a poor intubation success rate. The purpose of this study was to investigate whether the holding position, shapes, bend angles of the endotracheal tube (ET) and the stylet-assisted lifting of the epiglottis could improve the success rate of intubation. METHODS: Thirty-two participants, 26 physicians, 2 residents, and 4 nurse practitioners, with 12.09 ± 5.38 years of work experience in the emergency department and more than 150 annual intubation events, were enrolled in this randomized, cross-over mannequin study. We investigated the effects of straight-to-cuff ET shapes with 35° and 50° bend angles, banana-shaped ET with longitudinal distances of 28 cm and 26 cm, two methods of holding the ET (either on the top or in the middle), and lifting or not the epiglottis, on the intubation duration, its success rate, and its subjective difficulty. The aim of the study is to provide optimized intubation strategies for difficult airway with C-L IIb or III grades, when the inlet of the trachea cannot be visualized. RESULTS: The two groups that lifted the epiglottis using the stylets, in bend angles of 35° and 50°, had the shortest duration of intubation (23.75 ± 14.24 s and 20.72 ± 6.90 s, hazard ratios 1.54 and 1.85 with 95% confidence intervals [95% CI] of 1.01-2.34 and 1.23-2.78, respectively) and a 100% success rate in intubations. In the survival analysis, lifting of the epiglottis was the only significant factor (p < 0.0001, 95% CI 1.34-2.11) associated with the success rate of intubation. CONCLUSIONS: The use of the epiglottic lift as an adjunctive technique can facilitate the intubation and improve its success rate without increasing procedure difficulty, in C-L III airway, when only the epiglottis is seen. TRIAL REGISTRATION: ClinicalTrials Registry ( https://clincaltrials.gov , identifier NCT03366311).

Review of Emergency Response Management of 33 Major Burn Victims of the Formosa Fun Coast Dust Explosion Disaster in a Regional Hospital Without Burn Units.

BACKGROUND: The Formosa Fun Coast Dust Explosion is one of the major national disasters in Taiwan. The Taipei City Hospital (TCH), a regional hospital without a burn unit, received 33 patients out of 499 casualties in the initial response period. This retrospective study aimed to review the primary response of TCH and the outcome and mortality of the patients who were initially managed at TCH. METHODS: Basic profi les, total body surface area (TBSA) with burn injury, facial burn injury, vital signs, laboratory data, intubation rate and clinical outcomes, such as urine output and mortality, were analyzed. Moreover, the emergency department (ED) response faculties, who were involved in the initial response, were interviewed about the critical decision-making processes during the patient surge in the ED. RESULTS: The average initial estimated TBSA with burn injury in ED was 34.2%, and the average final TBSA assessed in the intensive care unit was 41.0%. The patients with facial burn injury were 38.7%, and the intubation rate was 22.6%. When comparing the result of TCH to the patient group transferred directly to Chang Gung Memorial Hospital (CGMH), and the group received by CGMH from other hospital, the mortality rate was 0.0, 5.7, 9.1%; and the delayed intubation rate was 3.0, 14.3, 27.3%, respectively. The key elements for effi cient initial response were the multidisciplinary response team cooperated as a production line, using the clipboards for orders recordings, and the plastic surgeons ED-operating room (OR) direct transferring. CONCLUSIONS: Regarding airway complications, and mortality, patients who were initially managed in TCH had comparable results with patients directly sent to the burn centers. This study supports the notion that immediate resuscitation in multiple level of hospitals, even without burn units but with adequate recruited response personnel, provided the best chance for the survival of casualties during such national disasters.

An Evaluation of the Use of Student Response Systems in Teaching Diagnostic Reasoning for Physicians.

BACKGROUND: Feedback is an aspect of teaching strategy that facilitates the learners to achieve expertise in the necessary skills for effective diagnostic reasoning. Several studies have demonstrated that student response systems (SRSs) are useful for enhancing learner engagement and obtaining immediate feedback. We aimed to examine the experiences of learners who used SRSs in a diagnostic reasoning class. METHODS: In 2016, an observational study was conducted on a 4-hour training course on "improving physicians' diagnostic process" that included 34 physicians. The Zuvio multimedia online interactive system was used. The learners could use smartphones to respond to the questions. A 5-point Likerttype scale quantitative questionnaire was designed to explore the viewpoints of the learners regarding the students' engagement, feedback, and outcomes. The learners were requested to complete a brief qualitative feedback form that included the following two sections: (1) the benefi ts and (2) the challenges of using SRSs. Qualitative and quantitative methods were used for data analyses. RESULTS: Total 32 participants (response rate: 94%) completed the questionnaire. Most respondents reported that using the SRSs enabled them to concentrate more effectively, express themselves in a stressfree environment, strengthen their interactions with peers and teachers, improve their participation in discussions, and obtain useful feedback. Three themes were identified from the qualitative results: (1) facilitating learning, (2) hardware limitations, and (3) question-development skills. CONCLUSION: The SRSs can be easily implemented and positively affect the teaching of diagnostic reasoning. However, teachers should develop question-development skills so that the systems function more effectively in the instruction of diagnostic reasoning.

Disco spotlight sign: A sign that may be useful for diagnosis of pneumomediastinum.

The use of ultrasonography for the investigation of pneumomediastinum is limited by the presence of air artifacts. Air accumulation in the mediastinum obscures the heart, sometimes leading to misinterpretation as lung tissue. We found that cardiac apical swinging during the heart cycle, however, can create a uniquely characteristic squeezing of mediastinal free air, producing a sonographic B-line that flashes in and out. We named this dynamic finding, the "disco spotlight" sign. This finding may be useful to confirm the diagnosis of pneumomediastinum.

Association between Chronic Kidney Disease and Risk of Cataract: A Nationwide Retrospective Cohort Study.

BACKGROUND: Previous studies have established a relationship between chronic kidney disease (CKD) and cataract, but the relationship between the severity of renal impairment and risk of cataract is uncertain. This study investigates the relationship between the severity of renal disease and cataract in a nationwide sample from Taiwan. METHODS: The cohort from 1-million National Health Insurance beneficiaries from Taiwan was retrospectively analyzed. All adult beneficiaries were followed from January 1, 2005 until December 31, 2013, to identify patients who underwent cataract surgeries. On the basis of the ambulatory care records, those diagnosed with CKD (ICD-9-CM code: 585) during the follow-up period were enrolled as CKD patients after careful evaluation. Each patient with CKD was age- and gender-matched with 4 individuals who did not have CKD. Cox regression models were applied to compare the hazard of cataract surgery in individuals with and without CKD. Subgroup analysis was used to compare patients with end-stage renal disease (ESRD) with age- and gender-matched non-CKD individuals. ESRD was defined by CKD patients who need regular renal replacement therapy. The same method was applied to evaluate hazard ratios (HRs). RESULTS: After age and gender matching, there were 11,881 patients in the CKD group and 47,524 in the non-CKD group. After control for possible confounding, the adjusted HR (aHR) of cataract was 1.84 (95% CI 1.73-1.95) for the CKD group. Subgroup analysis of patients with ESRD (n = 3,209) and non-CKD individuals (n = 12,836), with matching done on the basis of age and gender, indicated an aHR of cataract was 2.33 (95% CI 2.10-2.59) for the ESRD group. CONCLUSIONS: This study indicates a relationship between CKD and cataract, and suggests that the risk for cataract increases with the severity of renal impairment.

Increased risk of ischemic stroke in patients with burn injury: a nationwide cohort study in Taiwan.

BACKGROUND: Conflicting results have been obtained by studies attempting to assess the risks of ischemic stroke in patients with burn injury, while the long-term risk of stroke in survivors of burn injury remains unexplored. We evaluated whether the risk of ischemic stroke in patients hospitalized with burn injury in Taiwan is higher when compared to the general population. METHODS: The data from one million National Health Insurance (NHI) adult beneficiaries were evaluated from January 1, 2005 until December 31, 2012 to identify those who developed ischemic stroke. Each identified patient with burn injury was matched with one hundred unexposed patients based on a high-dimensional propensity score. Cox regression models were applied to compare the risks of the development of ischemic stroke in the matched cohorts. RESULTS: A total of 743,237 patients were enrolled. After matching, 1,763 burn injury patients and 176,300 unexposed patients were selected and compared. The adjusted hazard ratio of ischemic stroke was significantly increased in burn injury patients (1.84; 95% CI, 1.43-2.36). A subgroup analysis based on patients who survived longer than 12 months in the matched cohort also revealed higher hazard ratio in the burn injury patients (1.54; 95% CI, 1.11-2.13). CONCLUSION: The risk of ischemic stroke is significantly higher in patients hospitalized with burn injury than in the general population, and these risks may extend longer than expected.

Transient hyperammonemia in seizures: a prospective study.

PURPOSE: To investigate the incidence and duration of transient hyperammonemia in seizures and to verify the significant confounders related to transient hyperammonemia in seizures. METHODS: One hundred twenty-one noncirrhotic adult patients with seizures admitted to the emergency department were enrolled in the study. Laboratory examination was performed, including plasma ammonia level assessment. In addition, the basic parameters, underlying systemic diseases, and seizure-related conditions were assessed. The patients were classified into a group with hyperammonemia on arrival and a group without, in order to compare seizure-related adverse events that occurred during a 9-month period. KEY FINDINGS: The incidence of hyperammonemia in patients with seizures was 67.77%. Plasma ammonia levels in patients with generalized tonic-clonic (GTC) seizures were significantly higher than those in patients in the non-GTC seizure group (median 174.5 vs. 47 µg/dl; proportion 76.5% vs. 21.1%; p < 0.001). Median plasma ammonia levels decreased spontaneously from 250 to 54 µg/dl (p < 0.00001) in an average interval of 466.79 min. GTC seizures (p < 0.0001), male gender (p < 0.0001), bicarbonate (p < 0.0001), diabetes (p = 0.0139), and alcohol-related seizures (p = 0.0002) were significant factors associated with hyperammonemia on arrival. No significant differences related to admission rates or mortalities were found between the two groups. SIGNIFICANCE: The presence of transient hyperammonemia in patients with seizures is significantly related to GTC seizures, male gender, bicarbonate, diabetes, and alcohol-related seizures. The appropriate period to study ammonia levels following a seizure event is within 8 h. Because these phenomena are self-limited, ammonia-lowering management are not necessary. Hyperammonemia on arrival is not necessarily related to adverse outcomes.

Bedside ultrasonography as a safe and effective tool to diagnose acute epiglottitis.

Acute epiglottitis is a true airway emergency in the emergency department (ED). The patient may appear very toxic and rapidly progress to respiratory distress and life-threatening condition. The inflammatory process includes not only epiglottis but also the rest of the supraglottic area including the vallecula, aryepiglottic folds, and arytenoids. Soft tissue swelling over this windpipe area can be very dramatic. The criterion standard of diagnosis is direct inspection of cherry red and swollen epiglottis by laryngoscopy in the operation room with immediate access to anesthetists or ear, nose, and throat specialists. However, before the patients are well prepared, the clinical condition may critically go downhill; and any intention to visualize the throat can result in severe and fatal airway spasm. Thumbprint sign on lateral radiography of neck is typical, but it may be extremely risky to let a patient leave the consulting room for the study if respiratory distress has developed. We demonstrate a safe and practical way to investigate the epiglottis by bedside ultrasonography to visualize the "alphabet P sign" in a longitudinal view through thyrohyoid membrane by emergency physician in the ED.