Humidity determines penetrance of a latitudinal gradient in genetic selection on the microbiota by Drosophila melanogaster.

The fruit fly Drosophila melanogaster is a model for understanding how hosts and their microbial partners interact as the host adapts to wild environments. These interactions are readily interrogated because of the low taxonomic and numeric complexity of the flies' bacterial communities. Previous work has established that host genotype, the environment, diet, and interspecies microbial interactions can all influence host fitness and microbiota composition, but the specific processes and characters mediating these processes are incompletely understood. Here, we compared the variation in microbiota composition between wild-derived fly populations when flies could choose between the microorganisms in their diets and when flies were reared under environmental perturbation (different humidities). We also compared the colonization of the resident and transient microorganisms. We show that the ability to choose between microorganisms in the diet and the environmental condition of the flies can influence the relative abundance of the microbiota. There were also key differences in the abundances of the resident and transient microbiota. However, the microbiota only differed between populations when the flies were reared at humidities at or above 50% relative humidity. We also show that elevated humidity determined the penetrance of a gradient in host genetic selection on the microbiota that is associated with the latitude the flies were collected from. Finally, we show that the treatment-dependent variation in microbiota composition is associated with variation in host stress survival. Together, these findings emphasize that host genetic selection on the microbiota composition of a model animal host can be patterned with the source geography, and that such variation has the potential to influence their survival in the wild. Importance: The fruit fly Drosophila melanogaster is a model for understanding how hosts and their microbial partners interact as hosts adapt in wild environments. Our understanding of what causes geographic variation in the fruit fly microbiota remains incomplete. Previous work has shown that the D. melanogaster microbiota has relatively low numerical and taxonomic complexity. Variation in the fly microbiota composition can be attributed to environmental characters and host genetic variation, and variation in microbiota composition can be patterned with the source location of the flies. In this work we explored three possible causes of patterned variation in microbiota composition. We show that host feeding choices, the host niche colonized by the bacteria, and a single environmental character can all contribute to variation in microbiota composition. We also show that penetrance of latitudinally-patterned host genetic selection is only observed at elevated humidities. Together, these results identify several factors that influence microbiota composition in wild fly genotypes and emphasize the interplay between environmental and host genetic factors in determining the microbiota composition of these model hosts.

Ventilator Management in Metformin-Associated Lactic Acidosis: A Case Report.

The initiation of mechanical ventilation in the setting of profound metabolic acidosis can be a particular challenge in the transport environment. The classic teaching is that patients with severe acidemia should not be intubated, if possible, because they are often able to better maintain their own compensatory minute ventilation compared with clinician management with the mechanical ventilator. In this case, a patient had profound metformin-associated lactic acidosis with a pH of 6.51 and required intubation for deteriorating mental status with an inability to protect her airway. Maintaining adequate minute ventilation can be directly in conflict with the evidence-based approach of low tidal volume ventilation for all patients. When patients have profound metabolic acidosis without evidence of acute respiratory distress syndrome, increasing the tidal volume slightly to allow for more efficient respiration can be an effective strategy to maintain acid-base status.

Timing of Transport of Patients with COVID-19.

RATIONALE: The objective of this study was to evaluate the risk of mortality or ECMO cannulation for patients with confirmed or suspected COVID-19 transferred from sending hospitals to receiving tertiary care centers as a function of the duration of time at the sending hospital. OBJECTIVE: To determine outcomes of critically ill patients with COVID-19 who were transferred to tertiary or quarternary care medical centers. MATERIALS AND METHODS: Retrospective cohort study of critical care transports of patients to one of seven consortium tertiary care centers from March 1, 2020, through September 4, 2020. Age 14 years and older with confirmed or suspected COVID-19 transported from a sending hospital to a receiving tertiary care center by the critical care transport organization. RESULTS: Patients transported with confirmed or suspected COVID-19 to tertiary care centers had a mortality rate of 38.0%. Neither the number of days admitted, nor the number of days intubated at the sending hospital correlated with mortality (correlation coefficient 0.051 and -0.007, respectively). Similarly, neither the number of days admitted, nor number of days intubated at the sending hospital correlated with ECMO cannulation (correlation coefficient 0.008 and -0.036, respectively). CONCLUSION: It may be reasonable to transfer a critically ill COVID-19 patient to a tertiary care center even if they have been admitted at the sending hospital for several days.

Air Versus Ground Transport Times in an Urban Center.

PURPOSE: Given that the benefits of helicopter transport vary with geography and healthcare systems, we assessed transport times for rotor wing versus ground transport over a 10 year period in an urban setting. MATERIALS AND METHODS: All completed transports from 153 sending hospitals in New England from 2009 through 2018 to 8 local tertiary care centers were extracted from an administrative database. The primary outcome of interest was patient-loaded transport time for rotor wing versus ground transports. Overall, 25,483 patient transports met the inclusion criteria and were included in this study. We assessed patient-loaded transport time for all transports, and determined mean time to arrive at the scene, scene to patient time, the bedside time, and distance at which the patient-loaded transport time was faster for rotor wing than for ground transport. We also performed subgroup analyses, evaluating transport times by time of day, day of the week, and destination. RESULTS: The most common indication for transport was adult trauma, (n = 6,008, 23.6%) followed by adult cardiac (n = 4359, 17.1%), adult neuro (3729 14.6%), and adult medical (n = 3691, 14.5%). The median miles traveled for all transports was 26.0, IQR 14-38, ranging from 1 to 264 miles. The median patient-loaded transport time was 27 min (IQR 15-40) for all transports. Nearly all time intervals were shorter for rotor wing versus ground transports, and patient-loaded transport time was significantly shorter at 15 minutes compared to 38 minutes (IQR 12-22 vs 28-33, p < 0.001). There was no distance at which the patient-loaded transport time was faster for ground transport than for rotor wing. CONCLUSIONS: In over 25,000 transports over 10 years, in a compact metropolitan area with relatively short transport distances and times, the use of the helicopter was associated with substantial time savings.

Interfacility Transport of Critically Ill Patients.

OBJECTIVES: To assess recent advances in interfacility critical care transport. DATA SOURCES: PubMed English language publications plus chapters and professional organization publications. STUDY SELECTION: Manuscripts including practice manuals and standard (1990-2021) focused on interfacility transport of critically ill patients. DATA EXTRACTION: Review of society guidelines, legislative requirements, objective measures of outcomes, and transport practice standards occurred in work groups assessing definitions and foundations of interfacility transport, transport team composition, and transport specific considerations. Qualitative analysis was performed to characterize current science regarding interfacility transport. DATA SYNTHESIS: The Task Force conducted an integrative review of 496 manuscripts combined with 120 from the authors' collections including nonpeer reviewed publications. After title and abstract screening, 40 underwent full-text review, of which 21 remained for qualitative synthesis. CONCLUSIONS: Since 2004, there have been numerous advances in critical care interfacility transport. Clinical deterioration may be mitigated by appropriate patient selection, pretransport optimization, and transport by a well-resourced team and vehicle. There remains a dearth of high-quality controlled studies, but notable advances in monitoring, en route management, transport modality (air vs ground), as well as team composition and training serve as foundations for future inquiry. Guidance from professional organizations remains uncoupled from enforceable regulations, impeding standardization of transport program quality assessment and verification.

American Helicopter Emergency Medical Service Pilots Report to Work Despite High Rates of Sleepiness.

OBJECTIVE: Previous studies on helicopter emergency medical service (HEMS) pilots found a positive correlation among fatigue, nodding off in flight, and accidents. We sought to quantify the amount of sleepiness in HEMS pilots using the Epworth Sleepiness Scale (ESS). METHODS: An anonymous survey was sent via the National EMS Pilots Association emergency medical services listserv including demographics, the ESS, and subjective effects of fatigue on flying. Statistical analyses were performed using the t-test and analysis of variance. RESULTS: Thirty-one surveys were returned. Twenty-one (65%) reported an ESS > 10, indicating excessive daytime sleepiness. Twelve (39%) reported nodding off in flight; 20 (65%) indicated that they should have refused to fly, but only 14 (45%) actually did. En route was the most likely phase of flight to be affected by fatigue (23 [74%]), whereas takeoff (2 [7%]) and landing (2 [7%]) were the least likely to be affected. CONCLUSION: Many HEMS pilots in this small study reported excessive daytime sleepiness. Most respondents indicated that they should have turned down a flight because of fatigue. More research is necessary to quantify the burden of fatigue among HEMS pilots.

A retrospective review of implementation of an inhaled epoprostenol protocol in the emergency department.

INTRODUCTION: Inhaled epoprostenol is a selective pulmonary vasodilator that has shown a potentially broad number of applications in the management of critically ill patients. To date, the vast majority of the literature with regard to efficacy, indications for use, and adverse effects of inhaled epoprostenol is focused on use of this agent in critical care settings, with relatively little literature describing use of inhaled epoprostenol in the Emergency Department. This retrospective review sought to examine instances in which inhaled epoprostenol was administered in the Emergency Department of a tertiary-care, Level I trauma center following implementation of a clinical pathway for administration of this medication for cases of refractory hypoxemia, RV dysfunction, and refractory hypoxemia. Primary outcomes were monitoring for adverse effects (i.e. hypotension), trend in FiO2 requirement over time, and clinical indication for initiation of inhaled epoprostenol. METHODS: An automated review was performed to query cases in which inhaled epoprostenol had been initiated in the Emergency Department following adoption of the inhaled epoprostenol clinical pathway. Cases were excluded if the medication was initiated in the prehospital setting, ordered but not administered, or administered for a period of <1 h. Vital signs and co-administration of vasopressors were followed before and following epoprostenol administration to assess for change over time. Clinical indication of epoprostenol administration was assessed via manual chart review. RESULTS: Inhaled epoprostenol was administered in 20 instances, with 15 cases ultimately meeting inclusion criteria. There were no cases of clinically significant hypotension (MAP <65) in any of the cases in which inhaled epoprostenol was administered in the Emergency Department, and mean vasopressor requirement did not increase over time. A majority of patients saw a reduction in FiO2 requirement following administration of inhaled epoprostenol. The most common indication for initiation of inhaled epoprostenol based on manual chart review was pulmonary embolism. DISCUSSION: In this review of cases in which inhaled epoprostenol was administered following adoption of a clinical pathway for medication administration, there were no cases of hypotension or other adverse effects that appear to be attributable to medication administration. Pulmonary embolism and refractory hypoxemia were the most common noted indications for administration of inhaled epoprostenol. Further research is warranted regarding development of clinical protocols for administration of inhaled pulmonary vasodilators in the Emergency Department setting.

Postintubation Sedation After a Formulary Change From Succinylcholine to Rocuronium in a Critical Care Transport Organization.

OBJECTIVE: Rocuronium is increasingly used as a first-line neuromuscular blocker (NMB) in rapid sequence intubation by transport teams. Prior work has shown that rocuronium is associated with a delay in postintubation sedation compared with intubation with succinylcholine. METHODS: Boston MedFlight is a consortium-based transport organization. In 2017, the intubation protocol and formulary for Boston MedFlight was changed to replace succinylcholine with rocuronium. We performed a retrospective review of patients intubated by the critical care transport teams from January 2017 through December 2019. RESULTS: We analyzed data for 264 intubations, 92 with succinylcholine and 172 with rocuronium. Ketamine and etomidate were the most common induction agents. The mean time from NMB administration to the first dose of sedation was 9.2 minutes (95% confidence interval, 5.4-23.7) for the succinylcholine cohort and 14.8 minutes (95% confidence interval, 8.4-38.0; P < .001) for the rocuronium cohort. After neuromuscular blockade, the total hourly weight-adjusted fentanyl dose was significantly lower for patients intubated with rocuronium compared with succinylcholine. CONCLUSIONS: Intubation with rocuronium was associated with a longer time until the administration of sedation and decreased postneuromuscular blockade fentanyl administration compared with intubation with succinylcholine. These findings suggest opportunities for improvement in sedation and analgesia practices after rocuronium rapid sequence intubation.

Evaluation of a COVID-19 emergency department observation protocol.

OBJECTIVES: Caring for patients with COVID-19 has resulted in a considerable strain on hospital capacity. One strategy to mitigate crowding is the use of ED-based observation units to care for patients who may have otherwise required hospitalization. We sought to create a COVID-19 Observation Protocol for our ED Observation Unit (EDOU) for patients with mild to moderate COVID-19 to allow emergency physicians (EP) to gather more data for or against admission and intervene in a timely manner to prevent clinical deterioration. METHODS: This was a retrospective cohort study which included all patients who were positive for SARS-CoV-2 at the time of EDOU placement for the primary purpose of monitoring COVID-19 disease. Our institution updated the ED Observation protocol partway into the study period. Descriptive statistics were used to characterize demographics. We assessed for differences in demographics, clinical characteristics, and outcomes between admitted and discharged patients. Multivariate logistic regression models were used to assess whether meeting criteria for the ED observation protocols predicted disposition. RESULTS: During the time period studied, 120 patients positive for SARS-CoV-2 were placed in the EDOU for the primary purpose of monitoring COVID-19 disease. The admission rate for patients in the EDOU during the study period was 35%. When limited to patients who met criteria for version 1 or version 2 of the protocol, this dropped to 21% and 25% respectively. Adherence to the observation protocol was 62% and 60% during the time of version 1 and version 2 implementation, respectively. Using a multivariate logistic regression, meeting criteria for either version 1 (OR = 3.17, 95% CI 1.34-7.53, p < 0.01) or version 2 (OR = 3.18, 95% CI 1.39-7.30, p < 0.01) of the protocol resulted in a higher likelihood of discharge. There was no difference in EDOU LOS between admitted and discharged patients. CONCLUSION: An ED observation protocol can be successfully created and implemented for COVID-19 which allows the EP to determine which patients warrant hospitalization. Meeting protocol criteria results in an acceptable admission rate.

Operational Policies and Procedures for Critical Care Transport During a Respiratory Pandemic.

The severe acute respiratory syndrome coronavirus 2 pandemic of 2020 to 2021 created unprecedented challenges for health care organizations, including those in the critical care transport sector. Critical care transport services had to rapidly adjust to changing patient demographics, distribution of diagnoses, and transport utilization stratagem. To evolve with the pandemic, organizations developed new protocols and guidelines in rapid succession. The growth bore out of a need to cater to this new patient population and their safety as well as the safety of the crewmembers from severe acute respiratory syndrome coronavirus 2. The critical changes to operations involved adaptability, efficient communication, continual reassessment, and implementation of novel approaches. Although these lessons learned were specific to coronavirus disease 2019, many processes will apply to future respiratory epidemics and pandemics. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) pandemic of 2020 to 2021 created unprecedented challenges for health care organizations, including critical care transport (CCT) organizations. The changes were numerous, including a change in the patient population, with a rapid decrease in trauma and pediatrics to a preponderance of adult patients with acute hypoxemic respiratory failure. CCT teams were called on to transport these patients at potential risk to themselves, especially early in 2020, before the effectiveness of personal protective equipment (PPE) was determined. Even seemingly simple tasks, such as defining a person under investigation (PUI) for coronavirus disease 2019 (COVID-19), varied from institution to institution, putting transport organizations in the middle of conflicts. Agility has always been an essential part of any CCT organization because clinicians and managers must adapt to an unpredictable environment. However, the frequency and speed of changes occurring during the COVID-19 pandemic were unprecedented. This report offers our best practices based on our experience and the available data. Although these procedures were developed for the COVID-19 pandemic, they will logically apply to future respiratory outbreaks and illuminate helpful changes for otherwise quotidian operations.

Prehospital Mechanical Ventilation: An NAEMSP Position Statement and Resource Document.

Airway emergencies and respiratory failure frequently occur in the prehospital setting. Patients undergoing advanced airway management customarily receive manual ventilations. However, manual ventilation is associated with hypo- and hyperventilation, variable tidal volumes, and barotrauma, among other potential complications. Portable mechanical ventilators offer an important strategy for optimizing ventilation and mitigating ventilatory complications.EMS clinicians, including those performing emergency response as well as interfacility transports, should consider using mechanical ventilation after advanced airway insertion.Prehospital mechanical ventilation techniques, strategies, and parameters should be disease-specific and should mirror in-hospital best practices.EMS clinicians must receive training in the general principles of mechanical ventilation as well as detailed training in the operation of the specific system(s) used by the EMS agency.Patients undergoing mechanical ventilation must receive appropriate sedation and analgesia.

A Case of Bleeding During Infection With COVID-19.

Dr. Patrick Lowe: Our case today is that of a 47-year-old woman who was referred to our emergency department (ED) due to bloody urine, dark tarry stools, red spots on her skin, and bruising throughout her body. Fourteen days prior to presentation, she began exhibiting intermittent fevers, headache, shortness of breath, and a dry cough, and she tested positive for SARS-CoV-2 (the virus that causes COVID-19 pneumonia). Over the 3 days prior to her ED presentation, she experienced a headache that was more intense than the headaches she had been having in the preceding 2 weeks. She reported episodes of both dark urine as well as bright red blood in her urine. In addition, she had multiple dark stools described as tar-like when asked. On the day of her ED presentation, the patient noted a red rash throughout her body. In addition, earlier in the day, she had atraumatic self-limited epistaxis. She denied any falls or head strikes, vision changes, focal weakness or numbness, shortness of breath, chest pain, abdominal pain, or peripheral swelling.

Impact of Emergency Department Crowding on Discharged Patient Experience.

INTRODUCTION: While emergency department (ED) crowding has deleterious effects on patient care outcomes and operational efficiency, impacts on the experience for patients discharged from the ED are unknown. We aimed to study how patient-reported experience is affected by ED crowding to characterize which factors most impact discharged patient experience. METHODS: This institutional review board-exempt, retrospective, cohort study included all discharged adult ED patients July 1, 2020-June 30, 2021 with at least some response data to the the National Research Corporation Health survey, sent to most patients discharged from our large, academic medical center ED. Our query yielded 9,401 unique encounters for 9,221 patients. Based on responses to the summary question of whether the patient was likely to recommend our ED, patients were categorized as "detractors" (scores 0-6) or "non-detractors" (scores 7-10). We assessed the relationship between census and patient experience by 1) computing percentage of detractors within each care area and assessing for differences in census and boarder burden between detractors and non-detractors, and 2) multivariable logistic regression assessing the relationship between likelihood of being a detractor in terms of the ED census and the patient's last ED care area. A second logistic regression controlled for additional patient- and encounter-specific covariates. RESULTS: Survey response rate was 24.8%. Overall, 13.9% of responders were detractors. There was a significant difference in the average overall ED census for detractors (average 3.70 more patients physically present at the time of arrival, 95% CI 2.33-5.07). In unadjusted multivariable analyses, three lower acuity ED care areas showed statistically significant differences of detractor likelihood with changes in patient census. The overall area under the curve (AUC) for the unadjusted model was 0.594 (CI 0.577-0.610). The adjusted model had higher AUC (0.673, CI 0.657-.690]; P<0.001), with the same three care areas having significant differences in detractor likelihood based on patient census changes. Length of stay (OR 1.71, CI 1.50-1.95), leaving against medical advice/without being seen (OR 5.15, CI 3.84-6.89), and the number of ED care areas a patient visited (OR 1.16, CI 1.01-1.33) was associated with an increase in detractor likelihood. CONCLUSION: Patients arriving to a crowded ED and ultimately discharged are more likely to have negative patient experience. Future studies should characterize which variables most impact patient experience of discharged ED patients.

Clinical Policies and Procedures for Critical Care Transport during a Respiratory Pandemic.

The severe acute respiratory syndrome coronavirus disease-2 (SARS-CoV-2) pandemic of 2020-2021 created unprecedented challenges for clinicians in critical care transport (CCT). These CCT services had to rapidly adjust their clinical approaches to evolving patient demographics, a preponderance of respiratory failure, and transport utilization stratagem. Organizations had to develop and implement new protocols and guidelines in rapid succession, often without the education and training that would have been involved pre-coronavirus disease 2019 (COVID-19). These changes were complicated by the need to protect crew members as well as to optimize patient care. Clinical initiatives included developing an awake proning transport protocol and a protocol to transport intubated proned patients. One service developed a protocol for helmet ventilation to minimize aerosolization risks for patients on noninvasive positive pressure ventilation (NIPPV). While these clinical protocols were developed specifically for COVID-19, the growth in practice will enhance the care of patients with other causes of respiratory failure. Additionally, these processes will apply to future respiratory epidemics and pandemics.

Intensive care unit admission for patients with pulmonary hypertension presenting to U.S. Emergency Departments.

INTRODUCTION: Pulmonary hypertension (PH) is an important contributor to morbidity and mortality in patients seeking emergency care, resulting in high acuity presentations and resource utilization. The objective was to characterize the rate of intensive care unit (ICU) admission for PH among adult patients presenting to the emergency department (ED) along with other important clinical outcomes. METHODS: We analyzed data from the State Emergency Department Databases (SEDD) and State Inpatient Databases (SID) from two geographically separated U.S. states (New York and Nebraska). The primary outcome measure was admission to an ICU. Other measures of interest included the hospital admission rate, hospital length of stay (LOS), inpatient mortality, and rate of critical care procedures performed. RESULTS: From 2010 to 2014, in a sample of 34 million ED visits, patients with a diagnosis of PH accounted for 0.71% of all ED visits. Of the PH visits, 20.2% were admitted to the ICU, compared to 2.6% of all other visits (P < 0.001), with an aOR of 1.74 (95% CI 1. 72-1.76). The vast majority (94.6%) of PH patients were admitted to the hospital, compared to 20.5% for all other ED visits (P < 0.001). Hospital LOS and hospital-based mortality were higher in the PH group than for other ED patients. With the exception of invasive mechanical ventilation, a significantly higher percentage of patients with PH admitted to the ICU than other patients underwent all critical care procedures evaluated. CONCLUSIONS: In this study, patients with PH who sought emergency care in U.S. EDs from 2010 to 2014 were significantly more likely to require ICU admission than all other patients. They were also significantly more likely to be admitted to the hospital than all other patients, had longer hospital LOS, increased risk of inpatient mortality, and underwent more critical care procedures. These findings indicate the high acuity of PH patients seeking emergency care and demonstrate the need for additional research into this population.

Critical Care Transport of Patients With COVID-19.

PURPOSE: Critical care transport is associated with a high rate of adverse events, and the risks and outcomes of transporting critically ill patients during the COVID-19 pandemic have not been previously described. MATERIALS AND METHODS: We performed a retrospective review of transports of subjects with suspected or confirmed COVID-19 from sending hospitals to tertiary care hospitals in Boston. Follow-up data were obtained for patients transported between March 1st and April 20th, 2020. RESULTS: Of 254 charts identified, 250 patients were transported. Nine patients (3.5%) had cardiac arrest prior to transport. Twenty-nine (11.6%) had hypotension, 22 (8.8%) had a critical desaturation, and 4 (1.6%) had both en route. Hospital follow-up data were available for 189 patients. Of those intubated during their hospitalization, 44 (25.0%) had died, 59 (33.5%) had been extubated, and 13 (17.6%) had been discharged alive. For the subgroup with prior cardiac arrest, follow-up data available for 6. Of these 6, 2 died and 4 (66.7%) have been discharged alive. CONCLUSIONS: Few patients with COVID-19 had an adverse event in transport. The in-hospital mortality rate was 25%, with a 33.5% extubation rate. Patients resuscitated from cardiac arrest prior to transport had a 66.7% discharge rate among those transported to consortium hospitals.