Reducing Ventilator Alarms Through Decreased Rainout in Ventilator Circuits: A Bench Study

Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity settings such as intensive care, surgery, and emergency departments. Alarms are triggered by various devices such as anesthesia machines, ventilators, patient monitors or humidifiers. Heated humidifiers (HH) used with mechanical ventilators, while necessary to prevent other complications associated with mechanical ventilator, may cause condensation in the ventilator circuit, prompting occlusion alarms indicating a risk for the patient. Technological advances in heated humidifier (HH) circuits may reduce rainout and therefore occlusion alarms. Methods:Bench experiments measured alarms and rainout of two commercially available humidifiers (AirLife DuoTherm™ and Fisher & Paykel MR850) and four different pediatric and adult patient’s breathing. The tests examined condensation accumulation after 24 hours of low-, nominal-, or high-flow rates of gas at low-, nominal-, and high-ambient temperature settings. Dual-limb designs of adult- and neonate-sized circuits underwent evaluation. Data on alarms was collected for each system.Results:Low temperature and occlusion alarms were statistically significantly lower in DuoTherm vs. MR850 HH circuits (6 vs. 68 alarms, respectively; p<nn). DuoTherm products accumulated significantly less rainout for all three circuit sizes at all ambient temperatures. In general, the set flow rate did not dramatically affect the amount of rainout for adult and infant circuits, but low versus high ambient temperatures yielded increased rainout for all circuit types (p < 0.02). Conclusions:The DuoTherm HH device and patient circuits developed significantly less alarms due to rainout and low temperatures compared to those from MR850 under all the conditions tested. Such reduction in patient alarms should help reduce alarm fatigue among healthcare workers in critical care settings.

Escaping the nocturnal bottleneck, and the evolution of the dorsal and ventral streams of visual processing in primates

Early mammals were small and nocturnal. Their visual systems had regressed and they had poor vision. After the extinction of the dinosaurs 66 mya, some but not all escaped the ‘nocturnal bottleneck’ by recovering high-acuity vision. By contrast, early primates escaped the bottleneck within the age of dinosaurs by having large forward-facing eyes and acute vision while remaining nocturnal. We propose that these primates differed from other mammals by changing the balance between two sources of visual information to cortex. Thus, cortical processing became less dependent on a relay of information from the superior colliculus (SC) to temporal cortex and more dependent on information distributed from primary visual cortex (V1). In addition, the two major classes of visual information from the retina became highly segregated into magnocellular (M cell) projections from V1 to the primate-specific temporal visual area (MT), and parvocellular-dominated projections to the dorsolateral visual area (DL or V4). The greatly expanded P cell inputs from V1 informed the ventral stream of cortical processing involving temporal and frontal cortex. The M cell pathways from V1 and the SC informed the dorsal stream of cortical processing involving MT, surrounding temporal cortex, and parietal–frontal sensorimotor domains. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.

Prediction across healthcare settings: a case study in predicting emergency department disposition

Several approaches exist today for developing predictive models across multiple clinical sites, yet there is a lack of comparative data on their performance, especially within the context of EHR-based prediction models. We set out to provide a framework for prediction across healthcare settings. As a case study, we examined an ED disposition prediction model across three geographically and demographically diverse sites. We conducted a 1-year retrospective study, including all visits in which the outcome was either discharge-to-home or hospitalization. Four modeling approaches were compared: a ready-made model trained at one site and validated at other sites, a centralized uniform model incorporating data from all sites, multiple site-specific models, and a hybrid approach of a ready-made model re-calibrated using site-specific data. Predictions were performed using XGBoost. The study included 288,962 visits with an overall admission rate of 16.8% (7.9–26.9%). Some risk factors for admission were prominent across all sites (e.g., high-acuity triage emergency severity index score, high prior admissions rate), while others were prominent at only some sites (multiple lab tests ordered at the pediatric sites, early use of ECG at the adult site). The XGBoost model achieved its best performance using the uniform and site-specific approaches (AUC = 0.9–0.93), followed by the calibrated-model approach (AUC = 0.87–0.92), and the ready-made approach (AUC = 0.62–0.85). Our results show that site-specific customization is a key driver of predictive model performance.

Impact of the SARS-CoV-2 (COVID19) pandemic on the morbidity and mortality of high risk patients undergoing surgery: a non-inferiority retrospective observational study

Background During the COVID-19 crisis it was necessary to generate a specific care network and reconvert operating rooms to attend emergency and high-acuity patients undergoing complex surgery. The aim of this study is to classify postoperative complications and mortality and to assess the impact that the COVID-19 pandemic may have had on the results. Methods this is a non-inferiority retrospective observational study. Two different groups of surgical patients were created: Pre-pandemic COVID and Pandemic COVID. Severity of illness was rated according to the Diagnosis-related Groups (DRG) score. Comparisons were made between groups and between DRG severity score-matched samples. Non-inferiority was set at up to 10 % difference for grade III to V complications according to the Clavien-Dindo classification, and up to 2 % difference in mortality. Results A total of 1649 patients in the PreCOVID group and 763 patients in the COVID group were analysed; 371 patients were matched for DRG severity score 3-4 (236 preCOVID and 135 COVID). No differences were found in relation to re-operation (22.5 % vs. 21.5 %) or late admission to critical care unit (5.1 % vs. 4.5 %). Clavien grade III to V complications occurred in 107 patients (45.3 %) in the PreCOVID group and in 56 patients (41.5 %) in the COVID group, and mortality was 12.7 % and 12.6 %, respectively. During the pandemic, 3 % of patients tested positive for Covid-19 on PCR: 12 patients undergoing elective surgery and 11 emergency surgery; there were 5 deaths, 3 of which were due to respiratory failure following Covid-19-induced pneumonia. Conclusions Although this study has some limitations, it has shown the non-inferiority of surgical outcomes during the COVID pandemic, and indicates that resuming elective surgery is safe. Trial registration Clinicaltrials.gov identifier: NCT04780594.

Reducing Ventilator Alarms Through Decreased Rainout in Ventilator Circuits: A Bench Study

Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity settings such as intensive care, surgery, and emergency departments. Alarms are triggered by various devices such as anesthesia machines, ventilators, patient monitors or humidifiers. Heated humidifiers (HH) used with mechanical ventilators, while necessary to prevent other complications associated with mechanical ventilator, may cause condensation in the ventilator circuit, prompting occlusion alarms indicating a risk for the patient. Technological advances in heated humidifier (HH) circuits may reduce rainout and therefore occlusion alarms. Methods:Bench experiments measured alarms and rainout of two commercially available humidifiers (AirLife DuoTherm™ and Fisher & Paykel MR850) and four different pediatric and adult patient’s breathing. The tests examined condensation accumulation after 24 hours of low-, nominal-, or high-flow rates of gas at low-, nominal-, and high-ambient temperature settings. Dual-limb designs of adult- and neonate-sized circuits underwent evaluation. Data on alarms was collected for each system.Results:Low temperature and occlusion alarms were statistically significantly lower in DuoTherm vs. MR850 HH circuits (6 vs. 68 alarms, respectively; p<nn). DuoTherm products accumulated significantly less rainout for all three circuit sizes at all ambient temperatures. In general, the set flow rate did not dramatically affect the amount of rainout for adult and infant circuits, but low versus high ambient temperatures yielded increased rainout for all circuit types (p < 0.02). Conclusions:The DuoTherm HH device and patient circuits developed significantly less alarms due to rainout and low temperatures compared to those from MR850 under all the conditions tested. Such reduction in patient alarms should help reduce alarm fatigue among healthcare workers in critical care settings.

A descriptive study of demographics, triage allocations and patient outcomes at a private emergency centre in Pretoria

Background: Triage aims to detect critically ill patients and to prioritise those with time-sensitive needs, whilst contributing to the efficiency of an emergency centre (EC). International systems have been relatively well researched; however, little data exists on the use of the South African Triage Scale (SATS) in private healthcare settings in South Africa (SA).Methods: A retrospective descriptive study was undertaken. Data relating to demographics, application of triage, time in EC and disposition were collected on all patients presenting to the EC from 1st January to 31st December 2018.Results: A total of 29 055 patients’ data were included. The mean age was 41 years. Most patients were triaged yellow (73.5%); 17.4% were triaged as red and orange. Patients were seen by a doctor in a mean time of 28 min. Delays to be seen exceeded standards for red and orange patients at 8 min and 18 min, respectively. Most patients (76.1%) were discharged; 5.6% were admitted to intensive care unit (ICU)/high care, and 14.4% to general wards. Of patients triaged red and orange, 11.1% and 49.3% were discharged, respectively, whereas 81.7% of yellow patients were discharged home.Conclusion: This study found that most patients were triaged into low acuity categories and were discharged home. High acuity patients were usually admitted to ICU/high care; however, these patients experienced delays in receiving treatment. The causes of these issues, and the implications, remain unknown. Large numbers of high acuity patients were discharged home. Further studies are needed to understand the influence of triage accuracy on these patients’ outcomes.

Epidemiology, management and survival outcomes of adult out-of-hospital traumatic cardiac arrest due to blunt, penetrating or burn injury

BackgroundSurvival from out-of-hospital traumatic cardiac arrest (TCA) is poor. Regional variation exists regarding epidemiology, management and outcomes. Data on prognostic factors are scant. A better understanding of injury patterns and outcome determinants is key to identifying opportunities for survival improvement.MethodsIncluded were adult (≥18 years) out-of-hospital TCA due to blunt, penetrating or burn injury, who were attended by Queensland Ambulance Service paramedics between 1 January 2007 and 31 December 2019. We compared the characteristics of patients who were pronounced dead on paramedic arrival and those receiving resuscitation from paramedics. Intra-arrest procedures were described for attempted-resuscitation patients. Survival up to 6 months postarrest was reported, and factors associated with survival were investigated.Results3891 patients were included; 2394 (61.5%) were pronounced dead on paramedic arrival and 1497 (38.5%) received resuscitation from paramedics. Most arrests (79.8%) resulted from blunt trauma. Motor vehicle collision (42.4%) and gunshot wound (17.7%) were the most common injury mechanisms in patients pronounced dead on paramedic arrival, whereas the most prevalent mechanisms in attempted-resuscitation patients were motor vehicle (31.3%) and motorcycle (20.6%) collisions. Among attempted-resuscitation patients, rates of transport and survival to hospital handover, to hospital discharge and to 6 months were 31.9%, 15.3%, 9.8% and 9.8%, respectively. Multivariable model showed that advanced airway management (adjusted OR 1.84; 95% CI 1.06 to 3.17), intravenous access (OR 5.04; 95% CI 2.43 to 10.45) and attendance of high acuity response unit (highly trained prehospital care clinicians) (OR 2.54; 95% CI 1.25 to 5.18) were associated with improved odds of survival to hospital handover.ConclusionsBy including all paramedic-attended patients, this study provides a more complete understanding of the epidemiology of out-of-hospital TCA. Contemporary survival rates from adult out-of-hospital TCA who receive resuscitation from paramedics may be higher than historically thought. Factors identified in this study as associated with survival may be useful to guide prognostication and treatment.

Critically Ill Children in a Swiss Pediatric Emergency Department With an Interdisciplinary Approach: A Prospective Cohort Study

Objective: Delivery of prompt and adequate care for critically ill and injured children presenting to the pediatric emergency department (PED) is paramount for optimal outcomes. Knowledge of the local epidemiology, patient profile, and presentation modes are key for organizational planning, staff education strategy, and optimal care in a PED. Our aim was to analyze the profile of critically ill and injured children admitted to a tertiary, non-academic Swiss PED, to investigate potential risk factors associated with admission to the pediatric intensive care unit (PICU), and the outcomes mortality and PICU admission.Methods: Prospective cohort study of critically ill and injured children presenting to the PED over a two-year period (2018–2019). Inclusion criteria were Australasian triage scale category (ATS) 1, trauma team activation (TTA), medical emergency response (MER) activation, additional critical care consult, and transfer to an outside hospital.Results: Of 42,579 visits during the two-year period, 347 presentations matched the inclusion criteria (0.81%). Leading presentations were central nervous system (CNS) disorders (26.2%), trauma (25.1%), and respiratory emergencies (24.2%). 288 out of 347 cases (83%) arrived during the day or evening with an even distribution over the days of the week. 128 out of 347 (37%) arrived unexpectedly as walk-ins. 233 (67.15%) were ATS category 1. 51% of the cohort was admitted to PICU. Australasian triage scale category 1 was significantly more common in this group (p = 0.0001). Infants with respiratory disease had an increased risk of PICU transfer compared to other age groups (OR 4.18 [95%CI 2.46, 7.09] p = 0.0001), and this age group presented mainly as walk-in (p = 0.0001). Pediatric intensive care unit admissions had a longer hospital stay (4 [2, 8] days vs. 2 [1, 4] days, p = 0.0001) compared to other patients. 0.045% of all PED patients had to be transferred out. Three deaths (0.86%) occurred in the PED, 10 patients died in the PICU (2.9%).Conclusions: High acuity presentations in the PED were rare, more likely to be young with CNS disorders, trauma and respiratory diseases. A significant proportion were unexpected walk-in presentations, mainly during day and evening shifts. Low exposure to high-acuity patients highlights the importance of deliberate learning and simulation for all professionals in the PED.