Identification of four latent classes of acute respiratory distress syndrome using PaO2/FIO2 ratio: an observational cohort study.

Biological phenotypes in patients with the acute respiratory distress syndrome (ARDS) have previously been described. We hypothesized that the trajectory of PaO2/FIO2 ratio could be used to identify phenotypes of ARDS. We used a retrospective cohort analysis of an ARDS database to identify latent classes in the trajectory of PaO2/FIO2 ratio over time. We included all adult patients admitted to an intensive care unit who met the Berlin criteria for ARDS over a 4-year period in tertiary adult intensive care units in Manitoba, Canada. Baseline demographics were collected along with the daily PaO2/FIO2 ratio collected on admission and on days 1-7, 14 and 28. We used joint growth mixture modeling to test whether ARDS patients exhibit distinct phenotypes with respect to both longitudinal PaO2/FIO2 ratio and survival. The resulting latent classes were compared on several demographic variables. In our study group of 209 patients, we found that four latent trajectory classes of PaO2/FIO2 ratio was optimal. These four classes differed in their baseline PaO2/FIO2 ratio and their trajectory of improvement during the 28 days of the study. Despite similar baseline characteristics the hazard for death for the classes differed over time. This difference was largely driven by withdrawal of life sustaining therapy in one of the classes. Latent classes were identified in the trajectory of the PaO2/FIO2 ratio over time, suggesting the presence of different ARDS phenotypes. Future studies should confirm the existence of this finding and determine the cause of mortality differences between classes.

Predictors of acute kidney injury after lung resection surgery: a retrospective case-control study.

PURPOSE: Patients undergoing lung resection are at increased risk for acute kidney injury (AKI) in the immediate postoperative period, with important consequences for longer term morbidity and mortality. Lung resection surgery has unique considerations that could increase the risk of AKI, including lung resection volume, duration of one-lung ventilation (OLV), and intraoperative fluid restriction. Yet, specific risk factor data are lacking. The objective of this study was to identify independent risk factors for early AKI after lung resection surgery. METHODS: We conducted a retrospective case-control study of all patients presenting for elective lung resection surgery at an academic medical centre over a four-year period. Cases were patients who experienced an AKI and control patients were those who did not experience an AKI, based on KDIGO criteria. Baseline demographics and comorbidities along with duration of OLV and amount of lung resected were collected by retrospective chart review. The data were analyzed using multivariable logistic regression to identify independent predictors of AKI. RESULTS: Acute kidney injury occurred within 48 hr in 57/1,045 (5.5%; 95% confidence interval, 4.2 to 7.0) of patients. On multivariable analysis, our model of best fit included preoperative serum creatinine, male sex, use of angiotensin II receptor blockers, and duration of OLV. The rate of complications, intensive care unit admission, and risk of death were all higher in the group of patients who experienced AKI. CONCLUSIONS: Acute kidney injury occurs frequently after lung resection surgery and is associated with increased risk of postoperative complications. Increased duration of OLV may be a risk factor for AKI in this population.

RéSUMé: OBJECTIF: Les patient·es bénéficiant d'une résection pulmonaire courent un risque accru d'insuffisance rénale aiguë (IRA) en période postopératoire immédiate, avec des conséquences importantes pour la morbidité et la mortalité à long terme. La chirurgie de résection pulmonaire entraîne des considérations uniques qui pourraient augmenter le risque d'IRA, notamment le volume de la résection pulmonaire, la durée de la ventilation unipulmonaire (VUP) et la restriction liquidienne peropératoire. Pourtant, les données spécifiques sur les facteurs de risque font défaut. L'objectif de cette étude était d'identifier les facteurs de risque indépendants d'IRA précoce après une chirurgie de résection pulmonaire. MéTHODE: Nous avons mené une étude cas témoins rétrospective de toute la patientèle se présentant pour une chirurgie de résection pulmonaire non urgente dans un centre médical universitaire sur une période de quatre ans. Les cas étaient des patient·es qui ont présenté une IRA et des patient·es témoins qui n'ont pas eu d'IRA, selon les critères KDIGO. Les données démographiques et les comorbidités de base ainsi que la durée de la VUP et le volume de poumon réséqué ont été recueillis par examen rétrospectif des dossiers. Les données ont été analysées à l'aide d'une régression logistique multivariée afin d'identifier des prédicteurs indépendants d'IRA. RéSULTATS: Une insuffisance rénale aiguë est survenue dans les premières 48 heures postopératoires chez 57/1045 (5,5 %; intervalle de confiance à 95 %, 4,2 à 7,0) des patient·es. Sur l'analyse multivariée, notre modèle de meilleur ajustement incluait la créatininémie préopératoire, le sexe masculin, l'utilisation d'antagonistes des récepteurs de l'angiotensine II et la durée de la VUP. Le taux de complications, l'admission en unité de soins intensifs et le risque de décès étaient tous plus élevés dans le groupe de patient·es ayant présenté une IRA. CONCLUSION: L'insuffisance rénale aiguë survient fréquemment après une chirurgie de résection pulmonaire et est associée à un risque accru de complications postopératoires. Une durée prolongée de VUP pourrait constituer un facteur de risque d'IRA dans cette population.

Emergency airway management in a tertiary trauma centre (AIRMAN): a one-year prospective longitudinal study.

PURPOSE: Emergency airway management can be associated with a range of complications including long-term neurologic injury and death. We studied the first-pass success rate with emergency airway management in a tertiary care trauma centre. Secondary outcomes were to identify factors associated with first-pass success and factors associated with adverse events peri-intubation. METHODS: We performed a single-centre, prospective, observational study of patients ≥ 17 yr old who were intubated in the emergency department (ED), surgical intensive care unit (SICU), medical intensive care unit (MICU), and inpatient wards at our institution. Ethics approval was obtained from the local research ethics board. RESULTS: In a seven-month period, there were 416 emergency intubations and a first-pass success rate of 73.1%. The first-pass success rates were 57.5% on the ward, 66.1% in the intensive care units (ICUs) and 84.3% in the ED. Equipment also varied by location; videolaryngoscopy use was 65.1% in the ED and only 10.6% on wards. A multivariate regression model using the least absolute shrinkage and selection algorithm (LASSO) showed that the odds ratios for factors associated with two or more intubation attempts were location (wards, 1.23; MICU, 1.24; SICU, 1.19; reference group, ED), physiologic instability (1.19), an anatomically difficult airway (1.05), hypoxemia (1.98), lack of neuromuscular blocker use (2.28), and intubator inexperience (1.41). CONCLUSIONS: First-pass success rates varied widely between locations within the hospital and were less than those published from similar institutions, except for the ED. We are revamping ICU protocols to improve the first-pass success rate.

RéSUMé: OBJECTIF: La prise en charge d'urgence des voies aériennes peut être associée à une multitude de complications, y compris des lésions neurologiques à long terme et la mort. Nous avons étudié le taux de réussite à la première tentative lors de la prise en charge d'urgence des voies aériennes dans un centre de traumatologie tertiaire. Les critères d'évaluation secondaires étaient l'identification des facteurs associés à la réussite de la première tentative et des facteurs associés aux événements indésirables péri-intubation. MéTHODE: Nous avons réalisé une étude observationnelle prospective monocentrique sur des patients âgés de 17 ans ou plus qui avaient été intubés à l'urgence, à l'unité de soins intensifs chirurgicaux (USIC), à l'unité de soins intensifs médicaux (USIM) et aux étages dans notre établissement. L'approbation a été obtenue du comité d'éthique de la recherche local. RéSULTATS: Au cours d'une période de sept mois, il y a eu 416 intubations d'urgence et un taux de réussite à la première tentative de 73,1 %. Les taux de réussite à la première tentative étaient de 57,5 % aux étages, de 66,1 % dans les unités de soins intensifs (USI) et de 84,3 % à l'urgence. Le matériel variait également selon l'emplacement; l'utilisation de la vidéolaryngoscopie était de 65,1 % à l'urgence et de seulement 10,6 % aux étages. Un modèle de régression multivariée utilisant l'algorithme LASSO (Least Absolute Shrinkage and Selection Algorithm) a montré que les rapports de cotes pour les facteurs associés à deux tentatives d'intubation ou plus étaient l'emplacement (étages, 1,23; USIM, 1,24; USIC, 1,19; groupe de référence, urgence), l'instabilité physiologique (1,19), des voies aériennes présentant des complications anatomiques (1,05), l'hypoxémie (1,98), la non-utilisation de bloqueurs neuromusculaires (2,28) et l'inexpérience de la personne pratiquant l'intubation (1,41). CONCLUSION: Les taux de réussite à la première tentative variaient considérablement d'un emplacement à l'autre au sein de l'hôpital et étaient inférieurs à ceux publiés par des établissements comparables, à l'exception du service des urgences. Nous retravaillons les protocoles des soins intensifs afin d'améliorer le taux de réussite à la première tentative.

A prospective observational study comparing outcomes before and after the introduction of an intubation protocol during the COVID-19 pandemic.

OBJECTIVE: Orotracheal intubation is a life-saving procedure commonly performed in the Intensive Care unit and Emergency Department as a part of emergency airway management. Prior to the COVID-19 pandemic, our center undertook a prospective observational study to characterize emergency intubation performed in the emergency department and critical care settings at Manitoba's largest tertiary hospital. During this study, a natural experiment emerged when a standardized "COVID-Protected Rapid Sequence Intubation Protocol" was implemented in response to the pandemic. The resultant study aimed to answer the question; in adult ED patients undergoing emergent intubation by EM and CCM teams, does the use of a "COVID-Protected Rapid Sequence Intubation Protocol" impact first-pass success or other intubation-related outcomes? METHODS: A single-center prospective quasi-experimental before and after study was conducted. Data were prospectively collected on consecutive emergent intubations. The primary outcome was the difference in first-pass success rates. Secondary outcomes included best Modified Cormack-Lehane view, hypoxemia, hypotension, esophageal intubation, cannot intubate cannot oxygenate scenarios, CPR post intubation, vasopressors required post intubation, Intensive Care Unit (ICU) mortality, ICU length of stay (LOS), and mechanical ventilation days. RESULTS: Data were collected on 630 patients, 416 in the pre-protocol period and 214 in the post-protocol period. First-pass success rates in the pre-protocol period were found to be 73.1% (n = 304). Following the introduction of the protocol, first-pass success rates increased to 82.2% (n = 176, p = 0.0105). There was a statistically significant difference in Modified Cormack-Lehane view favoring the protocol (p = 0.0191). Esophageal intubation rates were found to be 5.1% pre-protocol introduction versus 0.5% following the introduction of the protocol (p = 0.0172). CONCLUSION: A "COVID-Protected Protocol" implemented by Emergency Medicine and Critical Care teams in response to the COVID-19 pandemic was associated with increased first-pass success rates and decreases in adverse events.

RéSUMé: OBJECTIFS: L'intubation orotrachéale est une procédure de sauvetage couramment réalisée dans l'unité de soins intensifs et le service des urgences dans le cadre de la gestion des voies aériennes d'urgence. Avant la pandémie de COVID-19, notre centre a entrepris une étude prospective d'observation pour caractériser l'intubation d'urgence effectuée dans le service des urgences et les établissements de soins intensifs du plus grand hôpital tertiaire du Manitoba. Au cours de cette étude, une expérience naturelle est apparue lorsqu'un " protocole d'intubation à séquence rapide protégé contre le COVID " standardisé a été mis en œuvre en réponse à la pandémie. L'étude qui en a résulté visait à répondre à la question suivante : chez les patients adultes des urgences soumis à une intubation urgente par les équipes de médecine d'urgence et de médecine de soins critiques, l'utilisation d'un " protocole d'intubation à séquence rapide protégé par COVID " a-t-elle un impact sur la réussite du premier passage ou sur d'autres résultats liés à l'intubation ? MéTHODE: Une étude prospective quasi-expérimentale avant et après a été menée dans un seul centre. Les données ont été recueillies prospectivement sur des intubations émergentes consécutives. Le résultat principal était la différence entre les taux de réussite au premier passage. Les résultats secondaires comprenaient la meilleure vue de Cormack­Lehane modifiée, l'hypoxémie, l'hypotension, l'intubation œsophagienne, les scénarios d'impossibilité d'intubation et d'oxygénation, la réanimation cardio-pulmonaire après l'intubation, les vasopresseurs nécessaires après l'intubation, la mortalité en unité de soins intensifs (USI), la durée de séjour en USI et les jours de ventilation mécanique. RéSULTATS: Des données ont été recueillies sur 630 patients, 416 dans la période pré-protocole et 214 dans la période post-protocole. Les taux de réussite au premier passage dans la période pré-protocole se sont avérés être de 73,1 % (n = 304). Suite à l'introduction du protocole, les taux de réussite au premier passage ont augmenté à 82,2 % (n = 176, p = 0,0105). Il y avait une différence statistiquement significative dans la vue Cormack­Lehane modifiée en faveur du protocole (p = 0,0191). Les taux d'intubation œsophagienne se sont avérés être de 5,1 % avant l'introduction du protocole contre 0,5 % après l'introduction du protocole (p = 0,0172). CONCLUSION: Un « protocole protégé contre la COVID ¼ mis en œuvre par les équipes de médecine d'urgence et de médecine de soins critiques en réponse à la pandémie de COVID-19 a été associé à une augmentation des taux de réussite du premier passage et à une diminution des événements indésirables.

Differential Infectivity of Original and Delta Variants of SARS-CoV-2 in Children Compared to Adults.

Although children of all ages are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, they have not been implicated as major drivers of transmission thus far. However, it is still unknown if this finding holds true with new variants of concern (VOC), such as Delta (B.1.617.2). This study aimed to examine differences in both viral RNA (as measured by cycle threshold [CT]) and viable-virus levels from children infected with Delta and those infected with original variants (OV). Furthermore, we aimed to compare the pediatric population infection trends to those in adults. We obtained 690 SARS-CoV-2 RT-PCR positive nasopharyngeal swabs from across Manitoba, Canada, which were further screened for mutations characteristic of VOC. Aliquots of sample were then provided for TCID50 (50% tissue culture infective dose) assays to determine infectious titers. Using a variety of statistical analyses we compared CT and infectivity of VOC in different age demographics. Comparing 122 Delta- to 175 OV-positive nasopharyngeal swab samples from children, we found that those infected with Delta are 2.7 times more likely to produce viable SARS-CoV-2 with higher titers (in TCID50 per milliliter), regardless of viral RNA levels. Moreover, comparing the pediatric samples to 130 OV- and 263 Delta-positive samples from adults, we found only that the Delta pediatric culture-positive samples had titers (TCID50 per milliliter) similar to those of culture-positive adult samples. IMPORTANCE These important findings show that children may play a larger role in viral transmission of Delta than for previously circulating SARS-CoV-2 variants. Additionally, they may suggest a mechanism for why Delta has evolved to be the predominant circulating variant.

Persistence of live virus in critically ill patients infected with SARS-COV-2: a prospective observational study.

BACKGROUND: Research on the duration of infectivity of ICU patients with COVID-19 has been sparse. Tests based on Reverse Transcriptase polymerase chain reaction (RT-PCR) detect both live virus and non-infectious viral RNA. We aimed to determine the duration of infectiousness based on viral culture of nasopharyngeal samples of patients with COVID-19. METHODS: Prospective observational study in adult intensive care units with a diagnosis of COVID-19 Pneumonia. Patients had repeated nasopharyngeal sampling performed after day 10 of ICU admission. Culture positive rate (based on viral culture on Vero cells in a level 4 lab) and Cycle threshold from RT-PCR were measured. RESULTS: Nine patients of the 108 samples (8.3%, 95% CI 3.9-15.2%) grew live virus at a median of 13 days (interquartile range 11-19) after their initial positive test. 74.1% of patients were RT-PCR positive but culture negative, and the remaining (17.6%) were RT-PCR and culture negative. Cycle threshold showed excellent ability to predict the presence of live virus, with a Ct < 25 with an AUC of 0.90 (95% CI 0.83-0.97, p < 0.001). The specificity of a Ct > 25 to predict negative viral culture was 100% (95% CI 70-100%). CONCLUSION: 8.3% of our ICU patients with COVID-19 grew live virus at a median of 13 days post-initial positive RT-PCR test. Severity of illness, use of mechanical ventilation, and time between tests did not predict the presence of live virus. Cycle threshold of > 25 had the best ability to determine the lack of live virus in these patents.

Tidal volume during 1-lung ventilation: A systematic review and meta-analysis.

BACKGROUND: The selection of tidal volumes for 1-lung ventilation remains unclear, because there exists a trade-off between oxygenation and risk of lung injury. We conducted a systematic review and meta-analysis to determine how oxygenation, compliance, and clinical outcomes are affected by tidal volume during 1-lung ventilation. METHODS: A systematic search of MEDLINE and EMBASE was performed. A systematic review and random-effects meta-analysis was conducted. Pooled mean difference estimated arterial oxygen tension, compliance, and length of stay; pooled odds ratio was calculated for composite postoperative pulmonary complications. Risk of bias was determined using the Cochrane risk of bias and Newcastle-Ottawa tools. RESULTS: Eighteen studies were identified, comprising 3693 total patients. Low tidal volumes (5.6 [±0.9] mL/kg) were not associated with significant differences in partial pressure of oxygen (-15.64 [-88.53-57.26] mm Hg; P = .67), arterial oxygen tension to fractional intake of oxygen ratio (14.71 [-7.83-37.24]; P = .20), or compliance (2.03 [-5.22-9.27] mL/cmH2O; P = .58) versus conventional tidal volume ventilation (8.1 [±3.1] mL/kg). Low versus conventional tidal volume ventilation had no significant impact on hospital length of stay (-0.42 [-1.60-0.77] days; P = .49). Low tidal volumes are associated with significantly decreased odds of pulmonary complications (pooled odds ratio, 0.40 [0.29-0.57]; P < .0001). CONCLUSIONS: Low tidal volumes during 1-lung ventilation do not worsen oxygenation or compliance. A low tidal volume ventilation strategy during 1-lung ventilation was associated with a significant reduction in postoperative pulmonary complications.

Comparaison de l'infectivité du coronavirus du syndrome respiratoire aigu sévère 2 chez les enfants et les adultes.

CONTEXTE: Le rôle des enfants dans la propagation et la transmission communautaire du coronavirus du syndrome respiratoire aigu sévère 2 (SRAS-CoV-2) est encore mal compris. Nous visons à quantifier l'infectivité du SRAS-CoV-2 d'échantillons nasopharyngés provenant d'enfants comparativement à ceux provenant d'adultes. MÉTHODES: Nous avons obtenu des écouvillons nasopharyngés de cas adultes et pédiatriques de la maladie à coronavirus 2019 (COVID-19) ainsi que de leurs contacts qui ont obtenu un résultat positif à la présence du SRAS-CoV-2 lors d'un test de dépistage au Manitoba entre les mois de mars et décembre 2020. Nous avons comparé la croissance virale en culture cellulaire, les valeurs de cycle seuil de test d'amplification en chaîne par polymérase couplé à une transcription inverse (RT-PCR) de l'enveloppe (E) du gène du SRAS-CoV-2 et de la dose infectieuse pour 50 % de la culture tissulaire (DICT50/mL) entre les adultes et les enfants. RÉSULTATS: Parmi les 305 échantillons positifs à la présence du SRAS-CoV-2 validés par RT-PCR, 97 échantillons provenaient d'enfants de 10 ans et moins, 78 échantillons d'enfants de 11­17 ans et 130 échantillons d'adultes (≥ 18 ans). On a observé une croissance virale en culture dans 31 % des échantillons, dont 18 (19 %) échantillons d'enfants de 10 ans et moins, 18 (23 %) d'enfants de 11­17 ans et 57 (44 %) d'adultes (enfants c. adultes, rapport de cotes 0,45; intervalle de confiance [IC] à 95 % 0,28­0,72). Le cycle seuil était de 25,1 (IC à 95 % 17,7­31,3) chez les enfants de 10 ans et moins, 22,2 (IC à 95 % 18,3­29,0) chez les enfants de 11­17 ans et 18,7 (IC à 95 % 17,9­30,4) chez les adultes (p < 0,001). La DICT50/mL médiane était considérablement plus faible chez les enfants de 11­17 ans (316, écart interquartile [EI] 178­2125) que chez les adultes (5620, EI 1171­17 800, p < 0,001). Le cycle seuil était un indicateur exact d'une culture positive chez les enfants et les adultes (aire sous la courbe de la fonction d'efficacité du récepteur, 0,87, IC à 95 % 0,81­0,93 c. 0,89, IC à 95 % 0,83­0,96, p = 0,6). INTERPRÉTATION: Comparés aux adultes, les enfants qui ont obtenu un résultat positif à un test de dépistage du SRAS-CoV-2 à l'aide d'un écouvillon nasopharyngé étaient moins susceptibles de présenter une croissance du virus en culture et obtenaient un cycle seuil plus élevé et une concentration virale moins élevée, indiquant que les enfants ne sont pas les principaux vecteurs de la transmission du SRAS-CoV-2.

Infectivity of severe acute respiratory syndrome coronavirus 2 in children compared with adults.

BACKGROUND: The role of children in the transmission and community spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. We aimed to quantify the infectivity of SARS-CoV-2 in nasopharyngeal samples from children compared with adults. METHODS: We obtained nasopharyngeal swabs from adult and pediatric cases of coronavirus disease 2019 (COVID-19) and from their contacts who tested positive for SARS-CoV-2 in Manitoba between March and December 2020. We compared viral growth in cell culture, cycle threshold values from the reverse transcription polymerase chain reaction (RT-PCR) of the SARS-CoV-2 envelope (E) gene and the 50% tissue culture infective dose (TCID50/mL) between adults and children. RESULTS: Among 305 samples positive for SARS-CoV-2 by RT-PCR, 97 samples were from children aged 10 years or younger, 78 were from children aged 11-17 years and 130 were from adults (≥ 18 yr). Viral growth in culture was present in 31% of samples, including 18 (19%) samples from children 10 years or younger, 18 (23%) from children aged 11-17 years and 57 (44%) from adults (children v. adults, odds ratio 0.45, 95% confidence interval [CI] 0.28-0.72). The cycle threshold was 25.1 (95% CI 17.7-31.3) in children 10 years or younger, 22.2 (95% CI 18.3-29.0) in children aged 11-17 years and 18.7 (95% CI 17.9-30.4) in adults (p < 0.001). The median TCID50/mL was significantly lower in children aged 11-17 years (316, interquartile range [IQR] 178-2125) than adults (5620, IQR 1171 to 17 800, p < 0.001). Cycle threshold was an accurate predictor of positive culture in both children and adults (area under the receiver-operator curve, 0.87, 95% CI 0.81-0.93 v. 0.89, 95% CI 0.83-0.96, p = 0.6). INTERPRETATION: Compared with adults, children with nasopharyngeal swabs that tested positive for SARS-CoV-2 were less likely to grow virus in culture, and had higher cycle thresholds and lower viral concentrations, suggesting that children are not the main drivers of SARS-CoV-2 transmission.

Characterization of Ebola Virus Risk to Bedside Providers in an Intensive Care Environment.

BACKGROUND: The 2014-2016 Ebola outbreak in West Africa recapitulated that nosocomial spread of Ebola virus could occur and that health care workers were at particular risk including notable cases in Europe and North America. These instances highlighted the need for centers to better prepare for potential Ebola virus cases; including understanding how the virus spreads and which interventions pose the greatest risk. METHODS: We created a fully equipped intensive care unit (ICU), within a Biosafety Level 4 (BSL4) laboratory, and infected multiple sedated non-human primates (NHPs) with Ebola virus. While providing bedside care, we sampled blood, urine, and gastric residuals; as well as buccal, ocular, nasal, rectal, and skin swabs, to assess the risks associated with routine care. We also assessed the physical environment at end-point. RESULTS: Although viral RNA was detectable in blood as early as three days post-infection, it was not detectable in the urine, gastric fluid, or swabs until late-stage disease. While droplet spread and fomite contamination were present on a few of the surfaces that were routinely touched while providing care in the ICU for the infected animal, these may have been abrogated through good routine hygiene practices. CONCLUSIONS: Overall this study has helped further our understanding of which procedures may pose the highest risk to healthcare providers and provides temporal evidence of this over the clinical course of disease.

Stability of SARS-CoV-2 on critical personal protective equipment.

The spread of COVID-19 in healthcare settings is concerning, with healthcare workers representing a disproportionately high percentage of confirmed cases. Although SARS-CoV-2 virus has been found to persist on surfaces for a number of days, the extent and duration of fomites as a mode of transmission, particularly in healthcare settings, has not been fully characterized. To shed light on this critical matter, the present study provides the first comprehensive assessment of SARS-CoV-2 stability on experimentally contaminated personal protective equipment (PPE) widely used by healthcare workers and the general public. Persistence of viable virus was monitored over 21 days on eight different materials, including nitrile medical examination gloves, reinforced chemical resistant gloves, N-95 and N-100 particulate respirator masks, Tyvek, plastic, cotton, and stainless steel. Unlike previous reports, viable SARS-CoV-2 in the presence of a soil load persisted for up to 21 days on experimentally inoculated PPE, including materials from filtering facepiece respirators (N-95 and N-100 masks) and a plastic visor. Conversely, when applied to 100% cotton fabric, the virus underwent rapid degradation and became undetectable by TCID50 assay within 24 h. These findings underline the importance of appropriate handling of contaminated PPE during and following use in high-risk settings and provide interesting insight into the potential utility of cotton in limiting COVID-19 transmission.

The Incidence and Magnitude of Cerebral Desaturation in Traumatic Brain Injury: An Observational Cohort Study.

BACKGROUND: Cerebral ischemia in patients with traumatic brain injury (TBI) may propagate secondary neurological injury. Episodes of cerebral ischemia can be revealed through the use of cerebral oximetry monitoring. The objective of this study was to determine the incidence and severity of regional cerebral oxygen (rSO2) desaturation (rSO2<65%) in patients with severe TBI. Secondary outcomes included changes in other monitoring parameters associated with cerebral desaturation. MATERIALS AND METHODS: In this single-center prospective observational cohort study, cerebral oximetry data were collected continuously for up to 72 hours in 18 adult patients with a diagnosis of severe nonpenetrating TBI who were being mechanically ventilated and undergoing intracranial pressure (ICP) monitoring an in intensive care unit in Canada. Mean arterial pressure (MAP), ICP, and cerebral perfusion pressure were collected at 5-minute intervals during the study period. RESULTS: Twelve of 18 (67%) patients experienced an episode of cerebral desaturation. The median (interquartile range) nadir rSO2 was 57% (51% to 62%). The duration of desaturation was 265 (57 to 1277) minutes or 8.1% (2.6% to 26.0%) of recording time. In all patients, a linear regression analysis of the area under threshold of 65% for rSO2 was moderately correlated with the area above an ICP threshold of 20 mm Hg (R2=0.52; P<0.01). Similarly, there was a modest correlation between rSO2 and MAP (R2=0.41; P<0.01). These relationships also held true for those patients who experienced cerebral desaturation. Patients having episodes of ICP >20 mm Hg were 6 times more likely to have a cerebral desaturation (relative risk: 6.0; 95% confidence interval: 1.3-34.7). CONCLUSIONS: Cerebral desaturations occur frequently in patients with severe TBI, and their duration can be protracted. Episodes of desaturation were moderately correlated with increased ICP and decreased MAP.

Canadian recommendations for training and performance in basic perioperative point-of-care ultrasound: recommendations from a consensus of Canadian anesthesiology academic centres.

Point-of-care ultrasound (POCUS) uses ultrasound at the bedside to aid decision-making in acute clinical scenarios. The increased use of ultrasound for regional anesthesia and vascular cannulation, together with more anesthesiologists trained in transesophageal echocardiography have contributed to the widespread use of POCUS in perioperative care. Despite the support of international experts, the practice of POCUS in perioperative care is variable as Canadian guidelines for anesthesiologists do not currently exist. Using a Delphi process of online surveys and a face-to-face national Canadian meeting, we developed a consensus statement for basic POCUS (bPOCUS) performance and training with a group of national experts from all Canadian universities. The group of experts consisted of 55 anesthesiologists from 12 Canadian universities considered local leaders in the field. An initial exploratory online survey of 47 statements was conducted. These statements were derived from previous generic guidelines or consensus conferences, or were based on current literature. Fourteen statements reached full consensus, 19 had 90-100% agreement, and 14 had less than 90% agreement. Eight new statements were proposed during the national meeting, and all statements without full agreement were discussed. A second online survey included 42 modified or new statements. From this second survey, 16 statements obtained full consensus, 39 had very good agreement, and one had good agreement. The final document includes 56 statements that define the scope of practice and necessary training for perioperative bPOCUS. The statements include five bPOCUS domains: cardiac, lung, airway, gastric, and abdomen. The use of bPOCUS is evolving and will play a significant role in perioperative medicine. This consensus statement aims to define a Canadian national standard on which curricula may be based. It also provides a framework to allow further development of bPOCUS in the perioperative setting.

RéSUMé: L'échographie ciblée (POCUS) utilise l'échographie au chevet des patients pour faciliter la prise de décisions dans les situations cliniques urgentes. L'utilisation accrue de l'échographie pour l'anesthésie régionale et la cannulation vasculaire, ainsi que l'augmentation du nombre d'anesthésologistes formés à l'échocardiographie transesophagienne, ont contribué à l'utilisation généralisée de l'échographie ciblée dans les soins périopératoires. Malgré son endossement par des experts internationaux, la pratique de l'échographie ciblée en soins périopératoires est variable, car il n'existe pas, à l'heure actuelle, de lignes directrices canadiennes destinées aux anesthésiologistes. À l'aide d'un processus Delphi de sondages en ligne et d'une réunion nationale canadienne en personne, un groupe d'experts nationaux provenant de toutes les universités canadiennes a élaboré une déclaration consensuelle pour la formation de base en et l'exécution de l'échographie ciblée (bPOCUS). Le groupe d'experts était composé de 55 anesthésiologistes issus de 12 universités canadiennes considérés comme des chefs de file locaux dans le domaine. Un premier sondage exploratoire en ligne comportant 47 énoncés a été réalisé. Ces énoncés étaient dérivés de lignes directrices antérieures ou de conférences consensuelles, ou étaient fondés sur la littérature actuelle. Quatorze énoncés ont obtenu un consensus complet, 19 ont atteint un taux de 90 à 100 %, et 14 ont obtenu moins de 90 % d'accord. Huit nouveaux énoncés ont été proposés au cours de la réunion nationale, et tous les énoncés n'ayant pas obtenu d'accord complet ont été discutés. Un deuxième sondage en ligne comprenait 42 énoncés modifiés ou nouveaux. Dans ce deuxième sondage, 16 énoncés ont obtenu un consensus total, 39 un très bon accord et un énoncé un bon accord. Le document final comporte 56 énoncés qui définissent le champ de pratique et la formation nécessaire pour l'échographie ciblée périopératoire de base. Les énoncés portent sur cinq domaines de l'échographie ciblée de base : échographie cardiaque, pulmonaire, des voies respiratoires, gastrique et abdominale. L'utilisation de l'échographie ciblée de base évolue et jouera un rôle important en médecine périopératoire. Cette déclaration consensuelle vise à définir une norme nationale canadienne sur laquelle les programmes d'études pourront s'appuyer. Elle fournit également un cadre pour encourager le développement ultérieur de l'échographie ciblée de base dans un contexte périopératoire.

Adult cardiac surgery and the COVID-19 pandemic: Aggressive infection mitigation strategies are necessary in the operating room and surgical recovery.

The COVID-19 pandemic necessitates aggressive infection mitigation strategies to reduce the risk to patients and healthcare providers. This document is intended to provide a framework for the adult cardiac surgeon to consider in this rapidly changing environment. Preoperative, intraoperative, and postoperative detailed protective measures are outlined. These are guidance recommendations during a pandemic surge to be used for all patients while local COVID-19 disease burden remains elevated.

Predicting Infectious Severe Acute Respiratory Syndrome Coronavirus 2 From Diagnostic Samples.

BACKGROUND: Reverse-transcription polymerase chain reaction (RT-PCR) has become the primary method to diagnose viral diseases, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RT-PCR detects RNA, not infectious virus; thus, its ability to determine duration of infectivity of patients is limited. Infectivity is a critical determinant in informing public health guidelines/interventions. Our goal was to determine the relationship between E gene SARS-CoV-2 RT-PCR cycle threshold (Ct) values from respiratory samples, symptom onset to test (STT), and infectivity in cell culture. METHODS: In this retrospective cross-sectional study, we took SARS-CoV-2 RT-PCR-confirmed positive samples and determined their ability to infect Vero cell lines. RESULTS: Ninety RT-PCR SARS-CoV-2-positive samples were incubated on Vero cells. Twenty-six samples (28.9%) demonstrated viral growth. Median tissue culture infectious dose/mL was 1780 (interquartile range, 282-8511). There was no growth in samples with a Ct > 24 or STT > 8 days. Multivariate logistic regression using positive viral culture as a binary predictor variable, STT, and Ct demonstrated an odds ratio (OR) for positive viral culture of 0.64 (95% confidence interval [CI], .49-.84; P < .001) for every 1-unit increase in Ct. Area under the receiver operating characteristic curve for Ct vs positive culture was OR, 0.91 (95% CI, .85-.97; P < .001), with 97% specificity obtained at a Ct of > 24. CONCLUSIONS: SARS-CoV-2 Vero cell infectivity was only observed for RT-PCR Ct < 24 and STT < 8 days. Infectivity of patients with Ct > 24 and duration of symptoms > 8 days may be low. This information can inform public health policy and guide clinical, infection control, and occupational health decisions. Further studies of larger size are needed.

Adult Cardiac Surgery and the COVID-19 Pandemic: Aggressive Infection Mitigation Strategies Are Necessary in the Operating Room and Surgical Recovery.

The COVID-19 pandemic necessitates aggressive infection mitigation strategies to reduce the risk to patients and healthcare providers. This document is intended to provide a framework for the adult cardiac surgeon to consider in this rapidly changing environment. Preoperative, intraoperative, and postoperative detailed protective measures are outlined. These are guidance recommendations during a pandemic surge to be used for all patients while local COVID-19 disease burden remains elevated.

Positive end-expiratory pressure and recruitment maneuvers during one-lung ventilation: A systematic review and meta-analysis.

BACKGROUND: It is unclear how positive end-expiratory pressure (PEEP) and recruitment maneuvers impact patients during one-lung ventilation (OLV). We conducted a systematic review and meta-analysis of the effect of lung recruitment and PEEP on ventilation and oxygenation during OLV. METHODS: A systematic review and random-effects meta-analysis were performed. Mean difference with standard deviation was calculated. Included studies were evaluated for quality and risk of bias using the Cochrane Risk of Bias tool and the modified Newcastle-Ottawa Score where appropriate. RESULTS: In total, 926 articles were identified, of which 16 were included in meta-analysis. Recruitment maneuvers increased arterial oxygen tension (PaO2) by 82 mm Hg [20, 144 mm Hg] and reduced dead-space by 5.9% [3.8, 8.0%]. PEEP increased PaO2 by 30.3 mm Hg [11.9, 48.6 mm Hg]. Subgroup analysis showed a significant increase in PaO2 (P = .0003; +35.4 mm Hg [16.2, 54.5 mm Hg]) with PEEP compared with no PEEP but no such difference in comparisons with PEEP-treated controls. No significant difference in PaO2 was observed between "high" and "low" PEEP-treated subgroups (P = .29). No significant improvement in PaO2 was observed for subgroups coadministered PEEP, lung recruitment, and low tidal volumes. PEEP was associated with a modest but statistically significant increase in compliance (P = .03; 4.33 mL/cmH2O [0.33, 8.32]). High risk of bias was identified in the majority of studies. Considerable heterogeneity was observed. CONCLUSIONS: Recruitment maneuvers and PEEP have physiologic advantages during OLV. The optimal use of PEEP is yet to be determined. The evidence is limited by heavy use of surrogate outcomes. Future studies with clinical outcomes are necessary to determine the impact of recruitment maneuvers and PEEP during OLV.

Correction to: Impact of intensive care unit supportive care on the physiology of Ebola virus disease in a universally lethal non-human primate model.

Please note that four authors (Logan Banadyga, Alixandra Albietz, Brad Pickering, and Gary Wong) have been erroneously omitted from the author list in the published original article [1].

Impact of intensive care unit supportive care on the physiology of Ebola virus disease in a universally lethal non-human primate model.

BACKGROUND: There are currently limited data for the use of specific antiviral therapies for the treatment of Ebola virus disease (EVD). While there is anecdotal evidence that supportive care may be effective, there is a paucity of direct experimental data to demonstrate a role for supportive care in EVD. We studied the impact of ICU-level supportive care interventions including fluid resuscitation, vasoactive medications, blood transfusion, hydrocortisone, and ventilator support on the pathophysiology of EVD in rhesus macaques infected with a universally lethal dose of Ebola virus strain Makona C07. METHODS: Four NHPs were infected with a universally lethal dose Ebola virus strain Makona, in accordance with the gold standard lethal Ebola NHP challenge model. Following infection, the following therapeutic interventions were employed: continuous bedside supportive care, ventilator support, judicious fluid resuscitation, vasoactive medications, blood transfusion, and hydrocortisone as needed to treat cardiovascular compromise. A range of physiological parameters were continuously monitored to gage any response to the interventions. RESULTS: All four NHPs developed EVD and demonstrated a similar clinical course. All animals reached a terminal endpoint, which occurred at an average time of 166.5 ± 14.8 h post-infection. Fluid administration may have temporarily blunted a rise in lactate, but the effect was short lived. Vasoactive medications resulted in short-lived improvements in mean arterial pressure. Blood transfusion and hydrocortisone did not appear to have a significant positive impact on the course of the disease. CONCLUSIONS: The model employed for this study is reflective of an intramuscular infection in humans (e.g., needle stick) and is highly lethal to NHPs. Using this model, we found that the animals developed progressive severe organ dysfunction and profound shock preceding death. While the overall impact of supportive care on the observed pathophysiology was limited, we did observe some time-dependent positive responses. Since this model is highly lethal, it does not reflect the full spectrum of human EVD. Our findings support the need for continued development of animal models that replicate the spectrum of human disease as well as ongoing development of anti-Ebola therapies to complement supportive care.

Hemodynamic effects of low-dose bupivacaine spinal anesthesia for cesarean section: A randomized controlled trial.

BACKGROUND: Spinal anesthesia is the most common technique for cesarean section. The conventional local anesthetic dose has been decreasing over time to 8-12.5 mg of bupivacaine. Lower doses of bupivacaine may be associated with reduced incidence of hypotension and other complications. This low dose also may be associated with improved maternal cardiac index (CI). We hypothesized that low dose spinal anesthesia using 4.5 mg bupivacaine would result in improved maternal CI when compared with conventional dose (9 mg) intrathecal bupivacaine. METHODS: This randomized controlled trial included all healthy parturients presenting for elective cesarean section. In addition to standard monitors, an arterial line was placed for pulse contour cardiac output measurement. Due to limited data on maternal cardiac output during cesarean section, we had to power our study on recovery room length of stay. Secondary outcomes included the change in maternal CI, fluid administration, vasopressor usage, maternal satisfaction, and adequacy of surgical blockade and recovery time from motor and sensory blockade. RESULTS: The low dose group had significantly faster motor recovery times (132 [122-144] versus. 54 [48-66] min conventional versus. low-dose, respectively, P < 0.01), and a shorter recovery room stay (92 ± 21 vs 70 ± 11 min, conventional vs. low-dose, respectively, P < 0.01, 95% CI -35 to -10 min). There was no difference in CI between the conventional dose and low dose spinal groups. Both groups had a drop in CI with spinal anesthesia. The low-dose group demonstrated equivalent surgical anesthesia and block onset times compared to the conventional group. CONCLUSIONS: Low-dose spinal anesthesia provides adequate surgical anesthesia, improved recovery time, but no difference in maternal cardiac index when compared to conventional dose spinal anesthesia.NCT02046697.