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Background: Pressure-controlled face mask ventilation (PC-FMV) with positive end-expiratory pressure (PEEP) after apnoea following induction of general anaesthesia prolongs safe apnoea time and reduces atelectasis formation. However, depending on the set inspiratory pressure, a delayed confirmation of a patent airway might occur. We hypothesised that by lowering the peak inspiratory pressure (PIP) when using PC-FMV with PEEP, confirmation of a patent airway would not be delayed as studied by the first return of CO2, compared with manual face mask ventilation (Manual FMV). Methods: This was a single-centre, randomised controlled non-inferiority trial. Seventy adult patients scheduled for elective day-case surgery under general anaesthesia with body mass index between 18.5 and 29.9 kg m(-2), American Society of Anesthesiologists (ASA) classes I-III, and without anticipated difficult FMV, were included. Before the start of pre-oxygenation and induction of general anaesthesia, participants were randomly allocated to receive ventilation with either PC-FMV with PEEP, at a PIP of 11 and a PEEP of 6 cmH(2)O or Manual FMV, with the adjustable pressure-limiting valve set at 11 cmH(2)O. The primary outcome variable was the number of ventilatory attempts needed until confirmation of a patent airway, defined as the return of at least 1.3 kPa CO2. Results: The return of >= 1.3 kPa CO2 on the capnography curve was observed after mean +/- SD, 3.6 +/- 4.2 and 2.5 +/- 1.9 ventilatory attempts/breaths with PC-FMV with PEEP and Manual FMV, respectively. The difference in means (1.1 ventilatory attempts/breaths) had a 99% CI of similar to 1.0 to 3.1, within the accepted upper margin of four breaths for non-inferiority. Conclusion: Following induction of general anaesthesia, PC-FMV with PEEP was used without delaying a patent airway as confirmed with capnography, if moderate pressures were used.

Pulmonary aspiration is a feared complication in anesthesia practice. Even if it is a rare event it is the most common cause of anesthesia related death. There are two different types of pulmonary aspiration, macroaspirationwhere large amounts of gastric content are inhaled to the lungs, and the silent, often unnoticed, microaspiration, where small amounts of gastric or oropharyngeal contents are aspirated. Micro aspirations is much more common and can occur at any time during the perioperative period, presenting as postoperative pulmonary complications, often several days after the anesthesia procedure. Human physiology features multiple mechanisms of protection against pulmonary aspiration, including the esophageal sphincters that prevent gastric regurgitation and complex laryngeal reflex systems protecting the airway. An additional vital defense against pulmonary aspiration is an intact swallowing function, with dysphagia being the primary cause of aspiration pneumonia. Anesthetic agents affect these protective mechanisms to various extent. The aim of this thesis was to study the effects of sedative agents on swallowing function, and different ventilatory techniques during anesthesia induction in healthy volunteers. In study I, the use of positive end expiratory pressure during mask ventilation after anesthesia induction was studied in regard of risk of gastric insufflation. In study II and IV the pharmacological effects of the opioid remifentanil on swallowing function were studied. Study III was the first study on effects of dexmedetomidine on human swallowing physiology. The experiments in this thesis has led to a deeper understanding in how different anesthetic agents affects the physiological protective mechanisms against pulmonary aspiration, both during anesthesia induction and sedation. The findings may facilitate clinical decisions, leading to better risk management in terms of macroaspiration during anesthesia and sedation, and postoperative pulmonary

OBJECTIVES/HYPOTHESIS: Modulation of the pharyngeal swallow to bolus volume and viscosity is important for safe swallowing and is commonly studied using high-resolution pharyngeal manometry (HRPM). Use of unidirectional pressure sensor technology may, however, introduce variability in swallow measures and a fixed bolus administration protocol may induce time and order effects. We aimed to overcome these limitations and to investigate the effect of time by repeating randomized measurements using circumferential pressure sensor technology. STUDY DESIGN: Sub-set analysis of data from the placebo arm of a randomized, repeated measures trial. METHODS: HRPM with impedance was recorded using a solid-state catheter with 36 circumferential pressure sensors and 18 impedance segments straddling from hypopharynx to stomach. Testing included triplicates of 5, 10, and 20 ml thin liquid and 10 ml thick liquid boluses, the order of the thin liquid boluses was randomized. The swallow challenges were repeated approximately 10 minutes after finishing the baseline measurement. RESULTS: We included 19 healthy adults (10/9 male/female; age 24.5 ± 4.1 year). Intrabolus pressure, all upper esophageal sphincter (UES) opening and relaxation metrics, and flow timing metrics increased with larger volumes. A thicker viscosity decreased UES relaxation time, UES basal pressure, and flow timing metrics, whereas UES opening extent increased. Pre-swallow UES basal pressure and post-swallow UES contractile integral decreased over time. CONCLUSION: Using circumferential pressure sensor technology, the effects of volume and viscosity were largely consistent with previous reports. UES contractile pressures reduced over time. The growing body of literature offers a benchmark for recognizing aberrant pharyngo-esophageal motor responses. LEVEL OF EVIDENCE: 3 Laryngoscope, 2021., Funding agency:College of Medicine and Public Health, Flinders University

BACKGROUND: COVID-19 has a most variable prognosis. Several risk factors for an unfavourable outcome have been identified including extensive lung involvement on chest CT and high viral load estimated by RT-PCR cycle threshold (Ct) values. We investigated Ct value for outcome prediction, relation between Ct value and extent of lung involvement on chest CT and the combination of Ct value and chest CT lung involvement to predict outcome in COVID-19. METHODS: Population-based retrospective study on all patients (n = 286) hospitalised for COVID-19 in Örebro Region, Sweden, between 1 March and 31 August 2020. Nasopharyngeal samples and chest CT at hospital admission were evaluated in relation to outcome of COVID-19. RESULTS: Both Ct value and chest CT lung involvement were independently associated with risk for ICU admission or death. Lung involvement was superior as a single parameter, but addition of Ct value increased the prediction performance. Ct value was especially useful to identify patients with high risk for severe disease despite limited lung involvement. CONCLUSIONS: The addition of RT-PCR Ct value to the assessment of lung involvement on chest CT adds valuable prognostic information in COVID-19. We believe that this information can be used to support clinical decision-making when managing COVID-19 patients.

Background: Remifentanil impairs swallowing, and disturbed accommodation to bolus volume may be one of the underlying causes. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. Aims: To investigate if remifentanil-induced swallowing dysfunction is dependent on the bolus volume and whether the effect of remifentanil could be counteracted by methylnaltrexone, a peripherally acting opioid antagonist. Methods: Nineteen healthy volunteers were included in this double-blinded, randomized, placebo-controlled, crossover study. Study participants received target-controlled remifentanil infusions and placebo infusions in a randomized order. Methylnaltrexone was administered by intravenous injection of doses of 0.3 mg/kg. Recordings of pressure and impedance data were acquired using a combined manometry and impedance solid state catheter. Data was analyzed from three series of bolus swallows, baseline, during remifentanil exposure, and 15 min after methylnaltrexone. Results: Remifentanil induced significant effects on multiple pharyngeal and esophageal function parameters. No significant differences in remifentanil-induced swallowing dysfunction related to different bolus volumes were found. Pharyngeal effects of remifentanil were not significantly counteracted by methylnaltrexone, whereas on the distal esophageal level, effects on distension pressures were counteracted. Conclusions Changes in pharyngeal and esophageal pressure flow variables were consistent with previous results on remifentanil-induced swallowing dysfunction, and uniform across all bolus volumes. The effects of remifentanil on the pharyngeal level and on the proximal esophagus appear to be predominantly centrally mediated, whereas the effects of remifentanil on the distal esophagus may be mediated by both central and peripheral mechanisms. NEW & NOTEWORTHY: In this randomized controlled trial, we used the "Swallow Gateway" online, Funding agencies:Research Fund of the Örebro County CouncilALF research funding (Örebro University)University of TurkuNational Health and Medical Research Council of Australia

BACKGROUND: Chest CT is prognostic in Covid-19 but there is a lack of consensus on how to report the CT findings. A chest CT scoring system, ÖCoS, was implemented in clinical routine on 1 April 2020, in Örebro Region, Sweden. The ÖCoS-severity score measures the extent of lung involvement. The objective of the study was to evaluate the ÖCoS scores as predictors of the clinical course of Covid-19. METHODS: Population based study including data from all hospitalized patients with Covid-19 in Örebro Region during March to July 2020. We evaluated the correlations between CT scores at the time of admission to hospital and intensive care in relation to hospital and intensive care length of stay (LoS), intensive care admission and death. C-reactive protein and lymphocyte count were included as covariates in multivariate regression analyses. RESULTS: In 381 included patients, the ÖCoS-severity score at admission closely correlated to hospital length of stay, and intensive care admission or death. At admission to intensive care, the ÖCoS-severity score correlated with intensive care length of stay. The ÖCoS-severity score was superior to basic inflammatory biomarkers in predicting clinical outcomes. CONCLUSION: Chest CT visual scoring at admission to hospital predicted the clinical course of Covid-19 pneumonia., Funding Agency:Region Örebro län, Sweden OLL-878081

The usage of aortic balloon occlusion or resuscitative endovascular balloon occlusion of the aorta in trauma management for bleeding control is increasing rapidly as an alternative to thoracotomy and aortic clamping. Little is known about the effects of partial occlusion of the aorta as a bridge to definitive treatment, but one of its advantages may be limited visceral organ ischemia. We describe the first known case of partial aortic balloon occlusion in trauma for reaching a targeted systolic blood pressure, which was used as an adjunctive tool in trauma management and as a bridge to definitive treatment.