Anaesthesiology

Treating patients across European Union borders: An international survey in light of the coronavirus disease-19 pandemic BACKGROUND In light of the coronavirus disease-2019 (COVID-19) pandemic, how resources are managed and the critically ill are allocated must be reviewed. Although ethical recommendations have been published, strategies for dealing with overcapacity of critical care resources have so far not been addressed. OBJECTIVES Assess expert opinion for allocation preferences regarding the growing imbalance between supply and demand for medical resources. DESIGN A 10-item questionnaire was developed and sent to the most prominent members of the European Society of Anaesthesiology and Intensive Care (ESAIC). SETTING Survey via a web-based platform. PATIENTS Respondents were members of the National Anaesthesiologists Societies Committee and Council Members of the ESAIC; 74 of 80 (92.5%), responded to the survey. MEASUREMENTS AND MAIN RESULTS Responses were analysed thematically. The majority of respondents (83.8%), indicated that resources for COVID-19 were available at the time of the survey. Of the representatives of the ESAIC governing bodies, 58.9% favoured an allocation of excess critical care capacity: 69% wished to make them available to supraregional patients, whereas 30.9% preferred to keep the resources available for the local population. Regarding the type of distribution of resources, 35.3% preferred to make critical care available, 32.4% favoured the allocation of medical equipment and 32.4% wished to support both options. The majority (59.5%) supported the implementation of a central European institution to manage such resource allocation. CONCLUSION Experts in critical care support the allocation of resources from centres with overcapacity. The results indicate the need for centrally administered allocation mechanisms that are not based on ethically disputable triage systems. It seems, therefore, that there is wide acceptance and solidarity among the European anaesthesiological community that local medical and human pressure should be relieved during a pandemic by implementing national and international re-allocation strategies among healthcare providers and healthcare systems. Correspondence to Elisabeth H. Adam, MD, MHBA, Department of Anaesthesia, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Theodor-Stern Kai 7, 60590 Frankfurt, Germany Tel: +49 69 6301 5868; fax: +49 69 6301 7695; e-mail: elisabeth.adam@kgu.de Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.ejanaesthesiology.com). This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0 © 2020 European Society of Anaesthesiology

Chronic stress indicated by hair cortisol concentration in anaesthesiologists and its relationship to work experience and emotional intelligence: A cross-sectional biomarker and survey study BACKGROUND Anaesthesia is a stressful medical specialty. The reaction to stress is constituted by behavioural, psychological and physiological components. Chronic physiological stress can have negative consequences for health. OBJECTIVES First, we hypothesised that chronic physiological stress is higher for both beginning and late-career consultant anaesthesiologists. Second, we hypothesised that individuals high in emotional intelligence endure lower physiological stress. DESIGN Cross-sectional biomarker and survey study. SETTING Participants were recruited during the May 2019 annual meeting of the Dutch Anaesthesia Society. PARTICIPANTS Of the 1348 colleagues who attended the meeting, 184 (70 male/114 female) participated in the study. Of the study participants, 123 (67%) were consultant anaesthesiologists (52 male/71 female) and 61 (33%) were resident anaesthesiologists (18 male/43 female). Exclusion criteria were endocrine disorders and not having enough hair. Also, experience of a recent major life event led to exclusion from analysis of our hypotheses. MAIN OUTCOME MEASURES Chronic physiological stress was measured by hair cortisol concentration. Emotional intelligence was assessed using a validated Dutch version of the Trait Emotional Intelligence Questionnaire. As secondary measures, psychological sources of stress were assessed using validated Dutch versions of the home-work interference (SWING) and the effort-reward imbalance questionnaires. RESULTS In support of Hypothesis 1, hair cortisol concentration was highest among early and late-career consultant anaesthesiologists (quadratic effect: b = 45.5, SE = 16.1, t = 2.8, P = 0.006, R2 = 0.14). This nonlinear pattern was not mirrored by self-reported sources of psychological stress. Our results did not support Hypothesis 2; we found no evidence for a relationship between emotional intelligence and physiological stress. CONCLUSION In the early and later phases of an anaesthesiologist's career, physiological chronic stress is higher than in the middle of the career. However, this physiological response could not be explained from known sources of psychological stress. We discuss these findings against the background of key differences between physiological and psychological stress. Correspondence to Raymond A.B. van der Wal, Radboud University Nijmegen Medical Center, Department of Anaesthesiology, Pain and Palliative Medicine, Internal postal code 717, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands Tel: +31 24 361 4406; e-mail: Raymond.vanderwal@radboudumc.nl Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.ejanaesthesiology.com). © 2020 European Society of Anaesthesiology

Hand or foot train-of-four tests and surgical site muscle relaxation assessed with multiple motor evoked potentials: A prospective observational study BACKGROUND Intra-operative muscle relaxation is often required in orthopaedic surgery and the hand train-of-four (TOF) test is usually used for its quantification. However, even though full muscle relaxation is claimed by anaesthesiologists based on a TOF count of zero, surgeons observe residual muscle activity. OBJECTIVE The aim of the study was to assess if hand or foot TOF adequately represents intra-operative muscle relaxation compared with multiple motor evoked potentials. DESIGN Prospective observational study. SETTING A single-centre study performed between February 2016 and December 2018 at the Balgrist University Hospital, Zurich, Switzerland. PATIENTS Twenty patients scheduled for elective lumbar spinal fusion were prospectively enrolled in this study after giving written informed consent. INTERVENTIONS To assess neuromuscular blockade (NMB) with the intermediate duration nondepolarising neuromuscular blocking agent rocuronium, hand TOF (adductor pollicis) and foot TOF (flexor hallucis brevis) monitoring, and muscle motor evoked potentials (MMEPs) from the upper and lower extremities were assessed prior to surgery under general anaesthesia. Following baseline measurements, muscle relaxation was performed with rocuronium until the spinal surgeon observed sufficient relaxation for surgical intervention. At this timepoint, NMB was assessed by TOF and MMEP. MAIN OUTCOME MEASURES The primary outcome was to determine the different effect of rocuronium on muscle relaxation comparing hand and foot TOF with the paraspinal musculature assessed by MMEP. RESULTS Hand TOF was more resistant to NMB and had a shorter recovery time than foot TOF. When comparing MMEPs, muscle relaxation occurred first in the hip abductors, and the paraspinal and deltoid muscles. The most resistant muscle to NMB was the abductor digiti minimi. Direct comparison showed that repetitive MMEPs simultaneously recorded from various muscles at the upper and lower extremities and from paraspinal muscles reflect muscle relaxation similar to TOF testing. CONCLUSION Hand TOF is superior to foot TOF in assessing muscle relaxation during spinal surgery. Hand TOF adequately represents the degree of muscle relaxation not only for the paraspinal muscles but also for all orthopaedic surgical sites where NMB is crucial for good surgical conditions. TRIAL REGISTRATION clinicalTrials.gov (NCT03318718). Correspondence to Michael Betz, MD, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008 Zurich, Switzerland Tel: +41 44 386 1600; fax: +41 44 386 1269; e-mail: Michael.betz@balgrist.ch This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0 © 2020 European Society of Anaesthesiology

Effect of dexmedetomidine on Nociception Level Index-guided remifentanil antinociception: A randomised controlled trial BACKGROUND The effect of dexmedetomidine on Nociception Level Index (Medasense, Israel) antinociception to reduce intra-operative opioid requirements has not been previously investigated. OBJECTIVE We aimed to determine if low-dose dexmedetomidine would reduce remifentanil requirements during Nociception Level Index-guided antinociception without increasing complications associated with dexmedetomidine. DESIGN Double-blind randomised controlled trial. SETTING Two university teaching hospitals in Brussels, Belgium. PATIENTS American Society of Anesthesiologists 1 and 2 patients (n = 58) undergoing maxillofacial or cervicofacial surgery under propofol--remifentanil target-controlled infusion anaesthesia. INTERVENTIONS A 30 min infusion of dexmedetomidine, or equal volume of 0.9% NaCl, was infused at 1.2 μg kg−1 h−1 immediately preceding induction and then decreased to 0.6 μg kg−1 h−1 until 30 min before ending surgery. Nociception Level Index and frontal electroencephalogram guided the remifentanil and propofol infusions, respectively. MAIN OUTCOMES The primary outcome was the remifentanil requirement. Other outcomes included the propofol requirement, cardiovascular status and postoperative outcome. RESULTS Mean ± SD remifentanil (3.96 ± 1.95 vs. 4.42 ± 2.04 ng ml−1; P = 0.0024) and propofol (2.78 ± 1.36 vs. 3.06 ± 1.29 μg ml−1; P = 0.0046) TCI effect site concentrations were lower in the dexmedetomidine group at 30 min postincision and remained lower throughout surgery. When remifentanil (0.133 ± 0.085 vs. 0.198 ± 0.086 μg kg−1 min−1; P = 0.0074) and propofol (5.7 ± 2.72 vs. 7.4 ± 2.80 mg kg−1 h−1; P = 0.0228) requirements are represented as infusion rates, this effect became statistically significant at 2 h postincision. CONCLUSION In ASA 1 and 2 patients receiving Nociception Level Index-guided antinociception, dexmedetomidine decreases intra-operative remifentanil requirements. Combined frontal electroencephalogram and Nociception Level Index monitoring can measure dexmedetomidine's hypnotic and opioid-sparing effects during remifentanil-propofol target-controlled infusion anaesthesia. TRIAL REGISTRATIONS Clinicaltrials.gov: NCT03912740, EudraCT: 2018-004512-22. Correspondence to Sean Coeckelenbergh, Department of Anaesthesiology, Erasme University Hospital, Université Libre de Bruxelles, Rue Lennik 808, 1070 Brussels, Belgium Tel: +32 25 55 39 19; e-mail: sean.coeckelenbergh@ulb.be Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.ejanaesthesiology.com). © 2020 European Society of Anaesthesiology

Pectoral nerve blocks for breast surgery: A meta-analysis BACKGROUND Pectoral nerve blocks (PECS block) might be an interesting new regional anaesthetic technique in patients undergoing breast surgery. OBJECTIVE The aim of this meta-analysis was to investigate postoperative pain outcomes and adverse events of a PECS block compared with no treatment, sham treatment or other regional anaesthetic techniques in women undergoing breast surgery. DESIGN We performed a systematic review of randomised controlled trials (RCT) with meta-analysis and risk of bias assessment. DATA SOURCES The databases MEDLINE, CENTRAL (until December 2019) and clinicaltrials.gov were systematically searched. ELIGIBILITY CRITERIA All RCTs investigating the efficacy and adverse events of PECS compared with sham treatment, no treatment or other regional anaesthetic techniques in women undergoing breast surgery with general anaesthesia were included. RESULTS A total of 24 RCTs (1565 patients) were included. PECS (compared with no treatment) block might reduce pain at rest [mean difference −1.14, 95% confidence interval (CI), −2.1 to −0.18, moderate quality evidence] but we are uncertain regarding the effect on pain during movement at 24 h after surgery (mean difference −1.79, 95% CI, −3.5 to −0.08, very low-quality evidence). We are also uncertain about the effect of PECS block on pain at rest at 24 h compared with sham block (mean difference −0.83, 95% CI, −1.80 to 0.14) or compared with paravertebral block (PVB) (mean difference −0.18, 95% CI, −1.0 to 0.65), both with very low-quality evidence. PECS block may have no effect on pain on movement at 24 h after surgery compared with PVB block (mean difference −0.56, 95% CI, −1.53 to 0.41, low-quality evidence). Block-related complications were generally poorly reported. CONCLUSION There is moderate quality evidence that PECS block compared with no treatment reduces postoperative pain intensity at rest. The observed results were less pronounced if patients received a sham block. Furthermore, PECS blocks might be equally effective as PVBs. Due to mostly low-quality or very low-quality evidence level, further research is warranted. PROTOCOL REGISTRATION CRD42019126733. Correspondence to Priv.-Doz. Dr. med. Alexander Schnabel, Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital of Muenster, Albert-Schweitzer Campus 1A, 48149 Muenster, Germany. Tel: +49 251 47255; e-mail: alexander.schnabel@ukmuenster.de Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.ejanaesthesiology.com). © 2020 European Society of Anaesthesiology

Efficacy of intra-operative administration of iron isomaltoside for preventing postoperative anaemia after total knee arthroplasty: A randomised controlled trial BACKGROUND Postoperative anaemia is common after total knee arthroplasty (TKA). Emerging evidence shows the beneficial effects of peri-operative iron supplementation in patients at risk of postoperative anaemia. OBJECTIVE To evaluate the efficacy of intra-operative administration of iron isomaltoside for the prevention of postoperative anaemia in patients undergoing TKA. DESIGN Randomised, controlled, double-blind, parallel-group study. SETTING A tertiary care teaching hospital; between 29 March 2018 and 16 April 2019. PATIENTS Eighty-nine patients scheduled for unilateral TKA were included. INTERVENTION Iron isomaltoside or placebo were administered intravenously over 30 min during surgical wound closure. MAIN OUTCOME MEASURES The primary outcome measure was the incidence of anaemia at 30 days after TKA: anaemia was defined as haemoglobin less than 12 g dl−1 for female and less than 13 g dl−1 for male. RESULTS In total, 89 patients were included in the final analysis (44 in the treatment group; 45 in the control group). The administered dose of iron isomaltoside in the treatment group was 1136 ± 225 mg. The incidence of anaemia at 30 days after TKA was significantly lower in the treatment group (34.1%, 15/44) than that in the control group (62.2%, 28/45): relative risk 0.55 (95% confidence interval, 0.34 to 0.88), P = 0.008. Haemoglobin concentration, serum ferritin concentrations, and transferrin saturation were also significantly higher in the treatment group at 30 days after TKA. CONCLUSION The intra-operative administration of iron isomaltoside effectively prevents postoperative anaemia in patients undergoing TKA, and thus it can be included in patient blood management protocols for reducing postoperative anaemia in these population. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT03470649. Correspondence to Jin-Tae Kim, Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Daehak-ro 101, Jongno-gu, Seoul 03080, South Korea Tel: +82 2 2072 3295; e-mail: jintae73@gmail.com Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.ejanaesthesiology.com). © 2020 European Society of Anaesthesiology

The efficacy of high flow nasal oxygenation for maintaining maternal oxygenation during rapid sequence induction in pregnancy: A prospective randomised clinical trial BACKGROUND High-flow nasal oxygenation (HFNO) for pre-oxygenation in rapid sequence induction (RSI) has only been assessed in volunteer parturients without intubation. OBJECTIVES To evaluate the efficacy of HFNO in comparison with the conventional facemask for oxygenation during RSI for caesarean section under general anaesthesia. SETTING Operating room in a tertiary hospital. DESIGN Prospective randomised, controlled study. PARTICIPANTS Thirty-four healthy parturients undergoing general anaesthesia for caesarean section. INTERVENTIONS Parturients were randomly assigned to HFNO or standard facemask (SFM) group. MAIN OUTCOME MEASURES The primary outcome measure was the PaO2 immediately after intubation. Secondary outcomes included lowest saturation throughout the intubation procedure, end-tidal oxygen concentration (EtO2) on commencing ventilation, blood gas analysis (pH, PaCO2), fetal outcomes and intubation-related adverse events. RESULTS PaO2 in the HFNO group was significantly higher than that in SFM group (441.41 ± 46.73 mmHg versus 328.71 ± 72.80 mmHg, P < 0.0001). The EtO2 concentration in the HFNO group was higher than that in the SFM group (86.71 ± 4.12% versus 76.94 ± 7.74%, P < 0.0001). Compared to baseline, PaCO2 immediately after intubation also increased significantly in both groups (HFNO group: 30.87 ± 2.50 mmHg versus 38.28 ± 3.18 mmHg; SFM group: 29.82 ± 2.57 mmHg versus 38.05 ± 5.76 mmHg, P < 0.0001), but there was no difference in PaCO2 between the two groups. There was no difference in lowest saturation, intubation times, duration of apnoea, pH value or fetal outcomes. CONCLUSIONS Compared with SFM, HFNO provided a higher PaO2 and EtO2 immediately after intubation in parturients. HFNO is safe as a method of oxygenation during RSI in parturients undergoing general anaesthesia for caesarean section. TRIAL REGISTRATION Clinical trial ChiCTR1900023121. Correspondence to Zhiqiang Liu, Department of Anaesthesiology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, 2699 Gaoke West Road, Shanghai 201204, P.R. China Tel: +021 20261023; e-mail: drliuzhiqiang@163.com © 2020 European Society of Anaesthesiology

Effects on BMI and regional prevalence of malignant hyperthermia pathogenic ryanodine receptor type 1 sequence variants in Switzerland: A retrospective cohort analysis BACKGROUND Ryanodine receptor type 1 (RYR1) sequence variants are pathogenic for malignant hyperthermia. Variant carriers have a subtle increase in resting myoplasmic calcium concentration compared with nonaffected individuals, but whether this has metabolic effects in daily life is unknown. OBJECTIVES We analysed the potential effect of malignant hyperthermia-pathogenic RYR1 sequence variants on BMI as a single factor. Due to the heterogeneity of genetic variants predisposing to malignant hyperthermia, and to incomplete information about their regional distribution, we describe the prevalence of RYR1 variants in our population. DESIGN A retrospective cohort study. SETTING A single University hospital. PATIENTS Patients from malignant hyperthermia families with pathogenic RYR1 sequence variants were selected if BMI was available. OUTCOME MEASURES BMI values were compared amongst malignant hyperthermia susceptible (MHS) and malignant hyperthermia-negative individuals using hierarchical multivariable analyses adjusted for age and sex and considering family clustering. Variant prevalence was calculated. RESULTS The study included 281 individuals from 42 unrelated malignant hyperthermia families, 109 of whom were MHS and carriers of the familial RYR1 sequence variants. Median [IQR] BMI in MHS individuals with pathogenic RYR1 variants was 22.5 kg m−2 [21.3 to 25.6 kg m−2]. In malignant hyperthermia-negative individuals without variants, median BMI was 23.4 kg m−2 [21.0 to 26.3 kg m−2]. Using multivariable regression adjusted for age and sex, the mean difference was −0.73 (95% CI −1.51 to 0.05). No carrier of a pathogenic RYR1 sequence variant was found to have BMI more than 30 kg m−2. Only 10 RYR1 variants from the list of the European MH Group were found in our cohort, the most common being p.Val2168Met (39% of families), p.Arg2336His (24%) and p.Arg614Cys (12%). CONCLUSION The observed tendency towards lower BMI values in carriers of malignant hyperthermia-pathogenic RYR1 sequence variants points to a possible protective effect on obesity. This study confirms regional differences of the prevalence of malignant hyperthermia-pathogenic RYR1 sequence variants, with just three variants covering 75% of Swiss MHS families. TRIAL REGISTRATION This manuscript is based on a retrospective analysis. Correspondence to Oliver Bandschapp, MD, Department of Anesthesia, Interdisciplinary Intermediate Care, Prehospital Emergency Medicine and Pain Therapy, University Hospital, University of Basel, Spitalstrasse 21, 4031 Basel, Switzerland Tel: +41 61 265 72 54; e-mail: oliver.bandschapp@usb.ch © 2020 European Society of Anaesthesiology

Effect of positive end-expiratory pressure during anaesthesia induction on nonhypoxic apnoea time in infants: A randomised controlled trial BACKGROUND Hypoxaemia occurs frequently in infants during anaesthetic induction. OBJECTIVE We evaluated the effect of positive end-expiratory pressure during anaesthesia induction on nonhypoxic apnoea time in infants. DESIGN Randomised controlled trial. SETTING Tertiary care children's hospital, single centre, from November 2018 to October 2019. PATIENTS We included patients under 1 year of age receiving general anaesthesia. INTERVENTION We assigned infants to a 7 cmH2O or 0 cmH2O positive end-expiratory pressure group. Anaesthesia was induced with 0.02 mg kg−1 atropine, 5 mg kg−1 thiopental sodium and 3 to 5% sevoflurane, and neuromuscular blockade with 0.6 mg kg−1 rocuronium. Thereafter, 100% oxygen was provided via face mask with volume-controlled ventilation of 6 ml kg−1 tidal volume, and either 7 cmH2O or no positive end-expiratory pressure. After 3 min of ventilation, the infants' trachea was intubated but disconnected from the breathing circuit, and ventilation resumed when pulse oximetry reached 95%. MAIN OUTCOME MEASURE The primary outcome was nonhypoxic apnoea time defined as the time from cessation of ventilation to a pulse oximeter reading of 95%, whereas the secondary outcome was the incidence of significant atelectasis (consolidation score ≥2) assessed by lung ultrasound. RESULTS Sixty patients were included in the final analysis. Apnoea time in the 7 cmH2O positive end-expiratory pressure group (105.2 s) increased compared with that in the control group (92.1 s) (P = 0.011, mean difference 13.0 s, 95% CI, 3.1 to 22.9 s). Significant atelectasis was observed in all patients without positive end-expiratory pressure and 66.7% of those with 7 cmH2O positive end-expiratory pressure (P = 0.019, 95% CI, 1.7 to 563.1, odds ratio 31.2). CONCLUSION Positive end-expiratory pressure during anaesthesia induction with face mask ventilation increased nonhypoxic apnoea time in infants. CLINICAL TRIAL REGISTRATION www.clinicaltrials.gov, NCT03540940. Correspondence to Hee-Soo Kim, MD, PhD, Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, #101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea Tel: + 82 2 2072 3659; fax: +82 2 747 8412; e-mail: dami0605@snu.ac.kr © 2020 European Society of Anaesthesiology

Supraglottic jet oxygenation and ventilation reduces desaturation during bronchoscopy under moderate to deep sedation with propofol and remifentanil: A randomised controlled clinical trial BACKGROUND Hypoxaemia is frequently seen during flexible bronchoscopies that are done with a nasal approach under the traditional sedation with propofol. This study investigated the potential benefits of supraglottic jet oxygenation and ventilation (SJOV) using the Wei nasal jet tube (WNJ) in reducing hypoxaemia in patients undergoing bronchoscopy under moderate to deep intravenous sedation using a propofol, lidocaine and remifentanil cocktail. OBJECTIVES Our primary objective was to evaluate the efficacy and complications of SJOV via the WNJ during flexible bronchoscopy under moderate to heavy sedation with propofol and remifentanil. DESIGN A randomised controlled clinical trial. SETTING The 180th Hospital of People's Liberation Army, Quanzhou, China, from 1 June to 1 November 2019. PATIENTS A total of 280 patients aged ≥18 years with American Society of Anesthesiologists' physical status 1 to 3 undergoing flexible bronchoscopy were studied. INTERVENTIONS Patients were assigned randomly into one of two groups, a nasal cannula oxygenation (NCO) group (n = 140) using a nasal cannula to deliver oxygen (4 l min−1) or the SJOV group (n = 140) using a WNJ connected to a manual jet ventilator to provide SJOV at a driving pressure of 103 kPa, respiratory rate 20 min−1, FIO2 1.0 and inspiratory:expiratory (I:E) ratio 1:2. MAIN OUTCOME MEASURES The primary outcome was an incidence of desaturation (defined as SpO2 < 90%) during the procedure. Other adverse events related to the sedation or SJOV were also recorded. RESULTS Compared with the NCO group, the incidence of desaturation in the SJOV group was lower (NCO 37.0% vs. SJOV 13.1%) (P < 0.001). Patients in the SJOV group had a higher incidence of a dry mouth at 1 min (13.1% vs. 1.5%, P < 0.001) than at 30 min (1.5% vs. 0%, P = 0.159) or at 24 h (0% vs. 0%). There was no significant difference between the groups in respect of sore throat, subcutaneous emphysema or nasal bleeding. CONCLUSIONS SJOV via a WNJ during flexible bronchoscopy under moderate to deep sedation with propofol and remifentanil significantly reduces the incidence of desaturation when compared with regular oxygen supplementation via a nasal cannula. Patients in the SJOV group had an increased incidence of transient dry mouth. TRIAL REGISTRATION Registered at www.chictr.org.cn (ChiCTR1900023514). Correspondence to Ping Xie, Department of Anesthesiology, 180th Hospital of PLA, Quanzhou 362000, China. E-mail: 21621853@qq.com This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0 © 2020 European Society of Anaesthesiology

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Medicine by Alexandros G. Sfakianakis,Anapafseos 5 Agios Nikolaos 72100 Crete Greece,00302841026182,00306932607174,alsfakia@gmail.com,

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