Traditional conscious sedation for endobronchial ultrasound procedures places patients at risk of desaturation, and high-flow nasal oxygen may reduce the risk. We designed a parallel-group randomised controlled trial of high-flow nasal oxygen at a flow rate of 30-70 l.min via nasal cannulae, compared with standard oxygen therapy at 10 l.min via a bite block in adults planned for conscious sedation for endobronchial ultrasound. The primary outcome was the proportion of patients experiencing desaturation (defined as SpO < 90%). Secondary outcomes included oxygen saturation after pre-oxygenation, lowest oxygen saturation during procedure, number of hypoxic episodes, duration of hypoxia, end-procedure end-tidal CO , satisfaction scores and complications. Thirty participants were allocated to each group. Baseline patient characteristics, procedure time and anaesthetic agents used were similar between the groups. Desaturation occurred in 4 out of 30 patients allocated to the high-flow nasal oxygen group, compared with 10 out of 30 allocated to the standard oxygenation group, a non-significant difference (p = 0.07) with intention to treat analysis. The difference was significant (p = 0.047) when using a per-protocol analysis. Oxygen saturation after pre-oxygenation and the lowest oxygen saturation during procedure were significantly higher in the high-flow nasal oxygen group compared with the standard oxygenation group; median (IQR [range] 100 (99-100 [93-100]) vs. 98 (97-99 [94-100]), p = 0.0001 and 97.5 (94-99 [77-100]) vs. 92 (88-95 [79-98]), p < 0.001, respectively. There were no differences in other secondary outcomes. Although high-flow nasal oxygen may prevent desaturation due to some causes, it does not protect against hypoxaemia in all circumstances.

This study explored the use of high-flow nasal oxygen (HFNO) in both pre-oxygenation and apnoeic oxygenation in adults who were intubated following a non-rapid sequence induction. Fifty patients were randomised to receive pre-oxygenation via a standard facemask or the Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) device. After five minutes of pre-oxygenation, induction and muscle relaxant agents were given. While waiting for complete paralysis, patients in the standard facemask group received bag-mask ventilation (BMV), whereas patients in the HFNO group received apnoeic oxygenation via the THRIVE device. Serial blood samples for arterial blood gas analysis were taken. Baseline patient and airway characteristics were similar. The median PaO 2 after pre-oxygenation was 357 (interquartile range [IQR] 324-450 [range 183-550]) mmHg in the facemask group, compared to 471 (IQR 429-516 [range 185-550]) mmHg in the HFNO group (P=0.01). The median arterial partial pressure of oxygen (PaO 2) in the HFNO group decreased after a period of apnoeic oxygenation, and was significantly lower when compared to patients who received BMV in facemask group. The arterial carbon dioxide partial pressure (PaCO 2) level after complete paralysis was significantly higher in the HFNO group when compared to the facemask group (median 52 [IQR 48-55 {range 40-65}] versus median 43 [IQR 40-48 {range 35-63}] mmHg, P=0.0005 and P=0.004 respectively). There were no differences in the time to muscle paralysis and time to intubation. Seven patients required use of airway adjuncts during BMV in the facemask group, compared to none in the HFNO group (P=0.004). No complications were observed in either group. HFNO produces a higher PaO 2 after pre-oxygenation and safe PaO 2 during intubation. However, the subsequent fall in PaO 2 and rise in PaCO 2 indicates that it is not as effective as BMV in maintaining oxygenation and ventilation following neuromuscular blockade.

The Ambu®AuraGain™ laryngeal mask (LM) (Ambu A/S, Ballerup, Denmark) is one of the few readily available second-generation supraglottic airway devices (SADs) that offer a conduit for fibreoptic-guided endotracheal intubation. We aimed to compare fibreoptic intubation through this device with the LMA® (laryngeal mask airway) Fastrach™ (Teleflex Medical, Co. Westmeath, Ireland), which has been a recommended dedicated rescue device for the management of the unanticipated difficult airway. This randomised controlled trial compared a previously described fibreoptic score in 116 patients with no known airway pathology, who had asleep fibreoptic endotracheal intubation via either the AuraGain LM or the LMA Fastrach. Time, ease and success rate of SAD and endotracheal tube (ETT) insertion and complications were recorded. The AuraGain LM demonstrated better laryngeal alignment with 29 out of 59 patients in the AuraGain LM (AG) group having a Grade 4 view (only vocal cords visible), compared to 20 out of 54 patients in the LMA Fastrach (FT) group (P=0.003). It allowed significantly quicker and easier ETT intubation when used as a conduit. The AuraGain LM was also quicker to insert compared to the Fastrach LMA. Similar rates of minor complications, such as sore throat and dysphonia occurred in both groups. Our study indicates that when used in patients with complete muscle relaxation and no known airway pathology, the AuraGain LM achieves better laryngeal alignment and quicker, easier and more successful fibreoptic-guided ETT intubation than the Fastrach LMA.

Objective This longitudinal study examined changes in psychological outcomes of perioperative frontline healthcare workers at one of Australia’s most COVID-19 affected hospitals, following the surge and decline of a pandemic wave. Method A single-centred longitudinal online survey was conducted between 26 May and 17 November 2020. Recruitment was via poster advertisement and email invitation. The survey was sent out every 4 weeks, resulting in seven time-points. Results In total, 385 survey results were analysed from 193 staff (about 64% response rate), 72 (37%) of whom completed the survey more than once. The prevalence of moderate-to-severe anxiety and depressive symptoms peaked at 27% and 25%, respectively, during the pandemic surge. Up to 35% displayed post-traumatic stress disorder (PTSD) symptoms. Although not statistically significant, the trend of depressive and PTSD symptoms worsened over time, especially among females and anaesthetic/surgical trainees, despite subsidence of the pandemic curve. Technicians and anaesthetic/scrub nurses were the at-risk groups with worst psychological outcomes. Conclusion We found persistent mental health impacts on frontline perioperative HCWs despite subsidence of the pandemic wave. Further research is needed to determine the extent and trajectory of such impacts with larger sample sizes to determine generalisability to frontline HCWs in general.

N95 particulate respirator masks are currently recommended for all healthcare workers who care for patients with suspected or confirmed coronavirus disease (COVID-19) when performing aerosol-generating procedures. The protection provided by N95 particulate respirator masks is dependent on the filter’s efficiency and seal quality. In this prospective randomised crossover study, we conducted the user seal check and the quantitative fit test on two readily available duckbill models of N95 masks, the Halyard Fluidshield® N95 (Halyard, Alpharetta, GA, USA) and the BSN Medical ProShield® N-95 (BSN Medical, Mount Waverley, Victoria) particulate respirator masks. We recruited a total of 96 anaesthetic staff, of whom 26% were of South-East Asian ethnicity. We found that both types of masks provided reasonably high fit test pass rates among our participants and there was no significant difference between the two brands (77% for the Fluidshield and 65% for the ProShield, P = 0.916). Ninety-two percent of the participants could find at least one well-fitted mask among these two types of masks. We also demonstrated that the user seal check had low accuracy and low concordance (kappa coefficient of 0.16 for the Fluidshield and 0.08 for the ProShield) when compared to the quantitative fit test, and hence was not a reliable method to test seal quality.