Warm humidified CO2 insufflation improves pericardial integrity for cardiac surgery: a randomized control study.

BACKGROUND: Flooding the surgical field with dry cold CO2 during open-chamber cardiac surgery has been used to mitigate air entrainment into the systemic circulation. However, exposing epithelial surfaces to cold, dry gas causes tissue desiccation. This randomized controlled study was designed to investigate whether the use of humidified warm CO2 insufflation into the cardiac cavity could reduce pericardial tissue damage and the incidence of micro-emboli when compared to dry cold CO2 insufflation. METHODS: Forty adult patients requiring elective open-chamber cardiac surgery were randomized to have either dry cold CO2 insufflation via a standard catheter or humidified warm CO2 insufflation via the HumiGard device (Fisher & Paykel Healthcare, Panmure, Auckland, New Zealand). The primary endpoint was biopsied pericardial tissue damage, assessed using electron microscopy. We assessed the percentage of microvilli and mesothelial damage, using a damage severity score (DSS) system. We compared the proportion of patients who had less damage, defined as DSS<2. Secondary endpoints included the severity of micro-emboli, by visual assessment of bubble load on transesophageal echocardiogram; lowest near infrared spectroscopy; total de-airing time; highest cardio-pulmonary bypass sweep speed; hospital length of stay and complications. RESULTS: A higher proportion of patients in the humidified warm CO2 group displayed conserved microvilli (47% vs. 11%, P=0.03) and preserved mesothelium (42% vs. 5%, P=0.02) compared to the control group. There were no differences in the secondary outcomes. CONCLUSIONS: Humidified warm CO2 insufflation significantly reduced pericardial epithelial damage when compared to dry cold CO2 insufflation in open-chamber cardiac surgery. Further studies are warranted to investigate its potential clinical benefits.

A longitudinal study of the psychological impact of the COVID-19 pandemic on frontline perioperative healthcare staff in an Australian tertiary public hospital.

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.

A randomised crossover study to compare the user seal check and quantitative fit test between two types of duckbill N95 particulate respirator masks: The Halyard Fluidshield® N95 and the BSN Medical ProShield® N-95 particulate respirator masks.

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.