LMA® protector™ in patients undergoing laparoscopic surgeries: a multicenter prospective observational study

Background Laryngeal masks airway (LMA) has been increasingly used in surgical patients. However, the use of LMA in laparoscopic surgeries remains controversial. The major concerns include the potential risk of esophageal regurgitation, aspiration, and difficulties to achieve effective ventilation. The aim of this study was to evaluate the safety and effectiveness of the LMA® Protector™ in patients undergoing laparoscopic surgery. Methods Patients aged 18 to 70 years, scheduled for laparoscopic surgeries were included. The insertion time, successful insertion rate, and oropharyngeal leak pressure were measured. Airway complications and airway manipulations during the procedure were documented. Effective ventilation rate was calculated. Visible bloodstains and reflux content in the drainage channel were documented after the removal of LMA® Protector™. Results Three hundred patients were enrolled. The insertion of LMA® Protector™ failed in seven patients resulting with a successful insertion rate of 97.7%. During the maintenance of anesthesia, airway manipulation was required in 19 patients (19/293, 6.48%), in three of whom the LMA was replaced with endotracheal intubation resulting with an effective ventilation rate of 96.7% (290/300). The oropharyngeal leak pressure was 30.18 ± 5.88 cmH2O. Seventy-five patients (25.86%) reported mild sore throat on the first day after surgery. Bloodstains on study devices were noticed in 58 patients (20%). Seventy-five patients (25.86%) reported mild sore throat on the first day after surgery. Gastric reflux was noticed in the drainage tube in 5 patients (1.72%) with no signs of aspiration in any of those patients. Conclusions The LMA® Protector™ was shown to be safe and effective in patients undergoing laparoscopic surgeries. Although minor complications that require no further treatment, no clinically diagnosed aspiration was noticed in our study. Gastric reflux was noticed in the drainage tube in five patients undergoing laparoscopic gynecology surgery. Further research is needed to verify whether LMA® Protector™ is suitable for procedures in Trendelenburg position or other situations that a high risk of gastroesophageal reflux exists. Trial registration The trial was registered at the Chinese Clinical Trial Registry (ChiCTR1800018300, date of registration: September 2018).

Abstract 13071: Supraglottic Airway Devices Are Associated With Asphyxial Physiology Upon Arrival for ECPR in Patients With Refractory OHCA Treated With Prolonged CPR

Introduction: Multiple clinical trials have failed to show significant differences in survival between use of endotracheal intubation (ETI) and supraglottic airway devices (SGA) in patients with out-of-hospital cardiac arrest (OHCA). However, treatment in these trials was limited to standard ACLS, which favors short duration of CPR. We sought to compare the physiological effect of ETI versus SGA use in patients treated with prolonged CPR and extracorporeal pulmonary resuscitation (ECPR) for refractory ventricular fibrillation/ventricular tachycardia (VT/VF) by the Minnesota Mobile Resuscitation Consortium (MMRC). Methods: Consecutive refractory VT/VF OHCA patients transported by the MMRC to the University of Minnesota for ECPR between 2015 and 2021 were included in this retrospective analysis. Patients were considered ineligible for ECPR if they failed specific arterial blood gas metabolic criteria (lactic acid >18 mmol/L, PaO2 <50 mmHg, and ETCO2 <10 mmHg). Metabolic parameters at presentation and survival were compared between patients receiving ETI and SGA. Results: Among 260 patients (58.0±11.8 years), 46.5% received ETI and 53.5% received SGA. During the index hospitalization, 78/260 (30%) achieved neurologically favorable survival. Compared to those receiving ETI, patients receiving SGA had lower PaO2 (116.8±118.7 versus 135.8±128.3 mmHg, p=0.03), higher PaCO2 (69.7±28.9 versus 60.7±25.6 mmHg, p=0.01), and lower pH (7.00±0.19 versus 7.06±0.21, p=0.008). Significantly more patients who received SGA had PaO2 <50mmHg (29.1% versus 16.9%, respectively; p=0.02) and ≥1 ECPR exclusion criteria (33.1% versus 20.7%, respectively; p=0.03). Among patients excluded for PaO2 <50 mmHg, the presenting PaO2 was 35.5±11.0 mmHg and the presenting PaCO2 was 94.5±26.2 mmHg, suggestive of absence of effective ventilation (asphyxia) at presentation. Survival with CPC 1-2 was 34.7% versus 25.9% for ETI versus SGA, respectively (p=0.12). Conclusion: Use of SGA, during prolonged CPR in refractory VT/VF OHCA, was associated with a significant increase in the proportion of patients presenting with significant hypoxemia and asphyxial physiology, thus increasing ineligibility for ECPR.

Abstract 11156: Thoracic Bioimpedance Ventilation Waveforms: Increased Amplitude with Larger Tidal Volume and Female Sex

Introduction: Effective ventilation during 30:2 CPR has been linked to improved outcomes, but definitive evidence is lacking. We developed a method to identify thoracic bioimpedance ventilation waveforms from defibrillator recordings. Hypothesis: Bioimpedance ventilation waveform amplitude is proportional to tidal volume. It is possible to identify a minimum amplitude for a valid ventilation waveform. Methods: To determine the relationship between tidal volume and bioimpedance waveform amplitude, we studied 26 healthy volunteers (12 males and 14 females). Volunteers breathed fixed positive pressure tidal volumes (250mL, 300 mL, 400 mL, 600 mL, and 800 mL) given by a Maquet SERVO-I ventilator (Getinge US Sales, Wayne, NJ, USA) through a mouthpiece while a Lifepak12 (Physio-Control, Redmond, WA) defibrillator recorded thoracic bioimpedance through electrode pads placed on the chest. We measured the impedance amplitudes of six breaths at each tidal volume and the weight and height of each volunteer. We set the minimum effective tidal volume at 250 mL. Results: For males and females, respectively, mean (±SD) was 180.1±8 cm vs. 164±3.5 cm, and mean weight was 85.6±9.6 kg vs. 58.3±8.6 kg. Median (IQR) bioimpedance amplitude for each tidal volume split by sex is shown in the Figure (Y-axis, 1 mm = 0.25 Ohm). Conclusion: Bioimpedance amplitude is proportional to tidal volume and also varies by height, weight, and sex. Sex may be a possible surrogate for height and weight. The minimum amplitude is 0.375 Ohm for a valid bioimpedance ventilation waveform.

Air, Air, Air: a champion midwife programme in Tanzania using HOT neonatal resuscitation—lessons learned

Background Tanzania has approximately 40 000 newborn deaths per year, with &gt;25% of these linked to intrapartum-related hypoxia. The Helping Babies Breathe© and Golden minute© (HBB©) programme was developed to teach skilled intervention for non-breathing neonates at birth. While Helping Babies Breathe© and Golden minute©, providing training in simulated bag and mask ventilation, is theoretically successful in the classroom, it often fails to transfer to clinical practice without further support. Furthermore, the proclivity of midwives to suction excessively as a first-line intervention is an ingrained behaviour that delays ventilation, contributing to very early neonatal deaths. Methods The ‘champion’ programme provided guided instruction during a real-life resuscitation. The site was Amana Hospital, Tanzania. The labour ward conducts 13 500 deliveries annually, most of which are managed by midwives. Brief mannikin simulation practice was held two to three times a week followed by bedside hands-on training (HOT) of bag and mask skills and problem solving while reinforcing the mantra of ‘air, air, air’ as the first-line intervention during a real-life emergency. Results Champion midwives (trainers) guided instructions given during a real emergency at the bedside caused learners beliefs to change. Trainees observed changes in baby skin colour and the onset of spontaneous breathing after effective ventilation. Conclusions Visible success during an actual real-life emergency created confidence, mastery and collective self-efficacy.

Suberosis at Public Health Unit (PHU) of Santa Maria da Feira/Arouca (F/A) (Portugal)

Introduction Santa Maria da Feira (SMF) is currently one of the largest producers of cork in Portugal. Suberosis is an occupational disease of workers in the cork processing industry, associated with repeated exposure to moldy cork dust, usually presenting itself as a disease of the pulmonary interstitium (Hypersensitivity Pneumonitis). This study aims to assess the impact of occupational health interventions on the cork industry, in terms of health promotion and risk prevention. Methods We assessed 10 different cork companies distributed in 10 parishes of SMF. Results With regard to health promotion, we highlight the development of healthy workplaces and the strong commitment to training health professionals with regard to the correct use of personal protective equipment (PPE). Regarding the prevention of risks, emphasis is placed on the two areas that imply greater professional risks: storage and the process of drilling and boring. The storage of cork is done most of the time in dark and humid places, providing ideal conditions for the development of mold and the process of drilling and boring exposes workers to large amounts of moldy cork dust. In these settings, investing in PPE namely protective gloves and mask, as well as collective prevention measures, namely effective ventilation systems and regular control of humidity conditions, are essential to health protection of workers. Conclusions SMF has a prevalence of Suberosis well above the national average. In order to respond to this issue, the cork industry must reinforce the investment in terms of PPE, with the use of uniform, cuffs, safety shoes and visor, variable with the specific production process. In terms of collective protection, the signaling of the main hazards and the information available in the workstations regarding mandatory/recommended PPE, isolation of the areas with the most dangerous tasks as well as the maximum possible turnover between tasks are essential in terms of Occupational Health. Key messages Suberosis is an occupational disease of workers in the cork industry, associated with repeated exposure to moldy cork dust, usually presenting itself as a disease of the pulmonary interstitium. The development of healthy workplaces, the correct use of PPE and the investment in effective ventilation systems and control of humidity, are essential to health protection of cork workers.

Experimental investigation of combinational fans influencing on the effective ventilation in an undersea metro interval tunnel

Based on the metro undersea interval from Wawuzhuang Station to Guizhou Road Station of Qingdao Metro Line 1, a physical model system is built for the sake to further study the Ventilation and Smoke Exhaust System (VSES) of this interval tunnel. In the VSES experimental system, it gains data of variable frequencies inputting to fans, consumed-power values of fans, velocities in carriageways and SEDs (Smoke Exhaust Ducts), static pressure in carriageways under the conditions of the TP (Two Pressing-in) and TP+OE (Two Pressing-in + One Extracted-out) combinations of fans. The experimental data are shown that the static pressure field in horizontal carriageways has a symmetrical distribution, whose symmetry axis is as the plane of a smoke ceiling, whether TP or TP+OE. Under the TP+OE, the velocities in SEDs and carriageways are influenced dominantly by an extracted-out fan; two pressing-in fans of the TP combination influence mainly those velocities. A velocity is capable to dilute and coerce a smog flue. The pushing force of the smog flue is supplied by a pressing-in fan with consumed-power values, and another pressing-in fan with the lower values prevents this flue from another carriageway; furthermore, the pulling force of this flue is supplied by an extracted-out fan with the largest consumed-power values. The ratio of the total values of fans to the discharged volume flow rates in both SEDs is proposed as a new criterion, which can quantify VSES performance and is equivalent to airflow pressure; it is shown that the VSES performance of the TP+OE combination promotes gradually and becomes superior to one of the TP. Finally, it is advisory that the TP+OE should be a preferential combination of fans in designs and engineering situ management of extra length and large section tunnel ventilation.

The risk of indoor sports and culture events for the transmission of COVID-19

Nearly all mass gathering events worldwide were banned at the beginning of the COVID-19 pandemic, as they were suspected of presenting a considerable risk for the transmission of SARS-CoV-2. We investigated the risk of transmitting SARS-CoV-2 by droplets and aerosols during an experimental indoor mass gathering event under three different hygiene practices, and used the data in a simulation study to estimate the resulting burden of disease under conditions of controlled epidemics. Our results show that the mean number of measured direct contacts per visitor was nine persons and this can be reduced substantially by appropriate hygiene practices. A comparison of two versions of ventilation with different air exchange rates and different airflows found that the system which performed worst allowed a ten-fold increase in the number of individuals exposed to infectious aerosols. The overall burden of infections resulting from indoor mass gatherings depends largely on the quality of the ventilation system and the hygiene practices. Presuming an effective ventilation system, indoor mass gathering events with suitable hygiene practices have a very small, if any, effect on epidemic spread.

Application of Portable Air Purifiers for Mitigating COVID-19 in Large Public Spaces

This study investigated, using validated computational fluid dynamics techniques, the actual performance of portable air purifiers for reducing the infection risks of airborne respiratory diseases such as COVID-19, by properly installing air purifiers in complicated large public spaces of primary concern, such as restaurants and ballrooms. The research results reveal that portable air purifiers with HEPA filtration provide an effective solution to help mitigate virus-carrying particles/droplets in large spaces where the central air conditioning system with HEPA filtration may not provide adequate dilution and/or effective ventilation. Deploying portable air purifier changes the local flow directions, and thus, reduces the cross-table airflows that may enhance the possibility of cross-infection. A field experiment was further conducted in a restaurant and a ballroom to verify the on-site performance. This study indicates that each space is unique in furniture, occupant and system layouts and capacities, and thus, requires individualized investigation of appropriate purifier number, capacities, and locations. Flexible solutions such as portable air purifiers are important and low-cost supplements to more elaborate solutions installed in central air systems.