Comparison of Different Methods For Effective Manual Chest Compression In Dental Chairs, During Cardiopulmonary Resuscitation (CPR): A Manikin Study

During cardiopulmonary resuscitation (CPR), almost commercially dental chairs lack sufficient stability to perform effective manual chest compression (MCC). In our previous study, our technique that stabilizing stool can significantly reduce vertical displacement in a dental chair’s backrest. This study demonstrates that the efficacy of different methods for stabilizing 3 types of dental chair with a flat or a severely curved backrest exterior for effective MCC. Vertical displacement of the dental chair’s backrest was recorded. The data was captured with three different stool positions (no stool, under MCC, under shoulders). Reduction ratios were calculated to evaluate the effectiveness of the stool positions. In all types of dental chair, the technique significantly reduced the vertical displacements of the backrest. The reduction ratio varied nearly 40% under the area for MCC and 65% under the shoulder with a severely curved backrest exterior. With a flat shape of dental chair, these ratios were around 90% versus without a stool. The technique is a firm support and reduce the displacement of any type of dental chair’s backrest for effective MCC.

Efficacy of SG Shield in reducing droplet contamination during collection of oropharyngeal swab culture specimens

Introduction: Oropharyngeal swabs for diagnosis of COVID-19 often induce violent coughing, which can disperse infectious droplets onto providers. Incorrectly doffing personal protective equipment (PPE) increases the risk of transmission. A cheap, single-use variation of the face shield invented by a Singaporean team, SG Shield, aims to reduce this risk. This manikin study aimed to study the efficacy of the SG Shield in combination with standard PPE. Methods: A person attired in full PPE whose face and chest was lined with grid paper stood in front of an airway manikin in an enclosed room. A small latex balloon containing ultraviolet fluorescent dye was placed in the oral cavity of the manikin and inflated until explosion to simulate a cough. Three study groups were tested: (a) control (no shield), (b) face shield and (c) SG Shield. The primary outcome was droplet dispersion, determined quantitatively by calculating the proportion of grid paper wall squares stained with fluorescent dye. The secondary outcome was the severity of provider contamination. Results: The SG Shield significantly reduced droplet dispersion to 0% compared to the controls (99.0%, p = 0.001). The face shield also significantly reduced droplet contamination but to a lesser extent (80.0%) compared to the control group (p = 0.001). Although the qualitative severity of droplet contamination was significantly lower in both groups compared to the controls, the face shield group had more contamination of the provider’s head and neck. Conclusion: The manikin study showed that the SG Shield significantly reduces droplet dispersion to the swab provider’s face and chest.

CPR with restricted patient access using alternative rescuer positions: a randomised cross-over manikin study simulating the CPR scenario after avalanche burial

Background The aim of this manikin study was to evaluate the quality of cardiopulmonary resuscitation (CPR) with restricted patient access during simulated avalanche rescue using over-the-head and straddle position as compared to standard position. Methods In this prospective, randomised cross-over study, 25 medical students (64% male, mean age 24) performed single-rescuer CPR with restricted patient access in over-the-head and straddle position using mouth-to-mouth ventilation or pocket mask ventilation. Chest compression depth, rate, hand position, recoil, compression/decompression ratio, hands-off times, tidal volume of ventilation and gastric insufflation were compared to CPR with unrestricted patient access in standard position. Results Only 28% of all tidal volumes conformed to the guidelines (400–800 ml), 59% were below 400 ml and 13% were above 800 ml. There was no significant difference in ventilation parameters when comparing standard to atypical rescuer positions. Participants performed sufficient chest compressions depth in 98.1%, a minimum rate in 94.7%, correct compression recoil in 43.8% and correct hand position in 97.3% with no difference between standard and atypical rescuer positions. In 36.9% hands-off times were longer than 9 s. Conclusions Efficacy of CPR from an atypical rescuer position with restricted patient access is comparable to CPR in standard rescuer position. Our data suggest to start basic life-support before complete extrication in order to reduce the duration of untreated cardiac arrest in avalanche rescue. Ventilation quality provided by lay rescuers may be a limiting factor in resuscitation situations where rescue ventilation is considered essential.

Macintosh laryngoscope and i-view™ and C-MAC® video laryngoscopes for tracheal intubation with an aerosol box: a randomized crossover manikin study

Background We tested the hypothesis that the C-MAC® video laryngoscope (C-MAC) with an external display is more useful than the disposable i-view™ video laryngoscope (i-view) with an integrated display or a Macintosh direct laryngoscope (Macintosh) for tracheal intubation with an aerosol box. Methods In this randomized, crossover manikin study, we recruited 37 medical personnel with > 2 years of dedicated anesthesia experience from five hospitals. After the three successful intubations within 60 s using each laryngoscope without a box, the participants performed tracheal intubation thrice with each laryngoscope with at least 2-h intervals in a determined order. The primary outcome was the intubation time. The secondary outcomes were success rate, Cormack-Lehane grade, and subjective difficulty scale score. Results Thirty-seven personnel (11 women and 26 men) with 12 [5–19] (median [interquartile range]) years of anesthesia and intensive care experience were enrolled. There was no significant difference in the intubation time: 30 [26–32] s for Macintosh, 29 [26–32] s for i-view, and 29 [25–31] s for C-MAC (P = 0.247). The success rate was 95–100%, without a significant difference (P = 0.135). The i-view and C-MAC exhibited superior Cormack-Lehane grades and lower subjective difficulty scale scores than the Macintosh; however, there were no differences between the i-view and C-MAC. Conclusions Rapid and highly successful tracheal intubation was possible with both Macintosh, i-view, and C-MAC on a normal airway manikin in an aerosol box. Improved Cormack-Lehane grade and the ease of performing the procedure may support the use of video laryngoscopes. Trial registration UMIN Clinical Trials Registry, UMIN000040269. Registered 30 April 2020.