Abstract 13110: Novel Application of Thoracic Impedance to Characterize Ventilations During Cardiopulmonary Resuscitation in the Pragmatic Airway Resuscitation Trial

Introduction: Controlled ventilation is important in OHCA resuscitation, but there are few validated methods for accurate detection of ventilations. We sought to utilize changes in thoracic impedance (TI) to characterize resuscitation ventilations in the Pragmatic Airway Resuscitation Trial (PART). Methods: We analyzed CPR process files collected from adult OHCA enrolled in PART. We limited the analysis to cases with simultaneous capnography ventilation recordings at the Dallas-Ft Worth site. We identified ventilation waveforms in the thoracic impedance signal by applying automated signal processing with adaptive filtering techniques to remove overlying artifacts from chest compressions. We correlated detected ventilations with the end-tidal capnography signal. We determined the amplitudes (Ai, Ae) and durations (Di, De) of both insufflation and exhalation phases of the ventilation impedance signal (Figure 1). We compared differences between laryngeal tube (LT) and endotracheal intubation (ETI) airway management during mechanical or manual chest compressions using Mann-Whitney U-test. Results: We included 303 CPR process cases in the analysis; 209 manual (77 ETI, 132 LT), 94 mechanical (41 ETI, 53 LT). Ventilation Ai and Ae were higher for ETI than LT in both manual (ETI: Ai 0.71Ω, Ae 0.70Ω vs LT: Ai 0.46Ω Ae 0.45Ω, p<0.01 respectively) and mechanical chest compressions (ETI: Ai 1.22Ω, Ae 1.14Ω VS LT: Ai 0.74Ω, Ae 0.68Ω, p<0.01 respectively). Ventilations per minute, duration of TI amplitude insufflation and exhalation did not differ among groups. Conclusion: Compared with LT, ETI thoracic impedance ventilation insufflation and exhalation amplitude were higher while duration did not differ. TI may provide a novel approach to characterizing ventilation during OHCA.

Abstract 10874: Evaluation of Intensive Care Unit and Ventilator-free Days as Alternative Outcomes in Out-of-Hospital Cardiac Arrest Trials

Objective: Compared with traditional out-of-hospital cardiac arrest (OHCA) trial outcomes such as hospital survival, alternative outcomes such as intensive care unit-free (IFD) and ventilator-free days (VFD) have potential advantages including requiring smaller sample sizes to detect significant differences. Few studies have evaluated these outcomes in OHCA. We sought to evaluate the utility and validity of IFD and VFD as candidate outcomes for OHCA trials. Methods: We analyzed data from the Pragmatic Airway Resuscitation Trial (PART), which tested laryngeal tube (LT) vs. endotracheal intubation (ETI) airway strategies in adult OHCA. We defined IFD as the number of days alive and permanently out of ICU during the first 30 days after the OHCA event. We examined IFD distribution and correlation with Modified Rankin Scale (MRS). To test associations with trial interventions, we applied a range of analytic strategies, including modeling IFD as continuous (Generalized Estimating Equations - GEE), non-parametric (Wilcoxon Rank-Sum test - WRS) and count (zero-inflated negative binomial regression - ZINB) data. We also modeled time-to-ICU discharge using a survival model with death as a competing risk. We repeated the analysis assessing VFD. Results: IFD was available for 2,898 of 3,004 patients. IFD was skewed and J-shaped; 91% IFD=0 and 5.3% IFD≥22. Mean (±SD) IFD was 2.0±6.6 days; 21.2±7.5 days for survivors. IFD varied by intervention (LT 2.4±7.2, ETI 1.6±5.8 days). IFD and VFD strongly correlated with MRS (ρ= -0.88, -0.89). LT was associated with increased IFD using GEE, WRS, and ZINB, but not competing risks model. (Table) LT was associated with increased VFD using GEE and WRS, but not ZINB or competing risks models. Conclusion: IFD and VFD differentiated OHCA interventions, suggesting their utility. IFD and VFD were highly correlated with MRS, suggesting validity. IFD and VFD have important features that may influence OHCA trial design.

Comparison of the efficacy of supraglottic airway devices in low-risk adult patients: a network meta-analysis and systematic review

Numerous supraglottic airway device (SADs) have been designed for adults; however, their relative efficacy, indicated by parameters such as adequacy of sealing, ease of application, and postinsertion complications, remains unclear. We conducted a systematic review and network meta-analysis to evaluate the efficacy of various SADs. We searched electronic databases for randomized controlled trials comparing at least two types of SADs published before December 2019. The primary outcomes were oropharyngeal leak pressure (OLP), risk of first-attempt insertion failure, and postoperative sore throat rate (POST). We included 108 studies (n = 10,645) comparing 17 types of SAD. The Proseal laryngeal mask airway (LMA), the I-gel supraglottic airway, the Supreme LMA, the Streamlined Liner of the Pharynx Airway, the SoftSeal, the Cobra Perilaryngeal Airway, the Air-Q, the Laryngeal Tube, the Laryngeal Tube Suction II, the Laryngeal Tube Suction Disposable, AuraGain, and Protector had significantly higher OLP (mean difference ranging from 3.98 to 9.18 cmH2O) compared with that of a classic LMA (C-LMA). The Protector exhibited the highest OLP and was ranked first. All SADs had a similar likelihood of first-attempt insertion failure and POST compared with the C-LMA. Our findings indicate that the Protector may be the best SAD because it has the highest OLP.Systematic review registration PROSPERO: CRD42017065273.

Effectiveness of selected alternative methods of airway management by the nursing staff

Aim. The aim of the study was to assess the effectiveness of selected methods of alternative airway management by nursing staff. Material and methods. A prospective, pilot observational study was conducted on a group of 51 nurses undergoing specialization training or with specialty. Each nurse managed the airway with a laryngeal mask (LMA-Laryngeal Mask) and a laryngeal tube (LT-D-Laryngeal Tube) on a BT-CSIE trainer, and then carried out one minute ventilation using a bag valve mask, according to possessed knowledge and skills. The obtained parameters (time, pressure on the incisors, head tilt, ventilation quality) were recorded using a dedicated tablet. Statistical analysis was performed using the IBMSPSS Statistics 20 package. Results. No statistically significant differences were observed between the trials to open the airway using LMA and LT-D. Higher efficiency of LMA airway opening was demonstrated in the first trial and the average tidal volume during ventilation in relation to LT-D (LMA 547.84ml vs. LT-D 522.63ml). In addition, there was a significant difference in pressure on the incisors (LMA 6.82N vs. LT-D 4.12N). Conclusions. The effectiveness of LMA and LT-D insertion was assessed at a high level, with no significant differences between them. Variables: age, seniority, education level and type of specialization did not significantly differentiate the results obtained.

Using supraglottic airways by paramedics for airway management in analogue microgravity increases speed and success of ventilation

In the next few years, the number of long-term space missions will significantly increase. Providing safe concepts for emergencies including airway management will be a highly challenging task. The aim of the present trial is to compare different airway management devices in simulated microgravity using a free-floating underwater scenario. Five different devices for airway management [laryngeal mask (LM), laryngeal tube (LT), I-GEL, direct laryngoscopy (DL), and video laryngoscopy (VL)] were compared by n = 20 paramedics holding a diving certificate in a randomized cross-over setting both under free-floating conditions in a submerged setting (pool, microgravity) and on ground (normogravity). The primary endpoint was the successful placement of the airway device. The secondary endpoints were the number of attempts and the time to ventilation. A total of 20 paramedics (3 female, 17 male) participated in this study. Success rate was highest for LM and LT and was 100% both during simulated microgravity and normogravity followed by the I-GEL (90% during microgravity and 95% during normogravity). However, the success rate was less for both DL (60% vs. 95%) and VL (20% vs. 60%). Fastest ventilation was performed with the LT both in normogravity (13.7 ± 5.3 s; n = 20) and microgravity (19.5 ± 6.1 s; n = 20). For the comparison of normogravity and microgravity, time to ventilation was shorter for all devices on the ground (normogravity) as compared underwater (microgravity). In the present study, airway management with supraglottic airways and laryngoscopy was shown to be feasible. Concerning the success rate and time to ventilation, the optimum were supraglottic airways (LT, LM, I-GEL) as their placement was faster and associated with a higher success rate. For future space missions, the use of supraglottic airways for airway management seems to be more promising as compared to tracheal intubation by DL or VL.

Evaluation of the Complications Effectiveness and Frequency When Using Second-Generation Supraglottic Airways in Laparoscopic Interventions in the Trendelenburg Position

Relevance. The supraglottic airways (SA) are now more and more often used as devices of the first choice for providing ventilation during surgical interventions of low trauma and duration, during laparoscopic operations as well. Nevertheless, some concerns remain about the possibility of using these devices in operations accompanied by a significant increase in intra-abdominal pressure, for example, when performing laparoscopy, especially in the Trendelenburg position.Aim of study. Comparison of the efficiency and safety of ventilation, the incidence of postoperative complications when using two different types of SA during laparoscopic surgical interventions performed in the Trendelenburg position.Material and methods. Eighty-three gynecological patients who were scheduled to undergo laparoscopic surgery in the Trendelenburg position were randomly assigned to two groups. In the 1st group, a laryngeal tube was installed for general anesthesia, in the 2nd group patients had a laryngeal mask. The adequacy of ventilation, gas exchange rates, oropharyngeal leakage pressure, rate of successful placement, mean and peak airway pressure at various stages of surgery, as well as the frequency of intra- and postoperative complications were assessed.Results. In all observations, there were normal indicators of gas exchange and capnography, no leakage of the breathing mixture from the circuit. The level of oropharyngeal leakage pressure was statistically different in the groups and was 32 (28; 35) in the 1st group and 28.5 (27; 31.8) cm of water column in the 2nd group. (p=0.007). The time to the onset of ventilation was 19s (18; 21) in the laryngeal tube group, 21s (19; 22.5) in the laryngeal mask group; statistically significant differences were not obtained by this criterion (p=0.059). The first installation attempt was successful in 40 cases (93%) in the 1st group and in 38 cases (95%) in the 2nd group; there was no significant difference in this indicator (p=0.94). The peak and mean airway pressure at the stages of surgery also did not differ. The study did not reveal such intraoperative complications as dislocation of the airway and aspiration of gastric contents. When analyzing postoperative complications, statistical differences were obtained in terms of the level of sore throat 3 hours after removal of SA. In terms of sore throat after 5 minutes, 6, 12, 24 hours, the frequency of hoarseness, no differences were found.Conclusion. 1. The use of different types of 2nd generation supraglottic airways with inflatable cuff (s) provides reliable protection of the upper airway during anesthesia and effective ventilation during laparoscopic surgery in the Trendelenburg position. 2. The laryngeal mask and laryngeal tube did not differ significantly in the frequency of successful insertion, ventilation efficiency, airway pressure levels at various stages of surgery, and the incidence of intra- and postoperative complications. 3. The use of a laryngeal tube provided a higher level of oropharyngeal leakage pressure, while the differences with the laryngeal mask for this indicator were statistically significant.

Effectiveness of Supraglottic Airways Management Among Paramedics

Aim: The aim of the study was to evaluate the effectiveness of supraglottic airways management by paramedics using selected methods in simulated conditions. Material and methods: The study included a group of 115 professionally active paramedics working in various health care facilities in the Podkarpackie Province. Each subject was asked to open the airways using a laryngeal mask airway (LMA) and a disposable laryngeal tube (LT-D) in simulated conditions. The study assessed the effectiveness of the airway opening taking into account: average tidal volume of a single breath in ml, average minute tidal volume in ml, time of insertion in seconds, the need for a second attempt, pressure on incisors in N. The obtained results were statistically analysed, p<0.05 was considered statistically significant. The calculations were performed with the SPSS 20 software. results: The study showed that the time of inserting of LT-D is the same as the time of LMA (LT-D: 25.95s ± 7.89s vs. LMA: 24.78s ± 8.32s; p>0.05). The mean tidal volume of a single breath was significantly higher with the LMA com-pared to LT-D (LMA 633.24 ml vs. LT-D 579.68 ml, p<0.05). During LMA insertion, the pressure on incisors of 11.41N ± 6.22N was used, while in case of LT-D this pressure amounted to 13.15N ± 3.68N. Every fourth examined paramedic had problems with correct insertion of LT-D tube in accordance with the adopted algorithm. Conclusions: The supralottic LMA and LT-D tools seem to be an effective and safe alternative of the airway management in case of life emergency