Benefit of the SALAD Technique on CPR Quality During Intubation in Contaminated Airway

Overview

Management of airways in contaminated environments can compromise the quality of cardiopulmonary resuscitation (CPR). This study examined the effectiveness of SALAD (Suction Assisted Laryngoscopy Airway Decontamination) compared to intermittent suction in maintaining CPR quality during intubation in a simulated scenario of regurgitation. Following 2.5 hours of training in the SALAD technique, 36 emergency medicaltechnician-paramedics (EMT-Ps) were randomly assigned in equal numbers to two groups: one utilizing the SALAD technique and the other employing intermittent suction during intubation on a manikin. The manikin simulates regurgitation of gastric contents into the oropharynx during CPR. Primary outcomes assessed were CPR quality metrics, such as chest compression rate, depth, and interruption. Secondary outcomes included the success rate and time of intubation.

The study was conducted in March 2024. Participants were emergency medical technician-paramedics (EMT-Ps) employed by fire departments across Taiwan, recruited on a nationwide basis. All participants provided signed informed consent forms. 36 EMT-Ps are involved in this study. Simulation setup : The CPR-induced regurgitation model was adapted from an Airway Larry Airway Management Trainer Torso (Nasco, Fort Atkinson, WI, USA) to simulate oropharyngeal regurgitation during CPR. To emulate the stomach, a manual pump was attached at the base of the manikin's torso. A transparent vinyl tube connected the manikin's esophagus to the pump's outlet port. A HQCPR device was used for CPR quality record. Training program The 36 participants received 2.5 hours of SALAD training. The training included 5 rounds of intubation teaching and practice. The first two rounds of training involve using the SALAD technique with the video laryngoscope, while the third round used the C-MAC S video laryngoscope as a direct laryngoscope for practice. Technique adjustments can be made during the initial three rounds through monitoring with the video system. The fourth round will involve intubation using a direct laryngoscope with a size 3 Macintosh blade on the SALAD Simulator. The final round involved intubation on the CPR-induced regurgitation model, using a direct laryngoscope and employing the SALAD technique for intubation during chest compressions. Simulation protocol After completing 2.5 hours of training, participants were randomly assigned to one of two groups for suction techniques: SALAD or intermittent suction. Randomization was conducted using the simple randomization method with a random number table. Participants assigned to the same suction technique group formed a resuscitation team, taking on roles as the airway manager, first chest compressor, or second chest compressor. Each participant rotated through these three roles during three simulation sessions.In each simulation, the airway manager was responsible for BVM ventilation and intubation. The first and second chest compressors performed chest compressions alternately, once every five CPR cycles, adhering to a 30:2 compression-to- ventilation ratio. The initial 30 chest compressions were followed by two ventilations, and suction was not performed during this phase, even if regurgitation was present. This was intended to simulate a scenario where the oral cavity was filled with regurgitant material during intubation, maintaining consistency across participants. After the first two ventilations, intubation could proceed while the team continued chest compressions. The airway manager could request a temporary reduction, lightening, or even cessation of chest compressions to facilitate intubation, or to continue up to 60 compressions without interruption if necessary. If the intubation attempt was unsuccessful, the airway manager had to administer two BVM ventilations before attempting intubation again. Depending on the group assignment, either SALAD or intermittent suction techniques were employed to assist in airway decontamination. After intubation, the airway manager assessed lung expansion using the BVM to verify successful intubation. A failed intubation was defined as any esophageal intubation or three unsuccessful intubation attempts. Each simulation concluded following either a successful or failed intubation. Measurement The primary outcomes were CPR quality metrics, including chest compression rate, chest compression depth, and time of interruption. The secondary outcomes were the intubation success rate and intubation time. The rate and depth of the first 30 chest compressions (pre-intubation period) were measured. After the initial 30 compressions, interruptions for ventilation or airway management, as well as the quality of chest compressions during intubation, were also measured (intubation period). An intubation attempt was defined as the insertion of the laryngoscope blade into the mouth and its subsequent withdrawal during an unsuccessful attempt, or as the insertion of the laryngoscope blade followed by confirmation from the airway manager that the tube was inserted. Intubation time was defined as the period between the start and the end of an intubation attempt. Two video cameras were set up to record the entire simulation process. Two observers reviewed the video records independently to identify any intubation attempts. Disagreements were resolved by reaching a mutual consensus. The HQCPR application on an Android device recorded chest compression depth, rate, and interruptions (defined as no chest compression for more than 1 second). The data from both the video recordings and the HQCPR application were used in subsequent analyses. Statistical analysis The characteristics of EMT-Ps were described using frequency and percentage for categorical variables, while mean values with standard deviation (SD) were used for continuous variables. Continuous data were compared using the independent t-test between the SALAD and intermittent suction groups, while categorical data were compared using the Fisher's exact test or the Chi-Squared test between these two groups. CPR quality metrics and intubation time were summarized using mean values with 95% confidence intervals (CI). Compression depth greater than or equal to 5 cm, first-pass intubation success, and esophageal intubation were presented as frequency and percentage. Continuous data were compared using the independent t test between the SALAD and intermittent suction groups, while categorical data were compared using Fisher's exact test between these two groups. CPR quality metrics between the pre-intubation period and the intubation period were analyzed using the paired t test in both the SALAD and intermittent suction groups. A two- tailed p-value of less than 0.05 indicated statistical significance. All data analyses and sample size determination were performed using MedCalc Statistical Software version 22.023 (MedCalc Software, Ostend, Belgium).