Chest Compression Fraction in Simulated Cardiac Arrest Management by Primary Care Paramedics: King Laryngeal Tube Airway versus Basic Airway Management
Prehospital Emergency Care: Posted online on January 10, 2013.
The objective of this randomised simulation study was to determine whether use of the King laryngeal tube (KLT) airway resulted in differences in chest compression fraction (CCF) during simulated cardiac arrest managed by primary care paramedics (PCPs), as compared with basic airway management (bag–mask ventilation [BMV]).
The KLT was introduced to all providers in the EMS system at the time of study initiation. All participants received the same training, and were not aware that the primary outcome of the study was CCF. Standard airway management by PCPs prior to this was BMV. Pairs of PCPs were randomized to use KLT or BMV during a scripted 6-minute cardiac arrest scenario. The scenarios were videotaped, and data were abstracted by a single investigator. The CCF was calculated (fraction of time chest compressions were done/total scenario time). The CCF, number of seconds to first ventilation, and number of seconds to first compression were compared using the Mann-Whitney U test.
Sixty-seven pairs of PCPs participated: 30 in the KLT arm and 37 in the BMV arm. Demographics were similar in each group: KLT 68.3% males, BMV 55.4% males; KLT mean age 33.52 years), BMV mean age 32.07 years; and KLT mean years of experience 9.03, BMV mean years of experience 6.59. The CCF was higher in the KLT group: median 0.82 compared with the BMV group: median 0.70. Time to first ventilation was longer in the KLT group: median 83.00 sec than in the BMV group: median 48.00 sec. Times to first compression were similar: KLT median 13.00 sec, BMV median 14.00 sec .
It was found in this randomised simulation study, KLT use by PCPs during simulated standard cardiac arrest scenarios was found to significantly increase CCF compared with basic airway management with BMV. These results are likely to be seen with majority of types of supraglottic airways when compared with basic airway management methods as once the device is correctly located, the requirement to maintain an effective seal, one of the interruptions to effective CPR, is eliminated and continuous compressions can be performed. Considering the results state it took 35 seconds longer to achieve the first ventilation with the KLT, it should be noted that about a third of KLT pairs placed the device before providing the first ventilation while others placed the KLT at just over two minutes into the scenario. The amount of time without CPR per minute of the scenario was the same in both groups in the first 3 minutes, but significantly less in minutes 3 to 6 when the KLT was used.
The authors also note that while the study provides some evidence that the use of KLT may improve CCF, it is unknown how this would translate into the real-world setting, or whether this intervention would improve survival.