Coparative Study Of Mechanical And Manual Chest Compression In Hospital After Cardiac Arrest

Background:CPR is the key technology to rescue patients after cardiac arrest.Traditional way of manual CPR has lots of disadvantages as unstable compression speed、insufficient compression depth、easy to be tired and low efficiency of ventilation.As to make up for such disadvantages,mechanical CPR technology has come up and developed.Although there are no enough evidence to prove that mechanical CPR can replace manual CPR,current studies have already proved that mechanical chest compression has the equal quality as manual ways.In 2015,the AHA CPR guidelines define high-quality CPR as:compress chest with adequate rate（100-120/min）and depth（at least 2 inches/5 cm and no more than 2.4inches/6 cm）,allow full recoil of chest after each compression;do not lean on the chest after each compression and limit interruptions in chest compressions to less than 10 seconds^[1].The new guidelines have emphasized the importance of high-quality chest compressions and set more specific range of compression rate and depth.Therefore,we suppose that mechanical chest compression can provide better CPR quality than manual chest compression based on the new guidelines.Objective:To compare the differences of mechanical CPR qualities and manual CPR qualities via different observational data according to the 2015 AHA CPR guidelines and analyze the possible reasons of the differences.Methods:Our study has two parts.Part I aims to compare the quality of mechanical and manual chest compression by new types of CPR manikins and CPR quality feedback devices.Part II aims to analyze and compare the differences of mechanical and manual CPR quality by real-time video recording system of cardiac arrest patients treated in our emergency department.Results:Part I:there are statistical differences between mechanical CPR（LUCAS/SCC）andmanualCPRinaveragecompression depth（53.56/52.06 VS 48.86,P=0.021/0.008）、rate of accurate compression recoil（98.64%/96.92%VS 91.28%,P<0.001）、average activation time（24.17/22.67 VS 9.86,P<0.001）and average interruption times（15.78/17.61 VS 16.81,P=0.007/0.03）but no difference in percentage of effective compression time（P=0.438/0.684）or average compression rate（P=0.910/0.860）or average interruption time（P=0.332/0.092）.Part II:131cases have been finally enrolled in our clinical study from December 2015to February 2017.75 patients were rescued by mechanical CPR devices（40 with LUCAS and 35 with SCC）and 56 by manual CPR.There are no difference between mechanical CPR group（LUCAS/SCC）and manual CPR group in 24-hour survival rate（P=0.311/0.767）or ROSC rate（P=0.269/0.315）and no difference in average activation time or average interruption times or average interruption time.Conclusion:Mechanical chest compressions has better compression depth and compression recoil than manual chest compression in hospital after cardiac arrest but doesn’t improve 24-hour survival rate or rate of spontaneous circulation.