Sheffield Hospitals and Trust Brings Translational Research to Clinical Practice

Sheffield Hospitals and Trust are bringing translational research to clinical practice and using new technology to help staff deliver high quality care, no matter who responds to a patient in cardiac arrest. This article will discuss key research articles and how they have been brought to clinical practice in the Sheffield system. This article will also discuss the choice of a new defibrillator throughout the trust and how its adoption was guided by recent research in resuscitation. Sheffield Teaching Hospitals and Trust manages five adult hospitals in Sheffield, England with a combined total of 1,964 beds and a staff of 12,200. Royal Hallamshire and Northern General are two of the United Kingdom’s largest acute hospitals, and this trust has been named two years running as the top performing trust in the UK Good Hospital Guide. There are over 600 cardiac arrests annually, so the focus of the resuscitation officers in the trust is on improving outcomes in every possible way. The Sheffield Teaching Hospitals Trust works closely with Sheffield Children’s Hospital and the University of Sheffield to ensure they are on the cutting edge of research and development. For many years the focus on improving outcomes from cardiac arrest has centered around early defibrillation, with clinicians knowing that the ability to convert a patient in ventricular fibrillation (VF) or ventricular tachycardia (VT) is very much related to time to first shock. A recent study by Chan et al published in the New England Journal of Medicine in 2008 reviewed data from the National Registry of Cardiopulmonary Resuscitation (NRCPR).1 The authors demonstrated that in general the window for effective termination of VF/VT was in actuality closer to two minutes rather than the three minutes previously thought. More importantly, the study showed that the overall shock success was directly correlated with time, with the likelihood of a successful conversion decreasing from 100% at two minutes to 38% at seven minutes. This study illustrated that institutions that relied on the arrival of a code team for delivery of a timely shock were most likely reducing the chance for a good outcome. The reasons for this time to first shock relationship are readily understood. Research by Eftestøl et al showed that after three to five minutes of VF, the ATP in the myocardial cells was depleted and the rhythm changed from a coarse VF to a fine VF that is resistance to conversion.² Peberdy et al further demonstrated that outcomes from cardiac arrest decline significantly during nights and weekends, when lighter staffing may lead to delays in delivery of therapy.³ This research led Sheffield to look for a solution for delivery of early defibrillation that would be readily adopted by the basic life support (BLS) trained responders, yet ensured a smooth transition to advanced cardiac life support (ACLS) without needing to stop to change cables or pads. While we considered using a layperson AED on our wards, this then necessitated changing out the cables and defibrillator pads to be compatible with the manual defibrillator when it arrived. Conversely, experience showed that BLS-trained providers were not comfortable using a manual defibrillator, even one that had a clearly marked AED button. Therefore, the R Series® Plus defibrillator (ZOLL Medical Corporation, Chelmsford, MA) seemed to fit the bill. When it is turned on, only a single AED button is displayed, and the unit can be configured to either immediately begin analysis or prompt the rescuer to start cardiopulmonary resuscitation (CPR). When the ACLS team arrives, the press of a key illuminates the entire manual defibrillator face, allowing the team to take over without pause. However, that didn’t provide a whole solution. The International Liaison Committee on Resuscitation (ILCOR) guidelines published in 2005 clearly demonstrated that the quality of CPR was critical to improving outcomes from sudden cardiac arrest (SCA). However, research carried out in the early years of the current decade clearly showed that CPR quality was poor, both in out-of-hospital arrests as well as in-hospital. Wik et al measured the CPR performance of professional rescuers treating patients who arrested out of hospital. He showed that not only were the rate and depth of compressions far from the guidelines, but that pauses were frequent,4 so frequent in fact that CPR was on average being performed during only 38% of the time available — after adjusting for pulse checks and shocks. Similar data was reported in hospitals when Abella et al measured the performance of clinical staff at the University of Chicago Hospitals.5 Overall compressions measured were too shallow and too slow, and while the average rates and depth approached guidelines, the amount of time that both rate and depth were correct in a single compression was very small. Furthermore, when Abella correlated quality of CPR with the likelihood of shock success, he was able to demonstrate that both rate and depth are correlated to the likelihood of shock success. Pauses were also long and frequent. Further work by Edelson et al showed that the length of pre-shock pauses was inversely correlated with achievement of return of spontaneous circulation (ROSC), meaning that the longer the pause before shock delivery, the less likely the shock would be successful.⁶ A poster presented by Peberdy et al at the 2008 Resuscitation Science Symposium held in conjunction with the American Heart Association tested the impact of audible and visual feedback on the quality of CPR performed.⁷ A series of 125 health professionals were asked to perform two minutes of uninterrupted CPR on a manikin using an AED that had been modified to offer no guidance with regard to CPR quality. The rate and depth of each compression was recorded, and the performance was scored as “% Compressions in Target.” The measure indicates the percent of the time each compression was delivered at the correct rate and depth — in the same compression. After a brief rest, the participants were then given a brief in-service on an AED with CPR feedback. This unit provided a metronome that sounded at the correct rate throughout the period. In addition, audio prompts directed rescuers to press harder when the compressions were not in target. A depth indicator also provided visual guidance to the depth of each compression. Participants then performed two more minutes of CPR following the guidance of the AED. A total of 105 data sets were collected. When using the silent AED, the health professionals averaged only 18% compressions in target. Using the feedback, the percentage in target rose to an impressive 80%. Sheffield Teaching Hospitals also participated in a CPR challenge at the hospital, and our results echoed those of the researchers. The data was clear: whatever device we chose for Sheffield, it had to offer CPR feedback if the first responders were to deliver optimal CPR. We chose the R Series Plus, since it offers audible feedback for rate and depth and a CPR index that offers visual indication of good perfusion. The final issue was pauses. One major source of pauses was immediately after delivery of a shock; time ticked away as staff performed a pulse check and evaluated the post-shock rhythm. We found that the See-Thru CPR feature of ZOLL’s ALS defibrillator was specifically designed to address this problem as it filtered the CPR artifact from the ECG, allowing rescuers to determine if there was an organized rhythm developing without the need to pause compressions as frequently.8 The See-Thru CPR feature is automatically activated when the R Series Plus is placed in manual mode. As Sheffield begins to deploy our newest acquisition, we will be tracking outcomes to see how well this new technology improves such key measures as time to first shock, quality of CPR, and most importantly, patients who achieve ROSC and ultimately survive to leave the hospital.