***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: AIM Outcomes from out-of-hospital cardiac arrest ( OHCA ) may improve if rescuers perform chest compressions ( CCs ) deeper than the previous recommendation of 38 - 51 mm and consistent with the 2010 AHA Guideline recommendation of at least 51 mm . The aim of this study was to assess the relationship between CC depth and OHCA survival . METHODS Prospect i ve analysis of CC depth and outcomes in consecutive adult OHCA of presumed cardiac etiology from two EMS agencies participating in comprehensive CPR quality improvement initiatives . ANALYSIS Multivariable logistic regression to calculate adjusted odds ratios ( aORs ) for survival to hospital discharge and favorable functional outcome . RESULTS Among 593 OHCAs , 136 patients ( 22.9 % ) achieved return of spontaneous circulation , 63 patients ( 10.6 % ) survived and 50 had favorable functional outcome ( 8.4 % ) . Mean CC depth was 49.8±11.0 mm and mean CC rate was 113.9±18.1CCmin(-1 ) . Mean depth was significantly deeper in survivors ( 53.6 mm , 95 % CI : 50.5 - 56.7 ) than non-survivors ( 48.8 mm , 95 % CI : 47.6 - 50.0 ) . Each 5 mm increase in mean CC depth significantly increased the odds of survival and survival with favorable functional outcome : aORs were 1.29 ( 95 % CI 1.00 - 1.65 ) and 1.30 ( 95 % CI 1.00 - 1.70 ) respectively . CONCLUSION Deeper chest compressions were associated with improved survival and functional outcome following OHCA . Our results suggest that adhering to the 2010 AHA Guideline -recommended depth of at least 51 mm could improve outcomes for victims of OHCA Objective To investigate whether real-time audio and visual feedback during cardiopulmonary resuscitation outside hospital increases the proportion of subjects who achieved prehospital return of spontaneous circulation .  Design A cluster-r and omised trial . Subjects 1586 people having cardiac arrest outside hospital in whom resuscitation was attempted by emergency medical services ( 771 procedures without feedback , 815 with feedback ) . Setting Emergency medical services from three sites within the Resuscitation Outcomes Consortium in the United States and Canada . Intervention Real-time audio and visual feedback on cardiopulmonary resuscitation ( CPR ) provided by the monitor-defibrillator . Main outcome measure Prehospital return of spontaneous circulation after CPR . Results Baseline patient and emergency medical service characteristics did not differ between groups . Emergency medical services muted the audible feedback in 14 % of cases during the period with feedback . Compared with CPR clusters lacking feedback , clusters assigned to feedback were associated with increased proportion of time in which chest compressions were provided ( 64 % v 66 % , cluster-adjusted difference 1.9 ( 95 % CI 0.4 to 3.4 ) ) , increased compression depth ( 38 v 40 mm , adjusted difference 1.6 ( 0.5 to 2.7 ) ) , and decreased proportion of compressions with incomplete release ( 15 % v 10 % , adjusted difference −3.4 ( −5.2 to −1.5 ) ) . However , frequency of prehospital return of spontaneous circulation did not differ according to feedback status ( 45 % v 44 % , adjusted difference 0.1 % ( −4.4 % to 4.6 % ) ) , nor did the presence of a pulse at hospital arrival ( 32 % v 32 % , adjusted difference −0.8 ( −4.9 to 3.4 ) ) , survival to discharge ( 12 % v 11 % , adjusted difference −1.5 ( −3.9 to 0.9 ) ) , or awake at hospital discharge ( 10 % v 10 % , adjusted difference −0.2 ( −2.5 to 2.1 ) ) . Conclusions Real-time visual and audible feedback during CPR altered performance to more closely conform with guidelines . However , these changes in CPR performance were not associated with improvements in return of spontaneous circulation or other clinical outcomes . Trial Registration Clinical Trials Objective : Guidelines for cardiopulmonary resuscitation recommend a chest compression rate of at least 100 compressions/min . A recent clinical study reported optimal return of spontaneous circulation with rates between 100 and 120/min during cardiopulmonary resuscitation for out-of-hospital cardiac arrest . However , the relationship between compression rate and survival is still undetermined . Design : Prospect i ve , observational study . Setting : Data is from the Resuscitation Outcomes Consortium Prehospital Resuscitation IMpedance threshold device and Early versus Delayed analysis clinical trial . Participants : Adults with out-of-hospital cardiac arrest treated by emergency medical service providers . Interventions : None . Measurements Main Results : Data were abstract ed from monitor-defibrillator recordings for the first five minutes of emergency medical service cardiopulmonary resuscitation . Multiple logistic regression assessed odds ratio for survival by compression rate categories ( < 80 , 80–99 , 100–119 , 120–139 , ≥140 ) , both unadjusted and adjusted for sex , age , witnessed status , attempted byst and er cardiopulmonary resuscitation , location of arrest , chest compression fraction and depth , first rhythm , and study site . Compression rate data were available for 10,371 patients ; 6,399 also had chest compression fraction and depth data . Age ( mean ± SD ) was 67 ± 16 years . Chest compression rate was 111 ± 19 per minute , compression fraction was 0.70 ± 0.17 , and compression depth was 42 ± 12 mm . Circulation was restored in 34 % ; 9 % survived to hospital discharge . After adjustment for covariates without chest compression depth and fraction ( n = 10,371 ) , a global test found no significant relationship between compression rate and survival ( p = 0.19 ) . However , after adjustment for covariates including chest compression depth and fraction ( n = 6,399 ) , the global test found a significant relationship between compression rate and survival ( p = 0.02 ) , with the reference group ( 100–119 compressions/min ) having the greatest likelihood for survival . Conclusions : After adjustment for chest compression fraction and depth , compression rates between 100 and 120 per minute were associated with greatest survival to hospital discharge OBJECTIVE Agonal breathing is present in up to 40 % of pre-hospital cardiac arrests and is commonly mistaken as a sign of circulation leading to omission of byst and er resuscitation . The aim of this study was to test the hypothesis that specific tuition on agonal breathing improves the accuracy of checking for signs of circulation as a diagnostic test for cardiac arrest . METHODS First year medical students were r and omised to control or intervention groups . The control group were taught st and ard CPR according to current guidelines . The intervention group received st and ard CPR training plus specific tuition on the characteristics of agonal breathing . Two weeks after initial training , the students ' ability to recognise cardiac arrest was tested using a simulated cardiac arrest victim demonstrating normal , absent or agonal breathing . Diagnostic accuracy , sensitivity and specificity for the decision to start CPR was calculated . RESULTS Sixty-four students were equally r and omised to intervention and control groups . The intervention group had greater diagnostic accuracy for cardiac arrest compared to the control group ( 90 % versus 78 % , P=0.03 ) . The intervention group were more likely to recognise cardiac arrest correctly and initiate CPR than the control group ( sensitivity 90 % versus 78 % , P=0.02 ) . The improved results were predominantly due to recognition that agonal breathing is a sign of cardiac arrest ( 75 % intervention group versus 43 % control group , P=0.01 ) . CONCLUSION This study demonstrates improved diagnostic accuracy and sensitivity of " checking for signs of circulation " by teaching CPR providers to recognise agonal breathing as a sign of cardiac arrest BACKGROUND Current international resuscitation guidelines for lay people rely on the assessment of " normal breathing " as a key sign of breathing and circulation . However , it is not known how accurately laypersons can discriminate between " normal " and " abnormal " breathing . The aim of this study was to test the ability of medical students to discriminate between simulated normal and abnormal breathing patterns and select the correct treatment . METHODS Six video clips of simulated breathing were recorded showing : normal ; abnormal -shallow , rapid , agonal ( obstructed and unobstructed airways ) ; or absent breathing . The clips were vali date d by three experienced emergency practitioners and then shown in a r and om order to 48 second-year medical students . For each clip observers were asked to indicate : " Is this patient breathing ? " ( yes-normal , yes-abnormal , no ) and " What action would you take ? " ( rescue breathing or recovery position ) . RESULTS All experts correctly identified the breathing type and agreed on an appropriate emergency action . Students identified normal breathing as : normal 61 % , abnormal 33 % and absent 6 % ; abnormal breathing as : normal 29 % , abnormal 61 % , absent 10 % ; and absent breathing as : normal 8 % , abnormal 6 % , absent 85 % . Correct actions were selected in 86 % during normal breathing , 51 % during abnormal breathing and 86 % during absent breathing . The sensitivity for observers correctly identifying normal from abnormal breathing was 60 % and specificity 75 % and for selecting the correct action was 42 % and 80 % , respectively . CONCLUSIONS Medical students were unable to identify normal breathing from abnormal breathing reliably result ing in a high number of inappropriate , potentially harmful actions . Further evaluation of the optimal method for assessing for signs of breathing and circulation is required Background : The 2010 international guidelines for cardiopulmonary resuscitation recently recommended an increase in the minimum compression depth from 38 to 50 mm , although there are limited human data to support this . We sought to study patterns of cardiopulmonary resuscitation compression depth and their associations with patient outcomes in out-of-hospital cardiac arrest cases treated by the 2005 guideline st and ards . Design : Prospect i ve cohort . Setting : Seven U.S. and Canadian urban regions . Patients : We studied emergency medical services treated out-of-hospital cardiac arrest patients from the Resuscitation Outcomes Consortium Epistry – Cardiac Arrest for whom electronic cardiopulmonary resuscitation compression depth data were available , from May 2006 to June 2009 . Measurements : We calculated anterior chest wall depression in millimeters and the period of active cardiopulmonary resuscitation  ( chest compression fraction ) for each minute of cardiopulmonary resuscitation . We controlled for covariates including compression rate and calculated adjusted odds ratios for any return of spontaneous circulation , 1-day survival , and hospital discharge . Main Results : We included 1029 adult patients from seven U.S. and Canadian cities with the following characteristics : Mean age 68 yrs ; male 62 % ; byst and er witnessed 40 % ; byst and er cardiopulmonary resuscitation 37 % ; initial rhythms : Ventricular fibrillation/ventricular tachycardia 24 % , pulseless electrical activity 16 % , asystole 48 % , other nonshockable 12 % ; outcomes : Return of spontaneous circulation 26 % , 1-day survival 18 % , discharge 5 % . For all patients , median compression rate was 106 per minute , median compression fraction 0.65 , and median compression depth 37.3 mm with 52.8 % of cases having depth < 38 mm and 91.6 % having depth < 50 mm . We found an inverse association between depth and compression rate ( p < .001 ) . Adjusted odds ratios for all depth measures ( mean values , categories , and range ) showed strong trends toward better outcomes with increased depth for all three survival measures . Conclusions : We found suboptimal compression depth in half of patients by 2005 guideline st and ards and almost all by 2010 st and ards as well as an inverse association between compression depth and rate . We found a strong association between survival outcomes and increased compression depth but no clear evidence to support or refute the 2010 recommendations of > 50 mm . Although compression depth is an important component of cardiopulmonary resuscitation and should be measured routinely , the most effective depth is currently unknown . ( Crit Care Med 2012 ; 40:–1198 OBJECTIVE To evaluate smartphone apps intended for self-management of pain using quality assessment criteria and usability testing with prospect i ve users . DESIGN 1 ) Survey and content analysis of available apps ; and 2 ) individual usability study of two apps . SETTING University of Leeds , United Kingdom . PARTICIPANTS Forty-one participants ( aged 19 - 59 years ) with experience of chronic or recurrent pain episodes . METHODS We undertook a survey , content analysis , and quality appraisal of all currently available mobile phone apps for self-management of pain . Two apps were then selected and assessed with usability testing . RESULTS Twelve apps met the inclusion criteria . The quality assessment revealed wide variation in their clinical content , interface design , and usability to support self-management of pain . Very little user or clinician involvement was identified in the development of the apps . From the usability testing , participants stated a preference for an interface design employing a lighter color scheme and particular text font . Although very few participants were aware of pain-reporting apps prior to participation , many would consider use in the future . CONCLUSIONS Variation in app quality and 
    Output:
    
This is of exceptional importance for apps dealing with the treatment of life-threatening events such as cardiac arrest