Wrist band photoplethysmography in detection of individual pulses in atrial fibrillation and algorithm-based detection of atrial fibrillation.

AIMS: Atrial fibrillation (AF) is the most common tachyarrhythmia and a significant cause of cardioembolic strokes. Atrial fibrillation is often intermittent and asymptomatic making detection a major clinical challenge. We evaluated a photoplethysmography (PPG) wrist band in individual pulse detection in patients with AF and tested the reliability of two commonly used algorithms for AF detection. METHODS AND RESULTS: A 5-min PPG was recorded from patients with AF or sinus rhythm (SR) with a wrist band and analysed with two AF detection algorithms; AFEvidence and COSEn. Simultaneously registered electrocardiogram served as the golden standard for rhythm analysis and was interpreted by two cardiologists. The study population consisted of 213 (106 AF, 107 SR) patients. The wrist band PPG achieved individual pulse detection with a sensitivity of 91.7 ± 11.2% and a positive predictive value (PPV) of 97.5 ± 4.6% for AF, with a sensitivity of 99.4 ± 1.5% [7.7% (95% confidence interval, 95% CI 5.5% to 9.9%); P < 0.001] and PPV of 98.1 ± 4.1% [0.6% (95% CI -0.6% to 1.7%); P = 0.350] for SR. The pulse detection sensitivity was lower 86.7 ± 13.9% with recent-onset AF (AF duration <48 h, n = 43, 40.6%) as compared to late AF (≥48 h, n = 63, 59.4%) with 95.1 ± 7.2% [-8.3% (95% CI -12.9% to -3.7%); P = 0.001]. For the detection of AF from the wrist band PPG, the sensitivities were 96.2%/95.3% and specificity 98.1% with two algorithms. CONCLUSION: The wrist band PPG enabled accurate algorithm-based detection of AF with two AF detection algorithms and high individual pulse detection. Algorithms allowed accurate detection of AF from the PPG. A PPG wrist band provides an easy solution for AF screening.

Witnessed out-of-hospital cardiac arrest- effects of emergency dispatch recognition.

BACKGROUND: Survival from an out-of-hospital cardiac arrest (OHCA) depends on the sequence of interventions in "the chain of survival". If OHCA is recognized in the emergency medical communication centre (EMCC), the proper emergency medical service (EMS) should be dispatched and cardiopulmonary resuscitation (CPR) instructions should be given to a bystander. The study aimed to examine the impact of OHCA recognition in the EMCC on survival rates and the main elements of the chain of survival. METHODS: Data from the Helsinki University Hospital's registry of OHCA patients between 1997 and 2013 were studied. Altogether, 2054 EMCC-handled and bystander-witnessed OHCA proven events of cardiac origin were analysed. RESULTS: In 80.5% of the victims, two EMS units were correctly dispatched and the OHCA was classified as recognized. Achieved return of spontaneous circulation (ROSC) and survival to hospital discharge were 49% and 23%, respectively, if cardiac arrest was recognized by the EMCC and 40% and 16% when it was not (P = 0.003 and 0.002). Dispatchers gave CPR instructions in 60% of the recognized OHCA cases. Bystander-performed CPR increased over time and was given in 58% of the recognized OHCAs and also in 17% of the unrecognized events. EMS delays were shorter if OHCA was recognized as opposed to unrecognized (8 min with an IQR 6.5-10 min vs. 9 min with an IQR 6.5-11 min; P = 0.001). CONCLUSIONS: Recognition of OHCA by the EMCC was significantly associated with an increased rate of bystander-performed CPR, reduced EMS response time, and increased OHCA patient ROSC and survival rates.

Nationwide survey of resuscitation education in Finland.

AIMS: Good-quality cardiopulmonary resuscitation (CPR) is highlighted in the International Resuscitation Guidelines, but clinically the quality of CPR is often poor. Education of CPR has a major role in the primary skills imparted to students. Different methods can be used to teach CPR quality. We evaluated the current status of their usage in Finland institutes teaching students of emergency medicine at different levels. METHODS: The following institutes were included in an anonymous survey: medical schools (teaching future physicians), universities of applied sciences (paramedics), colleges (emergency medical technicians) and emergency services college (fire-fighters). Hours of teaching theory lessons of CPR and hours of small group training were evaluated. In particular, we focussed on the teaching methods for adequate chest compression rate and depth. RESULTS: Twenty-one of 30 institutes responded to the questionnaire. The median for hours of theory lessons of CPR was 8h (range: 2-28 h). The median for hours of small group training was 10 (range: 3-40 h). The methods of teaching adequate chest compression rate were instructors' visual estimation in 28.5% of the institutions, watch in 33.3%, metronome in 9.5% and manikins' graphic in 28.5% of institutions. The methods of teaching adequate chest compression depth were instructors' visual estimation in 33.3%, in manikins light indicators in 23.8% and manikins' graphics in 52.3% of institutions. CONCLUSION: The hours of theoretic lessons and small group training vary widely among different institutes. In one-third of institutions, the instructor's visual estimation was a sole method used to teach adequate chest compression rate and depth. Different technical methods were surprisingly seldom used.

Quality of cardiopulmonary resuscitation on manikins: on the floor and in the bed.

BACKGROUND: In general, in-hospital resuscitation is performed in a bed and out-of-hospital resuscitation on the floor. The surface under the patient may affect the cardiopulmonary resuscitation (CPR) quality; therefore, we evaluated CPR quality (the percentage of chest compressions of correct depth) and rescuer's fatigue (the mean compression depth minute by minute) when CPR is performed on a manikin on the floor or in the bed. METHODS: Forty-four simulated cardiac arrest scenarios of 10 min were treated by intensive care unit (ICU) nurses in pairs using a 30 : 2 chest compression-to-ventilation ratio. The rescuer who performed the compressions was changed every 2 min. CPR was randomly performed either on the floor or in the bed without a backboard; in both settings, participants kneeled beside the manikin. RESULTS: A total number of 1060 chest compressions, 44% with correct depth, were performed on the floor; 1068 chest compressions were performed in the bed, and 58% of these were the correct depth. These differences were not significant between groups. The mean compression depth during the scenario was 44.9+/-6.2 mm (mean+/-SD) on the floor and 43.0+/-5.9 mm in the bed (P=0.3). The mean chest compression depth decreased over time on both surfaces (P<0.001), indicating rescuer fatigue, but this change was not different between the groups (P=0.305). CONCLUSIONS: ICU nurses perform chest compression as effectively on the floor as in the bed. The mean chest compression depth decreases over time, but the surface had no significant effect.

Influence of chest compression rate guidance on the quality of cardiopulmonary resuscitation performed on manikins.

AIMS: The adequate chest compression rate during CPR is associated with improved haemodynamics and primary survival. To explore whether the use of a metronome would affect also chest compression depth beside the rate, we evaluated CPR quality using a metronome in a simulated CPR scenario. METHODS: Forty-four experienced intensive care unit nurses participated in two-rescuer basic life support given to manikins in 10min scenarios. The target chest compression to ventilation ratio was 30:2 performed with bag and mask ventilation. The rescuer performing the compressions was changed every 2min. CPR was performed first without and then with a metronome that beeped 100 times per minute. The quality of CPR was analysed with manikin software. The effect of rescuer fatigue on CPR quality was analysed separately. RESULTS: The mean compression rate between ventilation pauses was 137+/-18compressions per minute (cpm) without and 98+/-2cpm with metronome guidance (p<0.001). The mean number of chest compressions actually performed was 104+/-12cpm without and 79+/-3cpm with the metronome (p<0.001). The mean compression depth during the scenario was 46.9+/-7.7mm without and 43.2+/-6.3mm with metronome guidance (p=0.09). The total number of chest compressions performed was 1022 without metronome guidance, 42% at the correct depth; and 780 with metronome guidance, 61% at the correct depth (p=0.09 for difference for percentage of compression with correct depth). CONCLUSIONS: Metronome guidance corrected chest compression rates for each compression cycle to within guideline recommendations, but did not affect chest compression quality or rescuer fatigue.

The effects of changes to the ERC resuscitation guidelines on no flow time and cardiopulmonary resuscitation quality: a randomised controlled study on manikins.

AIM OF THE STUDY: The European Resuscitation Council (ERC) guidelines changed in 2005. We investigated the impact of these changes on no flow time and on the quality of cardiopulmonary resuscitation (CPR). MATERIALS AND METHODS: Simulated cardiac arrest (CA) scenarios were managed randomly in manikins using ERC 2000 or 2005 guidelines. Pairs of paramedics/paramedic students treated 34 scenarios with 10min of continuous ventricular fibrillation. The rhythm was analysed and defibrillation shocks were delivered with a semi-automatic defibrillator, and breathing was assisted with a bag-valve-mask; no intravenous medication was given. Time factors related to human intervention and time factors related to device, rhythm analysis, charging and defibrillation were analysed for their contribution to no flow time (time without chest compression). Chest compression quality was also analysed. RESULTS: No flow time (mean+/-S.D.) was 66+/-3% of CA time with ERC 2000 and 32+/-4% with ERC 2005 guidelines (P<0.001). Human factor interventions occupied 114+/-4s (ERC 2000) versus 107+/-4s (ERC 2005) during 600-s scenarios (P=0.237). Device factor interventions took longer using ERC 2000 guidelines: 290+/-19s versus 92+/-15s (P<0.001). The total number of chest compressions was higher with ERC 2005 guidelines (808+/-92s versus 458+/-90s, P<0.001), but the quality of CPR did not differ between the groups. CONCLUSIONS: The use of a single shock sequence with guidelines 2005 has decreased the no flow time during CPR when compared with guidelines 2000 with multiple shocks.