Measuring the call-receipt-to-defibrillation interval: evaluation of prehospital methods

Response Time and Causes of Delay in Prehospital Emergency Missions in Mashhad, 2015

Background: The response time is considered as one of the most important criteria for the quality of given care to the injured. This research aimed to investigate the frequency and causes of prehospital emergency delays in the 115 emergency center, in city of Mashhad, in 2015.

Methods: In this cross-sectional study, 21,142 missions performed in 2015 were investigated, from among which 640 missions with delays in systematic sampling were recognized. For data analysis purposes, descriptive statistics (frequency, mean and SD) in Excel 2013 software was implemented.

Results: Nearly 60% of the injured were men, 23% women, and the gender of 17% was not recorded in their profiles. The mean age of the injured was 29.8+15.9 years and 30% of the injured were in the age group of 16 to 25. The mean response time was 9:01+2:46. The most prevalent causes related to missions out of the operational zone (29.3%) and the second cause has been related to traffic groups (24.2%).

Conclusion: Establishing new bases and completing the number of ambulances and human recourses, intervention in traffic causing factors, and training the public about emergency cases can be effective in reducing the number of missions and the pace and quality of services provided to the injured.

Out-of-hospital cardiac arrest in high-rise buildings: delays to patient care and effect on survival

BACKGROUND

The increasing number of people living in high-rise buildings presents unique challenges to care and may cause delays for 911-initiated first responders (including paramedics and fire department personnel) responding to calls for out-of-hospital cardiac arrest. We examined the relation between floor of patient contact and survival after cardiac arrest in residential buildings.

METHODS

We conducted a retrospective observational study using data from the Toronto Regional RescuNet Epistry database for the period January 2007 to December 2012. We included all adult patients (≥ 18 yr) with out-of-hospital cardiac arrest of no obvious cause who were treated in private residences. We excluded cardiac arrests witnessed by 911-initiated first responders and those with an obvious cause. We used multivariable logistic regression to determine the effect on survival of the floor of patient contact, with adjustment for standard Utstein variables.

RESULTS

During the study period, 7842 cases of out-of-hospital cardiac arrest met the inclusion criteria, of which 5998 (76.5%) occurred below the third floor and 1844 (23.5%) occurred on the third floor or higher. Survival was greater on the lower floors (4.2% v. 2.6%, p = 0.002). Lower adjusted survival to hospital discharge was independently associated with higher floor of patient contact, older age, male sex and longer 911 response time. In an analysis by floor, survival was 0.9% above floor 16 (i.e., below the 1% threshold for futility), and there were no survivors above the 25th floor.

INTERPRETATION

In high-rise buildings, the survival rate after out-of-hospital cardiac arrest was lower for patients residing on higher floors. Interventions aimed at shortening response times to treatment of cardiac arrest in high-rise buildings may increase survival.

The evaluation of time performance in the emergency response center to provide pre-hospital emergency services in Kermanshah

This study evaluated the time performance in the emergency response center to provide pre-hospital emergency services in Kermanshah. This study was a descriptive retrospective cross-sectional study. In this study 500 cases of patients from Shahrivar (September) 2012 to the end of Shahrivar (September) 2013 were selected and studied by the non-probability quota method. The measuring tool included a preset cases record sheet and sampling method was completing the cases record sheet by referring to the patients’ cases. Data were analyzed using SPSS version 18 and the concepts of descriptive and inferential statistics (Kruskal-Wallis test, benchmark Eta (Eta), Games-Howell post hoc test). The results showed that the interval mean between receiving the mission to reaching the scene, between reaching the scene to moving from the scene, and between moving from the scene to a health center was 7.28, 16.73 and 7.28 minutes. The overall mean of time performance from the scene to the health center was 11.34 minutes. Any intervention in order to speed up service delivery, reduce response times, ambulance equipment and facilities required for accuracy, validity and reliability of the data recorded in the emergency dispatch department, Continuing Education of ambulance staffs, the use of manpower with higher specialize levels such as nurses, supply the job satisfaction, and increase the coordination with other departments that are somehow involved in this process can provide the ground for reducing the loss and disability resulting from traffic accidents.

MEASURING THE EMS PATIENT ACCESS TIME INTERVAL andTHE IMPACT OF RESPONDING TO HIGH-RISE BUILDINGS

OBJECTIVES

To measure the patient access time interval and characterize its contribution to the total emergency medical services (EMS) response time interval; to compare the patient access time intervals for patients located three or more floors above ground with those less than three floors above or below ground, and specifically in the apartment subgroup; and to identify barriers that significantly impede EMS access to patients in high-rise apartments.

METHODS

An observational study of all patients treated by an emergency medical technician paramedics (EMT-P) crew was conducted using a trained independent observer to collect time intervals and identify potential barriers to access.

RESULTS

Of 118 observed calls, 25 (21%) originated from patients three or more floors above ground. The overall median and 90th percentile (95% confidence interval) patient access time intervals were 1.61 (1.27, 1.91) and 3.47 (3.08, 4.05) minutes, respectively. The median interval was 2.73 (2.22, 3.03) minutes among calls from patients located three or more stories above ground compared with 1.25 (1.07, 1.55) minutes among those at lower levels. The patient access time interval represented 23.5% of the total EMS response time interval among calls originating less than three floors above or below ground and 32.2% of those located three or more stories above ground. The most frequently encountered barriers to access included security code entry requirements, lack of directional signs, and inability to fit the stretcher into the elevator.

CONCLUSIONS

The patient access time interval is significantly long and represents a substantial component of the total EMS response time interval, especially among ambulance calls originating three or more floors above ground. A number of barriers appear to contribute to delayed paramedic access.

Transmural optical measurements of Vm dynamics during long-duration ventricular fibrillation in canine hearts

BACKGROUND

Knowledge of transmural V(m) changes is important for understanding the mechanism of long-duration ventricular fibrillation (LDVF).

OBJECTIVE

The purpose of this study was to measure transmural V(m) changes during LDVF.

METHODS

V(m) was recorded optically at up to 8 transmural points separated by 1.5 mm in the left ventricle of Langendorff-perfused canine hearts (n = 6) using a bundle of optical fibers (optrode) during 10 minutes of LDVF followed by 3 minutes of VF with reperfusion. Measurements were grouped into 4 layers: epicardium, subepicardium, midwall, and subendocardium.

RESULTS

Activation rates (ARs) and action potential durations (APDs) decreased, whereas diastolic intervals (DIs) increased during LDVF in all transmural layers (P < .05). After approximately 3 minutes of LDVF, ARs were faster and DIs shorter in the midwall and subendocardium than in the epicardium and subepicardium (P < .05). Activations persisted at the subendocardium but disappeared from other layers after approximately 8 minutes of VF in the majority of hearts. There were no transmural differences in APD during LDVF or during pacing before and after LDVF (P > .05). Restitution plots showed no functional relationship between APD and DI in any layer at any stage of LDVF. Partial reperfusion during VF for 3 minutes restored transmural synchronicity of activation and eliminated gradients in activation parameters.

CONCLUSION

V(m) dynamics evolve differently at different transmural layers. The subendocardium maintains persistent and the fastest activation during 10 minutes of LDVF, suggesting it contains the source of VF wavefronts. There are no transmural APD gradients and no restitution relationship between APD and DI at any transmural layer, indicating these are not the primary factors in the mechanism of LDVF.

Time matters; what is the time in your defibrillator? An observational study in 30 emergency medical service systems

BACKGROUND

Measuring different intervals during cardiopulmonary resuscitation is a key element of resuscitation performance. For accurate time measurements, the internal clocks of automated external defibrillator (AEDs) need to be synchronized with the dispatch centre time.

AIM

To determine the present practice of using and synchronizing the AED clocks in five regions in Finland.

METHODS

During a single morning, the time of all AED clocks in the emergency medical service (EMS) systems of five large hospital districts were checked and compared with the dispatch centre time. A questionnaire about synchronisation policy and documentation of the first defibrillatory shock was also e-mailed to the local EMS medical supervisors.

RESULTS

Eighty-eight AEDs were checked in 30 EMS systems. The mean deviation from dispatch centre time was 412 (+/-1001) s. There was no difference between EMS systems with (N = 7) or without (N = 23) written guidelines regarding synchronisation. Many EMSs reported that they document the time of the first shock without synchronisation of clocks.

CONCLUSIONS

Synchronisation of AED clocks is not widespread in Finland. Instructions to synchronize have been issued in a minority of EMS systems. Despite this, time deviations are large, and erroneous times are recorded.

[Evaluation of duration for direct admission dispatch process in an urban area]

OBJECTIVE

In France, when physicians in ambulances take care of patients, they report medical status to the dispatch centre. Then the dispatching physician search for the available and appropriate hospital service to agree in directly receiving the patient. We attempted to evaluate this direct admission dispatch, in a urban area, with many health care facilities.

STUDY DESIGN

Prospective evaluation.

PATIENTS AND METHODS

All the files for out of hospital interventions with a dispatch process were included. Data collected and analysed were: main pathologies, started time and end time of direct admission dispatch process and number of services called before finding the right place.

RESULTS

959 patients files were included, 849 could be analysed. The average duration of direct admission dispatch process is 10 (+/-13) minutes. Traumatology speciality shows a longer dispatch process than medicine disease (p < 0.001), and this time increased during summer (p < 0.05). The other parameters did not influence this duration.

CONCLUSION

The average duration of direct admission dispatch process is acceptable. The increased duration of direct admission dispatch process in some pathology during summer may induce a risk for the patients. This problem will be improved only when the management of the available bed for emergency traumatology, will be implemented a regional coordination.

Ambulance, fire, and police dispatch times compared with the atomic clock

OBJECTIVES

To quantify any differences between the times used by public safety answering points (PSAPs) in a multijurisdictional county compared with the atomic clock and to determine whether there was consistency in any time differences.

METHODS

All 25 ambulance, fire, and police PSAPs were contacted by telephone. The current time in hours, minutes, and seconds on the dispatch center's timepiece was requested. The atomic clock time was simultaneously recorded. Time differences between the reported and atomic clock times were calculated and the absolute values were used to calculate the mean difference. The procedure was repeated one week later. Consistency in time deviation was evaluated by subtracting the time differences between weeks 1 and 2 for each center.

RESULTS

All 25 centers were contacted and three declined to participate. Time differences ranged from -551 to 117 seconds (mean difference: 61.2 +/- 120.3) for week 1 and -103 to 79 seconds (mean difference: 36.9 +/- 33.4) for week 2. Time deviations between weeks 1 and 2 were: 0 seconds for one center, 1 to 30 seconds for 12 centers, 31 to 60 seconds for four centers, and more than 60 seconds for five centers.

CONCLUSIONS

The maximum time difference between dispatch center and atomic clock times was 551 seconds. This difference may be clinically significant for time-dependent research, quality improvement tasks, or medical legal reviews when multiple PSAPs are involved. Lack of consistency in time deviation over one week suggests systematic adjustment for these differences may not be possible.

Actual vs perceived EMS response time

OBJECTIVE

To compare patients' perceptions of ambulance response times with the actual ambulance response times to aid quality assurance efforts in EMS management.

METHODS

A convenience sample of patients presenting to an urban ED via EMS were asked a series of four questions pertaining to response time, scene time, time to definitive care, and their expectations of response time. These times were then compared with actual times from the EMS dispatch center. Times were analyzed using multivariate analysis of variance (MANOVA) followed by discriminant analysis.

RESULTS

There was a significant difference between the perceived and actual times for all three questions, by both multivariate analysis and univariate analysis (p < 0.0001). Patients tended to overestimate the actual response times (12.4 min vs 9.1 min) but underestimate the on-scene times (9.1 min vs 12.4 min) and times to definitive care (29.4 min vs 35.0 min).

CONCLUSION

Patients are inaccurate in their estimations of time. Response times are generally overestimated, while scene times and times to definitive care are underestimated. Actual response times often meet patients' expectations (mean 10.8 min), although the patients may not perceive that they have.

Measuring response intervals in a system with a 911 primary and an emergency medical services secondary public safety answering point

STUDY OBJECTIVE

Measurement of interval data is important in the accurate recording of events that occur in an emergency medical services system. Measurement of intervals should be a simple task. However, when two separate clocks are needed to record the beginning and end of an interval, accurate measurement may be difficult. We sought to accurately measure the 911 call receipt-to-vehicle departure and 911 calls receipt-to-patient access intervals in a system with primary and secondary public safety answering points (PSAPs).

METHODS

We conducted a descriptive study between January 1 and July 31, 1993. All 911 calls beginning at the primary PSAP, transferred to the EMS secondary PSAP, and ending with patient access times were eligible. Clock-synchronization errors and unavailability of 911 time logs were the criteria for exclusion. We measured the 911 call receipt-to-vehicle departure interval by adding the primary-PSAP and the EMS secondary-PSAP call-processing intervals. The 911 call receipt-to-patient access interval was the absolute difference between the time when the 911 primary-PSAP phone range and the time of patient access recorded by EMS personnel.

RESULTS

The data were best described with median and interquartile ranges (IQRs). We found 1,945 calls that met inclusion criteria. Of these, 270 were deleted because of clock errors and 616 for time log unavailability, yielding 1,059 calls for interval determinations. The median 911 call receipt-to-vehicle departure interval was 1.7 minutes (IQR, 1.2 to 2.2 minutes). The median 911 call receipt-to-patient access interval was 8.2 minutes (IQR, 6.4 to 10.5 minutes).

CONCLUSION

The 911 call receipt-to-vehicle departure and 911 call receipt-to-patient access intervals can be accurately measured in a system with two separate PSAP computer-aided dispatch clocks. These intervals are variable and often lengthy.

Predicting survival from out-of-hospital cardiac arrest: a multivariate analysis

From 954 attempts to resuscitate patients from out-of-hospital cardiac arrest two datasets were derived, namely 861 cases of cardiac arrest and 906 cases of either cardiac or primary respiratory arrest. For each dataset, multivariate analysis was performed by fitting a number of explanatory variables with respect to the outcomes of admission to hospital and discharge home in logistic regression models. There were numerous interactions between these variables. Being conscious at the time of the arrival of the ambulance crew and subsequently having cardiac arrest strongly predicted survival, as did both the presence of a witness to the arrest and the initiation of cardiopulmonary resuscitation (CPR) by a bystander; this latter effect was a marker for early CPR. The strongest predictor of a poor outcome was delay to CPR or delay to advanced cardiac life support.