Intravenous adenosine as first-line prehospital management of narrow-complex tachycardias by EMS personnel without direct physician control

An Evaluation of Prehospital Adenosine Use

BACKGROUND

Adenosine has been safely used by paramedics for the treatment of stable supraventricular tachycardia since the mid-1990s. However, there continues to be variability in paramedics' ability to identify appropriate indications for adenosine administration. As the first of a planned series of studies aimed at improving the accuracy of SVT diagnosis and successful administration of adenosine by paramedics, this study details the current usage patterns of adenosine by paramedics.

METHODS

This cross-sectional retrospective study investigated adenosine use within a large northeast EMS region from January 1, 2019, through September 30, 2021. Excluding pediatric and duplicate case reports, we created a dataset containing patient age, sex, and vital signs before, during, and after adenosine administration; intravenous line location; and coded medical history from paramedic narrative documentation, including a history of atrial fibrillation, suspected arrhythmia diagnosis, and effect of adenosine. In cases with available prehospital electrocardiograms (EKGs) for review, two physicians independently coded the arrhythmia diagnosis and outcome of adenosine administration. Statistical analysis included interrater reliability with Cohen's kappa statistic.

RESULTS

One hundred eighty-three cases were included for final analysis, 84 did not have a documented EKG for review. Categorization of presenting rhythms in these cases occurred by a physician reviewing EMS narrative and documentation. Forty of these 84 cases (48%) were adjudicated as SVT likely, 32 (38%) as SVT unlikely and 12 (14%) as uncategorized due to lack of supporting documentation. Of the 99 cases with EKGs available to review, there was substantial agreement of arrhythmia diagnosis interpretation between physician reviewers (Cohen's kappa 0.77-1.0); 54 cases were adjudicated as SVT by two physician reviewers. Other identified cardiac rhythms included atrial fibrillation (16), sinus tachycardia (11), and ventricular tachycardia (2). Adenosine cardioversion occurred in 47 of the 99 cases with EKGs available for physician review (47.5%). Adenosine cardioversion was also deemed to occur in 87% (47/54) of cases when the EKG rhythm was physician adjudicated SVT.

CONCLUSIONS

This study supports the use of adenosine as a prehospital treatment for SVT while highlighting the need for continued efforts to improve paramedics' identification and management of tachyarrhythmias.

Safety and efficacy of paramedic treatment of regular supraventricular tachycardia: a randomised controlled trial

INTRODUCTION

Supraventricular tachycardias (SVTs) are a common cause of acute hospital presentations. Adenosine is an effective treatment. To date, no studies have directly compared paramedic-with hospital-delivered treatment of acute SVT with adenosine.

METHOD

Randomised controlled trial comparing the treatment of SVT and discharge by paramedics with conventional emergency department (ED)-based care. Patients were excluded if they had structural heart disease or contraindication to adenosine. Discharge time, follow-up management, costs and patient satisfaction were compared.

RESULTS

Eighty-six patients were enrolled: 44 were randomised to paramedic-delivered adenosine (PARA) and 42 to conventional care (ED). Of the 37 patients in the PARA group given adenosine, the tachycardia was successfully terminated in 81%. There was a 98% correlation between the paramedics' ECG diagnosis and that of two electrophysiologists. No patients had any documented adverse events in either group. The discharge time was lower in the PARA group than in the ED group (125 min (range 55-9513) vs 222 min (range 72-26 153); p=0.01), and this treatment strategy was more cost-effective (£282 vs £423; p=0.01). The majority of patients preferred this management approach. Being treated and discharged by paramedics did not result in the patients being less likely to receive ongoing management of their arrhythmia and cardiology follow-up.

CONCLUSIONS

Patients with SVT can effectively and safely be treated with adenosine delivered by trained paramedics. Implementation of paramedic-delivered acute SVT care has the potential to reduce healthcare costs without compromising patient care.

TRIAL REGISTRATION NUMBER

NCT02216240.

Pre-hospital management of patients with chest pain and/or dyspnoea of cardiac origin. A position paper of the Acute Cardiovascular Care Association (ACCA) of the ESC

Chest pain and acute dyspnoea are frequent causes of emergency medical services activation. The pre-hospital management of these conditions is heterogeneous across different regions of the world and Europe, as a consequence of the variety of emergency medical services and absence of specific practical guidelines. This position paper focuses on the practical aspects of the pre-hospital treatment on board and transfer of patients taken in charge by emergency medical services for chest pain and dyspnoea of suspected cardiac aetiology after the initial assessment and diagnostic work-up. The objective of the paper is to provide guidance, based on evidence, where available, or on experts’ opinions, for all emergency medical services’ health providers involved in the pre-hospital management of acute cardiovascular care.

A prehospital treat-and-release protocol for supraventricular tachycardia

Objective

Paroxysmal supraventricular tachycardia (SVT) is a common dysrhythmia treated in the prehospital setting. Emergency medical service (EMS) agencies typically require patients treated for SVT to be transported to the hospital. This retrospective cohort study evaluated the impact, paramedic adherence, and patient re-presentation rates of a treat-and-release (T+R) protocol for uncomplicated SVT.

Methods

Data were linked from the Alberta Health Services EMS electronic patient care record (EPCR) database for the City of Calgary to the Regional Emergency Department Information System (REDIS). All SVT patients treated by EMS between September 1, 2010, and September 30, 2012, were identified. Databases were queried to identify re-presentations to EMS or an emergency department (ED) within 72 hours of T+R.

Results

There were 229 confirmed SVT patient encounters, including 75 T+R events. Of these 75 T+R events, 10 (13%, 95% confidence interval [CI] [7.4, 23]) led to an EMS re-presentation within 72 hours, and 4 (5%, 95% CI [2.1, 13]) led to an ED. All re-presentations were attributed to a single individual. After excluding 15 records that were incomplete due to limitations in the EPCR platform, 43 of 60 (72%) T+R encounters met all protocol criteria for T+R.

Conclusion

The T+R protocol evaluated in this study applied to a significant proportion of patients presenting to EMS with SVT. Risk of re-presentation following T+R was low, and paramedic protocol adherence was reasonable. T+R appears to be a viable option for uncomplicated SVT in the prehospital setting.

Paramedic Identification of Electrocardiograph J-Point and ST-Segments

Introduction:

Correct identification of the J-Point and ST-segment on an electrocardiograph (ECG) is an important clinical skill for paramedics working in acute healthcare settings. The skill of ECG analysis and interpretation is known to be challenging to learn and often is a difficult concept to teach.

Objectives:

The objective of the study was to determine if undergraduate paramedic students could accurately identify ECG ST-segment elevation and J-Point location.

Methods:

A convenience sample of undergraduate paramedic students (n = 148) was provided with four enlarged ECGs (ECG1–4) that illustrated different levels, patterns, and characteristics of ST-segment elevation. Participants were asked to identify whether ST-elevation was present, and if so, height in millimeters (mm) and the correct location of the J-Point.

Results:

There were significant variations in students'accuracy with both J-Point and ST-segment determination. Eleven (10%) students correctly identified the ST-segment being present in all ECGs. Also, ECG 2 reflected 6 mm of ST-elevation; however, only one student correctly identified this. Overall the students were 0.55 mm (95% CI = 0.29–0.81 mm, range = -6.5–5.8 mm) from the J-point on the horizontal and -0.18 mm (95% CI = -0.31–0.04 mm, range = -2.8–2.3 mm) on the vertical axis.

Conclusions:

Undergraduate paramedic students recognize ST-segment elevation. However, inaccuracies occurred with measurements of ST-segment and precise location of J-Points. Errors in ECG analysis may reflect weaknesses in teaching this skill. Consideration should be given to the design of an educational program that can reliably improve performance of this skill.

Adenosine for the Treatment of PSVT in the Prehospital Arena: Efficacy of an Initial 6 mg Dosing Regimen

Objective:

To confirm the efficacy of pre-hospital administration of adenosine, using a 6 milligram (mg) initial dosing regimen, for the treatment of paroxysmal supraventricular tachycardia (PSVT).

Methods:

Urban, suburban, rural emergency medical services (EMS) system in Clark County, Washington with advanced life support (ALS) patient transports. Concurrent, paramedic Medical Incident Report (MIR) review was conducted for 102 patients receiving prehospital adenosine during a 42-month period. Patients were administered 6 mg of adenosine using an intravenous (IV) bolus followed by 10 ml of balanced salt solution flush. If the patient's rhythm remained unchanged, the dosing regimen was increased to 12 mg followed by a 10 ml flush. This was repeated once more if the rhythm remained unchanged, to a total maximum dose of 30 mg. Medical direction for administration of adenosine was in the form of standing orders rather than direct (on-line) medical control.

Results:

Seventy-four of 102 patients had PSVT as determined by physician analysis of the initial six-second electrocardiographic rhythm strip (ECG) recording. Sixty-six of these patients converted their cardiac rhythm from PSVT using adenosine; 46 (70%) converted with the initial 6 mg bolus. Fifteen patients converted after receiving the second dose (12 mg); and five patients required 30 mg.

Conclusion:

These results show that for paramedics, adenosine is an effective treatment for PSVT. An initial bolus of 6 mg converts the majority of cases. Eighty-nine percent of cases of confirmed PSVT converted with adenosine administration.

Prehospital management of acute tachyarrhythmias

Arrhythmias are commonly encountered by emergency medical services (EMS) personnel. The potential seriousness of acute symptomatic arrhythmias necessitates thorough up-to-date training of EMS personnel. The three most common acute tachyarrhythmias, not linked to cardiac arrest, that are observed outside the hospital are paroxysmal supraventricular tachycardia (PSVT), atrial fibrillation with rapid ventricular response (RAF), and perfusing ventricular tachycardia (VT). Ideally, these tachyarrhythmias should be operationally defined in a manner that simplifies, particularly for EMS providers, their diagnosis and treatment. The authors recommend referring to these rhythms as regular narrow-complex tachycardia (presumed PSVT), irregularly irregular narrow-complex tachycardia (presumed RAF), or regular wide-complex tachycardia (presumed VT or aberrantly conducted PSVT). Although the value of treatments such as cardioversion is widely understood, the benefit from others, such as lidocaine, is unclear. Current preferences, recommendations, and concerns regarding the treatment of most arrhythmias outside the hospital reflect the dichotomy that sometimes exists between available evidence and actual practice.

Two deaths after prehospital use of adenosine

Two patients in the prehospital setting died immediately after receiving adenosine for presumed supraventricular tachycardia. Both patients' cardiac rhythms were atrial fibrillation rather than supraventricular tachycardia, and their unstable conditions resulted from underlying diseases-chronic obstructive pulmonary disease and pulmonary embolism-rather than the tachycardia. Misinterpretation of the cause of tachycardia as well as the electrocardiographic findings may be responsible for adverse outcomes.

Adenosine and pediatric supraventricular tachycardia in the emergency department: multicenter study and review

STUDY OBJECTIVE

To determine the frequency of successful cardioversion and the adverse effects of adenosine treatment in pediatric emergency department patients with supraventricular tachycardia (SVT).

METHODS

This was a multicenter descriptive study with both prospective (convenience sample) and retrospective (chart review) patient entry. The setting was 7 urban pediatric EDs with a yearly census range of 22,000 to 70,000 visits. Pediatric patients 18 years of age and younger who received intravenous adenosine for presumed SVT were eligible.

RESULTS

Six investigators from 7 pediatric EDs entered 82 patients with 98 presumed SVT episodes (52 prospective and 46 retrospective) into the study. Twenty-five episodes occurred in children younger than 1 year of age. Eight patients had congenital heart disease, 59 had a history of SVT, 43 were taking cardiac medications (digoxin in 27), 13 had a history of asthma, and 25 presented in compensated cardiogenic shock. A total of 193 intravenous doses of adenosine were administered; doses were classified as low (<.1 mg/kg [n=18]), medium (.1 to <.2 mg/kg [n=116]), or high (>/=.2 mg/kg [n=59]). The dose range was.03 to.5 mg/kg, and only 2 doses were higher than.3 mg/kg. A total of 95 patient-events were determined to be SVT, all but 5 of which were atrioventricular (AV) node-dependent; 3 events were ventricular tachycardia. The overall cardioversion success rate of adenosine was 72% (71/98), and that for AV node-dependent SVT was 79% (71/90). Cardioversion was successful for 4 patient-events at a low dose, 44 at a medium dose, and 23 at a high dose of adenosine. Adverse effects occurred in 22 patients, and no patient had bronchospasm or hemodynamically significant arrhythmia.

CONCLUSION

Intravenous administration of adenosine led to successful cardioversion in 72% of pediatric ED patient-events that were presumed to be SVT. A dose range of.1 to.3 mg/kg was found to be most effective. Adenosine was not associated with significant adverse effects.

The perceived importance of paramedic skills and the emphasis they receive during EMS education programs

OBJECTIVE

The National Standard Curriculum for paramedics is currently being revised. There is little scientific evidence of what does and what does not work in prehospital care, and of whether the National Standard Curriculum prepares paramedics for the field. To provide some basis for the current revisions to the National Standard Curriculum, the authors determined which prehospital skills are perceived by paramedics to be the most important, and whether the emphasis placed on those skills during initial and continuing education programs corresponds with the perceived importance.

METHODS

Surveys listing 21 paramedic skills were mailed to the directors of 41 EMS agencies who agreed to participate in the study. The directors distributed the surveys to 1,364 paramedics affiliated with their organizations. The participants were asked to rate the importance of each skill, and the emphasis placed on each skill during their initial and continuing education. Skills were ranked on a scale of 0 to 4, with 0 representing no importance or emphasis, and 4 representing the most possible importance or emphasis.

RESULTS

Six-hundred of the 1,364 (44%) surveys were returned. Respondents had a mean of 9.9 +/- 5.6 years of EMS experience, and 5.4 +/- 4.0 years of experience as paramedics. The three skills ranked highest in importance were: 1) endotracheal intubation; 2) defibrillation; and 3) assessment. Importance in prehospital care was ranked equal to or higher than emphasis in both initial and continuing education for all skills except splinting and urinary catheterization, which received higher rankings for emphasis in initial education. Emphasis in initial education equaled or exceeded the emphasis in continuing education for all skills except intraosseous infusion.

CONCLUSION

The perceived importance of most prehospital skills is very high, and exceeds the emphasis placed on those skills during both initial and continuing education programs. These findings have implications for medical directors, EMS instructors, and persons involved with the revision of the National Standard Curriculum.

Treatment of out-of-hospital supraventricular tachycardia: adenosine vs verapamil

OBJECTIVE

To compare the use of adenosine and the use of verapamil as out-of-hospital therapy for supraventricular tachycardia (SVT).

METHODS

A period of prospective adenosine use (March 1993 to February 1994) was compared with a historical control period of verapamil use (March 1990 to February 1991) for SVT. Data were obtained for SVT patients treated in a metropolitan, fire-department-based paramedic system serving a population of approximately 1 million persons. Standard drug protocols were used and patient outcomes (i.e., conversion rates, complications, and recurrences) were monitored.

RESULTS

During the adenosine treatment period, 105 patients had SVT; 87 (83%) received adenosine, of whom 60 (69%) converted to a sinus rhythm (SR). Vagal maneuvers (VM) resulted in restoration of SR in 8 patients (7.6%). Some patients received adenosine for non-SVT rhythms: 7 sinus tachycardia, 18 atrial fibrilation, 7 wide-complex tachycardia (WCT), and 2 ventricular tachycardia; no non-SVT rhythm converted to SR and none of these patients experienced an adverse effect. Twenty-five patients were hemodynamically unstable (systolic blood pressure < 90 mm Hg), with 20 receiving drug and 13 converting to SR; 8 patients required electrical cardioversion. Four patients experienced adverse effects related to adenosine (chest pain dyspnea, prolonged bradycardia, and ventricular tachycardia). In the verapamil period, 106 patients had SVT: 52 (49%) received verapamil (p < 0.001, compared with the adenosine period), of whom 43 (88%) converted to SR (p = 0.11). Two patients received verapamil for WCT; neither converted to SR and both experienced cardiovascular collapse. VM resulted in restoration of SR in 12 patients (11.0%) (p = 0.52). Sixteen patients were hemodynamically unstable, with 5 receiving drug (p = 0.005) and 5 converting to SR; 9 patients required electrical cardioversion (p = 0.48). Four patients experienced adverse effects related to verapamil (hypotension ventricular tachycardia, ventricular fibrillation). Recurrence of SVT was noted in 2 adenosine patients and 2 verapamil patients in the out-of-hospital setting and in 23 adenosine patients and 15 verapamil patients after ED arrival, necessitating additional therapy (p = 0.48 and 0.88, for recurrence rates and types of additional therapies, respectively). Hospital diagnoses, outcomes, and ED dispositions were similar for the 2 groups.

CONCLUSION

Adenosine and verapamil were equally successful in converting out-of-hospital SVT in patients with similar etiologies responsible for the SVT. Recurrence of SVT occurred at similar rates for the 2 medications. Rhythm misidentification remains a common issue in out-of-hospital cardiac care in this emergency medical services system.