Pad/Paddle Size and Placement in Adults: BLS and ALS SR (BLS 2601)

Conflict of Interest Declaration

The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy. The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: none applicable

The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: Ian Drennan.

CoSTR Citation

Ristagno G, Raffay V, Semeraro F, Deakin C, Drennan I, Acworth J, Morley PT, Perkins D, Smyth M, Olasveengen TM, Bray J on behalf of the International Liaison Committee on Resuscitation Basic Life Support, Advanced Life Support and Pediatric Advanced Life Support Task Forces. Pad positions and size in Adults and Children Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, November 4^th 2024. Available from: http://ilcor.org

Methodological Preamble and Link to Published Systematic Review

The continuous evidence evaluation process for the production of Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review of basic life support conducted by Giuseppe Ristagno with the involvement of clinical content experts Violetta Raffay and Federico Semeraro. A new search strategy was developed by an information specialist, and the literature was reviewed independently G. Ristagno. Evidence from adult and pediatric literature was sought and considered by the Basic Life Support, Advanced Life Support, and the Pediatric Life Support Task Forces. These data were considered when formulating the Treatment Recommendations.

Definitions:

• “Defibrillation pad” was defined as single use adhesive defibrillation pads placed on patients’ skin and connected to a defibrillator to administer an electrical shock in patients with arrhythmias, such as ventricular fibrillation or ventricular tachycardia.
• “Pad size” was defined as size of defibrillator pads.
• “Pad orientation/ position” was defined as placement of pads in various positions or orientations on the thorax to maximize effectiveness in terminating shockable cardiac rhythms.

Systematic Review

Webmaster to insert the Systematic Review citation and link to Pubmed using this format when it is available if published

Ristagno G, Raffay V, Semeraro F, Deakin C, Drennan I, Acworth J, Morley PT, Perkins D, Smyth M, Olasveengen TM, Bray J on behalf of the International Liaison Committee on Resuscitation Basic Life Support and Advanced Life Support Task Forces. Pad positions and size in Adults and Children: A systematic review. In draft.

PICOST

The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)

Population: Adults and children in any setting (in-hospital or out-of-hospital) with cardiac arrest and a shockable rhythm at any time during cardiopulmonary resuscitation (CPR)

Intervention: The use of any specific pad size/orientation and position

Comparators: Reference standard pad size/orientation and position

Outcomes: Critical: Survival with favourable neurological outcome at hospital discharge or 30-days; Survival at hospital discharge or 30 days. Important: Return of spontaneous circulation (ROSC); Termination of VF; Rates of refibrillation.

Study Designs: Randomized controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) are eligible for inclusion. Case series were included if they contained ≥ 5 cases. Unpublished studies (e.g., conference abstracts, trial protocols), animal studies, mathematical models, simulation and mannikin studies, algorithm studies with no outcome data, were excluded.

Timeframe: All years and all relevant publications in any language were included as long as there was an English abstract. Last search run on September 22^nd, 2024

PROSPERO Registration (CRD42024512443)

Consensus on Science

• Pad Positions

Out-of-hospital cardiac arrest

No RCTs were found that compared the effects of different pad positions for any critical or important outcomes outside of refractory VF/pVT (VF/pVT that persists after three consecutive defibrillation attempts). We identified two observational studies in out-of-hospital cardiac arrest (OHCA) patients. The overall certainty of evidence was rated as very low for all outcomes, primarily due to a very serious risk of bias. The individual studies were all at a critical risk of bias due to confounding. Because of this and the high degree of heterogeneity and the paucity of studies, no meta-analyses could be performed and a narrative summary of individual studies is provided.

For the critical outcome of favorable neurological outcome at hospital discharge, we identified very low certainty evidence (downgraded for very serious risk of bias and indirectness) from one observational cohort study (Lupton 2024 e2431673) by a single emergency medical services (EMS) agency. The EMS protocol recommended initial pad placement in the anterior-posterior position, if feasible, and a change to the anterior-lateral position after three consecutive failed shocks. The study, including 255 OHCA patients, found no significant benefit from the initial anterior-posterior pad position compared with the initial anterior-lateral position (34.2% vs 22.7%, adj OR 1.86 [95% CI 0.98, 3.51]; 126 more patients/1000 survived with the intervention [95% CI, 4 fewer patients/1000 to 280 more patients/1000 survived with the intervention).

For the critical outcome of survival to hospital discharge, we identified very low certainty evidence (downgraded for very serious risk of bias and indirectness) from one observational cohort study (Lupton 2024 e2431673), which found no significant benefit from the initial anterior-posterior pad position compared with intial anterior-lateral (34.2% vs 25.8%, adj OR 1.55 [95% CI 0.83, 2.90]; 92 more patients/1000 survived with the intervention [95% CI, 34 fewer patients/1000 to 244 more patients/1000 survived with the intervention).

For the important outcome of return of spontaneous circulation, we identified very low certainty evidence (downgraded for very serious risk of bias and indirectness) from one observational cohort study (Lupton 2024 e2431673), which found significant benefit from an initial anterior-posterior pad position compared with initial anterior-lateral position (74.1% vs 50.5%, adj OR 2.64 [95% CI 1.50, 4.65]; 224 more patients/1000 had ROSC with the intervention [95% CI, 100 more patients/1000 to 321 more patients/1000 had ROSC with the intervention).

For the important outcome of defibrillation success, we identified very low certainty evidence (downgraded for very serious risk of bias, serious indirectness and imprecision) from one retrospective before-after study (Steinberg 2022 16) using electronic defibrillator data recorded in OHCAs with initial VF or pulseless VT. Defibrillation success was determined retrospectively using ECG, with success defined as VF termination at 5-sec post-shock. In the pre-dataset, 207 patients received 1023 shocks with anterior-posterior pad placement (one pad placed anteriorly over the left precordium and the second pad placed inferior to the left scapula), compared with 277 patients from the post-dataset who received 1020 shocks with anterior-lateral (standard) pad placement (one pad placed under the right clavicle right to the sternum, and the second pad placed mid-axillary at the same level as the V6 ECG electrode). No difference was observed in defibrillation success between anterior-posterior and anterior-lateral pad placements (82.1 % vs 82.2 %, p = 0.99; OR 1.08 [95% CI, 0.61–1.91], p = 0.8).

Vector-change, defined as defibrillation with a new set of pads placed in the anterior-posterior position, in patients with refractory VF (i.e. persistence of VF or pulseless ventricular tachycardia (pVT) after three consecutive anterior-lateral defibrillations):

For the critical outcome of favorable neurological outcome at hospital discharge, we identified very low certainty evidence (downgraded for serious risk of bias, indirectness and very serious imprecision) from one cluster randomized controlled trial (Cheskes 2022 1947), which was stopped early due to the COVID-19 pandemic, comparing vector-change defibrillation (the anterior-posterior position) with the standard anterior-lateral defibrillation in adult patients during OHCA. The study, including 280 patients, found no significant benefit from the anterior-posterior pad position compared with anterior-lateral (16.2% vs 11.2%, adj RR 1.48 [95% CI 0.81, 2.71]; 54 more patients/1000 survived with the intervention [95% CI, 21 fewer patients/1000 to 191 more patients/1000 survived with the intervention]).

For the critical outcome of survival to hospital discharge, we identified very low certainty evidence (downgraded for serious risk of bias, indirectness and imprecision) from one cluster randomized controlled trial (Cheskes 2022 1947), which found improved survival to hospital discharge with vector change to anterior-posterior pad position compared with anterior-lateral pad position (21.7% vs 13.3%, adj RR 1.71 (95% CI 1.01, 2.88); 95 more patients/1000 survived with the intervention [95% CI, 1 more patient/1000 to 251 more patients/1000 survived with the intervention].

For the important outcome of return of spontaneous circulation (ROSC), we identified very low certainty evidence (downgraded for serious risk of bias, indirectness and very serious imprecision) from a single cluster randomized controlled trial (Cheskes 2022 1947), which found no significant improvement with vector-change to anterior-posterior pad position compared with anterior-lateral (35.4% vs 26.5%, adj RR 1.39 (95% CI 0.97, 1.99); 103 more patients/1000 survived with the intervention [95% CI, 8 fewer patients/1000 to 262 more patients/1000 survived with the intervention]).

For the important outcome of termination of ventricular fibrillation (VF) we identified very low certainty evidence (downgraded for serious risk of bias, indirectness and imprecision), from a single cluster randomized controlled trial (Cheskes 2022 1947), which found a higher rate of termination with vector-change to anterior-posterior pad position compared with anterior-lateral (79.9% vs 67.6%, adj RR 1.18 (95% CI 1.03, 1.36); 122 more patients/1000 had successful defibrillation with the intervention [95% CI, 20 more patients/1000 to 244 more patients/1000 had successful defibrillation with the intervention]).

In-hospital cardiac arrest

No studies were identified for cardiac arrest occurring in the in-hospital setting.

Pediatric cardiac arrest

No studies were identified for cardiac arrest occurring in children.

• Pad size

For the patient outcomes, no RCTs were found that compared the effects of different pad sizes to standard size for any critical or important outcomes.

For the important outcome of defibrillation success, we identified very low certainty evidence (downgraded for very serious risk of bias, and serious indirectness), from an observational pre-post implementation study (Yin 2023 109754), which found no significant difference with large pad size (113 cm2), compared with small pad size (65 cm2), (86% vs. 88.8%, OR 0.82 (95% CI 0.42, 1.60); 21 fewer patients/1000 had successful defibrillation [95% CI, 39 fewer patients/1000 to 119 more patients/1000 had successful defibrillation with the intervention]).

In-hospital cardiac arrest

No studies were identified for cardiac arrest occurring in the in-hospital setting.

Pediatric cardiac arrest

No studies were identified for cardiac arrest occurring in children.

Treatment Recommendations for adults

For defibrillator manufacturers:

There is insufficient evidence to recommend a specific pad or paddle size for optimal external defibrillation in adults (Good Practice Statement).

Manufacturers should standardize adult pad or paddle placement in the anterior-lateral position (Good Practice Statement). One pad or paddle should be placed below the right clavicle, just to the right of the upper sternal border, and the other with its center in the left mid-axillary line, below the armpit.

Manufacturers should provide clear instructions to ensure proper contact between the pad or paddle and the skin, along with diagrams that accurately show the ILCOR-recommended pad and paddle positions (Good Practice Statement).

For CPR providers using an AED:

Follow the manufacturer’s AED guidance and instructions for adult pad placement (Good Practice Statement).

For CPR providers trained in manual defibrillation:

In adults, place defibrillator pads or paddles in the anterior-lateral position to optimize placement speed and minimize interruptions to chest compressions (Good Practice Statement). One pad/paddle should be positioned below the patient’s right clavicle, just to the right of the upper sternal border. The other pad/paddle should be placed on the patient’s left mid-axillary line, below the armpit.

In adults, if the initial anterior-lateral position is not feasible, consider using the anterior-posterior pad position if trained (Good Practice Statement). Place the anterior pad on the left side of the chest, between the midline and the nipple. For female patients, place the anterior pad to the left of the lower sternum, ensuring it avoids breast tissue as much as possible. The posterior pad should be placed on the left side of the patient's spine, just below the scapula.

Pad or paddle placement should avoid breast tissue (Good Practice Statement).

For healthcare professionals trained in vector change:

For adults in refractory ventricular fibrillation (persistent VF after three defibrillations), consider changing pads to the anterior-posterior pad position (Good Practice Statement). Place the anterior pad on the left side of the chest, between the midline of the chest and the nipple. For female patients, place the anterior pad to the left of the lower sternum, ensuring it avoids breast tissue as much as possible. The posterior pad should be placed on the left side of the patient's spine, just below the scapula. This treatment recommendation does not replace the existing treatment recommendation on vector change and double sequential defibrillation for advanced life support providers (Berg 2023, e187; Berg 2023, 109992).

Justification and Evidence to Decision Framework Highlights

The ILCOR BLS and ALS Task Forces prioritized this topic because the last systematic review was performed in 2010. In 2019, the task forces re-evaluated the topic with a scoping review, followed by evidence updates in 2021 and 2022. In addition, in 2022 a cluster-randomized trial with crossover (Cheskes, 2022, 1947) evaluated, among new defibrillation strategies, vector-change defibrillation to the anterior-posterior position, compared with the standard anterior-lateral defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest (OHCA).

In making these recommendations, the task forces considered the following:

• Approximately 20% of patients remain in a shockable rhythm despite standard resuscitation interventions. Transthoracic impedance varies based on pad size and position, and this may impact shock success. Different pad orientations/positions may also result in a higher current density in different areas of the myocardium from where fibrillation may start/restart.

• No studies directly compare the effects of different pad placements on patient outcomes outside of refractory shockable rhythms.

• In clinical practice, BLS and ALS providers are unable to select pads sizes beyond what is provided by their healthcare organization. Therefore the Task Force realized that recommending the use of a specific pad size does not apply to providers.

• The four studies included were at serious risk of bias, and only one was a RCT (Cheskes, 2022, 1947).

• A secondary analysis of the DOSE VF trial (Cheskes, 2024, 110186), which explored the relationship between alternative defibrillation strategies employed and the type of VF, defined as shock-refractory VF or recurrent VF (e.g. persistent VF after each shock) or recurrent VF (e.g. absence of VF for at-least 5 sec after the shock, followed by spontaneous refibrillation), on patient outcomes, showed that vector-change defibrillation compared to standard pads placement, was not superior for VF termination, ROSC, or survival for shock-refractory VF; for recurrent VF, vector-change defibrillation was superior to standard pads placement only for VF termination, but not for ROSC or survival.

• In Yin (2023), transthoracic impedance was higher for smaller electrodes than the larger electrodes, but defibrillation success was equivalent. The study, however, has important biases in its design. It included no data on ROSC or survival and focused only on the biphasic truncated exponential defibrillation waveform. Based on the above assumptions, no evidence exists that any specific pad size/orientation and position differing from the standard anterior-lateral improves any critical or important outcome. However, defibrillator manufacturers likely have proprietary data unavailable in the public sphere.

• Two observational studies in adults (Kerber 1981 676; Yin 2023 109754) and three in children (Atkins 1994 90; Atkins 1988 914; Samson 1995 544) showed that transthoracic impedance was significantly higher with small-sized pads/paddles than large-sized pads/paddles. Lower transthoracic impedance results in higher current flow, possibly allowing for higher defibrillation success. Another observational study (Kastreva 2006 1009) evaluated transthoracic impedance in volunteers measured according to the interelectrode voltage drop obtained by passage of a low amplitude high-frequency current between the two self-adhesive electrodes in anterior-posterior and anterior-lateral positions without delivering a shock. Lower transthoracic impedance was measured in the anterior-posterior compared to the anterior-lateral position.

• An observational study included 123 cardiac arrests (Dalzell 1989 741). Pad diameters were small (8/8 cm) in 26 cardiac arrests, intermediate (8/12 cm) in 63 arrests and large (12/12 cm) in 34 cardiac arrests. Transthoracic impedance significantly decreased with increasing pad size. A single monophasic shock of 200 J (delivered energy) was successful in 8 of 26 (31%) arrests using small pads, in 40 of 63 (63%) with intermediate pads and in 28 of 34 (82%) with large pads (p=0.0003). Whether these results can be transferred to biphasic, impedance-compensated defibrillation waveforms remains unclear.

• There are no studies examining defibrillation pad size or orientation for IHCA. However, the evidence reported in this document could be applied to the IHCA, with additional downgrading for indirectness.

• Paddles may still be in use in some low-resource ALS settings. However, the Task Force acknowledges that the anterior-posterior position is not feasible with paddles and that paddle sizes are those standard as provided by the manufacturer. The Task Force did not foresee future development in the use of paddles.

• In atrial fibrillation, although some studies have shown that antero-posterior electrode placement is more effective than the traditional antero-apical position in elective cardioversion, the majority have failed to demonstrate any clear advantage of any specific electrode position. Moreover, transmyocardial current during defibrillation is likely to be maximal when the electrodes are placed so that the area of the heart that is fibrillating lies directly between them (i.e. ventricles in ventricular fibrillation/tachycardia, atria in atrial fibrillation). Therefore, the optimal electrode position may not be the same for ventricular and atrial arrhythmias and conclusions for one condition cannot be directly translated/applied to the other.

• AEDs have pictoral representation to guide providers in correct pad positioning. However, there is a wide variation in this pictoral guidance and evidence suggests that correct anatomical pad placement is poor, such that a clearer, more effective diagram is urgently needed. In a recent study, untrained bystanders failed to achieve accurate defibrillation pad placement, when guided by current defibrillation pad diagrams (Deakin 2019 282). Manufacturers of defibrillators should follow best practice, and align pad placement with ILCOR recommendations.

• In most cases, bias was assessed per comparison rather than per outcome, since there were no meaningful differences in bias across outcomes. In cases where differences in risk of bias existed between outcomes this was noted.

Knowledge Gaps

• No RCTs have compared different pad positions with standard positions in any patient population in the first three shocks.
• No RCTs compared different pad sizes in any patient population.
• No studies examined the paediatric/in-hospital setting.
• No studies have evaluated pad placement in unique populations.
• No studies evaluated the interaction between pad size and orientation.
• Only surrogate outcomes were evaluated for pads size (i.e. transthoracic impedance).

EtD: BLS 2601 Pad position and placment ETD

Tables: BLS 2601 Pad position and placment Evidence Table

^References

Atkins DL, Sirna S, Kieso R, Charbonnier F, Kerber RE. Pediatric defibrillation: importance of paddle size in determining transthoracic impedance. Pediatrics. 1988 Dec;82(6):914-8

Atkins DL, Kerber RE. Pediatric defibrillation: current flow is improved by using "adult" electrode paddles. Pediatrics. 1994;94:90-3.

Berg et al. 2023 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces. Circulation. 2023;148:e187–e280.

Berg et al. 2023 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces. Resuscitation 2023;195:109992.

Cheskes S, Verbeek PR, Drennan IR, McLeod SL, Turner L, Pinto R, Feldman M, Davis M, Vaillancourt C, Morrison LJ, Dorian P, Scales DC. Defibrillation Strategies for Refractory Ventricular Fibrillation. N Engl J Med. 2022;387:1947-1956. doi: 10.1056/NEJMoa2207304.

Cheskes S, Drennan IR, Turner L, Pandit SV, Dorian D. The impact of alternate defibrillation strategies on shock-refractory and recurrent ventricular fibrillation: A secondary analysis of the DOSE VF cluster randomized controlled trial. Resuscitation 2024; 198:110186

Dalzell GW, Cunningham SR, Anderson J, Adgey AA. Electrode pad size, transthoracic impedance and success of external ventricular defibrillation. Am J Cardiol. 1989 Oct 1;64(12):741-4. doi: 10.1016/0002-9149(89)90757-1.

Lupton JR, Newgard CG, Dennis D, Nuttall J, Sahni R, Jui J, Neth MR, Daya MR. Initial Defibrillator Pad Position and Outcomes for Shockable Out-of-Hospital Cardiac Arrest. JAMA Network Open. 2024;7(9):e2431673

Krasteva V, Matveev M, Mudrov N, Prokopova R. Transthoracic impedance study with large self-adhesive electrodes in two conventional positions for defibrillation. Physiol Meas. 2006;27:1009-22. doi: 10.1088/0967-3334/27/10/007.

Kerber RE, Grayzel J, Hoyt R, Marcus M, Kennedy J. Transthoracic resistance in human defibrillation. Influence of body weight, chest size, serial shocks, paddle size and paddle contact pressure. Circulation. 1981 Mar;63(3):676-82. doi: 10.1161/01.cir.63.3.676

Samson RA, Atkins DL, Kerber RE. Optimal size of self-adhesive preapplied electrode pads in pediatric defibrillation. Am J Cardiol. 1995 Mar 1;75(7):544-5. doi: 10.1016/s0002-9149(99)80606-7

Steinberg MF, Olsen JA, Persse D, Souders CM, Wik L. Efficacy of defibrillator pads placement during ventricular arrhythmias, a before and after analysis. Resuscitation. 2022;174:16-19. doi: 10.1016/j.resuscitation.2022.03.004

Yin RT, Taylor TG, de Graaf C, Ekkel MM, Chapman FW, Koster RW. Automated external defibrillator electrode size and termination of ventricular fibrillation in out-of-hospital cardiac arrest. Resuscitation. 2023;185:109754. doi: 10.1016/j.resuscitation.2023.109754