Paddle/pad Size and Placement in infants and children: PLS 4080.17 Updated Systematic Review

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

Lopez-Herce J, del Casillo J, Ristagno G, Raffay V, Semeraro F, Deakin C, Drennan I, Acworth J, Morley PT, Perkins D, Smyth M, Olasveengen TM, , Scholefield B, De Caen A, Bray J on behalf of the International Liaison Committee on Resuscitation Basic Life Support Task Force(s).

Pad positions and size in Adults and Children Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Pediatric Life Support Task Force, 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

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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 pending (number CRD42024512443)

Consensus on Science

• Pad Positions

Out-of-hospital cardiac arrest

No studies in infants and children were identified.

In adult population, 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 3 consecutive defibrillation attempts). We identified one observational study in OHCA patients (3). The overall certainty of evidence was rated as very low for all outcomes, primarily due to a very serious risk of bias and indirectness of evidence. 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 serious and serious indirectness) from one observational cohort study (1) by a single emergency medical services agency. Agency protocol recommended initial pad placement in the anterior-posterior position if feasible and the change to the anterior-lateral position after 3 consecutive failed shocks. The study, including 255 patients, found no significant benefit from the intial anterior-posterior pad position compared with intial anterior-lateral (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 serious indirectness) from one observational cohort study (1), which found no significant benefit from the intial 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 serious indirectness) from one observational cohort study(1), which found significant benefit from the intial anterior-posterior pad position compared with intial anterior-lateral (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, very serious indirectness and imprecision) from one retrospective before-after study(2) on 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 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 standard defibrillations:

No studies in infants and children were identified.

For the critical outcome of favorable neurological outcome at hospital discharge, we identified very low certainty evidence (downgraded for serious risk of bias, very serious indirectness and very serious imprecision) from one cluster randomized controlled trial (3), which was stopped early due to the COVID-19 pandemics, comparing vector-change defibrillation (the anterior-posterior position) with the standard anterior-lateral defibrillation in adult patients during out-of-hospital cardiac arrest (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, very serious indirectness and imprecision) from one cluster randomized controlled trial (3), 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, very serious indirectness and very serious imprecision) from a single cluster randomized controlled trial (3), 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, very serious indirectness and imprecision), from a single cluster randomized controlled trial (3), which found a higher rate of termination of 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 survived with the intervention [95% CI, 20 more patients/1000 to 244 more patients/1000 survived with the intervention]).

In-hospital cardiac arrest

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

• Pad size

No RCTs were found that compared the effects of different pad size to standard size on 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 indirectness), from an observational pre-post implementation study(4), 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 survived with the intervention [95% CI, 39 fewer patients/1000 to 119 more patients/1000 survived with the intervention]).

In-hospital cardiac arrest

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

Treatment Recommendations

For manufacturers:

Manufacters could consider the standardization of pads size for infants, children and adults. (Good Practice Statement).

Manufacturers of AEDs should standardize pad placement in an anterior-posterior

position for infants and young children (with one pad anteriorly, over the left precordium, and

the other pad posteriorly to the heart just inferior to the left scapula) (Good Practice Statement).

Manufacturers should include instructions to ensure adequate contact between the pad and the skin and ensure that their pads position diagrams clearly indicate the ILCOR recommended pad position (Good Practice Statement).

For CPR providers using an AED:

Follow the AED's specific guidance and instructions for pads placement in infants and children (Good practice statement).

For CPR providers trained in manual defibrillation:

In infants and children place pads in an anterior-posterior position as described above (Good practice statement).

Vector change strategy:

We cannot make a recommendation for or against the use of vectorial change strategy for the treatment of refractory VF or pulseless VT in infants and children.

Justification and Evidence to Decision Framework Highlights

Due to the lack of direct evidence in infants and children post-cardiac arrest, and very low certainty of the indirect evidence from adults, the Task Force was unable to make treatment recommendations for CPR providers using both AEDs and manual defibrillators. The Task Force decision to provide a Good Practice Statement suggesting pads positioning in AP position was based on the indirect evidence on adults that it improves ROSC. However, the Task Force did recognize the very low certainty of the evidence from this observational study.

In making these recommendations, the PLS Task Force considered the following:

• Pulseless shockable rhythms are more common in adults than in infants and children and vary according to the age. The low frequency of these rhythms contributes to the lack of information on pediatric defibrillation. We do not know the incidence of refractory shockable rhythms in infants and children.

• 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 voltage gradient in different areas of the myocardium from where fibrillation may start/restart.

• The four studies included were all adults studies and at serious risk of bias, and only one was a RCT (3).

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

• A secondary analysis of the DOSE VF trial (5) , which explored the relationship between alternative defibrillation strategies employed and the type of VF, i.e. shock-refractory VF or recurrent VF, 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 (4), 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, there is no evidence that any specific pad size/orientation and position differing from the standard anterior-lateral improves any critical or important outcome. However, it is likely that defibrillator manufacturers have proprietary data that are not available in the public sphere.

• Two observational studies in adults (4) (6) and three in infants and children (7) (8) (9) 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 (10)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(11). 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 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).

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

• Paddles may still be in use in some low-resource 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 pediatric resuscitation, pads are also used as real-time feedback devices for quality assessment of chest compressions. For chest compression metric measurement pads are generally needed to be positioned in AP.

• Anterio-posterior positioning of pads is easier in infants and children than in adults.
• If the same pads size could be used for adult, children and infants, costs would be reduced and training could be improved.

• AEDs have pictoral representation to guide providers in correct pad positioning. Most AEDs for pediatric patients depict AP positioning. However, there is a wide variation in this recommendations and evidence suggests that correct anatomical pad placement is poor, such that a clearer, more effective diagram is urgently needed. In a recent study in adults, untrained bystanders failed to achieve accurate defibrillation pad placement, when guided by current defibrillation pad diagrams (12).

• In pediatric populations, the incidence of refractory VF or p-VT is unknown. The possibility of fitting two sets of pads in the child’s thorax could be difficult, thus making a vector change strategy impossible.

• 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 studies examined the paediatric/in-hospital setting.
• No RCTs have compared different pad positions with standard positions in any patient population, in the first 3 shocks.
• No RCTs compared different pad sizes in any patient population.
• No studies have evaluated pad placement in unique populations.
• No studies evaluated the interaction between pad size and orientation.
• No pediatric studies evaluated vector change strategy..
• Only surrogate outcomes were evaluated for pads size (i.e. transthoracic impedance).

ETD summary table: PLS 4080 17 Et D tables pads size and placement

References

1. Lupton JR, Newgard CD, Dennis D, Nuttall J, Sahni R, Jui J, et al. Initial Defibrillator Pad Position and Outcomes for Shockable Out-of-Hospital Cardiac Arrest. JAMA Netw Open. 2024;7(9):e2431673.

2. 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;174:16-9.

3. Cheskes S, Verbeek PR, Drennan IR, McLeod SL, Turner L, Pinto R, et al. Defibrillation Strategies for Refractory Ventricular Fibrillation. N Engl J Med. 2022;387(21):1947-56.

4. 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.

5. Cheskes S, Drennan IR, Turner L, Pandit SV, Dorian P. 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.

6. 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;63(3):676-82.

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

8. Atkins DL, Kerber RE. Pediatric defibrillation: current flow is improved by using "adult" electrode paddles. Pediatrics. 1994;94(1):90-3.

9. Samson RA, Atkins DL, Kerber RE. Optimal size of self-adhesive preapplied electrode pads in pediatric defibrillation. Am J Cardiol. 1995;75(7):544-5.

10. 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(10):1009-22.

11. Dalzell GW, Cunningham SR, Anderson J, Adgey AA. Electrode pad size, transthoracic impedance and success of external ventricular defibrillation. Am J Cardiol. 1989;64(12):741-4.

12. Foster AG, Deakin CD. Accuracy of instructional diagrams for automated external defibrillator pad positioning. Resuscitation. 2019;139:282-8.