Impact of transport on CPR quality: BLS 1509a

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: (none applicable)

CoSTR Citation

Smyth M, Smith C, Ristagno G, Bray J, Chung S, Dainty K, Folke F, Ikeyama T, Johnsen N, Kudenchuck P, Lagina A, Malta-Hansen C, Masterson S, Nehme Z, Nishiyama C, Norii T, Perkins GD, Vaillancourt C, Olasveengen TM, Morley PT -on behalf of the International Liaison Committee on Resuscitation Basic Life Support Task Force. Impact of ambulance transport on quality of cardiopulmonary resuscitation

Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, 2022 Jan 30th. Available from: http://ilcor.org

Methodological Preamble

The continuous evidence evaluation process for the production of Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review of CPR during transport by Smyth, Smith, Ristagno and Olasveengen with involvement of clinical content experts. Evidence was sought and considered by the Basic Life Support Task Force. These data were taken into account when formulating the Treatment Recommendations.

PICOST

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

Population: Adults and children receiving CPR following out of hospital cardiac arrest

Intervention: Transport with ongoing CPR

Comparison: Completing CPR on scene

Outcomes: Quality of CPR metrics on scene versus during transport (reported outcomes may include rate of chest compressions, depth of chest compressions, chest compression fraction, interruptions to chest compressions, leaning/incomplete release, rate of ventilation, volume of ventilation, duration of ventilation, pressure of ventilation)

Study Design: 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. Unpublished studies (e.g., conference abstracts, trial protocols) are excluded.

Timeframe: All years and all languages are included as long as there is an English abstract

PROSPERO Registration CRD42021240615

Consensus on Science

Identified studies included observational studies performed human subjects as well as randomised controlled trials and observational studies performed on manikins. Evidence is presented grouped by the following domains:

1. Impact of transport on correct hand positioning
2. Impact of transport on chest compression rate
3. Impact of transport on chest compression depth
4. Impact of transport on pauses
5. Impact of transport on leaning/incomplete release
6. Impact of transport on chest compression fraction/hands-off time
7. Impact of transport on ventilation
8. Impact of transport on overall correct CPR

1. Impact of transport on correct hand positioning

We identified very low certainty evidence, from two randomised controlled trials^{1, 2}, addressing correct hand positioning, using a manikin during simulated helicopter rescue. In one study,¹ there was no difference in the proportion of compressions where hands were placed at the correct landmark, whether at scene, in transit in an ambulance, or during flight by helicopter. In the other study,² in the before-flight phase, the mean (SD) number of compressions delivered was 508 ( 58) (95%CI 483-533). Of these compressions, 426 ( 88) (95%CI 389-464) were delivered at the correct anatomical landmark, suggesting correct hand placement for 83.9% (95%CI 80.5%-87.1%) of compressions. During the in-flight phase, the mean (SD) number of compressions delivered was 909 ( 44) (95%CI 890-928). Of these compressions, 539 ( 200) (95%CI 453-625) were delivered at the correct anatomical landmark, suggesting correct hand placement for 59.3% (95%CI 50.9%-67.3%) of compressions. Although the proportion of compressions delivered at the correct anatomical landmark was lower during transport the authors acknowledge that the cramped aircraft conditions may have been contributing factor.

1. Impact of transport on chest compression rate

We identified very low certainty evidence, from five observational studies^3-7, addressing manual chest compression rate at scene and during transport, following out of hospital cardiac arrest. These studies were undertaken over two decades during which the recommended compression rate target changed from 100 compressions per minute⁸ to 100-120 compressions per minute.⁹ Three of these studies ^3-5 reported no significant difference in chest compression rate on scene versus during transport. One study⁷ identified a statistically significant difference between chest compression rate at scene (median rate (IQR) 105.7 (12.0)) versus during transport (median rate (IQR) 102.0 (12.5)). Both of these median chest compression rates fall within the target range for high quality CPR, however the interquartile range suggests more patients received chest compression rates less than 100 compressions per minute during transport One study ⁶ reported that compression rate was poor both at scene (median (IQR)% correct compression rate 45.8% (49.8%)) and during transport (median (IQR)% correct compression rate 11.5% (39.3%)), however it is unclear how significantly under- or over-target chest compression rate EMS providers were. Two of the above studies^{5, 7} further reported that there was increased variation in chest compression rate during transport compared with resuscitation on scene.

We identified very low certainty evidence, from two randomised controlled trials^{1, 10}, addressing chest compression rate, in simulations using manikins. In one study¹ there was no significant difference in compression rate whether at scene, in transit in an ambulance or during flight by helicopter. Another study ¹⁰ reported the median (IQR) compression rate was 103 (95, 108) at scene, 95 (93, 103) moving horizontally, 86 (75, 96) descending a staircase and 106 (101, 114) during ambulance transport suggesting compression rate is equivalent at scene and during transport. A statistically significant difference (p<0.05) was confirmed during descent of the staircase compared with during other transport phases.

We identified very low certainty evidence, from two observational studies ^{11, 12} addressing chest compression rate, during simulated ski slope rescue using manikins. They compared CPR quality while stationary and during transport. One study¹¹ reported no statistically significant difference in chest compression rate when not moving (mean compression rate (95%CI) 107.5 (100.7, 114.3) and while moving (101.7 (101.7, 101.7)). The other¹² did note a statistically significant difference in mean compression rates (110.7 at scene versus 116.7 while moving), however both of these rates fall withing the target range for chest compression rate.

1. Impact of transport on chest compression depth

We identified very low certainty evidence, from four observational studies^4-7, addressing depth of manual chest compressions at scene and during transport, following out of hospital cardiac arrest. Two studies^{4, 5} reported no significant difference between chest compression depth at scene versus during transport phases. One study⁷ identified a statistically significant difference between chest compression depth at scene (median depth (IQR) 5.33cm (1.39cm)) versus during transport (median depth (IQR) 5.56cm (1.49cm)), however both of these fall within the target compression depth range for high quality CPR. One study⁶ reported a difference in chest compression depth at scene median (IQR) % correct depth of 48.3% (61.0%), versus during transport 9.8% (54.8%). It is unclear if chest compression depths in this latter study were too shallow or too deep.

We identified very low certainty evidence from two randomised controlled trials ^{1, 10} addressing chest compression depth during simulated resuscitation using manikins. One study¹ compared chest compression depth at scene, during ambulance transport and during helicopter transport. They reported that there was no significant difference in compression depth at scene (median (IQR) depth 3.7cm (3.5cm, 4.0cm) versus in transit in an ambulance (median depth 3.6cm (3.2cm, 3.8cm), however a statistcially significant difference was noted for helicopter transport (median depth 3.3cm (2.9cm, 3.5cm)). The other study ¹⁰ compared chest compression depth at scene, during extrication along a corridor, then down a flight of stairs followed by ambulance transport. They reported the median (IQR) correct compression depth was 68% (14%, 82%) on scene, 57% (45%, 66%) moving horizontally, 32% (6%, 59%) descending a staircase and 66% (62%, 77%) during ambulance transport suggesting compression depth is equivalent on scene and during transport. A significant difference in chest compression depth was identified during descent of the staircase when the proportion (median (IQR)) of shallow compressions was 68% (28%, 95%).

We identified very low certainty evidence from two observational studies ^{11, 12} addressing depth of chest compressions during simulated ski slope rescue (sledge towed behind a skimobile) using manikins. One of the studies¹¹ reported no statistical difference in chest compression depth at scene versus during transport. Mean compression depth (95%CI) at scene 52.6mm (48.4mm, 56.6mm) and while moving 52.2mm (51.5mm, 52.8mm). The other¹² did note a statistically significant difference in mean compression depth (5.64cm at scene versus 5.02cm while moving), however both of these depths fall within the target range for chest compressions.

1. Impact of transport on pauses in chest compressions

We identified very low certainty evidence from one observbational study¹², using a manikin during simulated ski-slope rescue, addressing pauses in chest compressions. The authors reported that all pauses in chest compressions, both at scene and during movement, were under 10 seconds, as recommended by international resuscitation guidelines.

1. Impact of transport on leaning/incomplete release

We identified very low certainty evidence, from one randomised controlled trial², addressing leaning/incomplete release, during simulated helicopter rescue using a manikin. For manual CPR, in the before-flight phase the mean (SD) number of compressions delivered was 508 (58) (95%CI 483-533). Of these compressions, 476 (90) (95%CI 437-515) had complete release suggesting paramedics achieved complete release for 93.7% (95%CI 90.5%-96.6%) of compressions. During the in-flight phase the mean (SD) number of compressions delivered was 909 (44) (95%CI 890-928). Of these compressions, 894 (75) (95%CI 862-927) had complete release suggesting paramedics achieved complete release for 98.3% (95%CI 96.6%-96.9%) of compressions.

We identified very low certainty evidence, from one observational study¹², addressing leaning/incomplete release, during simulated ski slope rescue utilising an manikin. The authors¹² reported no difference in chest recoil while at scene (mean (SD) % 86% (28.3)) or while moving (mean (SD) % 81% (21.4)).

1. Impact of transport on chest compression fraction/hands-off time

We identified very low certainty evidence, from four observational studies^{3-5, 7}, addressing chest compression fraction/hands-off time at scene and during transport, following out of hospital cardiac arrest. One study⁵ reported no significant difference in chest compression fraction (proportion of time with chest compressions) at scene (60.6 ± 16.0) versus during transport (65.7 ± 19.5). Two studies ^{3, 4} reported a significant difference in no-flow ratio (proportion of time without chest compressions) when at scene: 0.51 (95%CI 0.48, 0.54) versus during transport 0.48 (95%CI 0.44, 0.51), p<0.05) and in hands-off ratio (proportion of time without chest compressions) when at scene mean 0.19 (SD 0.09) versus during transport mean 0.27 (SD 15) respectively. One study ⁷ reported a significant difference in chest compression fraction (proportion of time with chest compressions) when at scene median 0.86 (IQR 0.12)) versus during egress median 0.87 (IQR 0.20) versus during transport 0.95 (IQR 0.08), p<0.01).

We identified very low certainty evidence, from one randomised controlled cross-over trial¹, addressing chest compression fraction/hands-off time, during simulated helicopter rescue utilising a manikin. They reported no statistically significant difference in time without chest compression when comparing resuscitation at scene, during ambulance transport and helicopter transport.

We identified very low certainty evidence, from one observational study¹², addressing chest compression fraction/hands-off time, during simulated ski slope rescue using manikins. The authors adopted chest compression only model and reported a significant difference (p=0.002) in chest compression fraction when comparing stationary (median 100%, range 99-100%) and moving phases (median 97.5%, range 74-100%).

1. Impact of transport on ventilation

We identified very low certainty evidence, from two observational studies^{3, 4}, addressing ventilation rate at scene and during transport, following out of hospital cardiac arrest. One of these studies³ reported no significant difference between ventilation rates at scene (mean 13 bpm (SD 4 bpm)) versus during transport (mean 14 bpm (SD 3 bpm)). The other ⁴ identified a significant difference between ventilation rates at scene (mean 10 bpm (95%CI 9, 11)) versus during transport (mean 15 bpm (95%CI 12, 18)).

1. Impact of transport of overall correct compressions

We identified very low certainty evidence, from one observational study⁷, addressing overall proportion of correct chest compressions at scene and during transport, following out of hospital cardiac arrest. Cheskes et al reported that high quality CPR (chest compression rate 100-120 bpm, chest compression depth 50mm, chest compression fraction 0.8) was achieved in 209 of 842 cases (24.8%) at scene, while during transport these criteria were achieved in 180 cases (21.4%). The proportion of correct compressions is below guideline recommendations both at scene and during transport. It is unclear if these lower than expected proportions are clinically significant, however the difference was not statistically significant.

We identified very low certainty evidence, from one observational study¹³, addressing overall proportion of correct chest compressions, during simulated resuscitation at scene and during transport. Stone et al reported a mean correct percentage of correct chest compressions by EMS providers was 77.6% in a stable environment and 45.6% in a moving ambulance.

Treatment Recommendations

Quality of manual CPR may be reduced during transport. We recommend that whenever transport is indicated EMS providers should focus upon delivery of high quality CPR throughout transport (strong recommendation, very low certainty evidence).

Delivery of manual CPR during transport increases the risk of injury to providers. We recommend that EMS systems have a responsibility to assess this risk and, where practicable, to implement measures to mitigate the risk (Good Practice Statement).

Justification and Evidence to Decision Framework Highlights

A scoping review was completed for the 2020 Consensus on Science and Treatment recommendations. This topic was prioritized by the BLS Task Force.

The decision to transport or remain on scene is complex. Considerations may include patient factors (age, comorbidities), clinical considerations (scope of practice of providers, aetiology, rhythm, response to treatment), logistical considerations (location of arrest, challenges of extrication, resources required, journey to hospital), patient and provider safety considerations, and hospital capability (ECMO or other advanced interventions).

There is limited low certainty evidence that can broadly be summarized as follows:

Knowledge Gaps

• There are a limited number of small human studies
• There were no studies in the paediatric population
• There were no studies that addressed the impact of CPR quality during transport on patient outcomes

Attachments

BLS 1509 Impact of transport on CPR Et D

References

References listed alphabetically by first author last name in this citation format (Circulation)

1. Havel C, Schreiber W, Riedmuller E, Haugk M, Richling N, Trimmel H, Malzer R, Sterz F and Herkner H. Quality of closed chest compression in ambulance vehicles, flying helicopters and at the scene. Resuscitation. 2007;73:264-70.

2. Putzer G, Braun P, Zimmermann A, Pedross F, Strapazzon G, Brugger H and Paal P. LUCAS compared to manual cardiopulmonary resuscitation is more effective during helicopter rescue-a prospective, randomized, cross-over manikin study. Am J Emerg Med. 2013;31:384-9.

3. Olasveengen TM, Wik L and Steen PA. Quality of cardiopulmonary resuscitation before and during transport in out-of-hospital cardiac arrest. Resuscitation. 2008;76:185-90.

4. Odegaard S, Olasveengen T, Steen PA and Kramer-Johansen J. The effect of transport on quality of cardiopulmonary resuscitation in out-of-hospital cardiac arrest. Resuscitation. 2009;80:843-8.

5. Roosa JR, Vadeboncoeur TF, Dommer PB, Panchal AR, Venuti M, Smith G, Silver A, Mullins M, Spaite D and Bobrow BJ. CPR variability during ground ambulance transport of patients in cardiac arrest. Resuscitation. 2013;84:592-5.

6. Russi CS, Myers LA, Kolb LJ, Lohse CM, Hess EP and White RD. A Comparison of Chest Compression Quality Delivered During On-Scene and Ground Transport Cardiopulmonary Resuscitation. West J Emerg Med. 2016;17:634-9.

7. Cheskes S, Byers A, Zhan C, Verbeek PR, Ko D, Drennan IR, Buick JE, Brooks SC, Lin S, Taher A and Morrison LJ. CPR quality during out-of-hospital cardiac arrest transport. Resuscitation. 2017;114:34-39.

8. International Liaison Committee on R. 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Part 2: Adult basic life support. Resuscitation. 2005;67:187-201.

9. Sayre MR, Koster RW, Botha M, Cave DM, Cudnik MT, Handley AJ, Hatanaka T, Hazinski MF, Jacobs I, Monsieurs K, Morley PT, Nolan JP, Travers AH and Adult Basic Life Support Chapter C. Part 5: Adult basic life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Circulation. 2010;122:S298-324.

10. Sunde K, Wik L and Steen PA. Quality of mechanical, manual standard and active compression-decompression CPR on the arrest site and during transport in a manikin model. Resuscitation. 1997;34:235-42.

11. Thomassen O, Skaiaa SC, Assmuss J, Østerås Ø, Heltne JK, Wik L and Brattebo G. Mountain rescue cardiopulmonary resuscitation: a comparison between manual and mechanical chest compressions during manikin cardio resuscitation. Emerg Med J. 2017;34:573-577.

12. Abrams T and Torfason L. Evaluation of the Quality of Manual, Compression-Only Cardiopulmonary Resuscitation in a Moving Ski Patrol Toboggan. High Alt Med Biol. 2020;21:52-61.

13. Stone CK and Thomas SH. Can correct closed-chest compressions be performed during prehospital transport? Prehospital & Disaster Medicine. 1995;10:121-3.