Article

Resuscitation quality of rotating chest compression providers at one-minute vs. two-minute intervals: A mannequin study

a b s t r a c t

Objective: The aim of this randomized cross-over study was to compare one-minute and two-minute Continuous chest compressions in terms of chest compression only CPR quality metrics on a Mannequin model in the ED. Materials and methods: Thirty-six emergency medicine residents participated in this study. In the 1-minute group, there was no statistically significant difference in the mean compression rate (p = 0.83), mean compres- sion depth (p = 0.61), good compressions (p = 0.31), the percentage of complete release (p = 0.07), adequate compression depth (p = 0.11) or the percentage of good rate (p = 51) over the four-minute time period. Only Flow time was statistically significant among the 1-minute intervals (p b 0.001). In the 2-minute group, the mean compression depth (p = 0.19), good compression (p = 0.92), the percentage of complete release (p = 0.28), adequate compression depth (p = 0.96), and the percentage of good rate (p = 0.09) were not statistically significant over time. In this group, the number of compressions (248 +- 31 vs 253 +- 33, p = 0.01) and mean com- pression rates (123 +- 15 vs 126 +- 17, p = 0.01) and flow time (p = 0.001) were statistically significant along the two-minute intervals. There was no statistically significant difference in the mean number of chest compressions per minute, mean chest compression depth, the percentage of good compressions, complete release, adequate chest compression depth and percentage of good compression between the 1-minute and 2-minute groups.

Conclusion: There was no statistically significant difference in the quality metrics of chest compressions between 1- and 2-minute chest compression only groups.

(C) 2017

Introduction

The quality of Cardio-pulmonary resuscitation may be affected by several factors. Adequate chest compression rate, compression depth and allowing chest recoil and minimizing the interruptions during chest compressions may increase the chance of survival. However, rescuer fa- tigue usually occurs rapidly during chest compressions, thus negatively affecting the chance of survival. Previous studies have shown that rescu- er fatigue that decreases the efficacy of chest compressions may occur within 1 min of CPR [1-3]. Cerebral and coronary perfusion pressures are important determinants of successful resuscitation, so the Quality of chest compressions is important. In a previous study, it was shown that the percentage of adequate compressions decreased from 93% to 39% after 3 min of CPR [1].

Current Basic Life Support (BLS) Guidelines suggest 30 compressions between 2 rescuers breathing with duration of 5 cycles, or 2 min before

* Corresponding author at: Akdeniz University School of Medicine, Department of Emergency Medicine, Antalya, Turkey.

E-mail address: [email protected] (E. Goksu).

shifting to another rescuer and minimizing the elapsed time b 10 s be- tween the compressions [4].

As previous studies have shown, the rapid decay of CPR efficacy within a minute means that more frequent rotation of rescuers may be an appropriate solution for the surrogate end-points for chest com- pression quality [5].

The aim of the present study was to compare one-minute and two- minute continuous chest compression only CPR in terms of CPR quality metrics on a mannequin model in the ED.

Materials and methods

This is a randomized cross-over study. The study was performed in a tertiary care facility ED with an annual census of 90.000 patients. The in- stitutional review board approved the study. Verbal consent was ob- tained from the participants.

Thirty-six emergency medicine residents participated in this study. Demographic properties of the participants (age, gender, BMI) were re- corded. All the providers participated in both the 1-minute and 2-min- ute scenarios. All participants were randomly allocated to work in pairs to start chest compression in one of the aforementioned scenarios.

https://doi.org/10.1016/j.ajem.2017.10.035

0735-6757/(C) 2017

Table 2

Mean age (years) 28 +- 1.6

PGY

Table 1

Demographics of participants.

2.1. Statistical analysis

Gender

The study data were analyzed in SPSS 21.0 for Windows (SPSS Inc.,

Male

25 (69.4%)

Chicago, IL). Demographic and baseline characteristics were summarized

Female

11 (30.6%)

as a mean +- SD for continuous variables and as a percentage of the group

6
  • 7
  • 13
  • 10
  • BMI (kg/m2) 24.9 +- 3.4

    PGY: Postgraduate year, BMI: Body Mass Index.

    for categorical variables. Non-normally distributed data are presented as medians (interquartile range). The normality analysis was performed with the Kolmogorov-Smirnov test. Changes in mean compression rate, mean compression depth, good compression, percentage of recoil, per- centage of appropriate chest compression depth, percentage of good compression rate over four 1-minute blocks were analyzed with repeated measures analysis of variance or Friedman test according the distribution of data. A paired samples t-test was used to compare the measurements at two time points. Comparisons of the groups were performed with either a

    Comparison of quality parameters among the groups.

    2-Minute group

    1-Minute group

    p value

    Numbers of chest compressions/min

    125 +- 16

    125 +- 18

    0,97

    Mean chest compression depth

    46.5 +- 8

    47.9 +- 7.6

    0,45

    The percentage of good compressions

    21.9 +- 30

    28.2 +- 36

    0,75

    The percentage of complete release

    51.6 +- 37

    54.7 +- 41

    0,73

    Adequate compression depth

    39.6 +- 39

    42.9 +- 40

    0,66

    Good rate

    24.3 +- 3.4

    31.9 +- 3.5

    0,38

    Flow time

    99.7 +- 0.3

    99.6 +- 0.5

    0,40

    A floor-based Laerdal Resusci-Anne mannequin (Laerdal Medical, Sta- vanger, Norway) and a CPRmeter (Laerdal Medical, Stavanger, Norway) were used. A CPR meter is a Feedback device that is placed over the ster- num of the victim. The display screen of the device gives visual informa- tion for compression depth, release and rate of chest compressions and with a SD card, the CPR meter stores the data of mean chest compression depth, mean compression rate, total amount of compressions, the per- centage of good compressions, complete release, percentage of adequate chest compression depth, percentage of good compression rate and flow time. CPR targets for the device is a compression depth of N 50 mm with a deep accuracy of +-10% and a compression rate target of 100-120/min +- 3/min. Flow time was defined as compressions that were ongoing, good rate was defined as a rate in the range of 100-120 compressions/min. Ad- equate depth was defined as depth N 50 mm, complete recoil is a release force smaller than 2.5 kg. A good compression was defined as a combina- tion of compressions with adequate depth, complete release and correct rate. Average depth and rate was defined as mean compression rate and depth. Demographic properties of the study participants and mean chest compression depth, mean compression rate, total number of com- pressions, the percentage of good compressions, complete release, per- centage of adequate chest compression depth, percentage of good compression rate and flow time were recorded by CPR meter. For the pur- pose of this study, the display screen of the CPR meter was covered with an adhesive band. Participants were asked to perform chest compression according to the suggestions of the latest Resuscitation guidelines [4].

    In the 1- and 2-minute scenarios, the rescuers rotated every one- minute and 2 min respectively. But chest compressions were interrupted only every 2 min for 10 s to simulate pulse and breathe check.

    Student t-test or Mann-Whitney test according to the distribution of data. A p b 0.05 was accepted as statistically significant.

    Results

    Thirty-six emergency medicine residents participated in this study.

    Demographics of study population are depicted in table 1.

    The mean number of chest compressions per minute in the 1-minute and 2-minute scenarios were 125 +- 18 (95%; CI: 119-131) and 125 +- 59 (95%; CI: 120-131) respectively. The mean chest compression depth in the 1-minute scenario was 47.9 +- 7.6 mm and in the 2-minute scenario it was 46.5 +- 8 mm. The percentage of good compressions were (21.9

    +- 30 vs 28.2 +- 36), the percentage of complete release (51.6 +- 37 vs

    54.7 +- 41), adequate compression depth (39.6 +- 39 vs 42.9 +- 40),

    good rate (24.3 +- 3.4 vs 31.9 +- 3.5) and flow time (99.7 +- 0.3 vs 99.6

    +- 0.5) in the 2-minute and 1-minute groups respectively (Table 2).

    In the 1-minute group, there was no statistically significant differ- ence in mean compression rate (p = 0.83), mean compression depth (p = 0.61), good compressions (p = 0.31), the percentage of complete release (p = 0.07), adequate compression depth (p = 0.11) and the per- centage of good rate (p = 51) over the four-minute time period. In the 1-minute group, flow time was statistically significant among the 1- minute intervals (p b 0.001). In the 2-minute group, mean compression depth (p = 0.19), good compression (p = 0.92), the percentage of com- plete release (p = 0.28), adequate compression depth (p = 0.96), the percentage of good rate (p = 0.09) was not statistically significant over time. In this group, the number of compressions (248 +- 31 vs 253 +- 33, p = 0.01) and mean compression rates (123 +- 15 vs 126

    +- 17, p = 0.01) and flow time (p = 0.001) were statistically significant among the two-minute intervals.

    Over the scenario period, there was no statistically significant differ- ence in the mean number of chest compressions per minute, mean chest compression depth, the percentage of good compressions, complete re- lease, and adequate chest compression depth and percentage of good compression between the 1-minute and 2-minute groups (Table 2).

    In the 1-minute chest compression scenario, mean compression depth, percentage of adequate chest compression depth, percentage of recoil and flow time was statistically significant according to gender (Table 3). In the 2-minute chest compression scenario, only percentage of recoil was statistically significant according to gender (Table 3). In the

    Table 3

    Comparison of quality metrics according to gender.

    Male Female p value (CI)

    minute scenario Mean compression depth (mm) 50.1 +- 6.1 42.8 +- 8.4 0.01

    Adequate chest compression depth (%) 53.4 +- 40.7 18.9 +- 30.4 0.007

    Recoil (%) 45.2 +- 42 76.4 +- 30.3 0.02

    Flow time (%) 99.57 +- 0.6 99.9 +- 0.1 0.02

    minute scenario Mean compression depth (mm) 47.6 +- 8.1 43.9 +- 7.4 0.07

    Adequate chest compression depth (%) 48.1 +- 40.3 20.4 +- 31 0.05

    Recoil (%) 42.6 +- 40.3 72.1 +- 33.6 0.02

    Flow time (%) 99.7 +- 0.3 99.9 +- 0.2 0.2

    Fig. 1. Comparison of mean chest compression rate in 1-minute and 2-minute groups.

    1- and 2-minute scenarios, while adequate compression depth is better in the male participant group, percentage of recoil is better in the female participant group. (See Figs. 1-3.)

    Discussion

    According to the results of this study, there was no statistically sig- nificant difference in the quality metrics of chest compressions between 1- and 2-minute chest compression only groups.

    The American Heart Association and European Cardiovascular Socie- ty 2015 guidelines emphasize the importance of high quality CPR [4,6]. Chest compression rate of at least 100-120 compressions/min, chest compression depth of minimum 5 cm but b 6 cm, the allowing for

    complete recoil and the minimizing of interruptions are important end- points in the performance of high quality CPR.

    In a similar study design Manders et al. compared the number of ef- fective compressions in a Mannequin study. In their study, the mean number of effective chest compressions in the 1-minute scenario was

    573.4 versus 597.6 in the 2-minute scenario (p = 0.70,95%CI492.7- 654.1 and 502-693.2, respectively). This study found no significant dif- ference in the number of effective chest compressions in the 1-minute or 2-minute groups [7].

    In another prospective cross-over study, cardiopulmonary resuscita- tion quality was compared in 1-minute and 2-minute groups. The aver- age rate of compression per minute (121 vs. 124), the percentage of appropriate compression depth (76% vs. 54%), the average depth (53

    Fig. 2. Comparison of mean chest compression depth in 1-minute and 2-minute groups.

    Fig. 3. Comparison of percentage of recoil in 1-minute and 2-minute groups.

    vs.47 mm), and the number of compressions with no error (62 vs.47%) were significantly different among the 1-minute and 2-minute groups [8]. In this study, the mean chest compression rate was 121.0 +- 13.01 and 124.09 +- 11.71 (p = 0.003) in the 1-minute and 2-minute scenar- ios respectively. In our study we had the similar mean compressions rates (125 +- 18 vs 125 +- 16). Although in the previous study, the au- thors found a statistically significant difference in terms of chest com- pression rate, its clinical significance is questionable. In our study population, the average depth of compression was shallow when com- pared with the previous study. In the study of Gianotto-Oliviera et al., the mean compression depth was 53.59 +- 7.48 mm in the 1-minute scenario and 47.7 +- 7.68 mm in the 2-minute scenario. Here, we believe that the percentage of adequate chest compression depth is a more ac- curate parameter in revealing the Quality of CPR. In our study the per- centage of adequate compression depth was significantly lower than in the previous study (42.9 +- 40, 39.6 +- 39 vs. 76.21 +- 35, 54.3 +- 40). Moreover, the findings of Gianotto-Oliviera et al. were not support- ed in other similar studies. In another study, in contrast to the study of Gianotto-Oliviera et al., nearly half of the participants were not able to achieve the average compression depth of >=50 mm in the 2-minute sce- nario [9]. Yet another study showed an inverse relationship between chest compression rate and depth [10]. Gender difference may partially explain this difference, as most of their participants were male (84%) [7]. In our study, the percentage of adequate chest compressions in the 2-minute scenario male participants group was similar to the previ- ous study (Table 3).

    In a study of in-hospital cardiac arrest patients, it was shown that the chest compression rate did not change significantly according to single rescuer performance, with an initial mean rate of 105 +- 11/min and mean rate after 3 min of 106 +- 9/min. There was no significant change in adequate chest compression depth over 90 s but, there was linear de- crease of appropriate chest compression depth after 90 s [5]. In the study of Nishiyama et al., chest compression depth was shown to de- crease more rapidly during chest compression-only CPR than in conven- tional CPR [11]. Although the percentage of good compressions is lower than expected in our study, there was no difference between 1- and 2- minute groups in terms of quality parameters. It seems that increasing the compression rate decreases the percentage of adequate chest com- pression depth, and that this situation is independent whether the

    participant is in the 1- or 2-minute group. The participants of this study included health care professionals, so for lay rescuers, the results of the 1- and 2-minute scenarios may be different, so rotating a lay res- cuer every minute may be an alternative approach for the chest com- pression only CPR group.

    Limitations

    This study has several limitations. Firstly, this is a mannequin study. Although standardization of the parameters is possible with this study design, it may differ from real life experiences. Secondly, we have col- lected the data for 4 min. Longer periods of data collection may give dif- ferent results. Finally, we did not record the time required to change the rescuers in the 1-minute scenario. Although in a previous study inter- ruption time was 2.8 s, we do not know the hemodynamic effects of this delay on humans [7].

    Conclusion

    According to the results of this study there is no difference in the quality metrics of chest compressions between 1- and 2-minute chest compression only groups. Several previous studies revealed that chest compressions with appropriate depth decreased more rapidly during chest compression-only CPR than in conventional CPR. Providers may therefore rotate their roles every minute when performing chest only CPR.

    Conflict of interest

    None.

    References

    1. Hightower D, Thomas SH, Stone CK, Dunn K, March JA. Decay in quality of closed chest compressions over time. Ann Emerg Med 1995;26:300-3.
    2. Perkins GD, Augre C, Rogers H, Allan M, Thickett DR. CPREzy: an evaluation during simulated cardiac arrest on a hospital bed. Resuscitation 2005;64:103-8.
    3. Ochoa FJ, Ramalle-Gomara E, Lisa V, Saralegui I. The effect of rescuer fatigue on the quality of chest compressions. Resuscitation 1998;37:149-52.
    4. Kleinman ME, Brennan EE, Goldberger ZD, Swor RA, Terry M, Bobrow BJ, et al. Part 5: adult basic life support and cardiopulmonary Resuscitation quality: 2015 American

      Heart Association guidelines update for cardiopulmonary resuscitation and emer- gency cardiovascular care. Circulation 2015 Nov 3;132(18 Suppl 2):S414-35.

      Sugerman Noah T, Herzberg Daniel, Leary Marion, Weidman Elizabeth K, Edelson Dana P, Vanden Hoek Terry L, et al. Rescuer fatigue during actual in-hospital cardio- pulmonary resuscitation with audiovisual feedback: a prospective multicenter study. Resuscitation 2009 Sep;80(9):981-4.

    5. Perkins GD, Handley AJ, Koster RW, Castren M, Smyth MA, Olasveengen T, et al. Eu- ropean resuscitation council guidelines for resuscitation 2015: section 2. Adult basic life support and Automated external defibrillation. Resuscitation 2015 Oct;95:81-99.
    6. Manders S, Geijsel FE. Alternating providers during continuous chest compressions for cardiac arrest: every minute or every two minutes? Resuscitation 2009 Sep; 80(9):1015-8.
    7. Gianotto-Oliveira R, Gianotto-Oliveira G, Gonzalez MM, Quilici AP, Andrade FP, Vianna CB, et al. Quality of continuous chest compressions performed for one or two minutes. Clinics (Sao Paulo) 2015 Mar;70(3):190-5.
    8. Sanchez B, Algarte R, Piacentini E, Trenado J, Romay E, Cerda M, et al. Low compli- ance with the 2 minutes of uninterrupted chest compressions recommended in the 2010 international resuscitation guidelines. J Crit Care 2015 Aug;30(4):711-4.
    9. Field RA, Soar J, Davies RP, Akhtar N, Perkins GD. The impact of chest compression rates on quality of chest compressions – a manikin study. Resuscitation 2012 Mar; 83(3):360-4.
    10. Nishiyama C, Iwami T, Kawamura T, Ando M, Yonemoto N, Hiraide A, et al. Quality of chest compressions during continuous CPR; comparison between chest compres- sion-only CPR and conventional CPR. Resuscitation 2010 Sep;81(9):1152-5.

    Leave a Reply

    Your email address will not be published. Required fields are marked *