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Comparison of overlapping (OP) and adjacent thumb positions (AP) for cardiac compressions using the encircling method in infants
  1. Jung Soo Lim1,
  2. YongCheol Cho1,
  3. Seung Ryu1,
  4. Jin Woong Lee1,
  5. SeungWhan Kim1,
  6. In-Sool Yoo1,
  7. YeonHo You1,
  8. Byung Kook Lee2,
  9. Jin Hong Min3,
  10. Won Joon Jeong4
  1. 1Department of Emergency Medicine, College of Medicine, Chungnam National University, Daejeon, South Korea
  2. 2Chonnam National University Hospital, Gwangju, South Korea
  3. 3Chungbuk National University, Cheongju, South Korea
  4. 4Konyang University, Daejeon, South Korea
  1. Correspondence to Dr YeonHo You, Department of Emergency Medicine, College of Medicine, Chungnam National University Hospital, 640 Daesa-dong, Jung-gu Metropolitan City, Daejon 301-721, South Korea; yyo1003{at}naver.com

Footnotes

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval This study was conducted with the approval of the Regional Ethics committee at Chungnam national university hospital Institution, South Korea.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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Introduction

Infant cardiopulmonary resuscitation (CPR) is usually associated with poor outcomes, such as high morbidity and mortality rates. Overall survival to discharge was 12%, and intact neurological survival occurred in only 4% of patients. The survival rates after inhospital paediatric cardiac arrest are substantially better, with 27% of children surviving to hospital discharge, 65% of whom had favourable neurological outcomes.1 ,2 In addition, the rate of survival without major neurological deficit is higher with prompt chest compression.3 ,4 Besides prompt chest compression, the following are the keystones to obtaining favourable outcomes in infant chest compression: optimal site, rate and depth. To generate the maximal cardiac output by chest compression, the ventricle should be compressed.5–8

A study described the infant ventricle to be located underneath one-fourth of the sternum. Therefore, the liver and the lungs could be compressed during infant CPR if rescuers apply adjacent thumb position (AP), which involves one-fourth of the sternum. For this reason, we propose overlapping thumb position (OP) as an alternative technique, with the aim of providing compression to the ventricle without compressing the liver or the lungs.9–13

We hypothesised that OP would produce higher mean arterial pressure (MAP) during chest compression in the infant model and that it would cause less rescuer fatigue over time than AP.

Methods

Volunteers who participated in an 8-h training in infant CPR by OP conducted from December 2010 to August 2011 were enrolled in the study. All volunteers were students in the emergency medical technician course. Volunteers who were pregnant and had arthritis were excluded from the study. We obtained the basic data of the volunteers including sex, age, height and body weight and separated the volunteers into two groups to conduct this study as a crossover design. The volunteers in group 1 initially practised OP and then shifted to AP after taking a 2-week break. On the other hand, those in group 2 initially practised AP and then shifted to OP after taking a 2-week break. The volunteers practised OP with the thumb of their dominant hand as the lower thumb of the two during the first minute and then alternately every minute with the other thumb. We measured the heart rate, the respiratory rate and the end-tidal CO2 of volunteers before the chest compression as the baseline data, and we monitored the same every minute during a 5-min chest compression. We measured the changes in heart rate, respiratory rate and end-tidal CO2 from the baseline data. We asked the volunteers at what time they felt exhausted and evaluated their fatigue level every minute during a 5-min chest compression by using the Likert scale (1=no fatigue to 5=extreme fatigue). We embedded a 50-ml saline bag in the chest of the Resusci Baby Basic and Skill Guide manikins (Laerdal Medical, Stavanger, Norway) (figure 1) and inserted a 16-gauge needle into the bag, which is connected to an Accutrans disposable blood pressure transducer (Biosensors International, Kallang, Singapore) and Solar 8000M patient monitor (GE Medical Systems, Milwaukee, Wisconsin, USA). We measured the simulated systolic blood pressure (SBP), the simulated diastolic blood pressure, the simulated pulse pressure (PP) and MAP generated during a 5-min chest compression.14–17

Figure 1

Images showing (A) the 50-ml saline bag embedded in the chest of the infant manikin, (B) chest compression using overlapping thumb position and (C) chest compression using adjacent thumb position.

We analysed the data from each technique using the Kolmogorov–Smirnov test, χ2 test, Fisher's exact test, paired t test and Wilcoxon test. The data were considered statistically significant if p<0.05.

Results

Comparison between the chest compression effects by OP using the thumb of the dominant hand and that of the non-dominant hand

Of the 48 volunteers enrolled in the study, 30 (62.5%) were men. The mean height was 169.63±7.67 cm, and the mean body weight was 63.19±13.05 kg. The chest compression rates generated using the thumb of the dominant hand and that of the non-dominant hand were, respectively, 108.91±10.73 and 107.09±9.67 bpm at the first minute (p=0.15), 107.88±10.13 and 109.42±10.52 bpm at the second minute (p=0.17), 108.93±11.87 and 109.27±11.27 bpm at the third minute (p=0.62), 108.62±10.86 and 109.61±10.87 bpm at the fourth minute (p=0.18) and 108.59±10.41 and 110.65±12.12 bpm at the fifth minute (p=0.05). There were no significant differences between the thumb of the dominant hand and that of the non-dominant hand (table 1).

Table 1

Comparison between the pressures generated by chest compression using the thumb of the dominant hand (D) and that of the non-dominant hand (N)

Comparison between the chest compression effects using OP and AP

The grip strengths by OP and AP were 24.71±6.80 and 21.80±5.45 mm Hg (p<0.01), respectively. The chest compression rates by OP and AP were, respectively, 107.74±9.80 and 105.56±11.82 bpm at the first minute (p=0.25), 108.41±9.64 and 101.84±20.66 bpm at the second minute (p=0.06), 108.86±11.26 and 106.12±13.83 bpm at the third minute (p=0.13), 108.66±10.31 and 107.31±13.18 bpm at the fourth minute (p=0.45) and 109.29±10.12 and 107.97±13.03 bpm at the fifth minute (p=0.42).

Significant differences were observed between OP and AP in SBP, MAP and PP (table 2).

Table 2

Comparison between the pressures generated by chest compression using the superimposed-thumb and alongside-thumb techniques

Comparison between the rescuer fatigue levels when using OP and AP

The volunteers felt tired after 3.14±0.42 min using OP and after 2.72±0.54 min using AP (p=0.29). Although the change of heart rate was higher in AP than in OP during a 5-min chest compression, there were no significant differences. There were significant differences between the Likert scale at the second, third, and fifth minutes of chest compression by OP and AP (table 3).

Table 3

Comparison between the rescuer fatigue levels when using the superimposed-thumb and alongside-thumb techniques

Discussion

Thaler and Stobie18 reported that in using OP, rescuers stand at the head end of the infant and apply chest compression using the 2-thumb encircling-hand technique, pushing the liver into the abdomen. AP has been considered one of the foundations of the modifications of the 2-thumb encircling-hand technique. A rescuer must compress the ventricle, located underneath one-fourth of the sternum, by chest compression to generate the maximal cardiac output.5–8 In previous studies that compared the two thumbs with two fingers technique, European Resuscitation Council states that the most effective technique for providing chest compressions is to place the two thumbs side by side over the lower third of the sternum just below an imaginary line joining the nipples, with the fingers encircling the torso and supporting the back, while the North American guidelines are unclear.19 ,20

In this study, OP generated higher SBP, MAP and PP than AP as the difference of the grip strengths. However, there were no statistically significant differences between the two techniques in simulated diastolic blood pressure because diastolic pressure is dependent on the elasticity of the manikin. Rescuer fatigue, which was measured with the Likert scale, was more severe when using AP than when using OP.

There are several limitations to this study. First, the study was conducted using infant manikins. Second, the volunteers were not blinded to the techniques they were performing. Third, we chose not to perform ventilations during this study. Finally, this study enrolled only 48 volunteers who were trained in infant CPR.

Conclusion

Based on the results of the study, we conclude that higher intrathoracic pressures were achieved by OP. However, further studies are needed to validate these effects of overlapping thumbs technique in infant CPR, not manikin.

References

View Abstract

Footnotes

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval This study was conducted with the approval of the Regional Ethics committee at Chungnam national university hospital Institution, South Korea.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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