Optimal chest compression technique for paediatric cardiac arrest victims

Paediatric OHCA is generally considered to have a poor prognosis, and resuscitative
efforts for paediatric arrest victims have often been assumed to be futile 4]. However, recent studies have reported that outcomes of children are better than
those of adults after OHCA 1],12], and the importance of performing high-quality chest compressions during paediatric
CPR has been emphasised 13]. Only a few reports have heretofore compared the quality of chest compressions using
two-hand and one-hand techniques 7]-9], and no study has compared the qualities of right and left one-hand chest compressions.

In general, the younger and smaller the child, the faster their normal heart rate.
Previous studies reported similar compression rates for one-hand and two-hand techniques
7],9], but compression rates fell faster with a one-hand technique 7]. However, a recent study reported that the number of chest compressions per 30-second
epoch did not decline over a 2-minute study period during simulated paediatric CPR
performed by highly trained personnel with CPR experience 14]. Unfortunately, the authors did not describe the compression technique. Our study
showed no differences in compression rate among the three techniques, which remained
within the recommended range of ?100 compressions/min throughout the 2-minute test
period, and no change in the compression rate over time for any technique. This indicates
that all three techniques allow inexperienced rescuers to not only achieve the recommended
compression rate but also maintain this rate for 2 minutes of continuous compressions.

Our study demonstrated that the compression depth using the two-hand technique was
greater than that of the left or right one-hand technique. These results are consistent
with those of two previous simulated paediatric resuscitation studies. Stevenson et
al. reported that two-hand chest compressions produced significantly higher mean and
peak pressures than one-hand compressions 8]. Udassi et al. likewise showed a trend towards higher compression depth and peak
compression pressure with the two-hand technique, although the difference between
two-hand and one-hand techniques was not statistically significant 9]. In this study, the depth difference between one-hand and two-hand techniques was
2.4–3.3 mm. As there is no study that has identified the correlation of compression
depth with treatment outcome in paediatric victims, it is difficult to determine the
clinical significance of our result. For adult victims, Vadeboncoeur et al. reported
that each 5-mm increase in mean chest compression depth significantly increased both
survival in general and survival with favorable functional outcome, with an odds ratio
of 1.29 and 1.30, respectively 15]. Our study also showed that compression depth continued to decline over time during
the 2-minute trial period, although the decline was most prominent between the first
and second epoch. The pattern of compression depth decay over time was comparable
for all techniques, thereby suggesting that rescuer fatigue affected all techniques
similarly. Udassi et al. reported no significant differences between two-hand and
one-hand techniques for compression depth or peak compression pressure over time during
simulated 5-minute paediatric CPR 9]. One possible explanation for the difference between their results and ours is that
unlike the previous research, our participants were inexperienced rescuers who were
not as capable of detecting deterioration in their technique due to lack of experience,
and so may not attempt to compensate as much. With the manikin used in our study,
a compression depth of 46.7 mm (one third the AP diameter) should be achieved to meet
the current guidelines. However, we did note that almost all participants failed to
achieve the recommended chest compression depth during every technique. Although our
inexperienced participants may not be capable of compressing to a sufficient depth,
other studies also showed that well-trained health care practitioners could not achieve
the recommended depth in child manikins 9],14],16],17]. This implies that child manikins may differ from real children in resistance and
stiffness of the chest wall.

Complete chest recoil is another important aspect of high-quality CPR 18]-20]; however, the influence of compression method on residual leaning rate has not been
investigated. In this study, the residual leaning rate was higher with the two-hand
technique than the left or right one-hand techniques. The posture of the two-hand
technique with both arms forming an isosceles triangle will aid rescuers in loading
their weight on the chest wall comfortably during each compression. Although this
posture is helpful to achieve deeper compression, the risk of incomplete recoil would
be increased. Interestingly, participant height was also associated with the residual
leaning rate, and there was also a tendency for height to correlate inversely with
the amount of recoil allowed. This result is consistent with that of a previous study
in which the authors reported that rescuers 170 cm in height exhibited significantly
more residual leaning than rescuers 170 cm 21].

We used the Q-CPR™ compression sensor on the manikin’s chest for recording chest compression
quality parameters, and the hand position of the participants was predetermined on
the sensor. Therefore, we could not determine whether the techniques differed in their
ability to maintain the correct position of the hand(s). Instead of directly evaluating
correct hand position, we recorded the number of times the hand slipped on the sensor.
In Peska’s study, 65.6% of participants preferred the two-hand compression technique,
partly because it was easier to maintain their balance with that technique 7]. However, our results did not demonstrate a difference among techniques for the number
of times the hand(s) slipped. Our participants did think that performing chest compressions
using the two-hand technique was easier than the other techniques. Unfamiliarity with
the one-hand technique might have contributed to its subjective difficulty. Also,
for such a reason as mentioned, the majority of participants favoured the two-hand
compression technique both before and after the experimental session, which was consistent
with the findings of previous studies 7],8].

Handedness is the tendency to consistently favour the use of one hand/arm for performing
selected tasks. In general, dominant arm performance is better for activities requiring
precision of inter-joint coordination (e.g., cutting paper with scissors), whereas
non-dominant arm performance is more specialized for control of steady-state limb
position (e.g., holding a piece of paper for cutting) 22]-24]. Contrary to our expectations, chest compression quality was similar for the right
and left one-hand techniques. This suggests that arm dominance does not affect compression
depth and rate. Sainburg and Kalakanis reported that during rapid targeted reaching
movements, the right and left hands showed a similar time course of improvement in
final position accuracy over repeated trials, and the final accuracy was similar for
both hands after task adaptation 25]. These findings are consistent with our results. Indeed, performance of chest compressions
may be affected by multiple factors, such as age, gender, and muscle power of the
rescuer, in addition to handedness.

There were limitations to this study. First, the study used a child manikin to simulate
paediatric cardiac arrest. Although various child manikins are widely used in paediatric
CPR training and studies investigating CPR performance, they may not exactly replicate
the characteristics (e.g., stiffness, resistance) of the paediatric thorax. Therefore,
our findings may not be applicable to actual clinical settings. Additionally, our
use of only a 6-year-old child manikin indicates that our results may not reflect
chest compression performance on children of all ages. Second, our use of the Q-CPR^TM compression sensor to record chest compression quality parameters may have affected
the results, as the participants were not familiar with performing compressions on
it. However, we attempted to minimise this confounding factor by allowing a practice
session before starting the experimental session. Third, most participants were right-handed
(as are most Koreans), so we were unable to examine the effect of handedness on chest
compression quality. The participants were also young and healthy; thus, our results
may not be generalisable to other rescuers. However, most parents are also young and
healthy, and the benefits of a two-hand technique may be better suited for older and
less healthy individuals who may have more difficulty providing the compression force
required for the one-hand technique. Fourth, although the medical students who participated
in the study were inexperienced in real-world CPR, they would have had more knowledge
of resuscitation, anatomy, and physiology than a normal population. Additionally,
our participants were more likely to be enthusiastic and confident, considering that
they all actively responded to posters advertising the study. These characteristics
of our participants hinder generalization of our results to inexperienced rescuers.
Fifth, participants were aware that they were being evaluated and videotaped. This
may have led to the Hawthorne effect, in which the participants performed better than
they would in a real-life situation. Conversely, they may have performed compressions
less effectively because no actual child required resuscitation. Nevertheless, except
for the issue of the participants’ handedness, it is likely that these limitations
would have affected chest compression performance similarly for all techniques. Finally,
we did not include ventilation despite the fact that ventilation is more important
in asphyxia-induced arrest (the most common etiology in paediatric victims). We do
acknowledge that this was a simulation study limited to the investigation of compression
and suggest that further studies are needed to explore these limitations in a clinical
context.

In this study of simulated paediatric CPR performed by inexperienced rescuers, we
demonstrated that the mean compression rate did not differ among three chest compression
techniques, nor did the compression rate change over a 2-minute period of continuous
chest compressions for any technique. The mean compression depth using the two-hand
technique was greater than that of the left or right one-hand technique, but most
participants did not achieve the recommended depth with any technique. Moreover, the
chest compression depth declined over time during all three techniques. The incomplete
chest recoil occurred more frequently with the two-hand technique than with the one-hand
technique. The performance of chest compressions was similar for the right and left
one-hand techniques. These findings are important for instructors as well as for team
members who watch CPR quality during actual resuscitation. By knowing tendencies of
different techniques, they can use this information to recognise these specific problems
with performance.