Comparison of two chest compression techniques during infant resuscitation. A randomized, cross-over study

Abstract

Introduction. High quality chest compressions are an inherent element of cardiopulmo-nary resuscitation that directly influences its effectiveness and thus the return of spontaneous circulation. The guidelines of the American Society of Cardiology recommend conducting resuscitation of newborns and infants with one of two techniques: two-finger technique (TFT) or two thumbs technique (TTHT) in which two thumbs are placed on the sternum and the other fingers cover the chest supporting the child's back. However, as numerous studies indicate, each of these techniques has its own advantages and disadvantages.
Aim. The aim of the study was to assess the quality of selected chest compression techniques during simulated cardiopulmonary resuscitation of an infant conducted by final-year medical students.
Material and methods. The consent of the Institutional Review Board of the International Institute of Rescue Research and Education, as well as written consent from all the parents were obtained. The study was designed as a randomized, cross-over study. The study was attended by 41 students in their final year of medicine. Participants of the study performed a two-minute cycle of cardiopulmonary resuscitation on an infant based on a schedule of 15 chest compressions: 2 rescue breaths. Chest compressions were carried out by two techniques: TTHT and the innovative technique of two thumbs (NTTHT). Only the parameters concerning the quality of chest compressions were analyzed in the study.
Results. Chest compressions based on NTTHT compared with TTHT were associated with a higher percentage of chest compressions performed at the appropriate depth (94% (IQR: 87-96) vs. 92% (IQR: 88-95); p = 0.003), better chest relaxation (94% (IQR: 92-99) vs. 13% (IQR: 9-18); p < 0.001), more correct positioning of the hands on the chest (98% (IQR: 98-100) vs. 95% (IQR: 89-97); p = 0.045) and less time without chest compressions (4.5 s (IQR: 3-5) vs. 5.5 s (IQR: 4-6); p = 0.038). Depth of chest compressions using TTHT was 42 mm (IQR: 39-44) and 41 mm (IQR: 39-42) for NTTHT.
Conclusions. In the conducted simulation study, students in their final year of medicine using an innovative method of chest compressions were associated with higher-quality compressions of the infant's chest compared to the recommendations by the American Society of Cardiology or the European Resuscitation Council.

Full text

DOI: https://doi.org/10.25121/PNM.2018.31.4.211 Post N Med 2018; XXXI(4): 211-216
211
©Borgis
Jacek Smereka1, *Lukasz Szarpak2, Elzbieta Makomaska-Szaroszyk2, Antonio Rodriguez-Nunez3,
Sandra Pyda4, Izabela Sztybor2, Klaudia Wlodarska2, Klaudia Kulak2, Karol Bielski2, Kurt Ruetzler5
Comparison of two chest compression techniques during infant
resuscitation. A randomized, cross-over study
Porównanie dwóch technik uciskania klatki piersiowej podczas resuscytacji
niemowlęcia. Badanie randomizowane krzyżowe
1Department of Emergency Medical Service, Wroclaw Medical University, Poland
2Lazarski University, Warsaw, Poland
3Paediatric Emergency and Critical Care Division, Clinical University Hospital, University of Santiago de Compostela,
Santiago de Compostela, Institute of Research of Santiago (IDIS) and SAMID Network, Spain
4Polish Society of Disaster Medicine, Warsaw, Poland
5Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, USA;
Department of General Anesthesiology, Anesthesiology Institute, Cleveland Clinic, Cleveland, USA
Summary
Introduction. High quality chest compressions are an inherent element of cardiopulmo-
nary resuscitation that directly influences its effectiveness and thus the return of spontaneous
circulation. The guidelines of the American Society of Cardiology recommend conducting
resuscitation of newborns and infants with one of two techniques: two-finger technique (TFT)
or two thumbs technique (TTHT) in which two thumbs are placed on the sternum and the
other fingers cover the chest supporting the child’s back. However, as numerous studies
indicate, each of these techniques has its own advantages and disadvantages.
Aim. The aim of the study was to assess the quality of selected chest compression
techniques during simulated cardiopulmonary resuscitation of an infant conducted by
final-year medical students.
Material and methods. The consent of the Institutional Review Board of the International
Institute of Rescue Research and Education, as well as written consent from all the parents
were obtained. The study was designed as a randomized, cross-over study. The study was
attended by 41 students in their final year of medicine. Participants of the study performed
a two-minute cycle of cardiopulmonary resuscitation on an infant based on a schedule of
15 chest compressions: 2 rescue breaths. Chest compressions were carried out by two
techniques: TTHT and the innovative technique of two thumbs (NTTHT). Only the param-
eters concerning the quality of chest compressions were analyzed in the study.
Results. Chest compressions based on NTTHT compared with TTHT were associ-
ated with a higher percentage of chest compressions performed at the appropriate depth
(94% (IQR: 87-96) vs. 92% (IQR: 88-95); p = 0.003), better chest relaxation (94% (IQR:
92-99) vs. 13% (IQR: 9-18); p < 0.001), more correct positioning of the hands on the chest
(98% (IQR: 98-100) vs. 95% (IQR: 89-97); p = 0.045) and less time without chest compres-
sions (4.5 s (IQR: 3-5) vs. 5.5 s (IQR: 4-6); p = 0.038). Depth of chest compressions using
TTHT was 42 mm (IQR: 39-44) and 41 mm (IQR: 39-42) for NTTHT.
Conclusions. In the conducted simulation study, students in their final year of medicine
using an innovative method of chest compressions were associated with higher-quality
compressions of the infant’s chest compared to the recommendations by the American
Society of Cardiology or the European Resuscitation Council.
Streszczenie
Wstęp. Wysokiej jakości uciski klatki piersiowej stanowią nieodłączny element resuscytacji
krążeniowo-oddechowej wpływający bezpośrednio na jej skuteczność, a tym samym powrót
spontanicznego krążenia. Wytyczne Amerykańskiego Towarzystwa Kardiologicznego zalecają
prowadzenie resuscytacji noworodków i niemowląt jedną z dwóch technik: techniką dwóch
palców (TFT) bądź techniką dwóch kciuków (TTHT), w której dwa kciuki oparte są o mostek,
zaś pozostałe palce obejmują klatkę piersiową, stanowiąc podporę dla pleców dziecka. Jed-
nakże jak wskazują liczne badania, każda z tych technik ma zarówno plusy, jak i minusy.
Konflikt interesów
Conflict of interest
Brak konfliktu interesów
None
Address/adres:
*Lukasz Szarpak
Lazarski University
43 Swieradowska Str., 02-662 Warsaw,
Poland
Phone: +48 500186225
E-mail: lukasz.szarpak@gmail.com
Keywords
chest compressions, cardiopulmonary
resuscitation, baby, medical simulation,
quality
Słowa kluczowe
uciski klatki piersiowe, resuscytacja
krążeniowo-oddechowa, niemowlę,
symulacja medyczna, jakość

212
Jacek Smereka et al.
INTRODUCTION
Sudden cardiac arrest in pediatric patients, including
infants and newborns, occurs relatively less frequently
than in adults (1, 2). Also, the main cause of cardiac
arrest in children is different than in adults (3). In the
case of adults, the main cause of cardiac arrest is car-
diovascular dysfunction, while in the case of pediatric
patients, airway obstruction and progressive hypoxia
result in cardiac arrest (4).
Guidelines for cardiopulmonary resuscitation recom-
mended by the European Resuscitation Council (ERC) as
well as the American Heart Association (AHA) recommend
two techniques for chest compressions for infants and
newborns (5-8). In the case where resuscitation is carried
out by one rescuer, the recommended chest compression
method is the two-finger technique (TFT), during which
chest compressions are performed using two fingers of
one hand at right angles to the chest. In the case when
resuscitation is carried out by two rescuers, the recom-
mended technique is based on two thumbs (TTHT), dur-
ing which the thumbs are located on the patient’s bridge,
and the other fingers, including the chest scaffold, con-
stitute a kind of support for the patient’s back. Both tech-
niques have their pros and cons. In the TFT technique,
studies indicate much better chest relaxation than in the
case of TTHT, however TFT is characterized by chest
compressions at a more shallow depth.
Considering the above assumption, it is important to look
for new techniques of chest compressions, which will be as-
sociated with a higher compression technique. One such
technique is a technique developed by the team of Smer-
eka et al. (9, 10) during which chest compressions are per-
formed using two thumbs set perpendicular to the chest, so
that they constitute a kind of extension of the forearms.
AIM
The aim of the study was to evaluate the chest com-
pression technique prescribed by the guidelines us-
ing the two-thumb method and the author’s two-thumb
method during simulated cardiopulmonary resuscitation
of an infant conducted by final year medical students.
MATERIAL AND METHODS
The consent of the Institutional Review Board of the In-
ternational Institute of Rescue Research and Education,
as well as written consent from all the parents were ob-
tained. The study is a continuation of the authors’ research
cycle on the evaluation of the author’s method of chest
compressions in newborns and infants (9-14). Students
in their final year of medicine who qualified for the study
successfully completed the training module in the field of
emergency medicine. The inclusion criterion in the study
was the 6th year of medical studies student status and the
voluntary willingness to participate in the study. Exclusion
criterion from the study was failure to meet the inclusion
criteria, back pain or pain in the upper limb that prevents
chest compressions. Prior to the study, all participants ex-
pressed their willingness to participate in the study.
Prior to the study, all participants took part in training
in the field of cardiopulmonary resuscitation including
demonstrations in the field of standard chest compres-
sions in infants − TTHT, as well as demonstrations in
the field of chest compressions developed by Smer-
eka et al. (9, 10), during which the thumbs are directed
perpendicular to the chest, constituting a specific pro-
longation of the forearms (fig. 1a, b). Then they had
the opportunity to practice the tested techniques us-
ing an infant simulator. To this end, SimBaby™ was
used (Laerdal, Stavanger, Norway).
The final study was performed the next day after the
demonstrations. During the test, the baby simulator
was placed on the floor in a well-lit room. Participants
of the study were tasked with performing a two-min-
ute cycle of CPR based on the standard of 15 chest
compressions and 2 rescue breaths based on three
tested techniques of chest compressions. Both the
Cel pracy. Celem pracy była ocena jakości wybranych technik uciskania klatki piersio-
wej podczas symulowanej resuscytacji krążeniowo-oddechowej niemowlęcia prowadzo-
nej przez studentów ostatniego roku medycyny.
Materiał i metody. Badanie zostało zaprojektowane jako randomizowane krzyżowe.
W badaniu udział wzięło 41 studentów ostatniego roku medycyny. Uczestnicy bada-
nia wykonywali 2-min cykl resuscytacji krążeniowo-oddechowej niemowlęcia w oparciu
o schemat 15 uciśnięć klatki piersiowej: 2 oddechy ratownicze. Uciśnięcia klatki piersio-
wej były prowadzone dwiema technikami: TTHT oraz nowatorską techniką dwóch kciu-
ków (NTTHT). Analizie poddano jedynie parametry dotyczące jakości uciśnięć klatki pier-
siowej.
Wyniki. Prowadzenie uciśnięć klatki piersiowej w oparciu o NTTHT w porównaniu
z TTHT wiązało się z wyższym odsetkiem uciśnięć klatki piersiowej wykonanych na odpo-
wiednią głębokość (94% (IQR: 87-96) vs. 92% (IQR: 88-95); p = 0,003), lepszą relaksacją
klatki piersiowej (94% (IQR: 92-99) vs. 13% (IQR: 9-18); p < 0,001), bardziej poprawnym
ułożeniem rąk na klatce piersiowej (98% (IQR: 98-100) vs. 95% (IQR: 89-97); p = 0,045)
oraz niższym czasem bez uciśnięć klatki piersiowej (4,5 s (IQR: 3-5) vs. 5,5 s (IQR: 4-6);
p = 0,038). Głębokość uciśnięć klatki piersiowej z wykorzystaniem TTHT wynosiła 42 mm
(IQR: 39-44), zaś w przypadku NTTHT – 41 mm (IQR: 39-42).
Wnioski. W przeprowadzonym badaniu symulacyjnym stosowanie nowatorskiej meto-
dy uciskania klatki piersiowej wiązało się z wyższej jakości uciśnięciami klatki piersiowej
niemowlęcia w porównaniu z rekomendowaną przez wytyczne Amerykańskiego Towarzy-
stwa Kardiologicznego czy też Europejskiej Rady Resuscytacji.

Comparison of two chest compression techniques during infant resuscitation. A randomized, cross-over study
213
order of study participants and methods of chest
compressions were randomized. For this purpose, the
Research Randomizer program was used, with which
participants were divided into three groups. The first
group began resuscitation based on the TTHT tech-
nique and the second group used the NTTHT method.
After, the participants had a 10-minute break and then
chest compressions were performed using a differ-
ent technique. A detailed randomization procedure is
shown on figure 2.
All parameters measured in the study were ana-
lyzed thanks to the software attached to the simulator.
The main parameter measured in the study was the
depth of chest compressions, which in the case of new-
borns should be around 40 mm (7). The derivative of
the depth of chest compressions was the percentage of
chest compressions at the appropriate depth. Additional
parameters related to the quality of chest compressions
were number of compressions fully released, compres-
sion rate, number of compressions with correct hand
positioning and no flow time. No flow time was defined
as the time during which the chest was not squeezed or
rescue breaths were not performed.
All statistical analysis were performed using the
STATISTICA 13.3EN statistical package (StatSoft,
Tulusa, OK, USA). The results were presented as
numbers and percentages or medians and inter-
quartile ranges (IQR). Normal distribution was con-
firmed by the Kolmogorov-Smirnov test. When the
data did not follow normal distribution, non-para-
metric tests were used. The results were considered
significant at p < 0.05.
Fig. 1a, b. Chest compression techniques used in the study: a) standard
two thumb technique (TTHT); b) novel two thumb technique (NTTHT)
Fig. 2. Consolidated standards of reporting trials flow chart diagram

214
Jacek Smereka et al.
RESULTS
The study was attended by 41 students in their final
year of medicine.
The depth of chest compressions using TTHT was
42 mm (IQR: 39-44), while in the case of NTTHT it was
41 mm (IQR: 39-42) (fig. 3a, tab. 1). The number of
compressions with correct depth using distinct com-
pression techniques varied and amounted to 92% (IQR:
88-95) for TTHT, and 94% (IQR: 87-96). The above dif-
ference was statistically significant (p = 0.003) (fig. 3b).
The number of chest compressions fully released for
TTHT technique was 13% (IQR: 9-18), and 94% (IQR:
92-99, p < 0.001) (fig. 3c).
Tab. 1. Results of chest compressions
Parameter
Standard
two thumbs
technique
Novel two
thumbs
technique
p value
Compression depth
(mm)
42
(IQR: 39-44)
41
(IQR: 39-42) 0.127
Number
of compressions with
correct depth (%)
92
(IQR: 88-95)
94
(IQR: 87-96) 0.003
Number
of compressions fully
released (%)
13 (IQR: 9-18) 94
(IQR: 92-99) < 0.001
Compressions rate
(/min)
128
(IQR: 118-130)
122
(IQR: 112-124) 0.054
Number
of compressions
with correct hand
positioning (%)
95
(IQR: 89-97)
98
(IQR: 98-100) 0.045
No flow time (s) 5.5 (IQR: 4-6) 4.5 (IQR: 3-5) 0.038
The frequency of chest compressions based on
thorax compression testing methods is shown on
figure 3d. The compression rate using TTHT was
128 CPM (IQR: 118-130) and 122 CMP (IQR: 112-124)
for NTTHT (p = 0.054).
Number of compressions with correct hand posi-
tioning using TTHT and NTTHT varied and amounted
to 95% (IQR: 89-97) and 98% (IQR: 98-100), respec-
tively (fig. 3e).
No flow time in the case of TTHT was 5.5 s (IQR: 4-6)
and was statistically significantly longer than in the case
of NTTHT resulting in 4.5 s (IQR: 3-5, p = 0.038) (fig. 3f).
DISCUSSION
The study demonstrated the superiority of the NTTHT
technique over the standard two-thumb technique rec-
ommended by the American Heart Association resus-
citation guidelines (7, 8), as well as the European Re-
suscitation Council (5, 6).
The quality of chest compression for both adults
and children depends on many factors, including
depth of compressions, the frequency of compres-
sions, degree of relaxation of the chest, no flow time,
as well as correct hand placement on the chest dur-
ing chest compressions (15). In the Pellegrino et
al. (16), the participants performed chest compres-
sions using two TFT and TTHT techniques over a pe-
riod of eight minutes. In the present study, thanks
to the TTHT technique, a greater depth of compres-
sions of the infant’s chest was obtained than in the
case of the TFT technique. In addition, 64% of the
participants preferred the technique of two thumbs
rather than the two fingers technique. Also, research
carried out by Christman et al. (17) on the neona-
tological model indicate the superiority of the TTHT
technique over the TFT technique. However, as
Christman points out, the depth of chest compres-
sions in the case of uninterrupted chest compres-
sions was 22.1 ± 4.6 mm for TFT and 27.2 ± 5.7 mm
for TTHT (p = 0.0008). For the 3:1 resuscitation
technique, the depth of compressions was 23.7 ±
5.8 and 29 ± 5.4 mm (TFT vs. TTHT, respectively).
The results obtained by Christman indicate an insuf-
ficient depth of chest compressions. Similar results
in case of the TFT technique were also obtained by
other authors (9-14). In turn, in the study, the author’s
method of chest compression where the thumbs are
perpendicular to the chest obtained a similar depth
of chest compressions as in the standard TTHT tech-
nique, however, the percentage of compressions
performed at the appropriate depth recommended
by the AHA guidelines for NTTHT was 94% and was
statistically significantly higher than in the case of
TTHT resulting in 92%. Smereka et al. published
in the journal Frontiers in Pediatrics (12) analyzing
the quality of chest compressions using three tech-
niques; TFT, TTHT, and NTTHT showed that effective
chest compression with the NTTHT was higher than
for TTHT or TFT. This dependence is also confirmed
by other studies (18-20).
Another important parameter from the point of
view of the quality of chest compressions is the lev-
el of chest relaxation. Lee et al. (21) indicated that
the number of high-quality CPR compressions was
the highest at a compression rate of 120 min and in-
creased incomplete recoil occurred with increasing
compression rate. In turn Yannopoulos et al. (22)
indicated that incomplete chest wall recoil during
the decompression phase of CPR increases endo-
tracheal pressure, impedes venous return and de-
creases mean arterial pressure, and coronary and
cerebral perfusion pressures.
In our own studies, using the standard two-thumb
technique (TTHT), the lowest degree of full chest decom-
pression was achieved due to limitations in the abduc-
tion of the thumbs. When using the innovative method
of chest compressions using the NTTHT technique, cor-
rect compression and relieving of chest compressions
by withdrawal of the arms results in full chest relaxation,
thus optimizing the quality of the compressions (9-14).
This fact is confirmed both by the results obtained in this
study as well as the results of previous tests, including
the use of hemodynamic measurements (13).
The next parameter is the frequency of chest com-
pressions. Guidelines for CPR recommend that chest
compressions be performed at a frequency of 100

Comparison of two chest compression techniques during infant resuscitation. A randomized, cross-over study
215
Fig. 3a-f. Quality parameters of chest compressions: a) compression depth; b) number of compressions with correct depth; c) number of
compressions fully released; d) compression rate; e) number of compressions with correct hand position; f) no flow time

216
Jacek Smereka et al.
to 120 compressions per minute. Zou et al. indicate
that an appropriate choice may be 120 compres-
sions/min (23). The recent study showed that final year
medical students have a tendency to compress the
chest too quickly, both in the standard and the innova-
tive two-thumb technique.
The study has limitations. One of the limitations is to
perform a test based on a patient simulator, however,
only this way to conduct a research experiment allows
to perform fully standardized, randomized, cross-study
trials in the conditions of cardiopulmonary resuscita-
tion (24-26). The second limitation is resuscitation based
on two-minute CPR cycles, however this is the cycle rec-
ommended by the ERC and AHA guidelines. In addition,
further studies are being conducted to show the effect of
prolonged resuscitation and individual chest compres-
sions on the quality of resuscitation parameters.
CONCLUSIONS
In the conducted simulation study carried out by
final year medical students, the use of an innova-
tive method of chest compressions was associated
with higher-quality compressions of the infant’s
chest compared to the recommendations of the
American Heart Association or the European Re-
suscitation Council.
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received/otrzymano: 05.07.2018
accepted/zaakceptowano: 26.07.2018