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A Preliminary Comparison Between Methods of Performing External Chest Compressions During Microgravity Simulation
Abstract and Figures
External chest compressions (ECCs), which form the main part of Basic Life Support (BLS), must be carried out until Advanced Life Support can commence. It is essential to perform ECCs to the correct depth and frequency to guarantee effectiveness. Due to the absence of gravity, performing ECCs during a spacefl ight is more challenging. The three main BLS methods (Fig. 1) that can be used in microgravity are the Handstand (HS), the Reverse Bear Hug (RBH) and the Evetts-Russomano (ER), which have been studied separately in parabolic fl ights (2,3). The fi ndings suggested that the depth and frequency of the ECCs achieved during the microgravity parabolas were in accordance with the guidelines set by the American Heart Association (6) and the European Resuscitation Council (4), at the time of the studies. The wellknown main limitation of a parabolic fl ight is that it gives only 22 s of weightlessness, restricting a more complete evaluation of BLS methods. The ER method, however, has been extensively studied using a body suspension device as a ground-based microgravity simulator (5). This preliminary experiment aimed to compare the three main BLS models on the performance of the ECCs during ground-based microgravity simulation.
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... Recent guidelines for CPR during spaceflight advise approaching CPR similarly to earth-based ones [8]. There are three main methods to perform chest compressions (CC) that can be used in microgravity: the Handstand (HS), the Reverse Bear Hug (RBH), and the Evetts-Russomano (ER) [9,10]. Guidelines suggest to start with the ER technique at the site of the emergency (as it allows transportation of the victim) and to shift to HS technique as soon as the victim is restrained and the surface distance allows for its application [8]. ...
... However, all tested methods perform below earth-based standards in terms of depth achieved. Even in the most optimal situation where the HS technique is used on a restrained patient, HS technique resulted in suboptimal American Journal of Emergency Medicine 53 (2022) 54-58 compression depth (44.9 ± 3.3mm), where a compression depth of between 50 and 60 mm is advised in international guidelines [8][9][10]. Manual chest compression quality deteriorates significantly within minutes even in highly trained and fit rescuers [8,11]. ...
... Our results were better than the values obtained with the three main methods to perform manual CC in microgravity, that all performed below guidelines set standards in terms of CC depth achieved and the ability to sustain compressions [13]. The HS method resulted in a mean CC depth of 47.3 ± 1.2 mm, the RBH of 41.7 ± 6.2 mm [9] and the ER showed inconsistent results ranging from 27.1 ± 7.9 mm to 42.3 ± 5.6 mm [14,15]. The use of an ACCD allowed to continuously deliver high-quality CC. ...
Introduction
Space travel is expected to grow in the near future, which could lead to a higher burden of sudden cardiac arrest (SCA) in astronauts. Current methods to perform cardiopulmonary resuscitation in microgravity perform below earth-based standards in terms of depth achieved and the ability to sustain chest compressions (CC). We hypothesised that an automated chest compression device (ACCD) delivers high-quality CC during simulated micro-and hypergravity conditions.
Methods
Data on CC depth, rate, release and position were collected continuously during a parabolic flight with alternating conditions of normogravity (1 G), hypergravity (1.8 G) and microgravity (0 G), performed on a training manikin fixed in place utilising an ACCD. Kruskal-Wallis and Mann-Withney U test were used for comparison purpose.
Results
Mechanical CC was performed continuously during the flight; no missed compressions or pauses were recorded. Mean depth of CC showed minimal but statistically significant variations in compression depth during the different phases of the parabolic flight (microgravity 49.9 ± 0.7, normogravity 49.9 ± 0.5 and hypergravity 50.1 ± 0.6 mm, p < 0.001).
Conclusion
The use of an ACCD allows continuous delivery of high-quality CC in micro- and hypergravity as experienced in parabolic flight. The decision to bring extra load for a high impact and low likelihood event should be based on specifics of its crew's mission and health status, and the establishment of standard operating procedures.
... In the following years, several experiments were conducted during parabolic flight [29][30][31] or in simulated microgravity [32][33][34][35][36] in order to identify the ideal technique of performing chest compressions. ...
... This limits the possible techniques per se to the Handstand-method, the Reverse-Bear-Hug method and the Evetts-Russomano method. Only one controlled trial compared those three methods [33], whereas other studies concentrated on one or two of the techniques [29,30,32,36] or analyzed the effectiveness mathematically [40]. ...
... Concerning the compression rate, the ER technique is superior to the RBH method (compression rate, 104.6 ± 5.4 bpm vs. 94.7 ± 5.4 bpm) [40]. The HS method resulted in compression rates of more than 120 bpm (applying the 2010 ERC guidelines) [33] and in one instance of just below 100 bpm [30]. ...
Background: With the "Artemis"-mission mankind will return to the Moon by 2024. Prolonged periods in space will not only present physical and psychological challenges to the astronauts, but also pose risks concerning the medical treatment capabilities of the crew. So far, no guideline exists for the treatment of severe medical emergencies in microgravity. We, as a international group of researchers related to the field of aerospace medicine and critical care, took on the challenge and developed a an evidence-based guideline for the arguably most severe medical emergency-cardiac arrest. Methods: After the creation of said international group, PICO questions regarding the topic cardiopulmonary resuscitation in microgravity were developed to guide the systematic literature research. Afterwards a precise search strategy was compiled which was then applied to "MEDLINE". Four thousand one hundred sixty-five findings were retrieved and consecutively screened by at least 2 reviewers. This led to 88 original publications that were acquired in full-text version and then critically appraised using the GRADE methodology. Those studies formed to basis for
... In the following years, several experiments were conducted during parabolic flight [29][30][31] or in simulated microgravity [32][33][34][35][36] in order to identify the ideal technique of performing chest compressions. ...
... This limits the possible techniques per se to the Handstand-method, the Reverse-Bear-Hug method and the Evetts-Russomano method. Only one controlled trial compared those three methods [33], whereas other studies concentrated on one or two of the techniques [29,30,32,36] or analyzed the effectiveness mathematically [40]. ...
... Concerning the compression rate, the ER technique is superior to the RBH method (compression rate, 104.6 ± 5.4 bpm vs. 94.7 ± 5.4 bpm) [40]. The HS method resulted in compression rates of more than 120 bpm (applying the 2010 ERC guidelines) [33] and in one instance of just below 100 bpm [30]. ...
Background
With the “Artemis”-mission mankind will return to the Moon by 2024. Prolonged periods in space will not only present physical and psychological challenges to the astronauts, but also pose risks concerning the medical treatment capabilities of the crew. So far, no guideline exists for the treatment of severe medical emergencies in microgravity. We, as a international group of researchers related to the field of aerospace medicine and critical care, took on the challenge and developed a an evidence-based guideline for the arguably most severe medical emergency – cardiac arrest.
Methods
After the creation of said international group, PICO questions regarding the topic cardiopulmonary resuscitation in microgravity were developed to guide the systematic literature research. Afterwards a precise search strategy was compiled which was then applied to “MEDLINE”. Four thousand one hundred sixty-five findings were retrieved and consecutively screened by at least 2 reviewers. This led to 88 original publications that were acquired in full-text version and then critically appraised using the GRADE methodology. Those studies formed to basis for the guideline recommendations that were designed by at least 2 experts on the given field. Afterwards those recommendations were subject to a consensus finding process according to the DELPHI-methodology.
Results
We recommend a differentiated approach to CPR in microgravity with a division into basic life support (BLS) and advanced life support (ALS) similar to the Earth-based guidelines. In immediate BLS, the chest compression method of choice is the Evetts-Russomano method (ER), whereas in an ALS scenario, with the patient being restrained on the Crew Medical Restraint System, the handstand method (HS) should be applied. Airway management should only be performed if at least two rescuers are present and the patient has been restrained. A supraglottic airway device should be used for airway management where crew members untrained in tracheal intubation (TI) are involved.
Discussion
CPR in microgravity is feasible and should be applied according to the Earth-based guidelines of the AHA/ERC in relation to fundamental statements, like urgent recognition and action, focus on high-quality chest compressions, compression depth and compression-ventilation ratio. However, the special circumstances presented by microgravity and spaceflight must be considered concerning central points such as rescuer position and methods for the performance of chest compressions, airway management and defibrillation.
... Der Vorteil und große Unterschied dieser Technik im Vergleich zur STD/SM liegt in der unmittelbaren Anwend-barkeit ohne weitere Hilfsmittel und dem damit verbundenen direkten Beginn der CPR. Allerdings ist das Durchführen der Thoraxkompressionen sehr anstrengend, sodass in bisherigen Untersuchungen bereits frühzeitig ein Nach lassen der Reanimationsleistung (kardialer Output) zu sehen ist [18]. Die Technik könnte sich daher für eine kurzzeitige und überbrückende Anwendung anbieten. ...
ZUSAMMENFASSUNG
Aufgrund der guten medizinischen Selektion, der guten körperlichen Konstitution und der engmaschigen, intensiven Betreuung sind relevante medizinische Probleme bei Astronauten im Weltall vergleichsweise selten. Bisher sind 5 relevante Methoden zur Durchführung von Thoraxkompressionen im Rahmen einer kardiopulmonalen Reanimation (CPR) in Schwerelosigkeit entwickelt worden. Das Ziel der vorliegenden Arbeit ist die Darstellung dieser 5 Techniken sowie das Aufzeigen von möglichen Problemen in Zusammenhang mit einer CPR im Weltall in Zukunft. Bisher liegen keine praktischen Erfahrungen zu einer Reanimation im Weltall vor. Alle bisher publizierten Studien wurden entweder im Parabelflug oder unter simulierten Bedingungen (z.B. Unterwasser oder in einem Aufhängeapparat) auf der Erde durchgeführt. Zukünftig sind, gerade für längere Raumflüge, weitere Analysen und detailliertere Vorgaben notwendig.
... Altogether a total of 3 guidelines (American Heart Association [AHA] 2000 [6], European Resuscitation Council [ERC] 2005 [12,13], and ERC 2010 [11,13]) with different requirements were used in the studies compared. In addition, not every technique was carried out in each guideline. ...
Abstract: Background: Although there have been no reported cardiac arrests in space to date, the risk of severe medical events occurring during long-duration spaceflights is a major concern. These critical events can endanger both the crew as well as the mission and include cardiac arrest, which would require cardiopulmonary resuscitation (CPR). Thus far, five methods to perform CPR in microgravity have been proposed. However, each method seems insufficient to some extent and not applicable at all locations in a spacecraft. The aim of the present study is to describe and gather data for two
new CPR methods in microgravity. Materials and Methods: A randomized, controlled trial (RCT) compared two new methods for CPR in a free-floating underwater setting. Paramedics performed chest compressions on a manikin (Ambu Man, Ambu, Germany) using two new methods for a freefloating position in a parallel-group design. The first method (Schmitz–Hinkelbein method) is similar to conventional CPR on earth, with the patient in a supine position lying on the operator’s knees forstabilization. The second method (Cologne method) is similar to the first, but chest compressions are conducted with one elbow while the other hand stabilizes the head. The main outcome parameters
included the total number of chest compressions (n) during 1 min of CPR (compression rate), the rate of correct chest compressions (%), and no-flow time (s). The study was registered on clinicaltrials.gov (NCT04354883). Results: Fifteen volunteers (age 31.0 ± 8.8) years, height 180.3 ± 7.5 cm, and weight (84.1 ± 13.2 kg) participated in this study. Compared to the Cologne method, the Schmitz–Hinkelbein method showed superiority in compression rates (100.5 ± 14.4 compressions/min), correct compression depth (65 ± 23%), and overall high rates of correct thoracic release after compression (66% high,
20% moderate, and 13% low). The Cologne method showed correct depth rates (28 ± 27%) but was associated with a lower mean compression rate (73.9 ± 25.5/min) and with lower rates of correct
thoracic release (20% high, 7% moderate, and 73% low). Conclusions: Both methods are feasible without any equipment and could enable immediate CPR during cardiac arrest in microgravity, even in a single-helper scenario. The Schmitz–Hinkelbein method appears superior and could allow the delivery of high-quality CPR immediately after cardiac arrest with sufficient quality
Introduction
Provision of critical care and resuscitation was not practical during early missions into space. Given likely advancements in commercial spaceflight and increased human presence in low Earth orbit (LEO) in the coming decades, development of these capabilities should be considered as the likelihood of emergent medical evacuation increases.
Methods
PubMed, Web of Science, Google Scholar, National Aeronautics and Space Administration (NASA) Technical Server, and Defense Technical Information Center were searched from inception to December 2018. Articles specifically addressing critical care and resuscitation during emergency medical evacuation from LEO were selected. Evidence was graded using Oxford Centre for Evidence-Based Medicine guidelines.
Results
The search resulted in 109 articles included in the review with a total of 2,177 subjects. There were two Level I systematic reviews, 33 Level II prospective studies with 647 subjects, seven Level III retrospective studies with 1,455 subjects, and two Level IV case series with four subjects. There were two Level V case reports and 63 pertinent review articles.
Discussion
The development of a medical evacuation capability is an important consideration for future missions. This review revealed potential hurdles in the design of a dedicated LEO evacuation spacecraft. The ability to provide critical care and resuscitation during transport is likely to be limited by mass, volume, cost, and re-entry forces. Stabilization and treatment of the patient should be performed prior to departure, if possible, and emphasis should be on a rapid and safe return to Earth for definitive care.
The quest for exploration is at the heart of the human psyche, and journeying to the stars is the ultimate quest. However, effective surgical and anaesthetic support will be an essential part of any human space exploration mission, so it is important to understand some of the key issues and challenges involved in this.
Hintergrund Auch wenn die frühzeitige gute medizi-nische Selektion und die engmaschige, intensive medizinische Betreuung rele-vante medizinische Probleme während des Weltraumaufenthalts unwahrschein-lich machen, besteht nichtsdestotrotz die Möglichkeit, dass ein Astronaut in Schwe-relosigkeit (Gravitation = 0G) einen Kreis-laufstillstand erleidet und reanimiert wer-den muss [10]. Seit Beginn der bemannten Raumfahrt haben sich deshalb verschie-dene Untersuchungen mit der Durchfüh-rung von Notfallprozeduren in Schwere-losigkeit beschäftigt [17]. Das Spektrum an notwendigen Behandlungen reicht da-bei von der Intubation mit verschiedenen Intubationshilfen [14] über die Möglich-keiten zur Anästhesie [8, 13] bis hin zur Durchführung von Thoraxkompressio-nen für eine Wiederbelebung. Um auf medizinische Probleme ad-äquat regieren zu können, durchlaufen Astronauten neben der technischen Spe-zialausbildung auch eine medizinische Grundausbildung (z. B. zum Crew Medical Officer, CMO). Dabei stehen v. a. auch für den medizinischen Laien erlernbare Tech-nikenzur Behandlung von akut lebensbe-drohlichen Ereignissen im Mittelpunkt. Die Palette reicht von der Beat mung mit-tels supraglottischen Atemweg shilfen über das Legen von periphervenösen und int-raossären Zugängen bishin zur Entlastung eines Spannungspneumothorax. Auch wenn die Wahrscheinlichkeit für einen Kreislaufstillstand aufgrund der gu-ten medizinischen Selektion und des zeit-lich begrenzten Aufenthalts im Weltraum momentan sehr gering ist, stellen v. a. zu-künftige Langzeitmissionen einen beson-deren Anspruch an die Notfallmedizin. » Eine besondere Rolle spielt die Mars-One-Mission Eine besondere Rolle spielt hier die aktuell in Vorbereitung befindliche Mars-One-Mission. Mit ihr werden erstmals Men-schen ohne die Möglichkeit der Rückkehr auf den Mars fliegen, um dort eine Kolo-nie zu errichten. Von großer Bedeutung in der Vorbereitung der Mission sind prak-tikable Möglichkeiten zur Behandlung le-bensbedrohlicher Erkrankungen. Eine der zentralen Fragen ist dabei die adäqua-te Durchführung einer kardiopulmona-len Reanimation (CPR) [3]. Während die CPR unter Normalbedingungen (Gravi-tation = 1 G) sehr gut erforscht und etab-liert ist, ergeben sich bei der Anwendung in Schwerelosigkeit verschiedene Proble-me. Hauptproblem stellt dabei das Feh-len der Gravitation und damit verbunden das Widerlager zur Durchführung von Thoraxkompressionen dar [9]. So würde der Versuch einer Thoraxkompression in Schwerelosigkeit lediglich zum Wegdrü-cken voneinander führen, ohne dass dabei eine hämodynamisch relevante Kompres-sion erzielt werden kann. Konventionelle Methoden, wie sie auf der Erde praktiziert werden, sind hier daher nicht möglich. Ziel der vorliegenden Untersuchung war das Zusammenstellen und Analysie-ren verschiedener, bereits bekannter und publizierter Techniken zur CPR in Schwe-relosigkeit.
Hintergrund Aufgrund der guten medizinischen Selektion, des meist jungen Alters und der engmaschigen, intensiven medizinischen Betreuung sind relevante medizinische Probleme bei Astronauten im Weltall vergleichsweise selten. Nichtsdestotrotz besteht die Möglichkeit, dass ein Astronaut in Schwerelosigkeit einen Herz-Kreislauf-Stillstand erleidet und reanimiert werden muss. Ziel der systematischen Untersuchung war die Zusammenstellung und Analyse verschiedener, bekannter und publizierter Techniken zur kardiopulmonalen Reanimation (CPR) unter den Bedingungen der Schwerelosigkeit. Material und Methoden Systematische Analyse mit definierten Kriterien in der Datenbank PubMed (http://www.pubmed.com). Verwendet wurden die Suchbegriffe („Reanimation“ oder „CPR“ oder „Resuscitation“) und („Space“ oder „Microgravity“). Ergebnisse Durch die Literatursuche mit den angegebenen Suchbegriffen wurden insgesamt 5 unterschiedliche Techniken zur kardiopulmonalen Reanimation in der Schwerelosigkeit [Microgravity (simuliert) oder Weltall (real)] identifiziert: 1) Standardtechnik, 2) Stradling-manoeuver-Technik, 3) Reverse-Bear-Hug-Technik, 4) Evetts-Russomano-Technik, 5) Handstand-Technik. Alle Studien wurden entweder im Parabelflug oder unter simulierten Bedingungen auf der Erde durchgeführt. Keine Studie wurde unter realen Bedingungen im Weltall durchgeführt. Schlussfolgerungen Hinsichtlich der Reanimationsqualität scheint die Handstand-Technik am besten geeignet zu sein, um einen Herz-Kreislauf-Stillstand in der Schwerelosigkeit zu behandeln. Bei ungünstigen räumlichen Verhältnissen und einer Nichtanwendbarkeit der Handstand-Technik stellt die Evetts-Russomano-Technik eine adäquate Alternative bei nur minimal schlechterer Reanimationsqualität dar.
If a cardiac arrest occurs in microgravity, current emergency protocols aim to treat patients via a medical restraint system within 2-4 min. It is vital that crewmembers have the ability to perform single-person cardiopulmonary resuscitation (CPR) during this period, allowing time for advanced life support to be deployed. The efficacy of the Evetts-Russomano (ER) method has been tested in 22 s of microgravity in a parabolic flight and has shown that external chest compressions (ECC) and mouth-to-mouth ventilation are possible.
There were 21 male subjects who performed both the ER method in simulated microgravity via full body suspension and at +1 Gz. The CPR mannequin was modified to provide accurate readings for ECC depth and a metronome to set the rate at 100 bpm. Heart rate, rate of perceived exertion, and angle of arm flexion were measured with an ECG, elbow electrogoniometers, and Borg scale, respectively.
The mean (+/- SD) depth of ECC in simulated microgravity was lower in each of the 3 min compared to +1 G2. The ECC depth (45.7 +/- 2.7 mm, 42.3 +/- 5.5 mm, and 41.4 +/- 5.9 mm) and rate (104.5 +/- 5.2, 105.2 +/- 4.5, and 102.4 +/- 6.6 compressions/min), however, remained within CPR guidelines during simulated microgravity over the 3-min period. Heart rate, perceived exertion, and elbow flexion of both arms increased using the ER method.
The ER method can provide adequate depth and rate of ECC in simulated microgravity for 3 min to allow time to deploy a medical restraint system. There is, however, a physiological cost associated with it and a need to use the flexion of the arms to compensate for the lack of weight.
If a cardiac arrest occurs in microgravity, the aim of current emergency procedures is to treat the patient using a medical restraint system within 2 min. The patient may require treatment while medical equipment is being deployed. The capability for one person, unaided, to successfully perform cardiopulmonary resuscitation (CPR) is, therefore, of paramount importance. A new technique has been developed whereby the practitioner encircles the thorax of the patient with his/her legs to restrain the patient to allow CPR to be performed in microgravity.
Two investigators performed both this method (during parabolic microgravity) and traditional CPR (at +1 Gz) on an instrumented CPR mannequin. The mannequin was modified to ensure accurate chest compression and ventilation measurements during microgravity.
The mean (+/-SE) depth and rate of chest compression were 44.0+/-4.99 mm and 68.3+/-17.0 compressions x min(-1) respectively. Although the mean microgravity rate of compression proved significantly less (p < 0.05) than the +1 Gz mean (97.1+/-3.4 compressions x min(-1)), chest compression depth did not differ (p > 0.05) from +1 Gz measures (43.6+/-0.59 mm). The mean (+/-SE) microgravity tidal volume (VT) was 491+/-50.4 ml, which also did not differ (p > 0.05) from +1 Gz values (507.6+/-11.5 ml).
Although difficulties in performing this method during parabolic flight primarily affected compression rate, it may be possible to conduct basic life support using this technique in any microgravity environment.
Cardiopulmonary resuscitation (CPR) in microgravity via closed chest compression is thought to be possible by several techniques. This study examined the handstand, side, and waist straddle maneuvers, and a bear hug technique in performing CPR and meeting American Heart Association (AHA) recommendations in microgravity. We also hypothesized that one rescuer using a CPR bellows adjunct device is equivalent to two rescuers.
A pre-intubated mannequin model resting on the crew medical restraint system from the International Space Station was instrumented with transducers to measure airway pressure and chest compression depth. Microgravity conditions were provided through repetitive parabolic flight on the KC-135A. On identifying the most effective position, standard two-rescuer CPR was compared with one-rescuer CPR augmented with a bellows-on-sternum CPR adjunct device (Kendall CardioVent, Kendall Medizinische Erzeugnisse GMBH, Neustadt/Donau, Germany).
Handstand position compression depth was 1.58 in +/- 0.20 in SD (4.01 cm +/- 0.51 cm), side straddle was 0.78 in +/- 0.44 in SD (1.98 cm +/- 1.12 cm), and waist straddle was 1.21 in +/- 0.47 in SD (3.07 cm +/- 1.19 cm) across rescuers with heights of 164-174 cm. Rates of compression were 98.3 +/- 6.3 SD, 100.0 +/- 3.0 SD, and 102.6 +/- 12.1 SD compressions per minute, respectively. Compression depth for one rescuer utilizing the Kendall CardioVent device in the handstand position was 1.48 in +/- 0.14 in SD (3.76 cm +/- 0.36 cm). Compression depth for two rescuers was 1.58 in +/- 0.20 in SD (4.01 cm +/- 0.51 cm) (p < 0.01).
CPR in microgravity is most reliably performed in the handstand position and meets AHA guidelines for closed chest compression depth. One-rescuer CPR incorporating the Kendall CardioVent device appears promising in microgravity. CPR adjunct devices would positively impact resuscitative procedures like CPR by small crews with inherent manpower requirements.
Updated American Heart Association guidelines
Updated American Heart Association guidelines. Respir Care
2010 ; 55 : 969.
Resting HR 71.2 6 19
- Post Vs
Post vs. Resting HR
71.2 6 19.5 ‡
65.4 6 26.1 ‡
35.7 6 10.7
MEAN ( 6 SD) OF DEPTH AND FREQUENCY OF ECC, THE DIFFERENCE BETWEEN POST AND RESTING HEART RATES (HR)
- And Borg
- Scores
TABLE I. MEAN ( 6 SD) OF DEPTH AND FREQUENCY OF ECC, THE
DIFFERENCE BETWEEN POST AND RESTING HEART RATES (HR),
AND BORG SCALE SCORES.
Evaluation of a novel basic life support method in simulated microgravity
- L Rehnberg
- T Russomano
- F Falc à O
- F Campos
- S N Evetts
Rehnberg L, Russomano T. Falc ã o F, Campos F, Evetts SN.
Evaluation of a novel basic life support method in simulated
microgravity. Aviat Space Environ Med 2011 ; 82 : 104 -10.