Abstracts

Endotracheal Intubation Attempts During Neonatal Resuscitation: Success Rates, Duration, and Adverse Effects

Colm P.F. O'Donnell, MD, MRCPI, MRCPCHa,b, C. Omar F. Kamlin, MB, MRCP, MRCPCHa, Peter G. Davis, MD, FRACPa,b and Colin J. Morley, MD, FRACP, FRCPCHa,c
PEDIATRICS Vol. 117 No. 1 January 2006, pp. e16-e21

OBJECTIVE. Endotracheal intubation of newborn infants is a mandatory competence for many pediatric trainees. The Neonatal Resuscitation Program recommends a 20-second limit for intubation attempts. Intubation attempts by junior doctors are frequently unsuccessful, and many infants are intubated between 20 and 30 seconds without apparent adverse effect. Little is known about the proficiency of more senior medical staff, the time taken to determine endotracheal tube (ETT) position, or the effects of attempted intubation on infants' heart rate (HR) and oxygen saturation (SpO2) in the delivery room (DR). The objectives of this study were to determine (1) the success rates and duration of intubation attempts during DR resuscitation, (2) whether experience is associated with greater success rates and shorter time taken to intubate, (3) the time taken to identify ETT position after intubation, and (4) the frequency with which infants deteriorated during intubation attempts and the time at which this occurred. METHODS. We reviewed videos of DR resuscitations; identified whether intubation was attempted; and, when attempted, whether intubation was attempted by a resident, a fellow, or a consultant. We defined the duration of an intubation attempt as the time from the introduction of the laryngoscope blade to the mouth to its removal, regardless of whether an ETT was introduced. We determined the time from removal of the laryngoscope to the clinicians' decision as to whether the intubation was successful and noted the basis on which this decision was made (clinical assessment, flow signals, or exhaled carbon dioxide [ETCO2] detection). We determined success according to clinical signs in all cases and used flow signals that were obtained during ventilation via the ETT or ETCO2 when available. When neither was available, the chest radiograph on admission to the NICU was reviewed. For infants who were monitored with pulse oximetry, we determined their HR and SpO2 before the intubation attempt. We then determined whether either or both fell by 10% during the attempt and, if so, at what time it occurred.

RESULTS. We reviewed 122 video recordings in which orotracheal intubation was attempted 60 times in 31 infants. We secondarily verified ETT position using flow signals, ETCO2, or chest radiographs after 94% of attempts in which an ETT was introduced. Thirty-seven (62%) attempts were successful. Success rates and mean (SD) time to intubate successfully by group were as follows: residents: 24%, 49 seconds (13 seconds); fellows: 78%, 32 seconds (13 seconds); and consultants: 86%, 25 seconds (17 seconds). Of the 23 unsuccessful attempts, 13 were abandoned without an attempt to pass an ETT and 10 were placed incorrectly. The time to determine ETT position in the DR was longer when clinical assessment alone was used. Infants who were monitored with oximetry deteriorated during nearly half of the intubation attempts. Deterioration seemed more likely when HR and SpO2 were low before the attempt.

CONCLUSIONS. Intubation attempts often are unsuccessful, and successful attempts frequently take >30 seconds. Greater experience is associated with greater success rates and shorter duration of successful attempts. Flow signals and ETCO2 may be useful in determining ETT position more quickly than clinical assessment alone. Infants frequently deteriorate during intubation attempts. Improved monitoring of infants who are resuscitated in the DR is desirable.

A Survey of Delivery Room Resuscitation Practices in the United States

Tina A. Leone, MD, Wade Rich, RRT and Neil N. Finer, MD
PEDIATRICS Vol. 117 No. 2 February 2006, pp. e164-e175

Objective. To determine current resuscitation practices of neonatologists in the United States.
METHODS. A 15-question survey was developed and mailed to neonatal directors in May 2004.

RESULTS. Of the total of 797 surveys mailed, 84 were returned undeliverable or unanswered and 450 were returned completed (63% response rate). Respondents were mainly (70%) from level III NICUs. Most programs resuscitate newborns in the delivery room (83%), rather than in a separate room. The number and background of individuals attending deliveries vary greatly, with 31% of programs having <3 individuals attending deliveries. Flow-inflating bags are most commonly used (51%), followed by self-inflating bags (40%) and T-piece resuscitators (14%). Pulse oximeters are used during resuscitation by 52% of programs, and 23% of respondents indicated that there was a useful signal within 1 minute after application. Blenders are available for 42% of programs, of which 77% use pure oxygen for the initial resuscitation and 68% use oximeters to alter the fraction of inspired oxygen. Thirty-two percent of programs use carbon dioxide detectors to confirm intubation, 48% routinely and 43% when there is difficulty confirming intubation. Preterm infants are wrapped with plastic wrap to prevent heat loss in 29% of programs, of which 77% dry the infant before wrap application. A majority of programs (76%) attempt to provide continuous positive airway pressure or positive end expiratory pressure (PEEP) during resuscitation, most commonly with a flow-inflating bag (58%), followed by a self-inflating bag with PEEP valve (19%) and T-piece resuscitator (16%). A level of 5 cm H2O is used by 55% of programs.

CONCLUSIONS. Substantial variations exist in neonatal resuscitation practices, some of which are not addressed in standard guidelines. Future guidelines should include recommendations regarding the use of blenders, oximeters, continuous positive airway pressure/PEEP, and plastic wrap during resuscitation.

¿Están justificadas las dosis elevadas de adrenalina en la parada cardiorrespiratoria en niños?

A Rodríguez Núñeza C Garcíab J López-Herce Cidc Grupo de Estudio de la Parada Cardiorrespiratoria en Pediatría
An Pediatr (Barc) 2005; 62: 113 - 116

Objetivo. Estudiar si las dosis elevadas de adrenalina por vía intravenosa o intraósea consiguen mayor supervivencia que las dosis convencionales en niños con parada cardiorrespiratoria (PCR).

Material y métodos. Se realizó un estudio prospectivo multicéntrico durante 18 meses, en el que se recogieron, siguiendo las recomendaciones internacionales (estilo Utstein), los datos de reanimación cardiopulmonar en 283 niños. En un análisis secundario se analizó la supervivencia de 92 niños a los que se administró adrenalina por vía intravenosa o intraósea.

Resultados. En 12 pacientes se administraron una o más dosis convencionales de adrenalina (0,01 mg/kg) y en 80 casos se administró una primera dosis convencional, seguida de una o más dosis altas (0,1 mg/kg). La edad y el peso de los niños que recibieron dosis convencional era mayor que los que recibieron dosis altas (97,1 6 70,5 meses frente a 29,9 6 36,9 meses, p 5 0,03, y 24,7 6 20,8 kg frente a 11,9 6 8,9 kg, p 5 0,037, respectivamente). El número de dosis recibidas por el grupo de dosis convencional fue menor que en el grupo de dosis alta (4 6 4 dosis frente a 5,4 6 3,4 dosis, p 5 0,01). No se observaron diferencias significativas en relación al lugar y tipo de parada, el ritmo electrocardiográfico inicial, la recuperación de la circulación espontánea, el tiempo total de reanimación, el estado neurológico al final de la parada y la supervivencia al alta del hospital y después de un año.

Conclusión. Aunque el presente estudio tiene limitaciones importantes, los resultados sugieren que las dosis elevadas de adrenalina no mejoran la supervivencia de la PCR en niños.

Palabras clave: Adrenalina. Reanimación cardiopulmonar. Parada cardiorrespiratoria. Pediatría. Niños

CPR for children: one hand or two?

Alastair G.M. Stevensona, , , John McGowanb, Aled L. Evansc and Colin A. Graham. Resuscitation
Article in Press

Aims:
Current guidelines for chest compressions in CPR advocate a one handed technique in children (1–8 years old) and a two handed technique in adults (>8 years old). No previous study has examined whether these two techniques generate different compression pressures. This study assesses the relative difference in intrathoracic compression pressures generated by one- and two handed chest compression techniques in a paediatric manikin.

Methods:
Randomised crossover design. Subjects performed both types of chest compressions on an adapted paediatric resuscitation manikin connected to a pressure transducer and personal computer. Ethical approval was granted.

Results:
A 30 volunteer subjects (9 male, 21 female) participated in the study. Their mean age was 30.8 years (S.D. 8.6), and mean weight was 70.5 kg (S.D. 12.8). The mean compression pressure was 86.6 mmHg (S.D. 13.68) for two handed and 75.1 mmHg (S.D. 12.02) for one handed (P < 0.001, paired t-test). The average peak compression pressure was 133.5 mmHg (S.D. 26.36) for two handed and 116.8 mmHg (S.D. 21.48) for one handed (P = 0.001, paired t-test); 29 found the two handed technique easier to perform.

Conclusion:
Two handed chest compression CPR seems to be easier to perform on a paediatric resuscitation manikin and produces significantly higher mean and peak pressures. Further work is needed to determine the comparative effects on children and which technique produces better clinical outcomes.

Keywords: Children; Cardiopulmonary resuscitation; Chest compressions; Mannequin; Training

How to become an under 11 rescuer: a practical method to teach first aid to primary schoolchildren

Riccardo Lubranoa, Stefano Romeroa, Pietro Scoppia, Guido Cocchib, Simonetta Baroncinib, Marco Ellic, Manuela Turbaccid, Simona Scatenia, Elisabetta Travassoa, Rossella Benedettie, Sebastian Cristaldia and Rossella Moscatellif . Resuscitation
Article in Press

It has been calculated that, on average, 20% of the population should be trained to provide first aid, if a significant reduction of mortality is to be achieved. However, wide dissemination of the principles of emergency care poses a series of difficulties. As a partial solution, we have designed a first aid training course for children aged 8–11 years in their last three courses at primary school. According to the Italian school system, classes in primary school are indicated as I through V, from start to ending. The course addresses three issues: the broken tooth, nose bleeding and paediatric basic life support (PBLS). The course is divided into 17 didactic modules: each module contains a theoretical lecture, a practical demonstration by the trainer and a session for the trainees to practice under supervision. The aim of the study was to evaluate the benefit of teaching emergency procedures including practical sessions for pupils in primary schools. Four hundred and sixty-nine children were enrolled: the evaluation consisted of a 13 question multiple-choice written test taken at the end of the theoretical session and a semi-structured test at one month. Two hundred and seventy-one children attended to the theoretical lesson only, without going through the practical session (Group A), while the remaining 189 children completed the practical training (Group B). The outcome of the evaluation demonstrates that older children (in their V school class) score better than those in their IV and III class (p < 0.001). However, when comparing Group A and Group B in each class, the children that had also been exposed to the practical training (Group B) scored significantly better (VB versus VA p < 0.001; IVB versus IVA p < 0.001; IIIB versus IIIA p < 0.01).
In conclusion, this proposed method of teaching emergency first aid could be successful in training primary school children. The permanent integration of the subject into the core curriculum of primary schools, and extended to higher school levels, could help in disseminating the culture of emergency care in the general population.

Keywords: Education; Child; Schools; Basic life support

Long-term outcome of paediatric cardiorespiratory arrest in Spain

Jesús López-Herce, Cristina García, Antonio Rodríguez-Núñez, , Pedro Domínguez, Angel Carrillo, Custodio Calvo, Miguel Angel Delgado and for the Spanish Study Group of Cardiopulmonary Arrest in Children. Resuscitation
Volume 64, Issue 1 , January 2005, Pages 79-85

Objective:
To analyse the final outcome of cardiorespiratory arrest (CRA) in children and the neurological and functional state of survivors at 1 year.

Methods:
An 18-month prospective, multicentre study analysing out-of-hospital and in-hospital CRA in children was carried out; 283 children between 7 days and 17 years of age were included. CRA and resuscitation data were registered according to Utstein style. The outcome variables were: sustained return of spontaneous circulation (initial survival), and survival at 1 year (final survival). The status of survivors was evaluated by means of the paediatric cerebral performance category (PCPC) scale and the paediatric overall performance category (POPC) scale at Paediatric Intensive Care Unit discharge, at hospital discharge, and at 1 year follow-up.

Results:
In 283 children, 311 CRA episodes, 73 respiratory arrests (23.5%) and 238 cardiac arrests (76.5%) were analysed. Seventeen children suffered more than one CRA episode (range: 2–6). The initial survival was 60.2% and 1-year survival was 33.2%. The final survival was significantly higher in respiratory arrest than in cardiac arrest patients (70.0% versus 21.1%) (P < 0.0001). After 1 year follow-up, 87.3% of patients had scores 1 or 2 on the PCPC scale and 84.0% had scores 1 or 2 in the POPC scale; these results indicate that 1 year after CRA, the majority of survivors had normal neurological and functional status or showed only mild disability.

Conclusions:
Prognosis of CRA in children continues to be poor in terms of survival but quite good in terms of neurological and functional status among survivors. Additional strategies and efforts are needed to improve the short-term prognosis of paediatric CRA. However, the long-term outcome of survivors is reassuring.

Keywords: Child; Cardiac arrest; Respiratory arrest; Resuscitation; Cardiopulmonary resuscitation; Outcome

Characteristics and outcome among children suffering from out of hospital cardiac arrest in Sweden

J. Herlitza, J. Engdahla, L. Svenssonb, M. Youngc, K.-A. Ängquistd and S. Holmberga. Resuscitation
Volume 64, Issue 1 , January 2005, Pages 37-40

Aim:
To evaluate the characteristics, outcome and prognostic factors among children suffering from out of hospital cardiac arrest in Sweden.

Methods:
Patients aged below 18 years suffering from out of hospital cardiac arrest which were not crew witnessed and included in the Swedish cardiac arrest registry were included in the survey. This survey included the period 1990–2001 and 60 ambulance organisations covering 85% of the Swedish population (8 million inhabitants).

Results:
In all 457 children participated in the survey of which 32% were bystander witnessed and 68% received bystander CPR. Ventricular fibrillation was found in 6% of the cases. The overall survival to 1 month was 4%. The aetiology was sudden infant death syndrome in 34% and cardiac in 11%. When in a multivariate analysis considering age, sex, witnessed status, bystander CPR, initial rhythm, aetiology and the interval between call for, and arrival of, the ambulance and place of arrest only one appeared as an independent predictor of an increased chance of surviving cardiac arrest occurring outside home (adjusted odds ratio 8.7; 95% CL 2.2–58.1).

Conclusion:
Among children suffering from out of hospital cardiac arrest in Sweden that were not crew witnessed, the overall survival is low (4%). The chance of survival appears to be markedly increased if the arrest occurs outside the patients home compared with at home. No other strong predictors for an increased chance of survival could be demonstrated.

Characteristics and outcome of cardiorespiratory arrest in children

Jesús López-Herce,, Cristina García, Pedro Domínguez, Angel Carrillo, Antonio Rodríguez-Núñez, Custodio Calvo, Miguel Angel Delgado and for the Spanish Study Group of Cardiopulmonary Arrest in Children. Resuscitation Volume 63, Issue 3 , December 2004, Pages 311-320

Objetivo: Analizar las características y resultados actuales del paro cardiorrespiratorio en niños en España. Diseño: Estudio multicéntrico, prospectivo de 18 meses de duración, analizando el paro cardiorrespiratorio intra y extrahospitalario en niños. Pacientes y métodos: 283 niños entre 7 días y 17 años de edad con paro cardiorrespiratorio. Los datos fueron registrados de acuerdo con el estilo Utstein. Las variables de resultado fueron el retorno a circulación espontánea sostenida (sobrevida inicial), sobrevida a un año de plazo (sobrevida final). Se estudiaron 311 episodios de paro cardiorrespiratorio, compuestos de 70 paros respiratorios y 241 paros cardíacos en 283 niños. Los accidentes fueron la causa mas frecuente de paro cardíaco extrahospitalario (40%), y la enfermedad cardiaca fue la causa principal (31%) de paro intrahospitalario. La sobrevida inicial fue de 60.2% y a un año fue de 33.2%. La sobrevida final fue mas alta en pacientes con paro respiratorio (70%) que en pacientes con paro cardíaco (21.1%) (P < 0.0001). Aunque muchos factores individuales se correlacionan con la mortalidad, el análisis de regresión logística multivariable reveló que el mejor indicador de mortalidad fue la duración de la resucitación cardiopulmonar por encima de 20 minutos (odds ratio: 10.35; 95% CI 4.59–23.32). Conclusiones: En España, la mortalidad actual del paro cardiorrespiratorio en niños sigue alta. La sobrevida después del paro respiratorio es significativamente más alta que después del paro cardiaco. La duración de las maniobras de reanimación cardiopulmonar es el mejor indicador de mortalidad del paro cardiorrespiratorio en niños.

Drowning: a review of epidemiology, pathophysiology, treatment and prevention

Frédéric Salomez and Jean-Louis Vincent. Resuscitation
Volume 63, Issue 3 , December 2004, Pages 261-268

La asfixia por inmersión, a pesar de ser frecuentemente prevenible, sigue siendo una de las causas principales de muerte accidental, especialmente en niños. Nuevas definiciones clasifican la asfixia por inmersión como el proceso de experimentar insuficiencia respiratoria por la inmersión o sumersión en un líquido. El aspecto fisiopatológico en la asfixia por inmersión es la hipoxia. Un pronóstico neurológico preciso no puede ser planteado a partir de la presentación clínica inicial, ni por exámenes radiológicos, de laboratorio o electrofisiológicos. Intentos de preanimación prontos y agresivos son cruciales para sobrevida óptima. Este articulo revisa la epidemiología, la fisiopatología, el tratamiento y la prevención de en la asfixia por inmersión.

Neonatal resuscitation on air: it is time to turn down the oxygen tanks?

Georg Hansmann
Lancet 2004; 364: 1293-94

Participants of the Guidelines 2000 Conference on Cardiopulmonary Resuscitation and Emergency Cardiac Care1 agreed that the biochemical findings associated with pure-oxygen resuscitation of newborn infants were of uncertain clinical significance and insufficient to establish harm.2 If a baby requires assisted ventilation today, the international guidelines1 continue to recommend the use of 100% oxygen. Vento et al3,4 found that a brief oxygen exposure of only a few minutes during resuscitation exacerbates oxidative stress up to 4 weeks after birth. High-oxygen resuscitation impairs cerebral blood flow in newborns,5 promotes reperfusion injury, and causes brain damage in animal models.6

"The key to successful neonatal resuscitation is establishment of adequate ventilation",1 but do we then need pure oxygen to open the door? In today's Lancet, Peter Davis and colleagues compare air with 100% oxygen for the resuscitation of newborn infants. They did a meta-analysis of five prospective trials (two randomised, three quasi-randomised; two blinded, three unblinded)3,4,7-9 comprising 1302 infants at birth (on average >37 gestational weeks and >2400 g in each trial). In the three unblinded studies,7-9 a fourth of the patients initially ventilated with air received 100% oxygen as back-up on "treatment failure" (90 s after birth), but were assigned to the air group. The pooled failure rate was even slightly lower in the air group (27·3% vs 28·5%) and so argues against the assumption that ventilation with air actually caused treatment failure. Newborn infants resuscitated with air did not have a higher risk of hypoxic-ischaemic encephalopathy compared with those ventilated with 100% oxygen. Although none of the individual trials revealed a difference in mortality at postnatal day 7 and/or 28, the pooled analysis shows a significant benefit for babies resuscitated with air (relative risk 0·71). Davis and colleagues conclude with caution that, for term and near-term infants in the delivery room, air should be the initial gas used, with oxygen as a backup if there is failure to respond to initial resuscitation.

This conclusion is supported by another meta-analysis10 on the data from five quasi-randomised studies.4,7-9,11 Saugstad et al reviewed four trials4,7-9 that were also analysed by Davis, but in addition included a large database in a Spanish review article11 that was not a prospectively planned trial (Vento M, personal communication). In a total of 1737 resuscitated newborn infants, neonatal mortality was 8% versus 13%, which suggests a highly significant decrease by 40% in the infants resuscitated with air.10 Saugstad et al10 could analyse death after 28 days of life for all five studies and had a higher end-number of enrolled infants. This difference might explain the more distinct mortality reduction in Saugstad et al10 compared with Davis and colleagues' meta-analysis.

Do depressed newborn infants just need "fresh air" instead of "toxic oxygen"? The five trials3,4,7-9 and meta-analyses have considerable limitations and thus the answer is not that simple. First, the included infants are not representative of all depressed babies at birth. Most of the resuscitated newborns had rapidly increasing Apgar values (>4 at 5 min.) and an umbilical artery pH over 7·0 (ie, they did not belong to the group of severely depressed newborn infants12 that profoundly contributes to neonatal mortality13). We have no information how many infants had had meconium aspiration, fulminant sepsis, severe asphyxia, and other conditions that often cause diffusion impairment and persistent pulmonary hypertension of the newborn.2 These newborns would probably benefit from higher concentrations of inspired oxygen because of its vasodilative action in the pulmonary circulation. We also do not know whether the results of the meta-analysis can be applied to newborns at different gestational ages. Recent studies have suggested that long-accepted targets of oxygen saturations for preterm infants in their first weeks of life might be too high.14-16 Second, in the five trials analysed by Davis and colleagues, most infants were recruited in developing countries with uncertain monitoring and limited treatment options prenatally and postnatally. It is uncertain, therefore, whether the results can be applied to hospitals with more resources. Third, a meta-analysis can be misleading if it pools the primary outcome "death" from different time points. For their meta-analysis, Davis and colleagues used the latest follow-up, which occurred after the 7th or 28th day of life.

The outlined limitations preclude generalisation and demand caution when applying the new findings, but the following tentative considerations seem reasonable. Because 100% oxygen is not more effective than room air8 and most likely harmful in newborn resuscitation (higher mortality in two meta-analyses, excessive oxidative stress in two prospective trials,3,4 prolongation of positive pressure ventilation and therefore barotrauma2), there is no reason to use 100% oxygen as a first-line and initial gas in the delivery room. On the other hand, we do not know whether ventilation with 30, 40, or 50% oxygen had prevented treatment failure in the moderately depressed newborns initially ventilated with air or had been accompanied by an increase in neonatal mortality, as seen in the pooled groups treated with 100% oxygen. On the basis of the existing data, air can be the initial gas to be used for the resuscitation of moderately depressed newborn infants at or near term. Adjustable oxygen supply (oxygen blenders) as back-up on treatment failure with air must be available at any time. Due to the lack of convincing data, we must not provide air to all depressed newly born infants regardless of the cause and severity of asphyxia.17 The same caution applies to older infants outside the delivery room. Special neonatal emergencies commonly associated with impaired lung function and persistent pulmonary hypertension of the newborn, such as severe asphyxia, fulminant sepsis, meconium aspiration, and congenital diaphragmatic hernia, might require oxygen concentrations up to 100% immediately after birth.2

Obviously, there is the future need for immediate and continuous monitoring of oxygen saturation and heart rate via pulsoximetry in the delivery room,18 and the need to vary inspired oxygen concentrations based on the individual status of newly born infants (ie, tailored oxygen resuscitation). When providing additional oxygen, health-care providers should keep in mind that oxygen saturation, if kept above 92%, is not reliable in detecting hyperoxia.19 According to a worldwide survey, 20 of 40 centres still use 100% oxygen for the resuscitation of all babies at delivery, whereas the remaining centres have already changed their standards and use lower oxygen concentrations.20 Now we should move forward and do adequate multicentre trials on intermediate and variable oxygen concentrations guided by pulsoximetric monitoring, thereby stratifying for gestational age and eliminating confounding variables such as cause of vital depression, place of birth, and available resources. Moreover, additional and sufficient data on the long-term outcome of resuscitated newborn infants is needed.

The evidence for mortality reduction with air is striking and will have widespread impact on the management and outcome of depressed newborn infants. At the upcoming Evidence Evaluation Conference in 2005, experts might attend to the new data, alter the guidelines for neonatal resuscitation carefully, set new goals, and make suggestions about how to achieve, maintain, and monitor normoxaemia in depressed infants at birth.

Effect of intravenous corticosteroids on death within 14 days in 10 008 adults with clinically significant head injury (MRC CRASH trial): randomised placebo-controlled trial

CRASH trial collaborators
Lancet 2004; 364: 1321-28

'There is no reduction in mortality with methylprednisolone in the 2 weeks after head injury'

Every year, millions of people around the world are treated for head injury–a major cause of death and disability in children and young adults. For more than 30 years, corticosteroids such as methylprednisolone have been used to treat such injuries. However, systematic reviews have questioned the use of these drugs. The CRASH trial collaborators did a randomised trial in more than 10 000 adults with head injury to find out if the death rate fell with corticosteroids within 2 weeks of injury. In fact, they noted an increase in the risk of death in patients taking methylprednisolone and the trial was stopped early. In a Comment paper, Stefan Sauerland and Marc Maegele say these findings are alarming and calculate that about 10 000 patients with brain injury could have lost their life by taking these drugs.

Percutaneous transcricoid jet ventilation compared with surgical cricothyroidotomy in a sheep airway salvage model

Seth Manoach, , a, Chalene Corinaldia, Lorenzo Paladinoa, Robert Schulzeb, Jean Charchafliehc, Jesse Lewina, Robert Glattera, Bruce Scharfb and Richard SinertaResuscitation Volume 62, Issue 1 , July 2004, Pages 79-87

Background: We developed a large animal model of the "cannot intubate/cannot ventilate" (CNI/V) scenario to compare percutaneous transcricoid manual jet ventilation (MJV) with surgical cricothyroidotomy (SC). Methods: Twelve sheep weighing 40–80 kg were assigned to MJV or SC groups. After sedation, intubation, and line placement, CNI/V was simulated by removing the tracheal tube and inducing paralysis with vecuronium. When SaO2 reached 80% (t=0), MJV catheter insertion or SC was initiated. Upon successful airway placement, ventilation began using 100% oxygen at 20 breaths/min. MJV was administered at 50 psi. HR, BP, SaO2, pH, PCO2, and PO2 were recorded at t=0, 30, 60, 90, 120, 150, 180, 300, 600, and 1200 s. Data were reported as mean±S.E.M. over the whole observation period. Baseline values were compared using Student’s t-tests. Repeated-values ANOVA was used for post-procedure group comparisons. Statistical tests were two-tailed and alpha was set at 0.05. Results: Body weights were not significantly (P=0.08) different between MJV (65±6 kg) and SC (52±3 kg) groups. Baseline respiratory and hemodynamic variables were also not significantly different. Median procedure time for MJV (20 s) and SC (24 s) was not significantly (P=0.69) different. Post-procedure values were not significantly different for SaO2 (P=0.65), pH (P=0.70), PCO2 (P=0.47), PO2 (P=0.84), MAP (P=0.09), or HR (P=0.16) over the entire 20 min resuscitation period. Conclusion: Using a realistic model of CNI/V we found no difference in respiratory or hemodynamic variables between MJV and SC. Adequate ventilation and perfusion was maintained solely by MJV for up to 20 min

Vasopressin versus continuous adrenaline during experimental cardiopulmonary resuscitation

Jakob Johansson, , Rolf Gedeborg and Sten Rubertsson
Resuscitation Volume 62, Issue 1 , July 2004, Pages 61-69

Objective: To evaluate the effects of a bolus dose of vasopressin compared to continuous adrenaline (epinephrine) infusion on vital organ blood flow during cardiopulmonary resuscitation (CPR). Methods: Ventricular fibrillation was induced in 24 anaesthetised pigs. After a 5-min non-intervention interval, CPR was started. After 2 min of CPR the animals were randomly assigned to receive either vasopressin (0.4 U/kg) or adrenaline (bolus of 20 g/kg followed by continuous infusion of 10 g/(kg min)). Defibrillation was attempted after 9 min of CPR. Results: Vasopressin generated higher cortical cerebral blood flow (P<0.001) and lower cerebral oxygen extraction (P<0.001) during CPR compared to continuous adrenaline. Coronary perfusion pressure during CPR was higher in vasopressin-treated pigs (P<0.001) and successful resuscitation was achieved in 12/12 in the vasopressin group versus 5/12 in the adrenaline group (P=0.005). Conclusions: In this experimental model, vasopressin caused a greater increase in cortical cerebral blood flow and lower cerebral oxygen extraction during CPR compared to continuous adrenaline. Furthermore, vasopressin generated higher coronary perfusion pressure and increased the likelihood of restoring spontaneous circulation.

Laryngeal mask airway: is the management of neonates requiring positive pressure ventilation at birth changing?

Daniele Trevisanuto, , a, Massimo Micagliob, Mariangela Pittonb, Mariella Magarottoa, Daniele Pivaa and Vincenzo Zanardoa
Resuscitation Volume 62, Issue 2 , August 2004, Pages 151-157

Objective: To evaluate the impact of the laryngeal mask airway (LMA) on neonatal resuscitation policy. Design: We analyzed retrospectively the records of neonates requiring positive pressure ventilation (PPV) at birth before (1996) and after (2000) the introduction of the LMA into our delivery suites. In addition, the outcome of neonates treated with the LMA was compared with that of neonates matched for gestational age and mode of delivery who were resuscitated using a face mask. Results: During the year 2000, 95 out of 380 (25%) resuscitated neonates were treated with the LMA. The LMA was effective in 94 out of 95 (99%) of these infants. Over the same period, the percentage of neonates receiving tracheal intubation (TI) at birth (34%) was significantly reduced compared with the figure for 1996 (67%). There were no reported complications associated with the use of the LMA. Seventy-four out of the 95 neonates treated with the LMA were considered suitable for matching for gestational age and mode of delivery with 74 neonates treated with a face mask. No differences were found between the two groups for birth weight, Apgar scores, need for tracheal intubation, need for admission to the Neonatal Intensive Care Unit (NICU), primary diagnosis at discharge and primary outcomes. The LMA provided effective ventilation in four neonates in whom the face mask failed. Conclusions: The LMA is changing neonatal resuscitation practice in our Institution. Our data suggest that it is a safe and useful alternative method for respiratory support in neonates requiring PPV at birth, which merits further study.

Attenuated adult biphasic shocks compared with weight-based monophasic shocks in a swine model of prolonged pediatric ventricular fibrillation

Robert A. Berg, Fred W. Chapmand, Marc D. Berga, , Ronald W. Hilwigb, Isabelle Banvilled, Robert G. Walkerd, Richard C. Novad, Duane Sherrillc and Karl B. Kernb. Resuscitation. Volume 61, Issue 2 , May 2004, Pages 189-197

Aim: To compare the safety and efficacy of attenuated adult biphasic shocks with standard monophasic weight-based shocks in a piglet model of prolonged prehospital ventricular fibrillation (VF). Background: If attenuated adult shocks are safe and effective for prehospital pediatric VF, automated external defibrillators (AEDs) can be easily adapted for pediatric use. Methods: After 7 min of untreated VF, piglets were randomized to treatment with attenuated adult biphasic shocks or weight-based monophasic shocks. The attenuated adult biphasic group received 200/300/360 J shocks, attenuated by specialized pediatric electrodes to 51/78/81 J and the monophasic weight-based control group received 2/4/4 J/kg shocks. Forty-eight female piglets were studied, 16 in each of three weight categories: 4 kg (neonatal), 14 kg (younger child) and 24 kg (older child). The primary outcome measures of efficacy and safety were 24 h survival with good neurological outcome and post-resuscitation left ventricular ejection fraction (LVEF), respectively. Results: For the 24 kg piglets, attenuated adult biphasic shocks resulted in superior 24 h survival with good neurological outcome (6/8 versus 0/8, P<0.001) and greater LVEF 4 h post-resuscitation (34±4% versus 18±5%, P<0.05). For the 14 and 4 kg piglets, 24 h survival with good neurological outcome occurred in 7/8 versus 5/8 and 7/8 versus 3/8, respectively, and LVEF 4 h post-resuscitation was 30±3% versus 36±6% and 30±3% versus 22±4%, respectively. Conclusions: The escalating attenuated adult biphasic dosage strategy was at least as safe and effective as the standard weight-based monophasic dose over a wide range of weights in this piglet model of prehospital VF. This work supports the concept of using an attenuated adult biphasic dosage in children.

A Prospective, Population-Based Study of the Epidemiology and Outcome of Out-of-Hospital Pediatric Cardiopulmonary Arrest

K.D.Young et al. Pediatrics 2004;114:157-164

Background. This study reports the epidemiologic features, survival rates, and neurologic outcomes of the largest population-based series of pediatric out-of-hospital cardiopulmonary arrest patients with prospectively collected data.
Methods. Secondary analysis of data from a prospective, interventional trial of out-of-hospital pediatric airway management conducted from 1994 to 1997 (Gausche M, Lewis RJ, Stratton SJ, et al. JAMA. 2000;283:783-790). Consecutive out-of-hospital patients from 2 large urban counties in California <12 years old or 40 kg in bodyweight who were determined by paramedics to be pulseless and apneic were included. Main outcome measures included survival to hospital discharge, patient demographics, arrest etiology, arrest rhythm, event intervals, and neurologic outcomes.

Results. In 599 patients, 601 events were studied (54% were <1 year old, 58% were male). Return of spontaneous circulation was achieved in 29%; 25% were admitted to the hospital, and 8.6% (51) survived to hospital discharge. The most prevalent etiologies were sudden infant death syndrome and trauma; these resulted in relatively higher mortality. Respiratory etiologies and submersions followed; these resulted in relatively lower mortality. Twenty-six percent of the arrests were witnessed by citizens, and an additional 8% were witnessed by rescue personnel. Witnessed arrests had a higher survival rate (16%). Thirty-one percent of patients received bystander cardiopulmonary resuscitation, which was not demonstrated to result in improved survival rates. Arrest rhythms were asystole (67%), pulseless electrical activity (24%), and ventricular fibrillation (9%); children with the latter 2 rhythms had better survival rates. One third of the survivors (16 of 51) had good neurologic outcome, none of whom received >3 doses of epinephrine or were resuscitated for >31 minutes in the emergency department.

Conclusions. The 8.6% survival rate after out-of-hospital pediatric cardiopulmonary arrest is poor. Administration of >3 doses of epinephrine or prolonged resuscitation is futile.

Hyperventilation during cardiac arrest

Stephen Pitts, Arthur Kellermann
www.thelancet.com Vol 364 July 24, 2004

Cardiac arrest is often studied in controlled laboratory environments. Real life is different: when the alarm sounds, we rush to the scene uncertain of what we will find. The suddenness of these events and the high stakes involved produces an adrenaline-driven arousal response. As a result, we do everything fast, including, perhaps, bag-valve ventilation. In fact, the simple task of squeezing the bag is often assigned to the most junior person on the resuscitation team, while more experienced members focus on securing the airway, inserting lines, administering drugs, and identifying cardiac rhythms. Rescuers know that cardiac arrest produces a profound acidosis, and most are aware of studies which suggest that hypercarbia reduces the effectiveness of epinephrine.1 Therefore, many rescuers probably believe that hyperventilation is not harmful, and may even be beneficial in many instances. This belief may explain why many team leaders are quick to correct a team member for bagging too slow, but slow to chide one for bagging too fast.
There are, however, several reasons to believe that hyperventilation might be deleterious in the setting of cardiac arrest, and may even be more harmful than hypoventilation. First, in unintubated patients, rescue breathing reduces the frequency of chest compressions. Second, the increased intrathoracic pressure produced by positive-pressure ventilation reduces inflow of blood to the right side of the heart, reducing cardiac output.2 Third, coronary perfusion during diastole–an important determinant of return of spontaneous circulation in cardiac arrest–requires a pressure gradient between the aorta and right ventricle.3 This pressure gradient is reduced by intrathoracic pressure. Fourth, respiratory alkalosis shifts the oxygen-haemoglobin dissociation curve to the left, reducing oxygen delivery to tissue. And fifth, hyperventilation causes cerebral vasoconstruction, which can significantly reduce brain perfusion.4 Cerebral vasoconstriction can be particularly problematic in low-flow states, such as during cardiopulmonary resuscitation.

The adverse physiological impact of high intrathoracic pressure has been investigated before, but its applicability to the real-world practice of cardiac resuscitation has been unclear.5 Recently, Tom Aufderheide and colleagues6 at the Medical College of Wisconsin reported a study that makes a clear and compelling connection between delivery of positive-pressure ventilations at an excessive rate and increased intrathoracic pressure in patients with cardiac arrest. These investigators used a portable pressure-monitor to measure the airway pressure in each patient's endotracheal tube. This device enabled the researchers to electronically monitor the rate of positive-pressure ventilations during each resuscitation attempt, and correlated this value with the patient's airway pressure (a surrogate marker for intrathoracic pressure).

What Aufderheide and colleagues found was surprising. The highly experienced paramedics of Milwaukee's well-regarded Emergency Medical Services (EMS) were consistently ventilating victims of cardiac arrest at excessive rates. Rather than slowing to the American Heart Association's (AHA) recommended rate of 12 breaths a minute shortly after successful endotracheal intubation, most of the rescuers consistently hyperventilated their patient throughout the resuscitation attempt. In fact, maximum ventilatory rates of 30 or more a minute were the norm rather than the exception. No rescuer ventilated a patient at the recommended rate of 12 breaths a minute.

Interestingly, even after the investigators retrained EMS personnel to provide ventilations at a rate of 12 per minute, the rescuers were unable to achieve this goal. Participating paramedics slowed their ventilation tempo from 37 to 22 breaths a minute, but they prolonged the average duration of each positive-pressure breath to a proportionate degree. This compensation negated the benefit of rate reduction. In fact, both ventilatory patterns–rapid delivery of short-duration positive-pressure breaths and slower delivery of long-duration positive-pressure breaths–produced positive airway-pressure during roughly half of each resuscitation attempt.

Once the investigators established that excessive ventilation rates were a problem in the field, they returned to the laboratory to elucidate the significance of this phenomenon. To do so, they used a porcine model of cardiac arrest to explore the effect of hyperventilation on cardiac haemodynamics during cardiopulmonary resuscitation, and the likelihood of successful resuscitation. As expected, excessive ventilation rates (ie, 20 or 30 a minute) produced significantly higher mean intrathoracic pressures and lower coronary perfusion pressures than in animals that were ventilated at the AHA's recommended rate of 12 a minute. These differences were not only statistically significant, but clinically significant as well. Animals ventilated at 12 breaths a minute were much more likely to be successfully resuscitated (six of seven) than those who received 30 breaths a minute (one of seven). To assess whether these deleterious effects of hyperventilation were due to hypocapnoea or positive intrathoracic pressure, the researchers included a third group of seven pigs ventilated at 30 breaths a minute with 5% CO2. Such ventilation brought the animals' PCO2 to normal, but failed to improve intrathoracic pressure, coronary perfusion pressure, or the odds of successful resuscitation (one of seven). This last finding strongly suggests that the adverse effects of hyperventilation are due to increased intrathoracic pressure and decreased coronary perfusion, not hypocapnoea.

Because out-of-hospital cardiac arrest annually affects more than 200 000 US citizens and is associated with a nationwide mortality rate greater than 95%, even small improvements in resuscitation technique could yield big rewards.7 Over the past 20 years, the AHA's guidelines for cardiopulmonary resuscitation and advanced cardiac life-support have evolved in many ways, including an ever-increasing variety of airway adjuncts, numerous changes in treatment algorithms, and a growing list of drugs.8 Despite these changes, the overall rate of survival from out-of-hospital cardiac arrest nationwide remains poor.

Possibly, by focusing so much attention on discovering more effective drugs and more sophisticated defibrillator technology, we have lost sight of the vital importance of more mundane therapies, such as timely and proper provision of rescue breathing and chest compressions. Perhaps those who research cardiac arrest are guilty of the same oversight made by resuscitation team leaders–we have all been looking at the wrong aspects of the resuscitation attempt.

The findings of Aufderheide and colleagues are both intriguing and deeply disturbing. They are intriguing because they point out how seemingly innocuous alterations in cardiopulmonary resuscitation technique might have a detrimental impact on survival. They are disturbing because they suggest that inadvertent hyperventilation of patients in cardiac arrest might be more common, and more harmful, than previously realised. Since this was a small study, the findings require prompt confirmation. Both the field and laboratory aspects of the project appear to have been carefully designed and meticulously performed. However, the numbers of field observations and animals involved in the project were small. Independent corroboration by other EMS systems and laboratories will ensure that these findings are both valid and generalisable.

Meanwhile, what should we do? The researchers assert that ". . . Additional education of CPR providers is urgently needed to reduce these newly identified and deadly consequences of hyperventilation during CPR". Although some might argue that Aufderheide and colleagues are hyperventilating a bit themselves, nothing is risked (and much may be gained) by immediately urging everyone to rigorously follow the guidelines for cardiopulmonary resuscitation as they have existed for over two decades: "A is for airway, B is for breathing (at 12, not 30 times per minute), and C is for circulation."

Optimizing chest compression to rescue ventilation ratios during one-rescuer CPR by professionals and lay persons: children are not just little adults

C.F. Babbs, V.Nadkarni. Resuscitation 61 (2004) 173-181

Objective: To estimate the optimum ratio of chest compressions to ventilations for one-rescuer CPR that maximizes systemic oxygen delivery in children. Method: Equations describing oxygen delivery and blood flow during CPR as functions of the number of compressions and the number of ventilations delivered over time were adapted from the former work of Babbs and Kern. These equations were solved explicitly as a function of body weight, using scaling algorithms based upon principles of developmental anatomy and physiology. Results: The optimal compression to ventilation (C/V) ratios for infants and younger children increase sharply as a function of body weight. Optimal C/V ratios are lower for professional rescuers, who take less time to deliver a rescue breath, than for lay rescuers, who interrupt chest compressions for longer to perform ventilations. For professional rescuers the optimal C/V ratio, x*, is approximately where the W is the patient’s body weight in kg. For lay rescuers the optimum C/V ratio is approximately . These values can be approximated for children and teens by the following rules of thumb, based upon the age of the victim: "5 + one half the age in years" for professional rescuers and "5 + age in years" for lay rescuers. Conclusions: Compression to ventilation ratios in CPR should be smaller for children than for adults and gradually increase as a function of body weight. Optimal CPR in children requires relatively more ventilation than optimal CPR in adults. A universal compression/ventilation ratio of 50:2, targeted to optimize adult resuscitation, would not be appropriate for infants and young children.