El valor de las compresiones cardíacas durante el RCP
Desde que en 1960 Kouwenhoven, Jude y Knickerbocker propusieron en la revista JAMA los masajes cardíacos para mantener la circulación de los pacientes en paro cardíaco, ésto se ha adoptado en forma generalizada. Poco tiempo después la ventilación externa se sumó a las compresiones para dar soporte vital básico. Desde entonces hubo muy pocos cambios en la realización de RCP.
En los últimos años trabajos con animales (cerdos) han aportado algunos conceptos: A) la interrupción de las compresiones torácicas resulta en disminución de la perfusión coronaria durante la RCP y B) el aumento de la frecuencia de las ventilaciones con presión positiva disminuye la tasa de sobrevida (por la interrupción de las compresiones y por la disminución del retorno venoso provocado por el aumento de la presión intratorácica)
Estos datos hicieron hipotetizar que la realización de compresiones solas mejorarían la sobrevida de los pacientes con ataques cardíacos.
En 2 estudios recientemente publicados en NEJM (29 de Julio 2010 http://www.nejm.org/) se ha valorizado el papel de las compresiones cardíacas durante las maniobras de RCP por sobre las ventilaciones de rescate. Ambos estudios (uno sueco y otro multicéntrico USA/UK) demostraron que no hay diferencias en la sobrevida entre los pacientes que recibieron RCP Standard (con ventilaciones de rescate) y aquellos que recibieron sólo compresiones torácicas.
Compression-Only CPR or Standard CPR in Out-of-Hospital Cardiac Arrest
Leif Svensson, M.D., Ph.D., Katarina Bohm, R.N., Ph.D., Maaret Castrèn, M.D., Ph.D., Hans Pettersson, Ph.D., Lars Engerström, M.D., Johan Herlitz, M.D., Ph.D., and Mårten Rosenqvist, M.D., Ph.D.
Emergency medical dispatchers give instructions on how to perform cardiopulmonary
resuscitation (CPR) over the telephone to callers requesting help for a patient
with suspected cardiac arrest, before the arrival of emergency medical services (EMS)
personnel. A previous study indicated that instructions to perform CPR consisting
of only chest compression result in a treatment efficacy that is similar or even superior
to that associated with instructions given to perform standard CPR, which
consists of both compression and ventilation. That study, however, was not powered
to assess a possible difference in survival. The aim of this prospective, randomized
study was to evaluate the possible superiority of compression-only CPR over
standard CPR with respect to survival.
Patients with suspected, witnessed, out-of-hospital cardiac arrest were randomly assigned
to undergo either compression-only CPR or standard CPR. The primary end
point was 30-day survival.
Data for the primary analysis were collected from February 2005 through January
2009 for a total of 1276 patients. Of these, 620 patients had been assigned to receive
compression-only CPR and 656 patients had been assigned to receive standard CPR.
The rate of 30-day survival was similar in the two groups: 8.7% (54 of 620 patients)
in the group receiving compression-only CPR and 7.0% (46 of 656 patients) in the
group receiving standard CPR (absolute difference for compression-only vs. standard
CPR, 1.7 percentage points; 95% confidence interval, −1.2 to 4.6; P = 0.29).
This prospective, randomized study showed no significant difference with respect
to survival at 30 days between instructions given by an emergency medical dispatcher,
before the arrival of EMS personnel, for compression-only CPR and instructions
for standard CPR in patients with suspected, witnessed, out-of-hospital cardiac arrest.
(Funded by the Swedish Heart–Lung Foundation and others; Karolinska Clinical
Trial Registration number, CT20080012.)
CPR with Chest Compression Alone or with Rescue Breathing
Thomas D. Rea, M.D., Carol Fahrenbruch, M.S.P.H., Linda Culley, B.A., Rachael T. Donohoe, Ph.D., Cindy Hambly, E.M.T., Jennifer Innes, B.A., Megan Bloomingdale, E.M.T., Cleo Subido, Steven Romines, M.S.P.H., and Mickey S. Eisenberg, M.D., Ph.D.
The role of rescue breathing in cardiopulmonary resuscitation (CPR) performed by
a layperson is uncertain. We hypothesized that the dispatcher instructions to bystanders
to provide chest compression alone would result in improved survival as
compared with instructions to provide chest compression plus rescue breathing.
We conducted a multicenter, randomized trial of dispatcher instructions to bystanders
for performing CPR. The patients were persons 18 years of age or older with out-ofhospital
cardiac arrest for whom dispatchers initiated CPR instruction to bystanders.
Patients were randomly assigned to receive chest compression alone or chest compression
plus rescue breathing. The primary outcome was survival to hospital discharge.
Secondary outcomes included a favorable neurologic outcome at discharge.
Of the 1941 patients who met the inclusion criteria, 981 were randomly assigned to
receive chest compression alone and 960 to receive chest compression plus rescue
breathing. We observed no significant difference between the two groups in the
proportion of patients who survived to hospital discharge (12.5% with chest compression
alone and 11.0% with chest compression plus rescue breathing, P = 0.31)
or in the proportion who survived with a favorable neurologic outcome in the two
sites that assessed this secondary outcome (14.4% and 11.5%, respectively; P = 0.13).
Prespecified subgroup analyses showed a trend toward a higher proportion of patients
surviving to hospital discharge with chest compression alone as compared
with chest compression plus rescue breathing for patients with a cardiac cause of
arrest (15.5% vs. 12.3%, P = 0.09) and for those with shockable rhythms (31.9% vs.
25.7%, P = 0.09).
Dispatcher instruction consisting of chest compression alone did not increase the
survival rate overall, although there was a trend toward better outcomes in key clinical
subgroups. The results support a strategy for CPR performed by laypersons that
emphasizes chest compression and minimizes the role of rescue breathing. (Funded
in part by the Laerdal Foundation for Acute Medicine and the Medic One Foundation;
ClinicalTrials.gov number, NCT00219687.)