La nouvelle adresse de la liste est: [EMAIL PROTECTED]
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C'est vrai que selon les études on a tous tendance a hyperventiler
les Pts intuber.
Encore plus en situation de réanimation initiales
Et encore plus en milieu préhosp
... la prémisse étant qu'ils sont acidotique de toute façon et cela
ne peut pas nuire ! ?
Ça l'air qu'on s'est encore gouré ! ?
Charles Brault
Apr 5, 2004
Hyperventilation during CPR may be deadly
Dallas, TX - A new study has identified a tendency by emergency
medical
services (EMS) personnel to hyperventilate patients during
cardiopulmonary
resuscitation (CPR) of out-of-hospital cardiac arrest. A follow-up
animal
study showed ventilation rates similar to those used in the field
resulted
in increased intrathoracic pressures, decreased coronary perfusion
pressures, and reduced survival.
The report appears online as a rapid access publication, and will be
published in the April 27, 2004 issue of
Circulation.[<_JavaScript:popCitation('#bibref1')>1]
"Oxygenating the patient has always been a fundamental mainstay of
resuscitative efforts, and until now, there has been no known
detrimental
effect," of hyperventilation, lead author Dr Tom P Aufderheide
(Medical
College of Wisconsin, Milwaukee) told heartwire. The overall survival
rate
from cardiac arrest in the United States is only about 5%, he said.
"Excessive ventilation may be contributing to that poor outcome."
Coauthor of the study was Dr Keith G Lurie (University of Minnesota,
Minneapolis).
The threat of positive pressure
The new observation was an incidental finding during the process of a
completely different study, Aufederheide said. Researchers were
accompanying rescuers on calls, measuring the number and duration of
ventilations given. After seven patients, they noticed that the mean
ventilation rate was about 37 breaths per minute, much higher than
the 12
to 15 breaths per minute recommended by current American Heart
Association
guidelines for patients with a secured airway during CPR.
Training was then offered to the EMS personnel stressing the need for
a
lower ventilation rate, the authors note. In the subsequent six
patients,
ventilations fell to about 22 breaths per minute. However,
ventilations
were also a slightly longer duration after training, about 1.18
seconds per
breath compared with 0.85 seconds prior to training, meaning that the
percentage of time that a positive pressure was recorded in the lungs
was
still about 47%. No patient in this small sample survived.
During the decompression phase in CPR, the researchers explain, a
vacuum is
created within the chest, drawing venous blood back to the heart.
Frequent
ventilations mean that less blood returns to the right heart between
compressions, potentially reducing the effectiveness of CPR.
To look at the consequences of excessive ventilation on outcomes,
they went
on to study a cardiac arrest model in pigs, attempting to replicate
the
effects of the same rates of hyperventilation seen in the patients.
Pigs
ventilated at higher rates had lower survival, as well as
significantly
increased mean intrathoracic and decreased coronary perfusion
pressures.
Survival in an animal model of CPR by ventilation rate (breaths per
minute)
"Additional education of CPR providers is urgently needed to reduce
these
newly identified and deadly consequences of hyperventilation during
CPR,"
the researchers conclude. "Any individual who performs CPR as a part
of
their professional practice should monitor ventilation rates during
cardiac
arrest, and limit them to 12 breaths per minute," Aufderheide said.
"This is the first paper of its kind documenting the potentially
detrimental effects of hyperventilation, and will really be valuable
in
targeting further research," Dr Mary Fran Hazinski (PhD, Vanderbilt
University Medical Center, Nashville, American Heart Association
Emergency
Cardiac Care Program) told heartwire.
Sources
782ed1.jpg
1. Aufderheide TP, Sigurdsson G, Pirrallo RG, et al.
Hyperventilation-induced hypotension during cardiopulmonary
resuscitation.
Circulation 2004; 109:DOI: 10.1161/01.CIR.0000126594.79136.61.
782ed1.jpg
782ed1.jpg
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