A novel technique to measure position-dependent resistance changes in the vertebral arteries postmortem: new insights into the aetiology of SIDS?
OBJECTIVE
A central respiratory regulation disturbance--triggered by impaired oxygen supply to the brainstem--is being discussed as an aetiological factor in sudden infant death syndrome. In this experimental study, further insight was sought into how far cervical spine movements may induce critical narrowing of the vertebral arteries.


METHODS
In 10 infant bodies, the vertebral arteries were cannulated close to their origin and perfused with a fluid bolus of 5 ml in 2 s. The intravascular peak pressure created was memorized. Individual resistance indices were computed for every vertebral artery by relating the average pressure maximum from 10 measurements each with maximal rotation of the neck to either side alone and then with additional hyperextension of the cervical spine to the average peak pressure in neutral head position.


RESULTS
Alterations of position-induced pressure changes occurred in the vertebral arteries of all children. Considering exclusively the combined movements of rotation plus extension, resistance increased ipsi- and contralaterally--no matter which side the head was turned--in three infants. A further three reacted with resistance surges only contralateral to the direction of rotation, and one only ipsilateral. Double contralateral associated with only one-directional ipsilateral rise was observed twice, and vice versa once.


CONCLUSIONS
The presented method enables crude quantification of postmortem dynamic resistance alterations in the vertebral arteries. How far such measurements reflect authentic circulatory conditions during life remains to be assessed.
Wald
M
M
Division of Neonatology and Intensive Care, Department of Paediatrics, University of Vienna, Austria. martin.wald@meduniwien.ac.at
Klupp
N
N
Lawrenz
K
K
Puig
S
S
Heimberger
K
K
Reiter
C
C
Pollak
A
A
Ipsiroglu
O
O
D001344:Autopsy / Q000379:methods*; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D019416:Head Movements / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011187:Posture / Q000502:physiology*; D013398:Sudden Infant Death / Q000209:etiology; D014655:Vascular Resistance / Q000502:physiology*; D014711:Vertebral Artery / Q000503:physiopathology*