Augmented cardiovascular responses to episodes of repetitive compared with isolated respiratory events in preschool children with sleep-disordered breathing.
BACKGROUND
Childhood sleep disordered breathing (SDB) presents as isolated respiratory events or episodes of consecutive repetitive events. We hypothesized that the surge in blood pressure (BP) and heart rate (HR) would be greater at the termination of events during episodes of repetitive events than following isolated events.


METHODS
% change in HR and pulse transit time (PTT; inverse surrogate of BP) were calculated from the last half of an event to: (i) between successive repetitive events; (ii) termination of the last repetitive event; (iii) event termination for isolated events.


RESULTS
69% of the children exhibiting both isolated and repetitive events had more repetitive than isolated events. %HR change between repetitive events (27 ± 1%) was greater than at event termination for isolated events (17 ± 1%; P < 0.001). %PTT change at the termination of the last repetitive event (-8 ± 2%) was greater than at the termination of isolated events (-2 ± 2%; P < 0.05).


CONCLUSIONS
Episodes of repetitive respiratory events evoke a greater acute cardiovascular response, including surges in BP and HR between events, than do isolated events. Given that the majority of respiratory events in preschool children occur as repetitive episodes, this finding should be taken into account when assessing the impact of respiratory events for a given child.
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.|Department of Paediatrics, Monash University, Melbourne, Australia.
Lisa M
LM
Walter
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.|Department of Paediatrics, Monash University, Melbourne, Australia.
Sarah N
SN
Biggs
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
Lauren C
LC
Nisbet
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
Aidan J
AJ
Weichard
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.
Milou
M
Muntinga
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.|Department of Paediatrics, Monash University, Melbourne, Australia.|Melbourne Children's Sleep Centre, Monash Children's Hospital, Melbourne, Australia.
Margot J
MJ
Davey
Clinical Sciences Research, Murdoch Children's Research Institute, Melbourne, Australia.
Vicki
V
Anderson
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.|Department of Paediatrics, Monash University, Melbourne, Australia.|Melbourne Children's Sleep Centre, Monash Children's Hospital, Melbourne, Australia.
Gillian M
GM
Nixon
The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia.|Department of Paediatrics, Monash University, Melbourne, Australia.
Rosemary S C
RS
Horne
D000367:Age Factors; D001794:Blood Pressure; D002319:Cardiovascular System / Q000503:physiopathology*; D002675:Child, Preschool; D005260:Female; D006339:Heart Rate; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D011379:Prognosis; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000503:physiopathology*; D013997:Time Factors