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ABSTRACT ABSTRACT: The maturation of the process of spontaneous recovery from hypoxic apnea by gasping (autoresuscitation) was characterized in adult, weanling (18-22 d), and infant (5 and
10 d) BALB/c mice. ECG and respiration were recorded and hypoxic apnea was induced with 97% N2-3% CO2. Administration of 21% O2 at onset of hypoxic apnea resulted in successful
autoresuscitation in all 63 animals tested. In all mice, three sequential stages occurred: _1_) gasping with marked bradycardia, _2_) rapid increase in heart rate (cardiac resuscitation),
and _3_) increase in respiratory rate (respiratory resuscitation). Despite these similar stages, marked maturational differences were apparent. The times to cardiac and respiratory
resuscitation were longer in the pups than in the older mice, whereas the gasp frequency before cardiac resuscitation was lower in the infants. Resuscitation time correlated with gasp
interval (1/gasp frequency). In addition, the initial bradycardia at onset of gasping was more pronounced in the pups. A 30- or 60-s delay in oxygen administration after onset of hypoxic
apnea caused a marked decrease in the adults' ability to autoresuscitate, without affecting that of the pups. A comparison of gasp frequency in 21% O2 _versus_ 97% N2-3% CO2 showed that
the presence of oxygen increased gasp frequency in the pups, but had no effect on gasp frequency in the weanlings or adults. We conclude that autoresuscitation is equally effective in both
infant and adult BALB/c mice but only when oxygen is available before the onset of hypoxic gasping. Accordingly, the adult's ability to autoresuscitate rapidly can be viewed as an
adaptation required by a limited tolerance for prolonged hypoxia. In contrast, it appears that the infant mouse's greater tolerance of hypoxia allows a slower autoresuscitation with a
lower heart rate and gasp frequency. This conserves energy, thus facilitating prolonged survival and enabling recovery when O2 availability is delayed. SIMILAR CONTENT BEING VIEWED BY OTHERS
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INFORMATION AUTHORS AND AFFILIATIONS * The Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, 63110, Missouri William M Gershan, Margaret S
Jacobi & Bradley T Thach Authors * William M Gershan View author publications You can also search for this author inPubMed Google Scholar * Margaret S Jacobi View author publications You
can also search for this author inPubMed Google Scholar * Bradley T Thach View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS
Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Gershan, W., Jacobi, M. & Thach, B. Maturation of Cardiorespiratory Interactions in Spontaneous Recovery from Hypoxic Apnea
(Autoresuscitation). _Pediatr Res_ 28, 87–93 (1990). https://doi.org/10.1203/00006450-199008000-00003 Download citation * Received: 11 January 1990 * Accepted: 02 April 1990 * Issue Date: 01
August 1990 * DOI: https://doi.org/10.1203/00006450-199008000-00003 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry,
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