title: Using physiology to guide time to cord clamping.
abstract: Immediate clamping and cutting of the umbilical cord at birth has been the accepted standard of care for decades. The physiologic rationale relating umbilical cord clamping (UCC) to the events of the circulatory transition is not considered in arbitrarily recommended cord clamping times. Systematic review of early versus deferred UCC shows significant hemodynamic benefits to the deferred group. Mechanisms for this protective effect are considered in this review. The original concept of a placental transfusion with a volume load and prevention of low cardiac output relies on the physiological end point of the amount of blood transfused. The newer concept of an ordered physiological transition is increasingly supported. This model places aeration of the lungs and an increase in pulmonary blood flow back at the centre of the circulatory transition with timing of UCC being related to establishment of respiration. The need for "physiologically based" UCC is discussed.
authors.affiliation: University of Sydney and Royal North Shore Hospital, Sydney, Australia. Electronic address: martin.kluckow@sydney.edu.au.
authors.forename: Martin
authors.initials: M
authors.lastname: Kluckow
authors.affiliation: The Ritchie Centre, MIMR-PHI Institute for Medical Research, Monash University, Melbourne, Australia.
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Hooper
mesh_terms: D001049:Apnea / Q000503:physiopathology / Q000628:therapy; D003250:Constriction; D036861:Delivery, Obstetric; D005260:Female; D005333:Fetus / Q000098:blood supply* / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology; D007232:Infant, Newborn, Diseases / Q000503:physiopathology / Q000628:therapy; D007234:Infant, Premature / Q000502:physiology; D008168:Lung / Q000098:blood supply / Q000502:physiology*; D011247:Pregnancy; D012123:Pulmonary Ventilation / Q000502:physiology; D013997:Time Factors; D014470:Umbilical Cord / Q000098:blood supply / Q000502:physiology / Q000601:surgery*
keywords: Circulatory transition; Hemodynamics; Superior vena cava flow; Umbilical cord clamping