Browsing by Author "Schoeman, Doreen"

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    Lactate concentration and oxygen flux post cardiopulmonary bypass: a pilot study
    (2020-06) Schoeman, Doreen; Smit, Marli; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Anesthesiology and Critical Care.
    ENGLISH ABSTRACT: Objective: To identify the incidence and the main contributing factor of postoperative hyperlactataemia following cardiopulmonary bypass surgery. Design: Single-centre, prospective, non-randomized, observational pilot study. Setting: Tertiary hospital, University setting. Participants: Twenty-six patients who all underwent cardiopulmonary bypass for elective cardiac surgery and who met the inclusion criteria. We excluded patients with pre-existing conditions or medications that could possibly alter lactate metabolism or contribute to aerobic increase in lactate production. Interventions: Observational. Measurements: Arterial lactate, mixed venous oxygen saturations (SvO2), haemoglobin, arterial saturation, and mixed venous partial pressure (PvO2) were measured. Delivery of oxygen (DO2) and oxygen consumption (V𝑂𝑂̇2) were calculated for the first twelve postoperative hours. Factors potentially influencing V𝑂𝑂̇ 2 (temperature, shivering, pain, anxiety, the use of inotropic support, and the presence or absence of ventilation) were also documented. Main results: Transient hyperlactataemia (that peaked between postoperative hours two to eight) occurred in 47% of cases following cardiopulmonary bypass. Postoperative hyperlactataemia occurred as a result of an increase in oxygen consumption (V𝑂𝑂̇ 2). The use of adrenaline and an increase in temperature (as a result of passive rewarming) were identified as the contributing factors responsible for this V 𝑂𝑂̇ 2 increase. Postoperative delivery of oxygen (DO2) remained adequate; as illustrated by normal to high cardiac output, haematocrit, and arterial saturations.