Where NIH = normalized index of hemolysis in grams of hemoglobin released into the blood per 100 L of flow through the circuit (g/100 L); ΔpfHb = increase in pfHb over the sampling time interval (g/L); V = circuit volume (L); HCT = hematocrit ; Δt = sampling time interval (min); Q = average blood flow rate (L/min).
Post treatment, the circuit volume is either not reinfused (BW <25 kg) or reinfused using isotonic saline (BW >25 kg), with a volume depending on the hydration status and the originally infused volume of PC.
The following GasMan® program settings were kept constant for all simulations (unless stated differently): a 70 kg patient, an anesthesia breathing circuit volume of 8 L, a FGF of 1 L.min-1, an alveolar minute ventilation (VA) of 5 L.min-1, a functional residual capacity (FRC) of 2.5 L, and a cardiac output (Q) of 5 L.min-1.
Many of the factors that speed induction also hasten washout time: elimination of rebreathing, high fresh gas flow, low anesthetic-circuit volume, low absorption by the anesthetic circuit, decreased solubility, high cerebral blood flow, and increased ventilation.
The volume of PC needed is calculated based on the circuit priming volume and the maximum allowed extracorporeal blood volume of the child (= 8 ml/kg × BW).
Aspiration volume was 5 to 10 ml lower than Circuit Flushing volume.
The most common mechanisms by which ECMO affects pharmacokinetics are sequestration in the circuit, increased volume of distribution, and decreased drug elimination.
The pigs weighed 49.7 ± 2.3 kg, preparation took 119 ± 29 min and cardiac MRI scan time was 63 ± 15 min. Prior to induction of cardiac arrest activated clotting time was 349 ± 83 s, and ECMO circuit priming volume was 538 ± 17 ml.
Circuit compression volume is that part of VT set on the ventilator that remains within the ventilator and inspiratory circuit, and does not reach the airways of the patient.
Although the circuit priming volume is proportionally larger in children of lower weight, we did not find any relation between the frequency of hypotension and age, weight, or surface area of the filters.
