The Cardiopulmonary Response to OKT3 in Orthotopic Cardiac Transplant Recipients: Discussion

29 Oct
2014

Figure 2 illustrates the changes in Sa02 and related variables, including CVP, mean pulmonary arterial pressure, pulmonary arterial occlusion pressure, and PVRI.
Relative hypoxemia occurred during the fifth through seventh hours after the dose, as reflected by a decrease in the PaOjj/FlOa ratio. This decrease in PaOz was readily compensated for by an increase in supplemental FIo2, required in 18 of the 23 patients. Simultaneous with this diminished Sa02 was a fall in calculated PVRI (from level of 277.1 dynes’s^cm^/m2 before the dose to 166.0 dynes#s*cm~/m2), as a consequence of a drop in mean pulmonary arterial pressure.

There was a statistically significant increase in mean weight (± SE) following transplantation, averaging 2.4 kg (from preoperative weight of 71.0 ±2.6 kg to 73.4 ±2.7 kg after surgery; p<0.05). further
All patients randomized to OKT3 were retained in the ICU for an additional 24-hour period encompassing their first two doses of OKT3. All were exposed to continued aggressive hemodynamic monitoring during this period. None of the patients experienced similar cardiopulmonary changes during their second or subsequent doses of OKT3. During this period, none required reintubation or suffered any discernible longterm sequelae from the changes described previously.
Discussion
Administration of the first dose of the new monoclonal antibody, OKT3, in this group of recipients of orthotopic cardiac transplants resulted in clinically apparent alterations in cardiopulmonary function. Although not a uniform response, this perturbation could be generally characterized in two phases. Early after the first dose, typically within the first hour, the now febrile patients exhibited a hyperdynamic, hypertensive, and tachycardiac phase.
Despite the increase in cardiac output and oxygen delivery (arterial saturation and hemoglobin concentration were stable), there was an increase in extraction ratio and oxygen consumption, associated with a fall in Sv02.

Figure 2. Change in pulmonary and related parameters over time. Arrow indicates OKT3 dose; asterisk indicates p<0.05 vs level before dose.

Figure 2. Change in pulmonary and related parameters over time. Arrow indicates OKT3 dose; asterisk indicates p<0.05 vs level before dose.

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