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Figure 4. The transition of radial mABP, rectal temperature, and tympanic temperature. mABP: Mean arterial blood pressure.
Figure 5. The radial mABP wave after setting PF flow. mABP: Mean arterial blood pressure.
the dissection flap, or atheroembolic events [ 7 ]. Alternatively, ascending aortic cannulation, including echocardiographyguided techniques or a combination of right axillary and femoral artery cannulation, has demonstrated improved safety profiles and favorable postoperative outcomes [ 8, 9 ].
In this complex case of TAAD with lower limb malperfusion, CPB was established via right femoral cannulation. During the initial phase of CPB, no significant differences were observed in mABP or TOI change rates. However, TOI and DO 2 Hb in the left lower limb gradually improved following CPB initiation. Approximately 15 min into CPB, 15 mmHg of a marked bilateral discrepancy in mABP between the radial arteries became evident, coinciding with declining cerebral TOI and DHbO 2. To address malperfusion, we transitioned from NPF to PF, resulting in a gradual improvement in cerebral TOI.
The efficacy of PF in mitigating cerebral malperfusion in TAAD cases remains uncertain, with limited data available. Current CPB guidelines suggest that PF may reduce postoperative pulmonary and renal complications and recommend its use for patients at high risk of adverse outcomes( Class IIa, Level of Evidence B) [ 10--12 ]. Although its impact on cerebral outcomes is less established, studies such as O’ Neil et al. have demonstrated that microcirculatory perfusion is better preserved with PF compared to NPF during CPB [ 13 ]. Nevertheless, the
broader question of whether PF offers definitive advantages over NPF during CPB remains unresolved [ 14, 15 ].
One study indicated that patients with significant cerebrovascular stenotic lesions( 75 % stenosis or multiple prior cerebral infarctions) undergoing aortic surgery experienced fewer cerebrovascular accidents with PF compared to NPF over a 54-month follow-up period. In contrast, Murkin et al. reported no significant difference in cerebrovascular accident rates between PF and NPF in a similar cohort [ 16, 17 ]. _ Ipek et al. observed no differences in neurocognitive outcomes but noted potential cerebral perfusion benefits of PF based on S100b protein levels and near-infrared spectroscopy( NIRS) values [ 18 ]. Reductions in regional cerebral oxygen saturation( rSO 2) from baseline are associated with increased risks of postoperative cognitive dysfunction( POCD), delirium, and prolonged intensive care unit stays [ 19--21 ].
In our case, the lowest cerebral TOI values reached 85 %( left) and 67 %( right), with TOI reductions from the baseline of approximately 10 %. Interventional thresholds for NIRS changes typically include 10--20 % reductions from baseline or absolute values below 50 % [ 22--24 ]. Following the switch to PF, cerebral TOI improved( left cerebral TOI: from 85 to 97 %, Right cerebral TOI: from 67 to 77), and the decline in DO 2 Hb stabilized, likely due to enhanced oxygen transport