M. Bagherinasab and N. H. Darban: J Extra Corpor Technol 2025, 57, 160--163 161
Table 1. Creatinine variations.
Parameter |
Base |
After surgery |
12 h after surgery |
24 h after surgery |
48 h after surgery |
72 h after surgery |
Creatinine( mg / dL) |
4.8 |
4.8 |
4.6 |
4.6 |
3.8 |
2.6 |
Table 2. Lactate level fluctuations.
Variable |
Base |
30 min after CPB initiation |
Lactate level |
|
|
( mmol / L) |
|
|
60 min after CPB initiation
90 min after CPB initiation
120 min after CPB initiation
ICU admission
6 h after CPB weaning
12 h after CPB weaning
24 h after CPB weaning
2.4 2 1.8 2 1.4 2.1 1.4 1.2 0.9
comprised a combination of one-part oxygenated blood mixed with four parts of the DN crystalloid solution. The administration of a half-main dose of DN cardioplegia was repeated at intervals of every 90 min.
PF was established after aortic cross clamp and cardioplegia injection, characterized by a base flow of 30 %, a width of 60 %, and a frequency adjusted to 70 beats per minute. Quality of the pulsatile flow was assessed using Energy Equivalent Pressure( EEP). Modifications to the width and frequency settings were implemented to ensure that the EEP exceeded the Mean Arterial Pressure( MAP) by 15 % [ 4 ]. Furthermore, it is important to note that in the recent quantification of pulsatile flow, the EEP is utilized to evaluate the quality of pulsatile flow by calculating the pressure beneath the arterial pressure and the CPB flow curve during the pulsatile cycle. In this context, it is essential to maintain the EEP value at 10--15 mmHg above the MAP [ 4 ].
Throughout the course of CPB, a specific strategy was employed to ensure that hemoglobin concentrations remained above 8 g / dL. This approach included the transfusion of three units of PRBC in conjunction with a three-liter hemofiltration process. In this case, the patient encountered volume overload due to renal failure, dysfunction of the aortic valve, and a diminished EF. As a result, there was a considerable need for improved hemoconcentration to effectively manage these complications. In instances of hypotension, we elevated the flow rate to 6 L / min / m 2, corresponding to a PI of 3 L / min / m 2. However, if the hypotension persisted with a MAP below 60 mmHg, we administered norepinephrine as a bolus dose of 20 lg / cm ³. Throughout the course of cardiopulmonary bypass, a total of 10 mg of norepinephrine was utilized.
The average DO 2 i ranged from 280 to 300 mL / min / m 2. The calculation of DO 2 i was performed using the following formula: DO 2 i( mL / min / m 2)= pumpflow( L / min) [ Hct / 2.94( g / dL) 1.36 arterial oxygen saturation(%) + partial pressure of arterial oxygen( mm Hg) 0.003 ] 10 / BSA( m 2). The B-Capta online blood gas monitoring system developed by LivaNova was employed, facilitating precise measurements of partial pressure of oxygen( pO 2) and temperature within the arterial line, as well as saturation, hematocrit( HCT), hemoglobin( Hb), and temperature in the venous line. The calculation of DO 2 i was performed manually at 15-minute intervals, utilizing the specified formula.
Following an aortic clamp duration of 112 min and a CPB period of 130 min, the patient was successfully weaned from the heart-lung machine( HLM) without the need for any mechanical assistance or pharmacological support.
An outstanding feature of this case was the enhancement of the EF to 45 %, which ultimately removed the requirement for hemodialysis after the surgery, as well as a reduction in lactate levels after CPB when compared to pre-operative measurements. The fluctuations in creatinine and lactate levels are depicted in Tables 1 and 2.
Comment
The limitations related to lactate as a robust predictive marker are grounded in the understanding that hyperlactatemia may arise from a combination of factors occurring both during and after surgery [ 5 ]. The association between diminished flow rates( below 100 mL / kg / min) and DO 2 i during CPB, in conjunction with the duration of CPB and circulatory arrest, HCT levels, temperature variations during and post-CPB, as well as systemic inflammatory responses, has been shown to have a significant correlation with both intraoperative and postoperative lactate concentrations [ 6, 7 ].
The capacity of DO 2 i to accurately forecast sufficient organ perfusion, especially within the renal system, has been evidenced by a considerable sample size, with a specific DO 2 i threshold established at 270 mL / min / m 2 [ 8 ]. In this case, we maintained the DO 2 i level above 280 mL / min / m 2.
Within the context of this patient case, we implemented PF to enhance organ perfusion following an increase in PI. Endorgan dysfunction and the duration of recovery following cardiac surgery are influenced by both non-CPB and CPB-related factors. Among the CPB-related factors, the activation of inflammatory and coagulation pathways resulting from blood exposure to synthetic materials, the absence of natural pulsatile flow, ischemic damage, embolic events, and hypothermia are significant contributors. Notably, the absence of physiological pulsation associated with non-pulsatile CPB is regarded as a critical factor leading to end-organ dysfunction and an extended recovery period post-surgery [ 9--11 ]. The conceptual benefits of pulsatile CPB over its non-pulsatile counterpart primarily arise from its capacity to mimic the body’ s inherent hemodynamic environment. This mimicry produces more physiologically pertinent pulsatile waveforms, thereby promoting improved mechanical energy transfer to the vascular endothelium