Ex vivo evaluation of a new neonatal/infant oxygenator: comparison of the Terumo CAPIOX® Baby RX with Dideco Lilliput 1 and Polystan Safe Micro in the piglet model

Objective: A newly developed neonatal and infant oxygenator with a nonheparin biocompatible polymer coating, low priming volume (43 mL), high oxygen transfer, wide operating range (<1.5 L/min) and low pressure drop represents a promising solution for cardiac surgery in neonates and infants. We compared the new CAPIOX® Baby RX, Terumo (BRX) with two commonly used neonatal oxygenators: Dideco Lilliput 1 (DL1) and Polystan Safe Micro (PSM) in a piglet model.

Methods: Fifteen piglets (5.6±1.3 kg) were placed on standardized cardiopulmonary bypass (CPB) for 6 hours using one of the three oxygenators ( n = 5 in each group). After 120 min, the system was cooled to 25°C for 60 min and then returned to normothermia. Arterial and venous blood gas data and temperature were recorded continuously by a CDI500 System (Terumo). Pressure drop, FiO2 and gas flow were recorded. Blood samples were taken before CBP, after 10 min, before and after cooling, and at the end. Total blood counts, thrombin-antithrombin complex and plasma-free haemoglobin (PfHb) were measured.

Results: All oxygenators showed acceptable performance for the duration of CPB. The BRX had lower mean gas flow (0.33±0.05 L/min) and FiO2 (0.43± 0.02%) throughout CPB than the DL1 (1.14±0.25 L/min, p = 0.006 and 0.60±0.02%, p = 0.009, respectively) or the PSM (1.47±0.87 L/min and 0.54±0.08%, p = ns). Pressure drop in the BRX group ranged from 12 to 22 mmHg. This was significantly lower than in the DL1 group (39-65 mmHg, p = 0.005). In the PSM group, values ranged between 24 and 33 mmHg (p = ns). The increase in PfHb at six hours was significantly lower in the BRX (11.3±4.2 ng/dL) versus the DL1 (42.2±6.1 ng/dL, p = 0.004) and the PSM (56.7±15.5 ng/dL, p = 0.045).

Conclusions: The BRX is as safe as the DL1 and the PSM, with superior performance in pressure drop, efficient blood gas management and lower haemolysis. The BRX exhibited the lowest prime, hold-up volume and breakthrough time.

Release of cardiac troponin I in antegrade crystalloid versus cold blood cardioplegia

OBJECTIVE

The purpose of this study was to assess the efficacy of myocardial protection, comparing antegrade crystalloid cardioplegia with cold blood cardioplegia, in patients with preserved left ventricular function who were undergoing elective first coronary artery bypass grafting. Release of cardiac troponin I was used as a marker for the effectiveness of myocardial protection.

METHODS

A consecutive series of 62 patients were randomly assigned to receive crystalloid or blood cardioplegia. Cardiac troponin I concentrations were determined in venous blood samples before the operation, immediately after unclamping, at 6, 9, 12, and 24 hours, and daily thereafter for 5 days.

RESULTS

Rising levels of troponin I were found in all patients. The time course and peak release were similar in the crystalloid cardioplegia and the blood cardioplegia groups. No patients in either group had electrocardiographic evidence of perioperative myocardial infarction. Cardiac troponin I was able to detect small areas of myocardial damage, not revealed by electrocardiography or creatine kinase MB release. Aprotinin administration was associated with lower cardiac troponin I release in both groups. Cardiac troponin I was lower in patients whose conditions did not require electrical defibrillation after aortic unclamping, irrespective of cardioplegia type. The presence of a main stem lesion was associated with higher cardiac troponin I release only in the crystalloid cardioplegia group.

CONCLUSIONS

Antegrade cold blood cardioplegia is equally effective as antegrade crystalloid cardioplegia in a randomized group of patients with preserved left ventricular function who were undergoing elective first coronary artery bypass grafting. Aprotinin administration resulted in lower cardiac troponin I release, whereas electrical defibrillation was related to a higher release irrespective of cardioplegia type. The presence of a main stem lesion resulted in higher cardiac troponin I release in the crystalloid cardioplegia group.