Basic arterial blood gas biomarkers as a predictor of mortality in tetralogy of Fallot patients

Abstract

Background:Serum lactate and base deficit have been shown to be a predictor of morbidity and mortality in critically ill patients. Poor preoperative oxygenation appears to be one of the significant factors that affects early mortality in tetralogy of Fallot (TOF). There is little published literature evaluating the utility of serum lactate, base excess (BE), and oxygen partial pressure (PO2) as simple, widely available, prognostic markers in patients undergoing surgical repair of TOF.Materials and Methods:This prospective, observational study was conducted in 150 TOF patients, undergoing elective intracardiac repair. PO2, BE, and lactate levels at three different time intervals were recorded. Arterial blood samples were collected after induction (T1), after cardiopulmonary bypass (T2), and 48 h (T3) after surgery in the Intensive Care Unit (ICU). To observe the changes in PO2, BE, and lactate levels over a period of time, repeated measures analysis was performed with Bonferroni method. The receiver operating characteristics (ROC) analysis was used to find area under curve (AUC) and cutoff values of various biomarkers for predicting mortality in ICU.Results:The patients who could not survive showed significant elevated lactate levels at baseline (T1) and postoperatively (T2) as compared to patients who survived after surgery (P < 0.001). However, in nonsurvivors, the BE value decreased significantly in the postoperative period in comparison to survivors (−2.8 ± 4.27 vs. 5.04 ± 2.06) (P < 0.001). In nonsurvivors, there was a significant fall of PO2 to a mean value of 59.86 ± 15.09 in ICU (T3), whereas those who survived had a PO2 of 125.86 ± 95.09 (P < 0.001). The ROC curve analysis showed that lactate levels (T3) have highest mortality predictive value (AUC: 96.9%) as compared to BE (AUC: 94.5%) and PO2 (AUC: 81.1%).Conclusion:Serum lactate and BE may be used as prognostic markers to predict mortality in patients undergoing TOF repair. The routine analysis of these simple, fast, widely available, and cost-effective biomarkers should be encouraged to predict prognosis of TOF patients.

Tetralogy of Fallot

“…2 The patient had an elevated lactate level on the previous labs, which is indicative of decreased oxygen perfusion to the tissues and is considered a marker for tissue hypoxia. 15 Taking this into consideration, adding to the list of differential diagnoses is a possible cardiac anomaly. The N-terminal pro b-type natriuretic peptide (NT-proBNP) test showed that it was signifi cantly elevated, which is associated with increasing right ventricular hypertrophy.…”

“…Patients with chronic hypoxemia compensate through erythropoiesis which is evidenced by increased hemoglobin and hematocrit levels such as those found in the patient's hematology workup 2. The patient had an elevated lactate level on the previous labs, which is indicative of decreased oxygen perfusion to the tissues and is considered a marker for tissue hypoxia 15. Taking this into consideration, adding to the list of differential diagnoses is a possible cardiac anomaly.…”