Background: Postoperative pulmonary complications in cardiac surgery increase mortality and morbidity. High flow nasal cannula oxygen therapy (HFNC) is one of the preventive measures to reduce the incidence of lung complications. HFNC can decrease dyspnea and improve physiologic parameters after extubation, including respiratory rate and heart rate, compared with conventional oxygen therapy. In this study, we evaluated the role of THRIVE (Transnasal Humidified Rapid Insufflation Ventilatory Exchange) after extubation. Methodology: We prospectively randomized 60 adults aged between 18 and 65 years undergoing elective cardiac surgery to either High flow oxygen therapy using THRIVE (Group A) or conventional nasal cannula (group B). Arterial paO2, paCO2, pH at three points of time i.e., 1, 2, 4 hrs after extubation were evaluated using arterial blood gas analysis. Ventilation duration, the incidence of reintubation, sedation score, mortality, and other complications were also assessed. Results: Thirty adults in each group had comparable patient characteristics. There was a statistically significant decline in paCO2 in group A at 1, 2, 4 hrs post extubation (P = 0.022, 0.02, <0.001) with a significant increase in oxygenation (P < 0.001) when compared to group B.ICU stay duration was similar between two groups. No complications were noted in both groups. Conclusion: THRIVE is safe to use following extubation in adult cardiac surgical patients.