In this study, features were extracted from PPG waveforms and used to train different classifier models, where cardiac output (CO) was classified into three ranges: low, healthy, and high. We used a curated dataset from the PhysioNet platform, Medical Information Mart for Intensive Care III (MIMIC-III) Matched database, which contains PPG waveforms and CO measurements. Specifically, there were 16 viable patients with over 184 hours of synchronous PPG and CO measurements. The data was then categorized into three distinct classes: Low CO (< 5 L/min), Healthy CO (5-6 L/min), and High CO (> 6 L/min). MATLAB's Classification Learner application was used to implement and compare different classification techniques where thirty pre-configured models were compared, including SVMs, KNNs, Ensemble, Linear and Logistical Regression, and Neural Networks. From all the tested models, a Bagged Trees Ensemble model was determined to have the highest validation and testing accuracy (87.7% and 88.2%, respectively). It is noteworthy that, with our approach, there was no calibration needed and since the validation and testing accuracies were similar, this suggests that the selected model did not overfit the data.