Accurate and continuous monitoring of critically ill patients is frequently achieved using invasive catheters, which is technically complex. Our purpose was to evaluate the validity and accuracy of a photoplethysmography (PPG)-based remote monitoring device compared to invasive methods of arterial line (AL) and Swan-Ganz (SG) catheters in a swine model of controlled hemorrhagic shock. Following a baseline phase, hemorrhagic shock was induced in 11 pigs by bleeding 35% of their blood volume, followed by a post-bleeding follow-up phase. Animals were monitored concomitantly by the PPG device, an AL and a SG catheter, for a median period of 447 min. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP, respectively), and cardiac output (CO) were recorded continuously. The complete data set consisted of 1312 paired observations. Correlations between the PPG-based technique and the invasive methods were significant (p < 0.001) during baseline, bleeding and follow-up phases for HR (r = 0.90–0.98), SBP (r = 0.90–0.94), DBP (r = 0.89–0.93), and CO (r = 0.76–0.90). Intraclass correlations for all phases combined were 0.96, 0.92, 0.93 and 0.87 for HR, SBP, DBP and CO, respectively. Correlations for changes in CO, SBP and DBP were significant (p < 0.001) and strong (r > 0.88), with concordance rates (determined by quadrant plots) of 86%, 66% and 68%, respectively. The novel PPG-based device was accurate and valid compared to existing invasive techniques and might be used for continuous monitoring in several clinical settings following further studies.