By systematically comparing the response times of the five parameters under the four types of hypoxia, we concluded that the order in which the monitored parameters respond is affected by the type (cause) of hypoxia. Notably, among the five parameters studied, NADH is not always the first parameter to respond. As such, multiparametric monitoring may be required to increase the sensitivity of hypoxia detection. Any parameter that responded earlier than the NADH merits attention. As indicated in Fig. 3, the lag time between the NADH response and the directly affected parameters, such as respiration in hypoxic hypoxia, CBF in circulatory hypoxia, and respiration, ECG, and CBF in histogenous hypoxia, is only between 2.2 and 8.9 s. In contrast, the lead time between the NADH response and the indirectly affected systemic parameters, such as ECG in hypoxic hypoxia, respiration, ECG in hypemic hypoxia, and respiration and ECG in circulatory hypoxia, is between 6.2 and 55.6 s. The results suggest that among the five parameters studied, NADH is the parameter that is most sensitive to hypoxia. This implication excludes the directly affected parameters caused by different types of hypoxia.