Abstract: A multi-function portable patient monitor arrangement having minimal power requirements particularly useful in association with patient transport apparatus to monitor patient functions such as, monitor means to monitor rate of patient heartbeat, body temperature monitor means to detect patient body temperature and patient environment oxygen monitor means to monitor inspired oxygen concentrations in the patient environment, including a direct current voltage at positive source voltage V1 supplied to first voltage reduction means where a positive voltage V2 is supplied at an output from the first voltage reduction means to patient heartbeat monitor means, patient body temperature monitor means, to patient environment oxygen monitor means and to second voltage regulator means where the second voltage regulation means provides output at negative voltage V3 relative to V2 to provide power to the patient body temperature sensor means environmental oxygen monitor means and the heartbeat monitor means.