A pulse oximeter includes a housing defined by at least a first housing portion and a second housing portion wherein the second portion includes a passage. A sensor module disposed in the housing and proximate the passage includes at least one light emitting diode and at least one photodetector. A processing module also disposed in the housing and configured to communicate with the sensor module includes at least a processor, a network interface, and a power supply. The pulse oximeter further includes a pad having at least a bottom surface and a pad passage, as well as an adhesive configured to be disposed on at least a portion of the bottom surface of the pad. The housing is configured to releasably engage the pad wherein the housing passage and the pad passage are substantially aligned with one another.