Abstract: Vital sign monitoring is especially challenging in small animals, given the high metabolic rates and small volumes under consideration. An embodiment of the present invention includes a unique nose-cone design and associated instrumentation which allows for measurement of respiratory parameters, including anesthesia gas concentration, inspiratory and expiratory O2, and inspiratory and expiratory CO2 (capnometry). Such instrumentation facilitates a physiologic assessment of small animals undergoing general anesthesia, an increasingly important consideration as small animals play a greater role in in vivo biomedical studies. In addition, the techniques proposed herein are suitable for measurement on small respiratory volumes associated with neonatal monitoring.