A manometer integrated into a manual resuscitator includes a housing with a communication path, and a pressure gauge integrally forming part of the housing. A sensing chamber and an atmospheric chamber are separated by a diaphragm subject to distortion by differential pressure between the chambers, with a spring to restore the diaphragm upon equalization of the pressures. A shaft journaled in a first bearing on the diaphragm and a second bearing in one of the chambers rotates in the bearings upon diaphragm distortion, and an indicator on the shaft indicates differences in pressure between the chambers.