A catheter manometer is a device that measures pressure within a body cavity or blood vessel by connecting a pressure-sensitive catheter to a calibrated manometer. It is essential in clinical practice for accurately assessing intracardiac, intravascular, or intracranial pressures, guiding diagnosis and management of conditions like heart failure or intracranial hypertension. One key association is its use in cardiac catheterisation to evaluate haemodynamic status, where inaccurate readings can lead to misdiagnosis or inappropriate treatment.