An increased resting pressure (> 45 mm Hg) in the lower sphincter can also be detected in approx. 50% of patients. Based on the manometric findings, 3 subtypes of achalasia are differentiated according to the Chicago Classification (see general information). This distinction is now important for the therapeutic approach.
During esophageal manometry, a thin catheter with multiple pressure measuring probes (high-resolution esophageal manometry, HRM) is inserted through the nose of the awake patient after anesthetizing the nose with a gel. The patient can drink some water with a straw, which makes the insertion much easier due to the natural peristalsis. The examination is harmless and is tolerated by >90% of patients.
The test protocol is firmly defined and includes single sips, free rapid drinking of water (MRS – mutliple rapid swallows) and a test meal of cooked rice. The measured pressure curves are then assessed by experienced examiners.