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Oesophageal Manometry
High-resolution oesophageal manometry is an examination of the oesophagus. The procedure determines how the muscle of the oesophagus and the sphincters (valves) work by measuring pressures generated by the oesophageal muscles and the sphincter. Contents in the oesophagus are controlled by two sphincters; the voluntary upper oesophageal sphincter (UOS) and the involuntary lower oeosphageal sphincter (LOS).
1. Upper and lower sphincters remain contracted at rest.
2. A swallow starts with the relaxation of the upper oesophgeal sphincter (UOS) to allow food through.
3. A strong contraction at the UOS propels its content down the oesophagus, while contractions just behind the content help push it along. Meanwhile, the lower oesophageal sphincter (LOS) relaxes early to allow for the passage of trapped air.
4. The contents moves past the relaxed LOS into the stomach before the LOS contracts again to prevent back-flow.
High-resolution oesophageal manometry pressure map of a normal swallow.
1. Sphincters at rest remain contracted; UOS has a stronger contraction than the LOS.
2. The UOS opens briefly to allow contents through, followed a contraction to push contents along.
3. Muscles along the oesophagus contract behind the content as it guide the contents down the oesophagus. The LOS relaxes.
4. Contents pass through the LOS into the stomach before the LOS returns to contracted state.
Preparation for high-resolution oesophageal manometry (HRM)
- Continue all other forms of medication as prescribed
- Stop eating and drinking 3 hours prior to the test
- The studies are considered painless but, lignocaine spray is used to numb the nose and back of the throat
- The time required for each appointment is approximately 1 hour
A small flexible catheter (thinner than a drinking straw) is passed gently through your nasal passage into the oesophagus and easily swallowed into the stomach.
At the end of the catheter there are pressure sensors which will measure the pressure of the upper and lower oesophageal valves, as well as the contractions of the oesophagus as you swallow.
The other end of the catheter, which emerges from the nose, is connected to a computer monitoring system which records the internal pressures during the test. Lignocaine spray will be used on the patient before the test begins, to help with numbing the nose and back of the throat.
| Manoeuvres | What are you asked to do? | What are we measuring? |
|---|---|---|
| Resting | Relax and remain still for 30 seconds | Baseline pressure measurements are taken |
| Single water swallows | Drink water volumes of 5 mL, 10 mL and 20 mL in a single swallow | Oesopheageal and sphincter function |
| Rapid swallows | Asked to drink small volumes of water in a quick succession of swallows | Simulate normal water swallows, evaluate oesophageal function during rapid succession of swallows |
| Semi-solid and solid swallows | Swallow a spoonful of custard or Jelly and a small marshmallow | Evaluate swallow function with different content (bolus) consistencies |
Oesophageal physiological and motility disorders
Reflux physiology
Acid reflux is a common disorder that occurs in the majority of the population. However, in patients with severe symptoms oesophageal defects such as weak LOS resting pressure or hiatus hernia may be the cause. A LOS that is not appropriately contracted at rest can promote back-flow of stomach content after meals or during sleep. A hiatus hernia is a pouch formed below the LOS that can trap stomach content to cause reflux. Treatment options are varied, from protein pump inhibitors (PPI) to fundoplication surgery, and dependent on severity.
Achalasia
Achalasia occurs when the LOS does not relax during a swallow. This causes the blockage of content in the oesophagus and corresponding chest pains during swallowing. Achalasia is also accompanied by aperistalsis or spasms in the oesophagus which can further hinder the movement of content. Treatment for achalasia involves the relaxation of LOS, either by muscle relaxants, botox injection, or Heller myotomy surgery.
Oesopahgeal spasm
Uncoordinated contractions in the oesophagus can cause spasms which leads to a blockage of content during swallows. Spastic contractions can occur along the length of the oesophagus or isolated to specific areas. Treatment of oesophageal spasm involves muscle relaxants or botox injections in specific areas.
Aperistalsis
The absence of oesophageal contractions can be caused by neuropathic disorders or connective tissue disorders. Treatment options involve taking motility promoters or the management of primary underlying disorder.
