GI Testing

Question 1

What is oesophageal HRM used to assess?

Answer 1

Oesophageal motility and UOS and LOS/OGJ function
Motility, contractile, and swallowing dysfunctions

Question 2

Patient prep for oesophageal HRM

Answer 2

Fasting 8h prior, no meds anywhere between 48h and 2h prior

Question 3

Procedure of oesophageal HRM

Answer 3

Catheter inserted through nasal cavity into oesophagus - swallow to allow entry

x10 single swallows 5ml liquid (essential)
x5 single swallows of 5ml liquid (essential)
Rapid swallows 2ml every 2s x5 (provocative)
Rapid drinking 200ml (provocative)
Solid swallows bread/biscuit (provocative)

Question 4

Oesophageal HRM Metrics

Answer 4

Integrated relaxation pressure (IRP)
Distal contractile integral (DCI)
Contractile deceleration point (CDP)
Distal latency (DL)

Question 5

IRP

Answer 5

Integrated Relaxation Pressure - Measurement of LOS relaxation
4 seconds of lowest pressures of LOS within the 10s window that occurs as the LOS begins to relax from the initiation of a swallow
Normal <15mmHg
Impaired relaxation (achalasia/OGJOO) >15mmHg

Question 6

DCI

Answer 6

Distal Contractile Integral - Measurement of the strength/vigour of distal oesophageal contractions

Normal 450-8000mmHg/s/cm
Hypercontractile >8000mmHg/s/cm
Weak/ineffective 100-450mmHg/s/cm
Failed <100mmHg/s/cm

Question 7

CDP

Answer 7

Contractile Deceleration Point - represents the point of the distal oesophagus where peristaltic waves begin to slow as bolus reaches the LOS.
Peristalsis occurs up until the CDP after which bolus moves into stomach with gravity and the oesophagus relaxes

Question 8

DL

Answer 8

Distal Latency - Measures the time between the start of swallowing and the end of contractions at the distal oesophagus (UOS relaxation to CDP)
i.e the speed and progression of peristaltic contractions along the oesophagus
Normal >4.5s
Premature spastic contractions <4.5s

Question 9

Chicago Classification

Answer 9

Standardised method of interpreting oesophageal HRM with threshold values for metrics (IRP, DCI, DL)

Question 10

Achalasia I
Mechanism and HRM metrics

Answer 10

LOS dysfunction with absent peristaltic waves and pressure - degenerated myenteric plexus no muscular tone
Elevated IRP >15mmHg

Question 11

Achalasia II
Mechanism and HRM metrics

Answer 11

LOS dysfunction with some muscular tone but absent peristalsis - just pressure/squeezing
Elevated IRP >15mmHg
Noted pressurisation in oesophageal body

Question 12

Achalasia III
Mechanism and HRM metrics

Answer 12

LOS dysfunction with premature/spastic peristaltic waves
Elevated IRP >15mmHg
Shortened DL <4.5s

Question 13

Apart from achalasia, what other conditions can be identified on oesophageal HRM

Answer 13

Oesophageal-gastric junction outflow obstruction (OGJOO), jackhammer (hypercontractile) oesophagus, distal oesophageal spasm (spastic oesophagus), ineffective oesophageal motility (IOM)

Question 14

Aperistalsis (Absent Contractility)

Answer 14

Absent peristaltic waves but normal LOS relaxation (distinguish from achalasia I)

Question 15

Jackhammer (Hypercontractile) Oesophagus
Mechanism and HRM metrics

Answer 15

Excessively strong, forceful contractions due to excessive excitatory signals to oesophageal musculature, but normal peristaltic sequence (not premature).
DCI >8000mmHg/s/cm
IRP normal <15mmHg
DL normal >4.5s

Question 16

Distal Oesophageal Spasm (Spastic Oesophagus)
Mechanism and HRM metrics

Answer 16

Uncoordinated, spasitc, premature contractions in distal oesophagus but normal LOS relaxation (distinguish from achalasia III)
DL shortened <4.5s
Normal IRP and DCI

Question 17

Ineffective Oesophageal Motility
Mechanism and HRM metrics

Answer 17

Weak/uncoordinated/ineffective contractions
Low DCI 450-100mmHg/s/cm
Normal IRP
Must occur in at least 50% of swallows