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Hypoxaemia and myocardial ischaemia during colonoscopy
C Holm1, M Christensen, V Rasmussen
1Dept. of Surgery, Sundby Hospital, Copenhagen, Denmark.
Insights
Myocardial ischaemia can occur during colonoscopy, with associated hypoxaemia and tachycardia. This study investigated these cardiac events during routine colonoscopies.
Area of Science:
- Cardiology
- Gastroenterology
- Critical Care Medicine
Background:
- Myocardial ischaemia, indicated by ST-segment deviation on electrocardiogram (ECG), may occur during colonoscopy.
- The underlying pathogenic mechanisms for myocardial ischaemia during colonoscopy are not fully understood.
- This study aimed to evaluate the incidence of arterial hypoxaemia, tachycardia, and myocardial ischaemia during routine colonoscopy.
Purpose of the Study:
- To assess the occurrence of myocardial ischaemia during colonoscopy.
- To investigate the association between myocardial ischaemia, arterial hypoxaemia, and tachycardia during the procedure.
- To compare the incidence of myocardial ischaemia during colonoscopy with that during upper endoscopy.
Main Methods:
- Eighteen patients undergoing colonoscopy under conscious sedation without supplemental oxygen were studied.
- Continuous monitoring of arterial oxygen saturation via pulse oximetry and ECG using a Holter tape recorder was performed.
- Data on ST-segment deviation, oxygen saturation, and heart rate were collected during the colonoscopy procedure.
Main Results:
- Arterial oxygen desaturation (45%) and tachycardia (35%) were common findings during colonoscopy.
- Two patients (approximately 11%) exhibited signs of myocardial ischaemia (ST depression and ST elevation), which resolved upon colonoscope withdrawal.
- Myocardial ischaemia in these patients coincided with tachycardia and, in one case, with arterial hypoxaemia.
Conclusions:
- Myocardial ischaemia can occur during routine colonoscopy, albeit less frequently than reported for upper endoscopy.
- Tachycardia and/or hypoxaemia may be associated with myocardial ischaemia during colonoscopy.
- Further research is needed to elucidate the roles of tachycardia, hypoxaemia, and viscerocardiac reflexes in the pathogenesis of colonoscopy-induced myocardial ischaemia.
Background:
Myocardial ischaemia (defined as ST-segment deviation on electrocardiogram (ECG)) may occur during colonoscopy, but the pathogenic mechanisms are unknown. We have evaluated the occurrence of arterial hypoxaemia, tachycardia, and myocardial ischaemia during routine colonoscopy.
Methods:
Eighteen patients underwent colonoscopy under conscious sedation and without supplementary oxygen. Arterial oxygen saturation was measured by continuous pulse oximetry, and ECG was monitored continuously with a Holter tape recorder during the procedure.
Results:
Arterial oxygen desaturation and tachycardia were common during colonoscopy and occurred in 45% and 35% of patients, respectively. Two patients developed signs of myocardial ischaemia during the colonoscopy: one case of ST depression (1.7 mV) and one case of ST elevation (4.3 mV). In both patients the ST deviation disappeared when the colonoscope was retracted. Myocardial ischaemia occurred in both patients simultaneously with tachycardia, and in one of these arterial hypoxaemia was also present.
Conclusions:
Myocardial ischaemia occurs during routine colonoscopy, but with a lower incidence than previously reported during upper endoscopy. Myocardial ischaemia during colonoscopy may be associated with tachycardia and/or hypoxaemia. Further studies should clarify the relative role of tachycardia, hypoxaemia, and viscerocardiac reflexes in the pathogenesis of myocardial ischaemia during colonoscopy.