Conscious sedation and cardiorespiratory safety during colonoscopy

M Ristikankare, R Julkunen, Matti Mattila, Tomi Laitinen, S X Wang, M Heikkinen, E Janatuinen, J Hartikainen

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


BACKGROUND: Cardiorespiratory events during colonoscopy are common. The effect of sedative premedication on cardiorespiratory parameters during colonoscopy has not been studied in controlled, prospective trials.

METHODS: One hundred eighty patients undergoing colonoscopy were divided into 3 groups: (1) sedation with intravenous midazolam (midazolam group); (2) sedation with intravenous saline (placebo group); and (3) no intravenous cannula (control group). Arterial oxygen saturation (SaO(2)), systolic and diastolic blood pressure and continuous electrocardiogram were recorded prior to, during and after the endoscopic procedure.

RESULTS: Midazolam produced lower SaO(2) values during colonoscopy compared with placebo or control groups (p < 0.001, repeated measures analysis of variance). Systolic and diastolic blood pressure during colonoscopy were lower in the midazolam group than in the placebo group (p < 0.01 and p < 0.05, respectively), but no difference was found between the midazolam and the control groups. Hypotension (systolic blood pressure less than 100 mm Hg) occurred more frequently in the midazolam group (19%) than in the placebo (3%; p < 0.01) or control groups (7%; p < 0.05). ST-segment depression developed in 7% of patients during the recording with no difference between the groups. In 75% of cases ST-depression appeared prior to the endoscopic procedure.

CONCLUSIONS: Premedication with midazolam induced a statistically significant decrease in arterial oxygen saturation and increased the risk for hypotension. However, colonoscopy proved to be a safe procedure both with and without sedation.

Original languageEnglish (US)
Pages (from-to)48-54
Number of pages7
JournalGastrointestinal Endoscopy
Issue number1
StatePublished - Jul 2000


  • Adult
  • Analysis of Variance
  • Blood Pressure Determination
  • Cardiovascular Physiological Phenomena
  • Colonic Diseases
  • Colonoscopy
  • Conscious Sedation
  • Electrocardiography
  • Female
  • Hemodynamics
  • Humans
  • Hypnotics and Sedatives
  • Infusions, Intravenous
  • Male
  • Midazolam
  • Middle Aged
  • Monitoring, Physiologic
  • Oxygen Consumption
  • Probability
  • Prospective Studies
  • Reference Values
  • Respiratory Physiological Phenomena
  • Risk Assessment
  • Clinical Trial
  • Comparative Study
  • Journal Article
  • Randomized Controlled Trial


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