Periprocedure Outcome During Upper Endoscopy in Morbidly Obese Patients : A Prospective Study

Pornthep Prathanvanich, MD, Bipan Chand, MD

Loyola University Chicago Stritch School of Medicine Chicago

Background
One concern during endoscopy in the obese is the effects of sedation. The obese patients has reduced functional residual capacity (FRC), vital capacity and total lung volume. These changes in lung volume decrease exponentially with the higher body mass index (BMI). In addition, the ventilation/perfusion mismatches can develop rapidly in these patients.
Aim of this study is to determine the effects of sedation during the evaluation for bariatric surgery. The study will specifically evaluate the cardiopulmonary changes during moderate sedation.

METHODS

After IRB approval, diagnostic upper gastrointestinal endoscopies were performed in 18 consecutive morbidly obese patients ( 7 men, 11 women; mean age 46.22± 10.2 range 25-62 years ). Sedation was administered with propofol and midazolam. Monitoring included continuous capnography, oxygenation, HR and intermittent BP by anesthesiologist or CRNA. Data on sedation, periprocedure outcomes, critical events including cardiorespiratory changes and examination times were recorded. Endoscopic finding were also recorded.

RESULTS

The mean body mass index was 48.96± 10.78 ( range, 35.41-70 ), kg/m2 . The mean procedure duration time was 11.17±1.65 ( range, 10-15 ) min, and the endoscopy took 7±1.029 ( range, 6-10 ) min. The mean propofol dosage was 150.56±41.51 ( range,70-200 ) mg, and midazolam dosage was 2.22±0.94 ( range, 2-6 ) mg. Mean of level sedation by MOAA was 2.78±0.42 ( range, 2-3 )
11/18 (61%) of patients had pathological finding including 7/18 for antral gastritis, 1/18 for duodenitis, 2/18 for gastric polyps, and 1/18 for submucosal mass. Only 7/18 ( 29% ) of patients had normal findings.

Eight patients ( 8/18, 44.44% ) had increased end-tidal CO2 level more than 10 from baseline which was statistically significant in relation to male ( p = 0.00 ), excess weight ≥ 100 kg ( p = 0.02 ), waist : hip ratio ≥ 1 ( p = 0.003 ) , history of OSA ( p = 0.04 ) and an need increased FiO2 of more than 0.4 L ( p= 0.001 ). What was not associated with an increased end-tidal CO2 level more than 10 from baseline was a BMI > 50 (p = 0.06), neck circumference ≥ 40 cm ( p = 0.18 ), SpO2 < 90 ( p = 0.06 ), or a HR or SBP change > 25% ( p = 0.67 and 0.18 respectively ). 17 patients were administered the Epworth Sleepiness Scale which also was not predictive of change in end-tidal CO2 level more than 10 from baseline ( p = 0.529 ).

CONCLUSION
Capnography provided real-time indication of changes of adequate ventilation before cardiorespiratory parameters changed. Capnography can detect early phases of respiratory depression, allowing a more precise and safer titration of medications, thereby reducing adverse outcomes associated with sedation in the morbidly obese patient.

Although no controlled study has examined whether additional monitoring (capnography ) during upper endoscopy with sedation in the morbidly obese patient improves outcomes, extended/advanced monitoring seems to offer an advantage over conventional monitoring.


Session: Poster Presentation

Program Number: P458

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