title: Capnographic monitoring for carbon dioxide insufflation during endoscopic submucosal dissection: comparison of transcutaneous and end-tidal capnometers [corrected].
abstract: BACKGROUND
  The use of carbon dioxide (CO(2)) insufflation during endoscopic procedures is effective in reducing patient discomfort caused by bloating. However, transcutaneous arterial CO(2) (PtCO(2)) monitoring usually is required for safety during long endoscopic procedures. To evaluate a new capnometer for monitoring end-tidal carbon dioxide (EtCO(2)) concentrations and to compare PtCO(2) with EtCO(2) measured in the same patient, a prospective comparative study of EtCO(2) and PtCO(2) values measured simultaneously was designed.
  
  
  METHODS
  The study enrolled 20 consecutive patients (18 men and two women; mean age, 70.1 years) with upper gastrointestinal neoplasms scheduled for endoscopic submucosal dissection (ESD) using conscious sedation with CO(2) insufflation, and EtCO(2) and PtCO(2) were simultaneously measured by each capnometer. Patient status was evaluated before ESD by the American Society of Anesthesiologists (ASA) physical status classification system, and eight patients were judged as class 1, nine patients as class 2, and three patients as class 3. The exclusion criteria ruled out patients with chronic obstructive pulmonary disease or ASA class 4 or 5 physical status. The correlation between EtCO(2) and PtCO(2) values and the availability of EtCO(2) capnography were investigated.
  
  
  RESULTS
  The mean EtCO(2) value during ESD was 34.7 ± 4.5 mmHg, and the mean PtCO(2) value was 51.6 ± 2.4 mmHg. There was a statistically significant correlation between EtCO(2) and PtCO(2) (r = 0.331; P = 0.002). Hypoxic events (<90% oxygen saturation [SpO(2)]) caused by decreased respiratory rate occurred for 12 patients. In 10 (83%) of 12 events, a significant reduction in EtCO(2) was seen before the decrease in SpO(2).
  
  
  CONCLUSIONS
  The EtCO(2) values correlated with the PtCO(2) values, and the respiratory monitoring methods allowed earlier detection of hypoxia during ESD with conscious sedation than transcutaneous monitoring. The EtCO(2) capnometer was considered to be available for the ESD procedure with the patient under conscious sedation using CO(2) insufflation.
authors.affiliation: Second Department of Internal Medicine, Faculty of Medicine, Shimane University, Izumo, Japan.
authors.forename: Ryusaku
authors.initials: R
authors.lastname: Kusunoki
authors.forename: Yuji
authors.initials: Y
authors.lastname: Amano
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yuki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Oka
authors.forename: Mayumi
authors.initials: M
authors.lastname: Okada
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Tada
authors.forename: Goichi
authors.initials: G
authors.lastname: Uno
authors.forename: Ichiro
authors.initials: I
authors.lastname: Moriyama
authors.forename: Norihisa
authors.initials: N
authors.lastname: Ishimura
authors.forename: Shunji
authors.initials: S
authors.lastname: Ishihara
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kinoshita
mesh_terms: D000368:Aged; D019296:Capnography / Q000295:instrumentation*; D002245:Carbon Dioxide / Q000097:blood*; D004210:Dissection; D016099:Endoscopy, Gastrointestinal / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis; D007327:Insufflation / Q000295:instrumentation*; D007902:Length of Stay; D008297:Male; D010313:Partial Pressure; D011446:Prospective Studies
chemical_list: D002245:Carbon Dioxide