title: Transcutaneous continuous carbon dioxide tension monitoring reduced incidence, degree and duration of hypercapnia during combined regional anaesthesia and monitored anaesthesia care in shoulder surgery patients.
abstract: We studied the impact of transcutaneous continuous carbon dioxide tension (PtcCO2) monitoring on ventilation and oxygenation during monitored anaesthesia care (MAC) in patients scheduled for shoulder surgery with continuous interscalene block. 50 patients were randomised either to the intervention (I-group) or the control (C-group) group. In both groups MAC was performed using target controlled infusion of propofol and remifentanil. MAC regimen was adapted to PtcCO2 values in the I-group, whereas the C-group was blinded for these values. Primary outcome was the incidence, degree and duration of hypoventilation stages. In the I-group and the C-group the mean ± SD [range] of PtcCO2 and PaCO2 was 5.79 ± 0.84 [4.37] and 5.44 ± 0.59 [2.78] kPa, as well as 6.41 ± 1.17 [6.29] and 6.01 ± 0.96 [7.15] kPa. Periods of PtcCO2/PaCO2 > 6.5 kPa were 21.0 ± 35.7/1.2 ± 4.2 min in the I-group and 45.6 ± 40.0/18.6 ± 26.8 min in the C-group. Severe hypercapnia (PtcCO2 and/or PaCO2 > 7.5 kPa) was dected in 3/0 patients of the I-group and in 10/3 patients of the C-group. PtcCO2 and PaCO2 showed a strong correlation (r = 0.78), but only moderate agreement with a mean bias (LOA) of -0.37 (-1.69; +0.95) kPa showing an overestimation of the PaCO2. Sensitivity and specificity of PtcCO2 to detect changes of PaCO2 was 0.94 and 0.56, respectively. In no patient SpO2 or SaO2 values lower than 90% were measured. Despite a moderate agreement between PaCO2 and PtcCO2 the PtcCO2 monitoring significantly reduced incidence, degree and duration of hypercapnia in shoulder surgery patients with MAC.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Klinik Im Park, Seestrasse 220, 8027, Zurich, Switzerland, werner.baulig@hirslanden.ch.
authors.forename: Werner
authors.initials: W
authors.lastname: Baulig
authors.forename: Marija
authors.initials: M
authors.lastname: Keselj
authors.forename: Barbara
authors.initials: B
authors.lastname: Baulig
authors.forename: Sandra
authors.initials: S
authors.lastname: Guzzella
authors.forename: Alain
authors.initials: A
authors.lastname: Borgeat
authors.forename: José
authors.initials: J
authors.lastname: Aguirre
mesh_terms: D000328:Adult; D000765:Anesthesia, Conduction / Q000379:methods*; D018686:Anesthetics, Intravenous / Q000627:therapeutic use; D001785:Blood Gas Monitoring, Transcutaneous / Q000379:methods*; D002245:Carbon Dioxide / Q000737:chemistry*; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000175:diagnosis* / Q000517:prevention & control; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000737:chemistry; D010880:Piperidines / Q000627:therapeutic use; D015742:Propofol / Q000627:therapeutic use; D011446:Prospective Studies; D000077208:Remifentanil; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012782:Shoulder / Q000601:surgery*
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D002245:Carbon Dioxide; D000077208:Remifentanil; D010100:Oxygen; D015742:Propofol