title: Short term general anesthesia for retro-bulbar block in ophthalmic surgery generates no significant hypercapnia.
abstract: To assess the impact of short time hypnosis for retro-bulbar anesthesia on ventilation in patients undergoing ophthalmic surgery of the anterior eye chamber. In all patients, a combined continuous transcutaneous carbon dioxide tension (PtcCO2) and partial oxygen saturation (SpO2) measurement was applied in addition to routine monitoring. To enable unconscious application of retro-bulbar anesthesia, intravenous thiopental was given in one to multiple bolus doses. Transient breathing support included chin lift, Esmarch maneuver and manual hand-bag ventilation via face mask. Main endpoints were apnea time, recovery time according to the Richmond Agitation Sedation Scale, as well as SpO2and PtcCO2readings at predefined time points. Fifty-two patients with a mean age of 68 ± 13 years were included. Average thiopental dose was 2.7 ± 0.6 mg/kg. In seven (13.5%) patients repeated doses of thiopental were necessary to a total of 3.3 ± 1.1 mg/kg. Except one patient, no severe, significant or clinical relevant hypercapnia or desaturation periods were observed, and the occurring elevation of PtcCO2values did not correlate with the application of repeated doses of thiopental or the need for the Esmarch maneuver. Higher PtcCO2values were associated with the presence of hypertension and smoking. Apnea (p < 0.001) and recovery (p = 0.003) time were significantly prolonged in the patients needing the Esmarch maneuver. Short term anesthesia with thiopental in ophthalmic surgery is associated with a mild but not clinically relevant hypercapnia.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Hirslanden Klinik im Park, Seestrasse 220, 8027, Zurich, Switzerland. werner.baulig@hirslanden.ch.
authors.forename: Werner
authors.initials: W
authors.lastname: Baulig
authors.affiliation: Institute of Anesthesiology, University Hospital Zurich, 8091, Zurich, Switzerland.
authors.forename: Monica
authors.initials: M
authors.lastname: Weber
authors.affiliation: Institute of Anesthesiology, University Hospital Zurich, 8091, Zurich, Switzerland.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Beck-Schimmer
authors.affiliation: Institute of Anesthesiology, University Hospital Zurich, 8091, Zurich, Switzerland.
authors.forename: Oliver M
authors.initials: OM
authors.lastname: Theusinger
authors.affiliation: Institute of Anesthesiology, University Hospital Zurich, 8091, Zurich, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Biro
mesh_terms: D000368:Aged; D000768:Anesthesia, General / Q000009:adverse effects / Q000379:methods*; D001049:Apnea / Q000150:complications; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000378:metabolism; D004867:Equipment Design; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures / Q000379:methods*; D010100:Oxygen / Q000378:metabolism; D012121:Respiration, Artificial; D013874:Thiopental / Q000008:administration & dosage
chemical_list: D002245:Carbon Dioxide; D013874:Thiopental; D010100:Oxygen
keywords: Ophthalmic surgery; PtcCO2 monitoring; Thiopental anesthesia