Changes in transcutaneous carbon dioxide, oxygen saturation, and respiratory rate after interscalene block

South Med J. 2004 Jan;97(1):21-4. doi: 10.1097/01.SMJ.0000054425.08030.B0.

Abstract

Background: We used transcutaneous (TC) carbon dioxide (CO2) monitoring to prospectively evaluate changes in respiratory status after interscalene anesthesia in 45 adults (40 successful and 5 unsuccessful blocks).

Methods: TC-CO2 oxygen saturation and respiratory rate were recorded every minute for 5 minutes before block and every 2 minutes for a total of 30 minutes (15 data sets) after injection of the local anesthetic solution.

Results: After successful block, TC-CO2 increased from 41 +/- 5 mm Hg to a maximum value of 44 +/- 6 mm Hg (P < 0.0001) and the respiratory rate increased from 14 +/- 2 breaths/min to a maximum of 20 +/- 4 breaths/min (P < 0.001). The increase in TC-CO2 was > or = 5 mm Hg in 11 patients and > or = 10 mm Hg in 4 patients, with a maximum increase of 12 mm Hg. Of the 600 TC-CO2 data points recorded (15 each from the 40 patients with a successful block), 62 (10.3%) showed a TC-CO2 value of 50 mm Hg or greater, with a maximum value of 57 mm Hg. No significant change in TC-CO2 or respiratory rate was seen in the five patients with unsuccessful block.

Conclusion: After interscalene blockade, we found an increase in respiratory rate and hypercarbia that resulted in no clinically significant effect.

MeSH terms

  • Amides / pharmacology
  • Analgesics, Opioid / therapeutic use
  • Anesthetics, Local / pharmacology
  • Arm / surgery
  • Blood Gas Monitoring, Transcutaneous*
  • Brachial Plexus*
  • Bupivacaine / analogs & derivatives
  • Bupivacaine / pharmacology
  • Female
  • Fentanyl / therapeutic use
  • Humans
  • Hypnotics and Sedatives / therapeutic use
  • Levobupivacaine
  • Lidocaine / pharmacology
  • Male
  • Midazolam / therapeutic use
  • Middle Aged
  • Nerve Block / methods*
  • Prospective Studies
  • Respiratory Mechanics / drug effects*
  • Ropivacaine
  • Shoulder / surgery

Substances

  • Amides
  • Analgesics, Opioid
  • Anesthetics, Local
  • Hypnotics and Sedatives
  • Ropivacaine
  • Lidocaine
  • Levobupivacaine
  • Midazolam
  • Fentanyl
  • Bupivacaine