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Phrenic nerve block caused by interscalene brachial plexus block: effects of digital pressure and a low volume of local anesthetic.
Reg Anesth Pain Med. 1999 May-Jun; 24(3):231-5.RA

Abstract

BACKGROUND AND OBJECTIVES

Interscalene brachial plexus block (ISB) is associated with phrenic block and diaphragmatic paralysis when high volumes (40-50 mL) of local anesthetic are injected. The goal of our study was to test if a low volume of local anesthetic administered while maintaining proximal digital pressure might more selectively block the brachial plexus and decrease the frequency of phrenic nerve block.

METHODS

Twenty healthy patients undergoing ISB for orthopedic surgery of the upper extremity were randomly allocated to receive either 20 mL 1.5% mepivacaine while proximal digital pressure to the site of puncture was performed, or 40 mL 1.5% mepivacaine without digital pressure. Spirometry and clinical data were evaluated at baseline, 10, and 90 minutes after accomplishing the block and after the motor and sensory block resolved. Diaphragmatic excursion during deep inspiration was also evaluated 90 minutes after the block was performed, with the patient in the sitting position.

RESULTS

Interscalene brachial plexus block produced diaphragmatic paralysis in all patients included in the study, as demonstrated by the pulmonary function testing and the chest radiograph. No significant differences were found in any of the parameters studied. At 10 minutes, baseline functional residual capacity had diminished by 34 +/- 10% in the 40 mL group and 37 +/- 13% in the 20 mL group. Maximum cephalad sensory dermatome level was also similar in both groups, being C 3 or above in all patients. Ipsilateral hemidiaphragmatic motion was similar in both groups (3.2 +/- 2.3 cm in the 40 mL group and 2.6 +/- 1.7 cm in the 20 mL group). However, in no case was dyspnea manifested.

CONCLUSIONS

Decreasing the volume of local anesthetic and applying proximal digital pressure to the site of injection is not effective in reducing the cervical block spread and the frequency or intensity of diaphragmatic paralysis during interscalene ISB.

Authors+Show Affiliations

Department of Anesthesiology, Hospital de Sant Boi, Sant Boi de Llobregat, Barcelona, Spain.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

10338173

Citation

Sala-Blanch, X, et al. "Phrenic Nerve Block Caused By Interscalene Brachial Plexus Block: Effects of Digital Pressure and a Low Volume of Local Anesthetic." Regional Anesthesia and Pain Medicine, vol. 24, no. 3, 1999, pp. 231-5.
Sala-Blanch X, Lázaro JR, Correa J, et al. Phrenic nerve block caused by interscalene brachial plexus block: effects of digital pressure and a low volume of local anesthetic. Reg Anesth Pain Med. 1999;24(3):231-5.
Sala-Blanch, X., Lázaro, J. R., Correa, J., & Gómez-Fernandez, M. (1999). Phrenic nerve block caused by interscalene brachial plexus block: effects of digital pressure and a low volume of local anesthetic. Regional Anesthesia and Pain Medicine, 24(3), 231-5.
Sala-Blanch X, et al. Phrenic Nerve Block Caused By Interscalene Brachial Plexus Block: Effects of Digital Pressure and a Low Volume of Local Anesthetic. Reg Anesth Pain Med. 1999 May-Jun;24(3):231-5. PubMed PMID: 10338173.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Phrenic nerve block caused by interscalene brachial plexus block: effects of digital pressure and a low volume of local anesthetic. AU - Sala-Blanch,X, AU - Lázaro,J R, AU - Correa,J, AU - Gómez-Fernandez,M, PY - 1999/5/25/pubmed PY - 1999/5/25/medline PY - 1999/5/25/entrez SP - 231 EP - 5 JF - Regional anesthesia and pain medicine JO - Reg Anesth Pain Med VL - 24 IS - 3 N2 - BACKGROUND AND OBJECTIVES: Interscalene brachial plexus block (ISB) is associated with phrenic block and diaphragmatic paralysis when high volumes (40-50 mL) of local anesthetic are injected. The goal of our study was to test if a low volume of local anesthetic administered while maintaining proximal digital pressure might more selectively block the brachial plexus and decrease the frequency of phrenic nerve block. METHODS: Twenty healthy patients undergoing ISB for orthopedic surgery of the upper extremity were randomly allocated to receive either 20 mL 1.5% mepivacaine while proximal digital pressure to the site of puncture was performed, or 40 mL 1.5% mepivacaine without digital pressure. Spirometry and clinical data were evaluated at baseline, 10, and 90 minutes after accomplishing the block and after the motor and sensory block resolved. Diaphragmatic excursion during deep inspiration was also evaluated 90 minutes after the block was performed, with the patient in the sitting position. RESULTS: Interscalene brachial plexus block produced diaphragmatic paralysis in all patients included in the study, as demonstrated by the pulmonary function testing and the chest radiograph. No significant differences were found in any of the parameters studied. At 10 minutes, baseline functional residual capacity had diminished by 34 +/- 10% in the 40 mL group and 37 +/- 13% in the 20 mL group. Maximum cephalad sensory dermatome level was also similar in both groups, being C 3 or above in all patients. Ipsilateral hemidiaphragmatic motion was similar in both groups (3.2 +/- 2.3 cm in the 40 mL group and 2.6 +/- 1.7 cm in the 20 mL group). However, in no case was dyspnea manifested. CONCLUSIONS: Decreasing the volume of local anesthetic and applying proximal digital pressure to the site of injection is not effective in reducing the cervical block spread and the frequency or intensity of diaphragmatic paralysis during interscalene ISB. SN - 1098-7339 UR - https://www.unboundmedicine.com/medline/citation/10338173/Phrenic_nerve_block_caused_by_interscalene_brachial_plexus_block:_effects_of_digital_pressure_and_a_low_volume_of_local_anesthetic_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1098-7339(99)90133-5 DB - PRIME DP - Unbound Medicine ER -