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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Thoracic sympathetic block reduces respiratory system compliance

Full text
Author(s):
Fábio Ely Martins Benseñor [1] ; Joaquim Edson Vieira [2] ; José Otávio Costa Auler Júnior [3]
Total Authors: 3
Affiliation:
[1] Universidade de São Paulo. Faculdade de Medicina. Hospital das Clínicas - Brasil
[2] Universidade de São Paulo. Faculdade de Medicina. Hospital das Clínicas - Brasil
[3] Universidade de São Paulo. Faculdade de Medicina. Hospital das Clínicas - Brasil
Total Affiliations: 3
Document type: Journal article
Source: São Paulo Medical Journal; v. 125, n. 1, p. 9-14, 2007-01-00.
Abstract

CONTEXT AND OBJECTIVE: Thoracic epidural anesthesia (TEA) following thoracic surgery presents known analgesic and respiratory benefits. However, intraoperative thoracic sympathetic block may trigger airway hyperreactivity. This study weighed up these beneficial and undesirable effects on intraoperative respiratory mechanics. DESIGN AND SETTING: Randomized, double-blind clinical study at a tertiary public hospital. METHODS: Nineteen patients scheduled for partial lung resection were distributed using a random number table into groups receiving active TEA (15 ml 0.5% bupivacaine, n = 9) or placebo (15 ml 0.9% saline, n = 10) solutions that also contained 1:200,000 epinephrine and 2 mg morphine. Under general anesthesia, flows and airway and esophageal pressures were recorded. Pressure-volume curves, lower inflection points (LIP), resistance and compliance at 10 ml/kg tidal volume were established for respiratory system, chest wall and lungs. Student’s t test was performed, including confidence intervals (CI). RESULTS: Bupivacaine rose 5 ± 1 dermatomes upwards and 6 ± 1 downwards. LIP was higher in the bupivacaine group (6.2 ± 2.3 versus 3.6 ± 0.6 cmH2O, p = 0.016, CI = -3.4 to -1.8). Respiratory system and lung compliance were higher in the placebo group (respectively 73.3 ± 10.6 versus 51.9 ± 15.5, p = 0.003, CI = 19.1 to 23.7; 127.2 ± 31.7 versus 70.2 ± 23.1 ml/cmH2O, p < 0.001, CI = 61 to 53). Resistance and chest wall compliance showed no difference. CONCLUSION: TEA decreased respiratory system compliance by reducing its lung component. Resistance was unaffected. Under TEA, positive end-expiratory pressure and recruitment maneuvers are advisable. (AU)