Thoracic sympathetic block reduces respiratory system compliance

Sao Paulo Medical Journal

Fábio Ely Martins Benseñor¹  Joaquim Edson Vieira¹  José Otávio Costa Auler Júnior¹ 

[1] ,Universidade de São Paulo Faculdade de Medicina Hospital das Clínicas São Paulo ,Brazil

关键词: Epidural anesthesia;    Autonomic nerve block;    Respiratory mechanics;    Lung compliance;    Airway resistance;    Anestesia epidural;    Bloqueio nervoso autônomo;    Mecânica respiratória;    Complacência pulmonar;    Resistência das vias respiratórias;   

DOI  :  10.1590/S1516-31802007000100003

来源: SciELO

【 摘 要 】

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.

【 授权许可】

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