Post-operative epidural analgesia: Effects on lung volumes

Abstract

FUNCTIONAL RESIDUAL CAPACITY (FRC) is reduced following upper abdominal operations under general anaesthesia. The changes which have been reported <1-5) are summarized in Table I. A number of factors can be responsible for the changes observed.The reduction of FRC which follows induction of general anaesthesia may persist. The cause for this reduction is still undetermined, but the fall is not progressive with time and is related to body size. (6,7) Loss of lung volume by atelectasis or oedema will reduce FRC, as will an increase in expiratory muscle activity. Abdominal distension by pneumoperitoneum and bowel distension and incisional pain can be responsible.In all probability, all these factors play a role. The present study was undertaken to determine the role of post-operative pain in reducing FRC and vital capacity (VC) and the efficacy of epidural analgesia in reversing these changes. SUBJECT MATERIALEight patients (five females and three males) scheduled for elective upper abdominal operations were studied. They were clinically free of cardiorespiratory disease, except for patient No. 5 who had mild chronic bronchitis. The ages ranged from 34 to 67 years (mean 42.5), height varied from 145 to 183 cm (mean 159 cm), and weight from 40.9 to 88 kg (mean 67.9 kg). Consent was obtained in each case following explanation of the purpose and methods of the study. EXPERIMENTAL PROTOCOLAll subjects were studied in the supine position in the Recovery Room. Preoperative (control) measurements were made on the day of operation with the patients fasted overnight and without premedication. Measurements of FRC and VC were made following the placement of lumbar epidural and intravenous catheters by standard techniques, without injection of any anaesthetic agent. During the operation, lidocaine epidural anaesthesia was supplemented with general anaesthesia using thiopentone, endotracheal N20: 02, and meperidine. The

Epidural anesthesia and pulmonary function

“…In fact, thoracic epidural anesthesia leads to an improvement of lung function. In 1975, Whaba et al [28] demonstrated that the reduction in functional residual capacity (FRC) improved from 21.7% to 15.9%, and the reduction in VC improved from 63% to only 45% when epidural anesthesia was used following upper abdominal surgery. Thirteen years later, Mankikian et al [29] used epidural anesthesia in patients who underwent abdominal aortic surgery with a complete longitudinal abdominal incision, and demonstrated an improvement in VC from 1380 ± 115 ml to 1930 ± 144 ml.…”

Early Removal of Chest Drainage Tubes and Oxygen Support After a Lobectomy for Lung Cancer Facilitates Earlier Recovery of the 6-Minute Walking Distance

“…10 Despite the short duration of epidural analgesia, the subjective group did not suffer any increase of pain and also showed a higher postoperative VC and 6MWD than the control group. Therefore, the decrease in the postoperative impairment of 6MWD and VC in the subjective group should not be influenced by postoperative pain.…”

Gallbladder bed irrigation with bupivacaine improves pulmonary functions after laparoscopic cholecystectomy

“…As postoperative pain was accepted as a major factor [15,16], pulmonary restrictive effect was independent of pain. Several studies demonstrated that anesthetic wound infiltration and intercostal nerve blocks do not completely prevent the restrictive defect after abdominal surgery [15,[17][18][19]. Rademaker et al [20] provides adequate pain relief by extradural analgesia after laparoscopic cholecystectomy, but did not observe improvement in lung dysfunction Although Peters et al [21] has underlined residual pneumoperitoneum as a factor of impaired diaphragmatic function after laparoscopic cholecystectomy, carbon dioxide pneumoperitoneum alone, such as for diagnostic laparoscopy, does not impair diaphragmatic function [22].…”