Effects of intercostal nerve blocks (bupivacaine 0.25% and etidocaine 0.5%) on chest wall mechanics in healthy men

Efficacy of Intercostal Nerve Block for Pain Control After Percutaneous Nephrolithotomy: A Systematic Review and Meta-Analysis

Background: We aimed to assess the efficacy of intercostal nerve block (ICNB) for pain relief after percutaneous nephrolithotomy (PCNL).

Methods: An electronic search of the databases of PubMed, Science Direct, BioMed Central, CENTRAL, Embase, and Google Scholar was conducted. All types of studies conducted on adult patients undergoing PCNL, comparing ICNB with control or any other anesthetic method, and reporting postoperative pain outcomes were included.

Results: Six studies were included. Studies compared ICNB with peritubal (PT) infiltration and with control. Pooled analysis of ICNB vs. PT infiltration indicated no difference between the two groups for pain scores at 6–8 h (MD −0.44; 95% CI −3.41, 2.53; I² = 99%; p = 0.77), 12 h (MD −0.98; 95% CI −4.90, 2.94; I² = 99%; p = 0.62) and 24 h (MD 0.16; 95% CI −0.90, 1.21; I² = 88%; p = 0.77). Time for first analgesic demand was also not significantly different between the two groups. Meta-analysis of ICNB vs. control indicated statistical significant difference in pain scores between the two groups at 8 h (MD −1.55; 95% CI −2.60, −0.50; I² = 47%; p = 0.04), 12 h (SMD −2.49; 95% CI −4.84, −0.13; I² = 96%; p = 0.04) and 24 h (SMD −1.22; 95% CI −2.12, −0.32; I² = 88%; p = 0.008). The total analgesic requirement in morphine equivalents was not significantly different between the two groups.

Conclusions: ICNB may be effective in reducing postoperative pain after PCNL. However, its efficacy may not be greater than PT infiltration. Current evidence is from a limited number of studies. Further, high-quality randomized controlled trials are needed to provide robust evidence.

Analgesia after lateral thoracotomy in dogs. Epidural morphine vs. intercostal bupivacaine

One of two analgesic treatments was randomly assigned to 40 dogs undergoing lateral thoracotomy. Group E (20 dogs) received an epidural injection of morphine (0.1 mg/kg) before surgery. Group I (20 dogs) received injections of bupivacaine around five intercostal nerves when the thorax was about to be closed. All dogs were given an opioid as part of their preoperative medication (meperidine or butorphanol), followed by thiopental for induction and halothane or methoxyflurane for maintenance of anesthesia. Scores were assigned for pre-operative demeanor and response to restraint and injection. Alertness, undisturbed pain behavior, and response to palpation of the wound were assessed 3, 6, 12, and 24 hours after surgery. Dogs that appeared uncomfortable were given analgesics. Blood for evaluation of arterial blood gases was obtained at 3 and 6 hours after surgery. The person scoring the dogs was blinded to the treatment given. There were no statistically significant differences between the groups. Group E contained more "nervous" dogs (12 vs. 6) and more dogs in group E received postoperative analgesics (8 vs. 2). Both techniques appeared to provide adequate analgesia for most dogs.

Respiratory performance after upper abdominal surgery. A comparison of pain relief with intercostal blocks and centrally acting analgesics

The respiratory capacity was studied during the first 2 days postoperatively in 94 patients, aged 19 to 75 years and undergoing surgery through an upper abdominal incision. Postoperative pain relief was randomly administered, either by intercostal block (i.c.b.) and centrally acting analgesics on demand, or by centrally acting analgesics alone. Respiratory studies comprising forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEF) and analysis of arterial blood gases were made. Bilateral i.c.b. given after surgery performed through a midline incision did not improve the respiratory function, whereas unilateral i.c.b. after surgery through a subcostal incision had positive effects. Thus postoperative i.c.b. following cholecystectomy performed through a subcostal incision resulted in higher FVC, FEV1 and PEF values than without i.c.b. at least during the time of effective nerve block. I.c.b. after subcostal incision also improved arterial oxygen tension. The patients undergoing cholecystectomy and receiving a second i.c.b. 8 h after the first one had better respiratory function than the patients without any block during the first 2 days postoperatively.

Factors influencing the respiratory capacity after upper abdominal surgery

The analgesic requirement and some factors influencing the respiratory capacity after upper abdominal surgery were studied during the first 2 days postoperatively in 417 patients, aged 17 to 84 years, undergoing surgery in the upper part of the abdomen. The operations were cholecystectomy or choledocholithotomy through a subcostal incision, partial gastric resection, repair of a diaphragmatic hernia or vagotomy through a midline incision. Pain relief was achieved in a random order either by intercostal block (i.c.b.) and centrally acting analgesics on demand, or by centrally acting analgesics alone. The analgesic demand was recorded, and the respiratory capacity was monitored by the peak expiratory flow rate (PEF). A smaller analgesic requirement and a smaller change in PEF were found after cholecystectomy than after any other kind of surgery. The demand for analgesics was age-dependent, and patients under 60 years of age demanded more than those aged 60 years and older. Bilateral i.c.b. given after surgery through a midline incision had few advantages, but unilateral i.c.b. following cholecystectomy and choledocholithotomy with a subcostal incision had positive effects. Thus it decreased the demand for centrally acting analgesics and resulted in higher PEF values than without i.c.b. for cholecystectomy during the period of effective nerve block and for choledocholithotomy for 2 whole days postoperatively. Smokers seemed to benefit from i.c.b. for 2 postoperative days. The reduction of PEF after cholecystectomy also seemed to be related to the duration of treatment with centrally acting analgesics.

Effects of intercostal nerve blocks on pulmonary mechanics in healthy men

Bilateral block of the 5th through the 11th intercostal nerves was induced in 16 healthy men. In eight of the men, bupivacaine 0.25% was used and in the other eight, etidocaine 0.5%. Before and after induction of the block flow/volume curves, maximal airway pressures, and pulmonary compliance, were recorded, and helium spirometry and multiple and single breath nitrogen wash-outs were performed. There were no differences between the results in the two groups, and the material was therefore pooled. Total lung capacity was decreased by 4%. There was no increase in residual volume, though the maximal expiratory airway pressure decreased by 7%. There was an 8% decrease in functional residual capacity. Pulmonary recoil appeared to be unchanged, as also did the effort-independent peak expiratory flow rates. According to the pulmonary nitrogen clearance index, the overall pulmonary time constant did not alter, while the slope of the alveolar plateau in the single breath nitrogen wash-out test increased by 9%. The significance of the latter finding is unclear, but it is concluded that the nerve block had no obvious effects on pulmonary mechanics, the changes observed rather being attributable to effects on the chest wall.