Effect of post-operative analgesia on patient morbidity

Extensive Spinal Epidural Abscess Associated with an Unremarkable Recovery

Spinal epidural abscess is a rare complication of epidural catheter insertion, with an incidence reported to be as low as 0.02%, but with a high morbidity and mortality. This reflects the difficulty in diagnosis of the condition, as early symptoms and signs are usually non-specific with late neurological manifestations. We report a case of spinal epidural abscess in a diabetic patient who underwent splenectomy and distal pancreatectomy. Early investigation with magnetic resonance imaging was effective in demonstrating an extensive epidural abscess involving the thoracic spine, with extension to the base of the skull and associated cord compression. Extensive multilevel laminectomies with thorough irrigation and washout of the epidural space were successful in treating this patient and preventing the development of permanent neurological sequelae.

Deep Tissue Incision Enhances Spinal Dorsal Horn Neuron Activity During Static Isometric Muscle Contraction in Rats

Translational correlates to pain with activities after deep tissue injury have been rarely studied. We hypothesized that deep tissue incision causes greater activation of nociception-transmitting neurons evoked by muscle contraction. In vivo neuronal activity was recorded in 203 dorsal horn neurons (DHNs) from 97 rats after sham, skin-only, or skin + deep muscle incision. We evaluated DHN responses to static, isometric muscle contractions induced by direct electrical stimulation of the muscle. The effect of pancuronium on DHN response to contractions was also examined. Approximately 50% of DHNs with receptive fields in the hindpaw were excited during muscle contraction. One-second .5- and 1.0-g muscle contractions produced greater DHN activity after skin + deep muscle incision (median [interquartile range], 32 [5-39] impulses, P = .021; and 36 [26-46] impulses, P = .006, respectively) than after sham (6 [0-21] and 15 [8-32] impulses, respectively). Neuromuscular blockade with pancuronium inhibited the muscle contractions and DHN activation during electrical stimulation, demonstrating contraction-induced activation. The greater response of spinal DHNs to static muscle contraction after skin + deep muscle incision may model and inform mechanisms of dynamic pain after surgery. PERSPECTIVE: Completion of various activities is an important milestone for recovery and hospital discharge after surgery. Skin + deep muscle incision caused greater activation of nociception-transmitting DHNs evoked by muscle contraction compared with skin-only incision. This result suggests an important contribution of deep muscle injury to activity-evoked hyperalgesia after surgery.

Low-dose subcutaneous ketamine for postoperative pain management in Rwanda: a dose-finding study

PURPOSE

Good pain control is not a normal part of surgical care in sub-Saharan Africa due to lack of resources. The primary objective of this study was to determine an efficacious dose of subcutaneous ketamine for postoperative pain for use in a future randomized controlled trial.

METHODS

Following research ethics board and local hospital approval for this research, we obtained informed consent from 31 patients undergoing major surgery for a random walk dose-finding study. In addition to standard postoperative care, participants received five doses of subcutaneous ketamine at scheduled intervals from arrival in the postanesthesia care unit (PACU) to postoperative day 2. Participants received 50 mg of ketamine (minimum 0.6 to maximum 1.1 mg·kg^-1, based on different body weights) for the first and second dose, with subsequent doses adjusted by 10 mg according to pain and side effects. Pain scores were recorded at rest and with movement.

RESULTS

The following mean (standard deviation [SD]) pain scores at rest and with movement were recorded on arrival in the PACU and on the afternoon of postoperative days 1 and 2: [at rest: 8.2 (1.5), 3.2 (1.8), and 0.7 (1.0), respectively; with movement: 9.4 (0.8), 5.1 (1.7), and 2.4 (1.1), respectively]. This rate of improvement suggests possible pain relief through use of ketamine. The mean (SD) ketamine dose that appeared efficacious in pain reduction was 0.90 (0.23) mg·kg^-1. There were no serious side effects.

CONCLUSION

Adding subcutaneous ketamine to standard analgesic measures resulted in decreases in postoperative pain scores without serious side effects. These data can be used to inform a randomized controlled trial to compare subcutaneous ketamine plus standard care with placebo plus standard care for reducing postoperative pain.

Perioperative multimodal anesthesia using regional techniques in the aging surgical patient

Background. Elderly patients have unique age-related comorbidities that may lead to an increase in postoperative complications involving neurological, pulmonary, cardiac, and endocrine systems. There has been an increase in the number of elderly patients undergoing surgery as this portion of the population is increasing in numbers. Despite advances in perioperative anesthesia and analgesia along with improved delivery systems, monotherapy with opioids continues to be the mainstay for treatment of postop pain. Reliance on only opioids can oftentimes lead to inadequate pain control or increase in the incidence of adverse events. Multimodal analgesia incorporating regional anesthesia is a promising alternative that may reduce needs for high doses and dependence on opioids along with any potential associated adverse effects. Methods. The following databases were searched for relevant published trials: Cochrane Central Register of Controlled Trials and PubMed. Textbooks and meeting supplements were also utilized. The authors assessed trial quality and extracted data. Conclusions. Multimodal drug therapy and perioperative regional techniques can be very effective to perioperative pain management in the elderly. Regional anesthesia as part of multimodal perioperative treatment can often reduce postoperative neurological, pulmonary, cardiac, and endocrine complications. Regional anesthesia/analgesia has not been proven to improve long-term morbidity but does benefit immediate postoperative pain control. In addition, multimodal drug therapy utilizes a variety of nonopioid analgesic medications in order to minimize dosages and adverse effects from opioids while maximizing analgesic effect and benefit.

Postoperative pain trajectories in cardiac surgery patients

Poorly controlled postoperative pain is a longstanding and costly problem in medicine. The purposes of this study were to characterize the acute pain trajectories over the first four postoperative days in 83 cardiac surgery patients with a mixed effects model of linear growth to determine whether statistically significant individual differences exist in these pain trajectories, and to compare the quality of measurement by trajectory with conventional pain measurement practices. The data conformed to a linear model that provided slope (rate of change) as a basis for comparing patients. Slopes varied significantly across patients, indicating that the direction and rate of change in pain during the first four days of recovery from surgery differed systematically across individuals. Of the 83 patients, 24 had decreasing pain after surgery, 24 had increasing pain, and the remaining 35 had approximately constant levels of pain over the four postoperative days.

Prospective, randomized, controlled trial of thoracic epidural or patient-controlled opiate analgesia on perioperative quality of life

BACKGROUND

Perioperative epidural analgesia provides continuous pain control and may have advantages over parenteral opiate administration. This study assessed the impact of epidural analgesia on quality of life (QOL) of patients undergoing major surgery.

METHODS

Sixty patients undergoing thoracic or thoraco-abdominal surgery were studied prospectively. Patients were randomly assigned to receive either thoracic epidural analgesia or patient-controlled i.v. opiate analgesia (PCA) after operation. Visual analogue pain and sedation scores were recorded for the period of the study. QOL health surveys at 24 h (SF-8 acute form) and at 1 week (SF-36) were recorded. Results were examined by uni- and multivariate analyses corrected for the effect of multiple comparisons.

RESULTS

Mean pain scores were significantly lower in the epidural group at most time points. Physical and mental scores in the epidural group were significantly better than the PCA group for both SF-8 and SF-36 QOL health surveys (P<0.001).

CONCLUSIONS

Epidural analgesia with local anaesthetic and opioid improves QOL and delivers better analgesia compared with PCA in patients undergoing major thoraco-abdominal surgery.

A controlled comparison between single doses of intravenous and intramuscular morphine with respect to analgesic effects and patient safety

BACKGROUND AND AIM OF INVESTIGATION: Intramuscular (IM) administration has been considered to be safer than intravenous (IV) for opioids on wards, but a comparative knowledge of patient safety and analgesic potency following a single dose of IV and IM administration is lacking. This study was carried out to compare patient safety and analgesic efficacy of a single and high dose of morphine given IM or IV for post-operative pain management.

MATERIALS AND METHODS

Thirty-eight patients with post-operative pain following hip replacement surgery were given IM or IV morphine 10 mg at a specified pain level. The study was randomized and double blinded. Time to onset of analgesic effect (11-point numeric rating scale), respiratory function (p(a)CO2, p(a)O2, and respiratory rate), level of sedation (5-point verbal rating scale), and hemodynamic function were recorded.

RESULTS

In the IV group there was a slight but significant increase in p(a)CO2 after 5, 10, and 15 min compared with the IM group (5.2 vs. 4.8, 5.4, vs. 5.0 and 5.5 vs. 5.1 kPa, respectively). The IV group had a significantly faster onset of analgesic effect than the IM group (5 vs. 20 min). Between 5 and 25 min after morphine administration, pain status in the IV group was significantly improved compared with the IM group. Patients in the IV group were slightly more sedated than the IM group 5 and 10 min after morphine.

CONCLUSION

A 10 mg bolus dose of IV morphine given to patients with moderate pain after surgery does not cause severe respiratory depression, but provides more rapid and better initial analgesia than 10 mg given IM. IV morphine even at a dose as high as 10 mg IV is well tolerated if there is a certain level of pain at its administration. The safety of IV morphine on the general ward needs to be further explored in adequately controlled studies.