Sakura Kinjo

Does Preoperative Risk for Delirium Moderate the Effects of Postoperative Pain and Opiate Use on Postoperative Delirium

OBJECTIVES To investigate whether preoperative risk for delirium moderates the effect of postoperative pain and opioids on the development of postoperative delirium. DESIGN Prospective cohort study. SETTING University medical center. PARTICIPANTS Patients 65 years of age or older scheduled for major noncardiac surgery. MEASUREMENTS A structured interview was conducted preoperatively and postoperatively to determine the presence of delirium, defined using the Confusion Assessment Method. We first developed a prediction model to determine which patients were at high versus low risk for the development of delirium based on preoperative patient data. We then computed a logistic regression model to determine whether preoperative risk for delirium moderates the effect of postoperative pain and opioids on incident delirium. RESULTS Of 581 patients, 40% developed delirium on days 1 or 2 after surgery. Independent preoperative predictors of postoperative delirium included lower cognitive status, a history of central nervous system disease, high surgical risk, and major spine and joint arthroplasty surgery. Compared with the patients at low preoperative risk for developing delirium, the relative risk for postoperative delirium for those in the high preoperative risk group was 2.38 (95% confidence interval: 1.67-3.40). A significant three-way interaction indicates that preoperative risk for delirium significantly moderated the effect of postoperative pain and opioid use on the development of delirium. Among patients at high preoperative risk for development of delirium who also had high postoperative pain and received high opioid doses, the incidence of delirium was 72%, compared with 20% among patients with low preoperative risk, low postoperative pain, and those who received low opioid doses. CONCLUSIONS High levels of postoperative pain and using high opioid doses increased risk for postoperative delirium for all patients. The highest incidence of delirium was among patients who had high preoperative risk for delirium and also had high postoperative pain and used high opioid doses.

Does Postoperative Delirium Limit the Use of Patient-controlled Analgesia in Older Surgical Patients?

Background:Postoperative pain Is an independent predictor of postoperative delirium. Whether postoperative delirium limits patient-controlled analgesia (PCA) use has not been determined. Methods:The authors conducted a nested cohort study in older patients undergoing noncardiac surgery and used PCA for postoperative analgesia. Delirium was measured by using the Confusion Assessment Method. The authors computed a structural equation model to determine the effects of pain and opioid consumption on delirium status and the effect of delirium on opioid use. Results:Of 335 patients, 108 (32.2%) developed delirium on postoperative day (POD) 1, and 120 (35.8%) on POD 2. Postoperative delirium did not limit the use of PCA. Patients with postoperative delirium used more PCA in a 24-h period (POD 2) compared to those without delirium (mean dose of hydromorphone ± SE adjusted for covariates was 2.24 ± 0.71 mg vs. 1.25 ± 0.67 mg, P = 0.02). Despite more opioid use, patients with delirium reported higher Visual Analogue Scale scores than those without delirium (POD 1: mean visual analog scale ± SE at rest 4.2 ± 0.23 vs. 3.3 ± 0.22, P = 0.0051; POD 2: 3.3 ± 0.23 vs. 2.5 ± 0.19, P = 0.004). Path coefficients from structural equation model revealed that pain and opioid use affect delirium status, but delirium does not affect subsequent opioid dose. Conclusions:Postoperative delirium did not limit PCA use. Despite more opioid use, visual analog scale scores were higher in patients with delirium. Future studies on delirium should consider the role of pain and pain management as potential etiologic factors.

Does using a femoral nerve block for total knee replacement decrease postoperative delirium

BackgroundThe effect of peripheral nerve blocks on postoperative delirium in older patients has not been studied. Peripheral nerve blocks may reduce the incidence of postoperative opioid use and its side effects such as delirium via opioid-sparing effect.MethodsA prospective cohort study was conducted in patients who underwent total knee replacement. Baseline cognitive function was assessed using the Telephone Interview for Cognitive Status. Postoperative delirium was measured using the Confusion Assessment Method postoperatively. Incidence of postoperative delirium was compared in two postoperative management groups: femoral nerve block ± patient-controlled analgesia and patient-controlled analgesia only. In addition, pain levels (using numeric rating scales) and opioid use were compared in two groups.Results85 patients were studied. The overall incidence of postoperative delirium either on postoperative day one or day two was 48.1%. Incidence of postoperative delirium in the femoral nerve block group was lower than patient controlled analgesia only group (25% vs. 61%, P = 0.002). However, there was no significant difference between the groups with respect to postoperative pain level or the amount of intravenous opioid use.ConclusionsFemoral nerve block reduces the incidence of postoperative delirium. These results suggest that a larger randomized control trial is necessary to confirm these preliminary findings.

Failure of supraclavicular block under ultrasound guidance: clinical relevance of anatomical variation of cervical vessels

We describe a case with partial analgesia after ultrasound-guided supraclavicular block for elbow surgery. The failure of the block was caused by the limited spread of local anesthetic because of blockage by a vessel (either transverse cervical artery or dorsal scapular artery) running through the brachial plexus. Anesthesiologists should be aware that cervical anatomy is complex and has anatomical variations. Thus, careful ultrasound screening of anatomical structure, especially using color Doppler, is important in performing brachial plexus block.

A survey of education and confidence level among graduating anesthesia residents with regard to selected peripheral nerve blocks.

BackgroundAs peripheral nerve blockade has increased significantly over the past decade, resident education and exposure to peripheral nerve blocks has also increased. This survey assessed the levels of exposure and confidence that graduating residents have with performing selected peripheral nerve blocks.MethodsAll program directors of ACGME-accredited anesthesiology programs in the USA were asked to distribute an online survey to their graduating residents. Information was gathered on the number and types of nerve blocks performed, technique(s) utilized, perceived comfort level in performing nerve blocks, perceived quality of regional anesthesia teaching during residency, and suggested areas for improvement.ResultsOne hundred and seven residents completed the survey. The majority completed more than 60 nerve blocks. Femoral and interscalene blocks were performed most frequently, with 59% and 41% of residents performing more than 20 of each procedure, respectively. The least-performed block was the lumber plexus block, with just 9% performing 20 or more blocks. Most residents reported feeling “very” to “somewhat” comfortable performing the surveyed blocks, with the exception of the lumber plexus block, where 64% were “not comfortable.” Overall, 78% of residents were “mostly” to “very satisfied” with the quality of education received during residency.ConclusionsMost of the respondents fulfilled the ACGME requirement and expressed satisfaction with the peripheral nerve block education received during residency. However, the ACGME requirement for 40 nerve blocks may not be adequate for some residents to feel comfortable in performing a full range of blocks upon graduation. Many residents felt that curriculums incorporating simulator training and didactic lectures would be the most helpful method of improving the quality of their education pertaining to peripheral nerve blocks.

Intrathecal morphine, but not buprenorphine or pentazocine, can induce spastic paraparesis after a noninjurious interval of spinal cord ischemia in the rat.

In this study, we sought to determine the effect of intrathecal (IT) pentazocine or buprenorphine on the neurological outcome after a short interval of spinal cord ischemia in rats. Although IT morphine (30 &mgr;g) induced spastic paraparesis after 6 min of aortic occlusion, neither pentazocine (150 &mgr;g) nor buprenorphine (4 &mgr;g) produced neurological dysfunction. Our results indicate that the effect of various opioids on the motor function after a noninjurious interval of spinal cord ischemia is opioid-specific.

Combined preoperative femoral and sciatic nerve blockade improves analgesia after anterior cruciate ligament reconstruction: a randomized controlled clinical trial

STUDY OBJECTIVE To compare preoperative femoral (FNB) with combined femoral and sciatic nerve block (CFSNB) in patients undergoing arthroscopic anterior cruciate ligament (ACL) reconstruction. DESIGN Prospective, randomized clinical trial. SETTING Ambulatory surgery center affiliated with an academic medical center. PATIENTS Sixty-eight American Society of Anesthesiology physical status I and II patients undergoing arthroscopic ACL reconstruction. INTERVENTIONS Subjects randomized to the CFSNB group received combined femoral and sciatic nerve blocks preoperatively, whereas patients randomized to the FNB group only received femoral nerve block preoperatively. Both groups then received a standardized general anesthetic with a propofol induction followed by sevoflurane or desflurane maintenance. Intraoperative pain was treated with fentanyl. Pain in the postanesthesia care unit (PACU) was treated with ketorolac and opiates. Patients with significant pain despite ketorolac and opiates could receive a rescue nerve block. MEASUREMENTS Our primary outcome variable was highest Numeric Rating Scale (NRS) pain score in PACU. NRS pain scores, opioid consumption, opioid adverse effects, and patient satisfaction were assessed perioperatively until postoperative day 3. MAIN RESULTS The highest PACU NRS pain score was significantly higher in the FNB group compared with the CFSNB group (7 [3-10] vs 5 [0-10], P=.002). The FNB group required significantly larger doses of opioids perioperatively (31.8 vs 19.8mg intravenous morphine equivalents, P<.001). PACU length of stay was significantly longer in the FNB group (128.2 vs 103.1minutes, P=.006). There was no significant difference in opioid consumption, pain scores, or patient satisfaction on postoperative days 1-3 between groups. CONCLUSIONS Preoperative CFSNB for arthroscopic ACL reconstruction improves analgesia, decreases opioid consumption perioperatively, and decreases PACU length of stay when compared with FNB alone.

Perioperative Gabapentin Does Not Reduce Postoperative Delirium in Older Surgical Patients: A Randomized Clinical Trial

Background: Postoperative pain and opioid use are associated with postoperative delirium. We designed a single-center, randomized, placebo-controlled, parallel-arm, double-blinded trial to determine whether perioperative administration of gabapentin reduced postoperative delirium after noncardiac surgery. Methods: Patients were randomly assigned to receive placebo (N = 347) or gabapentin 900 mg (N = 350) administered preoperatively and for the first 3 postoperative days. The primary outcome was postoperative delirium as measured by the Confusion Assessment Method. Secondary outcomes were postoperative pain, opioid use, and length of hospital stay. Results: Data for 697 patients were included, with a mean ± SD age of 72 ± 6 yr. The overall incidence of postoperative delirium in any of the first 3 days was 22.4% (24.0% in the gabapentin and 20.8% in the placebo groups; the difference was 3.20%; 95% CI, 3.22% to 9.72%; P = 0.30). The incidence of delirium did not differ between the two groups when stratified by surgery type, anesthesia type, or preoperative risk status. Gabapentin was shown to be opioid sparing, with lower doses for the intervention group versus the control group. For example, the morphine equivalents for the gabapentin-treated group, median 6.7 mg (25th, 75th quartiles: 1.3, 20.0 mg), versus control group, median 6.7 mg (25th, 75th quartiles: 2.7, 24.8 mg), differed on the first postoperative day (P = 0.04). Conclusions: Although postoperative opioid use was reduced, perioperative administration of gabapentin did not result in a reduction of postoperative delirium or hospital length of stay.

Exacerbation of chronic pain after dental extractions in a patient with post-treatment Lyme disease syndrome

A subset of patients who had Lyme disease experience postinfectious signs or symptoms called post-treatment Lyme disease syndrome (PTLDS). PTLDS is a chronic condition including pain in joints and muscles, neurological symptoms including demyelinating diseases, peripheral neuropathy, headaches, sleep disturbances, fatigue, and cardiac conditions. We report a case of difficult acute pain management in a patient with PTLDS who underwent dental extractions and required admission to an intensive care unit for pain control.

Preoperative Fascia Iliaca Block Does Not Improve Analgesia after Arthroscopic Hip Surgery, but Causes Quadriceps Muscles WeaknessA Randomized, Double-blind Trial

What We Already Know about This TopicHip arthroscopy is a surgical procedure growing in popularityThe optimal approach to postoperative analgesia has not been identified What This Article Tells Us That Is NewThe addition of preoperative fascia iliaca block using ropivacaine to the intraarticular injection of ropivacaine did not improve early postoperative pain scoresThe fascia iliaca blocks also did not improve most secondary endpoints, although they did cause quadriceps weakness Background: Ambulatory hip arthroscopy is associated with postoperative pain routinely requiring opioid analgesia. The potential role of peripheral nerve blocks for pain control after hip arthroscopy is controversial. This trial investigated whether a preoperative fascia iliaca block improves postoperative analgesia. Methods: In a prospective, double-blinded trial, 80 patients scheduled for hip arthroscopy were randomized to receive a preoperative fascia iliaca block with 40 ml ropivacaine 0.2% or saline. Patients also received an intraarticular injection of 10-ml ropivacaine 0.2% at procedure end. Primary study endpoint was highest pain score reported in the recovery room; other study endpoints were pain scores and opioid use 24 h after surgery. Additionally, quadriceps strength was measured to identify leg weakness. Results: The analysis included 78 patients. Highest pain scores in the recovery room were similar in the block group (6 ± 2) versus placebo group (7 ± 2), difference: −0.2 (95% CI, −1.1 to 0.7), as was opioid use (intravenous morphine equivalent dose: 15 ± 7mg [block] vs. 16 ± 9 mg [placebo]). Once discharged home, patients experienced similar pain and opioid use (13 ± 7 mg [block] vs. 12 ± 8 mg [placebo]) in the 24 h after surgery. The fascia iliaca block resulted in noticeable quadriceps weakness. There were four postoperative falls in the block group versus one fall in the placebo group. Conclusions: Preoperative fascia iliaca blockade in addition to intraarticular local anesthetic injection did not improve pain control after hip arthroscopy but did result in quadriceps weakness, which may contribute to an increased fall risk. Routine use of this block cannot be recommended in this patient population.