Naloxegol and Postoperative Urinary Retention: A Randomized Trial.

BACKGROUND: Naloxegol antagonizes peripheral opioid-related side effects without preventing opioid-related analgesia. However, the effect of naloxegol on opioid-induced bladder dysfunction remains unknown. HYPOTHESIS: patients given naloxegol have lower residual bladder urine volume than those given placebo. METHODS: 136 patients scheduled for elective hip and knee surgery were randomized to oral naloxegol or placebo given the morning of surgery, and on the first two postoperative mornings. Residual urine volume was measured ultrasonographically within 30 min after voiding once in the morning and once in the afternoon for two postoperative days. Opioid-related Symptom Distress Scale (ORSDS), the need for indwelling urinary catheterization, and quality of recovery (QoR) score were secondary outcomes. RESULTS: 67 were randomized to naloxegol and 64 to placebo. We did not identify a significant effect on urine residual volume, with an estimated ratio of geometric means of 0.9 (0.3, 2.6), p = 0.84. There were no significant differences in ORSDS or QoR. There were 19 (29%) patients assigned to naloxegol who needed indwelling urination catheterization versus 7 (11%) patients in the placebo group, p = 0.012. CONCLUSIONS: Our results do not support use of naloxegol for postoperative urinary retention after hip and knee surgery.

Real-time ultrasound-guided spinal anesthesia in patients with predicted difficult anatomy.

BACKGROUND: There are limited reports of lumbar neuraxial blocks using real-time US in patients with predicted difficulties. We compared the number of attempts to perform spinal anesthesia using real-time US guidance versus landmark technique in patients meeting predefined criteria for difficult spinal anesthesia. We also compared procedure time, block success, patient satisfaction and difficulty scores between groups. METHODS: Following institutional review board approval patients scheduled for total hip or knee arthroplasty with expected difficulty to perform spinal anesthesia were included. Number of attempts, block time, success rate, patient satisfaction and difficulty scores were recorded and we conducted the Kruskal-Wallis non-parametric test of difference between the groups. RESULTS: Thirty-eight patients were enrolled and a total of 32 data sets was analyzed. For number of attempts, we observed no difference between the groups (P<0.83). The US group resulted in marginally higher time to block compared to the control (P<0.0653). The US group resulted in marginally higher satisfaction compared to the control group (P<0.09). The block success rate was 100% in both groups. Anesthesiologists rated the US group procedure more difficult than the control group (χ2=10.85, P<0.0010). CONCLUSIONS: This trial suggests that real-time US guidance for spinal anesthesia in challenging patients in comparison to the controlled group was completed in longer time, with lower needle insertion attempts, and higher patient satisfaction scores but without statistically significant differences.

The Cleveland Clinic experience with supraclavicular and popliteal ambulatory nerve catheters.

Continuous peripheral nerve blocks (CPNB) are commonly used for intraoperative and postoperative analgesia. Our study aimed at describing our experience with ambulatory peripheral nerve catheters. After Institutional Review Board approval, records for all patients discharged with supraclavicular or popliteal catheters between January 1, 2009 and December 31, 2011 were reviewed. A licensed practitioner provided verbal and written instructions to the patients prior to discharge. Daily follow-up phone calls were conducted. Patients either removed their catheters at home with real-time simultaneous telephone guidance by a member of the Acute Pain Service or had them removed by the surgeon during a regular office visit. The primary outcome of this analysis was the incidence of complications, categorized as pharmacologic, infectious, or other. The secondary outcome measure was the average daily pain score. Our study included a total of 1059 patients with ambulatory catheters (769 supraclavicular, 290 popliteal). The median infusion duration was 5 days for both groups. Forty-two possible complications were identified: 13 infectious, 23 pharmacologic, and 6 labeled as other. Two patients had retained catheters, 2 had catheter leakage, and 2 had shortness of breath. Our study showed that prolonged use of ambulatory catheters for a median period of 5 days did not lead to an increased incidence of complications.

Comparison of three techniques for ultrasound-guided femoral nerve catheter insertion: a randomized, blinded trial.

BACKGROUND: Ultrasound guidance for continuous femoral perineural catheters may be supplemented by electrical stimulation through a needle or through a stimulating catheter. The authors tested the primary hypothesis that ultrasound guidance alone is noninferior on both postoperative pain scores and opioid requirement and superior on at least one of the two. Second, the authors compared all interventions on insertion time and incremental cost. METHODS: Patients having knee arthroplasty with femoral nerve catheters were randomly assigned to catheter insertion guided by: (1) ultrasound alone (n = 147); (2) ultrasound and electrical stimulation through the needle (n = 152); or (3) ultrasound and electrical stimulation through both the needle and catheter (n = 138). Noninferiority between any two interventions was defined for pain as not more than 0.5 points worse on a 0 to 10 verbal response scale and for opioid consumption as not more than 25% greater than the mean. RESULTS: The stimulating needle group was significantly noninferior to the stimulating catheter group (difference [95% CI] in mean verbal response scale pain score [stimulating needle vs. stimulating catheter] of -0.16 [-0.61 to 0.29], P < 0.001; percentage difference in mean IV morphine equivalent dose of -5% [-25 to 21%], P = 0.002) and to ultrasound-only group (difference in mean verbal response scale pain score of -0.28 [-0.72 to 0.16], P < 0.001; percentage difference in mean IV morphine equivalent dose of -2% [-22 to 25%], P = 0.006). In addition, the use of ultrasound alone for femoral nerve catheter insertion was faster and cheaper than the other two methods. CONCLUSION: Ultrasound guidance alone without adding either stimulating needle or needle/catheter combination thus seems to be the best approach to femoral perineural catheters.

Dedicated orthopedic operating room unit improves operating room efficiency.

We investigated the effectiveness of dedicated orthopedic operating rooms (OR) on minimizing time spent on perioperative processes to increase OR throughput in total knee and hip arthroplasty procedures. The use of a dedicated orthopedic unit that included 6 ORs with staff allocated only for those ORs was compared to the use of a traditional staffing model. After matching to simulate randomization, each group consisted of 422 procedures. The dedicated orthopedic unit improved average anesthesia controlled time by 4 minutes (P<.001), operative time by 7 minutes (P=.004) and turnover time by 8 minutes (P<.001). An overall improvement of 19 minutes per procedure using the dedicated unit was observed. Utilizing a dedicated orthopedic unit can save time without increasing adverse events.

Acute respiratory distress following ultrasound-guided supraclavicular block.

BACKGROUND: Brachial plexus blocks have become very common for patients undergoing upper extremity surgery. We report a case in which the patient developed ipsilateral phrenic nerve paralysis and acute respiratory failure following supraclavicular nerve block. CASE REPORT: A 61-year-old female diabetic, morbidly obese patient presented for a repeat debridement of necrotizing fasciitis on her left arm. She received a left-sided supraclavicular brachial plexus block. Within a few minutes, the patient began to experience acute dyspnea, anxiety, and oxygen saturation of 90%. Breath sounds were diminished in the left hemithorax. Arterial blood gases revealed evidence of acute respiratory acidosis. The chest x-ray was normal. After induction, we intubated the patient. Subsequent arterial blood gases showed marked improvement in respiratory acidosis. We believed left phrenic nerve paralysis to be the cause of the distress. The patient was extubated in the surgical intensive care unit the following day, and infusion of ropivacaine 0.2% was started. The catheter was removed afterward secondary to its occlusion. CONCLUSION: Phrenic nerve injury leading to respiratory distress is a rare complication of supraclavicular brachial plexus block. Anesthesiologists should be ready for emergency intubation when performing this kind of block.

Continuous femoral nerve blocks: decreasing local anesthetic concentration to minimize quadriceps femoris weakness.

BACKGROUND: Whether decreasing the local anesthetic concentration during a continuous femoral nerve block results in less quadriceps weakness remains unknown. METHODS: Preoperatively, bilateral femoral perineural catheters were inserted in subjects undergoing bilateral knee arthroplasty (n = 36) at a single clinical center. Postoperatively, right-sided catheters were randomly assigned to receive perineural ropivacaine of either 0.1% (basal 12 ml/h; bolus 4 ml) or 0.4% (basal 3 ml/h; bolus 1 ml), with the left catheter receiving the alternative concentration/rate in an observer- and subject-masked fashion. The primary endpoint was the maximum voluntary isometric contraction of the quadriceps femoris muscles the morning of postoperative day 2. Equivalence of treatments would be concluded if the 95% CI for the difference fell within the interval -20%-20%. Secondary endpoints included active knee extension, passive knee flexion, tolerance to cutaneous electrical current applied over the distal quadriceps tendon, dynamic pain scores, opioid requirements, and ropivacaine consumption. RESULTS: Quadriceps maximum voluntary isometric contraction for limbs receiving 0.1% ropivacaine was a mean (SD) of 13 (8) N · m, versus 12 (8) N · m for limbs receiving 0.4% [intrasubject difference of 3 (40) percentage points; 95% CI -10-17; P = 0.63]. Because the 95% CI fell within prespecified tolerances, we conclude that the effect of the two concentrations were equivalent. Similarly, there were no statistically significant differences in secondary endpoints. CONCLUSIONS: For continuous femoral nerve blocks, we found no evidence that local anesthetic concentration and volume influence block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.

Bilateral brachial plexus home going catheters after digital amputation for patient with upper extremity digital gangrene.

UNLABELLED: Peripheral nerve catheter placement is used to control surgical pain. Performing bilateral brachial plexus block with catheters is not frequently performed; and in our case sending patient home with bilateral brachial plexus catheters has not been reported up to our knowledge. Our patient is a 57 years old male patient presented with bilateral upper extremity digital gangrene on digits 2 through 4 on both sides with no thumb involvement. The plan was to do the surgery under sequential axillary blocks. On the day of surgery a right axillary brachial plexus block was performed under ultrasound guidance using 20 ml of 0.75% ropivacaine. Patient was taken to the OR and the right fingers amputation was carried out under mild sedation without problems. Left axillary brachial plexus block was then done as the surgeon was closing the right side, two hours after the first block was performed. The left axillary block was done also under ultrasound using 20 ml of 2% mepivacaine. The brachial plexus blocks were performed in a sequential manner. Surgery was unremarkable, and patient was transferred to post anesthetic care unit in stable condition. Over that first postoperative night, the patient complained of severe pain at the surgical sites with minimal pain relief with parentral opioids. We placed bilateral brachial plexus catheters (right axillary and left infra-clavicular brachial plexus catheters). Ropivacaine 0.2% infusion was started at 7 ml per hour basal rate only with no boluses on each side. The patient was discharged home with the catheters in place after receiving the appropriate education. On discharge both catheters were connected to a single ON-Q (I-flow Corporation, Lake Forest, CA) ball pump with a 750 ml reservoir using a Y connection and were set to deliver a fixed rate of 7 ml for each catheter. The brachial plexus catheters were removed by the patient on day 5 after surgery without any difficulty. Patient's postoperative course was otherwise unremarkable. We concluded that home going catheters are very effective in pain control postoperatively and they shorten the period of hospital stay. KEYWORDS: Brachial plexus; Home going catheters; Post-operative pain.