Nathalie Bernard

Continuous peripheral nerve blocks in hospital wards after orthopedic surgery: a multicenter prospective analysis of the quality of postoperative analgesia and complications in 1,416 patients.

Background:Continuous peripheral nerve block (CPNB) is the technique of choice for postoperative analgesia after painful orthopedic surgery. However, the incidence of neurologic and infectious adverse events in the postoperative period are not well established. This issue was the aim of the study. Methods:Patients scheduled to undergo orthopedic surgery performed with a CPNB were prospectively included during 1 yr in a multicenter study. Efficacy of postoperative analgesia, bacteriologic cultures of the catheter, and acute neurologic and infectious adverse events were evaluated after surgery in 1,416 patients at arrival in the postanesthesia care unit, at hour 1, and every 24 h up to day 5. Risk factors for adverse events were determined using logistic regression. Results:The median duration of CPNB was 56 h. Both general anesthesia and CPNB were performed in 73.6% of the patients. Postoperative analgesia was effective in 96.3%, but an increase in pain scores was noted at hour 24 (P = 0.01). Hypoesthesia or numbness occurred in 3% and 2.2%, respectively, and paresthesia occurred in 1.5%. Three neural lesions (0.21%) were noted after continuous femoral nerve block. Two of these patients were anesthetized during block procedure. Nerve damage completely resolved 36 h to 10 weeks later. Cultures from 28.7% of the catheters were positive. Three percent of patients had local inflammatory signs. The bacterial species most frequently found were coagulase-negative staphylococcus (61%) and gram-negative bacillus (21.6%). A Staphylococcus aureus psoas abscess (0.07%) was reported in one diabetic woman. Independent risk factors for paresthesia/dysesthesia were postoperative monitoring in intensive care, age less than 40 yr, and use of bupivacaine. Risk factors for local inflammation/infection were postoperative monitoring in intensive care, catheter duration greater than 48 h, male sex, and absence of antibiotic prophylaxis. Conclusion:CPNB is an effective technique for postoperative analgesia. Minor incidents and bacterial colonization of catheters are frequent, with no adverse clinical consequences in the large majority of cases. Major neurologic and infectious adverse events are rare.

Continuous three-in-one block for postoperative pain after lower limb orthopedic surgery: where do the catheters go?

Continuous three-in-one block is widely used for postoperative analgesia after proximal lower limb surgery, but location of the catheter has not been well addressed in the literature. We prospectively studied, in 100 patients, the characteristics of catheter threading under the iliac fascia and the correlations between catheter tip location and effective sensory and motor blockade of the three principal nerves of the lumbar plexus. Postoperatively, in conscious patients, 16 to 20 cm of a catheter was placed in the fascial sheath after femoral nerve location with a nerve stimulator. Contrast media (3 mL Iopamidol 390®) was injected, and the catheter tip was located by means of an anteroposterior pelvic radiograph. An equal-volume mixture of 0.5% bupivacaine/2% lidocaine with epinephrine (30 mL) was injected through the catheter. Patient and catheter-insertion characteristics were noted. Thirty minutes after injection, sensory blockade was evaluated in the cutaneous territories of the lateral femoral cutaneous, femoral, and obturator nerves, along with motor blockade of the last two nerves. Pain scores at 30 min were also recorded. Seven block failures were noted. The tip of the catheter reached the lumbar plexus (Group 1) in 23% of the patients and lay deep to the medial (Group 2) or lateral (Group 3) part of the fascia iliaca in 33% and 37% of the patients, respectively. Demographic data and catheter threading characteristics were comparable among the groups. A three-in-one block was noted in 91% of Group 1 patients, but in only 52% and 27% of Group 2 and 3 patients, respectively (P < 0.05). Comparing Group 2 and 3 patients, sensory block was achieved in respectively 100% and 94% for the femoral nerve, 52% and 94% for the lateral femoral cutaneous nerve (P < 0.05), and 82% and 27% for the obturator nerve (P < 0.05). Visual analog scale pain scores on movement were significantly lower in Group 1 patients (P < 0.05). We conclude that during a continuous three-in-one block, the threaded catheter rarely reached the lumbar plexus. The quality of sensory and motor blockade and initial pain relief depend on the location of the catheter tip under the fascia iliaca.

Fascia iliaca compartment block for femoral bone fractures in prehospital care.

Background and Objectives The fascia iliaca compartment block provides a faster and more consistent simultaneous blockade of the lateral cutaneous and femoral nerves than the “3 in 1” block. We studied the effectiveness of this technique for analgesia after a femoral bone fracture in pre-hospital care. Methods Patients with an isolated femoral shaft fracture were included. A fascia iliaca compartment block was performed on all of them. Twenty milliliters of lidocaine 1.5 % with epinephrine were injected under the fascia iliaca. The intensity of pain was measured using a simplified verbal scale (SVS) from 0 (no pain) to 4 (extreme pain). The SVS was noted before the block was performed, 10 minutes later, and then on admission to the trauma care center. Sensory blockade was evaluated using cold perception in the lateral, medial, and internal part of the thigh 10 minutes after block performance and on arrival at the trauma care center. Results Twenty-seven patients were enrolled in this study. The SVS was 3 (3-4) before the block, 1 (0-2) 10 minutes after the block, and 0 (0-1) when arriving at the trauma care center (P < .05). The SVS was lower when the internal part of the thigh was blocked. Conclusion The fascia iliaca compartment block is a simple, inexpensive, and effective method of prehospital analgesia for femoral shaft fracture. A sensory block of the internal part of the thigh is an early predictive sign of optimal pain relief.

Patient-controlled perineural analgesia after ambulatory orthopedic surgery: A comparison of electronic versus elastomeric pumps

P ostoperative pain is a major challenge in the practice of anesthesia for ambulatory orthopedic surgery (1–3). Despite the use of long-acting local anesthesia in peripheral nerve blocks (PNB), 11% of patients report wound pain during the first 24 or 48 postoperative hours, and 17% to 22% of patients require opioid analgesics 7 days after surgery (1,4). Pain is a common reason for delayed discharge (5) and unanticipated hospital readmission. Orthopedic patients are the largest group who undergo PNB (6). PNB provide excellent anesthesia but also optimize postoperative analgesia, decrease hospital stay, and reduce the rate of unanticipated hospital readmission and probably health care costs as well (7,8). Recently, bolus injection (9), continuous infusion (10,11), and patient-controlled perineural administration (PCPA) (12–15) of local anesthetics at home after ambulatory orthopedic surgery have been described. Prospective studies will be required to compare efficacy and evaluate adverse events related to PCPA devices. This prospective, randomized study compared the efficacy of three pumps that are different in their deployment, adjustments, and ergonomics, available for postoperative analgesia.

Comparison of continuous 3-in-1 and fascia Iliaca compartment blocks for postoperative analgesia: feasibility, catheter migration, distribution of sensory block, and analgesic efficacy.

Background and Objectives Efficacy and technical aspects of continuous 3-in-1 and fascia iliaca compartment blocks were compared. Methods Forty-four patients scheduled for cruciate ligament repair or femur surgery were randomly divided into 2 groups. After surgery with the patient anesthetized, catheters were placed for continuous 3-in-1 blocks by means of a nerve stimulator (group 1). In group 2, the catheter was inserted for continuous fascia iliaca compartment block without the use of a nerve stimulator. In both groups, a 5-mg/kg bolus of 0.5% ropivacaine was administered followed by continuous infusion of 0.1 mL/kg/h of 0.2% ropivacaine for 48 hours. In the postoperative period, all the patients received parenteral propacetamol (6 g daily) and ketoprofen (200 mg daily) and 0.1 mg/kg of subcutaneous morphine as rescue analgesia if the visual analog scale (VAS) pain values were greater than 30 mm. We evaluated the technical difficulties relative to catheter placement, the location of the catheter, the analgesic efficacy, and the distribution of the sensory block at 1 hour, 24 hours, and 48 hours. Results Catheter placement was faster in group 2, and the absence of nerve stimulation decreased material costs (P < .05). No significant difference was observed between groups concerning location of the catheter tip under the fascia iliaca. In both groups, the distribution of the sensory block and its course were similar except for those of the obturator nerve (more sensory blocks in group 1, P < .05). No significant difference was noted between the groups regarding median VAS pain values and consumption of morphine during the 48-hour period. No major side effect was observed. Conclusions The authors conclude that a catheter for continuous lumbar plexus block can be placed more quickly and at lesser cost using the fascia iliaca technique than the perivascular technique with equivalent postoperative analgesic efficacy.

Ultrasound-guided Evaluation of the Local Anesthetic Spread Parameters Required for a Rapid Surgical Popliteal Sciatic Nerve Block

Background: The ideal spread of local anesthetic (LA) solution around the sciatic nerve during a popliteal block remains unclear. We tested the hypothesis that a circumferential spread of LA and/or intraneural injection could lead to rapid surgical block. Methods: Patients (n = 100) scheduled for foot or ankle surgery underwent popliteal sciatic nerve block using nerve stimulation according to Borgeats technique and injection of ropivacaine (0.5 mL/kg). Sensory and motor blockades were assessed on the tibial nerve (TN) and common peroneal nerve (CPN) at 5, 15, and 30 mins after completion of the block and in the recovery room. A successful block was defined as a complete sensory block in TN and CPN. Changes in cross-sectional and longitudinal surfaces and diameters and the characteristics of LA spread around the nerve were noted using ultrasound. A suspected intraneural injection was defined as a 15% increase in the surface area or anteroposterior diameter of the nerve. Patients were followed up on days 1 and 7 after surgery. Results: Successful block was noted in 57% of patients at 30 mins and in 88% of patients in the recovery room. A circumferential spread of LA occurred in 47% of patients and 53% had noncircumferential spread. Complete sensory block was significantly higher in the group that had a circumferential spread (73% vs 43%, P = 0.035) only at 30 mins. In the postoperative care unit, there was no difference among the groups. Separated circumferential spreads around TN and CPN were noted in 12% of patients. All of these patients had a complete sensory and motor blockade at 15 mins. Concerning intraneural injection, only the change in the anteroposterior diameter on a 6-cm length of nerve was associated with a higher success and faster onset block at 5 (P = 0.008), 15 (P = 0.02), and 30 (P = 0.05) mins. There were no clinically detectable nerve injuries at follow-up. Conclusion: For popliteal sciatic nerve block, circumferential spread of LA, and separation of the nerve into its 2 components are associated with rapid surgical block.

Estimation and pharmacodynamic consequences of the minimum effective anesthetic volumes for median and ulnar nerve blocks: a randomized, double-blind, controlled comparison between ultrasound and nerve stimulation guidance.

BACKGROUND:Nerve stimulation and ultrasound guidance are the most popular techniques for peripheral nerve blocks. However, the minimum effective anesthetic volume (MEAV) in selected nerves for both techniques and the consequences of decreasing the local anesthetic volume on the pharmacodynamic characteristics of nerve block remain unstudied. We designed a randomized, double-blind controlled comparison between neurostimulation and ultrasound guidance to estimate the MEAV of 1.5% mepivacaine and pharmacodynamics in median and ulnar nerve blocks. METHODS:Patients scheduled for carpal tunnel release were randomized to ultrasound guidance (UG) or neurostimulation (NS) groups. A step-up/step-down study model (Dixon method) was used to determine the MEAV with nonprobability sequential dosing based on the outcome of the previous patient. The starting dose of 1.5% mepivacaine was 13 and 11 mL for median and ulnar nerves at the humeral canal. Block success/failure resulted in a decrease/increase of 2 mL. A blinded physician assessed sensory blockade at 2-minute intervals for 20 minutes. Block onset time and duration were noted. RESULTS:The MEAV50 (SD) of the median nerve was lower in the UG group 2 (0.1) mL (95% confidence interval [CI] = [1, 96] to [2, 04]) than in the NS group 4 (3.8) mL (95% CI = [2, 4] to [5, 6]) (P = 0.017). There was no difference for the ulnar nerve between UG group 2 (0.1) mL (95% CI = [1, 96] to [2, 04]) and NS group 2.4 (0.6) mL (95% CI = [2, 1] to [2, 7]). The duration of sensory blockade was significantly correlated to local anesthetic volume, but onset time was not modified. CONCLUSION:Ultrasound guidance selectively provided a 50% reduction in the MEAV of mepivacaine 1.5% for median nerve sensory blockade in comparison with neurostimulation. Decreasing the local anesthetic volume can decrease sensory block duration but not onset time.

The ultrasound-guided transversus abdominis plane block for anterior iliac crest bone graft postoperative pain relief: a prospective descriptive study.

Background: Acute postoperative pain and nerve injuries frequently lead to neuropathic chronic pain after anterior iliac crest (AIC) bone graft. This prospective study evaluated postoperative pain relief after preoperative ultrasound-guided transversus abdominis plane (TAP) block for orthopedic surgery with an AIC bone harvest and the prevalence of pain chronicization at 18 months after surgery. Methods: Thirty-three consecutive patients scheduled for major orthopedic surgery with an AIC harvest for autologous bone graft were studied. Preoperative TAP blocks were performed under in-plane needle ultrasound guidance, anterior to the midaxillary line (15 mL ropivacaine 0.33%). The extent of sensory blockade was evaluated at 20 mins with cold and light-touch tests. Pain at the iliac crest graft site was assessed at rest by visual analog scale (VAS) scores in the postanesthetic care unit, and at 1, 6, 12, 24, and 48 hrs after surgery. Time for first request of morphine and total morphine consumption were recorded. Eighteen months after surgery, each patient was interviewed by phone about the importance and localization of pain chronicization. Results: Median VAS score was 0 (range, 0-7) at all periods of assessment. At 20 mins, 62.5% of the patients reported complete anesthesia, and 34% hypoesthesia. The sensory blockade extent ranged from T9 (T7-T11) to L1 (T11-L2) in median (range) values. At 18 months, 80% of patients did not complain about pain or discomfort at the iliac crest site; 20% reported pain chronicization at the iliac crest site (VAS scores 2-4). Five patients (26%) complained about numbness at the iliac crest area. Conclusions: Ultrasound-guided TAP block is an appropriate technique for postoperative analgesia after AIC bone harvest in orthopedic surgery.

Hemodynamic profile of target-controlled spinal anesthesia compared with 2 target-controlled general anesthesia techniques in elderly patients with cardiac comorbidities.

Background and Objectives The impact of anesthesia techniques in patients experiencing hip fracture is controversial. This study compares the effects on blood pressure of 3 anesthesia techniques that are considered safe for the elderly. Methods Forty-five patients older than 75 years, with American Society of Anesthesiologists physical status III or IV, with cardiac comorbidities, and undergoing surgery for hip fracture, were randomized to receive continuous spinal anesthesia (CSA), propofol target-controlled infusion (TCI), or sevoflurane (SEVO). In CSA patients, a T10 metameric level target was achieved by titration of 2.5 mg of bupivacaine boluses. In patients on TCI and SEVO, a bispectral value target of around 50 guided the concentration of propofol or sevoflurane. Analgesia in the TCI and SEVO groups was provided with remifentanil. Hypotension was defined as a 30% decrease in mean arterial pressure and was treated with an intravenous bolus of ephedrine. Results The number of hypotension episodes was lower in the CSA group: 0 (range, 0–6) versus 11.5 (range, 1–25) in the TCI group and 10 (range, 1–23) in the SEVO group (P < 0.001). Both TCI and SEVO patients needed more ephedrine compared with CSA patients (30.5 [15.5], 26 [23], and 1.5 [2.5] mg, respectively, P < 0.001). The maximal decrease in mean arterial pressure was lower in the CSA group (26% [17%]) compared with that in the TCI group (47% [8%]) and the SEVO group (46% [12%]; P < 0.001). Conclusions In elderly patients, spinal anesthesia using titrated doses of bupivacaine provided better blood pressure stability than propofol or sevoflurane anesthesia.

Percutaneous electrode guidance using the insulated needle for prelocation of peripheral nerves during axillary plexus blocks

Background and Objectives: Short reports have noted that percutaneous prelocation is helpful in determining the anatomic course of a peripheral nerve, and, thereby, may serve as a guide for block needle insertion. We prospectively studied percutaneous electrode guidance to assist axillary brachial plexus blocks. Methods: In 131 consecutive patients, the tip of an insulated needle emitting 5 mA was placed on the skin above and below the axillary artery to obtain a hand motor response characteristic of the median, ulnar, and radial nerves in succession. The current was reduced until all movement had ceased. The needle was then inserted toward the nerve to be blocked, decreasing the intensity from 2 mA to 0.5 mA, so that the same selected motor response was still obtained. The length of the needle inserted was noted, and 1.5% lidocaine was injected. Pain verbal analogic score (VAS) values were noted during both procedures. Complete sensory blockade was evaluated at 30 min. Results: Rates of successful percutaneous electrode guidance were 94.6% for the median nerve, 89.4% for the radial nerve, 88.5% for the ulnar nerve, and 85.5% for all 3 nerves together. A significant correlation was found between the lowest percutaneous current applied and the depth of the nerve stimulated at 0.5 mA. Pain VAS values were significantly lower during percutaneous stimulation than during needle insertion (P < .05). Sensory block for all 3 nerves was noted in 92% of patients. Conclusions: Percutaneous electrode guidance using the insulated needle enabled clinicians to locate the terminal branches of the plexus in the axilla and appreciate their depth. This method could, therefore, minimize patient discomfort and perhaps the risk of nerve trauma.