An opioid-free anaesthetic using nerve blocks enhances rapid recovery after minor hand surgery in children.

BACKGROUND AND OBJECTIVE: The aim of this prospective randomized study was to evaluate the quality of analgesia, postoperative comfort and subsequent duration of hospitalization after distal hand surgery and peripheral nerve block at the wrist for paediatric outpatients. METHODS: Sixty consecutive ASA I or II children were randomly assigned to the following groups: in group B (block), intraoperative and postoperative analgesia was provided by peripheral nerve block; and in group O (opioids), intraoperative and postoperative analgesia was provided by intravenous opioids. The patients' age, sex and type of surgery were recorded as were the postoperative pain management and postoperative vomiting. Time to discharge from the recovery room, the postoperative ward and the time to discharge home were also noted. RESULTS: The two groups were similar with respect to age, sex, ASA physical status, weight, height and types of injuries. The incidence of postoperative pain (CHEOPS score >or=7) and the incidence of postoperative vomiting were significantly higher in group O than in group B: 26.6 versus 3.3%; P = 0.025, and 33.3 versus 6.6%; P = 0.011, respectively. The time before oral intake was significantly longer in group O than in group B [187 (75-265) min versus 60 (32-125) min, respectively, P = 0.0002]. The time to meet discharge home criteria was 277 (230-330) min in group O versus 210 (145-260) min in group B (P = 0.0039). CONCLUSION: The present study demonstrates for the first time that, after distal hand surgery in children, peripheral nerve block improves pain management, opioid analgesia-induced side effects and provides a shorter postoperative recovery time than systemic analgesia with opioids.

Retrospective analysis of the risk factors and pathogens associated with early-onset ventilator-associated pneumonia in surgical-ICU head-trauma patients.

BACKGROUND: Early-onset ventilator associated pneumonia (EOVAP) are frequent in head-trauma patients, but specific risk factors are poorly studied in this population. METHODS: We conducted a retrospective cohort study in a surgical intensive care unit. Consecutive severe head-trauma patients admitted from January 2000 to December 2002 were studied. Microorganisms, and risks factors for EOVAP were analyzed. RESULTS: During the 3-year period, 161 patients were studied; 21.1% of them developed an EOVAP. On univariate analysis 6 variables were associated with EOVAP: early enteral feeding, barbiturate use, immunosuppression, mean Simplified Acute Physiology Score 2, acute respiratory distress syndrome, and initial neurosurgery procedures. On multivariate analysis, enteral feeding >2000 Kcal before day 5 [odds ratio (OR): 0.33, 95% confidence interval (CI): 0.21-0.85] and initial neurosurgical procedure (OR: 0.36, 95% CI: 0.15-0.89) remained protective factors for EOVAP, whereas immunosuppression (OR: 7.15, 95% CI: 1.66-30.73) and barbiturate use (OR: 2.68, 95% CI: 1.06-6.80) remained risk factors for EOVAP. EOVAP was also significantly associated with a longer duration of mechanical ventilation (14.0 vs. 11.0 d, P=0.024), and a longer sedation duration (8.3 vs. 5.8 d P=0.005). Methicillin-susceptible Staphylococcus aureus was the most common pathogen involved in EOVAP (46%). CONCLUSIONS: We demonstrate for the first time that early enteral feeding is a protective factor for EOVAP, and this result could have clinical implications for the prevention of EOVAP after traumatic brain injury. This study also confirms that barbiturate use is an important risk factor of EOVAP whereas Methicillin-susceptible S. aureus was found to be the main pathogen involved in EOVAP.

Epidural analgesia after scoliosis surgery: electrophysiologic and clinical assessment of the effects of bupivacaine 0.125% plus morphine versus ropivacaine 0.2% plus morphine.

STUDY OBJECTIVE: To study the electrophysiologic and clinical effects of epidural morphine combined with either bupivacaine 0.125% or ropivacaine 0.2%. DESIGN: Comparative, randomized, double-blind study. SETTINGS: Intensive care unit and hospital ward of a university hospital. PATIENTS: 18 adult ASA physical status I and II patients with degenerative or idiopathic scoliosis, undergoing posterior spinal fusion with instrumentation. INTERVENTIONS: Patients received epidural administration of 10-mL bolus of either bupivacaine or ropivacaine followed by a 6-mL/h infusion for 48 hours of unlabeled local anesthetic. In all patients, epidural morphine 5 mg was added daily. MEASUREMENTS: Assessment was focused mainly on somatosensory cortical evoked potentials, soleus H-reflex, and F waves. These electrophysiologic data were recorded before and after epidural medications. Second, respiratory rate, Paco(2), visual analog score (VAS), and side effects such as postoperative nausea and vomiting (PONV), gastrointestinal (GI) transit delay, and urinary retention were noted. MAIN RESULTS: Bupivacaine 0.125% + morphine was given to 9 patients, and ropivacaine 0.2% + morphine was given to 9 other patients. H-reflex, F waves, and somatosensory cortical evoked potential recording remained unchanged across the time of assessment. Respiratory rate and Paco(2) values were normal. VASs were indifferently low at rest, but they were lower with bupivacaine than with ropivacaine on mobilization. The frequency of PONV was indifferently high. No altered GI transit or urinary retention was noted. CONCLUSION: After epidural administration during the study conditions, bupivacaine 0.125% and ropivacaine 0.2% combined with morphine allow for neurologic examination.

Is there any need for expanding the perineural space before catheter placement in continuous femoral nerve blocks?

BACKGROUND AND OBJECTIVE: There is debate regarding the benefit of perineural space expansion before catheter placement in continuous femoral nerve block. This question is addressed in this prospective, comparative, and randomized study. METHODS: Sixty patients scheduled for total knee replacement were randomly assigned to receive continuous femoral nerve block with or without perineural space expansion using 10 mL dextrose 5% in water (D5W) flush before stimulation-guided catheter placement. Femoral block was initiated with a 5-mL bolus followed by an infusion of 5 mL/h ropivacaine 0.2% during the 2-hour surgery. The number of attempts before successful placement of the stimulating catheter and the resistance during its insertion were assessed. Patients also received obturator nerve blocks by using ropivacaine 0.75% (10 mL) and sciatic nerve blocks (20 mL). The number of boluses of ropivacaine 0.2% needed to achieve zero VAS scoring was recorded in the postanesthesia care unit during the 2-hour stay. Images of the contrast spread were also studied. RESULTS: There were 30 patients in each group. The number of successful catheter placements at the first attempt was higher with expansion than without (22 vs. 8, P = .007). The resistance felt during insertion was lower with than without expansion (P = .01). More boluses of ropivacaine were required postoperatively without expansion (P = .03). No difference between groups was found regarding the images of the contrast spread. CONCLUSION: Expansion of the perineural space with D5W is useful for catheter placement in continuous femoral nerve block.

Single-breath vital capacity rapid inhalation induction with sevoflurane: feasibility in children.

BACKGROUND: Single-breath vital capacity technique is currently administered for inhalation induction of anesthesia with sevoflurane in adults. Because sevoflurane is used in children, the aim of this open nonrandomized trial was to explore the feasibility and acceptance of this technique in midazolam premedicated patients aged from 4 to 15 years old. METHODS: A pediatric population (n = 118) was instructed in the vital capacity technique after their arrival in the induction room in a standardized and playful manner. Induction was performed with a circle-absorber breathing circuit, primed with sevoflurane 7% in 100% O2. Success of the single-breath vital capacity, delay of induction, hemodynamic and airway tolerance, acceptance by the children and side effects were analyzed. A multivariate logistic regression model was used to identify independent risk factors associated with the failure of the vital capacity technique. RESULTS: Single-breath vital capacity technique was achieved by 57% of the children. The success rate highly correlated with age and ranged from 10% in 4-5 years old to 75% at 11 years and 95% by 14 years. Other factors for success were cooperation and understanding. The need for more than two explanations of the technique was predictive of failure. Delays in the loss of the eyelash reflex and central pupil myosis were obtained in 34 s (18-50) and 242 s (145-278), respectively [median (interquartile ranges)]. Hemodynamic tolerance was good with few airway complications. CONCLUSION: Rapid anesthesia induction using a single-breath technique with 7% sevoflurane is effective and well tolerated in children, particularly in those above 9 years of age, and in fact, success rate was markedly lower in the young age groups.

The value of adding sciatic block to continuous femoral block for analgesia after total knee replacement.

BACKGROUND AND OBJECTIVES: The benefit of adding a sciatic nerve block to the femoral block to improve analgesia after total knee replacement is controversial. The aim of this study is to address this controversy in a prospective, comparative, and randomized study. METHODS: Patients were allocated randomly to receive a continuous femoral nerve block or continuous blocks of both the femoral and sciatic nerves. Stimulating catheters were used in all cases. A loading dose of 15 mL ropivacaine 0.75% was injected into each catheter, followed by administration of ropivacaine 0.2% (2-5 mL/h infusion via the femoral catheter; bolus 10 mL repeated every 12 hours in the sciatic catheter). The primary outcome was visual analog scale (VAS) scores (0 = no pain, 100 mm = worst pain) in postanesthesia care unit and in the 48-hour period after surgery. The secondary outcomes were amplitude of knee flexion, morphine consumption, and occurrence of postoperative nausea and vomiting (PONV). RESULTS: The VAS scores at rest were significantly higher when there was only continuous femoral nerve block than when there was both continuous femoral and sciatic nerve blocks. This difference progressively decreased and disappeared at 36 hours after surgery. The combined femoral and sciatic blocks decreased the morphine consumption by 81% and significantly decreased the occurrence of PONV. CONCLUSION: During the 36 hours immediately after total knee replacement, the combination of continuous femoral and sciatic nerve blocks improves analgesia while decreasing morphine consumption and PONV.

Prolongation of epidural bupivacaine effects with hyaluronic acid in rabbits.

To assess the prolongation of epidural bupivacaine by hyaluronic acid viscous formulations we designed a cross-over study in rabbits. Different doses of bupivacaine (3 or 6 mg) either as a solution (bupivacaine hydrochloride), or as viscous formulations with hyaluronic acid (bupivacaine base and bupivacaine hydrochloride) were administered in a rabbit model of epidural anesthesia. In the first part of the study, in vitro release characteristics were determined. Then pharmacodynamic effects and pharmacokinetic profiles of each bupivacaine formulation were studied. The rank order release rate of bupivacaine in vitro was always hydrochloride solution >> viscous physical mixture of bupivacaine with hyaluronic acid > viscous ionic complex of bupivacaine base with hyaluronic acid. Onset time of epidural anesthesia was similar whatever the formulation of bupivacaine used. We did not find any blockade prolongation when 3mg bupivacaine was administered, but significant blockade prolongations were observed with viscous formulations incorporating 6 mg bupivacaine. The observed reduction in the absorption rate of bupivacaine into the systemic circulation for both viscous hyaluronic formulations after 6 mg of bupivacaine may explain the prolongation of spinal effects. Drug release and duration of action were found to be viscosity controlled as linear relationships were found between pharmacodynamic effects and viscosity. Our results were in accordance with those reported with bupivacaine-cyclodextrin complex, another formulation with a molecular dispersion of the drug, resulting in a moderate prolongation of action.

Computed tomography scanning of the sciatic nerve posterior to the femur: Practical implications for the lateral midfemoral block.

BACKGROUND AND OBJECTIVES: Using computed tomography (CT) scans of the thighs, this study addresses sciatic nerve anatomy at the injection site for the lateral midfemoral sciatic nerve block. It addresses the recommendation of neutral leg rotation to facilitate block placement. METHOD: This prospective and descriptive study involves 21 patients scheduled for CT scan imaging of the lower limbs. Transverse CT scans were analyzed at 20, 25, and 30 cm distal to the upper border of the greater trochanter (GT) of the femur with the knee externally rotated by 30 degrees. The angle alpha formed by the broad axis of the sciatic nerve and the coronal plane, skin-to-nerve distance, great vessel-to-nerve distance, division of the sciatic nerve, and widths of the perineural space were assessed. Values are expressed as mean +/- SD. RESULTS: At 20, 25, and 30 cm distal to the GT, the alpha angle was 50 degrees +/- 14 degrees, 55 degrees +/- 13 degrees, and 56 degrees +/- 26 degrees, respectively. This angle increased to nearly 90 degrees when the knee was rotated to a neutral position. The skin-to-nerve distance was 5.9 +/- 1.1 cm, 5.4 +/- 0.9 cm, and 5.7 +/- 1.1 cm. The section width of the perineural space was 1.8 +/- 0.9 cm(2), 3.9 +/- 2 cm(2), and 5.6 +/- 2.4 cm(2). The sciatic nerve was divided in 27% of subjects at 20 cm and in 90% at 30 cm distal. CONCLUSION: The characteristics of sciatic nerve anatomy described in this study support observations and clinical recommendations regarding lateral midfemoral sciatic nerve block.

Continuous peripheral nerve blocks with stimulating catheters.

BACKGROUND AND OBJECTIVES: This study evaluated the efficacy of stimulating catheters used for continuous peripheral nerve blocks as a means of immediate verification and confirmation of correct catheter position. METHODS: This observational study presents our experience with 130 stimulating catheters used in 40 intersternocleidomastoid, 24 axillary, 47 femoral, and 19 lateral midfemoral sciatic nerve blocks. Placement characteristics (amperage, depth of introducer needle or catheter insertion, elicited motor responses), subsequent postoperative analgesia, and catheter position evaluated with the radiopaque dye analysis were all studied. RESULTS: Except in femoral blocks, characteristics of motor responses elicited (1 Hz, 0,1 ms) by the introducer assembly and catheter differed. The amperage required to elicit motor responses typically was higher with the catheter than with the introducer needle (1.6 [0.2 to 4 mA] v 0.5 [0.4 to 1 mA] P <.0001). The ability to elicit a motor response with the stimulating catheter correlated with successful clinical anesthesia in 124 cases. Opacified radiography showed no aberrant position in these cases. Three catheters for upper limb block failed to stimulate, provided poor anesthesia, and had radiologic evidence of aberrant position. Even though they failed to stimulate, 3 catheters for sciatic block functioned well, and the opacified radiography showed correct position. CONCLUSION: The ability to electrostimulate nerves using an in situ catheter increases success rate in catheter placement for continuous peripheral nerve blocks. Further controlled investigations are necessary to compare this technique with more conventional methods in terms of cost and utility for various peripheral nerve blocks.

Nalbuphine reverses urinary effects of epidural morphine: a case report.

We report the successful use of nalbuphine, a mu-receptor antagonist-kappa-receptor agonist, to reverse the adverse effects on the bladder of epidural morphine.

Intrathecal ropivacaine in rabbits: pharmacodynamic and neurotoxicologic study.

BACKGROUND: Ropivacaine is available for spinal or intrathecal use in humans, although data on neurotoxicity after spinal injection are not yet available. The authors experimentally determined the relationship between doses of intrathecal ropivacaine and spinal effects and local neurotoxic effects. METHODS: Eighty rabbits equipped with an intrathecal lumbar catheter were studied. Sixty were randomly assigned to receive 0.2 ml of intrathecal solutions as a sole injection of: 0.2%, 0.75%, 1.0%, and 2.0% ropivacaine (doses from 0.4-4.0 mg; groups R0.2 to R2.0), 5.0% lidocaine (10 mg; group L), or 0.9% NaCl as control (group C). Twenty other rabbits received either repeated injections of 0.2 ml of 0.2% ropivacaine every 2 days during 2 weeks (total dose of 2.8 mg; group RINT); or a continuous intrathecal infusion of 0.2% ropivacaine at the rate of 1.8 ml/h over 45 min (2.7 mg; group RCONT). Injection rate was 30 s in all groups except Rcont. Time to onset, duration and extent of motor block, and variations of mean arterial blood pressure were recorded in all groups. Somatosensory evoked potentials were also recorded in group RCONT and RINT. Seven days after the last intrathecal injection spinal cord and nerves were sampled for histopathologic study. RESULTS: In groups R0.2 and RINT, the lowest dose of ropivacaine induced a clinically visible spinal block in only 50% of rabbits, but SEPs recorded in group RINT were decreased by 70% in the lumbar dermatome. Complete motor block was observed with doses greater than 1.5 mg of ropivacaine (group RCONT and R0.75 to R2.0). Onset time was shorter and duration of block increased as doses of ropivacaine increased. Significant hypotension was observed only with 4.0 mg of ropivacaine (concentration of 2.0%). Complete paralysis and hypotension were observed with 5.0% lidocaine. No neurologic clinical lesion was observed in rabbits receiving saline or ropivacaine within the 7 days after the last intrathecal injection, and histopathologic study revealed no sign of neurotoxicity in these groups. In contrast, intrathecal lidocaine induced clinical and histopathologic changes. CONCLUSION: Ropivacaine induced dose-dependent spinal anesthesia, and did not induce any neurotoxicologic lesion in this experimental animal model.

Is haemostasis biological screening always useful before performing a neuraxial blockade in children?

BACKGROUND: Because of the lack of controlled studies, there is no consensus of opinion about the practice of routine haemostasis tests before neuraxial blockade in children. The purpose of this study was to compare the influence of two different strategies of coagulation evaluation on the incidence of diagnosed coagulopathies leading to a modification of the preoperative or anaesthetic management in children who were scheduled for caudal, epidural or intrathecal block. METHODS: For a 24-month period (period 1, retrospective study, n=751), haemostasis screening was undertaken only after family and personal history and physical examination in all patients. For the following 24 months (period 2, prospective study, n=958), a standardized questionnaire was used. In addition, routine tests (prothrombin, partial thromboplastin time, platelet count) were performed in children who where not yet walking. In older children, coagulation tests were undertaken as in period 1. RESULTS: Overall, 26 significant abnormalities were diagnosed. Coagulation tests were performed in 16.2% (period 1) and 78.2% (period 2) of the children, who were not yet walking. Routine tests did not improve the diagnosis of haemostasis abnormalities justifying a modification of the preoperative and anaesthetic management (2.2% from 406 children in period 1 vs 4.1% from 266 children in period 2). The predictive positive value of routine tests (period 2) was 19%, vs 45% for specific tests (period 1) (P < 0.001). In older children, the use of a standardized form increased the number of haemostasis screenings without improvement of diagnosis leading to modified preoperative management (0.3% from 315 children in period 1 vs 0.5% from 628 children in period 2). CONCLUSIONS: When routine testing is performed in nonwalking children, the screening number increases without leading to a higher number of anaesthetic management changes, suggesting that routine testing does not seem to provide much extra information in the absence of a positive history.