Anne Weber

Epinephrine Does Not Prolong the Analgesia of 20 ml Ropivacaine 0.5% or 0.2% in a Femoral Three-in-one Block

We tested the effect of epinephrine added to 20 mL ropivacaine 0.5% and 0.2% on postoperative analgesia via a femoral catheter after total knee replacement. Forty-one patients undergoing total knee replacement under combined peripheral block/general anesthesia were randomly allocated to two groups. After insertion of a femoral catheter, 21 patients in the Ropivacaine-Epinephrine (ROPI-EPI) group received 20 mL ropivacaine 0.5% plus epinephrine 1:200,000, whereas 20 patients in the Ropivacaine group (ROPI) received 20 mL plain ropivacaine 0.5%. Thereafter, a sciatic block with 30 mL bupivacaine 0.5% plus epinephrine 1:200,000 was performed in all patients, followed by general anesthesia. After surgery, patient-controlled analgesia (PCA) with ropivacaine 0.2% plus epinephrine 1:200,000 for Group ROPI-EPI and plain ropivacaine 0.2% for Group ROPI was available via the femoral catheter (200 mL ropivacaine 0.2% ± epinephrine, bolus 20 mL, lockout 120 min). The patients were instructed to use PCA when the knee pain score was >3 cm. The interval between the initial ropivacaine injection and the first PCA injection determined the duration of 20 mL ropivacaine 0.5% ± epinephrine, whereas the interval between the first and second PCA injection determined the duration of 20 mL ropivacaine 0.2% ± epinephrine. The average duration of ropivacaine 0.5% was 657 ± 345 min for the ROPI-EPI group and 718 ± 423 min for the ROPI group (NS), whereas for ropivacaine 0.2%, the average duration was 409 ± 245 min for the ROPI-EPI group and 419 ± 339 min for the ROPI group (not significant). We conclude that epinephrine does not influence the duration of analgesia of the ropivacaine concentrations investigated.

Cerebrospinal Fluid Density Influences Extent of Plain Bupivacaine Spinal Anesthesia

Background The attempts to explain the unpredictability of extent of spinal block provided by plain local anesthetic solutions have resulted in many clinical reports; however, causes of this uncertainty are as yet unknown. Recently, normal values of the human cerebrospinal fluid densities have been studied showing important interindividual variations, especially between females and males. The current study was designed to evaluate as primary endpoint the influence of cerebrospinal fluid density values on the extent of spinal block with plain bupivacaine. The ancillary endpoints were search of factors explaining the interindividual differences in cerebrospinal fluid density values reported and determination of the relation between upper extent and regression of spinal anesthesia. Methods Sixty-four consecutive patients undergoing peripheral orthopedic surgery with spinal block were enrolled. Spinal anesthesia was performed in the lateral decubitus position with the operated side upward. Two milliliters of cerebrospinal fluid was sampled before injection of 3 ml plain bupivacaine 0.5%. The patient was immediately turned supine and remained in the horizontal position until the end of the study. Maximal sensory block level and time to sensory regression to L4 were determined for each patient enrolled. Cerebrospinal fluid and bupivacaine densities as well as cerebrospinal proteins, glucose, sodium, and chloride concentrations were measured. Results A highly significant correlation between cerebrospinal fluid density and maximal sensory block level was found (P = 0.0004). However, this correlation was poorly predictive (R2 = 0.37). Cerebrospinal fluid density, proteins, and glucose concentrations were significantly higher in men than in women: 1.000567 ± 0.000091 versus 1.000501 ± 0.000109 g/ml (P = 0.014), 0.46 ± 0.18 versus 0.32 ± 0.13 g/l (P = 0.001), and 3.27 ± 0.7 versus 2.93 ± 0.5 mm (P = 0.023), respectively. A highly significant (P = 0.0004) and predictive (R2 = 0.73) inverse correlation was found between maximal upper sensory extent and sensory regression to L4. Conclusion These findings indicate an influence of cerebrospinal fluid density on subarachnoid distribution of 3 ml plain bupivacaine 0.5% and show that with higher cerebrospinal fluid densities, a higher spinal block level can be expected.

A comparison of intrathecal analgesia with fentanyl or sufentanil after total hip replacement.

We designed this study to compare the postoperative analgesic effects of intrathecal fentanyl and sufentanil, the end points being onset, quality, and duration of action. A total of 42 geriatric patients, scheduled for elective total hip replacement under continuous spinal anesthesia, were randomized in two double-blinded groups as soon as they experienced a pain score higher than 3 of 10 on the visual analog scale in the recovery room. Either 7.5 &mgr;g sufentanil or 40 &mgr;g fentanyl in 2 mL normal saline were intrathecally administered. Pain scores, rescue analgesia (ketorolac and morphine), and adverse effects (respiratory depression, postoperative nausea and vomiting, and itching) were recorded for 24 h after surgery. In both groups, comparing sufentanil to fentanyl, the time to a pain score <3 (9 ± 9 vs 11 ± 8 min), the time to the lowest pain score (18 ± 6 vs 20 ± 15 min), and the time to the first systemic analgesic intervention for a pain score >3 (241 ± 102 vs 214 ± 120 min) were comparable as were the analgesic requirements during the first 24 h. We conclude that, after total hip replacement, both lipid soluble opioids produce excellent analgesia with comparable onset, duration of action, and low incidence of minor adverse effects. Implications: We compared the postoperative analgesic properties of 40 &mgr;g intrathecal fentanyl and 7.5 &mgr;g sufentanil after total hip replacement. Both opioids provided satisfactory analgesia, with comparable onset (11 ± 8 vs 9 ± 9 min) and duration of action (214 ± 120 vs 241 ± 102 min), as well as low incidence of minor side effects.

Portopulmonary hypertension and hepatopulmonary syndrome

Portopulmonary hypertension (POPH) and hepatopulmonary syndrome (HPS) are two frequent complications of liver disease, with prevalence among liver transplant candidates of 6% and 10%, respectively. Both conditions result from a lack of hepatic clearance of vasoactive substances produced in the splanchnic territory. Subsequently, these substances cause mainly pulmonary vascular remodeling and some degree of vasoconstriction in POPH with resulting elevated pulmonary pressure and right ventricular dysfunction. In HPS the vasoactive mediators cause intrapulmonary shunts with hypoxemia. Medical treatment is disappointing overall. Whereas liver transplantation (LT) results in the disappearance of HPS within six to twelve months, its effect on POPH is highly unpredictable. Modern strategies in managing HPS and POPH rely on a thorough screening and grading of the diseases severity, in order to tailor the appropriate therapy and select only the patients who will benefit from LT. The anesthesiologist plays a central role in managing these high-risk patients. Indeed, the important hemodynamic and respiratory modifications of the perioperative period must be avoided through continuation of the preoperatively initiated drugs, appropriate intraoperative monitoring and proper hemodynamic and respiratory therapies.

Intrathecal sufentanil is more potent than intravenous for postoperative analgesia after total-hip replacement.

Background and Objectives In our clinical experience, sufentanil is more effective when administered intrathecally than intravenously. To test this hypothesis, we compared the analgesic characteristics of 7.5 μg of intrathecal or intravenous sufentanil for pain relief after total-hip replacement. Methods A randomized, double-blind study was conducted of 40 patients older than 75 years who experienced total-hip arthroplasty in which continuous spinal anesthesia was administered. In the recovery room, as soon as a pain score higher than 3 on a scale of 10 on a visual analog scale was reported, either 7.5 μg intrathecal or 7.5 μg intravenous sufentanil were given. If the pain score remained higher than 3 at 20 minutes after sufentanil administration,1.25 mg of “rescue” intrathecal bupivacaine were given. Results During the first 20 minutes after intrathecal or intravenous injection, a significantly faster relief of pain was observed for the intrathecal group from 2.5 until 20 minutes. Significantly, more patients needed rescue bupivacaine in the intravenous group (7 of 20 v 0 of 20, P < .008), whereas significantly more patients in the intrathecal group reached a pain score of 0 (20 of 20 v 9 of 20, P < .001). The time to the first analgesic intervention for a pain score greater than 3 was significantly longer in the intrathecal group (224 ± 100 v 98 ± 60 minutes, P < .001). Pruritus was observed only in 5 patients of the intrathecal group (P < .047), whereas peripheral oxygen saturation under 95% was observed only in 6 patients in the intravenous group (P < .045). Conclusions After total-hip replacement, intrathecal route of sufentanil administration rapidly offers excellent analgesia of better quality and longer duration when compared with the intravenous route.

Duration of analgesia is similar when 15, 20, 25 and 30 mL of ropivacaine 0.5% are administered via a femoral catheter

PurposeThis dose-response study was designed to determine the most appropriate dose of ropivacaine 0.5% injected via an indwelling femoral catheter for perioperative peripheral analgesia for total knee replacement (TKR).Methods84 patients were allocated randomly to four groups and received, via a femoral catheter, either 15, 20, 25 or 30 mL of ropivacaine 0.5% in a double-blind fashion. An anterior sciatic block with 20 mL bupivacaine 0.5% was also performed. The evolution of sensory block of femoral, obturator and lateral femoral cutaneous nerves and motor block of femoral nerve were tested every five minutes during the first 30 min. The percentage of patients with complete sensory block of both femoral and obturator nerves determined success rate. General anesthesia was then induced. After surgery, patient-controlled analgesia (PCA) with ropivacaine 0.2% was available via the femoral catheter. The interval between the initial injection and the first PCA administration determined duration of action.ResultsThe duration of action was not different between the four solutions tested i.e., 534 ± 379 min for 15 mL, 799 ± 364 min for 20 mL, 624 ± 342 min for 25 mL and 644 ± 266 min for 30 mL. The percentage of patients with complete sensory femoral and obturator blocks was, respectively, 60%, 95%, 85% and 70% for 15, 20, 25 and 30 mL (P = 0.008/15 mL vs 20 mL).ConclusionAlthough there is no difference in duration of analgesia, because of better sensory spread, 20 mL of ropivacaine 0.5% appears to be the most appropriate dose for peripheral analgesia after TKR.ObjectifL’étude dose-réponse visait à déterminer la meilleure dose de ropivacaïne à 0,5 % injectée par cathéter fémoral à demeure pour l’analgésie périopératoire périphérique lors d’une arthroplastie totale du genou (ATG).MéthodeNous avons réparti au hasard, en quatre groupes, 84 patients qui ont reçu par cathéter fémoral 15, 20, 25 ou 30 mL de ropivacaïne à 0,5 % en double insu. Un bloc sciatique antérieur a aussi été réalisé avec 20 mL de bupivacaïne à 0,5 %. L’évolution du bloc sensitif des nerfs fémoral, obturateur et cutané latéral de la cuisse et du bloc moteur du nerf fémoral a été vérifiée toutes les cinq minutes pendant les 30 premières minutes. Le pourcentage de patients qui présentait un bloc sensitif complet des nerfs fémoral et obturateur a déterminé le taux de succès. L’anesthésie générale a ensuite été induite. Après l’opération, l’analgésie auto-contrôlée (AAC) avec de la ropivacaïne à 0,2 % était disponible par cathéter fémoral. L’intervalle entre l’injection initiale et la première administration d’AAC a donné la durée d’action.RésultatsLa durée d’action a été comparable dans tous les groupes : 534 ± 379 min avec 15 mL, 799 ± 364 min avec 20 mL, 624 ± 342 min avec 25 mL et 644 ± 266 min avec 30 mL. Le pourcentage de patients présentant un bloc sensitif complet des nerfs fémoral et obturateur a été respectivement de 60 %, 95 %, 85 % et 70 % pour les doses de 15, 20, 25 et 30 mL (P = 0,008/15 mL vs20 mL).ConclusionMême si la durée de l’analgésie est équivalente, grâce à une meilleure diffusion sensitive, 20 mL de ropivacaïne à 0,5 % semble être la dose la plus appropriée pour l’analgésie périphérique après une ATG.

No Differences Between 20, 30, or 40 mL Ropivacaine 0.5% in Continuous Lateral Popliteal Sciatic-Nerve Block

Background and Objectives: The aim of this study was to compare the anesthetic and analgesic characteristics of the administration of an initial bolus of 20, 30, or 40 mL of ropivacaine 0.5% through a lateral popliteal sciatic catheter. Methods: Sixty patients scheduled for foot surgery under continuous sciatic lateral popliteal nerve block were included in this double-blinded study. Patients were randomly assigned to 1 of 3 groups: 20 mL, 30 mL, or 40 mL of ropivacaine 0.5%. Time to obtain a complete sensory block and duration of analgesia were recorded. Failure of the continuous block and complications such as technical or neurologic problems were noted. Results: Data are presented as mean ± SD, median and ranges, or percent of patients and were compared by application of analysis of variance or Kruskal-Wallis when required. Time to complete sensory block (31 [10-70] v 25 [5-50] v 25 [5-40] min), percentage of failure (5% v 5% v 0%), and duration of action (995 [278-1,800] v 967 [420-2,175] v 915 [190-1,900] min) were not statistically different between 20 mL, 30 mL, and 40 mL ropivacaine 0.5% groups, respectively. No complications were noted. Conclusions: This dose-response study shows that 20 mL of ropivacaine 0.5% injected through an indwelling lateral popliteal catheter is the optimal dose for foot surgery. Higher doses of 30 mL or 40 mL did not provide any further advantage.