Concentrations Of Ropivacaine Research Articles

Plasma ropivacaine concentrations after ultrasound-guided transversus abdominis plane block for open retropubic prostatectomy

Ropivacaine-induced vasoconstriction may affect the early absorption speed of ropivacaine; however, the effects of dose on pharmacokinetics following transversus abdominis plane (TAP) block have not been studied. In this study, we have examined plasma ropivacaine concentrations following TAP block with various ropivacaine concentrations (0.25, 0.5, and 0.75 %). With the approval of our University ethics committee and informed consent, 39 adult patients undergoing open retropubic prostatectomy were enrolled. Patients were randomly assigned to three groups (n = 13 each) receiving TAP block with 20 ml (10 ml each side) of different concentrations of ropivacaine. To determine plasma concentrations, blood samples were drawn before and 15, 30, 45, 60, 90, 120, and 180 min after completion of bilateral TAP blocks. Plasma ropivacaine concentrations were analyzed by gas chromatography with mass spectrometry. We found that the peak plasma concentrations (C(max)) increased dose dependently (0.41 ± 0.14, 0.89 ± 0.55, and 1.56 ± 0.50 µg/ml), but the times to C(max) (23.0 ± 15.8, 23.1 ± 14.5, and 20.8 ± 11.5 min) were not different between 0.25, 0.5, and 0.75 % ropivacaine doses, respectively. Terminal elimination half-life (t(1/2)), total body clearance (CL), and distribution volume (V(d)) were also not different among the three groups. Ropivacaine concentration did not alter pharmacokinetic profile following TAP blocks.

Effects of intraneural and perineural injection and concentration of Ropivacaine on nerve injury during peripheral nerve block in Wistar rats

Introduction: Injury during peripheral nerve blocks is relatively uncommon, but potentially devastating complication. Recent studies emphasized that location of needle insertion in relationship to the fascicles may be the predominant factor that determines the risk for neurologic complications. However, it is wellestablished that concentration of local anesthetic is also associated with the risk for injury. In this study, we examined the effect of location of injection and concentration of Ropivacaine on risk for neurologic complications. Our hypothesis is that location of the injection is more prognostic for occurrence of nerve injury than the concentration of Ropivacaine.Methods: In experimental design of the study fi fty Wistar rats were used and sciatic nerves were randomized to receive: Ropivacaine or 0.9% NaCl, either intraneurally or perineurally. Pressure data during application was acquired by using a manometer and was analyzed using software package BioBench. Neurologic examination was performed thought the following seven days, there after the rats were sacrificed while sciatic nerves were extracted for histological examination.Results: Independently of tested solution intraneural injections in most of cases resulted with high injection pressure, followed by obvious neurologic defi cit and microscopic destruction of peripheral nerves. Also, low injection pressure, applied either in perineural or intraneural extrafascicular area, resulted with transitory neurologic defi cit and without destruction of the nerve normal histological structure.Conclusions: The main mechanism which leads to neurologic injury combined with peripheral nerve blockade is intrafascicular injection. Higher concentrations of Ropivacaine during intrafascicular applications magnify nerve injury.

Comparison of local infiltration anesthesia with different concentrations of ropivacaine for postoperative analgesia in pediatric patients undergoing tonsillectomy

Objective To compare local infiltration anesthesia with different concentrations of ropivacaine for postoperative analgesia in pediatric patients undergoing tonsillectomy.Methods Sixty ASA physical status Ⅰ patients of both sexes,aged 6-12 yr,weighing 18-41 kg,scheduled for elective tonsillectomy,were randomly divided into 3 groups (n =20 each) using a random number table:control group (group C); 0.2％ ropivacaine group (group R1) ; 0.5 ％ ropivacaine group (group R2).Anesthesia was induced with inhalation of sevoflurane,injection of sufentanil and cisatracurium and maintained with inhalation of sevoflurane and iv infusion of remifentanil.The tonsil was locally infiltrated vith 0.2 ％ and 0.5％ ropivacaine (3-5 ml on each side of the tonsil) before surgery in R1 and R2 groups,respectively.Tonsillectomy was performed under general anesthesia.At 1,3,6,12,and 24 h after surgery,pain was assessed using faces pain scale-revised (FPS-R).Paracetamol 5 mg/kg was used as rescue analgesic when FPS-R scores ≥4.The interval between awake extubation and the first request for analgesic,requirement for postoperative analgesic and development of adverse effects were recorded.Results Compared with group C,the interval between awake extubation and the first request for analgesic was significantly prolonged,and the requirement for postoperative analgesic was decreased in R1 and R2 groups (P ＜ 0.05).Compared with group R1,the interval between awake extubation and the first request for analgesic was significantly prolonged,and the requirement for postoperative analgesic was decreased in R2 group (P ＜ 0.05).There was no significant difference in the incidence of adverse effects between the two groups (P ＞ 0.05).Conclusion The optinum concentration of locally infiltrated ropivacaine is 0.5 ％ for postoperative analgesia in pediatric patients undergoing tonsillectomy. Key words: Amides ; Anesthesia, local ; Tonsillectomy ; Pain, postoperative ; Child

Plasma ropivacaine concentrations during bilateral transversus abdominis plane infusions

BackgroundThe transversus abdominis plane (TAP) block is a regional anaesthetic technique that blocks abdominal wall somatic afferent nerves. We conducted a prospective observational study to evaluate the venous plasma concentrations of ropivacaine during a continuous TAP infusion. MethodsTwenty patients who were planned to undergo intra-abdominal cavity surgery requiring a mid-line laparotomy incision were enrolled. Patients were excluded if they had a history of chronic pain, opioid tolerance, renal or hepatic impairment, or contraindication to study medications. Subjects received a standardized general anaesthetic, and at the completion of surgery, ultrasound-guided subcostal or posterior TAP blocks and catheters. A TAP infusion of 2 mg ml−1 ropivacaine was administered for 72 h after operation. Data collection during the 72 h included morphine requirements, pain scores, and plasma ropivacaine levels. ResultsTAP blocks and catheters were successfully inserted in all recruited subjects. The fourth subject experienced neurological symptoms attributed to local anaesthetic toxicity, but did not have high plasma ropivacaine concentrations. However, the protocol was amended for the subsequent 16 subjects, to a weight-based dosing regimen. The range of total plasma ropivacaine concentrations was 0.98–3.41 mg litre−1 for posterior infusions and 0.96–3.48 mg litre−1 for subcostal infusions. Four subjects had total ropivacaine levels >3.4 mg litre−1. The range of unbound plasma ropivacaine concentrations was 0.022–0.135 mg litre−1 for posterior infusions and 0.031–0.120 mg litre−1 for subcostal infusions. ConclusionGiven the potential for high plasma concentrations from a bilateral TAP infusion technique, attention should be paid to individualized dosing strategies.

Cytotoxicity of Local Anesthetics on Human Mesenchymal Stem Cells in Vitro

The purpose of this study was to investigate the cytotoxic potency of local anesthetics on human mesenchymal stem cells (MSCs) before and after chondrogenic differentiation. MSCs were exposed to equal and equipotent concentrations of bupivacaine, ropivacaine, and mepivacaine for 1 hour. Cell viability, apoptosis, and necrosis were determined using flow cytometry and live/dead staining. After chondrogenic differentiation, MSC viability was determined in aggregates exposed to equipotent concentrations of the named agents, applying fluorescence microscopy. All local anesthetics showed detrimental cytotoxic effects on MSC monolayer cultures in a concentration- and time-specific manner. Minimum viability rates were found 96 hours after a 1-hour exposure. Bupivacaine 0.5% caused a reduction of vital MSCs to 5% ± 1%. Sixteen percent ± 2% viable cells were detected after treatment with 0.75% ropivacaine. Exposure to 2% mepivacaine decreased vitality rates to 1% ± 0%. Ropivacaine was significantly less cytotoxic than were bupivacaine and mepivacaine. Immediate cell death was mainly caused by necrosis followed by apoptosis afterward. Viability rates of MSCs embedded in cartilaginous tissue after chondrogenic differentiation were not reduced by local anesthetic treatment. Local anesthetics are cytotoxic to MSCs in a concentration-, time-, and agent-dependent manner in monolayer cultures but not in whole-tissue probes. MSCs are applied for treatment of cartilage defects. Intra-articular application of local anesthesia is a common procedure in pain management and has shown chondrotoxic effects. Therefore, it is crucial to evaluate the impact of local anesthetics on human MSCs and regenerative cartilage tissue engineering.

Transversus abdominis plane block provides postoperative analgesic effects after cesarean section: Additional analgesia to epidural morphine alone

The aim of our study was: (i) to investigate whether transversus abdominis plane (TAP) block confers additional analgesic effects to epidural morphine alone; and (ii) to determine plasma levels of local anesthetics after TAP block in post-cesarean women. The subjects were parturients undergoing cesarean section under combined spinal-epidural anesthesia. Morphine (2 mg) was administered to the epidural space close to the end of surgery. Women who desired TAP block were allocated to the TAP group. Women who did not undergo TAP block were allocated to the control group. In the TAP group, 20 mL of either 0.375% ropivacaine or 0.3% levobupivacaine was infused to both sides of the transversus abdominis plane after surgery. All patients were placed on a patient-controlled i.v. analgesia regimen with morphine after surgery. Time to the first morphine request and amount of morphine consumption within 24 h after surgery were compared in patients with and without TAP block. Plasma concentrations of local anesthetics were determined at 15, 30 and 60 min after TAP block. Forty and 54 patients were allocated to the control and TAP group, respectively. The median time to the first morphine request was longer (555 vs 215 min), and the median cumulative morphine consumption within 24 h was lower (5.3 vs 7.7 mg) in the TAP group than in the control group. The maximum median concentrations of ropivacaine and bupivacaine after TAP block were 784 and 553 ng/mL, respectively. TAP block had additional analgesic effects to epidural morphine alone.

The Cytotoxicity of Bupivacaine, Ropivacaine, and Mepivacaine on Human Chondrocytes and Cartilage

Intraarticular injections of local anesthetics are frequently used as part of multimodal pain regimens. However, recent data suggest that local anesthetics affect chondrocyte viability. In this study, we assessed the chondrotoxic effects of mepivacaine, ropivacaine, and bupivacaine. We hypothesized that specific cytotoxic potencies directly correlate with analgesic potencies, and that cytotoxic effects in intact cartilage are different than in osteoarthritic tissue. Human articular chondrocytes were exposed to equal and equipotent concentrations of bupivacaine, ropivacaine, and mepivacaine for 1 hour. Cell viability, apoptosis, and necrosis were determined at predefined time points using flow cytometry, live-dead staining, and caspase detection. Intact and osteoarthritic human cartilage explants were treated with equipotent concentrations of named drugs to determine cell viability applying fluorescence microscopy. Chondrotoxic effects increased from ropivacaine to mepivacaine to bupivacaine in a time-dependent and concentration-dependent manner. Compared with control, bupivacaine 0.5% decreased chondrocyte viability to 78% ± 9% (P = 0.0183) 1 hour and 16% ± 10% (P < 0.0001) 24 hours later, as determined by live-dead staining in monolayer cultures. Viability rates were reduced to 80% ± 7% (P = 0.0475) 1 hour and 80% ± 10% (P = 0.0095) 24 hours after treatment with ropivacaine 0.75%. After exposure to mepivacaine 2%, viable cells were scored 36% ± 6% (P < 0.0001) after 1 hour and 30% ± 11% (P < 0.0001) after 24 hours. Ropivacaine treatment was less chondrotoxic than bupivacaine (P = 0.0006) and mepivacaine exposure (P = 0.0059). Exposure to concentrations up to 0.25% of bupivacaine, 0.5% of ropivacaine, and 0.5% of mepivacaine did not reveal significant chondrotoxicity in flow cytometry. However, chondrotoxicity did not correlate with potency of local anesthetics. Immediate cell death was mainly due to necrosis followed by apoptosis. Cellular death rates were clearly higher in osteoarthritic compared with intact cartilage after bupivacaine, mepivacaine, and ropivacaine treatment in a decreasing order. Bupivacaine, ropivacaine, and mepivacaine are chondrotoxic in a time-dependent, concentration-dependent, and drug-dependent manner. Chondrotoxic and analgesic potencies do not directly correlate. Cellular death rates were higher in osteoarthritic compared with intact cartilage after local anesthetic treatment.

Symptomatic local anaesthetic toxicity and plasma ropivacaine concentrations after transversus abdominis plane block for Caesarean section

The transversus abdominis plane (TAP) block involves injecting a large volume of local anaesthetic between the muscles of the abdominal wall. Plasma concentrations of ropivacaine after gynaecological laparotomy are potentially high enough to result in systemic toxicity, and there are pharmacokinetic reasons why pregnancy may increase susceptibility to local anaesthetic toxicity. Adult female patients (n=30) undergoing elective Caesarean section under spinal anaesthesia received bilateral ultrasound-guided TAP blocks after wound closure (2.5 mg kg(-1) of ropivacaine diluted to 40 ml). Venous blood samples were collected at 10, 20, 30, 45, 60, 90, 120, 180 and 240 min following the block. Blood samples were assayed for total and free ropivacaine concentrations. Patients were assessed for symptoms of local anaesthetic toxicity. The mean [standard deviation (SD)] peak total concentration of ropivacaine occurred at 30 min post-injection and was 1.82 (0.69) μg ml(-1). The maximum detected concentration in any patient was 3.76 μg ml(-1) (at 10 min post-injection). Three patients reported symptoms of mild neurotoxicity, and the mean (SD) peak levels were elevated in these patients, 2.70 (0.46) µg ml(-1). TAP blocks can result in elevated plasma ropivacaine concentrations in patients undergoing Caesarean section, which may be associated with neurotoxicity.

Pharmacokinetics and efficacy of ropivacaine in Chinese patients following intra-articular administration

The purpose of the present study was to investigate the pharmacokinetics and efficacy of ropivacaine in Chinese patients by intra-articular administration after arthroscopic knee surgery, in order to assess the safety and efficacy. 21 ASA I-II patients received a single-dose of ropivacaine 150 mg in a 20 ml intra-articular injection at the end of surgery. Plasma samples were collected prior to and after ropivacaine administration. Plasma concentrations of ropivacaine were measured by HPLC. Pharmacokinetic parameters were calculated using noncompartmental analysis. Population pharmacokinetic modeling was performed to yield estimates of clearance, volume of distribution, and absorption rate constant. An analysis of covariates on the pharmacokinetic parameters was also carried out. Pain assessments were made using a verbal rating scale at intervals of 2, 4, 8, 12, 24, 36, 48 and 72 hours after surgery. The results show that the peak plasma concentrations occurred at an average of 0.93 ± 0.56 h (0.25 - 2 h), with a mean of 0.91 ± 0.4 mg/l (range 0.35 - 1.54 mg/l). The peak plasma concentrations and the times to reach the peak plasma concentration exhibited a marked variability among the subjects. All concentrations were well below the estimated toxic threshold (2.2 mg/l). No patient experienced adverse events that may have been related to ropivacaine administration. The intra-articular use of ropivacaine provided excellent control of pain after knee arthroscopy. Ropivacaine 150 mg provided satisfactory postoperative pain relief and can be safely administered by intraarticular injection in Chinese patients after arthroscopic knee surgery and the pharmacokinetic profiles of ropivacaine exhibited marked variability among the subjects. The high variability of pharmacokinetic profiles in this study may be caused by gender and body weight.

Case Scenario: Compartment Syndrome of the Forearm in Patient with an Infraclavicular Catheter

Case Scenario: Compartment Syndrome of the Forearm in Patient with an Infraclavicular Catheter

Pharmacokinetics of 450 mg ropivacaine with and without epinephrine for combined femoral and sciatic nerve block in lower extremity surgery. A pilot study

No pharmacokinetic data exist on doses of ropivacaine larger than 300 mg for peripheral nerve block in man, although in clinical practice higher doses are frequently used. The purpose of the present study was to describe the pharmacokinetic profile in serum of 450 mg ropivacaine with and without epinephrine in patients undergoing anterior cruciate ligament reconstruction. Twelve patients were randomly allocated to receive a single shot combined sciatic/femoral nerve block with 60 ml of either ropivacaine 0.75% alone (group R, n = 6) or ropivacaine 0.75% plus epinephrine 5 μg ml(-1) (group RE, n = 6). Venous blood samples for total and free ropivacaine serum concentrations were obtained during 48 h following block placement. Pharmacokinetic parameters were calculated using a non-compartmental approach. Results are given as mean (SD) for group R vs. group RE (95% CI of the difference). Total Cmax was 2.81 (0.94) μg ml(-1) vs. 2.16 (0.21) μg ml(-1) (95% CI -0.23, 1.53). tmax was 1.17 (0.30) h vs. 1.67 (0.94) h (95% CI -1.40, 0.40). The highest free ropivacaine concentration per patient was 0.16 (0.08) μg ml(-1) vs. 0.12 (0.04) μg ml(-1) (95% CI -0.04, 0.12). t(1/2) was 6.82 (2.26) h vs. 5.48 (1.69) h (95% CI -1.23, 3.91). AUC was 28.35 (5.92) μg ml(-1) h vs. 29.12 (7.34) μg ml(-1) h (95% CI -9.35, 7.81). Free serum concentrations of ropivacaine with and without epinephrine remained well below the assumed threshold of 0.56 μg ml(-1) for systemic toxicity. Changes in pharmacokinetics with epinephrine co-administration did not reach statistical significance.

Effect of local application of dexmedetomidine on the medium effective concentration of ropivacaine for brachial plexus block

Objective To investigate effect of local application of dexmedetomidine on the medium effective concentration (EC50) of ropivacaine for brachial plexus block and the mechanism of the analgesic effect induced by dexmedetomidine.Methods Fifty-two ASA Ⅰ or Ⅱ patients of both sexes,aged 18-50 yr,weighing 50-80 kg,scheduled for elective forearm or hand surgery,requiring ultrasound-guided axillary brachial plexus block,were randomly assigned into 2 groups (n =26 each):control group (group C) and dexmedetomidine group (group D).Axillary brachial plexus block was performed using only ropivacaine in group C.In group D the mixture of ropivacaine and 0.8 μg/kg dexmedetomidine was injected for the block.The effective block was defined as complete loss of pain sensation in the brachial plexus distribution.The volume of local anesthetics was 30 ml.The concentration of ropivacaine was determined by up-and-down technique.The initial concentration was 0.5 ％ and the ratio between the two successive concentrations was 1.2.If the block was effective,the next patient received a lower dose of ropivacaine,or if ineffective,a higher dose was given in the next patient.The EC50 and 95 ％ confidence interval of ropivacaine were determined using the Dixon-Massey method.Results The EC50 (95 ％ confidence interval) of ropivacaine was 0.32％ (0.30％-0.33％) in group D and 0.44％ (0.42％-0.46％) in group C.The EC50 of ropivacaine was significantly lower in group D than in group C (P ＜ 0.05).Conclusion Local application of dexmedetomidine can decrease the EC50 of ropivacaine for brachial plexus block guided by ultrasound,indicating that the mechanism of the analgesic effect induced by dexmedetomidine is related to the local anesthetic-like effect. Key words: Dexmedetomidine ; Amides ; Brachial plexus ; Nerve block ; Dose-response relationship, drug

Optimal effective concentration of ropivacaine for postoperative analgesia by single-shot femoral–sciatic nerve block in outpatient knee arthroscopy

To compare analgesic and mobility effects of different ropivacaine concentrations in femoral-sciatic nerve block, for postoperative analgesia in knee arthroscopy. Outpatients (American Society of Anesthesiologists physical classification status of I or II), scheduled for elective knee arthroscopy, were randomly allocated to one of seven groups, prospectively investigating different concentrations of ropivacaine (0.12%; 0.14%; 0.16%; 0.18%; 0.20%; 0.22% or 0.50%), for ultrasound-guided femoral-sciatic nerve block procedures for postoperative analgesia. Visual analogue scale (VAS) pain scores and motor block evaluation scales were observed at 4, 8, 16 and 24 h postsurgery. In total, 105 patients were enrolled; results were analysed for 103. VAS scores for the 0.12%, 0.14% and 0.16% groups were significantly different from the 0.50% group. There were no significant differences between the 0.18%, 0.20%, 0.22% and 0.50% groups: half maximal effective concentrations and 95% maximal effective concentrations of ropivacaine were 0.158 (95% confidence intervals [CI] 0.149, 0.167) and 0.198 (95% CI 0.186, 0.221), respectively. Rates of motor blockade (Bromage score or hip motor function scale > 0) were significantly different between the 0.50% group and all other ropivacaine doses. The 0.20% ropivacaine dose for femoral-sciatic nerve block in knee arthroscopy provided satisfactory postoperative analgesia, while preserving ability of motion.

A Randomized Comparison of Ropivacaine 0.1% and 0.2% for Continuous Interscalene Block After Shoulder Surgery

The optimal concentration of ropivacaine for continuous interscalene block after shoulder surgery is currently unknown. Fifty-six patients received a perineural infusion of either ropivacaine 0.1% or 0.2% for 48 hours after shoulder surgery. We assessed pain scores as primary end points and supplemental analgesia, ropivacaine consumption, motor block, side effects, and patient satisfaction as secondary end points. Pain scores were not statistically different during the infusion periods; however, supplemental analgesia consumption was higher in the group receiving ropivacaine 0.1% during the first 24 hours (64% vs 28%, P = 0.022). Other secondary end points were statistically inconclusive. These results suggest that ropivacaine 0.2% provides more effective analgesia than ropivacaine 0.1% during the first 24 hours for continuous interscalene block after shoulder surgery.

The Association of Interpleural Ropivacaine and Epidural Following Major Thoracic Surgery: A Randomised Clinical Trial Investigating Pharmocokinetics and Benefits

Background: Thoracic surgery is associated with high levels of postoperative pain. Interpleural blockades (IPB) can be effective in reducing this pain, but results after thoracotomy are controversial. The current study investigates the effects of the association of ropivacaine-based IPB and morphine epidurals after posterolateral thoracic surgery. Research Article British Journal of Medicine & Medical Research, 3(4): 841-854., 2013 842 Method: In this prospective, randomised, triple blind, placebo-controlled trial, patients received either intermittent ropivacaine IPB (R-group), (30 mg every 6 hours over 48 hours) or a placebo containing saline serum (P-group). The two groups had a morphine lumbar epidural. Pain was evaluated via patients’ reports and total morphine requirements. Results: 90 patients participated. There were no significant differences between levels of pain reported on mobilisation or morphine consumption between the two groups. For the principal criterion of VAS-A≥70 over the first 48 hours, this corresponds to a RR of 1.3(95%= 0.4-3.8). Patients in the R-group reported higher levels of pain at rest on day 2. The mean peak plasma concentrations of ropivacaine remained inferior to toxic plasma concentration levels. Conclusion: Postoperative interpleural infusions of 30 mg of ropivacaine every 6 hours in association with morphine epidurals are safe and feasible but do not improve postoperative experience of pain.

A comparison of epidural infusion of 0.2, 0.25, and 0.3% ropivacaine with fentanyl after unilateral total knee arthroplasty

A comparison of epidural infusion of 0.2, 0.25, and 0.3% ropivacaine with fentanyl after unilateral total knee arthroplasty

Epidural labor analgesia: A comparison of ropivacaine 0.125% versus 0.2% with fentanyl

Background: Minimum effective concentration of local anesthetics for providing optimal labor epidural analgesia and the strategies aiming to reduce their consumption are continuously being searched. Objectives: The objective of this study was to evaluate the efficacy of 0.125% and 0.2% ropivacaine both mixed with fentanyl 2 mcg/ml for epidural labor analgesia. Materials and Methods: A total of 80 parturients in active labor were randomly assigned to two groups of 40 each, to receive an epidural injection of 15 ml ropivacaine 0.125% with fentanyl (2 mcg/ml) in group R1 and 15 ml of ropivacaine 0.2% with fentanyl (2 mcg/ml) in group R2 as initial bolus dose. Same dose regimen was used as subsequent top-up dose on patients demand for pain relief. The duration and quality of analgesia, motor block, top-up doses required consumption of ropivacaine and fentanyl and feto-maternal outcome in both groups were compared. Results: Effective labor analgesia with no motor blockade was observed in both groups with no failure rate. Onset of analgesia was significantly faster in group R2 (75% parturients in 0-5 min) as compared to group R1 (25% parturients in 0-5 min), P 0.05), but consumption of fentanyl was significantly more in group R1 (54.00 ± 19.45) as compared to group R2 (31.50 ± 6.62), P Conclusion: We conclude that both the concentrations of ropivacaine (0.2% and 0.125%) with fentanyl are effective in producing epidural labor analgesia. However, 0.2% concentration was found superior in terms of faster onset, prolonged duration, lesser breakthrough pain requiring lesser top-ups, and hence a lesser consumption of opioids.

Epidural Anaesthesia with Goal-Directed Administration of Ropivacaine Improves Haemodynamic Stability when Combined with General Anaesthesia in Elderly Patients Undergoing Major Abdominal Surgery

The use of epidural ropivacaine may result in significant haemodynamic fluctuations during combined epidural and general anaesthesia. We designed this study to investigate whether epidural anaesthesia with a goal-directed approach, when combined with general anaesthesia, improved haemodynamic stability in elderly patients undergoing major abdominal surgery. Seventy-five elderly patients undergoing major abdominal surgery were randomly and evenly assigned to one of three groups receiving intraoperative epidural anaesthesia with either ropivacaine 0.1% (Group 1), ropivacaine 0.375% (Group 2) or ropivacaine 0.375% for abdominal wall pain and ropivacaine 0.1% for visceral pain (Group 3). General anaesthesia was induced using a target-controlled infusion of combined propofol and remifentanil. The remifentanil target concentration was adjusted according to the mean arterial pressure and heart rate, and vasoactive agents were administered to maintain stable haemodynamics. The need for vasoactive drug administrations was 1.4 (standard deviation 0.9) in Group 3 (n=24), representing a significantly lower frequency of administration compared with Groups 1 (n=24) and 2 (n=24) (P <0.05 versus Group 1; P <0.01 versus Group 2). The total intraoperative dose of remifentanil was significantly greater in Group 1 (P <0.01 versus Group 2; P <0.05 versus Group 3) but did not differ significantly between Groups 2 and 3. Goal-directed epidural anaesthesia with different ropivacaine concentrations can improve haemodynamic stability when combined with general anaesthesia for elderly patients undergoing major abdominal surgery.

Continuous paravertebral infusion of ropivacaine with or without fentanyl for pain relief in unilateral multiple fractured ribs

Background:Continuous thoracic paravertebral block (TPVB) provides effective analgesia for unilateral multiple fractured ribs (MFR). However, prolonged infusion of local anaesthetic (LA) in high doses can predispose to risk of LA toxicity, which may be reduced by using safer drugs or drug combinations. This study was conducted to assess efficacy and safety of paravertebral infusion of ropivacaine and adrenaline with or without fentanyl to provide analgesia to patients with unilateral MFR.Methods:Thirty adults, having ≥3 unilateral MFR, with no significant trauma outside chest wall, were studied. All received bolus of 0.5% ropivacaine 0.3 ml/kg through paravertebral catheter, followed by either 0.1-0.2 ml/kg/hr infusion of ropivacaine 0.375% with adrenaline 5 μg/ml in group RA or ropivacaine 0.2% with adrenaline 5 μg/ml and fentanyl 2 μg/ml in group RAF. Rescue analgesia was provided by IV morphine.Results:Statistical analysis was performed using unpaired Student t-test, Chi-square test and repeated measures ANOVA. After TPVB, VAS scores, respiratory rate and PEFR improved in both groups with no significant inter-group differences. Duration of ropivacaine infusion, morphine requirements, length of ICU and hospital stay, incidence of pulmonary complications and opioid-related side-effects were similar in both groups. Ropivacaine requirement was higher in group RA than group RAF. No patient showed signs of LA toxicity.Conclusion:Continuous paravertebral infusion of ropivacaine 0.375% with adrenaline 5 μg/ml at 0.1-0.2 ml/kg/hr provided effective and safe analgesia to patients with unilateral MFR. Addition of fentanyl 2 μg/ml allowed reduction of ropivacaine concentration to 0.2% without decreasing efficacy or increasing opioid-related side-effects.

Predictors of laterality of motor block during epidural analgesia in a mixed surgical population

Predictors of laterality of motor block during epidural analgesia are currently unknown, as studies so far have yielded conflicting results. We aimed to evaluate predictors of post-operative asymmetric lower extremity motor blockade in a mixed surgical population. This is a retrospective analysis of 578 consecutive patients with post-operative epidural analgesia for a variety of surgical procedures. A priori determined potential predictors of unilateral motor block were age, gender, body mass index, type of surgical procedure, vertebral level of puncture, catheter insertion depth into the epidural space and concentration of local anaesthetic. Logistic regression analysis was employed for evaluating predictors of laterality. Unilateral motor block occurred in 29.2% of the patients. Univariate logistic regression analysis showed that young age, female gender, gynaecologic procedures, a low puncture level, an increased depth of catheter insertion and a high ropivacaine concentration (2 mg/ml vs. less than 2 mg/ml) were significantly associated with increased incidence of laterality. Multivariate analysis revealed that age (OR = 0.73 per decade increase, P = 0.00001), the vertebral level of epidural puncture (OR = 1.37 per lowering vertebral level, P < 0.000001) and the depth of catheter insertion (OR = 1.46 per centimetre deeper, P = 0.001) were independent predictors of unilateral motor block. These results suggest that young patients with lumbar epidural analgesia or deep catheter insertion should be frequently monitored for the occurrence of laterality of motor block. Also, these results provide support for a prospective study to determine the optimal catheter insertion depth to decrease the risk of unilateral motor block.