Population pharmacokinetics of ropivacaine used for local infiltration anaesthesia during primary total unilateral and simultaneous bilateral knee arthroplasty

Effects of a Modified Long-Acting Cocktail on Analgesia and Enhanced Recovery After Total Hip Arthroplasty: A Double-Blinded Randomized Clinical Trial

BACKGROUND

We compared the efficacy and safety of a modified cocktail for postoperative analgesia and early functional rehabilitation in patients undergoing total hip arthroplasty (THA).

METHODS

Magnesium sulfate and sodium bicarbonate were added to a cocktail of ropivacaine, epinephrine, and dexamethasone. Primary outcome measures were visual analog scale (VAS) pain scores at various intervals after surgery, morphine consumption for rescue analgesia after surgery, and time to first rescue analgesia. Secondary outcomes were hip function after surgery, daily walking distance, quadriceps muscle strength, and the incidence of postoperative adverse reactions.

RESULTS

Morphine consumption was significantly lower in the modified cocktail group than in the control group in the first 24 hours after surgery (6.2 ± 6.0 versus 14.2 ± 6.4 mg, P < .001), as was total morphine consumption (10.0 ± 8.6 versus 19.2 ± 10.1 mg, P < .001). The duration of the first rescue analgesia was significantly prolonged (23.7 ± 10.3 versus 11.9 ± 5.8 mg, P < .001). Morphine consumption was also reduced in the magnesium sulfate and sodium bicarbonate groups over a 24-hour period compared to the control group (P < .001). The modified cocktail group had significantly lower resting VAS pain scores than the control group within 24 hours after surgery (P < .050). The VAS pain scores during movement within 12 hours after surgery were also lower (P < .050). The experimental groups showed better hip range of motion (P < .050) and longer walking distance (P < .050) on the first postoperative day, and levels of inflammatory markers were significantly reduced. The incidence of postoperative adverse reactions was similar among the 4 groups.

CONCLUSIONS

The modified cocktail with a new adjuvant can prolong the duration of postoperative analgesia, reduce the dosage of rescue analgesics, and accelerate early postoperative functional recovery in patients undergoing THA.

Postoperative orthostatic intolerance following fast-track unicompartmental knee arthroplasty: incidence and hemodynamics-a prospective observational cohort study

BACKGROUND

Early postoperative mobilization is essential for early functional recovery but can be inhibited by postoperative orthostatic intolerance (OI). Postoperative OI is common after major surgery, such as total knee arthroplasty (TKA). However, limited data are available after less extensive surgery, such as unicompartmental knee arthroplasty (UKA). We, therefore, investigated the incidence of OI as well as cardiovascular and tissue oxygenation responses during early mobilization after UKA.

METHODS

This prospective single-centre observational study included 32 patients undergoing primary UKA. Incidence of OI and cardiovascular and tissue oxygenation responses during mobilization were evaluated preoperatively, at 6 and 24 h after surgery. Perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain during mobilization and opioid usage were recorded.

RESULTS

During mobilization at 6 h after surgery, 4 (14%, 95%CI 4-33%) patients experienced OI; however, no patients terminated the mobilization procedure prematurely. Dizziness and feeling of heat were the most common symptoms. OI was associated with attenuated systolic and mean arterial blood pressure responses in the sitting position (all p < 0.05). At 24 h after surgery, 24 (75%) patients had already been discharged, including three of the four patients with early OI. Only five patients were available for measurements, two of whom experienced OI; one terminated the mobilization procedure due to intolerable symptoms. We observed no statistically significant differences in perioperative fluid balance, bleeding, surgery duration, postoperative hemoglobin, pain, or opioid usage between orthostatic intolerant and tolerant patients.

CONCLUSIONS

The incidence of orthostatic intolerance after fast-track unicompartmental knee arthroplasty is low (~ 15%) and is associated with decreased orthostatic pressure responses. Compared to the previously described orthostatic intolerance incidence of ~ 40% following total knee arthroplasty, early orthostatic intolerance is uncommon after unicompartmental knee arthroplasty, suggesting a procedure-specific component.

TRIAL REGISTRATION

Prospectively registered at ClinicalTrials.gov; registration number: NCT04195360, registration date: 13.12.2019.

Comparison of metabolic rates of ropivacaine in cerebrospinal fluid as inferred from plasma concentrations between elderly patients and young patients

BACKGROUND

With the aging of human society, more and more elderly patients have to undergo surgery and anesthesia. Clinical observations have indicated from time to time that spinal anesthesia in the elderly appears to last longer than in young people, although there is limited research in this area and the mechanism is unclear at present time. This research work is expected to help understand the decline of local anesthetic metabolism in cerebrospinal fluid of elderly patients so as to help them with precise anesthesia and rapid rehabilitation.

METHODS

Twenty patients with spinal anesthesia in orthopedic lower limb surgery were selected to study the rate of drug metabolism in cerebrospinal fluid in two age groups, i.e.,18-30 years old and 75-90 years old. Ropivacaine in peripheral blood is used as a probe to reflect the speed of drug metabolism in cerebrospinal fluid. The contents of total Aβ protein and hyaluronic acid in the cerebrospinal fluid were investigated as well.

RESULTS

The equivalent dose of ropivacaine anesthetizes the elderly group for a longer time. The metabolism rate of ropivacaine in an elderly patient was slower than that of a young patient. No significant difference in total Aβ protein between the two groups was observed while hyaluronic acid in the elderly group was significantly higher than that in the young group.

CONCLUSIONS

This study shows that the dose of ropivacaine should be reduced when used for anesthesia in elderly patients. The cumulation of ropivacaine and HA appears to imitate the degeneration of central lymphatic circulation metabolism in elderly people.

Systemic Ropivacaine Concentrations Following Local Infiltration Analgesia and Femoral Nerve Block in Older Patients Undergoing Total Knee Arthroplasty

Purpose

The study examined the pharmacokinetic profile of fixed formulation mixtures comprising 225 mg of ropivacaine for local infiltration analgesia with or without epinephrine, and femoral nerve block in older patients presenting for orthopedic surgery and explored potential influences of block type, age, and body weight on this profile.

Patients and Methods

Twenty four patients scheduled for total knee arthroplasty were randomly assigned to three groups: femoral nerve block, local infiltration analgesia with epinephrine and local infiltration analgesia without epinephrine. Blood samples were collected at 10, 30, 60, and 120 min following the block and total plasma concentrations of ropivacaine were quantified by high performance liquid chromatography.

Results

The mean individual peak total plasma concentrations of ropivacaine in local infiltration analgesia with and without epinephrine, and femoral nerve block group were 0.334, 0.490 and 0.545 μg mL-1 (p = 0.16). Local infiltration with epinephrine group had significantly lower plasma ropivacaine concentrations at 30, 60 and 120 minutes. The plasma ropivacaine concentrations exceeded 2.2 μg mL-1 in one patient. Age, but not body weight, had a moderate correlation with peak plasma ropivacaine concentration (r = 0.37, p = 0.08).

Conclusion

Administration of a fixed 225 mg dose of ropivacaine for local infiltration analgesia with epinephrine and femoral nerve block results in plasma ropivacaine concentrations below the toxicity threshold, indicating their safety. The use of local infiltration analgesia with epinephrine provides a greater safety margin, as local infiltration analgesia without epinephrine may lead to ropivacaine concentrations associated with symptoms of local anesthetic toxicity.

Safety and efficacy of intraosseous ropivacaine in lower extremity (SORE) study

BACKGROUND

Day stay surgery for anterior cruciate ligament (ACL) reconstructions is an increasingly common practice and has driven clinicians to develop postoperative pain regimes that allow same day mobilization and a safe and timely discharge. There is a paucity of literature surrounding the use of intraosseous (IO) ropivacaine used as a Bier's block to provide both intraoperative and postoperative analgesia in lower limb surgery.

METHODS

This patient blinded, pilot study randomized 15 patients undergoing ACL reconstruction to receive either IO ropivacaine 1.5 or 2.0 mg/kg; or 300 mg of ropivacaine as local infiltration. The primary outcome for this study was arterial plasma concentration of ropivacaine. Samples were taken via an arterial line at prespecified times after tourniquet deflation. Secondary outcomes included immediate postoperative pain scores using the visual analogue scale and perioperative opioid equivalent consumption.

RESULTS

All patients in the intervention group receiving IO ropivacaine had plasma concentrations well below the threshold for central nervous system (CNS) toxicity (0.60 μg/mL). The highest plasma concentration was achieved in the intervention group receiving 1.5 mg/kg dose of ropivacaine reaching 2.93 mg/mL. This would equate to 0.18 μg/mL of free plasma ropivacaine. There were no differences across the three groups regarding pain scores or perioperative opioid consumption.

CONCLUSIONS

This study demonstrates that IO ropivacaine is both safe and effective in reducing perioperative pain in patients undergoing ACL reconstruction. There may be scope to increase the IO dose further or utilize other analgesics via the IO regional route to improve perioperative pain relief.

Pain management after total knee arthroplasty: PROcedure SPEcific Postoperative Pain ManagemenT recommendations

BACKGROUND

The PROSPECT (PROcedure SPEcific Postoperative Pain ManagemenT) Working Group is a global collaboration of surgeons and anaesthesiologists formulating procedure-specific recommendations for pain management after common operations. Total knee arthroplasty (TKA) is associated with significant postoperative pain that is difficult to treat. Nevertheless, pain control is essential for rehabilitation and to enhance recovery.

OBJECTIVE

To evaluate the available literature and develop recommendations for optimal pain management after unilateral primary TKA.

DESIGN

A narrative review based on published systematic reviews, using modified PROSPECT methodology.

DATA SOURCES

A literature search was performed in EMBASE, MEDLINE, PubMed and Cochrane Databases, between January 2014 and December 2020, for systematic reviews and meta-analyses evaluating analgesic interventions for pain management in patients undergoing TKA.

ELIGIBILITY CRITERIA

Each randomised controlled trial (RCT) included in the selected systematic reviews was critically evaluated and included only if met the PROSPECT requirements. Included studies were evaluated for clinically relevant differences in pain scores, use of nonopioid analgesics, such as paracetamol and nonsteroidal anti-inflammatory drugs and current clinical relevance.

RESULTS

A total of 151 systematic reviews were analysed, 106 RCTs met PROSPECT criteria. Paracetamol and nonsteroidal anti-inflammatory or cyclo-oxygenase-2-specific inhibitors are recommended. This should be combined with a single shot adductor canal block and peri-articular local infiltration analgesia together with a single intra-operative dose of intravenous dexamethasone. Intrathecal morphine (100 μg) may be considered in hospitalised patients only in rare situations when both adductor canal block and local infiltration analgesia are not possible. Opioids should be reserved as rescue analgesics in the postoperative period. Analgesic interventions that could not be recommended were also identified.

CONCLUSION

The present review identified an optimal analgesic regimen for unilateral primary TKA. Future studies to evaluate enhanced recovery programs and specific challenging patient groups are needed.

The Effects of Periarticular Injection Cocktail in Postoperative Analgesia after Bilateral Unicompartmental Knee Arthroplasty

Objective

This study was conducted to compare postoperative pain and functional recovery in bilateral unicompartmental knee arthroplasty (UKA) and unilateral UKA after cocktail therapy.

Methods

A total of 240 patients who received unilateral UKA and bilateral UKA in our orthopedic department from February 2019 to April 2020 were collected. The general clinical data was recorded and compared between the two groups of subjects, and the time of postoperative landing was recorded separately for both groups. A visual analogue scale (VAS) was used to record the patients' pain at 1, 7, and 14 days postoperatively, as well as the range of motion of the affected limb at 1, 7, 14 days, and 3 months postoperatively and the hospital for special surgery (HSS) knee score of the knee at 1 month postoperatively.

Results

After cocktail injection analgesia, unilateral patients with knee surgery got off the ground and walked significantly earlier than patients with bilateral surgery, while there was no significant difference between the two groups in terms of pain at 1, 7, and 14 days after surgery, range of motion of the affected limb at 1, 7, 14 days, and 3 months after surgery, and knee HSS score at 1 month after surgery.

Conclusion

Periarticular cocktail injection significantly reduces postoperative pain in patients, and bilateral UKA surgery can be used as satisfactory as unilateral UKA in clinical practice.

Orthostatic intolerance after fast-track knee arthroplasty: Incidence and hemodynamic pathophysiology

BACKGROUND

Early postoperative mobilization can be hindered by orthostatic intolerance (OI) due to failed orthostatic cardiovascular regulation. The underlying mechanisms are not fully understood and specific data after total knee arthroplasty (TKA) are lacking. Therefore, we evaluated the incidence of OI and the cardiovascular response to mobilization in fast-track TKA.

METHODS

This prospective observational cohort study included 45 patients scheduled for primary TKA in spinal anesthesia with a multimodal opioid-sparing analgesic regime. OI and the cardiovascular response to sitting and standing were evaluated with a standardized mobilization procedure preoperatively, and at 6h and 24h postoperatively. Hemodynamic variables were measured non-invasively (LiDCO™ Rapid). Perioperative bleeding, fluid balance, surgery duration, postoperative hemoglobin, opioid use and pain during mobilization were recorded.

RESULTS

Eighteen (44%) and 8 (22%) patients demonstrated OI at 6 and 24h after surgery respectively. Four (10%) and 2 (5%) patients experienced severe OI and terminated the mobilization procedure prematurely. Dizziness was the most common OI symptom during mobilization at 6h. OI was associated with decreased orthostatic responses in systolic, diastolic, mean arterial pressures and heart rate (all p<0.05), while severe OI patients demonstrated impaired diastolic, mean arterial pressures, heart rate and cardiac output responses (all p<0.05). No statistically significant differences in perioperative bleeding, fluid balance, surgery duration, postoperative hemoglobin, pain or opioid use were observed between orthostatic tolerant and intolerant patients.

CONCLUSION

Early postoperative OI is common following fast-track TKA. Pathophysiologic mechanisms include impaired orthostatic cardiovascular responses. The progression to severe OI symptoms appears to be primarily due to inadequate heart rate response.

The ethics of quality improvement studies: do the needs of the many outweigh the needs of the few?

Clinical research involving human subjects and quality improvement (QI) projects share a common goal of seeking to improve human health, whether by directly changing the standard of care (research) or by improving the process(es) by which that care is delivered (QI). Whether a QI project requires informed consent (written or oral) is a function of the risk-benefit analysis of the study; such a determination should not be at the sole discretion of the investigators, but should come from an appropriately constituted review board with expertise in the ethics of biomedical research.