“…Local anesthetic administered intravasally or in excessive doses can lead to toxic side effects on the cardiovascular and central nervous system, mimicking OI symptoms. Several studies 36–38 in TKA patients using identical ropivacaine doses to ours reported peak free ropivacaine concentrations well below previously proposed toxic thresholds. Previous studies investigating OI using no LIA 11,14,33 or LIA with bupivacaine 3,10 report similar incidences as ours.…”
Section: Discussionsupporting
confidence: 67%
“…Furthermore, there was no difference in bleeding nor perioperative fluid status between OT and OI or severe OI patients. Pre-and postoperative anemia is common in patients undergoing TKA 34 [36][37][38] in TKA patients using identical ropivacaine doses to ours reported peak free ropivacaine concentrations well below previously proposed toxic thresholds. Previous studies investigating OI using no LIA 11,14,33 or LIA with bupivacaine 3,10 report similar incidences as ours.…”
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 6 and 24 h 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 24 h 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 6 h. OI was associated with decreased orthostatic responses in systolic, diastolic, mean arterial pressures, and heart rate (all p < .05), while severe OI patients demonstrated impaired diastolic, mean arterial pressures, heart rate, and cardiac output responses (all p < .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.
“…Local anesthetic administered intravasally or in excessive doses can lead to toxic side effects on the cardiovascular and central nervous system, mimicking OI symptoms. Several studies 36–38 in TKA patients using identical ropivacaine doses to ours reported peak free ropivacaine concentrations well below previously proposed toxic thresholds. Previous studies investigating OI using no LIA 11,14,33 or LIA with bupivacaine 3,10 report similar incidences as ours.…”
Section: Discussionsupporting
confidence: 67%
“…Furthermore, there was no difference in bleeding nor perioperative fluid status between OT and OI or severe OI patients. Pre-and postoperative anemia is common in patients undergoing TKA 34 [36][37][38] in TKA patients using identical ropivacaine doses to ours reported peak free ropivacaine concentrations well below previously proposed toxic thresholds. Previous studies investigating OI using no LIA 11,14,33 or LIA with bupivacaine 3,10 report similar incidences as ours.…”
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 6 and 24 h 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 24 h 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 6 h. OI was associated with decreased orthostatic responses in systolic, diastolic, mean arterial pressures, and heart rate (all p < .05), while severe OI patients demonstrated impaired diastolic, mean arterial pressures, heart rate, and cardiac output responses (all p < .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.
“…Moreover, serum ropivacaine levels following high dosage PNB and local infiltration analgesia have in other studies been found to be below the potential level of toxicity 12‐14 . However, the risk of LAST should always be contemplated very carefully with all regional anaesthesia techniques.…”
Multimodal pain management first described in 1993 by Kehlet and Dahl 1,2 is established as the standard treatment of acute postoperative pain. Analgesic medications with different pharmacodynamic actions combined with regional anaesthesia techniques has been demonstrated to have a synergistic effect in ameliorating postoperative pain, promote early mobilization, reduce opioid consumption and limit overall side effects, especially through opioid-sparing effects. 3 The pharmacological elements of the multimodal analgesic regime may include: opioid analgesics (oxycodone, morphine, fentanyl etc), nonopioid systemic analgesics (acetaminophen, nonsteroidal anti-inflammatory drugs), adjuvants (gabapentin, ketamine, dexamethasone) and local anaesthetics (lidocaine, ropivacaine etc). Different treatment options have been investigated in the field of regional anaesthesia, including single-shot or continuous peripheral nerve blocks (PNB) and local infiltration analgesia. 4 Ultrasoundguided (USG) PNB have been documented to be a safe and effective method to reduce pain and opioid requirements in many clinical settings 5 and for many surgical procedures; ie both for upper and lower
“…In this study, the initial dose of ropivacaine for LIA was less than the maximal dose (225 mg) indicated by drug label [46], however, when combined with ACB bolus, the total dose (240 mg) of ropivacaine was slightly higher than recommended. However, previous studies have shown that injecting a much higher dose of ropivacaine in intra-articular LIA, than used in this study, is safe, with plasma levels below systemic toxic threshold [47–50]. Moreover, there was a 60 min interval between injections, which reduced plasma levels.…”
Background
Peripheral nerve block and local infiltration analgesia (LIA) provide good analgesia after knee replacement. This study evaluated the additional analgesic efficacy of continuous adductor canal block (ACB) added to single-dose LIA after medial unicondylar knee arthroplasty (UKA). We hypothesized ACB would lower pain scores and facilitate postoperative ambulation.
Methods
Forty-six patients were enrolled into this double-blind, randomized, placebo-controlled trial. UKA was performed and all patients received single-dose LIA intraoperatively. Patients were randomized into two groups: Group RP receiving 0.2% ropivacaine or Group Con receiving normal saline. A flow at 6 mL/h was administered for 48 h through a catheter in the adductor canal. Primary outcome was movement pain score at 24 h using the numeric rating scale (NRS-11). Secondary outcomes included serial postoperative pain scores, rate of patients with NRS>3 at rest and movement within 24 and 48 h postoperatively, time to breakthrough pain, quadriceps motor strength, ambulated distance, catheter related infection and patient satisfaction.
Results
Forty-two patients were analyzed. Pain scores with movement at 24 h postoperatively were significantly lower in Group RP than that in Group Con (3 vs. 5 NRS, P<0.001). Compared with Group Con, breakthrough pain occurred later in Group RP (18.5 vs 10.0 h,
P
= 0.002), serial pain scores at rest and with movement and rate of patients with NRS>3 with movement after surgery were significantly lower. Quadriceps motor strength was equivalent, however, ambulated distance on postoperative day 1 and 2 in Group Con was significant less (19.7 vs 37.3 m,
P
= 0.046; 33.4 vs 59.5 m,
P
= 0.002).
Conclusions
Continuous adductor canal block added to single-dose LIA offered better analgesia and facilitated ambulation without motor weakness after medial UKA.
Trial registration
Clinical Trial Registration:
ChiCTR-IOR-16008720
; Registered 25 June 2016.
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