The effect of Lidocaine on the viability of cultivated mature human cartilage cells: an in vitro study.

PURPOSE: More and more orthopedic procedures are performed in an outpatient setting. A commonly used strategy in pain management is the intra-articular injection of local anesthetics. Recent attention has been drawn to their possible toxic effect on chondrocytes. Local anesthetics, and in particular Lidocaine, are also used for diagnostic joint infiltrations. A controlled laboratory study was performed to investigate the possible toxic effect of Lidocaine on human articular chondrocytes. METHODS: Mature human articular chondrocytes were harvested from the knees of human tissue donors or patients undergoing total knee replacement. The cells were exposed to Lidocaine 1 and 2% with and without epinephrine and to a saline 0.9% control group, with variable exposure times in different experiments. The activity and viability of the cells were assessed by lactate dehydrogenase activity, interleukin-6 production and a live/dead cell count. RESULTS: After a 1-h exposure, devastating results were seen for Lidocaine 1, 2 and 2% with epinephrine showing cell death rates of 91, 99 and 97%, respectively, compared with 26% in the saline control group (P-values of 0.004, 0.010, 0.006, respectively). Exposing the chondrocytes to a 50/50 mixture of culture medium and local anesthetics substantially decreased cytotoxicity but still showed high toxicity when compared with the saline group (90% dead cells for Lidocaine 2%, P = 0.047). Lidocaine also showed a time-dependent cytotoxicity with gradually more dead cells after exposure for 15, 30 or 60 min. CONCLUSION: In vitro, local anesthetics containing Lidocaine are significantly more toxic to mature human articular chondrocytes than a saline 0.9% control group. The effect of Lidocaine on the viability of human chondrocytes in vivo needs further investigation. However, based on our in vitro results, cautious use of intra-articular Lidocaine in clinical practice is recommended.

Manual versus target-controlled infusion remifentanil administration in spontaneously breathing patients.

BACKGROUND: The combination of propofol-remifentanil for procedural deep sedation in spontaneously breathing patients is characterized by the frequent incidence of side effects, especially respiratory depression. These side effects may be due to either the drug combination or the drug delivery technique. Target-controlled infusion (TCI) might optimize drug delivery. In this prospective, randomized, double-blind study in patients undergoing elective colonoscopy, we thus tried to answer two questions: first, if adding remifentanil to propofol surpasses the disadvantages of the combination of these two products, and second, if administration of remifentanil via TCI decreases the incidence of side effects, compared to manually controlled administration. METHODS: Patients undergoing elective colonoscopy were randomly assigned to receive remifentanil via manually controlled continuous infusion (MCI) (0.125 microg x kg(-1) x min(-1) for 2 min followed by a continuous infusion of 0.05 microg x kg(-1) x min(-1)), TCI remifentanil (1 ng/mL), or placebo (normal saline either as TCI or manual infusion of equivalent rate). All patients received TCI propofol, adjusted to a target concentration level that provided deep sedation in which patients were not responsive to verbal commands, but maintained spontaneous ventilation without assistance. RESULTS: Significantly more patients in the placebo group showed movement, cough and hiccup, which transiently interfered with the examination. There were no clinically significant differences in hemodynamic or recovery variables among all groups. Remifentanil administered via TCI resulted in a decrease in propofol requirements. The incidence of hypopnea and apnea was less frequent when remifentanil was administered via TCI compared to MCI (TCI n = 7, MCI n = 16, P < 0.05). CONCLUSION: The combination of remifentanil and propofol for deep sedation in spontaneously breathing patients, offered better conditions for colonoscopy than propofol used as a single drug. Remifentanil administered via TCI resulted in a decrease in propofol dosing and in a lower incidence in apnea and respiratory depression (TCI n = 7, MCI n = 16, P < 0.05), compared to manually controlled administration of remifentanil.

Postoperative results after desflurane or sevoflurane combined with remifentanil in morbidly obese patients.

BACKGROUND: This randomized prospective study with blinded postanesthesia care unit (PACU) observers compared the recovery profiles in morbidly obese patients who received sevoflurane or desflurane for maintenance of anesthesia in combination with a remifentanil target controlled infusion (TCI). METHODS: 50 morbidly obese patients scheduled for laparoscopic gastric banding were included to receive BIS-guided sevoflurane or desflurane anesthesia with BIS-triggered inhalation boli in combination with remifentanil TCI. In the PACU, the following recovery scores were investigated: Modified Aldrete score, a modified Observers' Assessment of Alertness/Sedation Scale (OAA/S), pain numerical rating scale (NRS), oxygen saturation (SpO(2)) and postoperative nausea and vomiting (PONV). RESULTS: OAA/S and NRS pain scores showed a similar evolution in both groups from the moment of PACU admission up to 120 minutes after admission. In both groups, patients showed no serious hypoxemia during PACU stay. Incidence of PONV was shorter lasting in the sevoflurane group compared to the desflurane group. CONCLUSIONS: No clinically relevant difference was found in recovery in the PACU between morbidly obese patients anesthetized with desflurane or sevoflurane. Both agents resulted in satisfactory recovery in morbidly obese patients.

Remifentanil used to supplement propofol does not improve quality of sedation during spontaneous respiration.

STUDY OBJECTIVE: To evaluate whether the use of remifentanil to supplement propofol during spontaneous respiration confers any benefits in terms of quality of sedation and recovery, or in terms of reduction in propofol requirements. DESIGN: Prospective, randomized, double-blind study. SETTING: University hospital. PATIENTS: 50 ambulatory adult ASA physical status I and II patients scheduled for total colonoscopy. INTERVENTIONS: Patients were randomized to receive either propofol alone or propofol plus remifentanil 0.1 microg/kg/min, while independently maintaining spontaneous respiration. MEASUREMENTS: Cardiovascular and respiratory variables were measured before induction and at 1-minute intervals thereafter. Recovery from anesthesia was assessed using simple verbal commands and the Steward Post Recovery Score. Patient satisfaction was measured with a visual analog scale. Computer simulation was used to calculate the effect-site concentrations of propofol and remifentanil. MAIN RESULTS: The depressant effects on blood pressure and respiratory function were significantly higher when propofol and remifentanil were combined. Although the addition of remifentanil resulted in a decrease of propofol usage, recovery of anesthesia was faster and patient satisfaction was higher when using propofol alone. CONCLUSIONS: The addition of remifentanil to propofol during spontaneous ventilation offered no benefits compared with the use of propofol alone.

Ambulatory electrical external cardioversion with propofol or etomidate.

STUDY OBJECTIVE: To compare, in pairwise fashion, the effects of propofol and etomidate during ambulatory cardioversion and early recovery. DESIGN: Clinical, prospective, randomized, blinded, monocenter, pairwise, comparative study SETTING: OR and recovery area of the electrophysiological department, University Hospital Ghent, Belgium. PATIENTS: 34 patients with atrial arrhythmia who were scheduled for repetitive electrical cardioversion, of whom 25 patients completed the study. INTERVENTIONS: Nonpremedicated patients received during the first cardioversion either propofol (1 mg/kg) or etomidate (0.2 mg/kg) until loss of consciousness, followed by electrical external cardioversion. If after restoration of sinus rhythm for at least 1 day, atrial arrhythmia reoccurred, a second session was performed a week later, using the other induction drug. MEASUREMENTS: Systolic and diastolic blood pressure values taken before drug administration, at loss of consciousness, 60 seconds after cardioversion, and awake; the number of shocks, the total amount of energy, the number of patients in which we failed to restore sinus rhythm, the time before opening eyes, answering simple questions and be able to sit, were all noted. Aldrete scores and the Steward postanesthetic recovery scores were noted every minute until 10 minutes after the external cardioversion. Recovery tests were performed and evaluated 5, 10, 15, and 20 minutes after energy delivery. MAIN RESULTS: Number of shocks, amount of energy, and blood pressure values were comparable in both groups. Recovery times and Aldrete and Steward postanesthetic recovery scores showed a faster awakening in patients who were induced with propofol. Overall performance of the psychomotor test was better in the propofol group, and most pronounced at 10 and 15 minutes. CONCLUSIONS: Etomidate and propofol are both useful during ambulatory external electrical cardioversion. The described doses maintain stable hemodynamic conditions in nonpremedicated patients. Recovery scores and psychomotor test indicate a faster recovery in the propofol group. However, no intergroup differences were noted at 20 minutes after the cardioversion. A safe discharge of all patients from the critical care unit or postanesthesia care unit to the ward can be considered after 30 minutes.