Temperature of propofol does not reduce the incidence of injection pain

Clinical Study on the Combination of Transcutaneous Electrical Acupoint Stimulation and Lidocaine for Preventing Propofol Injection Pain

Purpose

Propofol is a widely used intravenous anesthetic in clinical practice. Lidocaine pretreatment is currently the most commonly used method to reduce the pain of propofol injection. However, propofol injection pain has not been eliminated and its incidence remains high. Transcutaneous electrical acupoint stimulation is a green therapy that combines transcutaneous electrical nerve stimulation therapy with the traditional acupuncture therapy of our motherland. This study investigated the effectiveness of transcutaneous electrical acupoint stimulation (TEAS) combined with lidocaine in preventing propofol injection pain and determined whether it can reduce postoperative complications and promote rapid postoperative recovery of patients.

Patients and Methods

A total of 220 women scheduled to undergo hysteroscopic surgery were enrolled in the study. The included patients were randomly divided into four groups of 55 patients each: normal saline group (group K), lidocaine group (group L), TEAS group (group T), and lidocaine + TEAS group (group L + T). Patients in group K received 2 mL saline (0.9% NaCl) pre-injection before anesthesia induction. Group L received 40 mg lidocaine pre-injection (2 mL of 2% lidocaine) before anesthesia induction. Group T received 30 min of transcutaneous electrical stimulation at bilateral election Hegu, Neiguan, and 2 mL saline pre-injections before anesthesia induction. Group L + T received TEAS and lidocaine pre-injection.

Results

The VAS scores and the four-point verbal rating scale of propofol injection were significantly different among the four groups. The prevalence of nausea, vomiting, abdominal pain, and abdominal distension after surgery among the four groups were statistically different. The bleeding days after surgery were significantly different among the four groups.

Conclusion

TEAS combined with lidocaine pre-injection reduced the incidence of propofol injection pain and significantly reduced patients’ pain levels compared with single lidocaine pre-injection. TEAS can also reduce the incidence of postoperative nausea and vomiting, abdominal pain, and abdominal distension, shorten postoperative bleeding days, and accelerate the postoperative recovery of patients.

Intravenous Dexmedetomidine Administration Prior Anesthesia Induction With Propofol at 4°C Attenuates Propofol Injection Pain: A Double-Blind, Randomized, Placebo-Controlled Trial

Background: Propofol injection pain, despite various interventions, still occurs during the anesthesia induction and causes intense discomfort and anxiety in patients. This study aimed to explore the effect of intravenous dexmedetomidine on propofol injection pain prior to anesthesia induction with propofol at 4°C.

Methods: A total of 251 patients (American Society of Anesthesiologists I–II) who underwent oral and maxillofacial surgery were randomly assigned to a combination group (n = 63), lidocaine group (n = 62), dexmedetomidine group (n = 63), and placebo-control group (n = 63); they received 0.5 ug/kg dexmedetomidine prior to anesthesia induction with propofol at 4°C, 40 mg lidocaine, 0.5 ug/kg dexmedetomidine prior to anesthesia induction, and normal saline, respectively. Incidence of pain, pain intensity, and reaction to the pain stimulus were evaluated by using verbal categorial scoring (VCS), a numerical rating scale (NRS), and the Surgical Pleth Index (SPI), respectively. In addition, hemodynamic parameters such as heart rate (HR) and mean arterial pressure (MAP) were also measured. The VCS and NRS were evaluated at 5 s after propofol injection. In addition, SPI, HR, and MAP were evaluated at three time points (before anesthesia induction and 5 and 30 s after propofol injection).

Results: The incidence of pain in the combination group (51%) was significantly lower than that in the lidocaine group (71%), dexmedetomidine group (67%), or placebo-control group (94%) (p < 0.001). VCS and NRS scores in the combination group were also lower compared with the other three groups (p < 0.001), with no statistically significant differences between the lidocaine group and dexmedetomidine group (p > 0.05). The SPI of the combination group decreased significantly in comparison with the other three groups at 5 s after propofol injection (F = 96.23, p < 0.001) and 30 s after propofol injection (F = 4.46, p = 0.005). Further comparisons between HR and MAP revealed no significant differences across the groups (p > 0.05).

Conclusion: Because of the sedative nature of dexmedetomidine and analgesic effect of low temperature, this study showed that intravenous dexmedetomidine prior to anesthesia induction with propofol at 4°C is highly effective in attenuating the incidence and severity of pain during injection compared with lidocaine (40 mg), dexmedetomidine 0.5 ug/kg) and placebo. This approach was not associated with any anesthesia complications.

Clinical Trial Registration:ClinicalTrials.gov, identifier: ChiCTR-2000034663

Prevention of propofol injection-related pain using pretreatment transcutaneous electrical acupoint stimulation

Background/aim: This study aimed to study the effect of pretreatment transcutaneous electrical acupoint stimulation (TEAS) in preventing propofol injection-related pain. Materials and methods: A total of 360 patients who were to undergo elective hysteroscopy surgery were randomly divided into the following three groups of 120 patients each: control (Group C), sham TEAS (Group F), and TEAS (Group T). Patients in Group C did not undergo any treatment before surgery; 30 min before the induction of anesthesia, patients in Groups F and T underwent electrical stimulation of the bilateral LI4-PC6 acupoint. Patients in Group F were subjected to 'feeling flow', while those in Group T were subjected to 'tolerance flow.' The stimulation frequency was 2/100 Hz and the duration of stimulation was 30 min. After the induction of anesthesia, propofol injection-related pain scores, hemodynamic parameters, and adverse reactions were recorded. Results: Of the 360 patients, 324 completed the study. There were significant differences among the groups in terms of the incidence of moderate-to-severe pain. In terms of the four-point scaling method, the end of the radial vein, the cubital vein, and the 'back of the hand' vein differed significantly among the three groups (P = 0.05). Finally, using a numerical rating scale, a significant difference was observed among the three groups in terms of the pain scores in the different veins. Conclusions: Pretreatment TEAS effectively reduces the incidence and severity of propofol injection-related pain, the incidence of postoperative nausea and vomiting, and patient postoperative pain scores.

Efficacy of methylprednisolone and lignocaine on propofol injection pain: A randomised, double-blind, prospective study in adult cardiac surgical patients

BACKGROUND AND AIMS

Propofol (2, 6-di-isopropylphenol) used for the induction of anaesthesia often causes mild to severe pain or discomfort on injection. We designed this double-blind study to compare the efficacy of methylprednisolone and lignocaine in reducing the pain of propofol injection in patients scheduled for cardiac surgery.

METHODS

A total of 165 adult patients, scheduled for elective cardiac surgery, were divided into three groups: saline (group S, n = 55), lignocaine 20 mg (Group L, n = 55) and methylprednisolone 125 mg diluted into 2 ml of distilled water (Group MP, n = 55). Drugs were administered after tourniquet application and occlusion was released after 1 min and 1/4^th of the total dose of propofol (2 mg/kg) was administered at the rate of 0.5 ml/s. Pain on propofol injection was evaluated by four-point verbal rating scale. Statistical methods used included Student's t-test and Chi-square test/Fisher's exact test.

RESULTS

The overall incidence of pain was 70.9% in the saline group, 30.9% in the lignocaine group and 36.4% in the methylprednisolone group. The intensity of pain was significantly less in patients receiving methylprednisolone and lignocaine than those receiving saline (P < 0.012).

CONCLUSION

Pre-treatment with intravenous methylprednisolone was found to be as effective as lignocaine in reducing propofol injection-induced pain.

Efficacy of the combination of cold propofol and pretreatment with remifentail on propofol injection pain

Background

Pain upon the injection of propofol is a common adverse effect. This study was conducted to evaluate the analgesic effect of remifentanil and cold propofol during propofol injection for the induction of anesthesia and to determine if a combination of cold propofol and remifentanil produced additional analgesic efficacy.

Methods

A total of 160 patients aged 20-65 years old were randomly allocated into one of four groups (n = 40, in each). Control and remifentanil group patients received 2 mg/kg propofol that had been stored at room temperature (20-23℃), while the cold and combination group received cold (4℃) propofol. The patients received remifentanil 0.5 µg/kg IV in the remifentanil and combination groups or saline in the control and cold groups. Ninety seconds after administration the patients were administered propofol over a 30 second period. The pain intensity and incidence were then evaluated using a 4-point verbal rating scale.

Results

The incidence of pain was significantly reduced in groups that received remifentanil in the cold and combination groups when compared with the control group (27.5%, 30%, and 2.5% vs. 70%, respectively). Moreover, the severity of pain was significantly lower in groups that received remifentanil in the cold and combination groups when compared with the control group. The incidence and severity of pain from the propofol injection in the combination group was significantly lower than that in the remifentanil and cold groups.

Conclusions

The combination of cold propofol and pretreatment with remifentanil more effectively reduced the incidence of pain upon the injection of propofol than either treatment alone.

Prevention of pain on injection with propofol: a quantitative systematic review

The best intervention to prevent pain on injection with propofol is unknown. We conducted a systematic literature search (Medline, Embase, Cochrane Library, bibliographies, hand searching, any language, up to September 1999) for full reports of randomized comparisons of analgesic interventions with placebo to prevent that pain. We analyzed data from 6264 patients (mostly adults) of 56 reports. On average, 70% of the patients reported pain on injection. Fifteen drugs, 12 physical measurements, and combinations were tested. With IV lidocaine 40 mg, given with a tourniquet 30 to 120 s before the injection of propofol, the number of patients needed to be treated (NNT) to prevent pain in one who would have had pain had they received placebo was 1.6. The closest to this came meperidine 40 mg with tourniquet (NNT 1.9) and metoclopramide 10 mg with tourniquet (NNT 2.2). With lidocaine mixed with propofol, the best NNT was 2.4; with IV alfentanil or fentanyl, it was 3 to 4. IV lidocaine before the injection of propofol was less analgesic. Temperature had no significant effect. There was a lack of data for all other interventions to allow meaningful conclusions. The diameter of venous catheters and speed of injection had no impact on pain.

IMPLICATIONS

IV lidocaine (0.5 mg/kg) should be given with a rubber tourniquet on the forearm, 30 to 120 s before the injection of propofol; lidocaine will prevent pain in approximately 60% of the patients treated in this manner.