Nitrous oxide/oxygen mixture and the prevention of pain during injection of propofol

Lidocaine for reducing propofol-induced pain on induction of anaesthesia in adults

BACKGROUND

Pain on propofol injection is an untoward effect and this condition can reduce patient satisfaction. Intravenous lidocaine injection has been commonly used to attenuate pain on propofol injection. Although many studies have reported that lidocaine was effective in reducing the incidence and severity of pain, nevertheless, no systematic review focusing on lidocaine for preventing high-intensity pain has been published.

OBJECTIVES

The objective of this review was to determine the efficacy and adverse effects of lidocaine in preventing high-intensity pain on propofol injection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 10), Ovid MEDLINE (1950 To October 2014), Ovid EMBASE (1988 to October 2014), LILACS (1992 to October 2014) and searched reference lists of articles.We reran the search in November 2015. We found 11potential studies of interest, those studies were added to the list of 'Studies awaiting classification' and will be fully incorporated into the formal review findings when we update the review.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) using intravenous lidocaine injection as an intervention to decrease pain on propofol injection in adults. We excluded studies without a placebo or control group.

DATA COLLECTION AND ANALYSIS

We collected selected studies with relevant criteria. We identified risk of bias in five domains according to the following criteria: random sequence generation, allocation concealment, adequacy of blinding, completeness of outcome data and selective reporting. We performed meta-analysis by direct comparisons of intervention versus control. We estimated the summary odds ratios (ORs) and 95% confidence intervals using the random-effects Mantel-Haenszel method in RevMan 5.3. We used the I(2) statistic to assess statistical heterogeneity. We assessed overall quality of evidence using the GRADE approach.

MAIN RESULTS

We included 87 studies, 84 of which (10,460 participants) were eligible for quantitative analysis in the review. All participants, aged 13 years to 89 years, were American Society of Anesthesiologists (ASA) I-III patients undergoing elective surgery. Each study was conducted in a single centre in high- , middle- and low-income countries worldwide. According to the risk of bias assessment, all except five studies were identified as being of satisfactory methodological quality, allowing 84 studies to be combined in the meta-analysis. Five of the 84 studies were assessed as high risk of bias: one for participant and personnel blinding, one for incomplete outcome data, and three for other potential sources of bias.The overall incidence of pain and high-intensity pain following propofol injection in the control group were 64% (95% CI 60% to 67.9%) and 38.1% (95% CI 33.4% to 43.1%), respectively while those in the lidocaine group were 30.2% (95% CI 26.7% to 33.7%) and 11.8% (95% CI 9.7% to 13.8%). Both lidocaine admixture and pretreatment were effective in reducing pain on propofol injection (lidocaine admixture OR 0.19, 95% CI 0.15 to 0.25, 31 studies, 4927 participants, high-quality evidence; lidocaine pretreatment OR 0.13, 95% CI 0.10 to 0.18, 43 RCTs, 4028 participants, high-quality evidence). Similarly, lidocaine administration could considerably decrease the incidence of pain when premixed with the propofol (OR 0.19, 95% CI 0.15 to 0.24, 36 studies, 5628 participants, high-quality evidence) or pretreated prior to propofol injection (OR 0.14, 95% CI 0.11 to 0.18, 52 studies, 4832 participants, high-quality evidence). Adverse effects of lidocaine administration were rare. Thrombophlebitis was reported in only two studies (OR not estimated, low-quality evidence). No studies reported patient satisfaction.

AUTHORS' CONCLUSIONS

Overall, the quality of the evidence was high. Currently available data from RCTs are sufficient to confirm that both lidocaine admixture and pretreatment were effective in reducing pain on propofol injection. Furthermore, there were no significant differences of effect between the two techniques.

Effect of nitrous oxide inhalation on pain after propofol and rocuronium injection

PURPOSE

This prospective, double-blind, placebo-controlled study was designed to determine the efficacy of nitrous oxide (N(2)O) in alleviating the pain that followed sequential injection of propofol and rocuronium.

METHODS

A total of 205 adult patients (age, 18-68 years) received one of the following combinations: NaCl and 100 % O(2) (group C); 0.5 mg/kg lidocaine and 100 % O(2) (group L); NaCl and a mixture of 67 % N(2)O/O(2) (group N); or 0.5 mg/kg lidocaine and a mixture of 67 % N(2)O/O(2) (group LN). Vein occlusion was released after 1 min, and 5 ml propofol was injected over 10 s. Pain was evaluated on a visually enlarged, laminated, numeric rating (0-10) scale. The remainder of the induction dose of propofol (with a 3-ml bolus of normal saline and 0.6 mg/kg rocuronium) was then injected. The response to the rocuronium injection was assessed with a four-point scale (0-3).

RESULTS

The incidence and severity of pain from the propofol injection in groups L, N, and LN were significantly lower than those in group C (P < 0.001). Frequency and intensity of the withdrawal response were significantly less in groups N and LN than in groups C and L (no response, P < 0.001; severe response, P < 0.001).

CONCLUSIONS

Pretreatment with inhaled N(2)O can reduce the pain associated with propofol and rocuronium injection. Moreover, N(2)O (with or without lidocaine) is more effective than lidocaine alone in reducing rocuronium-related withdrawal reactions associated with sequential injection of propofol and rocuronium.

Effect of nitrous oxide on pain due to rocuronium injection: A randomised, double-blind, controlled clinical trial

A prospective, randomised, double-blind, placebo-controlled study was carried out to determine the effect of nitrous oxide (N₂O) on the frequency and severity of pain and withdrawal reactions after injection of rocuronium. Eighty ASA physical status I and II patients undergoing general anaesthesia for elective surgery were enrolled. The patients were randomised to receive 100% oxygen (O₂), or 50% N₂O in O₂ for 3 minutes followed by a subparalysing dose of rocuronium 0.06 mg/kg. After induction of anaesthesia with thiopentone 5 mg/kg, an intubating dose of rocuronium 0.6 mg/kg was given. The patients were observed after injection of rocuronium 0.06 mg/kg, and asked to rate pain in the arm on a 4-point (0–3) verbal rating scale (none, mild, moderate or severe). After the intubating dose of rocuronium, withdrawal reactions were recorded. Thirty-six patients (90%) in the group N₂O and 15 patients (37.5%) in the group O₂ reported no pain (P < 0.001). The pain was mild in 1 (2.5%) and 9 (22.5%) patients in N₂O and O₂ groups, respectively (P = 0.006). Moderate pain occurred in 2 (5%) patients in group N₂O and 15 (37.5%) patients in group O₂ (P = 0.001). Severe pain was reported by one patient in each group (P = 0.47). Withdrawal response after an intubating dose of rocuronium was observed in 6 (15%) and 18 (45%) patients in the N₂O and O₂ groups, respectively (P < 0.05). Inhalation of 50% N₂O in O₂ reduces the incidence and severity of pain and the withdrawal reactions associated with rocuronium injection.