Day-case anaesthesia for termination of pregnancy. Evaluation of a total intravenous anaesthetic technique

Local anaesthesia for pain control in first trimester surgical abortion

BACKGROUND

Abortions prior to 14 weeks are among the most common outpatient surgical procedures performed on people capable of becoming pregnant. Various methods have been used to control pain; however, many people still experience pain with the procedure.

OBJECTIVES

To evaluate the benefits and harms of local anaesthesia given for pain control during surgical abortion at less than 14 weeks' gestation.

SEARCH METHODS

We searched CENTRAL (Ovid EBM Reviews), MEDLINE (Ovid), Embase, POPLINE, and Google Scholar to December 2022 for randomized controlled trials of pain control in surgical abortion at less than 14 weeks' gestation using suction aspiration. We searched the reference lists of related reviews and articles.

SELECTION CRITERIA

We selected effectiveness and comparative effectiveness randomized controlled trials that studied local anaesthesia with common local anaesthetics and administration routes given for pain control in surgical abortion at less than 14 weeks' gestation using uterine aspiration. Outcomes included intraoperative pain, patient satisfaction, and adverse events.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. We computed mean differences (MD) with 95% confidence intervals (CI) for continuous variables reporting a mean. We assessed the certainty of evidence using GRADE.

MAIN RESULTS

Thirteen studies with 1992 participants met the inclusion criteria. Due to heterogeneity of interventions, we could not pool more than two studies for any outcome. We used 13 mm improvement on a visual/verbal analogue scale to indicate a clinically meaningful difference in pain with surgical abortion (pain with dilation, aspiration, or during procedure). Based on type of pain control, we divided studies into three groups. Paracervical block (PCB) effectiveness trials A 20 mL 1% lidocaine PCB reduced pain with dilation (MD -37.00, 95% CI -45.64 to -28.36), and aspiration (MD -26.00, 95% CI -33.48 to -18.52) compared to a sham PCB (1 RCT, 120 participants; high-certainty evidence). A PCB with 14 mL of 1% chloroprocaine resulted in a slight reduction in pain with aspiration compared to a PCB with normal saline injected at two or four sites (MD -1.50, 95% CI -2.45 to -0.55; 1 RCT, 79 participants; high-certainty evidence). PCB comparative effectiveness trials An ultracaine PCB probably results in little to no clinically meaningful difference in pain during procedure compared to topical cervical lidocaine spray (median 1 point higher, interquartile range (IQR) 0 to 3; P < 0.001; 1 RCT, 48 participants; moderate-certainty evidence). A 1000 mg dose of intravenous paracetamol probably does not decrease pain as much as ultracaine PCB during procedure (median 2 points higher, IQR 1 to 3; P < 0.001; 1 RCT, 46 participants; moderate-certainty evidence). Various local anaesthetics in PCB comparative effectiveness trials A 10 mL buffered 2% lidocaine PCB probably does not result in a clinically meaningful difference in pain with dilation compared to a plain lidocaine PCB (MD -0.80, 95% CI -0.89 to -0.71; 1 RCT, 167 participants; moderate-certainty evidence). A buffered lidocaine PCB probably does not result in a clinically meaningful difference in pain with aspiration compared to plain lidocaine PCB (MD -0.57, 95% CI -1.01 to -0.06; 2 RCTs, 291 participants; moderate-certainty evidence). Non-PCB local anaesthesia or PCB technique effectiveness trials PCB: waiting versus no waiting Waiting three to five minutes between 1% lidocaine PCB injection and dilation probably does not result in a clinically meaningful difference in pain with dilation compared to not waiting (MD -0.70, 95% CI -1.23 to -0.17; 2 RCTs, 357 participants; moderate-certainty evidence). Topical cervical analgesia Topical 10 mL 2% lignocaine gel probably does not result in a clinically meaningful difference in pain with aspiration compared to KY Jelly (MD -0.87, 95% CI -1.60 to -0.14; 1 RCT, 131 participants; moderate-certainty evidence). In participants who also received a PCB, 20 mg topical cervical lidocaine spray probably does not result in a clinically meaningful difference in pain during the procedure compared to two pumps of normal saline spray (median -1 point, IQR -2 to -1; P < 0.001; 1 RCT, 55 participants; moderate-certainty evidence). Intravenous paracetamol 1000 mg compared to two pumps of cervical lidocaine spray probably does not results in a clinically meaningful difference in pain procedure (median 1 point, IQR -2 to 2; P < 0.001; 1 RCT, 48 participants; low-certainty evidence). Non-PCB local anaesthesia or PCB technique comparative effectiveness trials Depth of PCB The evidence suggests that a 3-cm deep PCB probably does not result in a clinically meaningful difference in pain with aspiration compared to a 1.5-cm deep PCB (MD -1.00, 95% CI -1.09 to -0.91; 2 RCTs, 229 participants; low-certainty evidence). PCB: four sites versus two sites A two-site (4-8 o'clock) 20 mL 1% lidocaine PCB does not result in a clinically meaningful difference in pain with dilation compared to a four-site (2-4-8-10 o'clock) PCB (MD 8.60, 95% CI 0.69 to 16.51; 1 RCT, 163 participants; high-certainty evidence). Overall, participants reported moderately high satisfaction with pain control and studies reported few adverse events.

AUTHORS' CONCLUSIONS

Evidence from this updated review indicates that a 20 mL 1% plain lidocaine PCB decreases pain during an abortion procedure. Evidence supports forgoing buffering lidocaine and a wait time between PCB injection and cervical dilation. A 1.5-cm deep injection as opposed to a 3-cm deep injection is sufficient. A two-site PCB injection as opposed to a four-site injection has similar effectiveness. Topical cervical anaesthesia (10 mL 2% lignocaine gel or 20 mg topical cervical lidocaine spray) as compared to placebo did not decrease pain based on moderate-certainty evidence, but then when compared to PCB, pain control was similar. Due to this inconsistency in evidence regarding the effectiveness of topical anaesthesia, its routine use is presently not supported. This review did not include studies of pain management with conscious sedation but, based on the results of our prior Cochrane review and the 2022 WHO guidelines, we recommend that the option of combination of pain management using conscious sedation plus PCB and non-steroidal anti-inflammatory drugs should be offered where conscious sedation is available as it further decreases pain.

Nitrous oxide-based techniques versus nitrous oxide-free techniques for general anaesthesia

BACKGROUND

Nitrous oxide has been used for over 160 years for the induction and maintenance of general anaesthesia. It has been used as a sole agent but is most often employed as part of a technique using other anaesthetic gases, intravenous agents, or both. Its low tissue solubility (and therefore rapid kinetics), low cost, and low rate of cardiorespiratory complications have made nitrous oxide by far the most commonly used general anaesthetic. The accumulating evidence regarding adverse effects of nitrous oxide administration has led many anaesthetists to question its continued routine use in a variety of operating room settings. Adverse events may result from both the biological actions of nitrous oxide and the fact that to deliver an effective dose, nitrous oxide, which is a relatively weak anaesthetic agent, needs to be given in high concentrations that restrict oxygen delivery (for example, a common mixture is 30% oxygen with 70% nitrous oxide). As well as the risk of low blood oxygen levels, concerns have also been raised regarding the risk of compromising the immune system, impaired cognition, postoperative cardiovascular complications, bowel obstruction from distention, and possible respiratory compromise.

OBJECTIVES

To determine if nitrous oxide-based anaesthesia results in similar outcomes to nitrous oxide-free anaesthesia in adults undergoing surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014 Issue 10); MEDLINE (1966 to 17 October 2014); EMBASE (1974 to 17 October 2014); and ISI Web of Science (1974 to 17 October 2014). We also searched the reference lists of relevant articles, conference proceedings, and ongoing trials up to 17 October 2014 on specific websites (http://clinicaltrials.gov/, http://controlled-trials.com/, and http://www.centerwatch.com).

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing general anaesthesia where nitrous oxide was part of the anaesthetic technique used for the induction or maintenance of general anaesthesia (or both) with any general anaesthesia using a volatile anaesthetic or propofol-based maintenance of anaesthesia but no nitrous oxide for adults undergoing surgery. Our primary outcome was inhospital case fatality rate. Secondary outcomes were complications and length of stay.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted the outcome data. We used meta-analysis for data synthesis. Heterogeneity was examined with the Chi² test and by calculating the I² statistic. We used a fixed-effect model if the measure of inconsistency was low for all comparisons (I² statistic < 50%); otherwise we used a random-effects model for measures with high inconsistency. We undertook subgroup analyses to explore inconsistency and sensitivity analyses to evaluate whether the results were robust. We assessed the quality of evidence of the main outcomes using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

MAIN RESULTS

We included 35 trials (13,872 adult participants). Seven included studies were at low risk of bias. We identified eight studies as awaiting classification since we could not obtain the full texts, and had insufficient information to include or exclude them. We included data from 24 trials for quantitative synthesis. The results of meta-analyses showed that nitrous oxide-based techniques increased the incidence of pulmonary atelectasis (odds ratio (OR) 1.57, 95% confidence interval (CI) 1.18 to 2.10, P = 0.002), but had no effects on the inhospital case fatality rate, the incidence of pneumonia, myocardial infarction, stroke, severe nausea and vomiting, venous thromboembolism, wound infection, or the length of hospital stay. The sensitivity analyses suggested that the results of the meta-analyses were all robust except for the outcomes of pneumonia, and severe nausea and vomiting. Two trials reported length of intensive care unit (ICU) stay but the data were skewed so were not pooled. Both trials reported that nitrous oxide-based techniques had no effects on the length of ICU stay. We rated the quality of evidence for two outcomes (pulmonary atelectasis, myocardial infarction) as high, four outcomes (inhospital case fatality rate, stroke, venous thromboembolism, length of hospital stay) as moderate, and three (pneumonia, severe nausea and vomiting, wound infection rate) as low.

AUTHORS' CONCLUSIONS

Given the evidence from this Cochrane review, the avoidance of nitrous oxide may be reasonable in participants with pre-existing poor pulmonary function or at high risk of postoperative nausea and vomiting. Since there are eight studies awaiting classification, selection bias may exist in our systematic review.

Pain control in first trimester surgical abortion

BACKGROUND

First trimester abortions especially cervical dilation and suction aspiration are associated with pain, despite various methods of pain control.

OBJECTIVES

Compare different methods of pain control during first trimester surgical abortion.

SEARCH STRATEGY

We searched multiple electronic databases with the appropriate key words, as well as reference lists of articles, and contacted professionals to seek other trials.

SELECTION CRITERIA

Randomized controlled trials comparing methods of pain control in first trimester surgical abortion at less than 14 weeks gestational age using electric or manual suction aspiration. Outcomes included intra- and postoperative pain, side effects, recovery measures and satisfaction.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data. Meta-analysis results are expressed as weighted mean difference (WMD) or Peto Odds ratio with 95% confidence interval (CI).

MAIN RESULTS

We included forty studies with 5131 participants. Due to heterogeneity we divided studies into 7 groups:Local anesthesia: Data was insufficient to show a clear benefit of a paracervical block (PCB) compared to no PCB or a PCB with bacteriostatic saline. Pain scores during dilation and aspiration were improved with deep injection (WMD -1.64 95% CI -3.21 to -0.08; WMD 1.00 95% CI 1.09 to 0.91), and with adding a 4% intrauterine lidocaine infusion (WMD -2.0 95% CI -3.29 to -0.71, WMD -2.8 95% CI -3.95 to -1.65 with dilation and aspiration respectively).PCB with premedication: Ibuprofen and naproxen resulted in small reduction of intra- and post-operative pain.Analgesia: Diclofenac-sodium did not reduce pain.Conscious sedation: The addition of conscious intravenous sedation using diazepam and fentanyl to PCB decreased procedural pain.General anesthesia (GA): Conscious sedation increased intraoperative but decreased postoperative pain compared to GA (Peto OR 14.77 95% CI 4.91 to 44.38, and Peto OR 7.47 95% CI 2.2 to 25.36 for dilation and aspiration respectively, and WMD 1.00 95% CI 1.77 to 0.23 postoperatively). Inhalation anesthetics are associated with increased blood loss (p<0.001).GA with premedication: The COX 2 inhibitor etoricoxib, the non-selective COX inhibitors lornoxicam, diclofenac and ketorolac IM, and the opioid nalbuphine were improved postoperative pain.Non-pharmacological intervention: Listening to music decreased procedural pain.No major complication was observed.

AUTHORS' CONCLUSIONS

Conscious sedation, GA and some non-pharmacological interventions decreased procedural and postoperative pain, while being safe and satisfactory to patients. Data on the widely used PCB is inadequate to support its use, and it needs to be further studied to determine any benefit.

Intravenous fluid and postoperative nausea and vomiting after day-case termination of pregnancy

BACKGROUND

Deprivation of oral fluid before minor surgery has been alleged to cause postoperative nausea. We examined the effect of intraoperative fluid load on postoperative nausea and vomiting over 3 d after day-case termination of pregnancy.

METHODS

In a randomized study, 100 patients were allocated into one of two groups; receiving 1000 ml of compound sodium lactate solution during surgery or no intraoperative fluid. Propofol and alfentanil was used to induce and maintain anaesthesia with nitrous oxide (67%) and oxygen (33%). Visual analogue scores for nausea and pain, the time and frequency of emetic episodes, analgesic and antiemetic consumption were recorded for 3 d postoperatively.

RESULTS

The scores of nausea were significantly lower in the fluid group (P < 0.05) compared with the control group at 1, 2, 4 h and during 24-48 h following surgery. The incidence of emesis was lower (P < 0.01) after discharge, and the time to first oral fluid was shorter (P < 0.05) in the fluid group. There was no difference in pain score or analgesic consumption between the groups. Five patients (10%) in the control group requested antiemetic medication compared with none in the fluid group.

CONCLUSION

Intraoperative fluid administration may offer some benefit in decreasing the incidence of postoperative nausea and vomiting following day-case surgery.

Prophylactic paracetamol for analgesia after vaginal termination of pregnancy

Many patients present to day surgery clinics for vaginal termination of pregnancy, a procedure which is frequently complicated by postoperative abdominal pain. We have assessed the efficacy of prophylactic paracetamol 1000 mg given orally shortly before surgery in 834 such patients in a randomised, placebo-controlled, double-blind study. Postoperative pain was reported in 35% of patients, with no significant difference between treated and control patients. This negative finding was unexpected and is so far unexplained, given the usual efficacy of oral paracetamol in relieving this type of pain after it has occurred.

Prophylactic analgesia for daycase termination of pregnancy. A double-blind study with controlled release dihydrocodeine

The incidence and severity of pain and nausea experienced by 40 primigravid day patients who presented for vaginal termination of pregnancy were examined. Controlled-release dihydrocodeine had no effect upon the incidence or severity of these minor sequelae. The requirements for escape analgesia and antiemetic therapy were less than anticipated and possible explanations are discussed. The low incidence of significant nausea and vomiting recorded in this study confirms that vaginal termination of pregnancy may be safely performed as day cases.