Topical clonidine for neuropathic pain in adults.

BACKGROUND: Clonidine is a presynaptic alpha-2-adrenergic receptor agonist that has been used for many years to treat hypertension and other conditions, including chronic pain. Adverse events associated with systemic use of the drug have limited its application. Topical use of drugs has been gaining interest since the beginning of the century, as it may limit adverse events without loss of analgesic efficacy. Topical clonidine (TC) formulations have been investigated for almost 20 years in clinical trials. This is an update of the original Cochrane Review published in Issue 8, 2015. OBJECTIVES: The objective of this review was to assess the analgesic efficacy and safety of TC compared with placebo or other drugs in adults aged 18 years or above with chronic neuropathic pain. SEARCH METHODS: For this update we searched the Cochrane Register of Studies Online (CRSO), MEDLINE (Ovid), and Embase (Ovid) databases, and reference lists of retrieved papers and trial registries. We also contacted experts in the field. The most recent search was performed on 27 October 2021. SELECTION CRITERIA: We included randomised, double-blind studies of at least two weeks' duration comparing TC versus placebo or other active treatment in adults with chronic neuropathic pain. DATA COLLECTION AND ANALYSIS: Two review authors independently screened references for eligibility, extracted data, and assessed risk of bias. Any discrepancies were resolved by discussion or by consulting a third review author if necessary. Where required, we contacted trial authors to request additional information. We presented pooled estimates for dichotomous outcomes as risk ratios (RRs) with 95% confidence intervals (CIs), and continuous outcomes as mean differences (MDs) with P values. We used Review Manager Web software to perform the meta-analyses. We used a fixed-effect model if we considered heterogeneity as not important; otherwise, we used a random-effects model.  The review primary outcomes were: participant-reported pain relief of 50% or greater; participant-reported pain relief of 30% or greater; much or very much improved on Patient Global Impression of Change scale (PGIC); and very much improved on PGIC. Secondary outcomes included withdrawals due to adverse events; participants experiencing at least one adverse event; and withdrawals due to lack of efficacy. All outcomes were measured at the longest follow-up period. We assessed the certainty of evidence using GRADE and created two summary of findings tables. MAIN RESULTS: We included four studies in the review (two new in this update), with a total of 743 participants with painful diabetic neuropathy (PDN). TC (0.1% or 0.2%) was applied in gel form to the painful area two to three times daily. The double-blind treatment phase of three studies lasted 8 weeks to 85 days and compared TC versus placebo. In the fourth study, the double-blind treatment phase lasted 12 weeks and compared TC versus topical capsaicin. We assessed the studies as at unclear or high risk of bias for most domains; all studies were at unclear risk of bias for allocation concealment and blinding of outcome assessment; one study was at high risk of bias for blinding of participants and personnel; two studies were at high risk of attrition bias; and three studies were at high risk of bias due to notable funding concerns. We judged the certainty of evidence (GRADE) to be moderate to very low, downgrading for study limitations, imprecision of results, and publication bias. TC compared to placebo There was no evidence of a difference in number of participants with participant-reported pain relief of 50% or greater during longest follow-up period (12 weeks) between groups (risk ratio (RR) 1.21, 95% confidence interval (CI) 0.78 to 1.86; 179 participants; 1 study; low certainty evidence). However, the number of participants with participant-reported pain relief of 30% or greater during longest follow-up period (8 to 12 weeks) was higher in the TC group compared with placebo (RR 1.35, 95% CI 1.03 to 1.77; 344 participants; 2 studies, very low certainty evidence). The number needed to treat for an additional beneficial outcome (NNTB) for this comparison was 8.33 (95% CI 4.3 to 50.0). Also, there was no evidence of a difference between groups for the outcomes much or very much improved on the PGIC during longest follow-up period (12 weeks) or very much improved on PGIC during the longest follow-up period (12 weeks) (RR 1.06, 95% CI 0.76 to 1.49 and RR 1.82, 95% CI 0.89 to 3.72, respectively; 179 participants; 1 study; low certainty evidence). We observed no evidence of a difference between groups in withdrawals due to adverse events and withdrawals due to lack of efficacy during the longest follow-up period (12 weeks) (RR 0.34, 95% CI 0.04 to 3.18 and RR 1.01, 95% CI 0.06 to 15.92, respectively; 179 participants; 1 study; low certainty evidence) and participants experiencing at least one adverse event during longest follow-up period (12 weeks) (RR 0.65, 95% CI 0.14 to 3.05; 344 participants; 2 studies; low certainty evidence).  TC compared to active comparator There was no evidence of a difference in the number of participants with participant-reported pain relief of 50% or greater during longest follow-up period (12 weeks) between groups (RR 1.41, 95% CI 0.99 to 2.0; 139 participants; 1 study; low certainty evidence). Other outcomes were not reported. AUTHORS' CONCLUSIONS: This is an update of a review published in 2015, for which our conclusions remain unchanged. Topical clonidine may provide some benefit to adults with painful diabetic neuropathy; however, the evidence is very uncertain. Additional trials are needed to assess TC in other neuropathic pain conditions and to determine whether it is possible to predict who or which groups of people will benefit from TC.

Perioperative restrictive versus goal-directed fluid therapy for adults undergoing major non-cardiac surgery.

BACKGROUND: Perioperative fluid management is a crucial element of perioperative care and has been studied extensively recently; however, 'the right amount' remains uncertain. One concept in perioperative fluid handling is goal-directed fluid therapy (GDFT), wherein fluid administration targets various continuously measured haemodynamic variables with the aim of optimizing oxygen delivery. Another recently raised concept is that perioperative restrictive fluid therapy (RFT) may be beneficial and at least as effective as GDFT, with lower cost and less resource utilization. OBJECTIVES: To investigate whether RFT may be more beneficial than GDFT for adults undergoing major non-cardiac surgery. SEARCH METHODS: We searched the following electronic databases on 11 October 2019: Cochrane Central Register of Controlled Trials, in the Cochrane Libary; MEDLINE; and Embase. Additionally, we performed a targeted search in Google Scholar and searched trial registries (World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov) for ongoing and unpublished trials. We scanned the reference lists and citations of included trials and any relevant systematic reviews identified. SELECTION CRITERIA: We included randomized controlled trials (RCTs) comparing perioperative RFT versus GDFT for adults (aged ≥ 18 years) undergoing major non-cardiac surgery. DATA COLLECTION AND ANALYSIS: Two review authors independently screened references for eligibility, extracted data, and assessed risk of bias. We resolved discrepancies by discussion and consulted a third review author if necessary. When necessary, we contacted trial authors to request additional information. We presented pooled estimates for dichotomous outcomes as risk ratios (RRs) with 95% confidence intervals (CIs), and for continuous outcomes as mean differences (MDs) with standard deviations (SDs). We used Review Manager 5 software to perform the meta-analyses. We used a fixed-effect model if we considered heterogeneity as not important; otherwise, we used a random-effects model. We used Poisson regression models to compare the average number of complications per person. MAIN RESULTS: From 6396 citations, we included six studies with a total of 562 participants. Five studies were performed in participants undergoing abdominal surgery (including one study in participants undergoing cytoreductive abdominal surgery with hyperthermic intraperitoneal chemotherapy (HIPEC)), and one study was performed in participants undergoing orthopaedic surgery. In all studies, surgeries were elective. In five studies, crystalloids were used for basal infusion and colloids for boluses, and in one study, colloid was used for both basal infusion and boluses. Five studies reported the ASA (American Society of Anesthesiologists) status of participants. Most participants were ASA II (60.4%), 22.7% were ASA I, and only 16.9% were ASA III. No study participants were ASA IV. For the GDFT group, oesophageal doppler monitoring was used in three studies, uncalibrated invasive arterial pressure analysis systems in two studies, and a non-invasive arterial pressure monitoring system in one study. In all studies, GDFT optimization was conducted only intraoperatively. Only one study was at low risk of bias in all domains. The other five studies were at unclear or high risk of bias in one to three domains. RFT may have no effect on the rate of major complications compared to GDFT, but the evidence is very uncertain (RR 1.61, 95% CI 0.78 to 3.34; 484 participants; 5 studies; very low-certainty evidence). RFT may increase the risk of all-cause mortality compared to GDFT, but the evidence on this is also very uncertain (RD 0.03, 95% CI 0.00 to 0.06; 544 participants; 6 studies; very low-certainty evidence). In a post-hoc analysis using a Peto odds ratio (OR) or a Poisson regression model, the odds of all-cause mortality were 4.81 times greater with the use of RFT compared to GDFT, but the evidence again is very uncertain (Peto OR 4.81, 95% CI 1.38 to 16.84; 544 participants; 6 studies; very low-certainty evidence). Nevertheless, sensitivity analysis shows that exclusion of a study in which the final volume of fluid received intraoperatively was higher in the RFT group than in the GDFT group revealed no differences in mortality. Based on analysis of secondary outcomes, such as length of hospital stay (464 participants; 5 studies; very low-certainty evidence), surgery-related complications (364 participants; 4 studies; very low-certainty evidence), non-surgery-related complications (74 participants; 1 study; very low-certainty evidence), renal failure (410 participants; 4 studies; very low-certainty evidence), and quality of surgical recovery (74 participants; 1 study; very low-certainty evidence), GDFT may have no effect on the risk of these outcomes compared to RFT, but the evidence is very uncertain. Included studies provided no data on administration of vasopressors or inotropes to correct haemodynamic instability nor on cost of treatment. AUTHORS' CONCLUSIONS: Based on very low-certainty evidence, we are uncertain whether RFT is inferior to GDFT in selected populations of adults undergoing major non-cardiac surgery. The evidence is based mainly on data from studies on abdominal surgery in a low-risk population. The evidence does not address higher-risk populations or other surgery types. Larger, higher-quality RCTs including a wider spectrum of surgery types and a wider spectrum of patient groups, including high-risk populations, are needed to determine effects of the intervention.