The anaesthetic management of neurosurgical emergencies

Opioid-Sparing Effects of Flurbiprofen Axetil as an Adjuvant to Ropivacaine in Pre-Emptive Scalp Infiltration for Post-Craniotomy Pain: Study Protocol for a Multicenter, Randomized Controlled Trial

Background

Pain after craniotomy remains a poorly controlled problem that is mainly caused by the inflammatory reaction at the incision site. Nowadays, systemic opioids use, as first-line analgesics, is often limited because of adverse effects. Flurbiprofen axetil (FA) is a non-steroidal anti-inflammatory drug merged into emulsified lipid microspheres, which represent a strong affinity to inflammatory lesions. Local administration of flurbiprofen into a surgical wound has induced enhanced analgesic efficacy and few systemic or local adverse effects after oral surgery. However, the impact of local FA, as a non-opioid pharmacologic alternative, remains elusive on postoperative pain in craniotomy. In this study, we presume that pre-emptive infiltration of scalp with FA as an adjuvant to ropivacaine can lead to less sufentanil consumption postoperatively in patient controlled intravenous analgesia (PCIA) compared with ropivacaine alone.

Methods/Design

We design a multicenter, randomized controlled study that will enroll 216 subjects who are planned to receive supratentorial craniotomy. Patients will receive pre-emptive infiltration of scalp either with 50 mg FA and 0.5% ropivacaine, or with 0.5% ropivacaine alone. Primary outcome is total consumption of sufentanil with PCIA device at 48 h postoperatively.

Discussion

This is the first study attempting to explore the analgesic and safety profile of local FA as an adjuvant to ropivacaine for incisional pain in patients undergoing craniotomy. It will provide additional insights into the opioid-sparing analgesia pathways by local administration of NSAIDs for neurosurgery.

Intravenous versus inhalational techniques for rapid emergence from anaesthesia in patients undergoing brain tumour surgery

BACKGROUND

Brain tumour surgery usually is carried out with the patient under general anaesthesia. Over past years, both intravenous and inhalational anaesthetic agents have been used, but the superiority of one agent over the other is a topic of ongoing debate. Early and rapid emergence from anaesthesia is desirable for most neurosurgical patients. With the availability of newer intravenous and inhalational anaesthetic agents, all of which have inherent advantages and disadvantages, we remain uncertain as to which technique may result in more rapid early recovery from anaesthesia.

OBJECTIVES

To assess the effects of intravenous versus inhalational techniques for rapid emergence from anaesthesia in patients undergoing brain tumour surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 6) in The Cochrane Library, MEDLINE via Ovid SP (1966 to June 2014) and Embase via Ovid SP (1980 to June 2014). We also searched specific websites, such as www.indmed.nic.in, www.cochrane-sadcct.org and www.Clinicaltrials.gov (October 2014). We reran the searches for all databases in March 2016, and when we update the review, we will deal with the two studies of interest found through this search that are awaiting classification.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared the use of intravenous anaesthetic agents such as propofol and thiopentone with inhalational anaesthetic agents such as isoflurane and sevoflurane for maintenance of general anaesthesia during brain tumour surgery. Primary outcomes were emergence from anaesthesia (assessed by time to follow verbal commands, in minutes) and adverse events during emergence, such as haemodynamic changes, agitation, desaturation, muscle weakness, nausea and vomiting, shivering and pain. Secondary outcomes were time to eye opening, recovery from anaesthesia using the Aldrete or Modified Aldrete score (i.e. time to attain score ≥ 9, in minutes), opioid consumption, brain relaxation (as assessed by the surgeon on a 4- or 5-point scale) and complications of anaesthetic techniques, such as intraoperative haemodynamic instability in terms of hypotension or hypertension (mmHg), increased or decreased heart rate (beats/min) and brain swelling.

DATA COLLECTION AND ANALYSIS

We used standardized methods in conducting the systematic review, as described by the Cochrane Handbook for Systematic Reviews of Interventions. Two review authors independently extracted details of trial methods and outcome data from reports of all trials considered eligible for inclusion. We performed all analyses on an intention-to-treat basis. We used a fixed-effect model when we found no evidence of significant heterogeneity between studies, and a random-effects model when heterogeneity was likely. For assessments of the overall quality of evidence for each outcome that included pooled data from RCTs only, we downgraded the evidence from 'high quality' by one level for serious (or by two levels for very serious) study limitations (risk of bias), indirectness of evidence, serious inconsistency, imprecision of effect or potential publication bias.

MAIN RESULTS

We included 15 RCTs with 1833 participants. We determined that none of the RCTs were of high methodological quality. For our primary outcomes, pooled results from two trials suggest that time to emergence from anaesthesia, that is, time needed to follow verbal commands, was longer with isoflurane than with propofol (mean difference (MD) -3.29 minutes, 95% confidence interval (CI) -5.41 to -1.18, low-quality evidence), and time to emergence from anaesthesia was not different with sevoflurane compared with propofol (MD 0.28 minutes slower with sevoflurane, 95% CI -0.56 to 1.12, four studies, low-quality evidence). Pooled analyses for adverse events suggest lower risk of nausea and vomiting with propofol than with sevoflurane (risk ratio (RR) 0.68, 95% CI 0.51 to 0.91, low-quality evidence) or isoflurane (RR 0.45, 95% CI 0.26 to 0.78) and greater risk of haemodynamic changes with propofol than with sevoflurane (RR 1.85, 95% CI 1.07 to 3.17), but no differences in the risk of shivering or pain. Pooled analyses for brain relaxation suggest lower risk of tense brain with propofol than with isoflurane (RR 0.88, 95% CI 0.67 to 1.17, low-quality evidence), but no difference when propofol is compared with sevoflurane.

AUTHORS' CONCLUSIONS

The finding of our review is that the intravenous technique is comparable with the inhalational technique of using sevoflurane to provide early emergence from anaesthesia. Adverse events with both techniques are also comparable. However, we derived evidence of low quality from a limited number of studies. Use of isoflurane delays emergence from anaesthesia. These results should be interpreted with caution. Randomized controlled trials based on uniform and standard methods are needed. Researchers should follow proper methods of randomization and blinding, and trials should be adequately powered.

Propofol induces dilation and inhibits constriction in guinea pig basilar arteries

The present study investigated the direct action of propofol on guinea pig basilar arterial rings and the possible underlying mechanisms. Arterial rings, with and without endothelium, were mounted in an organ bath and connected to an isometric tension recording system. The effects of propofol (0.63-20 micrograms/mL) were compared with those of Intralipid (n = 13) after equilibration and precontraction by 5-hydroxytryptamine (5-HT). In another group (n = 8), after pretreatment with either propofol (5 micrograms/mL) or Intralipid, a contraction by 35 mM KCl was obtained and compared. Another group (n = 12) were incubated in Ca(2+)-free Krebs buffer and after depolarization by 45 mM KCl, a dose-response curve to CaCl2 was obtained to compare the effect of propofol (5 micrograms/mL) and Intralipid on the influx of Ca2+. Finally, in Ca(2+)-free Krebs buffer, the effect of Intralipid or propofol on 5-HT-evoked contractions (n = 6) were assessed. Propofol caused significant dilation with or without endothelium present, inhibited KCl-induced contraction, and significantly lowered the dose-response curve for CaCl2. In Ca(2+)-free Krebs buffer, propofol significantly inhibited 5-HT-evoked contraction, which is dependent on intracellular Ca(2+)-release. In conclusion, propofol inhibited vaso-constriction and induced vasodilation by mechanisms consistent with reduced extracellular calcium influx and suppressed intracellular calcium release.