Anesthesia for craniotomy: total intravenous anesthesia with propofol and alfentanil compared to anesthesia with thiopental sodium, isoflurane, fentanyl, and nitrous oxide

Neurosurgical Anesthesia: Optimizing Outcomes with Agent Selection

Anesthesia in neurosurgery embodies a vital element in the development of neurosurgical intervention. This undisputed interest has offered surgeons and anesthesiologists an array of anesthetic selections to utilize, though with this allowance comes the equally essential requirement of implementing a maximally appropriate agent. To date, there remains a lack of consensus and official guidance on optimizing anesthetic choice based on operating priorities including hemodynamic parameters (e.g., CPP, ICP, MAP) in addition to the route of procedure and pathology. In this review, the authors detail the development of neuroanesthesia, summarize the advantages and drawbacks of various anesthetic classes and agents, while lastly cohesively organizing the current literature of randomized trials on neuroanesthesia across various procedures.

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.

The effect of isoflurane on survival and myocardial infarction: a meta-analysis of randomized controlled studies

OBJECTIVE

The aim of this meta-analysis was to investigate the cardioprotective properties of isoflurane versus any comparator in terms of the rate of myocardial infarction and all-cause mortality.

DESIGN

Pertinent studies were searched independently in Biomed, Central, PubMed, Embase, and the Cochrane Central Register of clinical trials. The primary endpoint was mortality at the longest follow-up available.

SETTING

A hospital.

PARTICIPANTS

Randomized controlled trials.

INTERVENTION

A meta-analysis of 37 trials.

MEASUREMENTS AND MAIN RESULTS

The 37 included trials randomized 3,539 patients in cardiac (16 studies) and in noncardiac surgery (21 studies) with noninhalation comparators in 55% of trials. The overall analysis showed no difference in mortality between the isoflurane and control groups (16/1,602 [1.0%] v 23/1,937 [1.2%], odds ratios (OR) = 0.76 [0.39-1.47], p = 0.4 with 37 studies included) and no difference in the rate of myocardial infarction (3/1,312 [0.2%] v 1/1,532 [0.07%], OR = 2.03 [0.27-15.49], p = 0.5 with 30 studies included). Mortality was reduced in the isoflurane group when only studies with a low risk of bias were included in the analyses (0/540 [0%] v 5/703 [0.7%] in the control arm, OR = 0.13 [0.02-0.76], p = 0.02) with 4 cardiac and 6 noncardiac trials included and 5 noninhalation and 5 inhalation agents as the comparator. A trend was noted when a subanalysis was performed with propofol as a comparator (1/544 [0.2%] v 6/546 [1.1%], p = 0.05, with 16 studies included).

CONCLUSIONS

Isoflurane reduced mortality in high-quality studies and showed a trend toward a reduction in mortality when it was compared with propofol. No differences in the rates of overall mortality and myocardial infarction were noted.

Superior recovery profiles of propofol-based regimen as compared to isoflurane-based regimen in patients undergoing craniotomy for primary brain tumor excision: a retrospective study

PURPOSE

Studies comparing the recovery profiles of isoflurane- and propofol-based anesthesia for major intracranial surgery have reported contradictory results. The aim of our study was to clarify the emergence status in both regimens by investigating uniformly managed neuroanesthesia cases.

METHODS

The anesthesia database at Yamagata University Hospital covering the period 2002-2005 was retrospectively investigated for adult patients who underwent craniotomy for primary brain tumor excision. General anesthesia was provided by an isoflurane- (ISO group) or propofol-based (PROP group) regimen. Times to extubation and operating room (OR) discharge, perioperative consciousness levels, and perioperative variables were compared.

RESULTS

Of the 202 surgeries performed during the study period, 77 and 82 patients were anesthetized with isoflurane and propofol, respectively. Demographic data were comparable between the two groups, although the American Society of Anesthesiology grade was worse in the PROP group. Extubation times [39.5 ± 14.6 min (ISO) vs. 29.5 ± 14.9 min (PROP); P < 0.001] and OR discharge times [67.2 ± 18.0 (ISO) vs. 53.9 ± 17.6 min (PROP); P < 0.001] were significantly shorter in the PROP, with significantly better immediate consciousness levels. The differences in levels of consciousness persisted for several hours postoperatively. PROP patients had significantly higher urine outputs and lower body temperatures during anesthesia. The incidences of shivering, nausea, vomiting, and convulsions were not significantly different between the groups. The time to discharge was similar between the groups.

CONCLUSIONS

Propofol was associated with a better recovery profile and neurological condition than isoflurane, as indicated by shorter extubation and OR discharge times and better postoperative consciousness.

Comparison of propofol-alfentanil and propofol-remifentanil anaesthesia in percutaneous nephrolithotripsy

BACKGROUND AND OBJECTIVE

Percutaneous nephrolithotripsy (PCNL) is used for the fragmentation and removal of stones from the renal pelvis and renal calyceal systems. We compared the effects of propofol-alfentanil or propofol-remifentanil anaesthesia on haemodynamics, recovery characteristics and postoperative analgesic requirements during percutaneous nephrolithotripsy.

METHODS

Thirty non-premedicated patients were randomly allocated to receive either propofol-alfentanil (Group A) or propofol-remifentanil (Group R). The loading dose of the study drug was administered over 60 s (alfentanil 10 microg kg(-1) or remifentanil 1 microg kg(-1)) followed by a continuous infusion (alfentanil 15 microg kg(-1) h(-1) or remifentanil 0.15 microg kg(-1) min(-1)). Propofol was administered until loss of consciousness and maintained with a continuous infusion of 75 microg kg(-1) min(-1) in both groups. Atracurium was given for endotracheal intubation at a dose of 0.5 mg kg(-1) and maintained with a continuous infusion of 0.4 mg kg(-1) h(-1). Mean arterial pressure heart rate, the total amount of propofol, time of recovery of spontaneous ventilation, extubation and eye opening in response to verbal stimulus and analgesic requirement were recorded.

RESULTS

In Group A, mean arterial pressure was higher at the first minute in the prone position, and during skin incision and lithotripsy, and heart rate was higher during skin incision and lithotripsy when compared with Group R (P < 0.05). The total amount of propofol did not differ between groups. Time of recovery of spontaneous ventilation, extubation and eye opening were significantly shorter in Group R than Group A (P < 0.05).

CONCLUSIONS

Both propofol-remifentanil and propofol-alfentanil anaesthesia provided stable haemodynamics during percutaneous nephrolithotripsy, whereas propofol-remifentanil allowed earlier extubation.

Comparison of propofol/remifentanil and sevoflurane/remifentanil for maintenance of anaesthesia for elective intracranial surgery

BACKGROUND

Propofol and sevoflurane are suitable agents for maintenance of anaesthesia during neurosurgical procedures. We have prospectively compared these agents in combination with the short-acting opioid, remifentanil.

METHODS

Fifty unpremedicated patients undergoing elective craniotomy received remifentanil 1 microg kg(-1) followed by an infusion commencing at 0.5 microg kg(-1) min(-1) reducing to 0.25 microg kg(-1) min(-1) after craniotomy. Anaesthesia was induced with propofol, and maintained with either a target-controlled infusion of propofol, minimum target 2 microg ml(-1) or sevoflurane, initial concentration 2%(ET). Episodes of mean arterial pressure (MAP) more than 100 mm Hg or less than 60 mm Hg for more than 1 min were defined as hypertensive or hypotensive events, respectively. A surgical assessment of operating conditions and times to spontaneous respiration, extubation, obey commands and eye opening were recorded. Drug acquisition costs were calculated.

RESULTS

Twenty-four and twenty-six patients were assigned to propofol (Group P) and sevoflurane anaesthesia (Group S), respectively. The number of hypertensive events was comparable, whilst more hypotensive events were observed in Group S than in Group P (P=0.053, chi-squared test). As rescue therapy, more labetolol [45 (33) vs 76 (58) mg, P=0.073] and ephedrine [4.80 (2.21) vs 9.78 (5.59) mg, P=0.020] were used in Group S. Between group differences in recovery times were small and clinically unimportant. The combined hourly acquisition costs of hypnotic, analgesic, and vasoactive drugs appeared to be lower in patients maintained with sevoflurane than with propofol.

CONCLUSION

Propofol/remifentanil and sevoflurane/remifentanil both provided satisfactory anaesthesia for intracranial surgery.

A comparison of three anesthetic techniques in patients undergoing craniotomy for supratentorial intracranial surgery

Several anesthetic techniques have been used successfully to provide anesthesia for resection of intracranial supratentorial mass lesions. One technique used to enhance recovery involves changing anesthesia from vapor-based to propofol-based for cranial closure. However, there are no data to support a beneficial effect of this approach in the immediate postoperative period after craniotomy. We evaluated 3 anesthetic techniques in 60 patients undergoing elective surgery for supratentorial mass lesions. Patients were randomly assigned to three anesthesia study groups: propofol infusion, isoflurane inhalation, and these two techniques combined. In the combination group, once the dura was closed, isoflurane was discontinued and propofol infusion simultaneously started. We studied intra- and postoperative hemodynamics and several recovery variables for 2 h after the end of anesthesia. Baseline and average intraoperative blood pressure and heart rate values did not differ among the groups. Heart rate and blood pressure increased similarly in all groups in response to intubation and pin placement and postoperatively. None of the recovery event times (open eyes, extubation, follow commands, oriented, Aldrete score) or psychomotor test performance differed significantly. We conclude that the sequential administration of isoflurane and propofol did not provide earlier recovery and cognition than the intraoperative use of isoflurane alone.

IMPLICATIONS

We evaluated three anesthetic techniques with and without propofol in patients undergoing elective surgery for supratentorial mass lesions by using a prospective, randomized clinical study design and found that the three anesthetics did not differ in intra- or postoperative hemodynamic stability or early postoperative recovery variables.

Awake tracheal intubation with the intubating laryngeal mask in a patient with diffuse idiopathic skeletal hyperostosis

Diffuse idiopathic skeletal hyperostosis, otherwise known as Forestier's disease or ankylosing hyperostosis, is a relatively common condition that is distinguished from ankylosing spondylitis by the relative preservation of spinal function and the characteristic 'candle flame' lipping of the vertebrae. We report a patient with this condition and a well-recorded history of impossible intubation who presented for emergency laparotomy. The patient was intubated awake using the intubating laryngeal mask and sedation and anaesthesia were provided by a target-controlled infusion of propofol.

[Effects of anesthetic agents on intracranial pressure]

Barbiturates, etomidate and propofol decrease cerebral blood flow (CBF), mediated by a decrease in cerebral metabolism, thus decreasing intracranial pressure (ICP). As the reduction in CBF is secondary to a decrease in cerebral metabolism, these agents will have little effect on CBF or ICP in patients without active cerebral metabolic activity. Ketamine is usually not administered for the anaesthetic management of patients at risk of intracranial hypertension because of the reported increases in cerebral metabolism, CBF and ICP. The increase in CBF, however, may be partly mediated by a sympathetically induced increase in blood pressure and partly by a simultaneous increase in PaCO2 in spontaneously breathing patients. More recent studies report no increase in ICP or flow when ventilation is controlled or when other agents are associated. There is renewed interest in ketamine because it blocks excitatory amino acid receptors in the brain. Synthetic opioids including fentanyl, sufentanil, and alfentanil have been reported to cause an increase in ICP in patients with various intracranial lesions. When blood pressure was supported, no clinically relevant increase in ICP or flow velocity with alfentanil or sufentanil was observed. Thus, the increase in ICP reported with these agents may be related to the compensatory autoregulation-mediated vasodilation, underscoring the importance of administering these agents carefully to avoid systemic hypotension. Halothane consistently increases CBF and should not be used in patients with increased ICP. In contrast, isoflurane does not cause increase in CBF at concentrations below 1 to 1.5 MAC, although the effects on cerebral blood volume are less clear. Desflurane and sevoflurane have similar effects. CO2 reactivity is preserved with all inhaled agents. In patients with increased ICP however, it would be preferable to avoid these agents or to administer very low doses.

[Anesthetics: total intravenous anesthesia or inhalation anesthesia in neurosurgery]

In this review article the pro's and contra's of the use of either inhalational or intravenous anaesthetics for neurosurgical procedures are discussed. The objective is to stimulate thoughts concerning controversial subjects, rather than to resolve issues. It is much less complicated to approach the practice of neuroanaesthesia with a few straight forward "rules" based on laboratory measurements (such as intravenous drugs are good because they reduce CBF and ICP, whereas inhalational agents are bad because they increase CBF and ICP). It should also be noted that whereas statements about potential detrimental or beneficial effects of different anaesthetic agents are relatively common, there is a dearth of well-designed prospective studies of sufficient power to substantiate the outcome advantages or disadvantages. The choice of an anaesthetic should include more than just a consideration of the potential intracranial effects of a drug: it should also include experience with a drug and, more important a consideration of the patient as a whole.