Recovery and neurological evaluation

Dynamic Cortical Connectivity During Propofol Sedation in Glioma Patients

BACKGROUND

The behavioral manifestations and neurophysiological responses to sedation can assist in understanding brain function after neurological damage, and can be described by cortical functional connectivity. Glioma patients may experience neurological deficits that are not clinically detectable before sedation. We hypothesized that patients with gliomas exhibit distinct cortical connectivity patterns compared to non-neurosurgical patients during sedation.

METHODS

This is a secondary analysis of a previously published prospective observational study. Patients scheduled for resection of supratentorial glioma (n=21) or a non-neurosurgical procedure (n=21) under general anesthesia were included in this study. Frontal electroencephalography (EEG) signals were recorded at different sedation levels as assessed by the Observer Assessment of Alertness/Sedation (OAA/S) score. Kernel principal component analysis and k-means clustering were used to determine possible temporal dynamics from the weighted phase lag index characteristics.

RESULTS

Ten EEG connectivity states were identified by clustering (76% consistency), each with unique properties. At OAA/S 3, the median (Q1, Q3) occurrence rates of state 6 (glioma group, 0.110 [0.083, 0.155] vs. control group, 0.070 [0.030, 0.110]; P=0.008) and state 7 (glioma group, 0.105 [0.083, 0.148] vs. control group: 0.065 [0.038, 0.090]; P=0.001), which are dominated by beta connectivity, were significantly different between the 2 groups, reflecting differential conversion of the beta band between the left and right brain regions. In addition, the temporal dynamics of the brain's functional connectivity was also reflected in the transition relationships between metastable states.

CONCLUSIONS

There were differences in EEG functional connectivity, which is dynamic, between the glioma and nonglioma groups during sedation.

Electroencephalography characteristics of patients with supratentorial glioma in different consciousness states induced by propofol

Gliomas are the most common primary intracranial malignant tumors. Some of these patients exhibit previously clinically undetected neurological deficits after sedation. The absence of neurophysiological evidence for this phenomenon limits the use of time-sensitive monitoring methods. The study aims to compare differences between glioma patients under sedation and those without intracranial lesions by comparing their EEG features. Twenty-one patients without intracranial tumors and 21 with frontal lobe supratentorial gliomas were enrolled. The EEG power spectrum of the glioma group was comparable to that of the control group for both sides of the brain (P>0.05 for all frequencies). Compared with those without intracranial lesions, the weighted phase lag index (wPLI) in the alpha and beta bands on the non-occupied side decreased. Glioma patients had weaker functional connectivity during sedation than patients without intracranial lesions, manifesting as reduced functional connectivity on the non-occupied side.

Effect of differences in extubation timing on postoperative pneumonia following meningioma resection: a retrospective cohort study

Background

This study was designed to examine extubation time and to determine its association with postoperative pneumonia (POP) after meningioma resection.

Methods

We studied extubation time for 598 patients undergoing meningioma resection from January 2016 to December 2020. Extubation time was analysed as a categorical variable and patients were grouped into extubation within 21 minutes, 21–35 minutes and ≥ 35 minutes. Our primary outcome represented the incidence of POP. The association between extubation time and POP was assessed using multivariable logistic regression mixed-effects models which adjusted for confounders previously reported. Propensity score matching (PSM) was also performed at a ratio of 1:1 to minimize potential bias.

Results

Among 598 patients (mean age 56.1 ± 10.7 years, 75.8% female), the mean extubation time was 32.4 minutes. Extubation was performed within 21 minutes (32.4%), 21–35 minutes (31.2%) and ≥ 35 minutes (36.4%), respectively, after surgery. Older patients (mean age 57.8 years) were prone to delayed extubation (≥ 35 min) in the operating room, and more inclined to perioperative fluid infusion. When extubation time was analysed as a continuous variable, there was a U-shaped relation of extubation time with POP (P for nonlinearity = 0.044). After adjustment for confounders, extubation ≥35 minutes was associated with POP (odds ratio [OR], 2.73 95% confidence interval [CI], 1.36 ~ 5.47). Additionally, the results after PSM were consistent with those before matching.

Conclusions

Delayed extubation after meningioma resection is associated with increased pneumonia incidence. Therefore, extubation should be performed as early as safely possible in the operation room.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01836-w.

The Effects of Switching from Sevoflurane to Short-Term Desflurane prior to the End of General Anesthesia on Patient Emergence and Recovery: A Randomized Controlled Trial

While sevoflurane and desflurane have been regarded as inhalation agents providing rapid induction and emergence, previous studies demonstrated the superiority of desflurane-anesthesia compared to sevoflurane-anesthesia in the postoperative recovery in obese and geriatric patients. We investigated whether a short-term switch of sevoflurane to desflurane at the end of sevoflurane-anesthesia enhances patient postoperative recovery profile in non-obese patients. We randomly divide patients undergoing elective surgery (n = 60) into two groups: sevoflurane-anesthesia group (Group-S, n = 30) and sevoflurane-desflurane group (Group-SD, n = 30). In Group-S, patients received only sevoflurane-anesthesia until the end of surgery (for >2 hours). In Group-SD, sevoflurane was stopped and switched to desflurane-anesthesia before the completion of sevoflurane-anesthesia (for approximately 30 minutes). We assessed the intergroup differences in the times to get eye-opening, extubation, and a bispectral index of 80 (BIS-80). Group-SD showed significantly shorter times to get eye-opening (438 ± 101 vs. 295 ± 45 s; mean difference, 143 s; 95% confidence interval [CI], 101–183; p < 0.001), extubation (476 ± 108 vs. 312 ± 42 s; mean difference, 164 s; 95% CI, 116–220; p < 0.001), and BIS-80 (378 ± 124 vs. 265 ± 49 minutes; mean difference, 113 s; 95% CI, 58–168 p < 0.001) compared to Group-S. There was no between-group difference in postoperative nausea, vomiting, and hypoxia incidences. Our results suggested that the short-term (approximately 30 minutes) switch of sevoflurane to desflurane at the end of sevoflurane-anesthesia can facilitate the speed of postoperative patient recovery.

Hemodynamic Response, Coughing and Incidence of Cerebrospinal Fluid Leakage on Awakening with an Endotracheal Tube or Laryngeal Mask Airway in Place after Transsphenoidal Pituitary Surgery: A Randomized Clinical Trial

We aimed to compare systemic and cerebral hemodynamics and coughing during emergence after pituitary surgery after endotracheal tube (ETT) extubation or after replacing ETT with a laryngeal mask airway (LMA). Patients were randomized to awaken with an ETT in place or after replacing it with an LMA. We recorded mean arterial pressure (MAP), heart rate, middle cerebral artery (MCA) flow velocity, regional cerebral oxygen saturation (SrO2), cardiac index, plasma norepinephrine, need for vasoactive drugs, coughing during emergence, and postoperative cerebrospinal fluid (CSF) leakage. The primary endpoint was postoperative MAP; secondary endpoints were SrO2 and coughing incidence. Forty-five patients were included. MAP was lower during emergence than at baseline in both groups. There were no significant between-group differences in blood pressure, nor in the number of patients that required antihypertensive drugs during emergence (ETT: 8 patients (34.8%) vs. LMA: 3 patients (14.3%); p = 0.116). MCA flow velocity was higher in the ETT group (e.g., mean (95% CI) at 15 min, 103.2 (96.3-110.1) vs. 89.6 (82.6-96.5) cm·s-1; p = 0.003). SrO2, cardiac index, and norepinephrine levels were similar. Coughing was more frequent in the ETT group (81% vs. 15%; p < 0.001). CSF leakage occurred in three patients (13%) in the ETT group. Placing an LMA before removing an ETT during emergence after pituitary surgery favors a safer cerebral hemodynamic profile and reduces coughing. This strategy may lower the risk for CSF leakage.

Acute consequences of a unilateral VIIIth nerve transection on vestibulo-ocular and optokinetic reflexes in Xenopus laevis tadpoles

Loss of peripheral vestibular function provokes severe impairments of gaze and posture stabilization in humans and animals. However, relatively little is known about the extent of the instantaneous deficits. This is mostly due to the fact that in humans a spontaneous loss often goes unnoticed initially and targeted lesions in animals are performed under deep anesthesia, which prevents immediate evaluation of behavioral deficits. Here, we use isolated preparations of Xenopus laevis tadpoles with functionally intact vestibulo-ocular (VOR) and optokinetic reflexes (OKR) to evaluate the acute consequences of unilateral VIIIth nerve sections. Such in vitro preparations allow lesions to be performed in the absence of anesthetics with the advantage to instantly evaluate behavioral deficits. Eye movements, evoked by horizontal sinusoidal head/table rotation in darkness and in light, became reduced by 30% immediately after the lesion and were diminished by 50% at 1.5 h postlesion. In contrast, the sinusoidal horizontal OKR, evoked by large-field visual scene motion, remained unaltered instantaneously but was reduced by more than 50% from 1.5 h postlesion onwards. The further impairment of the VOR beyond the instantaneous effect, along with the delayed decrease of OKR performance, suggests that the immediate impact of the sensory loss is superseded by secondary consequences. These potentially involve homeostatic neuronal plasticity among shared VOR-OKR neuronal elements that are triggered by the ongoing asymmetric activity. Provided that this assumption is correct, a rehabilitative reduction of the vestibular asymmetry might restrict the extent of the secondary detrimental effect evoked by the principal peripheral impairment.

Midazolam Sedation Induces Upper Limb Coordination Deficits That Are Reversed by Flumazenil in Patients with Eloquent Area Gliomas

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Background

Midazolam has been found to exacerbate or unmask limb motor dysfunction in patients with brain tumors. This study aimed to determine whether the exacerbated upper limb motor-sensory deficits are mediated through benzodiazepine sites by demonstrating reversibility by flumazenil in patients with gliomas in eloquent areas.

Methods

This was an interventional, parallel assignment, nonrandomized trial. Study subjects were admitted in the operating room. Patients with supratentorial eloquent area gliomas and volunteers of similar age without neurologic disease were sedated with midazolam, but still responsive and cooperative. Motor and sensory functions for upper extremities were evaluated by the Nine-Hole Peg Test before and after midazolam, as well as after flumazenil reversal.

Results

Thirty-two cases were included: 15 in the glioma group and 17 in the control group. The total dose of midazolam and flumazenil were comparable between the groups. In the glioma group, the times to task completion after midazolam in the contralateral hand (P = 0.001) and ipsilateral hand (P = 0.002) were 26.5 (95% CI, 11.3 to 41.7) and 13.7 (95% CI, 5.0 to 22.4) seconds slower than baseline, respectively. After flumazenil reversal, the contralateral hand (P = 0.99) and ipsilateral hand (P = 0.187) performed 1.2 (95% CI, −3.3 to 5.8) and 1.5 (95% CI, −0.5 to 3.5) seconds slower than baseline, respectively. In the control group, the dominant (P &lt; 0.001) and nondominant hand (P = 0.006) were 2.9 (95% CI, 1.4 to 4.3) and 1.7 (95% CI, 0.5 to 2.9) seconds slower than baseline, respectively. After flumazenil, the dominant hand (P = 0.99) and nondominant hand (P = 0.019) performed 0.2 (95% CI, −0.7 to 1.0) and 1.3 (95% CI, −0.2 to 2.4) seconds faster than baseline, respectively.

Conclusions

In patients with eloquent area gliomas, mild sedation with midazolam induced motor coordination deficits in upper limbs. This deficit was almost completely reversed by the benzodiazepine antagonist flumazenil, suggesting that this is a reversible abnormality linked to occupation of the receptor by midazolam.

Bi-frontal pneumocephalus is an independent risk factor for early postoperative agitation in adult patients admitted to intensive care unit after elective craniotomy for brain tumor: A prospective cohort study

Postoperative agitation frequently occurs after general anesthesia and may be associated with serious consequences. However, studies in neurosurgical patients have been inadequate. We aimed to investigate the incidence and risk factors for early postoperative agitation in patients after craniotomy, specifically focusing on the association between postoperative pneumocephalus and agitation. Adult intensive care unit admitted patients after elective craniotomy under general anesthesia were consecutively enrolled. Patients were assessed using the Sedation-Agitation Scale during the first 24 hours after operation. The patients were divided into two groups based on their maximal Sedation-Agitation Scale: the agitation (Sedation-Agitation Scale ≥ 5) and non-agitation groups (Sedation-Agitation Scale ≤ 4). Preoperative baseline data, intraoperative and intensive care unit admission data were recorded and analyzed. Each patient's computed tomography scan obtained within six hours after operation was retrospectively reviewed. Modified Rankin Scale and hospital length of stay after the surgery were also collected. Of the 400 enrolled patients, agitation occurred in 13.0% (95% confidential interval: 9.7-16.3%). Body mass index, total intravenous anesthesia, intraoperative fluid intake, intraoperative bleeding and transfusion, consciousness after operation, endotracheal intubation kept at intensive care unit admission and mechanical ventilation, hyperglycemia without a history of diabetes, self-reported pain and postoperative bi-frontal pneumocephalus were used to build a multivariable model. Bi-frontal pneumocephalus and delayed extubation after the operation were identified as independent risk factors for postoperative agitation. After adjustment for confounding, postoperative agitation was independently associated with worse neurologic outcome (odd ratio: 5.4, 95% confidential interval: 1.1-28.9, P = 0.048). Our results showed that early postoperative agitation was prevalent among post-craniotomy patients and was associated with adverse outcomes. Improvements in clinical strategies relevant to bi-frontal pneumocephalus should be considered.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02318199).

National survey on postoperative care and treatment circuits in neurosurgery

INTRODUCTION

The analysis of surgical processes should be a standard of health systems. We describe the circuit of care and postoperative treatment for neurosurgical interventions in the centres of our country.

MATERIAL AND METHODS

From June to October 2014, a survey dealing with perioperative treatments and postoperative circuits after neurosurgical procedures was sent to the chiefs of Anaesthesiology of 73 Spanish hospitals with neurosurgery and members of the Neuroscience Section of SEDAR.

RESULTS

We obtained 45 responses from 30 centres (41.09%). Sixty percent of anaesthesiologists perform preventive locoregional analgesic treatment. Pain intensity is systematically assessed by 78%. Paracetamol, non-steroidal anti-inflammatory and morphine combinations are the most commonly used. A percentage of 51.1 are aware of the incidence of postoperative nausea after craniotomy and 86.7% consider multimodal prophylaxis to be necessary. Dexamethasone is given as antiemetic (88.9%) and/or anti-oedema treatment (68.9%). A percentage of 44.4 of anaesthesiologists routinely administer anticonvulsive prophylaxis in patients with supratentorial tumours (levetiracetam, 88.9%), and 73.3% of anaesthesiologists have postoperative surveillance protocols. The anaesthesiologist (73.3%) decides the patient's destination, which is usually ICU (83.3%) or PACU (50%). Postoperative neurological monitoring varied according to the type of intervention, although strength and sensitivity were explored in between 70-80%.

CONCLUSIONS

There is great variability in the responses, probably attributable to the absence of guidelines, different structures and hospital equipment, type of surgery and qualified personnel. We need consensual protocols to standardize the treatment and the degree of monitoring needed during the postoperative period.

Postoperative surveillance in neurosurgical patients - usefulness of neurological assessment scores and bispectral index

BACKGROUND AND OBJECTIVES

We examined the additive effect of the Ramsay scale, Canadian Neurological Scale (CNS), Nursing Delirium Screening Scale (Nu-DESC), and Bispectral Index (BIS) to see whether along with the assessment of pupils and Glasgow Coma Scale (GCS) it improved early detection of postoperative neurological complications.

METHODS

We designed a prospective observational study of two elective neurosurgery groups of patients: craniotomies (CG) and non-craniotomies (NCG). We analyze the concordance and the odds ratio (OR) of altered neurological scales and BIS in the Post-Anesthesia Care Unit (PACU) for postoperative neurological complications. We compared the isolated assessment of pupils and GCS (pupils-GCS) with all the neurologic assessment scales and BIS (scales-BIS).

RESULTS

In the CG (n=70), 16 patients (22.9%) had neurological complications in PACU. The scales-BIS registered more alterations than the pupils-GCS (31.4% vs. 20%; p<0.001), were more sensitive (94% vs. 50%) and allowed a more precise estimate for neurological complications in PACU (p=0.002; OR=7.15, 95% CI=2.1-24.7 vs. p=0.002; OR=9.5, 95% CI=2.3-39.4). In the NCG (n=46), there were no neurological complications in PACU. The scales-BIS showed alterations in 18 cases (39.1%) versus 1 (2.2%) with the pupils-GCS (p<0.001). Altered CNS on PACU admission increased the risk of neurological complications in the ward (p=0.048; OR=7.28, 95% CI=1.021-52.006).

CONCLUSIONS

Applied together, the assessment of pupils, GCS, Ramsay scale, CNS, Nu-DESC and BIS improved early detection of postoperative neurological complications in PACU after elective craniotomies.

Intraventricular hemorrhage after dural fistula embolization

BACKGROUND AND OBJECTIVES

Dural arteriovenous fistulas are anomalous shunts between dural arterial and venous channels whose nidus is located between the dural leaflets. For those circumstances when invasive treatment is mandatory, endovascular techniques have grown to become the mainstay of practice, choice attributable to their reported safety and effectiveness. We describe the unique and rare case of a dural arteriovenous fistula treated by transarterial embolization and complicated by an intraventricular hemorrhage. We aim to emphasize some central aspects of the perioperative management of these patients in order to help improving the future approach of similar cases.

CASE REPORT

A 59-year-old woman with a previously diagnosed Cognard Type IV dural arteriovenous fistula presented for transarterial embolization, performed outside the operating room, under total intravenous anesthesia. The procedure underwent without complications and the intraoperative angiography revealed complete obliteration of the fistula. In the early postoperative period, the patient presented with clinical signs of raised intracranial pressure attributable to a later diagnosed intraventricular hemorrhage, which conditioned placement of a ventricular drain, admission to an intensive care unit, cerebral vasospasm and a prolonged hospital stay. Throughout the perioperative period, there were no changes in the cerebral brain oximetry. The patient was discharged without neurological sequelae.

CONCLUSION

Intraventricular hemorrhage may be a serious complication after the endovascular treatment of dural arteriovenous fistula. A close postoperative surveillance and monitoring allow an early diagnosis and treatment which increases the odds for an improved outcome.

[Intraventricular hemorrhage after dural fistula embolization]

BACKGROUND AND OBJECTIVES

Dural arteriovenous fistulas are anomalous shunts between dural arterial and venous channels whose nidus is located between the dural leaflets. For those circumstances when invasive treatment is mandatory, endovascular techniques have grown to become the mainstay of practice, choice attributable to their reported safety and effectiveness. We describe the unique and rare case of a dural arteriovenous fistula treated by transarterial embolization and complicated by an intraventricular hemorrhage. We aim to emphasize some central aspects of the perioperative management of these patients in order to help improving the future approach of similar cases.

CASE REPORT

A 59-year-old woman with a previously diagnosed Cognard Type IV dural arteriovenous fistula presented for transarterial embolization, performed outside the operating room, under total intravenous anesthesia. The procedure underwent without complications and the intraoperative angiography revealed complete obliteration of the fistula. In the early postoperative period, the patient presented with clinical signs of raised intracranial pressure attributable to a later diagnosed intraventricular hemorrhage, which conditioned placement of a ventricular drain, admission to an intensive care unit, cerebral vasospasm and a prolonged hospital stay. Throughout the perioperative period, there were no changes in the cerebral brain oximetry. The patient was discharged without neurological sequelae.

CONCLUSION

Intraventricular hemorrhage may be a serious complication after the endovascular treatment of dural arteriovenous fistula. A close postoperative surveillance and monitoring allow an early diagnosis and treatment which increases the odds for an improved outcome.

Airway Complications during and after General Anesthesia: A Comparison, Systematic Review and Meta-Analysis of Using Flexible Laryngeal Mask Airways and Endotracheal Tubes

OBJECTIVE

Flexible laryngeal mask airways (FLMAs) have been widely used in thyroidectomy as well as cleft palate, nasal, upper chest, head and neck oncoplastic surgeries. This systematic review aims to compare the incidence of airway complications that occur during and after general anesthesia when using the FLMA and endotracheal intubation (ETT). We performed a quantitative meta-analysis of the results of randomized trials.

METHODS

A comprehensive search of the PubMed, Embase and Cochrane Library databases was conducted using the key words "flexible laryngeal mask airway" and "endotracheal intubation". Only prospective randomized controlled trials (RCTs) that compared the FLMA and ETT were included. The relative risks (RRs) and the corresponding 95% confidence intervals (95% CIs) were calculated using a quality effects model in MetaXL 1.3 software to analyze the outcome data.

RESULTS

Ten RCTs were included in this meta-analysis. There were no significant differences between the FLMA and ETT groups in the incidence of difficulty in positioning the airway [RR = 1.75, 95% CI = (0.70-4.40)]; the occurrence of sore throat at one hour and 24 hours postoperative [RR = 0.90, 95% CI = (0.13-6.18) and RR = 0.95, 95% CI = (0.81-1.13), respectively]; laryngospasms [RR = 0.58, 95% CI = (0.27-1.23)]; airway displacement [RR = 2.88, 95% CI = (0.58-14.33)]; aspiration [RR = 0.76, 95% CI = (0.06-8.88)]; or laryngotracheal soiling [RR = 0.34, 95% CI = (0.10-1.06)]. Patients treated with the FLMA had a lower incidence of hoarseness [RR = 0.31, 95% CI = (0.15-0.62)]; coughing [RR = 0.28, 95% CI = (0.15-0.51)] during recovery in the postanesthesia care unit (PACU); and oxygen desaturation [RR = 0.43, 95% CI = (0.26-0.72)] than did patients treated with ETT. However, the incidence of partial upper airway obstruction in FLMA patients was significantly greater than it was for ETT patients [RR = 4.01, 95% CI = (1.44-11.18)].

CONCLUSION

This systematic review showed that the FLMA has some advantages over ETT because it results in a lower incidence of hoarseness, coughing and oxygen desaturation. There were no statistically significant differences in the difficulty of intubation or in the occurrence of laryngospasms, postoperative sore throat, airway displacement, aspiration or laryngotracheal soiling. However, there was a higher incidence of partial upper airway obstruction in the FLMA than in the ETT group. We conclude that the FLMA has some advantages over ETT, but surgeons and anesthesiologists should be cautious when applying the mouth gag, moving the head and neck, or performing oropharyngeal procedures to avoid partial upper airway obstruction and airway displacement. The FLMA should not be used on patients at high risk for aspiration.

Mild Sedation Exacerbates or Unmasks Focal Neurologic Dysfunction in Neurosurgical Patients with Supratentorial Brain Mass Lesions in a Drug-specific Manner

BACKGROUND

Sedation is commonly used in neurosurgical patients but has been reported to produce transient focal neurologic dysfunction. The authors hypothesized that in patients with frontal-parietal-temporal brain tumors, focal neurologic deficits are unmasked or exacerbated by nonspecific sedation independent of the drug used.

METHODS

This was a prospective, randomized, single-blind, self-controlled design with parallel arms. With institutional approval, patients were randomly assigned to one of the four groups: "propofol," "midazolam," "fentanyl," and "dexmedetomidine." The sedatives were titrated by ladder administration to mild sedation but fully cooperative, equivalent to Observer's Assessment of Alertness and Sedation score = 4. National Institutes of Health Stroke Scale (NIHSS) was used to evaluate the neurologic function before and after sedation. The study's primary outcome was the proportion of NIHSS-positive change in patients after sedation to Observer's Assessment of Alertness and Sedation = 4.

RESULTS

One hundred twenty-four patients were included. Ninety had no neurologic deficits at baseline. The proportion of NIHSS-positive change was midazolam 72%, propofol 52%, fentanyl 27%, and dexmedetomidine 23% (P less than 0.001 among groups). No statistical difference existed between propofol and midazolam groups (P = 0.108) or between fentanyl and dexmedetomidine groups (P = 0.542). Midazolam and propofol produced more sedative-induced focal neurologic deficits compared with fentanyl and dexmedetomidine. The neurologic function deficits were mainly limb motor weakness and ataxia. Patients with high-grade gliomas were more susceptible to the induced neurologic dysfunction regardless of the sedative.

CONCLUSIONS

Midazolam and propofol augmented or revealed neurologic dysfunction more frequently than fentanyl and dexmedetomidine at equivalent sedation levels. Patients with high-grade gliomas were more susceptible than those with low-grade gliomas.

A comparison of 1 minimum alveolar concentration desflurane and 1 minimum alveolar concentration isoflurane anesthesia in patients undergoing craniotomy for supratentorial lesions

BACKGROUND

A critical point in craniotomy is during opening of the dura and the subsequent potential for cerebral edema. Use of desflurane in neurosurgery may be beneficial because it facilitates early postoperative neurologic evaluation; however, data on the effect of desflurane on intracranial pressure in humans are limited. Isoflurane has been used extensively in neurosurgical patients.

OBJECTIVE

This study compared 1 minimum alveolar concentration (MAC) desflurane with 1 MAC isoflurane in facilitating hemodynamic stability, brain relaxation, and postoperative recovery characteristics in patients who underwent craniotomy for supratentorial lesions.

METHODS

A total of 70 patients (aged 18-65 years), with American Society of Anesthesiologists (ASA) 1 or 2 physical status, who underwent craniotomy for supratentorial lesions, were enrolled in the study. For induction of anesthesia, fentanyl (2 μg/kg IV) and propofol (2 mg/kg IV) were administered. Endotracheal intubation was performed after administration of vecuronium (0.1 mg/kg IV) for total muscle relaxation. Before insertion of the skull pins, additional fentanyl (2 μg/kg IV) was administered. Patients were randomly allocated to 1 of 2 anesthetic regimens. For maintenance of anesthesia, 35 patients received 1 MAC of desflurane (group 1) and 35 patients received 1 MAC of isoflurane (group 2) within 50% oxygen in nitrous oxide. Intraoperatively, heart rate (HR) and mean arterial pressure (MAP) were measured and recorded before induction and 1 minute after induction, after endotracheal intubation, before skull pin insertion and 1 minute after skull pin insertion, before incision and 1 minute after incision, and before extubation and 1 minute after extubation. Also, HR and MAP were recorded at 30-minute intervals. Postoperatively, extubation time, eye opening time to verbal stimuli, orientation time, and time to reach an Aldrete postanesthetic recovery score of ≥8 were recorded. In addition, opioid consumption was calculated and recorded. Brain relaxation was evaluated according to a 4-step brain relaxation scoring scale. All outcomes of the study were assessed and recorded by an anesthesiologist blinded to the volatile anesthetic gases studied.

RESULTS

No significant difference in HR was observed between the 2 groups. Intraoperative MAP values in group 1 were higher than in group 2 (P < 0.05). No significant difference was found between these groups in brain relaxation and opioid consumption. Extubation time, eye opening time to verbal stimuli, and time to reach an Aldrete score of ≥8 were found to be significantly shorter in patients in group 1 compared with patients in group 2 (P < 0.05).

CONCLUSIONS

In patients who underwent craniotomy for supratentorial lesions, patients who received 1 MAC desflurane-based anesthesia had earlier postoperative cognitive recovery and postoperative neurologic examination compared with patients who received 1 MAC isoflurane-based anesthesia. The observed benefits of early recovery from anesthesia, however, should be considered with risks such as higher MAP in patients administered 1 MAC desflurane.

[Awake craniotomy. Considerations in special situations]

Awake craniotomy was the earliest surgical procedure known, and it has become fashionable again. In the past it was used for the surgical management of intractable epilepsy, but nowadays, its indications are increasing, and it is a widely recognized technique for the resection of mass lesions involving the eloquent cortex, and for deep brain stimulation. The procedure is safe, provides excellent results, and saves money and resources. The anesthesiologist should know the principles underlying neuroanesthesia, the technique of scalp blockade, and the sedation protocols, as well as feeling comfortable with advanced airway management. The main anesthetic aim is to keep patients cooperating when required (analgesia-based anesthesia). This review attempts to summarize the most recent evidence from the clinical literature, a long as the number of patients undergoing craniotomies in the awake state are increasing, specifically in the pediatric population.

Factors influencing delayed extubation after infratentorial craniotomy for tumour resection: a prospective cohort study of 800 patients in a Chinese neurosurgical centre

OBJECTIVES

To investigate prospectively the rate of, and factors influencing, delayed extubation following infratentorial craniotomy in a Chinese neurosurgical centre.

METHODS

Patients undergoing infratentorial craniotomy for tumour resection were prospectively enrolled and stratified according to whether extubation was attempted in the operating theatre (early extubation) or not (delayed extubation). Pre- and intraoperative variables were collected and analysed. Multiple logistic regression analysis was performed, to identify factors related to delayed extubation.

RESULTS

The study included 800 patients, 398 (49.8%) of whom underwent delayed extubation. The overall rate of extubation failure was 3.6%. Independent factors related to delayed extubation were: preoperative lower cranial nerve dysfunction; hydrocephalus; tumour location; duration of surgery ≥ 6 h; estimated blood loss ≥ 1000 ml. Compared with patients in the early extubation group, those in the delayed extubation group had a higher rate of pneumonia, longer intensive care unit and postoperative hospital stays, and higher hospitalization costs.

CONCLUSIONS

Brain stem and lower cranial nerve function were the main factors affecting extubation decision-making. Further research is required, to establish criteria for delayed extubation following infratentorial craniotomy.

Laryngeal mask airways have a lower risk of airway complications compared with endotracheal intubation: a systematic review

PURPOSE

The purpose of the present study was to determine whether, in patients undergoing general anesthesia, those provided with a laryngeal mask airway (LMA) have a lower risk of airway-related complications than those undergoing endotracheal intubation.

MATERIALS AND METHODS

A systematic review of randomized prospective controlled trials was done to compare the risk of airway complications with an LMA versus an endotracheal tube (ETT) in patients receiving general anesthesia. Two independent reviewers identified 29 randomized prospective controlled trials that met the predetermined inclusion and exclusion criteria. The data for each individual outcome measure were combined to analyze the relative risk ratios (RRs). The Cochrane RevMan software was used for statistical analysis.

RESULTS

When an ETT was used to protect the airway, a statistically significant greater incidence of hoarse voice (RR 2.59, 95% confidence interval [CI] 1.55 to 4.34), a greater incidence of laryngospasm during emergence (RR 3.16, 95% CI 1.38 to 7.21), a greater incidence of coughing (RR 7.12, 95% CI 4.28 to 11.84), and a greater incidence of sore throat (RR 1.67, 95% CI 1.33 to 2.11) was found compared with when an LMA was used to protect the airway. The differences in the risk of regurgitation (RR 0.84, 95% CI 0.27 to 2.59), vomiting (RR 1.56, 95% CI 0.74 to 3.26), nausea (RR 1.59, 95% CI 0.91 to 2.78), and the success of insertion on the first attempt (RR 1.08, 95% CI 0.99 to 1.18) were not statistically significant between the 2 groups.

CONCLUSIONS

For the patients receiving general anesthesia, the use of the LMA resulted in a statistically and clinically significant lower incidence of laryngospasm during emergence, postoperative hoarse voice, and coughing than when using an ETT. The risk of aspiration could not be determined because only 1 study reported a single case of aspiration, which was in the group using the ETT.