Propofol sedation during awake craniotomy for seizures: patient-controlled administration versus neurolept analgesia

The safety and efficacy of alfentanil combined with midazolam in fiberoptic bronchoscopy sedation: A randomized, double-blind, controlled trial

Sedation is recommended by most guidelines to be offered to all patients undergoing diagnostic flexible bronchoscopy (DFB) without contraindications, and the most commonly reported regimen is midazolam in combination with a short-acting opioid (fentanyl or alfentanil) to provide both sedative and antitussive effects. However, the optimal dose or ideal regimen of the combination therapy with midazolam and opioids has not yet been found. So this randomized, double-blinded clinical trial was designed and registered (ChiCTR2100049052) to assess the safety and efficacy of midazolam combined with different doses of alfentanil in DFB sedation. Our study showed that relative high doses of alfentanil (10–25 μg/kg) combined with a fixed low dose of midazolam can markedly reduce hemodynamic fluctuations, cough reactions, patients’ discomforts, and improve their satisfaction in a dose-dependent manner during DFB, with no significant increase in the desaturation risks.

Characteristic Alterations of Network in Patients With Intraoperative Stimulation-Induced Seizures During Awake Craniotomy

Background: The use of electrocorticography (ECoG) to avoid intraoperative stimulation-induced seizure (ISS) during awake craniotomy is controversial. Although a standard direct cortical stimulating (DCS) protocol is used to identify the eloquent cortices and subcortical structures, ISS still occurs. Epilepsy is related to alterations in brain networks. In this study, we investigated specific alterations in brain networks in patients with ISS. Methods: Twenty-seven patients with glioma were enrolled and categorized into the ISS and non-ISS groups based on their history of ISS occurrence. A standard DCS protocol was used during awake craniotomy without ECoG supervision. Graph theoretical measurement was used to analyze resting-state functional magnetic resonance imaging data to quantitatively reveal alterations in the functional networks. Results: In the sensorimotor networks, the glioma significantly decreased the functional connectivity (FC) of four edges in the ISS group, which were conversely increased in the non-ISS group after multiple corrections (p < 0.001, threshold of p-value = 0.002). Regarding the topological properties, the sensorimotor network of all participants was classified as a small-world network. Glioma significantly increased global efficiency, nodal efficiency, and the sigma value, as well as decreased the shortest path length in the ISS group compared with the non-ISS group (p < 0.05). Conclusions: The specific alterations indicating patient susceptibility to ISS during DCS increased global and nodal efficiencies and decreased the shortest path length and FC induced by gliomas. If the patient has these specific alterations, ECoG is recommended to monitor after-discharge current during DCS to avoid ISS.

[Sensations of patients and their satisfaction during awake craniotomy]

Awake craniotomy (AC) has gained fantastic popularity over the past years. This approach is no longer the destiny of only highly specialized neurosurgical centers. Technical features of AC are completely developed. However, certain aspects of patients' sensations and their satisfaction are still unclear. The review is devoted to these issues. It was shown that AC is positively evaluated by the vast majority of patients. Many patients would choose this technique for redo surgery. However, there are certain important details that can adversely affect satisfaction of patients. Thus, these features should be considered in AC.

Pediatric Awake Craniotomy for Brain Lesions

Awake craniotomy is a special method to prevent motor deficits during the resection of lesions that are located in, or close to, functional areas. Although it is more commonly performed in adult patients, reports of pediatric cases undergoing awake craniotomy are limited in the literature. In our clinic, where we frequently use awake craniotomy in adult patients, we performed this method in 2 selected pediatric cases for lesion surgery. At an early age, these 2 cases diagnosed with epilepsy presented cerebral lesions, but since the lesions enclosed functional areas, surgical resection was not regarded as a treatment option at this time. In these 2 pediatric cases, we successfully completed lesion surgery with awake craniotomy. The method and the techniques employed during surgery are presented concomitant with other reports in the literature.

Awake craniotomy to maximize glioma resection: methods and technical nuances over a 27-year period

OBJECT

Awake craniotomy is currently a useful surgical approach to help identify and preserve functional areas during cortical and subcortical tumor resections. Methodologies have evolved over time to maximize patient safety and minimize morbidity using this technique. The goal of this study is to analyze a single surgeon's experience and the evolving methodology of awake language and sensorimotor mapping for glioma surgery.

METHODS

The authors retrospectively studied patients undergoing awake brain tumor surgery between 1986 and 2014. Operations for the initial 248 patients (1986–1997) were completed at the University of Washington, and the subsequent surgeries in 611 patients (1997–2014) were completed at the University of California, San Francisco. Perioperative risk factors and complications were assessed using the latter 611 cases.

RESULTS

The median patient age was 42 years (range 13–84 years). Sixty percent of patients had Karnofsky Performance Status (KPS) scores of 90–100, and 40% had KPS scores less than 80. Fifty-five percent of patients underwent surgery for high-grade gliomas, 42% for low-grade gliomas, 1% for metastatic lesions, and 2% for other lesions (cortical dysplasia, encephalitis, necrosis, abscess, and hemangioma). The majority of patients were in American Society of Anesthesiologists (ASA) Class 1 or 2 (mild systemic disease); however, patients with severe systemic disease were not excluded from awake brain tumor surgery and represented 15% of study participants. Laryngeal mask airway was used in 8 patients (1%) and was most commonly used for large vascular tumors with more than 2 cm of mass effect. The most common sedation regimen was propofol plus remifentanil (54%); however, 42% of patients required an adjustment to the initial sedation regimen before skin incision due to patient intolerance. Mannitol was used in 54% of cases. Twelve percent of patients were active smokers at the time of surgery, which did not impact completion of the intraoperative mapping procedure. Stimulation-induced seizures occurred in 3% of patients and were rapidly terminated with ice-cold Ringer's solution. Preoperative seizure history and tumor location were associated with an increased incidence of stimulation-induced seizures. Mapping was aborted in 3 cases (0.5%) due to intraoperative seizures (2 cases) and patient emotional intolerance (1 case). The overall perioperative complication rate was 10%.

CONCLUSIONS

Based on the current best practice described here and developed from multiple regimens used over a 27-year period, it is concluded that awake brain tumor surgery can be safely performed with extremely low complication and failure rates regardless of ASA classification; body mass index; smoking status; psychiatric or emotional history; seizure frequency and duration; and tumor site, size, and pathology.

Anaesthesia for awake craniotomy: A retrospective study of 54 cases

Background and Aims:

The anaesthetic challenge of awake craniotomy is to maintain adequate sedation, analgesia, respiratory and haemodynamic stability in an awake patient who should be able to co-operate during intraoperative neurological assessment. The current literature, sharing the experience on awake craniotomy, in Indian context, is minimal. Hence, we carried out a retrospective study with the aim to review and analyse the anaesthetic management and perioperative complications in patients undergoing awake craniotomy, at our centre.

Methods:

Medical records of 54 patients who underwent awake craniotomy for intracranial lesions over a period of 10 years were reviewed, retrospectively. Data regarding anaesthetic management, intraoperative complications and post-operative course were recorded.

Results:

Propofol (81.5%) and dexmedetomidine (18.5%) were the main agents used for providing conscious sedation to facilitate awake craniotomy. Hypertension (16.7%) was the most commonly encountered complication during intraoperative period, followed by seizures (9.3%), desaturation (7.4%), tight brain (7.4%), and shivering (5.6%). The procedure had to be converted to general anaesthesia in one of patients owing to refractory brain bulge. The incidence of respiratory and haemodynamic complications were comparable in the both groups (P > 0.05). There was less incidence of intraoperative seizures in patients who received propofol (P = 0.03). In post-operative period, 20% of patients developed new motor deficit. Mean intensive care unit stay was 2.8 ± 1.9 day (1–14 days) and mean hospital stay was 7.0 ± 5.0 day (3–30 days).

Conclusions:

‘Conscious sedation’ was the technique of choice for awake craniotomy, at our institute. Fentanyl, propofol, and dexmedetomidine were the main agents used for this purpose. Patients receiving propofol had less incidence of intraoperative seizure. Appropriate selection of patients, understanding the procedure of surgery, and judicious use of sedatives or anaesthetic agents are key to the success for awake craniotomy as a procedure.

Total intravenous anesthesia will supercede inhalational anesthesia in pediatric anesthetic practice

Inhalational anesthesia has dominated the practice of pediatric anesthesia. However, as the introduction of agents such as propofol, short-acting opioids, midazolam, and dexmedetomidine a monumental change has occurred. With increasing use, the overwhelming advantages of total intravenous anesthesia (TIVA) have emerged and driven change in practice. These advantages, outlined in this review, will justify why TIVA will supercede inhalational anesthesia in future pediatric anesthetic practice.

Awake craniotomy: A qualitative review and future challenges

Neurosurgery in awake patients incorporates newer technologies that require the anesthesiologists to update their skills and evolve their methodologies. They need effective communication skills and knowledge of selecting the right anesthetic drugs to ensure adequate analgesia, akinesia, along with patient satisfaction with the anesthetic conduct throughout the procedure. The challenge of providing adequate anesthetic care to an awake patient for intracranial surgery requires more than routine vigilance about anesthetic management.

Brain areas that influence general anesthesia

This document reviews the literature on local brain manipulation of general anesthesia in animals, focusing on behavioral and electrographic effects related to hypnosis or loss of consciousness. Local inactivation or lesion of wake-active areas, such as locus coeruleus, dorsal raphe, pedunculopontine tegmental nucleus, perifornical area, tuberomammillary nucleus, ventral tegmental area and basal forebrain, enhanced general anesthesia. Anesthesia enhancement was shown as a delayed emergence (recovery of righting reflex) from anesthesia or a decrease in the minimal alveolar concentration that induced loss of righting. Local activation of various wake-active areas, including pontis oralis and centromedial thalamus, promoted behavioral or electrographic arousal during maintained anesthesia and facilitated emergence. Lesion of the sleep-active ventrolateral preoptic area resulted in increased wakefulness and decreased isoflurane sensitivity, but only for 6 days after lesion. Inactivation of any structure within limbic circuits involving the medial septum, hippocampus, nucleus accumbens, ventral pallidum, and ventral tegmental area, amygdala, entorhinal and piriform cortex delayed emergence from anesthesia, and often reduced anesthetic-induced behavioral excitation. In summary, the concept that anesthesia works on the sleep-wake system has received strong support from studies that inactivated/lesioned or activated wake-active areas, and weak support from studies that lesioned sleep-active areas. In addition to the conventional wake-sleep areas, limbic structures such as the medial septum, hippocampus and prefrontal cortex are also involved in the behavioral response to general anesthesia. We suggest that hypnosis during general anesthesia may result from disrupting the wake-active neuronal activities in multiple areas and suppressing an atropine-resistant cortical activation associated with movements.

Awake surgery between art and science. Part I: clinical and operative settings

Awake surgery requires coordinated teamwork and communication between the surgeon and the anesthesiologist, as he monitors the patient, the neuroradiologist as he interprets the images for intraoperative confirmation, and the neuropsychologist and neurophysiologist as they evaluate in real-time the patient's responses to commands and questions. To improve comparison across published studies on clinical assessment and operative settings in awake surgery, we reviewed the literature, focusing on methodological differences and aims. In complex, interdisciplinary medical care, such differences can affect the outcome and the cost-benefit ratio of the treatment. Standardization of intraoperative mapping and related controversies will be discussed in Part II.

[Anesthesia for craniotomy in the conscious patient]

Craniotomy in the conscious patient (CPC) enables the neurological changes to be assessed during the mapping in epilepsy surgery, the location of the electrodes during deep brain stimulation surgery, and tumor resection in eloquent areas of the brain. CPC is a useful technique for radical surgery in order to minimize the damage to the functional areas of the brain. The anesthesiologist must ensure, adequate patient comfort, analgesia and ensure optimal collaboration. The appropriate selection of potential candidates for CPC should be made jointly with all professionals involved in the case. Knowledge of the different phases of CPC, coordination and communication among specialists, the right management of the pharmacology, and anesthetic techniques specific to CPC, along with the ability of psycho-emotional communication with the patient, determine the success of the procedure to be performed in the culture of patient safety. The aim of this review was to describe the anesthetic management, comprehensive considerations, and intraoperative neurophysiological tests for CPC.

Anesthetic considerations for awake craniotomy for epilepsy and functional neurosurgery

The two most common neurosurgical procedures that call for an awake patient include epilepsy surgery and functional neurosurgery. Monitoring patients in the awake state allows more aggressive resection of epileptogenic foci in functionally important brain regions. Careful patient selection and preparation combined with attentive monitoring and anticipation of events are fundamental to a smooth awake procedure. Current pharmacologic agents and techniques at the neuroanesthesiologist's disposal facilitate an increasing number of procedures performed in awake patients.

Awake Craniotomy for Tumour Excision

BACKGROUND

Craniotomy and excision of tumours can produce neurological deficits if the tumour is located close to eloquent areas of the brain. One technique of overcoming this problem is to keep the patient 'awake' during surgery.

METHODS

Eight patients with intra cranial space occupying lesions (ICSOL) were operated 'awake', using a combination of skull block with sedation and analgesia. A mixture of 0.125% bupivacaine and 0.5% lignocaine was used for various nerve and field blocks. Midazolam, fentanyl and propofol in titrated doses were used to achieve conscious sedation.

RESULT

The procedure was successful in all the patients. They tolerated the procedure well and were able to follow the commands intraoperatively as desired. There were no significant complications.

CONCLUSION

Awake craniotomy with skull blocks with sedation and analgesia is a well established procedure. It requires a good rapport between surgeon, anaesthesiologist and the patient.

Electroencephalogram monitoring during intracranial surgery for moyamoya disease

We describe our experience with intraoperative electroencephalography in moyamoya surgery, a method to monitor for ischemic changes during the procedure and to minimize the risk of intraoperative and perioperative stroke. Case records and intraoperative electroencephalography recordings of all patients (n=220) treated with surgical revascularization for moyamoya (pial synangiosis) performed for 14 years (1994-2008) were reviewed. Electroencephalographic slowing occurred in 100 cases (45.5%), and was persistent in nine cases (9%). Slowing coincided with specific operative manipulations, most commonly while suturing the donor vessel to the pia, and during closure of the craniotomy. Slowing generally occurred bilaterally, independently of the side of intervention. The presence, length, and severity of slowing were not predictive of perioperative ischemic events. We present additional data on intraoperative electroencephalography with a modified montage to accommodate the craniotomy. Although not predictive of perioperative ischemic events in this series, electroencephalographic changes were correlated with specific operative interventions, and revealed global responses to unilateral manipulation. These findings suggest that prospective analyses of this technique may elucidate additional methods of predicting (and possibly preventing) perioperative ischemic events.

Anesthesia for pediatric deep brain stimulation

In patients refractory to medical therapy, deep brain stimulations (DBSs) have emerged as the treatment of movement disorders particularly Parkinson's disease. Their use has also been extended in pediatric and adult patients to treat epileptogenic foci. We here performed a retrospective chart review of anesthesia records from 28 pediatric cases of patients who underwent DBS implantation for dystonia using combinations of dexmedetomidine and propofol-based anesthesia. Complications with anesthetic techniques including airway and cardiovascular difficulties were analyzed.

[Anesthesia for procedures other than neurosurgery in the adult with epilepsy]

Epilepsy is a common disease affecting between 1% and 2% of the general population. The incidence increases with age. Given the complicated etiology and pathogenesis of this disease, epileptic patients of all ages may require anesthesia. The perioperative care of these patients involves a number of special considerations, although the main issues to deal with are pharmacologic. This review gives an overview of the etiopathogenesis and pathophysiology of epilepsy and describes the general characteristics of antiepileptic drug therapy. The anesthetic implications of chronic treatment with antiepileptic agents and the interactions between these drugs and common anesthetics are discussed in more detail.

Anesthetic considerations for awake craniotomy for epilepsy

A variety of anesthetic methods, with and without airway manipulation, are available to facilitate awake intraoperative examinations and cortical stimulation, which allow more aggressive resection of epileptogenic foci in functionally important brain regions. Careful patient selection and preparation combined with attentive cooperation of the medical team are the foundation for a smooth awake procedure. With improved pharmacologic agents and variety of techniques at the neuroanesthesiologist's disposal, awake craniotomy has become an elegant approach to epileptic focus resection in functional cortex.

Prise en charge anesthésique des craniotomies en état vigile

This review article presents a detailed analysis of patients' management for awake craniotomy, at the light of the available data in the literature and the authors' experience. Indications of this type of surgery are discussed as well as anaesthetic management itself, from preoperative assessment of the patient to peroperative concerns. Anaesthetic strategy, choice of anaesthetic agents, anaesthetic technique, and management of the airway and possible complications are discussed. The authors emphasize the tricky aspect of the procedure, the necessity of rigorous patient selection and good preparation. They emphasize the need for controlled studies to validate the proposed techniques.

The laryngeal mask airway for awake craniotomy in the pediatric patient: report of three cases

The anesthetic management of three pediatric patients who underwent awake craniotomy with a combined, continuous intravenous infusion of propofol and alfentanil is described. The Laryngeal Mask Airway was effective in airway management during resection of epileptic foci with intraoperative cortical mapping and neuropsychological (speech) evaluation.

Postoperative nausea and vomiting after craniotomy for tumor surgery: a comparison between awake craniotomy and general anesthesia

STUDY OBJECTIVE

To assess the frequency of postoperative nausea and vomiting (PONV) in patients following an awake craniotomy compared to general anesthesia for tumor surgery.

DESIGN

Prospective observational and chart review of all patients having a craniotomy for tumor during one year.

SETTING

Postanesthesia care unit (PACU) and intensive care unit (ICU) of a university hospital.

PATIENTS

187 patients were reviewed. 107 patients who had a craniotomy for supratentorial tumor that was less than six hours in duration were analyzed and compared (50 awake craniotomy vs. 57 general anesthesia).

INTERVENTIONS

Medical records were reviewed for events after the first four hours until discharge. The occurrence and the time of any nausea, vomiting; the administration of antiemetics and analgesic drugs; and complications were documented.

MEASUREMENTS

Frequency of nausea, vomiting, administration of antiemetics and analgesia, and outcome between the two groups were compared using Chi-square and Student's t-test.

MAIN RESULTS

The frequency of nausea (4% vs. 23%; p = 0.012) and vomiting (0% vs. 11%; p = 0.052) were less in patients having an awake craniotomy compared to general anesthesia, but only during the first four hours. The administration of postoperative analgesia was not different between the two groups and did not influence the frequency of PONV.

CONCLUSION

The frequency of PONV during the initial recovery phase was less in patients having an awake craniotomy for tumor surgery than in patients having a similar procedure with general anesthesia.

Usefulness of monitoring brain tissue oxygen pressure during awake craniotomy for tumor resection: a case report

Awake craniotomy is indicated for surgical resection of tumors located near eloquent areas of the brain. The anesthetic technique is based on a combination of local anesthesia, sedation, and analgesia. Usually only clinical parameters are assessed and no other cerebral oxygenation monitoring techniques are applied. The authors report the use of brain tissue oxygen pressure monitoring during awake craniotomy. A 48-year-old right-handed man with a left temporoparietal mass was scheduled for awake craniotomy, cortical stimulation, and selective tumor removal. Monitoring included electrocardiography, pulse oximetry, end-tidal CO2, bladder temperature, invasive and noninvasive arterial pressure, and brain tissue oxygen pressure (PtiO2). The anesthetic technique consisted of continuous perfusions of 0.02 to 0.05 microg/kg/min remifentanil, propofol (target concentration, 0.5 to 1.2 microg/mL), and 25 to 50 microg/kg/min esmolol, and local anesthetic blockade of the head pin insertion sites and surgical incision area (a mixture of 0.2% ropivacaine, 1% lidocaine, and epinephrine, 1:200 000). Intraoperative cortical stimulation was performed to guide the resection according to the patient's verbal response. A change in PtiO2 was observed, gradually falling from 28 mm Hg at the beginning of the intervention down to 3 mm Hg. At this stage, surgical resection was concluded. On arrival at the intensive care unit, mixed dysphasia and slight weakness of the right arm were noted. Three weeks after surgery, the patient's speech is improving and the motor deficit has disappeared. This case suggests a possible role of PtiO2 in awake craniotomy as an aid in detecting intraoperative adverse events, but further experience with PtiO2 in this setting is needed.

[Anesthetic particularities of stereotaxic neurosurgery]

Functional neurosurgery procedures are long and specific. Cooperation of the patient may be necessary during surgery. The interference of anaesthetic agents with electrophysiological monitoring should be as little as possible. Local anaesthesia combined with intravenous sedation is often used, but general anaesthesia is more comfortable and secure. Since awakening during the procedure is generally planed, it has to be quick, reliable and of excellent quality. These requirements are fulfilled by the association of propofol by target-controlled infusion (TCI) and a continuous infusion of remifentanil.

Monitored anesthesia care using remifentanil and propofol for awake craniotomy

Adequate analgesia and sedation with adequate respiratory and hemodynamic control are needed during brain surgery in awake patients. In this study, a protocol using clonidine premedication, intraoperative propofol, remifentanil, and labetalol was evaluated prospectively in 25 patients (aged 50 +/- 16). In all but one patient, no significant problems regarding cooperation, brain swelling, or loss of control were noticed, and it was not necessary to prematurely discontinue any of the procedures. One patient, who was uncooperative and hypertensive, became apneic with increasing sedation, and needed a laryngeal mask airway inserted. Patients were hemodynamically stable; elevated systolic blood pressure (>or= 150 mm Hg) was measured infrequently, and there were no events of significant hypotension, tachycardia, or bradycardia. Events of hypoxemia (SAO2 <or= 95%), severe hypoxemia (SaO2 <or= 90%), or hypoventilation (respiratory rate <or=8 minute), were frequent in the first ten patients, but the incidence decreased significantly in subsequent patients (P < .001). Three patients developed a focal neurologic deficit, and two patients experienced intraoperative seizures. Nausea and vomiting were not recorded in any of the patients. Although these findings attest to the safety of awake craniotomy, they demonstrate the difficulty of achieving adequate sedation without compromising ventilation and oxygenation. The learning curve of using a new protocol and a new potent anesthetic drug is emphasized.

[Epileptogenic drugs in anesthesia]

Most anaesthetics and analgesics have both pro- and anticonvulsant activity. The data in the literature should be analysed with respect to the patient population, the recording of epileptic activity and the method of EEG analysis. Among inhaled anaesthetics, isoflurane has strong anticonvulsant properties. In some circumstances, sevoflurane may induce an epileptic activity. With the exception of ketamine and etomidate, all intravenous hypnotics may be used for anesthesia of the epileptic patient. Midazolam is a potent anticonvulsant. Among narcotics, fentanyl and alfentanil may induce clinical or electroencephalographic seizures. Considering the large number of patients treated with these agents without any neurological adverse effect, the clinical relevance of these data is unclear. Neuromuscular blocking agents do not possess pro- or anticonvulsant properties.

[Anesthesia for epilepsy surgery]

Epilepsy is rather common, affecting 0.5 to 2% of the population. Numerous patients, particularly those resistant to the antiepileptic therapy, can be surgically treated after a thorough evaluation. Surgery for epilepsy can be carried out either under general or local anaesthesia with sedation. This second approach is reserved for the extirpation of foci localised in motor, sensory or language areas. During the preoperative anaesthetic evaluation, two specific points have to be taken into account: the psychological aspect and the antiepileptic medication. During the procedure, an electrocorticography with or without stimulation may be indicated, particularly when a perioperative stimulation is scheduled. Low doses of volatile agents are chosen, and no curare and large doses of benzodiazepines and barbiturates. Awakening takes place on the operation table for a rapid and reliable neurological evaluation. During procedures performed under local anaesthesia, the anaesthetist must be ready at any time to intubate the patient in order to secure the airway.

Use of the laryngeal mask airway during awake craniotomy for tumor resection

There is an increasing trend toward performing craniotomy for primary brain tumor excision with local anesthesia. We report the use of the laryngeal mask airway as a part of an anesthetic technique designed for patients requiring awake cortical mapping during brain tumor excision.

The effect of propofol on intraoperative electrocorticography and cortical stimulation during awake craniotomies in children

Propofol has been proposed as a sedative agent during awake craniotomies. However, there are reports of propofol suppressing spontaneous epileptiform electrocorticography (ECoG) activity during seizure surgery, while others describe propofol-induced epileptiform activity. The purpose of this study was to determine if propofol interferes with ECoG and direct cortical stimulation during awake craniotomies in children. Children scheduled for awake craniotomies for resection of epileptic foci or tumours were studied. An intravenous bolus of 1-2 mg.kg-1 followed by infusion of 100-200 microgram.kg-1.min-1 of propofol was administered to induce unconsciousness. Fentanyl (0.5 microgram.kg-1) was administered incrementally to provide analgesia. After the cortex was exposed, the propofol infusion was stopped and the patient permitted to awaken. Cortical electrodes were applied. ECoG was recorded continuously on a Grass polygraph. Motor, sensory, language, and memory testing were done throughout the procedure. The cortex was stimulated with a hand-held electrode using sequential increases in voltage to map the relevant speech and motor areas. We studied 12 children (aged 11-15 years) with intractable seizures. The raw ECoG did not reveal any prolonged beta-waves associated with propofol effect. Electroencephalogram spikes due to spontaneous activity or cortical stimulation were easily detected. Cognitive, memory and speech testing was also successful. We conclude that propofol did not interfere with intraoperative ECoG during awake craniotomies. Using this technique, we were able to fully assess motor, sensory, cognitive, speech and memory function and simultaneously avoid routine airway manipulation.

Patient-controlled versus anesthesiologist-controlled conscious sedation with propofol for dental treatment in anxious patients

In a randomized, cross-over study, we prospectively compared the efficacy and quality of two methods to achieve conscious sedation with propofol in 11 unpremedicated, anxious dental patients. Each patient underwent two dental procedures, one that was conducted under target-controlled infusion (TCI) by the anesthesiologist (ACS), and the other that used patient-controlled sedation (PCS). The initial target concentration in the ACS mode was 2.5 microg/mL, which was manipulated in both directions until the desired clinical end point was achieved. In the PCS mode, a 4-mg bolus of propofol (10 mg/mL) was delivered at each activation of the machine, infused over 7 s without a lockout interval. The anxious dental patients could induce and maintain conscious sedation with the PCS settings. The mean (range) venous blood propofol concentrations were not significantly different with either mode: ACS 1.8 (0.8-2.7) microg/mL and PCS 1.2 (0.2-2.5) microg/mL. The level of patient satisfaction, quality of sedation, and treatability were not different for either mode of sedation. The intensity of amnesia for intraoperative events was related to the blood concentrations achieved. In the ACS mode, one patient became unresponsive (sedation level 4) immediately after the start of sedation. No adverse cardiorespiratory effects resulted from either mode of propofol sedation. Five patients expressed a strong preference for PCS, and three would prefer ACS in the future. The results of the present study suggest that with these PCS settings, a satisfactory level of conscious sedation and a high level of patient satisfaction was achieved.

IMPLICATIONS

In a randomized, cross-over study, the blood propofol concentrations necessary to achieve conscious sedation in anxious dental patients using a target-controlled infusion conducted by the anesthesiologist versus patient-controlled sedation were not different. With the patient-controlled sedation settings, a satisfactory level of conscious sedation and a high level of patient satisfaction were achieved.