Airway Management With a Stereotactic Headframe In Situ-A Mannequin Study.

BACKGROUND: Stereotactic headframe-based imaging is often needed for target localization during surgery for insertion of deep brain stimulators. A major concern during this surgery is the need for emergency airway management while an awake or sedated patient is in the stereotactic headframe. The aim of our study was to determine the ease of emergency airway management with a stereotactic headframe in situ. MATERIALS AND METHODS: We conducted an observational study using a mannequin. A Leksell stereotactic headframe was placed on a mannequin in the operating room and the frame was fixed to the operating room table. Anesthesia personnel were asked to insert a #4 laryngeal mask and then to intubate the mannequin, using both direct (DL) and video laryngoscopy (VL). In addition, participants were asked to perform the same airway techniques in the mannequin without the headframe. Data were analyzed for time taken for airway management using different devices with and without the headframe. In addition, we compared the time taken to secure the airway between different participant groups. RESULTS: Thirty anesthesia personnel (7 residents, 12 fellows, and 11 consultants) participated in the study. With the headframe in situ, 97% of participants were able to insert a laryngeal mask on their first attempt; 93% and 97% of participants were able to intubate the mannequin using DL and VL respectively on their first attempt. Without the stereotactic headframe, all participants were able to insert the laryngeal mask and intubate on the first attempt. The average time taken to insert a laryngeal mask and intubate the mannequin using DL and VL with the headframe in situ was 39.3, 58.6, and 54.8 seconds, respectively. CONCLUSIONS: Our study showed that both laryngeal mask insertion and tracheal intubation can be performed with a stereotactic headframe in situ. A laryngeal mask is the quickest airway device to insert and can be inserted while the mannequin is in the standard surgical position. Further study is needed to validate the results in patients.

Management of the airway in patients undergoing cervical spine surgery.

The perioperative management of the airway in patients with cervical spine disease requires careful consideration. In an observational prospective cohort study, we assessed the preoperative factors that may have influenced the anesthesiologists' choice for the technique of intubation and the incidence of postoperative airway complications. We recorded information from 327 patients: mean (+/-SD) age 51+/-15 year, 138 females and 189 males, for anterior surgical approach (n=195) and posterior (n=132). The technique of intubation used was awake fiberoptic bronchoscopy (FOB) in 39% (n=128), asleep FOB 32% (n=103), asleep laryngoscopy 22% (n=72), and other asleep 7% (n=24). Awake FOB was predominately chosen for intubating patients with myelopathy (45%), unstable/fractured spine (73%), and spinal stenosis (55%) but patients with radiculopathy had more asleep FOB (49%) (P<0.001). There was no association between method of intubation and postoperative airway complications. Acute postoperative airway obstruction occurred in 4 (1.2%) patients requiring reintubation. The technique of management of the airway for cervical spine surgery varied considerably among the anesthesiologists, although the choice was not associated with postoperative airway complications.

Patient satisfaction with awake craniotomy for tumor surgery: a comparison of remifentanil and fentanyl in conjunction with propofol.

In this study we compared the effectiveness of the use of remifentanil to fentanyl in conjunction with propofol in providing conscious sedation for awake craniotomy for tumor surgery and to assess patient satisfaction with both techniques. The ability to maintain appropriate levels of sedation, adequate analgesia, and hemodynamic stability was assessed in 50 patients randomized to receive either fentanyl or remifentanil. All complications were documented. Patients were interviewed at 1 h, 4 h, and 24 h after surgery to note their recall of procedure and pain and their overall satisfaction. There were no differences in sedation and pain scores or in hemodynamic and respiratory variables between the two groups. The incidence of intraoperative complications was not different (fentanyl, 14; remifentanil, 16). Respiratory complications occurred in 9 (18%) patients (fentanyl 6, remifentanil 3). The recall and satisfaction scores were not different; 93% of all patients were completely satisfied at all interview times. The use of remifentanil infusion in conjunction with propofol is a good alternative to fentanyl and propofol for conscious sedation for the awake craniotomy and these techniques are both well accepted by the patient.

Hazards of epinephrine in transsphenoidal pituitary surgery.

A 79-year-old woman with no history of myocardial ischemia presented with symptoms of pituitary apoplexy for which an urgent transsphenoidal resection of the pituitary gland was undertaken. The nasal passages were prepared with topical application of epinephrine followed by injection of what was presumed to be 1% lidocaine containing 10 microg/ml(-1) of epinephrine. After only 1.5 mL of the solution had been injected, she developed a hypertensive crisis, which was immediately treated. Postoperatively, she developed a myocardial infarction. The risks associated with the use of vasopressors are reviewed and suggestions for their safe use are presented.

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.

Day surgery craniotomy for unruptured cerebral aneurysms: a single center experience.

BACKGROUND: Ambulatory day surgery is an evolving specialty in line with demands of modern medicine, health care services, and economics, but its role in neurovascular surgery remains controversial. The purpose of this study was to describe our experience of patients undergoing elective clipping of intact cerebral aneurysms as day surgery. METHODS: This retrospective and prospective observational study was carried out as a cohort review of patients who underwent outpatient clipping of an intact intracranial aneurysm at the Toronto Western Hospital, University Health Network, between May 2009 and November 2012. Patients were categorized as success (discharged on the same day) or failure (requiring unplanned postoperative hospital admission) of day surgery. Data included the preoperative assessment of the patient, anesthetic management, postoperative care, and the incidence of perioperative complications. Outcomes were duration of hospital stay, and any problems preventing same-day discharge. RESULTS: During the study period 25 patients aged 54±9 years underwent outpatient aneurysm repair. Seventeen patients (68%) successfully completed day surgery, and 8 patients (32%) were admitted to the hospital after surgery due to perioperative complications. Duration of hospital stay in the failure group ranged from 2 to 18 days. CONCLUSIONS: Our data demonstrates that surgical clipping of unruptured cerebral aneurysms may be performed in an outpatient setting. Careful selection of day surgery candidates and postoperative assessment for complications is needed. Further research is needed to identify potential risk factors and to target patient subgroups for successful ambulatory surgery.

Postoperative visual loss following cerebral arteriovenous malformation surgery: a case report.

We report the case of a 46 year-old woman presenting with unilateral postoperative visual loss after right frontal craniotomy for resection of an arteriovenous malformation in the supine position. The intraoperative course was uneventful with maintenance of hemodynamic stability. Blood loss was 300 ml; postoperative hemoglobin was 12.4 g/dl. In the recovery room, the patient reported loss of vision in her right eye. Ophthalmologic examination revealed decreased visual acuity, color vision, and visual field. Assessment of the retina was normal, but the patient showed a relative afferent pupillary defect consistent with the clinical diagnosis of ischemic optic neuropathy. Postoperative computer tomogram showed normal perfusion of ophthalmic artery and vein, no hemorrhage or signs of cerebral ischemia or edema. The patient recovered most of her vision 3 months after surgery. Anesthesiologists should be aware that this condition may follow uncomplicated intracranial surgeries in the supine position, and should obtain prompt ophthalmologic consultation when a patient develops postoperative visual loss.

Anesthesia for cerebral revascularization for adult moyamoya syndrome associated with sickle cell disease.

We report the anesthetic management of an adult patient undergoing cerebral revascularization surgery for moyamoya syndrome complicating sickle-cell disease (SCD). We present a 25 year-old male of African ethnicity with homozygous SCD who was experiencing worsening ischemic neurologic symptoms culminating in intraventricular hemorrhage from rupture of moyamoya vessels. Despite an extracranial-intracranial superficial temporal artery-middle cerebral artery bypass that was angiographically patent postoperatively, he subsequently required an intracranial omental transplant to improve cerebral blood flow to the anterior cerebral artery territory. Prior to both cerebral revascularization procedures, the patient had continued with his regularly scheduled red blood cell exchange transfusion. The importance of normothermia, normocarbia, normotension, and normovolemia is emphasized in the neuroanesthetic management. We conclude that the safe and efficacious operative treatment of moyamoya disease, using both direct and indirect revascularization procedures, is being increasingly described, and therefore anesthesiologists are likely to encounter similar cases in the future and need to be aware of the surgical procedures and perioperative implications. The overall principles of safe anesthesia (normotension, normocarbia, good oxygenation, normothermia, normovolemia) for patients with SCD also applies to patients with moyamoya. During a craniotomy, certain deviations from these are needed (hyperventilation and mannitol diuresis for brain volume reduction, induced hypothermia or manipulations of arterial blood pressures) but they can be safely used with careful monitoring of the patient.

Anesthesia for neuroradiology.

PURPOSE OF REVIEW: The role of anesthesia outside the operating room is rapidly expanding and evolving alongside with the advances in interventional neuroradiology. Increasingly complex diagnostic and therapeutic neuroradiological procedures are being performed on sicker patients. This review provides an overview of the principles of anesthetic management and summarizes recent advances in interventional neuroradiology. RECENT FINDINGS: There are many new areas of development in interventional neuroradiology, but each also brings with it controversy. Use of newer agents for anesthesia and for anticoagulation may change the intraoperative management of patients. The role of neurophysiological monitoring during endovascular procedures is still to be validated. The optimal mode of treating cerebral aneurysms is still being debated. There has been increasing interest in and evidence of the efficacy of carotid artery stenting in the treatment of carotid artery disease. The utility of intraoperative magnetic resonance imaging in neurosurgery is expanding rapidly. SUMMARY: Providing anesthesia in the interventional neuroradiology suite continues to be a challenge to the anesthesiologist. Understanding the anesthetic constraints and complexities and keeping abreast of the current developments in neuroradiology are crucial in ensuring the maximal benefits to and safety of patients.

Hyperglycemia in patients administered dexamethasone for craniotomy.

Hyperglycemia should be avoided during neurosurgery in order to decrease the risk of neurological injury. Dexamethasone has been associated with increased blood glucose during surgery. In this prospective, nonrandomized study, we documented the blood glucose concentration changes for 12 h in 34 nondiabetic patients undergoing craniotomy and compared patients who received intraoperative dexamethasone (10 mg IV on induction and 4 mg IV 6 h later), with or without preoperative dexamethasone, with patients who did not receive dexamethasone. Blood glucose concentrations increased from the preinduction value in all groups. Patients not taking dexamethasone before surgery, but who were given it intra- and postoperatively, had the largest peak blood glucose concentrations (11.0 +/- 2.0 mmol/L, mean +/- sd; P < 0.01) compared with patients who received no dexamethasone (7.8 +/- 2.1 mmol/L) or those who had been taking dexamethasone before surgery and continued it during surgery (8.5 +/- 1.2 mmol/L). The peak blood glucose concentrations in this group occurred 9 +/- 2 h after the induction of anesthesia. We recommend that the blood glucose concentration be monitored for at least 12 h in nondiabetic patients having neurosurgery who are newly administered dexamethasone.

Craniotomy for suprasellar meningioma in a 28-week pregnant woman without fetal heart rate monitoring.

PURPOSE: To illustrate the anesthetic management of a craniotomy for suprasellar meningioma in a 28-week pregnant woman and to review the considerations for fetal monitoring during surgery. CLINICAL FEATURES: A 33-yr-old woman presented at 28 weeks of gestation with rapidly deteriorating vision in her right eye. Neuroradiological investigations revealed a large suprasellar meningioma extending into the frontal lobe. She underwent a craniotomy for excision of the tumour at 28 weeks gestation because of the risk of irreversible blindness. Anesthetic management was tailored for pregnancy and an intracranial tumour. Intraoperative blood pressure was maintained within 10% of baseline and respiratory variables were stable. No fetal heart rate monitoring was used during the surgery, as there was no plan to perform an emergency Cesarean delivery even in the event of change in fetal monitoring. The aim was to treat the mother aggressively for any untoward events. She made a good neurological recovery after the procedure and had a spontaneous vaginal delivery at 40 weeks of gestation without any neonatal complications. CONCLUSIONS: Anesthetic management of a brain tumour during pregnancy should be tailored to the individual patient according to the circumstances. It is possible to perform this type of procedure without fetal heart rate monitoring. The decision regarding fetal monitoring should be based on the consensus of the multidisciplinary care team and the mother.

Venous air embolism during awake craniotomy in a supine patient.

PURPOSE: To report a non-fatal case of intraoperative venous air embolism (VAE) during an awake craniotomy. VAE presented with unusual clinical features. CLINICAL FEATURES: VAE during an awake craniotomy has not been reported frequently. The patient we describe presented with persistent coughing followed by tachypnea, hypoxia and reduction in end-tidal CO(2) during dural opening while undergoing an awake craniotomy in the supine position. Cardiovascular variables were stable during the episode except for transient hypertension. Having ruled out airway obstruction and low cardiac output, we concluded that air embolism was the cause. The patient responded immediately to the standard treatment of air embolism and recovered without any complication. CONCLUSION: This case illustrates a VAE during an awake craniotomy and emphasizes the importance of early diagnosis in the management.

Remifentanil with morphine transitional analgesia shortens neurological recovery compared to fentanyl for supratentorial craniotomy.

PURPOSE: To compare the recovery profiles, efficacy and safety of remifentanil and morphine for transitional analgesia with fentanyl in patients undergoing elective craniotomy for supratentorial mass lesions. METHODS: Ninety-one patients were enrolled in this prospective, randomized, multicentre study. Anesthesia was induced with thiopental and remifentanil (1.0 micro g x kg(-1) bolus and a 1 micro g x kg(-1) x min(-1) infusion) or fentanyl (1 micro g x kg(-1) bolus and a 1.0 micro g x kg(-1) x min(-1) infusion). The opioid infusion continued until the level of anesthesia was deemed appropriate for intubation. Anesthesia was maintained with N(2)O/O(2), isoflurane 0.5 MAC and remifentanil 0.2 micro g x kg(-1) x min(-1) or fentanyl 0.04 micro g x kg(-1) x min(-1). At bone flap replacement, either morphine 0.08 mg x kg(-1) (remifentanil group) or saline (fentanyl group) was given. RESULTS: Systolic blood pressure was greater in those receiving fentanyl during induction (145.6 +/-17.5 mmHg vs 128.8 +/-18.3 mmHg; P = 0.006) and intubation (126.9 +/-17.1 vs 110.9 +/-16.5 mmHg; P < 0.001). Median time to tracheal extubation was similar but less variable in the remifentanil group (remifentanil = 8 min: range = 2-44 min; fentanyl = 8 min: range = 1-732 min). The fentanyl patients required a longer time to achieve the first normal neurological score (fentanyl = 38.0 min; remifentanil = 26.0 min; P = 0.035). Both the anesthesiologists and the recovery room nurses rated remifentanil better with respect to level of consciousness. Analgesics were required earlier in patients receiving remifentanil; median time 0.5 vs 1.08 hr, P < 0.001. CONCLUSIONS: Remifentanil is a suitable alternative to fentanyl in supratentorial craniotomy. Time to preoperative neurological recovery is faster and morphine provides some transitional analgesia without compromising the quality of recovery.