Recent Preoperative Concussion and Postoperative Complications: A Retrospective Matched-cohort Study.

BACKGROUND: Physiological alterations during the perianesthetic period may contribute to secondary neurocognitive injury after a concussion. METHODS: Patients exposed to concussion and who received an anesthetic within 90 days were matched to unexposed patients without concussion. Intraoperative and postoperative events were compared. Subgroup analyses assessed relationships among patients with a concussion in the prior 30, 31 to 60, and 61 to 90 days and their respective unexposed matches. To facilitate identification of potential targets for further investigation, statistical comparisons are reported before, as well as after, correction for multiple comparisons. RESULTS: Sixty concussion patients were matched to 176 unexposed patients. Before correction, 28.3% postconcussion versus 14.8% unexposed patients reported postanesthesia care unit pain score≥7 (P=0.02); 16.7% concussion versus 6.5% unexposed patients reported headache within 90 days of anesthesia (P=0.02) and 23.5% of patients who received surgery and anesthesia within 30 days of concussion experienced headache within 90 days of anesthesia compared with 7.1% in the unexposed group (P=0.01). Patients who experienced concussion and had anesthesia between 31 and 60 days after injury had a postanesthesia care unit Richmond Agitation and Sedation Scale score of -1.61±1.29 versus a score of -0.2±0.45 in unexposed patients (P=0.002). After adjusting the P-value threshold for multiple comparisons, the P-value for significance was instead 0.0016 for the overall cohort. Our study revealed no significant associations with application of adjusted significance thresholds. CONCLUSIONS: There were no differences in intraoperative and postoperative outcomes in patients with recent concussion compared with unexposed patients. Before correction for multiple comparisons, several potential targets for further investigation are identified. Well-powered studies are warranted.

Safety and Efficacy of Retrograde Pyeloperfusion for Ureteral Protection during Renal Tumor Cryoablation.

PURPOSE: To determine safety and efficacy of retrograde pyeloperfusion for ureteral protection during cryoablation of adjacent renal tumors. MATERIALS AND METHODS: Retrospective review of 155 patients treated with renal cryoablation, including adjunctive retrograde pyeloperfusion, from 2005 to 2019 was performed. Ice contacted the ureter in 67 of the 155 patients who represented the study cohort. Median patient age was 68 years old (interquartile range [61, 74]), 52 patients (78%) were male, and 37 tumors (55%) were clear cell histology. Mean tumor size was 3.4 ± 1.3 cm, and 42 tumors (63%) were located at the lower pole. Treatment-related complication and oncologic outcomes were recorded based on a review of post-procedural images and chart review. RESULTS: Technical success of cryoablation was attained in 67 cases (100%), and technical success of pyeloperfusion was attained in 66 cases (99%). A total of 13 patients (19.4%) experienced SIR major C or D complications related to the procedure, including hemorrhage (n = 4), urine leak (n = 3), transient urinary obstruction (n = 2), pulmonary embolism (n = 1), hypertensive urgency (n = 1), acute respiratory failure (n = 1), and ureteropelvic junction (UPJ) stricture (n = 1). No complications were attributable to pyeloperfusion. Three of 45 patients with biopsy-proven renal cell carcinoma experienced local recurrence resulting in local recurrence-free survival of 92% (95% confidence interval, 81.5%-100%) 3 years after ablation. CONCLUSIONS: Retrograde pyeloperfusion of the renal collecting system is a relatively safe and efficacious option for ureteral protection during renal tumor cryoablation. This adjunctive procedure should be considered for patients in whom cryoablation of a renal mass could potentially involve the ureter.

Anesthesia With and Without Nitrous Oxide and Long-term Cognitive Trajectories in Older Adults.

BACKGROUND: We evaluated the hypothesis that the rate of postoperative decline in global cognition is greater in older adults exposed to general anesthesia with nitrous oxide (N2O) compared to general anesthesia without N2O. METHODS: Longitudinal measures of cognitive function were analyzed in nondemented adults, 70-91 years of age, enrolled in the Mayo Clinic Study of Aging. Linear mixed-effects models with time-varying covariates assessed the relationship between exposure to surgery with general anesthesia (surgery/GA) with or without N2O and the rate of long-term cognitive changes. Global cognition and domain-specific cognitive outcomes were defined using z scores, which measure how far an observation is, in standard deviations, from the unimpaired population mean. RESULTS: The analysis included 1819 participants: 280 exposed to GA without N2O following enrollment and before censoring during follow-up (median [interquartile range {IQR}] follow-up of 5.4 [3.9-7.9] years); 256 exposed to GA with N2O (follow-up 5.6 [4.0-7.9] years); and 1283 not exposed to surgery/GA (follow-up 4.1 [2.5-6.4] years). The slope of the global cognitive z score was significantly more negative following exposure to surgery/GA after enrollment (change in slope of -0.062 [95% confidence interval {CI}, -0.085 to -0.039] for GA without N2O, and -0.058 [95% CI, -0.080 to -0.035] for GA with N2O, both P < .001). The change in slope following exposure to surgery/GA did not differ between those exposed to anesthesia without versus with N2O (estimated difference -0.004 [95% CI, -0.035 to 0.026], P = .783). CONCLUSIONS: Exposure to surgery/GA is associated with a small, but statistically significant decline in cognitive z scores. Cognitive decline did not differ between anesthetics with and without N2O. This finding provides evidence that the use of N2O in older adults does not need to be avoided because of concerns related to decline in cognition.

Urgent Repositioning After Venous Air Embolism During Intracranial Surgery in the Seated Position: A Case Series.

BACKGROUND: Venous air embolism (VAE) is a well-described complication of neurosurgical procedures performed in the seated position. Although most often clinically insignificant, VAE may result in hemodynamic or neurological compromise resulting in urgent change to a level position. The incidence, intraoperative course, and outcome in such patients are provided in this large retrospective study. METHODS: Patients undergoing a neurosurgical procedure in the seated position at a single institution between January 2000 and October 2013 were identified. Corresponding medical records, neurosurgical operative reports, and computerized anesthetic records were searched for intraoperative VAE diagnosis. Extreme VAE was defined as a case in which urgent seated to level position change was performed for patient safety. Detailed examples of extreme VAE cases are described, including their intraoperative course, VAE management, and postoperative outcomes. RESULTS: There were 8 extreme VAE (0.47% incidence), 6 during suboccipital craniotomy (1.5%) and 2 during deep brain stimulator implantation (0.6%). VAE-associated end-expired CO2 and mean arterial pressure reductions rapidly normalized following position change. No new neurological deficits or cardiac events associated with extreme VAE were observed. In 5 of 8, surgery was completed. Central venous catheter placement and aspiration during VAE played no demonstrable role in patient outcome. CONCLUSIONS: Extreme VAE during seated intracranial neurosurgical procedures is infrequent. Extreme VAE-associated CO2 exchange and hemodynamic consequences from VAE were transient, recovering quickly back to baseline without significant neurological or cardiopulmonary morbidity.

Neuroanesthesiology Update.

We provide a synopsis of innovative research, recurring themes, and novel experimental findings pertinent to the care of neurosurgical patients and critically ill patients with neurological diseases. We cover the following broad topics: general neurosurgery, spine surgery, stroke, traumatic brain injury, monitoring, and anesthetic neurotoxicity.

Comparison of Anesthetic Management and Outcomes in Patients Having Either Transnasal or Transoral Endoscopic Odontoid Process Surgery.

BACKGROUND: Endoscopic neurosurgical procedures involving the upper cervical vertebrae are challenging due to a narrow operating field and close proximity to vital anatomical structures. Historically, transoropharyngeal (transoral) endoscopy has been the preferred approach. More recently, however, an endoscopic transnasal approach was developed as an alternative method in hopes to reduce postoperative dysphagia, a common complication following transoral neurosurgery. METHODS: Twenty-two endoscopic neurosurgical cases involving the odontoid or C1 vertebra were reviewed between January 1, 2005 and December 31, 2015 (17 and 5 through transoral and transnasal approaches, respectively). Patient demographics, anesthetic technique, intraoperative course, and postoperative outcomes such as were recorded. RESULTS: Patients who underwent transnasal odontoidectomy had a shorter length of stay and lower rates of tracheostomy compared with those having similar surgery via the transoral route. In those having transoral surgery, no patient presented to the operating room with a preexisting tracheostomy. In 16 of 17 patients within the transoral group, a tracheostomy was performed. In those having transnasal surgery, 2 of 5 patients had a preexisting tracheostomy. In the remaining 3 of 5 patients, orotracheal intubation was performed and patients were extubated after the procedure. CONCLUSIONS: The transnasal odontoid resection technique may become a more popular surgical approach without increasing rates of complications compared with those having transoral surgery. Ultimately, a larger, study is needed to further clarify these relationships.

Exposure to Surgery and Anesthesia After Concussion Due to Mild Traumatic Brain Injury.

OBJECTIVE: To describe the epidemiology of surgical and anesthetic procedures in patients recently diagnosed as having a concussion due to mild traumatic brain injury. PATIENTS AND METHODS: Study patients presented to a tertiary care center after a concussion due to mild traumatic brain injury from July 1, 2005, through June 30, 2015, and underwent a surgical procedure and anesthesia support under the direct or indirect care of a physician anesthesiologist. RESULTS: During the study period, 1038 patients met all the study inclusion criteria and subsequently received 1820 anesthetics. In this population of anesthetized patients, rates of diagnosed concussions due to sports injuries, falls, and assaults, but not motor vehicle accidents, increased during 2010-2011. Concussions were diagnosed in 965 patients (93%) within 1 week after injury. In the 552 patients who had surgery within 1 week after concussive injury, 29 (5%) had anesthesia and surgical procedures unrelated to their concussion-producing traumatic injury. The highest use of surgery occurred early after injury and most frequently required general anesthesia. Orthopedic and general surgical procedures accounted for 57% of procedures. Nine patients received 29 anesthetics before a concussion diagnosis, and all of these patients had been involved in motor vehicle accidents and received at least 1 anesthetic within 1 week of injury. CONCLUSION: Surgical and anesthesia use are common in patients after concussion. Clinicians should have increased awareness for concussion in patients who sustain a trauma and may need to take measures to avoid potentially injury-augmenting cerebral physiology in these patients.

The Role of Permissive and Induced Hypotension in Current Neuroanesthesia Practice.

BACKGROUND: Induced hypotension (IH) had been used for decades in neurosurgery to reduce the risk for intraoperative blood loss and decrease blood replacement. More recently, this method fell out of favor because of concerns for cerebral and other end-organ ischemia and worse treatment outcomes. Other contributing factors to the decline in its popularity include improvements in microsurgical technique, widespread use of endovascular procedures, and advances in blood conservation and transfusion protocols. Permissive hypotension (PH) is still being used occasionally in neurosurgery; however, its role in current anesthesia practice remains unclear. Our objective was to describe contemporary utilization of IH and PH (collectively called PH) in clinical practice among members of the Society for Neuroscience in Anesthesiology and Critical Care (SNACC). METHODS: A questionnaire was developed and distributed among SNACC members that addressed practice patterns related to the use of PH. The responses were analyzed based on the number of individuals who responded to each specific question. RESULTS: Of 72 respondents, 67.6% reported over 10 years of clinical experience, while 15.5% reported 5-10 years of post-training experience. The respondents admitted to providing anesthesia for 300 (median) neurosurgical cases per year. PH was applied most commonly during open interventions on cerebral aneurysms (50.8%) and arteriovenous malformations (46%). Seventy-three percent of respondents were not aware of any complications in their practice attributable to PH. CONCLUSION: PH is still being used in neuroanesthesia practice by some providers. Further research is justified to clarify the risks and benefits of PH in modern neuroanesthesia practice.

Perianesthetic Management of Patients With Thyroid-Stimulating Hormone-Secreting Pituitary Adenomas.

BACKGROUND: Thyroid-stimulating hormone (TSH)-secreting pituitary adenomas are a rare cause of secondary hyperthyroidism. Anesthetic management of these patients has not been formally described in the literature. MATERIALS AND METHODS: Patients who underwent resection of a TSH-secreting pituitary adenoma during 1987 to 2012 at a single institution were identified. Preoperative thyroid hormone state, anesthetic management, and outcome were recorded. Hemodynamic associations with intraoperative events were compared between those who were hyperthyroid and euthyroid at the time of surgery. RESULTS: Of 2268 patients having transsphenoidal resection of a pituitary tumor, 19 (0.84%) had resection of a TSH-secreting adenoma. At the time of surgery, 6 (32%) were hyperthyroid, 11 (58%) were euthyroid, and 2 (10%) were hypothyroid based on serum thyroxine concentration. General anesthesia was maintained with a potent inhaled anesthetic in all patients, and included nitrous oxide in 18 of 19 (95%). Seventeen (90%) had an arterial catheter placed for surgery. Only 1 patient (5%) required an intraoperative blood transfusion. There were no significant differences in heart rate or blood pressure at induction of anesthesia, upon intranasal injection of local anesthetic containing epinephrine, or upon emergence from anesthesia, between patients who were chemically hyperthyroid or euthyroid. Twelve of 19 (63%) had tumor extension beyond the sella turcica. Common complications were nausea and vomiting (42%), diabetes insipidus (32%), and temporary or permanent hypopituitarism (42%). CONCLUSIONS: Patients having resection of TSH-secreting pituitary adenomas can present in any thyroid state. An awareness of risks and potential complications in patients with TSH-secreting adenomas can help tailor perioperative care.

Neuroanesthesiology Update.

We provide a synopsis of innovative research, recurring themes, and novel experimental findings pertinent to the care of neurosurgical patients and critically ill patients with neurological diseases. The following broad topics are covered: general neurosurgery, spine surgery, stroke, traumatic brain injury, anesthetic neurotoxicity, perioperative cognitive dysfunction, and monitoring.

Hemodynamics during anesthesia for intra-arterial therapy of acute ischemic stroke.

BACKGROUND AND PURPOSE: Many studies have suggested a relationship between the type of anesthesia provided during intra-arterial therapy for acute ischemic stroke and patient outcomes. Variability in blood pressure and hypotension have previously been identified as possible reasons for worse outcomes in acute stroke. Our aim was to investigate hemodynamic parameters and neurological outcomes of patients receiving either general anesthesia or conscious sedation for intra-arterial therapy of acute stroke. METHODS: We performed a retrospective review of patients undergoing intra-arterial therapy from December 2008 to March 2015. Demographic data, baseline National Institutes of Health Stroke Scale score, preoperative physiological variables, procedural details, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate, and modified Rankin Scale scores were recorded. RESULTS: 99 patients were included in the study, with 38 receiving general anesthesia and 61 receiving conscious sedation. Patients who received general anesthesia had a lower maximum SBP (p=0.02), minimum SBP (p<0.0001), minimum DBP (p<0.0001), and minimum MAP (p<0.0001). On multivariate analysis, general anesthesia was associated with lower minimum SBP (p=0.04), DBP (p=0.02), and MAP (p=0.007). Conscious sedation was associated with more favorable neurological outcomes (p=0.02). Patients with favorable neurological outcomes had a lower maximum variability in SBP (p=0.01) and MAP (p=0.03), as well as a higher minimum DBP (p=0.03). CONCLUSIONS: Patients with acute ischemic stroke undergoing intra-arterial therapy with general anesthesia had lower minimum SBP, DBP, and MAP, greater fluctuations in blood pressure, and less favorable outcomes. More studies are needed to examine the implications of variable and reduced blood pressures and neurological outcomes.

Anesthetic management of patients undergoing resection of carcinoid metastasis to the brain.

BACKGROUND: Carcinoid tumors are derived from enterochromaffin cells and may release physiologically active compounds into the systemic circulation, leading to the development of carcinoid syndrome. Occasionally, these tumors metastasize to the brain, warranting biopsy or resection. In these surgical patients, the perioperative implications for anesthetic management are not heretofore defined in the indexed literature. METHODS: Patients who had craniotomy for biopsy or resection of intracranial carcinoid tumors were retrospectively identified at a single medical center. Patient demographics, perioperative anesthetic management, adverse events, and outcome were summarized in this case series. RESULTS: Eleven patients were identified; median age was 60 years (range = 42-78 years), and 45% were male. Immediately before surgery, 4 patients (36%) were receiving a somatostatin analog drug, and no patient had unchecked carcinoid syndrome. All patients received general anesthesia that included inhaled isoflurane and nitrous oxide, and all had invasive arterial blood pressure monitoring. One patient developed sustained hypotension after induction of anesthesia, likely related to hypovolemia and anesthetic drugs, but the possibility of carcinoid mediator release cannot be excluded. There were no other signs or symptoms of carcinoid syndrome in this or any other patient. Of all 11 patients, 10 (91%) experienced either significant disease progression (n = 2; 18%) or death (n = 8; 73%) from carcinoid disease, its sequelae, or an undetermined cause within 3 years after surgery. Of note, 3 of the deaths occurred shortly after surgery, on postoperative days 3, 7, and 8. CONCLUSIONS: In our experience, carcinoid tumor metastasis to the brain-whether because of tumor makeup or prior treatment-is unlikely to produce symptoms of new-onset carcinoid syndrome intraoperatively; however, the risk cannot be completely excluded. Postsurgical prognosis was poor, both within the hospital and after hospital discharge.

Dexmedetomidine and Mannitol for Awake Craniotomy in a Pregnant Patient.

We describe the use of dexmedetomidine for an awake neurosurgical procedure in a pregnant patient and quantify the effect of mannitol on intrauterine volume. A 27-year-old woman underwent a craniotomy, with intraprocedural motor and speech mapping, at 20 weeks of gestation. Sedation was maintained with dexmedetomidine. Mannitol at 0.25 g/kg IV was administered to control brain volume during surgery. Internal uterine volume was estimated at 1092 cm before surgery and decreased to 770 and 953 cm at 9 and 48 hours, respectively, after baseline assessment. No adverse maternal or fetal effects were noted during the intraoperative period or up to 48 hours postoperatively.

Neuroanesthesiology update.

We provide a review of both clinical and basic science literature from 2012 relevant to care of the patient with neurological disease. Our review addresses the following major areas: general neurosurgical procedures, stroke, traumatic brain injury, spine surgery, anesthetic neurotoxicity, neuroprotective strategies, electrophysiological monitoring, history, and graduate medical education. We have focused on research describing new and innovative concepts and recurring themes. This review is intended to be of interest to those working in the clinical arena and also to neuroscientists.

Neuroanesthesiology update.

With a focus on landmark investigations, common themes, and unique and innovative contributions to the literature, we provide a synopsis of the 2011 literature pertaining to general advances in neurosurgical procedures and perioperative care and anesthetic management of neurosurgical patients.

Patients' perspective on full disclosure and informed consent regarding postoperative visual loss associated with spinal surgery in the prone position.

OBJECTIVE: To determine patients' opinions regarding the person, method, and timing for disclosure of postoperative visual loss (POVL) associated with high-risk surgery. PATIENTS AND METHODS: On the basis of findings of a pilot study involving 219 patients at Mayo Clinic in Florida, we hypothesized that at least 80% of patients would prefer disclosure of POVL by the surgeon, during a face-to-face discussion, before the day of scheduled surgery. To test the hypothesis, we sent a questionnaire to 437 patients who underwent prolonged prone spinal surgical procedures at Mayo Clinic in Rochester, MN, or Mayo Clinic in Arizona from December 1, 2008, to December 31, 2009. RESULTS: Among the 184 respondents, 158 patients gave responses supporting the hypothesis vs 26 with at least 1 response not supporting it, for an observed incidence of 86%. The 2-sided 95% confidence interval is 80% to 91%. CONCLUSION: At least 80% of patients prefer full disclosure of the risk of POVL, by the surgeon, during a face-to-face discussion before the day of scheduled surgery. This finding supports development of a national patient-driven guideline for disclosing the risk of POVL before prone spinal surgery.

Neuroanesthesiology update 2010.

We provide a summary of the 2010 literature pertinent to the care of neurosurgical patients and those requiring neurocritical care. In addition, we address topics in the basic neurosciences as they relate to neuroanesthesiology. This review incorporates studies not only from both neuroanesthesiology and general anesthesiology-focused journals, but also from neurology, neurosurgery, critical care, and internal medicine journals and includes articles published after January 1, 2010, through those available on-line by November 31, 2010. We will review the broad categories of general neuroanesthesiology, with particular emphasis on cerebral physiology and pharmacology, intracranial hemorrhage, carotid artery disease, spine surgery, traumatic brain injury, neuroprotection, and neurotoxicity. When selecting articles for inclusion in this review, we gave priority to those publications that had: (1) new or novel information, (2) clinical utility, (3) a study design possessing appropriate statistical power, and/or (4) meaningful, unambiguous conclusions.

Neuroanesthesiology update.

Recent literature contains many reports of value to clinicians providing anesthetic or intensive care for neurosurgical patients or patients experiencing, or at risk for, neurological impairment. We will review many of these articles, focusing on those that address intracranial hemorrhage, intracranial procedures, carotid endarterectomy, spine surgery, and the determinants of outcome in patients with evolving or new-onset neurologic disease. Additionally, we will review articles addressing neurotoxicity, neuroprotection, and nervous system monitoring.

Airway management in patients who develop neck hematomas after carotid endarterectomy.

BACKGROUND: Progressive airway compromise from neck hematoma and edema is a feared complication of carotid endarterectomy (CEA). Despite this, the relationship of airway management technique to patient outcome has not been systematically studied in this population. We report the rate of successful airway management using various techniques in post-CEA patients. METHODS: A 10-year retrospective analysis was conducted to identify patients requiring airway management for neck exploration within 72 hours after CEA at Mayo Clinic, Rochester, MN. RESULTS: Three thousand two hundred twenty-five patients underwent CEA over a 10-year period at our institution. Forty-four (1.4%) required neck exploration for hematoma, and 42 of these required airway management immediately before neck exploration surgery. (The tracheal tube had not been removed after CEA in the remaining 2 patients.) The average interval between the completion of CEA and return to the operating room for hematoma evacuation was 6.0 +/- 6.0 hours (mean +/- SD; range, <1-32 hours). Fiberoptic airway management, performed before the induction of anesthesia, was successful in 15 of 20 patients (75%) and, in patients in whom fiberoptic tracheal intubation failed, direct laryngoscopy (DL) was successful in all 5 (3 before and 2 after the induction of general anesthesia). In the remaining 22 patients, DL was used as the initial management technique without a trial of fiberoptic intubation. DL was successful in 5 of 7 patients (71%) when performed before induction of general anesthesia and was successful in 13 of 15 patients (87%) when performed after induction of general anesthesia. Hematoma decompression facilitated DL in 3 of 4 failures of DL; tracheostomy was performed in the remaining patient. An arterial site of bleeding was subsequently identified in 36% of patients in whom no difficulty was encountered during laryngoscopy for hematoma evacuation versus 6% in whom difficulty was noted (P = 0.03). In 36 of 44 patients (82%), the tracheal tube was removed within 24 hours of surgery for neck exploration. No adverse events related to airway management were noted. There were no deaths at 2 weeks after hematoma evacuation. CONCLUSIONS: Multiple techniques resulted in successful airway control both before and after the induction of general anesthesia. Tracheal intubation was accomplished with both fiberoptic visualization and DL. In instances of poor direct visualization of the glottis, decompression of the airway by opening of the surgical incision may facilitate intubation of the trachea.

Neuroanesthesiology update.

The 2008 literature contained numerous articles of interest to physicians providing perioperative care for neurosurgical or neurologically-impaired patients. In this review, we provide a brief summary of common themes and unique or novel reports. Topics addressed are intracranial hemorrhage, traumatic brain injury, neuropharmacology, neuroprotection, spine surgery, and treatment of carotid artery atherosclerotic disease.