Ehab Farag

Is Depth of Anesthesia, as Assessed by the Bispectral Index, Related to Postoperative Cognitive Dysfunction and Recovery?

We randomized 74 patients to either a lower Bispectral Index (BIS) regimen (median BIS, 38.9) or a higher BIS regimen (mean BIS, 50.7) during the surgical procedure. Preoperatively and 4–6 wk after surgery, the patients’ cognitive status was assessed with a cognitive test battery consisting of processing speed index, working memory index, and verbal memory index. Processing speed index was 113.7 ± 1.5 (mean ± se) in the lower BIS group versus 107.9 ± 1.4 in the higher BIS group (P = 0.006). No difference was observed in the other two test battery components. Somewhat deeper levels of anesthesia were therefore associated with better cognitive function 4–6 wk postoperatively, particularly with respect to the ability to process information.

Perioperative events during deep brain stimulation: The experience at Cleveland Clinic

Background Deep brain stimulation (DBS) of the basal ganglia is an evolving technique for managing intractable movement disorders such as those due to Parkinson disease. We conducted a retrospective review of the DBS procedures that have been performed at our institution to determine the frequency and types complications that occurred. Methods After Institutional Review Board approval, 258 procedures involving 250 patients were retrospectively reviewed. Univariate analysis using the χ2 test for the categorical variables and a t-test for the continuous variables was performed on patients with and without complications to determine potential risk factors. Results The most common anesthesia technique used for DBS procedures was monitored anesthesia care using a propofol infusion during the early part of the case. Airway, respiratory, neurologic, and psychologic/psychiatric complications occurred. Age was found to be an independent risk factor for complications during DBS. Conclusion This retrospective study demonstrates that age is an independent risk factor for complications during DBS procedures. Monitored anesthesia care using propofol seems to be a safe technique for DBS procedures; however, dexmedetomidine can also be used.

Motor and somatosensory evoked potentials are well maintained in patients given dexmedetomidine during spine surgery.

Background:Many commonly used anesthetic agents produce a dose-dependent amplitude reduction and latency prolongation of evoked responses, which may impair diagnosis of intraoperative spinal cord injury. Dexmedetomidine is increasingly used as an adjunct for general anesthesia. Therefore, the authors tested the hypothesis that dexmedetomidine does not have a clinically important effect on somatosensory and transcranial motor evoked responses. Methods:Thirty-seven patients were enrolled and underwent spinal surgery with instrumentation during desflurane and remifentanil anesthesia with dexmedetomidine as an anesthetic adjunct. Upper- and lower-extremity transcranial motor evoked potentials and somatosensory evoked potentials were recorded during four defined periods: baseline without dexmedetomidine; two periods with dexmedetomidine (0.3 and 0.6 ng/ml), in a randomly determined order; and a final period 1 h after drug discontinuation. The primary outcomes were amplitude and latency of P37/N20, and amplitude, area under the curve, and voltage threshold for transcranial motor evoked potential stimulation. Results:Of the total, data from 30 patients were evaluated. Use of dexmedetomidine, as an anesthetic adjunct, did not have an effect on the latency or amplitude of sensory evoked potentials greater than was prespecified as clinically relevant, and though the authors were unable to claim equivalence on the amplitude of transcranial motor evoked responses due to variability, recordings were made throughout the study in all patients. Conclusion:Use of dexmedetomidine as an anesthetic adjunct at target plasma concentrations up to 0.6 ng/ml does not change somatosensory or motor evoked potential responses during complex spine surgery by any clinically significant amount.

Neurological biomarkers in the perioperative period

The rapid detection and evaluation of patients presenting with perioperative neurological dysfunction is of great clinical relevance. Biomarkers have been defined as biological molecules that can be used as an indicator of new onset or progression of a biological process or effect of treatment. Biomarkers have become increasingly important in this setting to supplement other modalities of diagnosis such as EEG, sensory- or motor-evoked potential, transcranial Doppler, near-infrared spectroscopy, or imaging methods. A number of neuro-proteins have been identified and are currently under investigation for potential to provide insights into injury severity, outcome, and the ability to monitor cellular damage and molecular events that occur during neurological injury. S100B is a protein released by glial cells and is considered a marker of blood-brain barrier dysfunction. Clinical studies in patients undergoing cardiac and non-cardiac surgery indicate that serum levels of S100B are increased intraoperatively and after operation. The neurone-specific enolase has also been extensively investigated as a potential marker of neuronal injury in the context of cardiac and non-cardiac surgery. A third biomarker of interest is the Tau protein, which has been linked to neurodegenerative disorders. Tau appears to be more specific than the previous two biomarkers since it is only found in the central nervous system. The metalloproteinase and ubiquitin C terminal hydroxylase-L1 (UCH-L1) are the most recently researched markers; however, their usefulness is still unclear. This review presents a comprehensive overview of S100B, neuronal-specific enolase, metalloproteinases, and UCH-L1 in the perioperative period.

Cerebellar hemorrhage caused by cerebrospinal fluid leak after spine surgery

Spine surgery is associated with a wide range of surgical and anesthetic complications. Excessive cerebrospinal fluid leak can be a cause of cerebellar hemorrhage postoperatively. We report a 43-yr-old patient who had lumbar spine reexploration surgery complicated by a cerebrospinal fluid leak which led to cerebellar hemorrhage manifested by postoperative mental status changes. Early detection and proper management resulted in full recovery.

The use of dexmedetomidine in anesthesia and intensive care: a review.

The alpha-2 agonist dexmedetomidine is being increasingly used for sedation and as an adjunctive agent during general and regional anesthesia. It is used in a number of procedures and clinical settings including neuroanesthesia, vascular surgery, gastrointestinal endoscopy, fiberoptic intubation, and pediatric anesthesia. The drug is also considered a nearly ideal sedative agent in the intensive care setting. However, the drug frequently produces hypotension and bradycardia, and also decreases cerebral blood flow without concomitantly decreasing the cerebral metabolic rate for oxygen. This review discusses recent advances in the use of dexmedetomidine in anesthesia and intensive care settings, as well as discuss potential problems with its use.

Intra-Arterial Therapy for Acute Ischemic Stroke Under General Anesthesia versus Monitored Anesthesia Care

Background: Recent studies have shown that intra-arterial recanalization therapy (IAT) for acute ischemic stroke (AIS) is associated with worse clinical outcomes when performed under general anesthesia (GA) compared to local anesthesia, with or without conscious sedation. The reasons for this association have not been systematically studied. Methods: We retrospectively reviewed 190 patients who underwent IAT for anterior circulation AIS from January 2008 to December 2012 at our institution. Baseline demographics, vessels involved, acute stroke treatment including intravenous tissue type plasminogen activator (tPA) use, use of GA vs. monitored anesthesia care (MAC), location of thrombus, recanalization grade, radiologic post-procedural intracerebral hemorrhage, and 30-day outcomes were collected. Relevant clinical time points were recorded. Detailed intra-procedural hemodynamics including maximum/minimum heart rate, systolic blood pressure (BP), diastolic BP, mean BP, use of pressors and episodes of hypotension were collected. Our studys outcomes were as follows: in-hospital mortality, 30-day good outcome (mRS ≤2), successful recanalization and radiologic post-procedural intracerebral hemorrhage. Results: Ninety-one patients received GA and 99 patients received MAC. There was no significant difference in the NIHSS score between the two groups but the GA group had a higher number of ICA occlusions (31.9 vs. 18.2%, p = 0.043). The time from the start of anesthesia to incision (23.0 ± 12.5 min vs. 18.7 ± 11.3 min, p = 0.020) and the time from the start of anesthesia to recanalization (110 ± 57.2 vs. 92.3 ± 43.0, p = 0.045) was longer in the GA group. The time from incision to recanalization was not significantly different between the two groups. mRS 0-2 was achieved in 22.8% of patients in the MAC group compared to 14.9% in GA (p = 0.293). Higher mortality was seen in the GA group (25.8 vs. 13.3%, p = 0.040). Successful recanalization (TICI 2b-3) was similar between the GA and MAC (57.8 vs. 48.5%, p = 0.182) groups, but GA had a higher number of parenchymal hematomas (26.3 vs. 10.1%, p = 0.003). There was no difference in the intra-procedural hemodynamic variables between the GA and MAC groups. Anesthesia type was an independent predictor for mortality (along with age and initial NIHSS), and the only independent predictor for parenchymal hematomas, with MAC being protective for both. Conclusion: Our study has confirmed previous findings of GA being associated with poorer outcomes and higher mortality in patients undergoing IAT for AIS. Detailed analysis of intra-procedural hemodynamics did not reveal any significant difference between the two groups. Parenchymal hematoma was the major driver of the difference in outcomes.

The anesthetic management of ventricular septal defect (VSD) repair in a child with mitochondrial cytopathy

PurposeTo present the anesthetic management for the correction of a ventricular septal defect (VSD) in a patient with multiple acyl CoA dehydrogenase deficiency (glutaric aciduria type II; GAII). A review of the literature about anesthetic management of patients with mitochondrial diseases undergoing cardiopulmonary bypass (CPB) is also included.Clinical featuresAn 11-yr-old girl with GAII manifested as severe hypoglycemia since she was a newborn and generalized muscle weakness. She underwent open-heart surgery for VSD correction with CPB. The anesthetic management avoided inhalational anesthetics, maintained the blood sugar within normal limits and continued normothermia during CPB in order to avoid the stress of hypothermia for her abnormal mitochondria. The patient tolerated the procedure well and experienced a good recovery.ConclusionThe anesthetic management of patients with any mitochondrial disease requires normoglycemia, normothermia and the avoidance of metabolic stress in order to preserve energy production by the diseased mitochondria.RésuméObjectifPrésenter la démarche anesthésique adoptée pour la correction d’une communication interventriculaire (CIV) chez une enfant souffrant de déficience multiple d’acyl-CoA déshydrogénase (acidurie glutarique de type II; AGII). Nous incluons également une revue de la prise en charge anesthésique de patients atteints de maladies mitochondriales qui subissent une circulation extracorporelle (CEC).Éléments cliniquesUne enfant de 11 ans, atteinte d’AGII, présentait une hypoglycémie sévère depuis sa naissance et une faiblesse musculaire généralisée. Elle a subi une opération à cœur ouvert pour la correction d’une CIV sous CEC. Nous avons évité les anesthésiques d’inhalation, maintenu la glycémie dans les limites de la normale et poursuivi la normothermie pendant la CEC afin d’éviter le stress de l’hypothermie sur les anomalies mitochondriales. La patiente a bien toléré l’intervention et connu une bonne récupération.ConclusionL’anesthésie de patients atteints de maladie mitochondriale exige une normoglycémie, une normothermie et l’absence de stress dans le but de préserver la production d’énergie par les mitochondries lésées.

Recent advances in epidural analgesia.

Neuraxial anesthesia is a term that denotes all forms of central blocks, involving the spinal, epidural, and caudal spaces. Epidural anesthesia is a versatile technique widely used in anesthetic practice. Its potential to decrease postoperative morbidity and mortality has been demonstrated by numerous studies. To maximize its perioperative benefits while minimizing potential adverse outcomes, the knowledge of factors affecting successful block placement is essential. This paper will provide an overview of the pertinent anatomical, pharmacological, immunological, and technical aspects of epidural anesthesia in both adult and pediatric populations and will discuss the recent advances, the related rare but potentially devastating complications, and the current recommendations for the use of anticoagulants in the setting of neuraxial block placement.

Patient-controlled epidural analgesia (PCEA) for postoperative pain control after lumbar spine surgery.

Spine surgery remains one of the most common procedures for patients with a wide variety of spine disorders. Postoperative pain after major spine surgery is moderate to severe. We retrospectively reviewed 245 medical records of adult patients undergoing major spine surgery who received either patient-controlled epidural analgesia based on local anesthetics and opioids or patient-controlled intravenous analgesia as postoperative pain management. Several outcomes were analyzed including pain intensity, opioid consumption, time to endotracheal extubation, the incidence of deep venous thrombosis, and length of stay in the hospital. We found that the use of patient-controlled epidural analgesia provided better postoperative analgesia [median (quartiles) verbal analog scale score of 4 (3, 5) vs. 5 (3, 6)] and decreased the amount of opioid consumption postoperatively [median of 0 mg (0, 3) vs. 35 mg (0, 150)] compared with patient-controlled intravenous analgesia. Also, a substantially higher number of patients in the patient-controlled intravenous group required opioids as rescue analgesia. Incidences of deep venous thrombosis, operating room extubation, and length of stay in the hospital were not associated with the analgesic technique. The results of this study suggest that the use of neuroaxial analgesia for the management of postoperative pain associated with major spine surgery may have some beneficial properties over intravenous analgesia. The use of a reduced amount of opioids by patients with epidural analgesia may be relevant because of potential fewer side effects mainly in elderly patients. Several limitations related to the retrospective nature of the study are described. Prospective randomized-controlled trials are needed to understand and elucidate the optimum regimen of postoperative pain management after major spine surgery.