Cardiac output changes after osmotic therapy in neurosurgical and neurocritical care patients: a systematic review of the clinical literature.

AIM: Osmotherapy constitutes a first-line intervention for intracranial hypertension management. However, hyperosmolar solutes exert various systematic effects, among which their impact on systemic haemodynamics is poorly clarified. This review aims to appraise the clinical evidence of the effect of mannitol and hypertonic saline (HTS) on cardiac performance in neurosurgical and neurocritical care patients. METHOD: A database search was conducted to identify randomized clinical trials and observational studies reporting HTS or mannitol use in acute brain injury setting. The primary end-points were alterations of cardiac output (CO) and other haemodynamic variables, while the impact of osmotic agents on intracranial pressure, brain relaxation, plasma osmolality, electrolyte levels and urinary output constituted secondary outcomes. RESULTS: Eight studies, enrolling 182 patients in total, were included. HTS exerted a more profound cardiac output augmentation than mannitol, but no distinct difference between groups occurred. Central venous pressure, stroke volume and stroke volume variation were favourably affected by both osmotic agents, whilst the reported changes in blood pressure were inconclusive. HTS infusion yielded a larger intracranial pressure reduction than mannitol but had an equivalent effect on brain relaxation. Mannitol presented a more potent diuretic effect than HTS. Effect on serum osmolality was alike in both osmotic agents, but contrary to HTS-promoted hypernatraemia, mannitol use induced transient hyponatraemia. CONCLUSIONS: Mannitol or HTS administration seems to induce an enhancement of cardiac performance; being more prominent after HTS infusion. This effect combined with mannitol-induced enhancement of diuresis and HTS-promoted increase of plasma sodium concentration could partially explain the effects of osmotherapy on cerebral haemodynamics.

Diagnostic work up for language testing in patients undergoing awake craniotomy for brain lesions in language areas.

Awake craniotomy is the technique of choice in patients with brain tumours adjacent to primary and accessory language areas (Broca's and Wernicke's areas). Language testing should be aimed to detect preoperative deficits, to promptly identify the occurrence of new intraoperative impairments and to establish the course of postoperative language status. Aim of this case series is to describe our experience with a dedicated language testing work up to evaluate patients with or at risk for language disturbances undergoing awake craniotomy for brain tumour resection. Pre- and intra operative testing was accomplished with 8 tests. Intraoperative evaluation was accomplished when patients were fully cooperative (Ramsey < 3). Postoperative evaluation was scheduled at early (within 21 days) and long-term follow-up (3-6 months). Twenty consecutive patients were prospectively recruited. Preoperative language testings were normal in 9 patients (45%), showed mild to moderate language deficit in 8 (40%) and severe language deficit or aphasic disorders in 3 (15%). Broca's area was identified in 15 patients, in all cases by counting arrest during stimulation and in 12 cases by naming arrest. In this article we describe our experience using a language testing work up to evaluate - pre, intra and postoperatively - patients undergoing awake craniotomy for brain tumour resection with preoperative language disturbances or at risk for postoperative language deficits. This approach allows a systematic evaluation and recording of language function status and can be accomplished even when a neuropsychologist or speech therapist are not involved in the operation crew.

Ultrasound imaging and use of B-lines for functional lung evaluation in neurocritical care: a prospective, observational study.

CONTEXT: Lung ultrasound imaging can be used to evaluate pulmonary water content and pulmonary consolidation in ICU patients, but data from neurocritical care are lacking. OBJECTIVE: To evaluate the utility of lung ultrasound to estimate the PaO2/FiO2 ratio and its diagnostic accuracy compared with chest radiograph and thoracic computed tomography (CT). DESIGN: Prospective, observational study. SETTING: University hospital neurocritical care unit. PATIENTS: Forty-five consecutive patients. MAIN OUTCOME MEASURES: The relationship between the number of B-lines and the PaO2/FiO2 ratio as measure of lung water content, and the diagnosis of pulmonary consolidation. RESULTS: Evaluation of lung water content as determined by the number of 'B-lines' has a linear relationship with the PaO2/FiO2 ratio (r = -0.8; P < 0.01). Lung ultrasound has a diagnostic accuracy similar to that of chest radiograph (99 vs. 96%), using thoracic CT as the reference technique. CONCLUSION: In neurocritical care, the use of lung ultrasound allows detection of increased lung water content when more than three 'B-lines' are present within the same lung field. This is associated with a reduction in PaO2/FiO2 ratio. Lung ultrasound can be used to diagnose pulmonary consolidation with an accuracy similar to the chest radiograph.

Potassium sparing diuretics as adjunct to mannitol therapy in neurocritical care patients with cerebral edema: effects on potassium homeostasis and cardiac arrhythmias.

BACKGROUND: Mannitol therapy to treat cerebral edema induces osmotic diuresis and electrolyte loss. In neurocritical care patients, potassium is the electrolyte that most often needs replacement. Objective of this study was to evaluate the effects of adding potassium sparing diuretic (canrenone) to mannitol therapy on potassium urinary excretion, potassium plasma levels, and incidence of new cardiac arrhythmias in patients receiving neurocritical care for cerebral edema. METHODS: Fifty-six patients were prospectively assigned to mannitol or mannitol plus i.v. canrenone. Potassium urinary excretion, potassium plasma levels, urinary volume, and the incidence of new cardiac arrhythmias were recorded during the first 8 days of therapy. RESULTS: In patients treated with mannitol the potassium urinary excretion was stable over the first 3 days and significantly increased, compared to baseline, on day 4th to 8th (baseline 20.3 ± 10.6 mEq/l/die, day 8th 24.6 ± 10.6 mEq/l/die, P < 0.05); while potassium plasma levels significantly decreased. In patients receiving mannitol plus canrenone potassium urinary excretion decreased from day 3rd to 8th (baseline 21.9 ± 11.6 mEq/l/die, day 8th 15.9 ± 10.9 mEq/l/die, P < 0.015) and potassium plasma levels increased but remained within normal values range. The incidence of new cardiac arrhythmias was higher in the mannitol group than the mannitol plus canrenone group (35.7 vs. 10.7%; P < 0.01). Urinary volumes, potassium balance, and sodium plasma concentration were similar in the 2 study groups. CONCLUSION: In patients receiving neurocritical care for cerebral edema, the adjunct of a potassium sparing diuretic (canrenone) to mannitol therapy reduces potassium urinary loss, prevents hypokalemia, and reduces the incidence of new cardiac arrhythmias.

Language testing during awake "anesthesia" in a bilingual patient with brain lesion adjacent to Wernicke's area.

Awake "anesthesia" is the preferable anesthetic approach for neurosurgical procedures that require intraoperative localization of eloquent brain areas. We describe intraoperative inducible selective English aphasia in a bilingual (English and Italian) patient undergoing awake anesthesia for excision of a brain lesion adjacent to Wernicke's area with no postoperative neurological sequelae. We discuss the importance of intraoperative brain mapping and intraoperative language testing in bilingual patients to prevent iatrogenic-related morbidity.

Cerebrospinal Fluid Glucose and Lactate Levels After Subarachnoid Hemorrhage: A Multicenter Retrospective Study.

BACKGROUND: In patients with subarachnoid hemorrhage (SAH), abnormalities in glucose and lactate metabolism have been described using cerebral microdialysis. Glucose and lactate concentrations in cerebrospinal fluid (CSF) are more easily accessible, but scarce data are available in this setting. The aim of this study is to assess the relationship of CSF glucose and lactate with blood concentrations and with unfavorable neurological outcome after SAH. METHODS: A retrospective cohort study was conducted in 5 European University intensive care units. Patients aged 18 years and above who were admitted after a nontraumatic SAH over a 4-year period (2011 to 2014) were included if they had an external ventricular drain placed, daily analysis of CSF including glucose (±lactate) concentrations for 1 to 4 consecutive days, and concomitant analysis of glucose and lactate concentrations in the arterial blood. RESULTS: A total of 144 patients were included in the final analysis (median age: 58 [49 to 66] y; male sex: 77/144). Median time from admission to external ventricular drain placement was 1 (0 to 3) day; median Glasgow Coma Scale on admission was 10 (7 to 13), and CT-scan Fisher scale was 4. A total of 81 (56%) patients had unfavorable neurological outcome at 3 months (Glasgow Outcome Scale ≤3). There was a weak correlation between blood and CSF glucose (r=0.07, P=0.007), and between blood and CSF lactate levels (r=0.58, P<0.001) on day 1, which were not influenced by insulin therapy. The presence of shock and low CSF glucose/lactate ratio were the only independent predictors of unfavorable outcome. CONCLUSIONS: CSF glucose and lactate levels poorly correlated with blood concentrations. Low CSF glucose/lactate ratio was associated with poor neurological outcome.

Neuroprotective effects of intravenous anesthetics: a new critical perspective.

Perioperative cerebral damage can result in various clinical sequela ranging from minor neurocognitive deficits to catastrophic neurological morbidity with permanent impairment and death. The goal of neuroprotective treatments is to reduce the clinical effects of cerebral damage through two major mechanisms: increased tolerance of neurological tissue to ischemia and changes in intra-cellular responses to energy supply deprivation. In this review, we present the clinical evidence of intravenous anesthetics on perioperative neuroprotection, and we also provide a critical perspective for future studies. The neuroprotective efficacy of the intravenous anesthetics thiopental, propofol and etomidate is unproven. Lidocaine may be neuroprotective in non-diabetic patients who have undergoing cardiac surgery with cardiopulmonary bypass (CBP) or with a 48-hour infusion, but conclusive data are lacking. There are several limitations of clinical studies that evaluate postoperative cognitive dysfunction (POCD), including difficulties in identifying patients at high-risk and a lack of consensus for defining the "gold-standard" neuropsychological testing. Although a battery of neurocognitive tests remains the primary method for diagnosing POCD, recent evidence suggests a role for novel biomarkers and neuroimaging to preemptively identify patients more susceptible to cognitive decline in the perioperative period. Current evidence, while inconclusive, suggest that intravenous anesthetics may be both neuroprotective and neurotoxic in the perioperative period. A critical analysis on data recorded from randomized control trials (RCTs) is essential in identifying patients who may benefit or be harmed by a particular anesthetic. RCTs will also contribute to defining methodologies for future studies on the neuroprotective effects of intravenous anesthetics.

Training anesthesiology residents in providing anesthesia for awake craniotomy: learning curves and estimate of needed case load.

STUDY OBJECTIVE: To measure the learning curves of residents in anesthesiology in providing anesthesia for awake craniotomy, and to estimate the case load needed to achieve a "good-excellent" level of competence. DESIGN: Prospective study. SETTING: Operating room of a university hospital. SUBJECTS: 7 volunteer residents in anesthesiology. MEASUREMENTS: Residents underwent a dedicated training program of clinical characteristics of anesthesia for awake craniotomy. The program was divided into three tasks: local anesthesia, sedation-analgesia, and intraoperative hemodynamic management. The learning curve for each resident for each task was recorded over 10 procedures. Quantitative assessment of the individual's ability was based on the resident's self-assessment score and the attending anesthesiologist's judgment, and rated by modified 12 mm Likert scale, reported ability score visual analog scale (VAS). This ability VAS score ranged from 1 to 12 (ie, very poor, mild, moderate, sufficient, good, excellent). The number of requests for advice also was recorded (ie, resident requests for practical help and theoretical notions to accomplish the procedures). MAIN RESULTS: Each task had a specific learning rate; the number of procedures necessary to achieve "good-excellent" ability with confidence, as determined by the recorded results, were 10 procedures for local anesthesia, 15 to 25 procedures for sedation-analgesia, and 20 to 30 procedures for intraoperative hemodynamic management. CONCLUSIONS: Awake craniotomy is an approach used increasingly in neuroanesthesia. A dedicated training program based on learning specific tasks and building confidence with essential features provides "good-excellent" ability.

Early postoperative cognitive dysfunction and postoperative delirium after anaesthesia with various hypnotics: study protocol for a randomised controlled trial--the PINOCCHIO trial.

BACKGROUND: Postoperative delirium can result in increased postoperative morbidity and mortality, major demand for postoperative care and higher hospital costs. Hypnotics serve to induce and maintain anaesthesia and to abolish patients' consciousness. Their persisting clinical action can delay postoperative cognitive recovery and favour postoperative delirium. Some evidence suggests that these unwanted effects vary according to each hypnotic's specific pharmacodynamic and pharmacokinetic characteristics and its interaction with the individual patient.We designed this study to evaluate postoperative delirium rate after general anaesthesia with various hypnotics in patients undergoing surgical procedures other than cardiac or brain surgery. We also aimed to test whether delayed postoperative cognitive recovery increases the risk of postoperative delirium. METHODS/DESIGN: After local ethics committee approval, enrolled patients will be randomly assigned to one of three treatment groups. In all patients anaesthesia will be induced with propofol and fentanyl, and maintained with the anaesthetics desflurane, or sevoflurane, or propofol and the analgesic opioid fentanyl.The onset of postoperative delirium will be monitored with the Nursing Delirium Scale every three hours up to 72 hours post anaesthesia. Cognitive function will be evaluated with two cognitive test batteries (the Short Memory Orientation Memory Concentration Test and the Rancho Los Amigos Scale) preoperatively, at baseline, and postoperatively at 20, 40 and 60 min after extubation.Statistical analysis will investigate differences in the hypnotics used to maintain anaesthesia and the odds ratios for postoperative delirium, the relation of early postoperative cognitive recovery and postoperative delirium rate. A subgroup analysis will be used to categorize patients according to demographic variables relevant to the risk of postoperative delirium (age, sex, body weight) and to the preoperative score index for delirium. DISCUSSION: The results of this comparative anaesthesiological trial should whether each the three hypnotics tested is related to a significantly different postoperative delirium rate. This information could ultimately allow us to select the most appropriate hypnotic to maintain anaesthesia for specific subgroups of patients and especially for those at high risk of postoperative delirium. REGISTERED AT TRIAL.GOV NUMBER: ClinicalTrials.gov: NCT00507195.

Postoperative cognitive dysfunction: toward the Alzheimer's disease pathomechanism hypothesis.

Alzheimer's disease (AD), a chronic and progressive deterioration of memory and other cognitive domains, is the most common form of dementia. Because of related health and social impact, there is growing interest in assessing potential relationship between anesthesia and the onset and progression of chronic neurodegenerative disorders, including AD. Currently, preclinical and clinical research is addressed to identify underlying pathomechanisms, patient risk factors, and the use of the least provocative drugs and techniques, to minimize the incidence of chronic neurodegenerative disorders. Preclinical studies are providing an increasing body of evidences on some of the mechanisms that link anesthetics to neuronal programmed cell death (apoptosis) and accumulation of misfolded proteins in the aging brain. Therefore, risk factors and pathomechanisms of chronic neurodegenerative disorders, including AD, and persistent postoperative-postanesthesia cognitive dysfunction may overlap.