Advanced Age and Sex Influence Baseline Regional Cerebral Oxygen Saturation as Measured by Near-Infrared Spectroscopy: Subanalysis of a Prospective Study.

OBJECTIVES: The aging brain shows decreased venous oxygenation predominantly in the frontal cortex, which seems sex- dependent. The authors hypothesized that age and sex would influence baseline regional cerebral oxygen saturation (rScO2) measured by the INVOS 5100. DESIGN: Subanalysis of published data. SETTING: Tertiary hospital. PARTICIPANTS: A total of 1,616 adults undergoing cardiac interventions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Baseline rScO2 was recorded at room air and calculated as mean of the left and right rScO2. Patients were divided into 3 groups: 18- to- 49 years: young; 50- to- 74 years: middle-aged; and ≥75 years: elderly. The rScO2 was significantly different in the middle-aged (63 [56-69]) compared with the young participants (67 [59-74]; p < 0.001) and elderly participants (60 [55-66]; p < 0.001]. Women were significantly older compared with men (72 [62-79] v 66 [56-74]; p < 0.001]) and showed lower hemoglobin values (p < 0.001) and lower rScO2 (58 [52-63] v 65 [58-70]; p < 0.001]). Multiple regression analysis revealed age, sex, and hemoglobin as significant determinants of rScO2: 26.665 - (0.030 × age) + (2.581 × hemoglobin) + (2.799 × 0 for female sex). CONCLUSIONS: Baseline rScO2, as measured by the INVOS 5100, decreases with advanced age and is lower in women. New definitions of cerebral oxygen desaturation need to be analyzed in future trials that will evaluate neurologic outcome in the aging population or in women.

Predicting postoperative delirium and postoperative cognitive decline with combined intraoperative electroencephalogram monitoring and cerebral near-infrared spectroscopy in patients undergoing cardiac interventions.

Studies have associated electroencephalogram (EEG) suppression with postoperative delirium (POD) and postoperative cognitive decline (POCD). Otherwise, improving cerebral tissue oxygen saturation (rScO2) seems beneficial. No study has evaluated the impact of EEG suppression and decreased rScO2 on the incidence of POD and POCD when the intraoperative management of patients is performed with a depth-of-anesthesia (DOA) monitor and a cerebral oximetry. In this prospective study patients undergoing cardiac interventions were monitored with the NeuroSENSE® DOA monitor and bilateral cerebral oximetry. An algorithm was used to optimize cerebral oxygenation. EEG suppression was presented as total area under the curve (AUC) of suppression ratio (SR) > 0 s (AUCEEGSR>0s). Cerebral desaturation was defined as AUC of 25% drop of oximetry values as compared to baseline. POD was evaluated by the chart review method. POCD was defined as a Z-score ≤ 2 based on Mini Mental State Examination at baseline and day 5 or if the patient reported any cognitive decline at 3 and at 6 months postoperatively. Among the 1616 patients, 1513 underwent normothermic surgery and were further analyzed. POD and POCD were respectively evaluated in 1504 and 1350 patients of whom 303 (20%) and 270 (20%) were respectively diagnosed positive. Having experienced high magnitudes of EEG suppression (fourth quartile of AUCEEGSR>0s) was significantly associated with POD (OR = 2.247; 95% CI = 1.414-3.571; P = 0.001). Low rScO2 at the end of surgery was statistically associated with POCD (OR = 0.981; 95% CI = 0.965-0.997; P = 0.018). The results of our study show that the degree of intraoperative EEG suppression on one hand, and low rScO2 at the end of procedure on the other hand, are associated with respectively POD and POCD in patients undergoing cardiac interventions.

Inhaled drug delivery: a randomized study in intubated patients with healthy lungs.

BACKGROUND: The administration technique for inhaled drug delivery during invasive ventilation remains debated. This study aimed to compare in vivo and in vitro the deposition of a radiolabeled aerosol generated through four configurations during invasive ventilation, including setups optimizing drug delivery. METHODS: Thirty-one intubated postoperative neurosurgery patients with healthy lungs were randomly assigned to four configurations of aerosol delivery using a vibrating-mesh nebulizer and specific ventilator settings: (1) a specific circuit for aerosol therapy (SCAT) with the nebulizer placed at 30 cm of the wye, (2) a heated-humidified circuit switched off 30 min before the nebulization or (3) left on with the nebulizer at the inlet of the heated-humidifier, (4) a conventional circuit with the nebulizer placed between the heat and moisture exchanger filter and the endotracheal tube. Aerosol deposition was analyzed using planar scintigraphy. RESULTS: A two to three times greater lung delivery was measured in the SCAT group, reaching 19.7% (14.0-24.5) of the nominal dose in comparison to the three other groups (p < 0.01). Around 50 to 60% of lung doses reached the outer region of both lungs in all groups. Drug doses in inner and outer lung regions were significantly increased in the SCAT group (p < 0.01), except for the outer right lung region in the fourth group due to preferential drug trickling from the endotracheal tube and the trachea to the right bronchi. Similar lung delivery was observed whether the heated humidifier was switched off or left on. Inhaled doses measured in vitro correlated with lung doses (R = 0.768, p < 0.001). CONCLUSION: Optimizing the administration technique enables a significant increase in inhaled drug delivery to the lungs, including peripheral airways. Before adapting mechanical ventilation, studies are required to continue this optimization and to assess its impact on drug delivery and patient outcome in comparison to more usual settings.

Hypnosis Sedation Reduces the Duration of Different Side Effects of Cancer Treatments in Breast Cancer Patients Receiving Neoadjuvant Chemotherapy.

BACKGROUND: Reducing side effects of cancer treatments is a major challenge for clinicians involved in the management of breast cancer patients. METHODS: We analyzed data from 63 patients (32 in the general anesthesia group and 31 in the hypnosis sedation group) who were included in 1 prospective non-randomized trial evaluating hypnosis sedation in breast cancer treatment. The patients were followed every 3 months for 2 years. All patients received neoadjuvant chemotherapy with 4 cycles of epirubicin and cyclophosphamide followed by taxanes. Thereafter, patients underwent surgery while on general anesthesia or while on hypnosis sedation. Radiotherapy was administered according to institutional guidelines. Endocrine therapy was prescribed if tumors expressed hormone receptors. Prevalence, intensity and duration of polyneuropathy, musculoskeletal pain, postoperative pain and cancer-related fatigue were assessed at each medical visit. RESULTS: Symptoms duration was statistically reduced for polyneuropathy (p < 0.05), musculoskeletal pain (p < 0.05) postoperative pain and cancer-related fatigue (p < 0.05) in the hypnosis group. CONCLUSION: Despite the limitations of this study (lack of randomization and small size) we conclude that hypnosis sedation may exert a role on different side effects of breast cancer treatment in patients receiving neoadjuvant chemotherapy, mainly by reducing their duration.

Recanalization and rupture after intracranial aneurysm treatment.

BACKGROUND: Treatment of intracranial aneurysm (ICA) can sometimes require several procedures. The aim of this study was to analyze the risk of recanalization and rupture recurrence after ICA treatment by endovascular coiling (EVC) or surgical clipping (SC) on a very long follow-up. METHODS: Clinical data of 373 consecutive patients treated in our group between January 1996 and December 2006 as well by EVC as by SC for ruptured (RIA) or unruptured intracranial aneurysm (UIA), were reviewed. Patients were followed-up at least to August 2009. First radiologic follow-up done six months after EVC and between three and five years after SC (median time: 5 years). All patients underwent a clinical follow-up after treatment, at least by telephonic communication (median time: 6 years). RESULTS: Out of 197 patients with 198 RIAs, 82 (42%) patients underwent an endovascular treatment and 115 (58%) were allocated to surgical treatment. From a total of 176 patients with 229 UIAs, 66 (37.5%) patients were treated by 74 EVC; and 110 (62.5%) patients were treated with 124 surgical procedures. Fifteen recanalizations of coiled RIAs were detected and only one in the surgical group (27% vs. 2%; P= 0.0008). Of the 15 recanalizations in the EVC group, 6 (40%) were initially completely occluded. We observed two rebleedings, one in each group (1.4% for EVC; 1% for SC; P=0.8). CONCLUSIONS: Our findings during the longest reported follow-up confirm a greater risk of recanalization for RIA treated by EVC without so far a significant difference in the rerupture risk.

Electroencephalogram Suppression Despite Extremely Low-Dose Anesthetic During Cardiac Surgery: A Case Report.

A prominent feature of electroencephalogram (EEG) under general anesthesia is anteriorization of α waves. We report the case of a 63-year-old man anesthetized for coronary artery bypass grafting in whom the NeuroSENSE-processed EEG monitor recorded only δ waves in the absence of α frequencies, along with high EEG suppression despite extremely low doses of anesthetics during the whole procedure. The patient fully recovered from anesthesia 2 hours after the procedure and showed neither awareness nor neurological complications. This atypical EEG pattern under low concentration of anesthetics may be an intraoperative marker of a specific brain phenotype.

Impact of Perioperative Hypnosedation on Postmastectomy Chronic Pain: Preliminary Results.

Objectives: The main aim of this prospective nonrandomized study was to evaluate if mastectomy performed with perioperative hypnosedation led to a lower incidence of chronic pain compared with mastectomy under general anesthesia. Methods: Forty-two breast cancer patients who underwent mastectomy either under GA (GA group, n = 21) or HYP (HYP group, n = 21) associated with local and/or regional anesthesia were included. The type of adjuvant therapy as well as the number of reconstructive surgical procedures were well balanced between the 2 groups. The average age of the patients and the type of axillary surgery were also equivalent. Incidence of postmastectomy chronic pain, lymphedema, and shoulder range of motion (ROM) were evaluated after a mean 4-year follow-up. Results: The study shows a statistically significant lower incidence of postmastectomy chronic pain in HYP group (1/21, 1 patient out of 21 experiencing pain) compared with GA group (9/21) with 9 patients out of 21 experiencing pain (P = .008). ROM for shoulder was also less frequently affected in the hypnosedation group, as only 1 patient had decreased ROM, instead of 7 in the other group (P = .04). Conclusions: Our study is the first to hint at the potential benefits of hypnosedation on postmastectomy chronic pain. Despite the limitations of this study (nonrandomized, small sample), preliminary results merit further study of hypnosedation.

Aerosol delivery with two ventilation modes during mechanical ventilation: a randomized study.

BACKGROUND: Volume-controlled ventilation has been suggested to optimize lung deposition during nebulization although promoting spontaneous ventilation is targeted to avoid ventilator-induced diaphragmatic dysfunction. Comparing topographic aerosol lung deposition during volume-controlled ventilation and spontaneous ventilation in pressure support has never been performed. The aim of this study was to compare lung deposition of a radiolabeled aerosol generated with a vibrating-mesh nebulizer during invasive mechanical ventilation, with two modes: pressure support ventilation and volume-controlled ventilation. METHODS: Seventeen postoperative neurosurgery patients without pulmonary disease were randomly ventilated in pressure support or volume-controlled ventilation. Diethylenetriaminepentaacetic acid labeled with technetium-99m (2 mCi/3 mL) was administrated using a vibrating-mesh nebulizer (Aerogen Solo(®), provided by Aerogen Ltd, Galway, Ireland) connected to the endotracheal tube. Pulmonary and extrapulmonary particles deposition was analyzed using planar scintigraphy. RESULTS: Lung deposition was 10.5 ± 3.0 and 15.1 ± 5.0 % of the nominal dose during pressure support and volume-controlled ventilation, respectively (p < 0.05). Higher endotracheal tube and tracheal deposition was observed during pressure support ventilation (27.4 ± 6.6 vs. 20.7 ± 6.0 %, p < 0.05). A similar penetration index was observed for the right (p = 0.210) and the left lung (p = 0.211) with both ventilation modes. A high intersubject variability of lung deposition was observed with both modes regarding lung doses, aerosol penetration and distribution between the right and the left lung. CONCLUSIONS: In the specific conditions of the study, volume-controlled ventilation was associated with higher lung deposition of nebulized particles as compared to pressure support ventilation. The clinical benefit of this effect warrants further studies. Clinical trial registration NCT01879488.

Intraoperative 3T MRI for pituitary macroadenoma resection: Initial experience in 73 consecutive patients.

OBJECTIVE: To report a single-center experience with a 3T intraoperative magnetic resonance imaging (iMRI) to assess transsphenoidal microsurgery on pituitary macroadenomas. METHODS: In a dual, independent operating room (OR) magnetic resonance imaging (MRI) suite, the operating table with the anesthetized patient was moved on rail tracks once a supposed maximized resection was reached to the MRI room for intraoperative image acquisition and interpretation. After the assessment of the iMRI images, the neurosurgeon evaluated whether additional resection was still possible. The resection rates were assessed on iMRI and postoperative MRI at 3 months. RESULTS: A total of 73 macroadenomas benefited from an iMRI from March 2006 to October 2011. The gross total resection (GTR) rate at the time of the first iMRI was 58.9% (n=43). Based on the iMRI, eight patients (10.9%) underwent a second surgical resection. In 3 cases, the intraoperative imaging results were suspicious for a minor residue but not convincing enough for further surgery. Fortunately, the 3 months postoperative MRI control did not disclose any residual tumor in these cases. Finally, the GTR rate at the 3-month postoperative MRI increased to 72.6% (n=53). CONCLUSIONS: 3T intraoperative MRI offered excellent quality images. Its use during transsphenoidal microsurgery on pituitary macroadenomas led to an increase not only in the extent of tumor resection (in 8 patients) but also in the rate of radical resections (69% instead of 60%). No complications due to the iMRI procedure were observed.

Patients with refractory epilepsy treated using a modified multiple subpial transection technique.

BACKGROUND: : Multiple subpial transection (MST) is a potential surgical treatment for patients with epileptogenic foci located in cortical areas with higher functions. As neurosurgical teams have become more experienced with MST, the original technique has adapted. OBJECTIVE: : To report our 6-year experience with a modified MST technique. METHODS: : The population included 62 consecutive patients with medically refractory epilepsy treated by MST, with a follow-up period ranging from 2 to 9 years. MST was performed on gyri under neuronavigation and guided by intraoperative electrocorticography. We performed radiating MST from a single cortical entry point. The MST technique was described according to the number of transections performed and the Brodmann areas (BAs) involved. Any MST-related complications were registered and followed up. Clinical outcome was described in terms of seizure suppression or reduction according to the Engel modified classification. RESULTS: : Twelve patients underwent MST alone (MSTa), and 50 had MST with another procedure. The main MST sites were BA 4 (61%) and 3, 1, 2 (58%); in 22% of cases, MST was performed in BA 44, 22, 39, and 40. Permanent neurological deficits were observed in 4 (6.4%) patients; 2 minor deficits were MST related (3.2%). A reduction in the seizure rate of at least 50% was seen in 79% of patients (MSTa group, 75%), and 42% became seizure free (MSTa group, 33%). CONCLUSION: : This study demonstrates the efficacy and low morbidity of radiating MST performed under neuronavigation and intraoperative electrocorticography. ABBREVIATIONS: : BA, Brodmann areaEEG, electroencephalogramFDG, 18-fluorodeoxyglucoseioECoG, intraoperative electrocorticographyMRE, medically refractory epilepsyMST, multiple subpial transectionMSTa, multiple subpial transection aloneMST+, multiple subpial transection with other procedures.

Intraoperative magnetic resonance imaging at 3-T using a dual independent operating room-magnetic resonance imaging suite: development, feasibility, safety, and preliminary experience.

OBJECTIVE: A twin neurosurgical magnetic resonance imaging (MRI) suite with 3-T intraoperative MRI (iMRI) was developed to be available to neurosurgeons for iMRI and for independent use by radiologists. METHODS: The suite was designed with one area dedicated to neurosurgery and the other to performing MRI under surgical conditions (sterility and anesthesia). The operating table is motorized, enabling transfer of the patient into the MRI system. These two areas can function independently, allowing the MRI area to be used for nonsurgical cases. We report the findings from the first 21 patients to undergo scheduled neurosurgery with iMRI in this suite (average age, 51 +/- 24 yr; intracranial tumor, 18 patients; epilepsy surgery, 3 patients). RESULTS: Twenty-six iMRI examinations were performed, 3 immediately before surgical incision, 9 during surgery (operative field partially closed), and 14 immediately postsurgery (operative field fully closed but patient still anesthetized and draped). Minor technical dysfunctions prolonged 10 iMRI procedures; however, no serious iMRI-related incidents occurred. Twenty-three iMRI examinations took an average of 78 +/- 20 minutes to perform. In three patients, iMRI led to further tumor resection because removable residual tumor was identified. Complete tumor resection was achieved in 15 of the 18 cases. CONCLUSION: The layout of the new complex allows open access to the 3-T iMRI system except when it is in use under surgical conditions. Three patients benefited from the iMRI examination to achieve total resection. No permanent complications were observed. Therefore, the 3-T iMRI is feasible and appears to be a safe tool for intraoperative surgical planning and assessment.

Can determining the minimum alveolar anesthetic concentration of volatile anesthetic be used as an objective tool to assess antinociception in animals?

UNLABELLED: We intended to evaluate the reliability of the minimum anesthetic alveolar concentration (MAC)-sparing effect as an objective measure of the antinociceptive properties of a drug. For this purpose, we tested different variables and analyzed the significance of the results obtained. In a first set of experiments, we studied rats under mechanical ventilation and sevoflurane anesthesia. Outcome variables such as gross purposeful movements consecutive to tail clamping, paw withdrawal consecutive to increasing pressure, and cardio-circulatory reactivity (MACBAR) after these stimuli were recorded. In a second set of experiment, sevoflurane-anesthetized rats under spontaneous breathing conditions were used. Thermal stimuli were compared with pressure. The MAC-sparing effect of several doses of sufentanil and clonidine was evaluated in both anesthetized and awake rodents. When considering the stimulus applied, larger concentrations of sevoflurane were required to suppress reactivity after tail clamp than after paw pressure or radiant heat (1.81 +/- 0.28 versus 1.45 +/- 0.22 and 1.53 +/- 0.26; P < 0.05). For the two first stimuli, no significant differences were noted between the concentrations that suppress motor or cardio-circulatory reactions. All doses of sufentanil tested significantly reduced (P < 0.05) the different MAC values except the smallest one (0.005 micro g x kg(-1) x min(-1)) that significantly increased MACBAR in ventilated animals and both MAC and MACBAR in spontaneously breathing rodents (P < 0.05). Clonidine, at its optimal dose (10 micro g/kg), significantly reduced both MAC and MACBAR to the same degree. In awake animals submitted to radiant heat or pressure challenge, none of the clonidine doses nor sufentanil doses (0.005 and 0.07) were active. In conclusion, the MAC-sparing effect provides several reliable and quantifiable variables that allow comparison between different analgesic substances. However, the observations made are not simply the result of antinociceptive effects of the tested drugs but rather that of complex interactions between these drugs and a halogenated vapor. IMPLICATIONS: The MAC-sparing effect provides several variables that allow comparison between different analgesic substances. However, the observations made are not simply the result of the antinociceptive effects of the tested drugs but rather the result of complex interactions between these drugs and a halogenated vapor.

Spinal alpha(2)-adrenoceptors are involved in the MACbar-sparing effect of systemic clonidine in rats.

UNLABELLED: We evaluated the central or spinal mechanism involved in the MACbar-sparing effect of systemic clonidine by using intrathecal alpha-adrenergic antagonist administration. The minimum alveolar concentration of sevoflurane that blocks cardiovascular response to a noxious stimulus (MACbar(sevo)) was determined in rats after treatment with IV saline, IV clonidine 10 micro g/kg, intrathecal (IT) or IV phentolamine 50 micro g, IT or IV yohimbine 200 micro g, IT or IV prazosin 30 micro g, or the combination of IV clonidine and the different IT or IV alpha-adrenergic antagonists. In the studied model, the MACbar(sevo) of saline-treated controls was 2.10 +/- 0.8. After clonidine administration, it decreased to 1.07 +/- 0.4. The IT administration of phentolamine and yohimbine did not modify the MACbar(sevo) of naïve rats, whereas in IV clonidine-treated animals, it totally suppressed the MAC-sparing effect of this drug (phentolamine) or even significantly increased (yohimbine) the MACbar(sevo) (2.78 +/- 1) when compared with controls (P < 0.05). IT prazosin alone significantly reduced the MACbar(sevo) (0.35 +/- 0.3; P< 0.05) and suppressed any hemodynamic reaction when combined with IV clonidine. The IV administration of the different alpha-adrenergic antagonists had no significant effect on the MACbar(sevo) of controls or IV clonidine-treated animals. These results argue for a spinal mechanism of action involved in the MACbar-sparing effect of systemic clonidine. Moreover, the spinally administered alpha-antagonists displayed different effects in rats under sevoflurane anesthesia than those reported in awake animals. IMPLICATIONS: Using intrathecal alpha-adrenergic antagonist administration, we demonstrated that a spinal mechanism is involved in the MACbar-sparing effect of systemic clonidine in rats.