Awake Group Research Articles

Clinical outcomes following awake and asleep deep brain stimulation for Parkinson disease.

Recent studies have shown similar clinical outcomes between Parkinson disease (PD) patients treated with deep brain stimulation (DBS) under general anesthesia without microelectrode recording (MER), so-called “asleep” DBS, and historical cohorts undergoing “awake” DBS with MER guidance. However, few studies include internal controls. This study aims to compare clinical outcomes after globus pallidus internus (GPi) and subthalamic nucleus (STN) DBS using awake and asleep techniques at a single institution. PD patients undergoing awake or asleep bilateral GPi or STN DBS were prospectively monitored. The primary outcome measure was stimulation-induced change in motor function off medication 6 months postoperatively, measured using the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III). Secondary outcomes included change in quality of life, measured by the 39-item Parkinson’s Disease Questionnaire (PDQ-39), change in levodopa equivalent daily dosage (LEDD), stereotactic accuracy, stimulation parameters, and adverse events. Six-month outcome data were available for 133 patients treated over 45 months (78 GPi [16 awake, 62 asleep] and 55 STN [14 awake, 41 asleep]). UPDRS-III score improvement with stimulation did not differ between awake and asleep groups for GPi (awake, 20.8 points [38.5%]; asleep, 18.8 points [37.5%]; p = 0.45) or STN (awake, 21.6 points [40.3%]; asleep, 26.1 points [48.8%]; p = 0.20) targets. The percentage improvement in PDQ-39 and LEDD was similar for awake and asleep groups for both GPi (p = 0.80 and p = 0.54, respectively) and STN cohorts (p = 0.85 and p = 0.49, respectively). In PD patients, bilateral GPi and STN DBS using the asleep method resulted in motor, quality-of-life, and medication reduction outcomes that were comparable to those of the awake method.

Functional connectivity under six anesthesia protocols and the awake condition in rat brain

Resting-state functional magnetic resonance imaging (rsfMRI) is a translational imaging method with great potential in several neurobiologic applications. Most preclinical rsfMRI studies are performed in anesthetized animals, but the confounding effects of anesthesia on the measured functional connectivity (FC) are poorly understood. Therefore, we measured FC under six commonly used anesthesia protocols and compared the findings with data obtained from awake rats. The results demonstrated that each anesthesia protocol uniquely modulated FC. Connectivity patterns obtained under propofol and urethane anesthesia were most similar to that observed in awake rats. FC patterns in the α-chloralose and isoflurane-medetomidine combination groups had moderate to good correspondence with that in the awake group. The FC patterns in the isoflurane and medetomidine groups differed most from that in the awake rats. These results can be directly exploited in rsfMRI study designs to improve the data quality, comparability, and interpretation.

Deep or awake removal of laryngeal mask airway in children at risk of respiratory adverse events undergoing tonsillectomy—a randomised controlled trial

BackgroundLaryngeal mask airways (LMA) are widely used during tonsillectomies. Contrasting evidence exists regarding the timing of the removal and the risk of perioperative respiratory adverse events. We assessed whether the likelihood of perioperative respiratory adverse events is influenced by the timing of LMA removal in children with at least one risk factor for these events. MethodsParticipants (n=290, 0–16 yr) were randomised to have their LMA removed either deep (in theatre by anaesthetist at end-tidal sevoflurane >1 minimum alveolar concentration) or awake (in theatre by anaesthetist or in postanaesthesia care unit by anaesthetist or trained nurse). The primary outcome was the occurrence of perioperative respiratory adverse events over the whole emergence and postanaesthesia care unit phases of anaesthesia. The secondary outcome was the occurrence of perioperative respiratory adverse events over the distinct phases of emergence and postanaesthesia care unit. ResultsData from 283 participants were analysed. Primary outcome: even though a higher occurrence of adverse events was observed in the awake group, no evidence for a difference was found [45% vs 35%, odds ratio (OR): 1.5, 95% confidence interval (CI): 0.9–2.5, P=0.09]. Secondary outcome: there was no evidence for a difference between the groups during emergence [19 (14%) deep vs 25 (18%) awake, OR: 0.74, 95%CI: 0.39–1.42, P=0.37]. However, in the postanaesthesia care unit, children with an awake rather than deep removal experienced significantly more adverse events [55 (39%) vs 37 (26%); OR: 1.85, 95%CI: 1.12–3.07, P=0.02]. ConclusionWe found no evidence for a difference in the timing of the LMA removal on the incidence of respiratory adverse events over the whole emergence and postanaesthesia care unit phases. However, in the postanaesthesia care unit solely, awake removal was associated with significantly more respiratory adverse events than deep removal. Trial registration numberACTRN12609000387224 (www.anzctr.org.au).

Conscious Sedation with Dexmedetomidine in Awake Surgery

Background: It is well demonstrated that awake surgery for brain tumours is the gold standard to achieve the maximal safe resection. On the other hand, many surgeons prefer general anesthesia in order to avoid useless stress for patients. The aim of our paper is to investigate if there are clinical and biochemical findings demonstrating a different stress level in patients who underwent awake craniotomy compared to those who underwent totally asleep surgery. Methods: We compared our awake craniotomy series performed with conscious sedation using Dexmedetomidine to a group of patients treated in general anesthesia settings in terms of patient stress, rated by blood pressure, heart rate, glycaemia, lactate values, post-operative ischemia or bleeding at the MRI. We also compared the duration of surgeries in the two groups and the relations between time and other parameters. Results: We found that preoperative heart rate was higher in the awake group (63.00 (SD13.58) vs. 76.5 (SD 14.34) p value 0.025) together with preoperative systolic blood pressure 122 (SD 12.95 vs. 135.1 SD (11.78) p value 0.044). However there were no clinical, biochemical and radiological differences in post-operative period in the two groups, suggesting the efficacy of Dexmedetomidine in stress control. It is demonstrated a cause-effect relation between the duration of surgery and the raising of blood pressure, suggesting that conscious sedation can reduce useless anesthesiological time in the awake surgery setting. Conclusions: We showed that the two anesthetic settings are similar in terms of stress parameters after surgery. This finding could be confirmed in a prospective study with a higher number of patients.

217 Clinical Outcomes Following Awake and Asleep Deep Brain Stimulation for Parkinson's Disease

Abstract INTRODUCTION Recent studies show similar clinical outcomes in Parkinson's disease (PD) patients treated by deep brain stimulation (DBS) under general anesthesia without microelectrode recording (MER), so-called “asleep” DBS, compared to historical cohorts undergoing “awake” DBS with MER guidance. Very few studies, however, include internal controls. This study compares clinical outcomes following globus pallidus interna (GPi) and subthalamic nucleus (STN) DBS using awake and asleep techniques at a single institution. METHODS PD patients undergoing awake or asleep bilateral GPi or STN DBS were prospectively followed. The primary outcome measure was stimulation-induced change in motor function 6 months postoperatively, measured by the Unified Parkinson's Disease Rating Scale part III (UPDRS-III) with the patient off medication. Secondary outcomes included change in quality of life, measured by the 39-item Parkinson's Disease Questionnaire (PDQ-39), change in levodopa daily equivalent dose (LEDD), stereotactic accuracy, stimulation parameters, and adverse events. RESULTS >Six-month outcome data were available for 133 patients treated over 45 months (78 GPi [16 awake, 62 asleep] and 55 STN [14 awake and 41 asleep]). UPDRS-III score improvement with stimulation did not differ between awake and asleep groups for GPi (awake = 20.8 points [38.5%], asleeP = 18.8 points [37.5%], P = 0.45) or STN (awake = 21.6 points [40.3%], asleeP = 26.1 points [48.8%], P = 0.20) targets. The percentage improvement in PDQ-39 and LEDD was similar for awake and asleep groups for both GPi (P = 0.80, P = 0.54, respectively) and STN cohorts (P = 0.85, P = 0.49, respectively). CONCLUSION In PD patients, bilateral GPi and STN DBS utilizing the asleep method resulted in motor, quality-of-life, and medication reduction outcomes comparable to the awake method.

The choice between surgical scrubbing and sterile covering before or after induction of anaesthesia: A prospective study.

Background : Day surgery is increasing, and safe and effective logistics are sought. One part of the in-theatre logistics commonly discussed is whether surgical scrub and sterile covering should be done before or after induction of anaesthesia. The aim of the present study was to compare the impact of surgical scrub and sterile covering before vs. after the induction of anaesthesia in male patients scheduled for open hernia repair. Methods : This is a prospective randomised study. Sixty ASA 1-3 patients scheduled for open hernia repair were randomised to surgical scrub and sterile covering before or after induction of anaesthesia; group "awake" and "anaesthetised". Need for vasoactive medication during anaesthesia was primary study objective. Duration of anaesthesia and surgery, theatre time, recovery room stay and time to discharge, patients and theatre nurses experiences and willingness to have the same logistics on further potential surgeries, by a questionnaire provided before discharge was also assessed. Results : The duration of anaesthesia was shorter and doses of propofol and remifentanil were reduced by 10 and 13%, respectively, in the awake group. We found still no difference in the need for vasoactive medication during anaesthesia Time in recovery area was significantly reduced in the awake group 39 (SD 15) vs. 48 SD 16) (p<0.05), but time to discharge was not different. There was further no difference in the patients' assessment of quality of care, and only one patient in the awake group would prefer to be anaesthetised on a future procedure. All nurses found pre-anaesthesia scrubbing acceptable as routine. Conclusion : Surgical scrub and sterile covering before the induction of anaesthesia can be done safely and without jeopardising patients' quality of care and possibly improve perioperative logistics. Further studies are warranted assessing impact of awake scrubbing and sterile covering on quality and efficacy of perioperative care.

The choice between surgical scrubbing and sterile covering before or after induction of anaesthesia: A prospective study

Background: Day surgery is increasing, and safe and effective logistics are sought. One part of the in-theatre logistics commonly discussed is whether surgical scrub and sterile covering should be done before or after induction of anaesthesia. The aim of the present study was to compare the impact of surgical scrub and sterile covering before vs. after the induction of anaesthesia in male patients scheduled for open hernia repair. Methods: This is a prospective randomised study. Sixty ASA 1-3 patients scheduled for open hernia repair were randomised to surgical scrub and sterile covering before or after induction of anaesthesia; group “awake” and “anaesthetised”. Need for vasoactive medication during anaesthesia was primary study objective. Duration of anaesthesia and surgery, theatre time, recovery room stay and time to discharge, patients and theatre nurses experiences and willingness to have the same logistics on further potential surgeries, by a questionnaire provided before discharge was also assessed. Results: The duration of anaesthesia was shorter and doses of propofol and remifentanil were reduced by 10 and 13%, respectively, in the awake group. We found still no difference in the need for vasoactive medication during anaesthesia Time in recovery area was significantly reduced in the awake group 39 (SD 15) vs. 48 SD 16) (p<0.05), but time to discharge was not different. There was further no difference in the patients’ assessment of quality of care, and only one patient in the awake group would prefer to be anaesthetised on a future procedure. All nurses found pre-anaesthesia scrubbing acceptable as routine. Conclusion: Surgical scrub and sterile covering before the induction of anaesthesia can be done safely and without jeopardising patients’ quality of care and possibly improve perioperative logistics. Further studies are warranted assessing impact of awake scrubbing and sterile covering on quality and efficacy of perioperative care.

The choice between surgical scrubbing and sterile covering before or after induction of anaesthesia: A prospective study

Background: Day surgery is increasing, and safe and effective logistics are sought. One part of the in-theatre logistics commonly discussed is whether surgical scrub and sterile covering should be done before or after induction of anaesthesia. The aim of the present study was to compare the impact of surgical scrub and sterile covering before vs. after the induction of anaesthesia in male patients scheduled for open hernia repair. Methods: This is a prospective randomised study. Sixty ASA 1-3 patients scheduled for open hernia repair were randomised to surgical scrub and sterile covering before or after induction of anaesthesia; group "awake" and group "anaesthetised", respectively. Patients and theatre nurses were asked about their experiences and willingness to have the same logistics on further potential surgeries, through a survey provided before post-surgery. Duration of anaesthesia, surgery, theatre time, recovery room stay and time to discharge was studied. Results: There was no difference in the patients' assessment of quality of care, and only one patient in the awake group would prefer to be anaesthetised on a future procedure. All nurses found pre-anaesthesia scrubbing acceptable as routine. The duration of anaesthesia was shorter and doses of propofol and remifentanil were reduced by 10 and 13%, respectively, in the awake group. Time in recovery area was significantly reduced in the awake group (p<0.05), but time to discharge was not different. Conclusion: Surgical scrub and sterile covering before the induction of anaesthesia can be done safely and without jeopardising patients' quality of care.

0138 DIFFERENTIAL C-FOS EXPRESSION IN GABAERGIC NEURONS OF THE NUCLEUS PONTIS ORALIS DURING WAKEFULNESS AND CARBACHOL-INDUCED ACTIVE SLEEP

Previous studies have demonstrated that GABAergic processes in the nucleus pontis oralis (NPO) play an important role in the generation and maintenance of active sleep and wakefulness. However, the location of cell bodies and neural activity of this pontine GABAergic system during wakefulness and active sleep are unknown. Accordingly, the present study was undertaken to determine the distribution of activated GABAergic neurons within the NPO during wakefulness and carbachol-induced active sleep (active sleep-carbachol) using c-Fos immunocytochemistry as a functional marker of neuronal activity. Adult cats that were prepared for monitoring behavioral states were used in this experiment. In the awake group, animals were kept awake for 2 hours following the microinjection of saline into the NPO before being euthanized. In the active sleep-carbachol group, animals were euthanized after prolonged episodes of active sleep that was induced by the microinjection of carbachol into the NPO. Subsequently, brainstem sections were immunostained with a GABA antiserum in addition to a Fos polyclonal antiserum in order to double-label neurons that were both GABAergic and Fos immunoreactive. In awake cats, there was a large number of GABAedrgic neurons that expressed c-Fos in the NPO. These GABA+/c-Fos+ neurons were small to medium-sized and were located mainly within the lateral part of the NPO. In contrast, in active sleep-carbachol cats, the numbers of c-Fos expressing GABAergic neurons were decreased in the NPO. Specifically, there were only few GABAergic neurons in the lateral part of the NPO that expressed c-Fos during active sleep-carbachol. The present results demonstrate that there exists a discrete group of GABAergic neurons in the NPO that are activated during wakefulness and inactivated during active sleep. We therefore suggest that these local GABAergic cells may be the neurons that comprise the pontine GABAergic system which functions to promote wakefulness and suppress active sleep by inhibiting active sleep-generator neurons in the NPO during wakefulness and disinhibiting them during active sleep. NS092383.

Pathogenic Link Between Postextubation Pneumonia and Ventilator-Associated Pneumonia: An Experimental Study

The presence of an endotracheal tube is the main cause for developing ventilator-associated pneumonia (VAP), but pneumonia can still develop in hospitalized patients after endotracheal tube removal (postextubation pneumonia [PEP]). We hypothesized that short-term intubation (24 hours) can play a role in the pathogenesis of PEP. To test such hypothesis, we initially evaluated the occurrence of lung colonization and VAP in sheep that were intubated and mechanically ventilated for 24 hours. Subsequently, we assessed the incidence of lung colonization and PEP at 48 hours after extubation in sheep previously ventilated for 24 hours. To simulate intubated intensive care unit patients placed in semirecumbent position, 14 sheep were intubated and mechanically ventilated with the head elevated 30° above horizontal. Seven of them were euthanized after 24 hours (Control Group), whereas the remaining were euthanized after being awaken, extubated, and left spontaneously breathing for 48 hours after extubation (Awake Group). Criteria of clinical diagnosis of pneumonia were tested. Microbiological evaluation was performed on autopsy in all sheep. Only 1 sheep in the Control Group met the criteria of VAP after 24 hours of mechanical ventilation. However, heavy pathogenic bacteria colonization of trachea, bronchi, and lungs (range, 10-10 colony-forming unit [CFU]/g) was reported in 4 of 7 sheep (57%). In the Awake Group, 1 sheep was diagnosed with VAP and 3 developed PEP within 48 hours after extubation (42%), with 1 euthanized at 30 hours because of respiratory failure. On autopsy, 5 sheep (71%) confirmed pathogenic bacterial growth in the lower respiratory tract (range, 10-10 CFU/g). Twenty-four hours of intubation and mechanical ventilation in semirecumbent position leads to significant pathogenic colonization of the lower airways, which can promote the development of PEP. Strategies directed to prevent pathogenic microbiological colonization before and after mechanical ventilation should be considered to avert the onset of PEP.

P16.22 Awake-Awake-Awake with dexmedetomidine compared to asleep-awake-asleep craniotomies in glioma surgery - an analysis from 180 glioma patients

Abstract Introduction: For over 70 years, awake craniotomies have been part of treatment of gliomas located in so called “eloquent regions”. The patients’ compliance plays an important role in the success of each surgery. Finding the optimal balance between dosage and type of sedative, analgesic and anxiolytic drugs and keeping the patient clinically and neurologically assessable remains challenging. Different techniques are applied in neurooncology centres: “Asleep-awake-asleep” and “awake-awake-awake” are both techniques which have been used at the Department of Neurosurgery, University Hospital of Munster. Since 2013, we performed solely “awake-awake-awake” surgeries using the a2-receptor agonist, dexmedetomidine, as sole anaesthetic drug. The aim of this study was to compare both techniques and evaluate the clinical use of dexmedetomidine in the setting of awake craniotomies for glioma surgery. Material and methods: We retrospectively analysed patients that were operated in the Department of Neurosurgery, University Hospital of Muenster either under “asleep-awake-asleep” using propofol-remifentanil sedation, or under “awake-awake-awake” conditions, using dexmedetomidine infusions. In the,,asleep-awake-asleep”- group patients were intubated with laryngeal mask and extubated for the assessment period. Patients in the fully awake group were sedated with dexmedetomidine beyond the test phase. A scalp block was used in both conditions. We evaluated the electronical medical record and the digitalized anesthetic protocols from each patient. Adverse events, as well as applied drugs with doses and frequency of usage were recorded. Compliance was evaluated according to the surgeons’ perception. Results: Two-hundred twenty-four (n=224) awake surgeries were performed in the period from October 2009 till September 2015. One-hundred eighty (n=180) of these were performed for the resection of gliomas and included into the study. In the “awake-awake-awake”- group (n=75) significantly less opiates (p<0.000), less vasoactive (p<0.000) and antihypertensive (p<0.000) drugs were used in comparison to the “asleep-awake-asleep”- group (n=105). In addition, compliance was much higher rated in the “awake-awake-awake”-group. Furthermore, the overall length of stay (p<0.000) and the surgical time (p<0.000) was significantly lower in the “awake-awake-awake” group. Conclusions: Dexmedetomidine provides excellent setting for fully awake surgeries. Our experience shows that using dexmedetomidine as sole anaesthetic drug during awake craniotomies sedates moderately and acts anxiolytic. Thus, after ceasing infusion it enables quick and reliable clinical neurological assessment of patients. Furthermore, according to our experience, it reduces the length of hospital stay and duration of the whole surgical procedure.

Comparison of Hemodynamic Response and Complications in Patients with Difficult Airway Using Two Techniques-Retrograde and Fibreoptic Intubation

Objective: The Aim of this study was to identify the hemodynamic response and success rate to awake retrograde endotracheal intubation (REI) and fiberoptic bronchoscope (FOB) assisted endotracheal intubation in difficult airway situation and to validate whether the REI can attenuate the hemodynamic response to tracheal intubation compared with the FOB assisted intubation. Design: Randomized Prospective Study. Methods: 64 adults, ASA I-II scheduled for elective surgery requiring endotracheal intubation were randomly allocated to either the awake REI group (n=32) or the FOB group (n=32). Non-invasive blood pressure (NIBP), heart rate (HR) and Spo2 were recorded. Time taken for intubation and success rate of intubation during the observation was also recorded. Results: During awake intubation, the magnitude of change of both NIBP and HR was greatest in Group REI as compare to Group FOB. Time taken for intubation and success rate were better in FOB group, while complication like airway trauma was higher in awake retrograde intubation group (REI). Conclusions: Awake Endotracheal intubation using FOB and REI in adult may cause increases in MAP and HR. However we observed maximum increase in heart rate and MAP occurred at the end of intubation in REI group than FOB, while time taken for intubation were lesser and success rate of intubation were superior in FOB as compare to REI group.

The Benefit of Directed Forgetting Persists After a Daytime Nap: The Role of Spindles and Rapid Eye Movement Sleep in the Consolidation of Relevant Memories.

We aimed to investigate the effect of directed forgetting instruction on memory retention after a 2-hour delay involving a daytime nap or an equivalent amount of time spent awake. We examined the associations between sleep-specific oscillations and the retention of relevant and irrelevant study materials. We applied a list-method directed forgetting paradigm manipulating the perceived relevance of previously encoded lists of words. Participants were randomly assigned to either a nap or an awake group, and to a remember or a forget subgroup. The remember and the forget subgroups were both instructed to study two consecutive lists of words, although, the forget subgroup was manipulated to forget the first list and memorize only the second one. Participants were 112 healthy individuals (44 men; Mage = 21.4 years, SD = 2.4). A significant directed forgetting effect emerged after a 2-hour delay both in the awake and sleep conditions; however, the effect was more pronounced within the sleep group. The benefit of directed forgetting, that is, relatively enhanced recall of relevant words in the forget group, was evidenced only in those participants that reached rapid eye movement (REM) phase. Non-rapid eye movement (NREM) sigma power was correlated with memory performance for the relevant (second) list, and sleep spindle amplitude was associated with the retention of both lists. These associations, however, were detected only within the forget subgroup. REM duration correlated with recall performance for the relevant (second) list within the forget subgroup, and with recall performance for the first list within the remember subgroup. A directed forgetting effect persists after a 2-hour delay spent awake or asleep. Spindle-related activity and subsequent REM sleep might selectively facilitate the processing of memories that are considered to be relevant for the future.

Microdialysis combined with UPLC–MS/MS method for determination of tetramethylpyrazine and ferulic acid in striatum of awake and anesthetic rats subjected to cerebral ischemia

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) method has been developed for the simultaneous determination and pharmacokinetic investigation of Tetramethylpyrazine (TMP) and Ferulic acid (FA) in rat striatum. The method was validated over the concentration range of 1.15–505ng/mL for TMP and 3.23–101ng/mL for FA, with a lower limit of quantitation (LLOQ) of 1.15ng/mL and 3.23ng/mL, respectively. This method can be successfully applied in pharmacokinetic studies of TMP and FA in striatum of awake and anesthetic rats. The cerebral blood flow velocity (CBF) during middle cerebral artery occlusion (MCAO) was monitored by Laser speckle contrast imaging, to observe whether the compatibility of TMP and FA could improve CBF against cerebral ischemia/reperfusion (I/R) injury. Infarct volume was examined to evaluate severity of ischemic brain injury. The pharmacokinetic study indicated that T1/2, Cmax, MRT and AUC0-inf were changed after combined administration of TMP and FA, when compared with either drug alone both in awake and anesthetic groups. The pharmacodynamics results showed that co-administration of drugs could enhance the CBF during middle cerebral artery occlusion and reduced the infarct volume. Taken together, the compatibility treatment of TMP and FA might be a promising therapeutic strategy for ischemic stroke. Further study is required to optimize the compatibility proportion.

Respiratory and hemodynamic outcomes following exchange extubation with laryngeal mask airway as compared to traditional awake extubation.

Background:Traditional awake extubation leads to respiratory complications and hemodynamic response which are detrimental in neurosurgery, ENT surgery and patients with comorbidities.Aims:The primary objective was to compare the respiratory complications and hemodynamic stress response between traditional awake extubation of a endotracheal tube (ETT) and that following exchange extubation of ETT by using a laryngeal mask airway (LMA).Settings and Design:This prospective randomized study was conducted in a Tertiary Care Centre in 60 American Society of Anesthesiologists I and II patients coming for general surgery.Materials and Methods:Patients were randomized by permuted blocks into traditional awake extubation group and exchange extubation group. At the end of surgery in traditional group, awake extubation of ETT was done. In exchange group, 0.3 mg/kg propofol was administered, and the ETT was exchanged for a LMA. Awake extubation of LMA was then performed. Respiratory complications such as bucking, coughing, desaturation and the need for airway maneuvers and hemodynamic response were noted in both groups.Analysis Tools:Chi-square test, independent sample t- and paired t-tests were used as applicable.Results:Incidence of respiratory complication was 93.3% in traditional extubation while it was only 36.7% in exchange extubation group (P < 0.001). Hemodynamic response measured immediately at extubation in terms of heart rate, systolic blood pressure (BP), diastolic BP, mean arterial pressure, and rate pressure product were all significantly lesser in exchange group when compared to traditional extubation.Conclusion:Exchange extubation with LMA decreases respiratory complications and hemodynamic stress response when compared to traditional awake extubation.

Effects of anesthetics on vesicular monoamine transporter type 2 binding to 18F-FP-(+)-DTBZ: a biodistribution study in rat brain

ObjectivesThe in vivo binding analysis of vesicular monoamine transporter type 2 (VMAT2) to radioligand has provided a means of investigating related disorders. Anesthesia is often inevitable when the investigations are performed in animals. In the present study, we tested effects of four commonly-used anesthetics: isoflurane, pentobarbital, chloral hydrate and ketamine, on in vivo VMAT2 binding to 18F-FP-(+)-DTBZ, a specific VMAT2 radioligand, in rat brain. MethodsThe transient equilibrium time window for in vivo binding of 18F-FP-(+)-DTBZ after a bolus injection was firstly determined. The brain biodistribution studies under anesthetized and awake rats were then performed at the equilibrium time. Standard uptake values (SUVs) of the interest brain regions: the striatum (ST), hippocampus (HP), cortex (CX) and cerebellum (CB) were obtained; and ratios of tissue to cerebellum were calculated. ResultsIsoflurane and pentobarbital did not alter distribution of 18F-FP-(+)-DTBZ in the brain relative to the awake group; neither SUVs nor ratios of ST/CB and HP/CB were altered significantly. Chloral hydrate significantly increased SUVs of all the brain regions, but did not significantly alter ratios of ST/CB and HP/CB. Ketamine significantly increased SUVs of the striatum, hippocampus and cortex, and insignificantly increased the SUV of the cerebellum; consequently, ketamine significantly increased ratios of ST/CB and HP/CB. ConclusionsIt is concluded that in vivo VMAT2 binding to 18F-FP-(+)-DTBZ are not altered by isoflurane and pentobarbital, but altered by chloral hydrate and ketamine. Isoflurane and pentobarbital may be promising anesthetic compounds for investigating in vivo VMAT2 binding. Further studies are warranted to investigate the interactions of anesthetics with VMAT2 binding potential with in vivo PET studies.

Extracorporeal life support in patients with refractory cardiogenic shock: keep them awake.

Traditionally, patients on extracorporeal life support (ECLS) are sedated and mechanically ventilated and therefore prone to complications related to immobility and ventilation. We adopted this 'Awake ECLS' strategy for the patients with refractory cardiogenic shock (RCS) as a bridge to decision. Sixty-eight patients with RCS were supported by ECLS (All veno-arterial) in years 2010-2014. Patients that could not survive 24 h after ECLS implantation (9 patients) were excluded from the study. Study population constituted 59 patients-'Awake' group (n = 18; maintained awake without intubation) and 'Control' group (n = 41; intubated and required mechanical ventilation). Nine (50%) patients were awake at implantation, with 5 of them remaining free of sedation and ventilator support through to explantation. Nine patients were ventilated at the time of implantation but subsequently extubated and remained non-intubated and ventilator free. Post-ECLS survival at 1 month was 78 and 42% while the survival to discharge was 78 and 37% in awake and control group, respectively. ECLS as a bridge to decision in RCS is effective in restoring adequate systemic perfusion and recovering end-organ function. ECLS can be initiated in awake patients with RCS and patients can be awakened on ECLS. The 'awake ECLS' strategy may avoid complications related to mechanical ventilation, sedation and immobilization. RCS patients supported on ECLS without severe metabolic acidosis, multiorgan failure, intra-aortic balloon pump or uncertain neurological status are more likely to be weaned from the ventilator. Patients that are awake at the time of ECLS implantation are more likely to remain awake during ECLS.

Bursting activity of substantia nigra pars reticulata neurons in mouse parkinsonism in awake and anesthetized states

Electrophysiological changes in basal ganglia neurons are hypothesized to underlie motor dysfunction in Parkinson's disease (PD). Previous results in head-restrained MPTP-treated non-human primates have suggested that increased bursting within the basal ganglia and related thalamic and cortical areas may be a hallmark of pathophysiological activity. In this study, we investigated whether there is increased bursting in substantia nigra pars reticulata (SNpr) output neurons in anesthetized and awake, head-restrained unilaterally lesioned 6-OHDA mice when compared to control mice. Confirming previous studies, we show that there are significant changes in the firing rate and pattern in SNpr neuron activity under urethane anesthesia. The regular firing pattern of control urethane-anesthetized SNpr neurons was not present in the 6-OHDA-lesioned group, as the latter neurons instead became phase locked with cortical slow wave activity (SWA). Next, we examined whether such robust electrophysiological changes between groups carried over to the awake state. SNpr neurons from both groups fired at much higher frequencies in the awake state than in the anesthetized state and surprisingly showed only modest changes between awake control and 6-OHDA groups. While there were no differences in firing rate between groups in the awake state, an increase in the coefficient of variation (CV) was observed in the 6-OHDA group. Contrary to the bursting hypothesis, this increased CV was not due to changes in bursting but was instead due to a mild increase in pausing. Together, these results suggest that differences in SNpr activity between control and 6-OHDA lesioned mice may be strongly influenced by changes in network activity during different arousal and behavioral states.

Anorectal manometry with and without ketamine for evaluation of defecation disorders in children

IntroductionAnorectal manometry (ARCM) provides valuable information in children with chronic constipation and fecal incontinence but may not be tolerated in the awake child. This study aimed to evaluate the effect of ketamine anesthesia on the assessment of anorectal function by manometry and to evaluate defecation dynamics and anal sphincter resting pressure in the context of pathophysiology of chronic functional (idiopathic) constipation and soiling in children. MethodsThis was a prospective study of children who were investigated for symptoms of chronic constipation and soiling between April 2001 and April 2004. We studied 52 consecutive children who had awake ARCM, biofeedback training and endosonography (awake group) and 64 children who had ketamine anesthesia for ARCM and endosonography (ketamine group). We age matched 31 children who had awake anorectal studies with 27 who had ketamine anesthesia. ResultsThe children in awake and ketamine groups were comparable for age, duration of bowel symptoms and duration of laxative treatments. ARCM profile was comparable between the awake and the ketamine groups with regard to anal sphincter resting pressure, rectal capacity, amplitude of rectal contractions, frequency of rectal and IAS contractions and functional length of anal canal. Of 52 children who had awake ARCM, dyssynergia of the EAS muscles was observed in 22 (42%) and median squeeze pressure was 87mm Hg (range 25–134). The anal sphincter resting pressure was non-obstructive and comparable to healthy normal children. Rectoanal inhibitory reflex was seen in all children excluding diagnosis of Hirschsprung disease. ConclusionsKetamine anesthesia does not affect quantitative or qualitative measurements of autonomic anorectal function and can be used reliably in children who will not tolerate the manometry while awake. Paradoxical contraction of the EAS can only be evaluated in the awake children and should be investigated further as the underlying cause of obstructive defecation in patients with chronic functional constipation and soiling.

Effect of anesthesia level on murine cardiac function

Background: Echocardiography allows for sensitive and non-invasive assessment of cardiac function in mice, but requires sedation and immobility, which influences cardiac performance. Minimizing the hemodynamic effects of anesthesia is extremely important for improving the applicability of animal models to the clinical setting. We sought to evaluate the effects of isoflurane dose on myocardial function in a murine model.Methods: Twelve healthy C57BL/6 mice were studied with three different isoflurane anesthesia regimens: deep anesthesia with an objective of heart rate (HR) between 350 and 400 beats per minute (bpm), light anesthesia with an objective of HR between 475 and 525 bpm and just before the mice woke up (&gt;575 bpm). Using a high-resolution ultrasound system, stroke volume, cardiac output, left ventricle dimension and fractional shortening were recorded.Results: Fractional shortening was not statistically different in the awake group and the light anesthesia group (49±5% in awake mice vs. 48±5%; p=0.62), whereas it was different compared to the deep anesthesia group (31±5%, p&lt;0.0001 compared to both groups). Similar results were found for stroke volume (41.4±5.8 ml vs. 41.6±6.9 ml; p=0.81 and 35±8.3 ml; p&lt;0.05 compared to both groups). Cardiac output was slightly lower in the light anesthesia group compared to the awake group (21.9±3.6 ml/min vs. 25.6±3.3; p=0.02) due to HR significant difference (522±17 bpm vs. 608±23 bpm; p&lt;0.0001).Conclusions: Doppler echocardiography can be performed under very light anesthesia using small doses of isoflurane without influencing cardiac inotropic function. This technique allows for accurate and reproducible assessment of cardiac function while minimizing hemodynamic perturbations.