Patient and Operational Factors Do Not Substantively Affect the Annual Departmental Quality of Anesthesiologists' Clinical Supervision and Nurse Anesthetists' Work Habits.

INTRODUCTION: Although safety climate, teamwork, and other non-technical skills in operating rooms probably influence clinical outcomes, direct associations have not been shown, at least partially due to sample size considerations. We report data from a retrospective cohort of anesthesia evaluations that can simplify the design of prospective observational studies in this area. Associations between non-technical skills in anesthesia, specifically anesthesiologists' quality of clinical supervision and nurse anesthetists' work habits, and patient and operational factors were examined. METHODS: Eight fiscal years of evaluations and surgical cases from one hospital were included. Clinical supervision by anesthesiologists was evaluated daily using a nine-item scale. Work habits of nurse anesthetists were evaluated daily using a six-item scale. The dependent variables for both groups of staff were binary, whether all items were given the maximum score or not. Associations were tested with patient and operational variables for the entire day. RESULTS: There were 40,718 evaluations of faculty anesthesiologists by trainees, 53,772 evaluations of nurse anesthetists by anesthesiologists, and 296,449 cases that raters and ratees started together. Cohen's d values were small (≤0.10) for all independent variables, suggesting a lack of any clinically meaningful association between patient and operational factors and evaluations given the maximum scores. For supervision quality, the day's count of orthopedic cases was a significant predictor of scores (P = 0.0011). However, the resulting absolute marginal change in the percentage of supervision scores equal to the maximum was only 0.8% (99% confidence interval: 0.2% to 1.4%), i.e., too small to be of clinical or managerial importance. Neurosurgical cases may have been a significant predictor of work habits (P = 0.0054). However, the resulting marginal change in the percentage of work habits scores equal to the maximum, an increase of 0.8% (99% confidence interval: 0.1% to 1.6%), which was again too small to be important. CONCLUSIONS: When evaluating the effect of assigning anesthesiologists and nurse anesthetists with different clinical performance quality on clinical outcomes, supervision quality and work habits scores may be included as independent variables without concern that their effects are confounded by association with the patient or case characteristics. Clinical supervision and work habits are measures of non-technical skills. Hence, these findings suggest that non-technical performance can be judged by observing the typical small sample size of cases. Then, associations can be tested with administrative data for a far greater number of patients because there is unlikely to be a confounding association between patient and case characteristics and the clinicians' non-technical performance.

Implementation of a hotline ("S-T-I-C-K") to expedite management of occupational bloodborne pathogen exposures at an academic medical center: A Process Improvement Initiative.

Previously, blood and body fluid exposures were managed by a visit to the University Employee Health Clinic during normal business hours and the Emergency Department after hours. We implemented the "S-T-I-C-K" program where health care personnel were evaluated immediately after exposure by a nurse-driven 24/7 hotline. Increasing accessibility to care and a simplified process for exposure management led to a significant decrease in Emergency Department utilization and time between the exposure and receipt of post-exposure prophylaxis.

Failure to breathe persists without air hunger or alarm following amygdala seizures.

Postictal apnea is thought to be a major cause of sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying postictal apnea are unknown. To understand causes of postictal apnea, we used a multimodal approach to study brain mechanisms of breathing control in 20 patients (ranging from pediatric to adult) undergoing intracranial electroencephalography for intractable epilepsy. Our results indicate that amygdala seizures can cause postictal apnea. Moreover, we identified a distinct region within the amygdala where electrical stimulation was sufficient to reproduce prolonged breathing loss persisting well beyond the end of stimulation. The persistent apnea was resistant to rising CO2 levels, and air hunger failed to occur, suggesting impaired CO2 chemosensitivity. Using es-fMRI, a potentially novel approach combining electrical stimulation with functional MRI, we found that amygdala stimulation altered blood oxygen level-dependent (BOLD) activity in the pons/medulla and ventral insula. Together, these findings suggest that seizure activity in a focal subregion of the amygdala is sufficient to suppress breathing and air hunger for prolonged periods of time in the postictal period, likely via brainstem and insula sites involved in chemosensation and interoception. They further provide insights into SUDEP, may help identify those at greatest risk, and may lead to treatments to prevent SUDEP.

Analogous cortical reorganization accompanies entry into states of reduced consciousness during anesthesia and sleep.

Theories of consciousness suggest that brain mechanisms underlying transitions into and out of unconsciousness are conserved no matter the context or precipitating conditions. We compared signatures of these mechanisms using intracranial electroencephalography in neurosurgical patients during propofol anesthesia and overnight sleep and found strikingly similar reorganization of human cortical networks. We computed the "effective dimensionality" of the normalized resting state functional connectivity matrix to quantify network complexity. Effective dimensionality decreased during stages of reduced consciousness (anesthesia unresponsiveness, N2 and N3 sleep). These changes were not region-specific, suggesting global network reorganization. When connectivity data were embedded into a low-dimensional space in which proximity represents functional similarity, we observed greater distances between brain regions during stages of reduced consciousness, and individual recording sites became closer to their nearest neighbors. These changes corresponded to decreased differentiation and functional integration and correlated with decreases in effective dimensionality. This network reorganization constitutes a neural signature of states of reduced consciousness that is common to anesthesia and sleep. These results establish a framework for understanding the neural correlates of consciousness and for practical evaluation of loss and recovery of consciousness.

Postoperative Use of the Muscle Relaxants Baclofen and/or Cyclobenzaprine Associated With an Increased Risk of Delirium Following Lumbar Fusion.

STUDY DESIGN: Retrospective, single-center, cohort study. OBJECTIVE: Investigate whether the incidence of postoperative delirium in older adults undergoing spinal fusion surgery is associated with postoperative muscle relaxant administration. SUMMARY OF BACKGROUND DATA: Baclofen and cyclobenzaprine are muscle relaxants frequently used for pain management following spine surgery. Muscle relaxants are known to cause central nervous system side effects in the outpatient setting and are relatively contraindicated in individuals at high risk for delirium. However, there are no known studies investigating their side effects in the postoperative setting. METHODS: Patients over 65 years of age who underwent elective posterior lumbar fusion for degenerative spine disease were stratified into two treatment groups based on whether postoperative muscle relaxants were administered on postoperative day one as part of a multimodal analgesia regimen. Doubly robust inverse probability weighting with cox regression for time-dependent covariates was used to examine the association between postoperative muscle relaxant use and the risk of delirium while controlling for variation in baseline characteristics. RESULTS: The incidence of delirium was 17.6% in the 250 patients who received postoperative muscle relaxants compared with 7.9% in the 280 patients who did not receive muscle relaxants ( P=0.001 ). Multivariate analysis to control for variation in baseline characteristics between treatment groups found that patients who received muscle relaxants had a 2.00 (95% CI: 1.14-3.49) times higher risk of delirium compared with controls ( P=0.015 ). CONCLUSION: Postoperative use of muscle relaxants as part of a multimodal analgesia regimen was associated with an increased risk of delirium in older adults after lumber fusion surgery. Although muscle relaxants may be beneficial in select patients, they should be used with caution in individuals at high risk for postoperative delirium.

Arousal State-Dependence of Interactions Between Short- and Long-Term Auditory Novelty Responses in Human Subjects.

In everyday life, predictable sensory stimuli are generally not ecologically informative. By contrast, novel or unexpected stimuli signal ecologically salient changes in the environment. This idea forms the basis of the predictive coding hypothesis: efficient sensory encoding minimizes neural activity associated with predictable backgrounds and emphasizes detection of changes in the environment. In real life, the brain must resolve multiple unexpected sensory events occurring over different time scales. The local/global deviant experimental paradigm examines auditory predictive coding over multiple time scales. For short-term novelty [hundreds of milliseconds; local deviance (LD)], sequences of identical sounds (/xxxxx/) are interspersed with sequences that contain deviants (/xxxxy/). Long-term novelty [several seconds; global deviance (GD)] is created using either (a) frequent /xxxxx/ and infrequent /xxxxy/ sequences, or (b) frequent /xxxxy/ and infrequent /xxxxx/ sequences. In scenario (a), there is both an LD and a GD effect (LDGD, "double surprise"). In (b), the global deviant is a local standard, i.e., sequence of identical sounds (LSGD). Cortical responses reflecting LD and GD originate in different brain areas, have a different time course, and are differentially sensitive to general anesthesia. Neural processes underlying LD and GD have been shown to interact, reflecting overlapping networks subserving the detection of novel auditory stimuli. This study examined these interactions using intracranial electroencephalography in neurosurgical patients. Subjects performed a GD target detection task before and during induction of anesthesia with propofol. Recordings were made from the auditory cortex, surrounding auditory-related and prefrontal cortex in awake, sedated, and unresponsive states. High gamma activity was used to measure the neural basis of local-by-global novelty interactions. Positive interaction was defined as a greater response to the double surprise LDGD condition compared to LSGD. Negative interaction was defined as a weaker response to LDGD. Positive interaction was more frequent than negative interaction and was primarily found in auditory cortex. Negative interaction typically occurred in prefrontal cortex and was more sensitive to general anesthesia. Temporo-parietal auditory-related areas exhibited both types of interaction. These interactions may have relevance in a clinical setting as biomarkers of conscious perception in the assessment of depth of anesthesia and disorders of consciousness.

Cortical Responses to Vowel Sequences in Awake and Anesthetized States: A Human Intracranial Electrophysiology Study.

Elucidating neural signatures of sensory processing across consciousness states is a major focus in neuroscience. Noninvasive human studies using the general anesthetic propofol reveal differential effects on auditory cortical activity, with a greater impact on nonprimary and auditory-related areas than primary auditory cortex. This study used intracranial electroencephalography to examine cortical responses to vowel sequences during induction of general anesthesia with propofol. Subjects were adult neurosurgical patients with intracranial electrodes placed to identify epileptic foci. Data were collected before electrode removal surgery. Stimuli were vowel sequences presented in a target detection task during awake, sedated, and unresponsive states. Averaged evoked potentials (AEPs) and high gamma (70-150 Hz) power were measured in auditory, auditory-related, and prefrontal cortex. In the awake state, AEPs were found throughout studied brain areas; high gamma activity was limited to canonical auditory cortex. Sedation led to a decrease in AEP magnitude. Upon LOC, there was a decrease in the superior temporal gyrus and adjacent auditory-related cortex and a further decrease in AEP magnitude in core auditory cortex, changes in the temporal structure and increased trial-to-trial variability of responses. The findings identify putative biomarkers of LOC and serve as a foundation for future investigations of altered sensory processing.

Electrocorticographic delineation of human auditory cortical fields based on effects of propofol anesthesia.

The functional organization of human auditory cortex remains incompletely characterized. While the posteromedial two thirds of Heschl's gyrus (HG) is generally considered to be part of core auditory cortex, additional subdivisions of HG remain speculative. To further delineate the hierarchical organization of human auditory cortex, we investigated regional heterogeneity in the modulation of auditory cortical responses under varying depths of anesthesia induced by propofol. Non-invasive studies have shown that propofol differentially affects auditory cortical activity, with a greater impact on non-core areas. Subjects were neurosurgical patients undergoing removal of intracranial electrodes placed to identify epileptic foci. Stimuli were 50Hz click trains, presented continuously during an awake baseline period, and subsequently, while propofol infusion was incrementally titrated to induce general anesthesia. Electrocorticographic recordings were made with depth electrodes implanted in HG and subdural grid electrodes implanted over superior temporal gyrus (STG). Depth of anesthesia was monitored using spectral entropy. Averaged evoked potentials (AEPs), frequency-following responses (FFRs) and high gamma (70-150Hz) event-related band power were used to characterize auditory cortical activity. Based on the changes in AEPs and FFRs during the induction of anesthesia, posteromedial HG could be divided into two subdivisions. In the most posteromedial aspect of the gyrus, the earliest AEP deflections were preserved and FFRs increased during induction. In contrast, the remainder of the posteromedial HG exhibited attenuation of both the AEP and the FFR. The anterolateral HG exhibited weaker activation characterized by broad, low-voltage AEPs and the absence of FFRs. Lateral STG exhibited limited activation by click trains, and FFRs there diminished during induction. Sustained high gamma activity was attenuated in the most posteromedial portion of HG, and was absent in all other regions. These differential patterns of auditory cortical activity during the induction of anesthesia may serve as useful physiological markers for field delineation. In this study, the posteromedial HG could be parcellated into at least two subdivisions. Preservation of the earliest AEP deflections and FFRs in the posteromedial HG likely reflects the persistence of feedforward synaptic activity generated by inputs from subcortical auditory pathways, including the medial geniculate nucleus.

Case Sequencing of Diagnostic Imaging Studies Performed Under General Anesthesia or Monitored Anesthesia Care During Nights and Weekends.

General anesthesia or monitored anesthesia care sometimes is provided in nonoperating room (OR) locations during nights and weekends (e.g., for magnetic resonance imaging [MRI] or computerized tomography [CT]). Rational and consistent scheduling and sequencing decisions for these diagnostic imaging procedures, including coordination with OR cases, cannot be done without knowing how long each case can wait to be started without risking a worsening of the patient's condition. We reviewed the medical records of the 81 patients who underwent diagnostic imaging procedures (78 = MRI, 3 = CT scan) under general anesthesia or monitored anesthesia care either on weekends or between 6 pm and 6 am at the University of Iowa Hospitals between March 2012 and February 2014. For 77.8% of patients, the indications could have changed clinical management within 4 hours (N = 63/81). Among the 63 imaging studies with potential immediate impact, there was documentation of results having been communicated to the treating team within 4 hours of the completion of imaging for 39 of the patients. Among the 39 patients, 15 promptly received medications or underwent procedures based on the imaging results. Thus, 15 of the 81 patients had a change in care (18.5%, 95% lower confidence limit = 11.2%). Our results are important since we showed previously that it is not possible to make rational and consistent decisions in case sequencing without knowing how long each case (including diagnostic imaging procedures) can wait to be started without a change in the patient's risk. The scheduled surgical procedure itself provides sufficient information to assess safe waiting times to start add-on cases (e.g., appendectomy). In contrast, MRI provides no context as to how potential findings will influence treatment. Our results show that the assumption cannot reasonably be made when sequencing cases that all imaging studies can or cannot wait longer than pending surgical procedures. Our results show that, for evidence-based OR management decision-making, information to decide appropriate waiting should be obtained electronically or verbally for each imaging study.

Lubeluzole and conditioned learning after cerebral ischemia.

Lubeluzole [S-4-(2-benzothiazolylmethylamino)-alpha-((3,4-difluorophenoxy)methyl)-1-piperidineethanol] reduces the severity of cerebral injury in animal models of brain ischemia. Its beneficial effects may include decreased concentration of extracellular glutamate, blockade of sodium and calcium channels, and attenuation of nitric oxide-mediated neuronal death. Previous studies have shown that global cerebral ischemia in rabbits impaired the subsequent acquisition of a trace-conditioned eyeblink reflex. Here, we examined the effect of preischemic treatment with lubeluzole on the acquisition of a trace-conditioned eyeblink response after 6.5 min of global cerebral ischemia. Three groups of rabbits underwent cerebral ischemia: one group underwent ischemia alone (I) and two groups underwent ischemia and also received lubeluzole (L(1), 1.25 mg/kg, and L(2), 2.5 mg/kg). All animals were subsequently trained using classical trace conditioning. Each training session consisted of the presentation of the conditioned stimulus (an 85-dB, 6-kHz auditory tone lasting for 100 ms) followed by a trace interval (a period of 300 ms during which no external stimulus was delivered) followed finally by the delivery of the unconditioned stimulus (a 150-ms puff of air directed at the cornea). We found that animals receiving preischemic administration of 1.25 mg/kg of lubeluzole demonstrated a significantly improved acquisition of the trace-conditioned reflex as compared to animals that did not receive lubeluzole. This finding demonstrates improved long-term neurobehavioral outcome with preischemic administration of 1.25 mg/kg of lubeluzole.