Utilizing Forced Vital Capacity to Predict Low Lung Compliance and Select Intraoperative Tidal Volume During Thoracic Surgery.

BACKGROUND: Tidal volume selection during mechanical ventilation utilizes dogmatic formulas that only consider a patient's predicted body weight (PBW). In this study, we investigate whether forced vital capacity (FVC) (1) correlates better to total lung capacity (TLC) than PBW, (2) predicts low pulmonary compliance, and (3) provides an alternative method for tidal volume selection. METHODS: One hundred thirty thoracic surgery patients had their preoperative TLC calculated via 2 methods: (1) pulmonary function test (PFT; TLCPFT) and (2) computed tomography 3D reconstruction (TLCCT). We compared the correlation between TLC and PBW with the correlation between TLC and FVC to determine which was stronger. Dynamic pulmonary compliance was then calculated from intraoperative ventilator data and logistic regression models constructed to determine which clinical measure best predicted low compliance. Ratios of tidal volume/FVC plotted against peak inspiratory pressure were utilized to construct a new model for tidal volume selection. Calculated tidal volumes generated by this model were then compared with those generated by the standard lung-protective formula Vt = 7 cc/kg. RESULTS: The correlation between FVC and TLC (0.82 for TLCPFT and 0.76 for TLCCT) was stronger than the correlation between PBW and TLC (0.65 for TLCPFT and 0.58 for TLCCT). Patients with very low compliance had significantly smaller lung volumes (forced expiratory volume at 1 second, FVC, TLC) and lower diffusion capacity of the lungs for carbon monoxide when compared with patients with normal compliance. An FVC cutoff of 3470 cc was 100% sensitive and 51% specific for predicting low compliance. The proposed equation Vt = FVC/8 significantly reduced calculated tidal volume by a mean of 22.5% in patients with low pulmonary compliance without affecting the mean tidal volume in patients with normal compliance (mean difference 0.9%). CONCLUSIONS: FVC is more strongly correlated to TLC than PBW and a cutoff of about 3.5 L can be utilized to predict low pulmonary compliance. The equation Vt = FVC/8 reduced mean calculated tidal volume in patients with low pulmonary compliance and/or small lungs.

Effect of Performance Deficiencies on Graduation and Board Certification Rates: A 10-yr Multicenter Study of Anesthesiology Residents.

BACKGROUND: This multicenter, retrospective study was conducted to determine how resident performance deficiencies affect graduation and board certification. METHODS: Primary documents pertaining to resident performance were examined over a 10-yr period at four academic anesthesiology residencies. Residents entering training between 2000 and 2009 were included, with follow-up through February 2016. Residents receiving actions by the programs' Clinical Competency Committee were categorized by the area of deficiency and compared to peers without deficiencies. RESULTS: A total of 865 residents were studied (range: 127 to 275 per program). Of these, 215 residents received a total of 405 actions from their respective Clinical Competency Committee. Among those who received an action compared to those who did not, the proportion graduating differed (93 vs. 99%, respectively, P < 0.001), as did the proportion achieving board certification (89 vs. 99%, respectively, P < 0.001). When a single deficiency in an Essential Attribute (e.g., ethical, honest, respectful behavior; absence of impairment) was identified, the proportion graduating dropped to 55%. When more than three Accreditation Council for Graduate Medical Education Core Competencies were deficient, the proportion graduating also dropped significantly. CONCLUSIONS: Overall graduation and board certification rates were consistently high in residents with no, or isolated, deficiencies. Residents deficient in an Essential Attribute, or multiple competencies, are at high risk of not graduating or achieving board certification. More research is needed on the effectiveness and selective deployment of remediation efforts, particularly for high-risk groups.

Evaluating the performance of low cost chemical sensors for air pollution research.

Low cost pollution sensors have been widely publicized, in principle offering increased information on the distribution of air pollution and a democratization of air quality measurements to amateur users. We report a laboratory study of commonly-used electrochemical sensors and quantify a number of cross-interferences with other atmospheric chemicals, some of which become significant at typical suburban air pollution concentrations. We highlight that artefact signals from co-sampled pollutants such as CO2 can be greater than the electrochemical sensor signal generated by the measurand. We subsequently tested in ambient air, over a period of three weeks, twenty identical commercial sensor packages alongside standard measurements and report on the degree of agreement between references and sensors. We then explore potential experimental approaches to improve sensor performance, enhancing outputs from qualitative to quantitative, focusing on low cost VOC photoionization sensors. Careful signal handling, for example, was seen to improve limits of detection by one order of magnitude. The quantity, magnitude and complexity of analytical interferences that must be characterised to convert a signal into a quantitative observation, with known uncertainties, make standard individual parameter regression inappropriate. We show that one potential solution to this problem is the application of supervised machine learning approaches such as boosted regression trees and Gaussian processes emulation.

A Comparison of the Haider Tube-Guard® Endotracheal Tube Holder Versus Adhesive Tape to Determine if This Novel Device Can Reduce Endotracheal Tube Movement and Prevent Unplanned Extubation.

BACKGROUND: Endotracheal tube security is a critical safety issue. We compared the mobility of an in situ endotracheal tube secured with adhesive tape to the one secured with a new commercially available purpose-designed endotracheal tube-holder device (Haider Tube-Guard). We also observed for the incidence of oropharyngeal or facial trauma associated with the 2 tube fixation methods. METHODS: Thirty adult patients undergoing general anesthesia with neuromuscular blockade were prospectively enrolled. Immediately after intubation, a single study author positioned the endotracheal tube tip in the distal trachea using a bronchoscope. Anesthesiologists caring for patients secured the tube in their normal fashion (always with adhesive tape). A force transducer was used to apply linear force, increasing to 15 N or until the principal investigator deemed that the force be aborted for safety reasons. The displacement of the endotracheal tube was measured with the bronchoscope. Any tape was then removed and the endotracheal tube secured with the Haider Tube-Guard device. The linear force was reapplied and the displacement of the endotracheal tube measured. The Haider Tube-Guard device was left in place for the duration of the case. The patient's face and oropharynx were examined for any evidence of trauma during surgery and in the recovery room. On discharge from the postanesthesia care unit, the patient answered a brief survey assessing for any subjective evidence of minor facial or oropharyngeal trauma. RESULTS: Under standardized tension, the endotracheal tube withdrew a mean distance of 3.4 cm when secured with adhesive tape versus 0.3 cm when secured with the Haider Tube-Guard (P <0.001). Ninety-seven percent of patients (29/30) experienced clinically significant endotracheal tube movement (>1 cm) when adhesive tape was used to secure the tube versus 3% (1/30) when the Haider Tube-Guard was used (P <0.001). Thirty percent of patients (9/30) were potentially deemed a high extubation risk (endotracheal tube movement >4 cm) when the endotracheal tube was secured with tape versus 0% (0/30) when secured with the Haider Tube-Guard (P = 0.004). Six patients with taped endotracheal tubes required the traction to be aborted before 15 N of force was achieved to prevent potential extubation as the tape either separated from the face or stretched to allow excessive endotracheal tube movement. None of the patients appeared to sustain any injury from the Haider Tube-Guard device. CONCLUSIONS: The Haider Tube-Guard significantly reduced the mobility of the endotracheal tube when compared with adhesive tape and was well tolerated in our observations.

An open label trial of donepezil for enhancement of rapid eye movement sleep in young children with autism spectrum disorders.

BACKGROUND: Rapid eye movement (REM) sleep is greatest in the developing brain, is driven by acetylcholine, and may represent a protected time for neuroplasticity. Recently published data from our lab observed that children with autism spent significantly less time in this state during a single night recording than did typically developing children and those with developmental delay without autism. The objective of this study was to determine whether or not donepezil can increase the REM % in children with diagnosed autism spectrum disorder (ASD) found to have REM % values of at least two standard deviations below expected for age. METHODS: Five subjects found to have an ASD (ages 2.5-6.9 years) and demonstrated deficits in REM sleep compared with within-lab controls were enrolled in a dose finding study of donepezil. Each subject was examined by polysomnography for REM sleep augmentation after drug administration. RESULTS: REM sleep as a percentage of Total Sleep Time was increased significantly and REM latency was decreased significantly after drug administration in all subjects. No other observed sleep parameter was changed significantly. CONCLUSIONS: Donepezil can increase the amount of time that children with an ASD spend in the REM sleep state. A double-blind, placebo-controlled trial is needed to assess the association between REM sleep augmentation and learning, cognition, and behavior in such children.

Rapid eye movement sleep percentage in children with autism compared with children with developmental delay and typical development.

OBJECTIVE: To compare objective polysomnographic parameters between 3 cohorts: children with autism, typical development, and developmental delay without autism. DESIGN: Overnight polysomnographic recordings were scored for sleep architecture according to American Academy of Sleep Medicine criteria by a board-certified sleep medicine specialist blind to diagnosis for studies collected between July 2006 and September 2009. SETTING: Subjects were evaluated in the pediatric ward in the Clinical Research Center of the National Institutes of Health. PARTICIPANTS: First 60 consecutive children with autism, 15 with typical development, and 13 with developmental delay matched for nonverbal IQ to the autism group, ranging in age from 2 to 13 years, selected without regard to the presence or absence of sleep problem behavior. MAIN OUTCOME MEASURES: Total sleep time, latencies to non-rapid eye movement (REM) and REM sleep, and percentages of total sleep time for stages 1 and 2 sleep, slow-wave sleep, and REM sleep. RESULTS: There were no differences between the typical vs developmental delay groups. Comparison of children with autism vs typical children revealed shorter total sleep time (P = .004), greater slow-wave sleep percentage (P = .001), and much smaller REM sleep percentage (14.5% vs 22.6%; P < .001). Comparison of children with autism vs children with developmental delay revealed shorter total sleep time (P = .001), greater stage 1 sleep percentage (P < .001), greater slow-wave sleep percentage (P < .001), and much less REM sleep percentage (14.5% v 25%; P < .001). CONCLUSION: A relative deficiency of REM sleep may indicate an abnormality in neural organization in young children with autism that is not directly associated with or related to inherent intellectual disability but may serve as a window into understanding core neurotransmitter abnormalities unique to this disorder.

Performance improvement in the era of quality improvement.

A discussion among industry leaders on improving performance in the era of quality improvement.