Ventilator Weaning and Terminal Extubation: Withdrawal of Life-Sustaining Therapy in Children. Secondary Analysis of the Death One Hour After Terminal Extubation Study

OBJECTIVE

Terminal extubation (TE) and terminal weaning (TW) during withdrawal of life-sustaining therapies (WLSTs) have been described and defined in adults. The recent Death One Hour After Terminal Extubation study aimed to validate a model developed to predict whether a child would die within 1 hour after discontinuation of mechanical ventilation for WLST. Although TW has not been described in children, pre-extubation weaning has been known to occur before WLST, though to what extent is unknown. In this preplanned secondary analysis, we aim to describe/define TE and pre-extubation weaning (PW) in children and compare characteristics of patients who had ventilatory support decreased before WLST with those who did not.

DESIGN

Secondary analysis of multicenter retrospective cohort study.

SETTING

Ten PICUs in the United States between 2009 and 2021.

PATIENTS

Nine hundred thirteen patients 0-21 years old who died after WLST.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

71.4% ( n = 652) had TE without decrease in ventilatory support in the 6 hours prior. TE without decrease in ventilatory support in the 6 hours prior = 71.4% ( n = 652) of our sample. Clinically relevant decrease in ventilatory support before WLST = 11% ( n = 100), and 17.6% ( n = 161) had likely incidental decrease in ventilatory support before WLST. Relevant ventilator parameters decreased were F io2 and/or ventilator set rates. There were no significant differences in any of the other evaluated patient characteristics between groups (weight, body mass index, unit type, primary diagnostic category, presence of coma, time to death after WLST, analgosedative requirements, postextubation respiratory support modality).

CONCLUSIONS

Decreasing ventilatory support before WLST with extubation in children does occur. This practice was not associated with significant differences in palliative analgosedation doses or time to death after extubation.

Narrowing the gap: expected versus deployment performance

OBJECTIVES

Successful model development requires both an accurate a priori understanding of future performance and high performance on deployment. Optimistic estimations of model performance that are unrealized in real-world clinical settings can contribute to nonuse of predictive models. This study used 2 tasks, predicting ICU mortality and Bi-Level Positive Airway Pressure failure, to quantify: (1) how well internal test performances derived from different methods of partitioning data into development and test sets estimate future deployment performance of Recurrent Neural Network models and (2) the effects of including older data in the training set on models' performance.

MATERIALS AND METHODS

The cohort consisted of patients admitted between 2010 and 2020 to the Pediatric Intensive Care Unit of a large quaternary children's hospital. 2010-2018 data were partitioned into different development and test sets to measure internal test performance. Deployable models were trained on 2010-2018 data and assessed on 2019-2020 data, which was conceptualized to represent a real-world deployment scenario. Optimism, defined as the overestimation of the deployed performance by internal test performance, was measured. Performances of deployable models were also compared with each other to quantify the effect of including older data during training.

RESULTS, DISCUSSION, AND CONCLUSION

Longitudinal partitioning methods, where models are tested on newer data than the development set, yielded the least optimism. Including older years in the training dataset did not degrade deployable model performance. Using all available data for model development fully leveraged longitudinal partitioning by measuring year-to-year performance.

Analgesia and Sedation at Terminal Extubation: A Secondary Analysis From Death One Hour After Terminal Extubation Study Data

OBJECTIVES

To describe the doses of opioids and benzodiazepines administered around the time of terminal extubation (TE) to children who died within 1 hour of TE and to identify their association with the time to death (TTD).

DESIGN

Secondary analysis of data collected for the Death One Hour After Terminal Extubation study.

SETTING

Nine U.S. hospitals.

PATIENTS

Six hundred eighty patients between 0 and 21 years who died within 1 hour after TE (2010-2021).

MEASUREMENTS AND MAIN RESULTS

Medications included total doses of opioids and benzodiazepines 24 hours before and 1 hour after TE. Correlations between drug doses and TTD in minutes were calculated, and multivariable linear regression performed to determine their association with TTD after adjusting for age, sex, last recorded oxygen saturation/F io2 ratio and Glasgow Coma Scale score, inotrope requirement in the last 24 hours, and use of muscle relaxants within 1 hour of TE. Median age of the study population was 2.1 years (interquartile range [IQR], 0.4-11.0 yr). The median TTD was 15 minutes (IQR, 8-23 min). Forty percent patients (278/680) received either opioids or benzodiazepines within 1 hour after TE, with the largest proportion receiving opioids only (23%, 159/680). Among patients who received medications, the median IV morphine equivalent within 1 hour after TE was 0.75 mg/kg/hr (IQR, 0.3-1.8 mg/kg/hr) ( n = 263), and median lorazepam equivalent was 0.22 mg/kg/hr (IQR, 0.11-0.44 mg/kg/hr) ( n = 118). The median morphine equivalent and lorazepam equivalent rates after TE were 7.5-fold and 22-fold greater than the median pre-extubation rates, respectively. No significant direct correlation was observed between either opioid or benzodiazepine doses before or after TE and TTD. After adjusting for confounding variables, regression analysis also failed to show any association between drug dose and TTD.

CONCLUSIONS

Children after TE are often prescribed opioids and benzodiazepines. For patients dying within 1 hour of TE, TTD is not associated with the dose of medication administered as part of comfort care.

Study on constant-step stress accelerated life tests in white organic light-emitting diodes

In order to obtain reliability information for a white organic light-emitting diode (OLED), two constant and one step stress tests were conducted with its working current increased. The Weibull function was applied to describe the OLED life distribution, and the maximum likelihood estimation (MLE) and its iterative flow chart were used to calculate shape and scale parameters. Furthermore, the accelerated life equation was determined using the least squares method, a Kolmogorov-Smirnov test was performed to assess if the white OLED life follows a Weibull distribution, and self-developed software was used to predict the average and the median lifetimes of the OLED. The numerical results indicate that white OLED life conforms to a Weibull distribution, and that the accelerated life equation completely satisfies the inverse power law. The estimated life of a white OLED may provide significant guidelines for its manufacturers and customers.

[Effect and mechanism of active fraction A guizhi decoction on dual-directional thermoregulation: effect on heat shock protein in hypothalamus of rats]

OBJECTIVE

To investigate the effect of active fraction A in Guizhi Decoction (Fr.A) on dual-directional thermoregulation and its mechanism of influencing heat shock protein (HSP) in hypothalamus.

METHOD

Using Western blot method to measure HSP of hypothalamus in febrile and hypothermal rats.

RESULTS

Regulating the body temperature in dual-direction, Fr.A could antagonize the decrease of HSP contents of hypothalamus in hypothermal rats induced by aminopyrine, and abate the HSP content in febrile rats induced by yeast.

CONCLUSION

Fr.A adjusts the body temperature through regulating the contents of HSP of hypothalamus in febrile and hypothermal rats.

[Preliminary analysis of relationship between immunological changes and syndrome differentiation-typing in traditional Chinese medicine and prognosis with chronic idiopathic thrombocytopenic purpura]

In order to study the relationship between the basement immunological changes, TCM Syndrome Differentiation and prognosis, alkaline phosphates antialkaline phosphatase (APAAP) and ELISA assay were used to determine the T lymphocyte subsets, the platelet associated antibody (PAIgG, PAIgA, PAIgM) and plasma antiplatelet-autoantibodies (GP II b, GP III a, GP I b) in 55 chronic idiopathic thrombocytopenic purpura (ITP) and 53 healthy subjects as control. The results indicated that the immunological changes was closely related to the prognosis, while the TCM Syndrome Differentiation was also related to it, which denoted that it is significant to investigate both factors in guiding treatment and assessing the prognosis.

[Mechanism of decoction of guizhi tang on dual-directional thermoregulation. Effect on the action of bombesin]

Hypothermia induced by administration of bombesin into the lateral ventricle of brain in cold exposed rats could be inhibited by Guizhi Tang (GZT). The GZT could also reverse the potency of fever induced by injection of [D-Phe12] bombesin, a bombesin receptor antagonist, into the brain of febrile rats. But there was no effect of GZT on body temperature when bombesin and [D-Phe12] bombesin were simultaneously injected into the lateral ventricle of cold exposed rats. These studies indicated that the dual-directional thermoregulation of GZT was carried out partially by affecting the bombesin receptor in thermoregulation center of hypothalamus.

[Mechanism of guizhi tang on dual-directional thermoregulation--effect of prostaglandin E2 level in hypothalamus of rats]

Antipyretic action was found in febrile rats induced by yeast, and body temperature was elevated in hypothermia rats induced by aminopyrine, when 10 g/kg of Guizhi Tang (GZT) was administered per os. The content of prostaglandin E in the hypothalamus of rats was determined with the radioimmunoassay. Administration of GZT in 10 g/kg p.o. could both decrease the PGE2 level of hypothalamic blood in febrile rats, and increase the PGE2 level in hypothermia rats. Antipyretic action of GZT was also displayed when microinjection of PGE2 into the lateral ventricle which produced fever in rats. The evidence was provided that GZT might carry out at least part of the dual-directional regulating action in body temperature through the promotion or inhibition on PGE2 synthesis, release, or metabolism in the thermoregulatory center.