Background: The literature suggests there is variability in the clinical practice of spontaneous breathing trials (SBTs). Evidence-based literature and clinical practice guidelines (CPGs) have been published over time to address various aspects of SBT implementation. It can take many years for evidence-based recommendations to be adopted into clinical practice. The American Association for Respiratory Care recently published a CPG addressing 4 aspects of SBT implementation. Methods: This study evaluated how the clinical practice of SBTs compares to the recommendations of the CPG. An online survey was developed to assess how hospitals with SBT protocols perform different components of SBTs. Descriptive statistics were used in the data analysis. Results: A total of 26 representatives from different health care institutions in the United States met the criteria for data analysis; 61.5% of reported protocols use rapid shallow breathing index, which is not in alignment with the current recommendation; 77% reported the use of pressure support (PS); 11.5% specified the use of a T-piece, and 11% specified the option of either PS or T-piece during the SBT. The responses were 100% in alignment with the current recommendation of performing a SBT with or without support; 73.1% aligned with having a standardized approach to performing SBTs by specifying when the SBT will be initiated; 65.4% perform an SBT during the day, though it was not specified if it occurs before noon each day; 53.8% allow for an increase in FIO2 during an SBT, which is not in alignment with the current recommendations. Conclusions: The reported hospitals' protocols demonstrated moderate alignment with the 4 CPG recommendations. Identifying current discrepancies between clinical practice and CPGs will allow for the assessment of the adoption of recommendations into clinical practice over time. Further assessment could be performed to determine if there is an impact on patient outcomes.

Despite prior publications of clinical practice guidelines related to ventilator liberation, some questions remain unanswered. Many of these questions relate to the details of bedside implementation. We, therefore, formed a guidelines committee of individuals with experience and knowledge of ventilator liberation as well as a medical librarian. Using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology, we make the following recommendations: (1) We suggest that calculation of a rapid shallow breathing index is not needed to determine readiness for a spontaneous breathing trial (SBT) (conditional recommendation; moderate certainty); (2) We suggest that SBTs can be conducted with or without pressure support ventilation (conditional recommendation, moderate certainty); (3) We suggest a standardized approach to assessment and, if appropriate, completion of an SBT before noon each day (conditional recommendation, very low certainty); and (4) We suggest that FIO2 should not be increased during an SBT (conditional recommendation, very low certainty). These recommendations are intended to assist bedside clinicians to liberate adult critically ill patients more rapidly from mechanical ventilation.

The expression of rat brain voltage-sensitive Na+ channel mRNAs in Schwann cells was examined using in situ hybridization cytochemistry and RT-PCR. The mRNAs of rat brain Na+ channel subtype II and III, but not subtype I, were detected in cultured Schwann cells from sciatic nerve and in intact sciatic nerve, which contains Schwann cells but not neuronal cell bodies. These results indicate that rat brain Na+ channel mRNAs, which have been considered as mainly neuronal-type messages, are also expressed in glial cells in vitro and in vivo.

BACKGROUND: The COVID-19 pandemic has led to an increased demand for mechanical ventilators and concerns of a ventilator shortage. Several groups have advocated for 1 ventilator to ventilate 2 or more patients in the event of such a shortage. However, differences in patient lung mechanics could make sharing a ventilator detrimental to both patients. Our previous study indicated failure to ventilate in 67% of simulations. The safety problems that must be solved include individual control of tidal volume (V-T), individual measurement of V-T, individualization of PEEP settings, and individual PEEP measurement. The purpose of this study was to evaluate potential solutions developed at our institution. METHODS: Two separate lung simulators were ventilated with a modified multiplex circuit using pressure control ventilation. Parameters of the lung models used for simulations (resistance and compliance) were evidence-based from published studies. Individual circuit-modification devices were first evaluated for accuracy. Devices were an adjustable flow diverter valve, a prototype dual volume display, a PEEP valve, and a disposable PEEP display. Then the full modified multiplex circuit was assessed by ventilating 6 pairs of simulated patients with different lung models and attempting to equalize ventilation. Ventilation was considered equalized when V-T and end-expiratory lung volume were within 10% for each simulation. RESULTS: The adjustable flow diverter valve allowed volume adjustment to 1 patient without affecting the other. The average error of the dual volume display was -17%. The PEEP valves individualized PEEP, but the PEEP gauge error ranged from 17% to 41%. Using the multiplex circuit, ventilation was equalized regardless of differences in resistance or compliance, reversing the "failure modes" of our previous study. CONCLUSIONS: The results of this simulation-based study indicate that devices for individual control and display of VT and PEEP are effective in extending the usability and potential patient safety of multiplex ventilation.