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Tag Archives: weaning

Canadian Neighbor Pharmacy: Prolonged Intubation Rates After Coronary Artery Bypass Surgery and ICU Risk Stratification Score

Coronary artery bypass graftHength of stay in the ICU following coronary artery bypass graft (CABG) surgery has been substantially shortened during the past decade, thus reflecting the current trend for what is called fast-track cardiac anesthesia (FTCA). The efforts of physicians to ensure early extubation of patients are supporting this policy in most ICUs, and a vast majority of patients are successfully extubated within 6 to 8 h after the procedure. However, despite this aim, a large number of patients requiring mechanical ventilation still remain in the ICU for > 24 or 48 h, The appropriate identification of these patients could be of interest for planning ICU resources when the patient enters the unit.

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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Recommendation

Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: RecommendationWe believe that an index of increased airway resistance related to respiratory muscle capability may be a sensitive and specific predictor of outcome of weaning in patients with COPD. It has suggested by other authors that a rapid shallow breathing index (f/VT) would have high predictive value. Although this may be the case in reduced pulmonary compliance, it cannot be supported by our data for patients with COPD.
In summary, this study describes 21 patients who were successfully and appropriately weaned by an ALV controller as well as 4 patients who were identified as not weanable by the ALV controller and appropriately supported. Only one patient could be considered to have possibly been inappropriately weaned by the ALV controller down to a pressure support level of 5 cm H2O, because he became tac-hypneic on the T-piece some hours after the wean and required further ventilation. natural asthma inhaler

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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Conclusion

Our study suggests that it might be appropriate to set V’gA to 100% of the patients’ needs until they are ready for the final weaning attempt, at which time the target value of 33% of the measured value is introduced. In fact, the IPD, P0.1, and PE values are higher in the successfully weaned patients than in the failed-to-wean patients which indicates that the former already did an increased amount of work of breathing despite the high respiratory support given to them at baseline. However, further work is necessary to clarify the strategy of V’gA setting.
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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Comment

Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: CommentSince ALV uses closed loop control, an increase in Vt will result in a decrease of pressure support. Furthermore, ALV will increase or decrease respiratory support in an attempt to guide the patient into a breathing pattern that theoretically requires the least amount of work. This requires a model of work of breathing. The model used in ALV is based on the work of Otis et al and Mead and calls for the measurement of the respiratory time constant. Another pertinent input to the model is a measure of dead space incorporating patient size (lung size) rather than patient abnormality. Therefore, series dead space was chosen for the ALV controller algorithm and not, as originally proposed by Otis et al, total respiratory dead space. comments

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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Discussion

The art of weaning patients who have been in respiratory failure is to wean them in a timely manner without risk and to ensure that they remain successfully weaned. Various techniques of weaning are described that serially measure respiratory parameters and reduce ventilatory support in a controlled manner to ensure a safe and successful wean.” These currently used techniques are time and labor intensive. The weaning criteria and methods used have to be modified depending on each patient’s underlying disease process and ability to overcome a reduced compliance and/or an increased airway resistance. Unless close attention is paid to the patient during the weaning process, the patient could be stressed by the procedure and placed at risk. Recent developments in ventilator and computer technology have made closed loop control of ventilation feasible, and have the potential to make ventilation and weaning more comfortable and safer. Although computers have recently been used to improve the task, the implemented protocols adhere to the conventional clinical approach: weaning is considered to be a task that can be done by the machine and the patient will follow if he is weanable. review

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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Analysis

Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: AnalysisThis patient was excluded from further analysis. In the COPD group, six patients were successfully weaned whereas in three patients, the ALV controller maintained pressure support respiration and these were documented as having failed the wean. However, apart from the patient in the pulmonary parenchymal group who was unable to be assessed, the patients in the three groups who failed the weans at the time of this study were subsequently weaned from ventilatory support and recovered from their acute disease that had caused the respiratory failure. Table 3 shows a comparison between the successful and failed wean cases at baseline. The differences seen in Pawmax, Rtot, P0.1, IPD, PE, and VdS were not statistically significant. Table 4 and Figure 3 show that the ALV controller reduced the APinsp to 5 cm H2O in the successfully weaned patients but maintained an elevated pressure support level in all but one patient who failed to wean. generic yaz

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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Results

In addition to these parameters, we also measured an index of rapid shallow breathing (RSB=f/VT)n and the level of pressure support (APinsp) subsequent to placing the patients on the ALV controller. The 27 patients studied ranged in age from 20 to 74 years (mean, 44 years) and had been ventilated in our RICU for respiratory failure for 1 to 30 days (mean, 7.7 days). We included nine patients with normal lungs (mean Apache II score on admission: 13.2), nine patients with parenchymal lung disease (mean Apache II score on admission: 14.6) and nine patients with severe chronic obstructive lung disease (mean Apache II score on admission: 18.7). Patient data and primary diagnoses are given in Table 1.
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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Treatment

Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: TreatmentAdaptive lung ventilation was implemented on a modified computer-controllable ventilator (Hamilton Amadeus), a PC-based lung function analyzer, and a computer (Macintosh SE). Airway flow, airway pressure, and instantaneous C02 concentration were measured between the Y-piece and endotracheal tube. For this purpose, a variable orifice pneumotachograph (Hamilton) and a C02 analyzer (Novametrix 1260) were used. All signals were low-pass filtered with a second order bessel filter having a 3-dB cutoff frequency of 25 Hz. The filtered signals were read into a compatible microcomputer (IBM-PC/AT) at a sampling rate of 60 Hz using an AD converter DT2801 (Data Translation, Marlboro, Mass). The signals were corrected for gas viscosity changes and C02 analyzer delay. An algorithm based on the C02 and flow signals detected the start of inspiration and expiration. This allowed for automatic calculation of breath-by-breath lung function indices. Inspiratory time (Ti) expiratory time (Те), and total respiratory rate (f) were measured. Integration of the flow signal yielded the inspired volume (Vi) and the expired volume (Ve). asthma inhaler

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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Data

Three groups of patients were studied: group 1—normal lungs; group 2—pulmonary parenchymal abnormality; and group 3—chronic obstructive pulmonary disease (Table 1). The patients were initially ventilated for at least 30 min using the same mode and settings on which each patient had been ventilated during the mechanical ventilatory period. In this baseline condition, gross alveolar ventilation (V’gA in liters per minute) was measured as respiratory rate (f) times tidal volume (Vt) minus series dead space ventilation (f°VT—f’VdS) at baseline. The ventilator was then switched to ALV with a target V’gA identical to the baseline condition.

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Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: Methods

Automatic Weaning From Mechanical Ventilation Using an Adaptive Lung Ventilation Controller: MethodsAt the same time, the Vt will be watched by the second closed loop controller. Again, for paralyzed patients, the inspiratory pressure level is increased until the target Vt is achieved. As soon as the patient develops significant breathing activity, the Vt, at a given inspiratory pressure level, starts to rise. In response to this rise, the tidal volume controller reduces pressure support to maintain the target Vt, thereby weaning the patient from pressure support. If the patient becomes tachypneic, Vt usually drops and the tidal volume controller responds to this by increasing the pressure support level that increases Vt and decreases the respiratory rate. Thus, appropriate control of the volume will control also the respiratory rate. Here

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