Predicting Eventual Success or Failure to Wean in Patients Receiving Long-term Mechanical Ventilation

doi:10.1378/chest.110.4.1018

Chest

Volume 110, Issue 4, October 1996, Pages 1018-1024

https://doi.org/10.1378/chest.110.4.1018 Get rights and content

Purpose

To determine if the ultimate ability of a long-term ventilated patient to wean can be predicted at the time of his or her admission to a long-term ventilator unit.

Design

Two-phased prospective study.

Setting

Long-term ventilator facility, university-affiliated.

Subjects

Adults ventilated for an average of 3 weeks, who did not have sepsis and who did not have chest tubes or progressive neurologic impairment.

Interventions

On admission to the long-term ventilator unit, historic factors, ventilator history, and the following laboratory and metabolic tests were obtained: electrolytes, serum calcium, magnesium, and phosphorus, WBC, hemoglobin, albumin, total protein, transferrin, oxygen consumption, carbon dioxide production, respiratory quotient, and dead space/tidal volume. The patients were then placed in a weaning protocol utilizing increasing duration of pressure support ventilation during the day with complete rest at night. Forty-two days after enrollment in the study, representing three times the duration of the weaning protocol, the patients who successfully weaned were compared to those who remained ventilator dependent (n=20). Patients who died or were transferred to another institution were excluded from this phase of the study, because we were trying to develop parameters that would be predictive of successful weaning. A parameter was considered to be predictive, and retained for the scoring system, if it produced at most 15% false-positives and false-negatives. A score of 0 was then assigned to the threshold value that produced no false-positives; 2 to the threshold value that produced no false-negatives and 1 to the intermediate values. The scoring system was then applied to a new prospective group of patients (n=72).

Measurements and main Results

Of all the parameters evaluated, only the following satisfied the false-positive and false-negative requirements; static compliance, airway resistance, dead space to tidal volume ratio, PaCO₂, and frequency/tidal volume. Applying these, in the scoring system, to the initial group of patients, demonstrated that a score greater than 3 was associated with failure to wean; a score less than 3 was associated with successful weaning, and a score of 3 was not predictive. Using these thresholds, the data were applied to the new prospective group of patients, which again demonstrated that a score of greater than 3 was associated with failure to wean in all cases. A score less than 3 was again associated with successful weaning but there were two false-positives. The sensitivity, specificity, and positive predictive and negative predictive values for the scoring system were 1.0, 0.91, 0.83, and 1.0, respectively. None of the individual parameters included in the scoring system demonstrated equivalent statistical results. All but two of the patients who died prior to finishing the weaning period had weaning scores, which suggested that they would not be successfully weaned.

Conclusions

Parameters that are generally available, when combined into a scoring system, can predict at the time of admission to a long-term ventilator unit, in most cases, whether a patient will eventually wean. The scoring system resulted in no false-negatives and an acceptable number of false-positives. None of the individual parameters were as reliable as the scoring system as a whole.

Section snippets

Materials and Methods

All patients who entered Vencor Hospital, Chicago, or the North Chicago VA Medical Center who had been ventilated for a minimum of 3 weeks were eligible to be studied as long as they did not exhibit signs of sepsis, which included the following: a temperature greater than 38°C or less than 35.5°C, a WBC count of greater than 12,000 mm³, or a documented source of infection. Patients with progressive neurologic impairment or expected survival of less than 2 months were also excluded. Pulmonary

Training Group of Patients

Twenty patients served as the training group for the study. Twenty-four patients were excluded based on the above criteria. None of the historic data reached the threshold limit of being present or absent 65% of the time. None of the serum chemistry values obtained were shown to be predictive, although serum albumin showed a strong trend in this direction. The parameters that met the threshold criteria were as follows: rapid shallow breathing index (RSB) measured 5 min after the beginning of a

Discussion

The purpose of this study was to develop a means of predicting the likelihood of a successful wean in patients who are admitted to a long-term ventilator unit after having received prolonged mechanical ventilation. In this way, an appropriate matching of available services to those patients who are likely to benefit from those services could be made. Because the etiologies of respiratory failure in this patient population are varied, we reasoned that a single parameter would not be predictive

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Cited by (53)

Predictive factors of weaning from mechanical ventilation and extubation outcome: A systematic review
2018, Journal of Critical Care
Citation Excerpt :
Initially, Monganroth [70] created a score composed of two tables: the first table evaluated ventilator parameters totaling 27 points, while the second table evaluated adverse factors totaling 48 points. In 1996, Gluck proposed the Gluck and Corgian Scoring System [71], composed of 5 respiratory parameters, scored from 0 to 2, with a lower score more indicative of weaning success. Yang and Tobin [60] described the respiratory compliance, respiratory rate, oxygenation, and pressure (CROP) index that is calculated by the formula [Cdyn x PImax x (PaO2/PAO2)]/f.
To identify, describe and discuss the parameters used to predict weaning from mechanical ventilation and extubation outcomes.
Systematic review of scientific articles using four electronic databases: PubMed, Embase, PEDro and Cochrane Library. Search terms included “weaning”, “extubation”, “withdrawal” and “discontinuation”, combined with “mechanical ventilation” and “predictive factors”, “predictive parameters” and “predictors for success”. In this study, we included original articles that presented predictive factors for weaning or extubation outcomes in adult patients and not restricted to a single disease. Articles not written in English were excluded.
A total of 43 articles were included, with a total of 7929 patients and 56 different parameters related to weaning and extubation outcomes. Rapid Shallow Breathing Index (RSBI) was the most common predictor, discussed in 15 studies (2159 patients), followed by Age and Maximum Inspiratory Pressure in seven studies. The other 53 parameters were found in less than six studies.
There are several parameters used to predict weaning and extubation outcomes. RSBI was the most frequently studied and seems to be an important measurement tool in deciding whether to wean/extubate a patient. Furthermore, the results demonstrated that weaning and extubation should be guided by several parameters, and not only to respiratory ones.
Respiratory Muscle Assessment in Predicting Extubation Outcome in Patients With Stroke
2012, Archivos de Bronconeumologia
Citation Excerpt :
During this process, it is not uncommon to find errors in the prediction of extubation when using regular evaluation methods to measure the ability of the patient to breathe without help, such as blood gas analysis, vital capacity (VC) determination, and minute ventilation (VE). However, airway resistance (Raw) and elasticity (static) of the respiratory system are simple, non-invasive methods that are widely used to predict the success of extubation in patients with respiratory disease.5–7 Patients with cerebral infarction, especially those who present with cerebral edema and an extensive affectation of the encephalic trunk, often present a deteriorated level of consciousness.
Patients with cerebral infarction often present impaired consciousness and unsatisfactory extubation. We aimed to assess the respiratory mechanics components that might be associated with the success of extubation in stroke patients.
Twenty consecutive patients with stroke who needed mechanical ventilation support were enrolled. The maximal inspiratory pressure, gastric and the esophageal pressure (Pdi/Pdimax), minute volume, respiratory rate, static compliance, airway resistance, rapid shallow breathing index (RSBI), inspiratory time/total respiratory cycle (Ti/Ttot), and PaO₂/FiO₂ were measured.
The group who presented success to the extubation process presented 12.5±2.2=days in mechanical ventilation and the group who failed presented 13.1±2=days. The mean Ti/Ttot and Pdi/Pdimax for the failure group were 0.4±0.08 (0.36–0.44) and 0.5±0.7 (0.43–0.56), respectively. The Ti/Ttot ratio was 0.37±0.05 (0.34–0.41; P=.0008) and the Pdi/Pdimax was 0.25±0.05 for the success group (0.21–0.28; P<.0001). A correlation was found between Pdi/Pdimax ratio and the RSBI (r=0.55; P=.009) and PaO₂/FiO₂ (r=−0.59; P=.005). Patients who presented a high RSBI (OR, 3.66; P=.004) and Pdi (OR, 7.3; P=.002), and low PaO₂/FIO₂ (OR, 4.09; P=.007), Pdi/Pdimax (OR, 4.12; P=.002) and Raw (OR, 3.0; P=.02) developed mechanical ventilation extubation failure.
Muscular fatigue index is an important predicting variable to the extubation process in prolonged mechanical ventilation of stroke patients.
Los pacientes con infarto cerebral presentan a menudo un deterioro del nivel de conciencia que hace que la extubación no sea satisfactoria. El objetivo de este estudio fue evaluar los componentes de la mecánica respiratoria que pudieran estar relacionados con el éxito de la extubación en pacientes con ictus.
Se incluyó en el estudio a 20 pacientes consecutivos con ictus que necesitaron apoyo de ventilación mecánica. Se efectuaron determinaciones de la presión inspiratoria máxima, la presión gástrica y esofágica (Pdi/Pdimáx), el volumen-minuto, la frecuencia respiratoria, la elasticidad estática, la resistencia de las vías aéreas (RAW), el índice de respiración rápida y superficial (RSRI), la relación tiempo inspiratorio/tiempo de ciclo respiratorio total (Ti/Ttot) y la PaO₂/FiO₂.
El grupo de pacientes que pudieron ser extubados con éxito tenía un tiempo de permanencia en ventilación mecánica de 12,5 ± 2,2 días, en comparación con 13,1 ± 2 días en el grupo en el que fracasó el proceso de extubación. La media Ti/Ttot y de Pdi/Pdimáx en el grupo de fracaso de la extubación fue de 0,4 ± 0,08 (0,36 a 0,44) y de 0,5 ± 0,7 (0,43 a 0,56), respectivamente. La relación Ti/Ttot fue de 0,37 ± 0,05 (0,34 a 0,41; p = 0,0008) y la relación Pdi/Pdimáx fue de 0,25 ± 0,05 en el grupo de extubación satisfactoria (0,21 a 0,28; p < 0,0001). Se observó una correlación entre la relación Pdi/Pdimáx y el RSRI (r = 0,55; p = 0,009) y la PaO₂/FiO₂ (r = −0,59; p = 0,005). Los pacientes que tenían valores altos de RSRI (OR, 3,66; p = 0,004) y Pdi (OR, 7,3; p = 0,002) o valores bajos de PaO₂/FiO₂ (OR, 4,09; p = 0,007), Pdi/Pdimáx (OR, 4,12; p = 0,002) y RAW (OR, 3,0; p = 0,02) presentaron un fracaso de la extubación de la ventilación mecánica.
El índice de fatiga muscular es una variable predictiva importante del proceso de extubación en pacientes con ictus en los que se ha utilizado una ventilación mecánica prolongada.
Value of the PaO<inf>2</inf>:FiO<inf>2</inf> ratio and Rapid Shallow Breathing Index in predicting successful extubation in hypoxemic respiratory failure
2010, Heart and Lung: Journal of Acute and Critical Care
Citation Excerpt :
This minimal difference in diagnostic accuracy between the CART model and PFR may be attributable to the limited contribution of the RSBI in this group of patients suffering from primary hypoxemic respiratory failure. Gluck et al opined that no individual parameter was as reliable as a combined-score method to predict the success or failure of weaning from mechanical ventilation in long-term mechanically ventilated patients.18 However, PFR was not used in their model, which included RSBI, PaCO2, airway resistance, static lung compliance, and dead-space-to-tidal-volume ratio.
We sought to determine the predictive value of the PaO₂:FiO₂ ratio (PFR), both independently and in combination with the standard Rapid Shallow Breathing Index (RSBI), for successful extubations in patients with primary hypoxemic respiratory failure (HRF).
A retrospective chart review of 154 patients with HRF requiring mechanical ventilation for ≥24 hours was performed. The primary outcome was reintubation within 48 hours.
142 (92%) patients were successfully extubated. Pre-extubation PFR and RSBI values among reintubated and successfully extubated patients were similar. The areas under the curve of the receiver operating characteristic curves using RSBI and PFR were .5 and .62, respectively. A PFR < 200 or RSBI ≥ 70 when the PFR was ≥200 indicated a higher risk of reintubation, with .7 sensitivity and .56 specificity (area under the curve, .69), using a classification and regression tree model.
Neither the PFR independently nor the PFR in combination with the RSBI in a classification and regression tree model accurately predicted successful extubation in patients with HRF.
Postoperative Pulmonary Management
2007, The Johns Hopkins Manual of Cardiac Surgical Care: Mobile Medicine Series
Nutrition in Oncology ICU
2022, Onco-critical Care: An Evidence-based Approach
Prediction of extubation outcome in mechanically ventilated patients: Development and validation of the Extubation Predictive Score (ExPreS)
2021, PLoS ONE

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Chest

Clinical Investigations In Critical Care: ArticlesPredicting Eventual Success or Failure to Wean in Patients Receiving Long-term Mechanical Ventilation

Purpose

Design

Setting

Subjects

Interventions

Measurements and main Results

Conclusions

Section snippets

Materials and Methods

Training Group of Patients

Discussion

Chest

Chest

Chest

Current therapy in critical care medicine

Pulmonary diseases and disorders

Statistics-difficult concepts, understandable explanations, revised Ed

Oak Park, 111: Bolchazy-Carducci

Clinical Investigations In Critical Care: Articles
Predicting Eventual Success or Failure to Wean in Patients Receiving Long-term Mechanical Ventilation