Factors associated with extubation failure in the intensive care unit patients after spontaneous breathing trial

Niraj Kumar Keyal; Roshana Amatya; Gentle Sunder Shrestha; Saurabh Pradhan; Krishna Kumar Agrawal; Hem Raj Paneru

doi:10.4103/cjhr.cjhr_39_19

ORIGINAL ARTICLE

Year : 2020 | Volume : 7 | Issue : 3 | Page : 230-234

Factors associated with extubation failure in the intensive care unit patients after spontaneous breathing trial

Niraj Kumar Keyal¹, Roshana Amatya², Gentle Sunder Shrestha², Saurabh Pradhan², Krishna Kumar Agrawal³, Hem Raj Paneru²
¹ Department of Critical Care Medicine, B and C Medical College and Teaching Hospital and Research Centre, Birtamod, Jhapa, Nepal
² Department of Anaesthesiology, Institute Medicine, Kathmandu, Nepal
³ Department of Nephrology, Nepal Medical College, Kathmandu, Nepal

Date of Submission	31-Mar-2019
Date of Decision	01-Sep-2019
Date of Acceptance	22-Nov-2019
Date of Web Publication	25-Jan-2021

Correspondence Address:
Niraj Kumar Keyal
B and C Medical College and Teaching Hospital and Research Centre, Birtamode, Jhapa
Nepal

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/cjhr.cjhr_39_19

Abstract

Introduction: Extubation failure is associated with high mortality and poor outcome of patients. Aims: This study was conducted to assess the factors associated with extubation failure in the intensive care unit (ICU) patients planned for extubation. Settings and Design: It was a prospective observation study conducted in all patients aged >18 years admitted in the ICU of a tertiary care hospital. Subjects and Methods: It was done on 108 patients who were planned for extubation. Patients were assessed by an intensivist clinically and decided whether a patient can be extubated on clinical grounds. Spontaneous breathing trial (SBT) was done for 2 h by T-piece in patients who met clinical and objective criteria. Arterial blood gas (ABG) was done in all patients who successfully completed SBT. Patients with successful SBT and acceptable ABG were extubated. Patients were observed for 48 h for extubation failure, and the reason for reintubation was recorded. Statistical Analysis Used: Independent Student's t-test and Chi-square test were used for data analysis. Results: Of 108 patients who passed the SBT, 96 (88.88%) patients had acceptable ABG and were extubated. 85 (88%) underwent successful extubation and 11 (12%) underwent unsuccessful extubation. Duration of mechanical ventilation (MV) and chronic obstructive airway disease was a risk factor associated with extubation failure. Conclusion: Duration of MV of >2 days and chronic obstructive pulmonary disease were identified as independent risk factors for extubation failure.

Keywords: Chronic obstructive airway disease, extubation, spontaneous breathing trial

How to cite this article:
Keyal NK, Amatya R, Shrestha GS, Pradhan S, Agrawal KK, Paneru HR. Factors associated with extubation failure in the intensive care unit patients after spontaneous breathing trial. CHRISMED J Health Res 2020;7:230-4

How to cite this URL:
Keyal NK, Amatya R, Shrestha GS, Pradhan S, Agrawal KK, Paneru HR. Factors associated with extubation failure in the intensive care unit patients after spontaneous breathing trial. CHRISMED J Health Res [serial online] 2020 [cited 2021 Feb 26];7:230-4. Available from: https://www.cjhr.org/text.asp?2020/7/3/230/307821

Introduction

Mechanical ventilation (MV) is life-saving. Patients spent 40% of time in weaning, and prolonged intubation is associated with ventilator-associated pneumonia, barotrauma, increased length of stay, cost, and death.^[1] Extubation failure is defined as reintubation within 48 h^[2] of extubation and occurs in about 24.5% of patients.^[3],[4] It is associated with prolonged stay, tracheostomy, and higher mortality.^[5],[6],[7]

Due to limited resources, high mortality in the intensive care unit (ICU), and high economic burden on the patient due to lack of health insurance, this study was conducted in Nepal to identify risk factors for extubation failure that may decrease mortality and financial burden and improve outcome of ICU patients.

Subjects and Methods

Design

We conducted a prospective observational study in an eleven 11-bedded tertiary-level mix surgical medical ICU of tertiary-level hospital for 1 year. Ethical approval from the institutional review board was obtained before enrollment of patients in this study. Written informed consent was obtained from a surrogate decision-maker of the patient.

Inclusion and exclusion criteria

All patients aged >18 years admitted in the ICU of tertiary-level hospitals who underwent invasive MV and were planned to undergo extubation were included in this study. Patients whose surrogate decision-maker did not give written informed consent were excluded from this study.

Study procedures

Ventilator management was done as per the protocol of ICU and decision of the treating physician. Intensivist thoroughly assessed the patient clinically and decided whether a patient could be extubated on clinical grounds. We collected the following data from each patient age, sex, sequential organ failure assessment (SOFA) score, reason for intubation, number of days on MV, mode of MV, and hemoglobin on the day of planned extubation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), respiratory frequency, and oxygen saturation as measured by oximetry (SpO₂), while on the ventilator and during the spontaneous breathing trial (SBT) by T-piece , pH, partial pressure of oxygen (PaO₂), partial pressure of carbon dioxide (PaCO₂), and partial pressure of oxygen/fraction of inspired oxygen ratio (PaO₂ /FiO₂) values on full ventilatory support and after the SBT by T-piece.

The decision to start SBT by T-piece for 2 h was made by the intensivist once the patient meets all of the following clinical and objective criteria as (i) clinical assessment: (a) presence of cough reflex on tracheal suctioning and (b) absence of excessive secretion; (ii) objective measurement: (a) MAP >65 mmHg with no or low-dose vasopressors such as dopamine or dobutamine 5 mcg/kg/min or nor adrenaline 0.05 mcg/kg/min, (b) Glasgow Coma Scale (GCS) >8 (verbal component is excluded in intubated patient) eye and motor component will be only included, (c) no fever (temperature <38°C), (d) HR <140/min, (e) spontaneous tidal volume (V_T) >5 ml/kg, (f) spontaneous frequency (f) <35/min, (g) f/V_T <105, (h) minute ventilation <10 l, (i) SpO₂ >90 on FiO₂ <0.4.

Rapid shallow breathing index (RSBI) was calculated by setting positive end-expiratory pressure (PEEP) =0 and pressure support ventilation = 0 cmH₂O for 1 min. V_T and respiratory rate (RR) were displayed on ventilator. RSBI was calculated as the ratio of V_T and RR.

During SBT, if patient manifests any one of the following sign for 2 min, then it was considered as SBT failure: (a) SaO₂ <90 on FiO₂ >50%, (b) f >35/min or increase by >50% from baseline of SBT, (c) HR >140/min or increase by >20% from baseline of SBT, (d) SBP >180 mmHg or increase by >20% from baseline of SBT, (e) SBP <90 mmHg, (f) presence of cardiac arrhythmias, (g) cyanosis, and (h) diaphoresis. After successful completion of SBT, arterial blood gas (ABG) was done.

Patient was extubated who had met the acceptable ABG criteria as follows: (a) pH = 7.35–7.45, (b) PaCO₂ <50 mmHg, (c) PaO₂ without PEEP > 60 mmHg, and (d) PaO₂/FiO₂ >150.

Patients with successful SBT but unacceptable ABG were not extubated and were managed according to intensivist on-duty. The patient was observed for 48 h for extubation failure.

Patients were observed for 48 h for extubation failure. Moreover, the reason for extubation failure was recorded.

Statistical analysis

Data collection was done in a preformed sheet. Values are presented as mean (±standard deviation) or frequency. Independent Student's t-test was used to compare mean values of hemodynamic, respiratory, and ABG variables between extubation success and failure patients. Difference between extubation success and failure patients was analyzed using Chi-square test. For all determination, P < 0.05 was considered statistically significant.

Results

A total of 108 patients were included in this study.

[Table 1] shows demographic characteristics of the study population. The mean age was 45.85 ± 19.63 years, 56 (51.9%) were female, and 52 (48.1%) were male.

Table 1: Demographic characteristics of the study population

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[Table 2] shows clinical characteristics of the study population. Most of the patients in the study had neurological disease and high SOFA score at time of admission in the ICU. Hypertension (HTN) was the most common comorbidity in our study population. The most common reason for intubation was prophylactic ventilatory support followed by hypoxemia and acute respiratory failure. Of 108 patients included, 43 (39.8%) had Mechanical Ventilation (MV) ≤2 days and 65 (60.2%) had MV >2 days.

Table 2: Clinical characteristics of the population

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[Table 3] shows that of 108 patients who passed the SBT, 96 (88.88%) patients had acceptable ABG and were extubated. Of 96 patients who were extubated, 85 (88%) underwent successful extubation and 11 (12%) underwent unsuccessful extubation. 12 (11.11%) patients did not had acceptable ABG and were chosen to have other modes of weaning.

Table 3: Patients who had acceptable arterial blood gas and were extubated along with patients without acceptable arterial blood gas and were chosen to other modes of weaning after passing spontaneous breathing trial

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[Table 4] showed that of 11 patients who underwent reintubation, the cause of reintubation was hypoxemia in 5 (45.45%), neurological impairment in 4 (36.36%), and hypercapnia in 2 (18.18%) patients.

Table 4: Causes of reintubation

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[Table 5] shows that it shows that none of hemodynamic, respiratory, and ABG parameters were statistically significant (P > 0.05) in extubation success and failure patients.

Table 5: Comparing the characteristics of extubated and not extubated group of patients after successful spontaneous breathing trial and arterial blood gas

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[Table 6] shows RSBI for successful extubation and unsuccessful extubation along with other variables.

Table 6: Rapid shallow breathing index for successful extubation and unsuccessful extubation along with other variables

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[Table 7] shows change in physiologic variables of successful extubation and extubation failure. It shows that there was no statistically significant (P > 0.05) difference between the physiologic variables HR, RR, and MAP between successful and unsuccessful extubation.

Table 7: Change in physiologic variables of successful extubation and extubation failure

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Age, sex, hemoglobin, MV days, and comorbid conditions such as chronic obstructive pulmonary disease (COPD), diabetes mellitus (DM), HTN, chronic kidney disease (CKD), and hemodynamic, respiratory, and ABG parameters were analyzed as a risk factor for extubation failure. All other factors except COPD and MV days were found to statistically insignificant (P > 0.05).

[Table 8] shows that COPD and MV days were statistically significant to cause extubation failure.

Table 8: Risk factors for extubation failure

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Discussion

The mean RSBI for patients with successful extubation was 55.00 ± 17.05 and 52.24 ± 13.71 for patients with unsuccessful extubation and is not statistically significant (P = 0.607). This is different than the study conducted by Fadaii et al.,^[8] which showed that RSBI was 66 ± 57.2 and 76.9 ± 28.1 for successful and failed extubation, respectively. This difference may be due to small sample size, and this study was not designed or intended to assess the outcome of weaning and/or establish a new cutoff value for the RSBI that can the best discriminate between successful and failed extubation outcomes, although our current findings warrant future outcome studies to identify such cutoff values.

The present study shows that 12% of patients had extubation failure. Chest Physicians/American Thoracic Society Clinical Practice guideline for the liberation from MV^[3],[4] showed extubation failure of 24.5%. In the study by Khamiees et al.^[9] and El Solh et al.,^[10] extubation failure was 19.78% and 21%, respectively. In other studies, the percentage varied from 8% to 16%.^{[1],[11],[12],[13],[14],[15],[16]}

Regarding risk factors for extubation failure in this study,

Duration of MV days: The present study showed duration of MV to be statistically significant to cause extubation failure (P = 0.024). A study conducted by El Solh et al.^[10] showed that length of intubation was independently associated with the extubation failure. Meta-analysis conducted by Wang et al.^[17] also showed that duration of MV was statistically significant (P = 0.006) to cause extubation failure
COPD: The present study showed that COPD was statistically significant to cause extubation failure (P = 0.003). A study conducted by El Solh et al.^[10] showed that COPD was independently associated with extubation failure. A study conducted by Robriquet et al.^[18] showed that extubation failure was high in COPD patients. Similarly, a study conducted by Thille et al.^[19] showed that extubation failure occurred in 34% of patients with chronic respiratory diseases (P < 0.01).

COPD patients have mechanical and gas exchange abnormalities and systemic inflammation with muscle wasting and weakness, which increases the risk of reintubation in COPD patients.^[20] In addition, chronic bronchitis with increased airway secretions could contribute to weaning failure.

In this study, other factors such as age, sex, hemoglobin, SOFA score, MAP, DBP, SBP, CKD, DM, and HTN were statistically insignificant to cause extubation failure (P > 0.05), which is similar to other studies.^{[9],[11],[12],[13],[16],[18],[19],[21]}

Studies have shown that advanced age is a risk factor for extubation, but it was not seen in our study.^[22] Positive fluid balance has been shown to cause extubation failure, but it was not studied in our patients.^[23]

In this study, the causes of reintubation were hypoxemia (45.45%) and neurological impairment (36.36%) followed by hypercapnia (18.18%), which is similar to other studies.^[9],[11]

Limitation of the study

It was a single-center study and single method of weaning was used.

Conclusion

RSBI was found to have a poor predictive value for identifying extubation success. Duration of MV of >2 days and COPD were identified as independent risk factors for extubation failure. We need a composite scoring system to predict extubation success.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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