Unsuccessful Extubation Research Articles

Weaning from mechanical ventilation

Mechanical ventilation is often required by very preterm infants with respiratory failure, even if invasive respiratory support is related to lung injury and adverse neurologic outcomes. The exposure to mechanical ventilation should be therefore limited. Optimal extubation however remains challenging, as approximately 30% of intubated preterm infants fails attempted extubation due to poor respiratory drive, atelectasis, residual pulmonary function abnormalities or intercurrent illness. This review outlines the advantages of different weaning strategies that should be considered by neonatologists for current use to reduce unsuccessful extubation.

Factors promoting successful extubation: An audit of planned extubations in preterm infants following the implementation of nursing guidelines

Reintubation, following an unsuccessful extubation from mechanical ventilation is traumatic for the infant and the family. This paper examines the increased success rate of extubations in one tertiary unit following the introduction of nursing guidelines for extubation. In the sample of 19 babies, 17 remained extubated for more than 48 h. The discussions within this paper will examine factors such as the mode of ventilation that the babies were on prior to extubation, the timing of handling pre and post-extubation and the position that they were nursed in after removal of the endotracheal tube. There is also discussion around areas where the nursing guidelines were not adhered to, and the reasons as to why this might be. The conclusion though is that there is some tentative evidence to support the use of nursing guidelines to improve outcomes for infants, although this is based on a small study.

Evaluation of Risk Factors for Postoperative Prolonged Intubation in Premature Infants After Cryotherapy for Retinopathy of Prematurity

Premature infants are more prone to cardiorespiratory complications after surgery than term infants. Risk factors for postoperative apnea include post-conception age, gestational age, postnatal age, birth weight, history of respiratory distress syndrome, bronchopulmonary dysplasia, anemia, necrotizing enterocolitis, use of opioids or nondepolarizing muscle relaxants, aminophylline use, history of apnea, body weight at operation, and pre-existing disease. The aim of this study was to identify the most important factors associated with postoperative extubation and respiratory outcomes among premature infants undergoing cryotherapy for retinopathy of prematurity (ROP). We retrospectively analyzed the clinical records of 62 premature infants, with mean +/- standard deviation gestational age of 26.4 +/- 2.3 weeks, birth weight of 914.8 +/- 208.5 g, postconception age of 37.0 +/- 2.8 weeks, and body weight at the time of operation of 1970.0 +/- 446.8 g, who underwent cryotherapy for ROP. Only 17 infants were successfully extubated within 2 hours after operation. The most predictive factor for successful or unsuccessful extubation was body weight at the time of operation. Body weight at the time of operation was the most important factor associated with postoperative ventilatory support among premature infants under-going cryotherapy for ROP.

Swallowing Disorders as a Predictor of Unsuccessful Extubation: A Clinical Evaluation

Unsuccessful extubation may be due to swallowing dysfunction that causes airway obstruction and impairs patients' ability to cough and expectorate. To determine whether swallowing assessment before extubation is helpful in predicting unsuccessful extubation due to airway secretions. This prospective study included all patients intubated orotracheally for more than 6 days. Before extubation, 3 tests designed to assess (1) cervical, oral, labial, and lingual motility; (2) gag reflex; and (3) swallowing were used at the bedside. Causes of reintubation were identified, and their relationship to patients' swallowing function before extubation was evaluated. Sixty-two patients were enrolled. Data on 55 patients reintubated for swallowing dysfunction were analyzed. Nine patients were reintubated because of obstruction related to upper airway secretions. Evaluation before extubation enabled prediction of 7 of those 9 unsuccessful extubations. Among the 23 patients with central nervous system disease, 3 of 4 unsuccessful extubations were predicted. According to a multivariate logistic regression model, motility and swallowing were independent predictors of unsuccessful extubation (area under receiver-operating-characteristic curve, 80%). The gag reflex was the only significant predictor of the ability to cough (area under curve, 73%) and excessive pulmonary secretion (area under curve, 67%). Swallowing was an independent predictor of the need for suctioning (area under curve, 78%). Using simple bedside tests to evaluate swallowing before extubation is helpful when deciding whether to extubate patients who have been intubated for more than 6 days. Involvement of nurses in these decisions would improve patients' management.

Extubation or tracheotomy in severe brain injuries

In a prospective manner, the predictive use of clinical and radiological findings for successful extubation and unavoidable tracheotomy after severe traumatic brain injury (TBI) was explored. The course of 120 subjects with unconsciousness for more than 24 hours after traumatic brain injury were analyzed including duration of intubation, rate of unsuccessful extubation, and rate of tracheotomy (before transfer to rehabilitation). The incidence of unsuccessful extubations, as well as the period of intubation correlated significantly with the duration of coma. There was also a negative influence on rate of tracheotomy. We found a correlation of coma depth (24 hours after TBI) and period of intubation. However, this was only constituted when comparing the data with the Bruessel Coma Score. The severity of the brain stem damage, as calculated from the MRI classification of brain injured patients, allowed prediction of the length of intubation, the rate of unsuccessful extubation and of tracheotomy while the patient was still comatose. Nevertheless, a brain stem lesion on MRI was no exclusion criterion for successful extubation. The Injury Severity Score, Glasgow Coma Score, parameters from initial cerebral computer tomography, and from monitoring of intracranial pressure or cerebral perfusion pressure did not correlate. These study results encourage the use of MRI data for prediction in the weaning period after severe TBI.

Evaluation of the role of noninvasive positive pressure ventilation in prevention of postextubation respiratory failure in high-risk patients

Unsuccessful extubation (the need for reintubation) occurs in up to 20% of patients within 24–72 hours of planned extubation. Factors that appear to increase the risk are age >70 years, higher severity of illness at weaning onset, use of intravenous sedation, and longer duration of mechanical ventilation prior to extubation [1]. Reintubation is associated with increased hospital stay and mortality [2]. Noninvasive positive pressure ventilation (NIPPV) has been proposed in the management of acute respiratory failure occurring in the postextubation period. The use of NIPPV to prevent postextubation respiratory failure must therefore be considered.

Prediction of ventilation weaning outcome: children are not little adults

Prediction of ventilation weaning outcome in children is important, as unsuccessful extubation increases both morbidity and mortality. Adult weaning criteria are poor predictors of weaning outcome in children for several possible reasons: the length of mechanical ventilation is generally much shorter, and the weaning failure rate is lower in children (thus larger patient numbers are required); integrated weaning indices, such as the rapid shallow breathing index, do not account for normal developmental changes in respiratory function; and the heterogeneity of mechanically ventilated children is greater than in adults. The challenge remains to find universal weaning outcome predictors in children.

Impact of a nurses' protocol-directed weaning procedure on outcomes in patients undergoing mechanical ventilation for longer than 48 hours: a prospective cohort study with a matched historical control group

IntroductionThe aim of the study was to determine whether the use of a nurses' protocol-directed weaning procedure, based on the French intensive care society (SRLF) consensus recommendations, was associated with reductions in the duration of mechanical ventilation and intensive care unit (ICU) length of stay in patients requiring more than 48 hours of mechanical ventilation.MethodsThis prospective study was conducted in a university hospital ICU from January 2002 through to February 2003. A total of 104 patients who had been ventilated for more than 48 hours and were weaned from mechanical ventilation using a nurses' protocol-directed procedure (cases) were compared with a 1:1 matched historical control group who underwent conventional physician-directed weaning (between 1999 and 2001). Duration of ventilation and length of ICU stay, rate of unsuccessful extubation and rate of ventilator-associated pneumonia were compared between cases and controls.ResultsThe duration of mechanical ventilation (16.6 ± 13 days versus 22.5 ± 21 days; P = 0.02) and ICU length of stay (21.6 ± 14.3 days versus 27.6 ± 21.7 days; P = 0.02) were lower among patients who underwent the nurses' protocol-directed weaning than among control individuals. Ventilator-associated pneumonia, ventilator discontinuation failure rates and ICU mortality were similar between the two groups.DiscussionApplication of the nurses' protocol-directed weaning procedure described here is safe and promotes significant outcome benefits in patients who require more than 48 hours of mechanical ventilation.

Risk of Extubation Failure in Patients With Myasthenic Crisis

Weaning patients with myasthenic crisis (MC) from mechanical ventilation is often difficult, and the ideal time for extubation is often uncertain. However, little is known about the risk of extubation failure and the factors that may affect its occurrence. The goals of this study were to assess the risk of extubation failure in patients with MC and to determine which clinical variables may predict unsuccessful extubation. Retrospective review of consecutive patients admitted for MC. Weaning method was categorized as T-piece or continuous positive airway pressure (i.e., T-piece trials not performed). Extubation failure was defined as need for reintubation or tracheostomy due to persistent neuromuscular insufficiency. Functional outcome was assessed using the modified Rankin score. We identified 26 episodes of MC in 20 patients. Median age was 42.1 years (range 14-83 years). Most patients were treated with immunomodulatory therapy (73%). There were seven episodes of extubation failure (prevalence rate 27%). Median time to reintubation was 36 hours. Older age (p = 0.05), atelectasis (p < 0.01), and pneumonia (p =0.02) were significantly associated with extubation failure. Patients with failed extubation had considerably prolonged intensive care unit stays (median 28 versus 7 days; p < 0.01) and hospital stays (median 40 versus 12 days; p < 0.01). Extubation failure may often complicate MC. Older age and development of pulmonary complications during mechanical ventilation increase the risk of extubation failure.

Weaning newborns from mechanical ventilation

While there is a relative consensus as to whether mechanical ventilation should be initiated, the management of babies during recovery from respiratory failure remains largely subjective and is predominantly determined by institutional or individual practices or preferences. This can lead to babies either being left on the ventilator too long, or extubated too hastily, thus requiring repeated re-intubation. The current scientific literature fails to provide a uniform view of the most appropriate way to wean babies from mechanical ventilation. This might stem from a lack of understanding of the relative merits of the different techniques of discontinuing mechanical ventilation, given the availability of a variety of primary ventilatory modes which were not available to a neonatal population before, and limited research into the pathophysiological mechanisms responsible for an unsuccessful extubation. The purpose of this paper is to review the physiological, mechanical, and clinical principles of weaning, and to highlight areas still in need of investigation.

Predictors of Extubation Outcome in Patients Who Have Successfully Completed a Spontaneous Breathing Trial

After patients recovering from respiratory failure have successfully completed a spontaneous breathing trial (SBT), clinicians must determine whether an artificial airway is still required. We hypothesized that cough strength and the magnitude of endotracheal secretions affect extubation outcomes. We conducted a prospective study of 91 adult patients treated in medical-cardiac ICUs who were recovering from respiratory failure, had successfully completed an SBT, and were about to be extubated. A number of demographic and physiologic parameters were recorded with the patient receiving full ventilatory support and during the SBT, just prior to extubation. Cough strength on command was measured with a semiobjective scale of 0 to 5, and the magnitude of endotracheal secretions was measured as none, mild, moderate, or abundant by a single observer. In addition, patients were asked to cough onto a white card held 1 to 2 cm from the endotracheal tube; if secretions were propelled onto the card, it was termed a positive white card test (WCT) result. All patients were then extubated from T-piece or continuous positive airway pressure breathing trials. If 72 h elapsed and patients did not require reintubation, they were defined as successfully extubated. Ninety-one patients with a mean (+/- SE) age of 65.2 +/- 1.6 years, ICU admission APACHE (acute physiology and chronic health evaluation) II score of 17.7 +/- 0.7, and duration of mechanical ventilation of 5.0 +/- 0.5 days were studied over 100 extubations. Sixteen patients could not be extubated, and 2 patients underwent two unsuccessful extubation attempts, for a total of 18 unsuccessful extubations. Age, severity of illness, duration of mechanical ventilation, oxygenation, rapid shallow breathing index, and vital signs during SBTs did not differ between patients with successful extubations vs patients with unsuccessful extubations. The WCT result was highly correlated with cough strength. Patients with weak (grade 0 to 2) coughs were four times as likely to have unsuccessful extubations, compared to those with moderate-to-strong (grade 3 to 5) coughs (risk ratio [RR], 4.0; 95% confidence interval [CI],1.8 to 8.9). Patients with moderate-to-abundant secretions were more than eight times as times as likely to have unsuccessful extubations as those with no or mild secretions (RR, 8.7; 95% CI, 2.1 to 35.7). Patients with negative WCT results were three times as likely to have unsuccessful extubations as those with positive WCT results (RR, 3.0; 95% CI, 1.3 to 6.7). Poor cough strength and endotracheal secretions were synergistic in predicting extubation failure (Rothman synergy index, 3.7; RR, 31.9; 95% CI, 4.5 to 225.3). Patients with PaO(2)/fraction of inspired oxygen (P:F) ratios of 120 to 200 (receiving mechanical ventilation) were not less likely to be successfully extubated than those with P:F ratios of > 200, but those with hemoglobin levels < or = 10 g/dL were more than five times as likely to have unsuccessful extubations as those with hemoglobin levels > 10 g/dL. After patients recovering from respiratory failure have successfully completed an SBT, factors affecting airway competence, such as cough strength and amount of endotracheal secretions, may be important predictors of extubation outcomes. Also, a majority (89%) of medically ill patients with P:F ratios of 120 to 200 (four of five patients with P:F ratios from 120 to 150), values sometimes used to preclude weaning, were extubated successfully.

Comparison of predictors of extubation from mechanical ventilation in children.

OBJECTIVE: Unsuccessful extubation from mechanical ventilation increases mortality and morbidity. Therefore, the identification of an accurate predictor of successful extubation is desirable. This study was designed to determine whether the results of easily performed respiratory measurements, particularly if reported as "combined extubation" indices, were better predictors of extubation failure in a pediatric population than were readily available clinical data. DESIGN: Prospective observational study. SETTING: Tertiary pediatric intensive care unit. PATIENTS: All children who required mechanical ventilation for >/=24 hrs during a 12-month period and whose parents gave informed written consent. INTERVENTIONS: Respiratory function measurements were made (on average) 7 hrs (range, 0.2-25.0 hrs) before extubation. Arterial blood gas results were obtained immediately before extubation. The values of each predictor associated with maximum sensitivity and specificity were determined, and the areas under receiver operator characteristic curves were compared to determine the most accurate predictor of successful extubation. MEASUREMENTS AND MAIN RESULTS: A total of 47 children (mean age, 3.90 yrs; range, 0.10-17.3 yrs) were studied; extubation failed in 7. A low tidal volume (<7.5 mL/kg) and a low minute volume (<250 mL/kg) had the highest sensitivities (86% and 71%, respectively) and specificities (61% and 71%, respectively) in predicting extubation failure. The a/A ratio performed least well in predicting extubation failure (area under the receiver operating characteristic curve, 0.51). CONCLUSIONS: Volume measurements during pediatric mechanical ventilation may facilitate successful extubation.

Minimum alveolar concentration of desflurane for tracheal extubation in deeply anaesthetized, unpremedicated children

We have studied 25 children, aged 4-9 yr, to determine the minimum alveolar concentration (MAC) of desflurane at which safe tracheal extubation can be performed in deeply anaesthetized children. The end-tidal concentration of desflurane was noted at tracheal extubation. Successful extubation was defined as one in which there was no coughing or bucking on the tracheal tube during suctioning of the pharynx, no movement or coughing within 1 min of tracheal extubation and no breath-holding or laryngospasm after extubation. Successful extubation was followed by extubation at a concentration of 0.5% less, and so on in subsequent subjects, until unsuccessful extubation occurred. After a reaction, the percentage was increased in the next patient, continuing up and down in pairs, until the required number of subjects was achieved. In 50% of children aged 4-9 yr, tracheal extubation may be accomplished without coughing or moving at an end-tidal concentration of 7.7%. The end-tidal concentration of desflurane to achieve satisfactory extubation in 95% of children was 8.5%.

Noninvasive Face Mask Mechanical Ventilation in Patients with Acute Hypercapnic Respiratory Failure

Mechanically assisted intermittent positive-pressure ventilation effectively provides ventilatory support in patients with respiratory failure but it requires placing an artificial airway. We have previously reported our successful experience delivering mechanical ventilation via a face mask (FMMV) rather than with an endotracheal tube in a pilot study of patients with acute respiratory failure. The present investigation evaluated an additional 18 patients with hypercapnic respiratory failure to determine the efficacy of FMMV in a more homogeneous group and to determine factors predicting its success. FMMV was successful in avoiding intubation in 13 of the 18 patients. A significant initial improvement in PCO2 (greater than 16 percent decrease) and in pH (from less than 7.30 to greater than 7.30) predicted success. The five patients who failed on FMMV required endotracheal intubation because of inability to improve gas exchange (three patients), apnea due to sedatives (one patient), and management of secretions (one patient). FMMV was generally well accepted with only two patients withdrawn because of intolerance of the mask. The mean duration of FMMV was 25 h. Complications were seen in only two patients (11 percent): aspiration (one patient) and mild skin necrosis (one patient). Seven patients entered the study by meeting entrance criteria after an unsuccessful extubation attempt and therefore received both forms of mechanical ventilation. All but one patient avoided reintubation, and the face mask proved to be as effective as the endotracheal tube as a conduit for delivering the mechanical tidal volume and improving gas exchange. Our findings indicate that FMMV is a viable option for short-term (one to four days) ventilatory support of patients with hypercapnic respiratory failure and insufficiency.