Original contributionPredicting the need of tracheostomy amongst patients admitted to an intensive care unit: A multivariate model☆
Introduction
Mechanical ventilation is often imperative in many cases of acute respiratory failure, and thus a common reason for admission to an intensive care unit (ICU). Recent data have shown that approximately one in three patients in an ICU is admitted because of the need of ventilatory support, and of these, 5 to 10% will require prolonged mechanical ventilation [1], [2].
With a standardized definition lacking in the literature, researchers have used wide cutoff points when referring to the abovementioned entity, which often range from 24 hours to 21 days [1], [3], [4]. In spite of this situation, these patients are consistently reported to be at an increased risk of death, cognitive decline, and functional dependence and to have an overall poorer quality of life [1].
In order to prevent these complications, many authors have considered tracheostomies to be a suitable option. This procedure has been shown to shorten overall hospital stays, decrease the incidence of ventilator-associated pneumonia, upper airway injuries (including vocal cord ulceration) and in-hospital mortality; although the evidence has to date yielded mixed results [5], [6], [7]. These benefits are theoretically explained in clinical benefits that are to be obtained from tracheostomy, which include lower airway resistances, easier and safer tracheal suction, improved patient comfort and communication, the possibility of oral feeding and faster weaning from the ventilator [4], [8], [9]. All of these benefits are likely to be improved by optimal procedure timing, with an increasing interest in the medical literature for early, rather than late, tracheostomies. A recent systematic review that included both randomized and non-randomized trials found that early tracheostomy significantly reduced duration of artificial ventilation (mean difference of − 8.5 days, 95% confidence intervals, 95% CI: − 15.3 to − 1.7 days) and length of stay in intensive care (mean difference of − 15.3 days; 95% CI − 24.6 to − 6.1 days) [10]. Beneficial results were also suggested in another systematic review by the Cochrane Collaboration composed of four randomized trials, although the authors warned that their estimates could be biased due to a perceived high risk of systematic error amongst included studies [11].
Being able to predict which patient will require prolonged ventilatory assistance could prove important for clinical practice. The proper recognition of the patient at risk would permit the early establishment of potentially useful therapies, such as tracheostomies. Therefore, we aimed at developing a predictive model that would help clinicians detect patients at increased risk of prolonged mechanical ventilation.
Section snippets
Patients and methods
A retrospective cohort study was undertaken amongst patients admitted to the intensive care unit of the Hospital Naval Almirante Nef between June 2011 and June 2012. All patients older than 18 years who required mechanical ventilation and were therefore subject to an orotracheal intubation were considered for inclusion. Patients who had been intubated in other hospitals or ICUs, those that had an intubation method other than orotracheal (i.e. nasopharyngeal, larynx mask) and patients that
Results
During the observation period, a total of 349 patients were admitted to the ICU. One hundred forty-two (40.7%, 95% CI: 35.5–46%) were intubated due to the need of invasive mechanical ventilation, and all of these patients were included in this retrospective cohort.
The study sample consisted of mostly male inpatients (60.5%) with a mean age of 65.8 ± 16.7 years. The overall burden of comorbidities was considered to be moderate, with a median Charlson Index of two points (IQR: 1–3 points). Anemia
Discussion
The observed incidence of prolonged mechanical ventilation, defined as the requirement of invasive ventilatory support for 7 days or more, was nearly one-fourth of the intubated patients in this cohort. Other studies on the subject have observed different incidences, which is likely associated to the important heterogeneity that can be seen when defining the concept of prolonged intubation. Studies that are conducted in coronary intensive care units often use 72 hours as a threshold when
Acknowledgments
We are thankful of Ms. Lin-Pha Chiang and Ms. Macarena Tobar for their valuable assistance in collecting data for the present study.
References (31)
- et al.
Prolonged mechanical ventilation probability model
Med Intensiva
(2012) - et al.
A new method of classifying prognostic comorbidity in longitudinal studies: development and validation
J Chronic Dis
(1987) - et al.
Is the duration of mechanical ventilation predictable?
Chest
(1997) - et al.
Acute kidney injury on ventilator initiation day independently predicts prolonged mechanical ventilation in intensive care unit patients
J Crit Care
(2011) - et al.
Shock on admission day is the best predictor of prolonged mechanical ventilation in the ICU
Chest
(2005) - et al.
Frailty: an emerging geriatric syndrome
Am J Med
(2007) - et al.
Frailty in elderly people
Lancet
(2013) - et al.
Intraoperative changes in hyponatremia as a risk factor for prolonged mechanical ventilation after living donor liver transplantation
Transplant Proc
(2010) - et al.
Bias and causal associations in observational research
Lancet
(2002) - et al.
A simulation study of the number of events per variable in logistic regression analysis
J Clin Epidemiol
(1996)
Hypoactive delirium after cardiac surgery as an independent risk factor for prolonged mechanical ventilation
J Cardiothorac Vasc Anesth
Physiologic determinants of prolonged mechanical ventilation in patients after major surgery
J Crit Care
Lactic acidosis: recognition, kinetics, and associated prognosis
Crit Care Clin
Detection of hypoxia at the cellular level
Crit Care Clin
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Conflict of interest statement: none to disclose.