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Journal Reading : Characteristics and Outcomes in Adult Patients Receiving Mechanical VentilationJasreena Kaur S.11-2013-165

Information about the mortality of the patients requiring mechanical ventilation is important allows for better counselling of patients and their families The multivariate analysis showed that factors independently associated with an increased mortality rate were age, multiorgan system failure,human immunodeficiency virus infection,chronic liver disease and cancerIntroductionObjective of the study :

To determine the survival and the relative importance of many factors influencing survival of mechanicallly ventilated patients such as baseline characteristics,ventilatory settings, and organ failure developing over the course of the mechanical ventilation

Study DesignProspective cohort study of consecutive adult patients admitted to 361 ICUs in 20 countries and who received mechanical ventilation for more than 12 hoursThe following data was collected : age,sex,weight,simplified acute physiology score II (SAPS II) at the time of admission, chronic functional status,indication for the initiation of mechanical ventilation,and modality of ventilatory support.

MethodsThe following event were assesed daily (maximum 28 days)

-need for tracheal intubation in patients receiving noninvasive mechanical ventilation-ARDS-Barotrauma -pneumonia-sepsis-renal failure-hepatic failure-coagulopathyDuration of mechanical ventilation was defined as the elapsed from the initiation of ventilatory support to the onset of weaning.

Statistical AnalysisAll variants were grouped in 3 categories 1.Factors present at start of the mechanical ventilation2.Factors related to patient management 3.Events occuring over the course of mechanical ventilation

Mechanical ventilation was delivered through an orophareangal tube in 89 % , a nasotracheal tube in 4.1 % ,a facial mask in 4.9 %, and a tracheostomy in 2.0 % patients.85 % patients with COPD received non invasive ventilation and 25.9 % subsequently required tracheal intubation Of the 148 patients with ARF who received non invasive ventilation, 54 (36.5 %)subsequently required tracheal intubation

Results

A total of 5199 weaning attempts were undertaken in 3640 patients (70.2 %) using the following methods-once daily (77.8 %)-multiple weaning (14.0%)-gradual reduction of pressure support (20.7%)-gradual reduction of synchronized intermittent mandatory ventilation (8.5%) -gradual reduction in the simultaneous use of synchronized intermittent mandatory ventilation and pressure support (21.8%)Patients experienced the following during mechanical ventilation:-ARDS (4.0%)-Barotrauma (3.0%)-pneumonia (9.8%)-sepsis (9.7 %)-shock (22.1 %)-renal failure ( 18.7 %)-hepatic failure (6.3%)-coagulopathy (10.6)-respiratory acidosis (5.6%)-metabolic acidosis (6.0%)

Survival in patients with respiratory failure who required mechanical ventilation for more than 12 hours was 69% and depended not only on factors present when initiating mechanical ventilation but mainly on the : -developmental of complications -changes in monitored variables-patient management during the subsequent courseCommentMortality is not independently associated with the patients sex.Hospital mortality of 28% in patients with COPD receiving mechanical ventilation due to an acute excacerbation of their diseasePatients receiving mechanical ventilation due to an acute decompessation of COPD had significantly lower mortality rate than patients receiving mechanical ventilation because of ARF and other etiologies.

In the present studies , survival was 23 % lower in patients who developed ARDS in 48 hours after the the start of mechanical ventilation than in patients who had it when the ventilation was instituted.The only factors independently associated with the descreased survival were : -coma,ARDS and sepsisThe only factor independently associated with the increased survival rate was postoperative state.

Both factors at baseline and complications of critical illness over time influence the outcome of patients receiving mechanical ventilation.Future controlled trials of ventilator strategies evaluating mortality need to take into account not only variables evident at the time of randomization but also developments that occur later in the course of mechanical ventilation.SummaryThank You