الفهرس 
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Abstract
This study aimed to assess the outcome of mechanically ventilated chronic obstructive pulmonary disease (COPD) patients admitted in Respiratory ICU in Zagazig University hospitals in year 2014 and the factors influencing it.
The study was done in chest department intensive care unit, internal medicine ICU and anaesthesia ICU, Zagazig university hospitals in the period from November 2013 until January 2015.
This study included all COPD patients in acute on top of chronic respiratory failure who are candidates for mechanical ventilation according to GOLD 2014.
• COPD patients were diagnosed according to GOLD 2014, including; clinical criteria, clinical history with compatible physical findings, and/or evidence of hyperinflation on chest radiograph.
• Premorbid or post recovery pulmonary function test (FEV1/FVC<70%) when available.
• All patients were candidates for invasive mechanical ventilation (IMV) according to GOLD (2014):
• Severe dyspnea with use of accessory muscles and paradoxical abdominal motion.
• Respiratory frequency> 35 breaths per minute.
• Severe acidosis (pH<7.25) and hypercapnia (PaCO2> 60 mmHg).
• Respiratory arrest.
• Somnolence, impaired mental status.
• Cardiovascular complications (hypotension, shock, heart failure).
• NIPPV failure.
• The following were done for all patients:
1- Thorough medical history with special concentration on special habits.
2- Past history including, atopic manifestations (dermatitis, allergic rhinitis), frequency of exacerbation in the last year, past history of mechanical ventilation, medications used for COPD, patient compliance for such medications and for other co-morbidities if present.
3- Routine and specific investigations including the following: CXR (PA and lateral views), HRCT was done for those with manifestation of hyperinflation in CXR (emphysematous pattern).
4- CBC, ESR, CRP and serum albumin, phosphorus, magnesium,
5- Serum IgE, peripheral blood total and differential leukocytic count for oesinophil count for those with history suggestive for allergic rhinitis or atopic dermatitis.
6- Sputum (tracheal aspirate) culture and sensitivity, and eosinophilic count.
7- Serial arterial blood gas (ABGs) immediately before intubation, during the period of MV and at the onset of weaning from MV.
8- Recent echocardiography, or old one if done within the period between the current and previous exacerbation.
9- Pulmonary function tests (PFT), post recovery if not available.
Determination of COPD phenotype
Mixed COPD-Asthma Phenotype
Diagnosed by the presence of any combination of the following factors:
1. History of asthma and/or atopic dermatitis, allergic rhinitis.
2. Air flow limitation not fully reversible but often with current or historical variability (GINA 2014).
3. Notable eosinophilia in respiratory and/or peripheral secretions
4. High serum IgE
• Exacerbator Phenotype
The Exacerbator phenotype was identified with the existence of two or more exacerbations per year; the exacerbations should be separated at least 4 weeks after the end of the treatment of the previous exacerbation or 6 weeks from the start of the exacerbation in cases that have not received treatment.
• Emphysema-Hyperinflation Phenotype
Diagnosed with HRCT, which is able to demonstrate areas of low attenuation with reduction in the vessels. Different thresholds have been used to define the level below which emphysema is said to be present ranging from-900HU to -960HU. CT scans also give information on type of emphysema.
• Chronic bronchitis phenotype
Defined as cough and expectoration for at least 3 months of the year for 2 consecutive years.
10- Past history of co-morbidities, co-morbid conditions recorded e.g. immunosuppression, liver cirrhosis, congestive heart failure [CHF], and chronic renal failure), excluding other respiratory conditions
11- Data obtained during the hospitalization were recorded and at the onset of weaning from MV before the spontaneous breathing trial that led to an extubation attempt.
12- All patients were sedated by using Midazolam (15mg) by a dose of 0.2 mg /kg slowly intravenous during intubation as it is available in ICU. Midazolam is rapidly acting sedative, with a short duration of action less than 2 hours when given intravenous.
All patients were put on SIMV mode plus PSV (15-22cm H2O) according to the protocol used in ICU .
a. Oxygen concentration: started by FIO2 100% then adjusted by arterial blood gases (ABGs) to keep PaO2 ≥ 60 mmHg and SaO2
≥ 90%.
b. Tidal volume (VT): set at 6-8 ml/kg.
c. Respiratory rate: set at 12 – 14 breaths/min.
d. Trigger sensitivity: set at -0.5 to -1 cm H2O.
e. Inspiratory flow rate: set at 50 to 80 L/min.
f. Positive end expiratory pressure (PEEP) : 0 - 10 cm H2O.
g. No inspiratory pause.
The aim of these parameters was to keep the patient’s PaO2 just above 60 mmHg.
The present study included 106 COPD patients with acute on top of chronic respiratory failure, all were candidates for invasive MV according to GOLD 2014 criteria, they were 34 females and 72 males, 20 nonsmokers, 86 smokers, the patients were classified into the clinical phenotypes according to Celli et el., 2008, Mair et al., 2010, 35 patients showed emphysematous phenotype, 32 were exacerbator, 14 were chronic bronchitic phenotype ,25 patients with asthma COPD overlap phenotype.70 patients were successfully weaned (good outcome) 36 cannot be weaned after the initial SBT (bad outcome), 33 of them died while on MV and three patients were weaned thereafter.
This study revealed the following results:
The higher mortality was found among patients with advanced age.
Gender, smoking habits, smoking degree of the patients didn’t account for any statistical difference between good and bad outcome.
There was no statistically significant difference between both groups regarding clinical parameters (p>0.05) except for temperature as bad outcome group was with higher temp (p <0.05).
There was no statistically significant difference between both groups regarding laboratory parameters and pulmonary function (p>0.05).
There was no statistically significant difference regarding ABG (p>0.05) except for HCO3 which was higher in bad outcome group than good outcome group.
There was statistically significant difference between both groups regarding; duration of MV, interval from last exacerbation and last year number of exacerbations as duration of MV and last year number of exacerbations were higher in bad outcome group than in good outcome group, interval from last exacerbation was shorter in bad outcome group than in good outcome. There was statistically significant difference in both groups regarding dyspnea, increasing last year no of exacerbations, past history of MV, Compliance to TTT and complications as risk factors for bad outcome.
There was statistically significant difference in both groups regarding emphysema phenotype, as risk factors for bad outcome.