Delia Teresita Moreno-González,1 Jorge Enrique Camacho-Sánchez,2 Ángela Silvia Sánchez-Juárez,3 Antonio Urbina-Zeglen,4 Leticia Isabel Samaniego-Ríos,5 Rosario Velarde-Zúñiga1
1,3,4,5Instituto Mexicano del Seguro Social, Hospital General con Medicina Familiar 18, Torreón, Coahuila, México
1Unidad de Vigilancia Edipemiológica, 2Instituto Mexicano del Seguro Social, Unidad de Medicina Familiar 66, Educación e Investigación en Salud, 3Servicio de Medicina Interna, 4Dirección Médica, 5Jefatura de Medicina Interna
Correspondence: Delia Teresita Moreno-González
Received: February 23rd 2015
Judged: May 19th 2016
Accepted: October 10th 2016
Introduction: Ventilator-associated pneumonia (VAP) is a lung infection that occurs 48 hours or more after endotracheal intubation in patients undergoing mechanical ventilation.
Objective: To use the Clinical Pulmonary Infection Score (CPIS) in order to identify the presence of VAP in patients with endotracheal intubation.
Methods: Descriptive, cross-sectional study, which included 53 patients with mechanical ventilation, out of which only 11 met the selection criteria. Patients were assessed with the CPIS, as well as with their results of blood count, chest X-ray, and culture of endotracheal aspirates.
Results: 81.9% were male, with a mean age of 65.09 ± 13.4 years, weight 75.7 ± 13.5 kg, height 1.61 ± 0.21 cm. The main cause of mechanical ventilation was neurological in 36.4%, and pulmonary in 27.3%. Of all the microorganisms isolated, the one with the highest estimated rate was Pseudomonas aeruginosa. Enterobacter cloacae and Pseudomonas aeruginosa showed drug resistance to all antibiotics.
Conclusion: The use of the scale for evaluating patients with mechanical ventilation helps to identify the presence of ventilator-associated pneumonia.
Keywords: Focal infection; Pneumococcal pneumonia; Nursing staff; Intubation, Intratracheal
Ventilator-associated pneumonia (VAP) is inflammation of the lung parenchyma caused by an infectious process that was acquired after 48 hours of hospital stay, which was not incubated at the patient's admission and can manifest up to 72 hours after their discharge.1,2,3
The pathogenesis of VAP is mainly associated with the effect of intubation and the endotracheal tube, since it facilitates tracheobronchial colonization. In addition, oropharyngeal and gastric colonization by gram-negative enteric microorganisms is an event that precedes tracheobronchial colonization and is associated with the presence of exogenous and endogenous bacterial reservoirs that give rise to colonization of the pulmonary parenchyma.4 The main mechanism in the pathogenesis of VAP, microaspirations are repeated microorganisms colonizing the upper airways through the virtual space between the pneumatic balloon of the endotracheal tube and the trachea wall.
VAP develops due to aspiration of secretions contaminated with pathogenic microorganisms that reach the distal pathway through reflux and mechanical aspiration of contaminated gastric contents, and by repeated inoculation of secretions from the upper airway to the distal tracheal tree.5
It is suggested that enterobacteria come from the endogenous flora of the patient, while nonfermenting gram-negative bacilli come from environmental sources, mainly contaminated hands of health workers or nebulizers.6
VAP has an impact on the patient, their family, and the institution. For the patient and their family, significant costs are generated as the patient remains hospitalized for more time, and productivity is affected because their incorporation to work life is delayed. It also increases physical and emotional exhaustion of the primary caregiver. For the institution, it triggers an additional cost that ranges between 9000 and 31,000 euros per month and for the ICU, 4.3 to 13 additional days of hospital stay. All of this is closely related to the increase in morbidity and mortality rates, hospital admission days, and hospital costs. In Europe, an estimated 16,000 euros corresponds to the costs attributable to the patient with VAP. In the United States, patients pay $10,000 to $40,000 dollars a month.7
In Colombia, VAP causes 15-20% of nosocomial infections in care centers for patients with acute disorders and consequently in intensive care units. In this regard, in the Hospital Militar Central de Bogota, a total of 1944 admissions were reported in 7.8% of the 304 trauma patients.8 The Grupo Nacional de Vigilancia Epidemiológica de las Unidades de Cuidados Intensivos de Colombia (GRUVECO) reports a VAP rate of 7.37 cases per thousand patient days.9
According to the Centers for Disease Control and Prevention (CDC), VAP affects a range of patients ranging between 20% and 25% of those with mechanical ventilation for more than 48 hours, with a additional increment of 1% for each day of mechanical ventilation.
According to the National Nosocomial Infections Surveillance (NNIS) report, the average VAP (episodes/1000 days of ventilation) in the United States is higher in patients hospitalized in the ICU with neurosurgical ailment (15.1); postsurgical ailment (9.9); and in patients with burns (9.6); than in patients in the medical ICU (5) and respiratory ICU (4.2). Established microorganisms include Staphylococcus aureus, Staphylococcus pneumoniae, Haemophylus influenzae, Acinetobacter, Serratia, and Pseudomonas. Among the unusual or emerging microorganisms are Legionella, Moraxella catarrhalis, Stenotrophomonas maltophilia, Aspergillus, and Herpes simplex (HSV-1). Non-pathogens also included in the unusual group are non-pathogenic Staphylococcus coagulase negative, Corynebacterium, Neisseria, Streptococcus viridans, and Candida.10
In hospitalized adult patients, incidence of VAP of 10 to 65% has been estimated.11 Mortality is very high, especially when the infection is caused by microorganisms such as MRSA (methicillin-resistant Staphylococcus aureus), Pseudomonas aeruginosa, and Acinetobacter baumannii, which are more frequent in patients who have previously received antibiotic therapy.6,9
In Latin America, the main gram-negative etiological agents are Acinetobacter, Enterobacteriaceae, and Pseudomonas aeruginosa; and of gram-positive agents, Staphylococcus aureus.12
In the Hospital General de Zona con Medicina Familiar No. 18, a total of 4597 hospital discharges corresponding to the period from February to August of 2014 were quantified. Of these, 20% (915) of the discharges were from the general surgery unit; 32% (1495) from gynecology and obstetrics; 37% (1689) from internal medicine; and 11% (498) from pediatrics. In the same period, the rate of nosocomial infections was 5.8 per 100 days. The VAP rate in February was 106.4 per 1000 days; in March, it was 38.1; in April, 148.1; in May, 74.1; in July, 36.7; and in August, 46.5
Therefore, the objective of the present study was to use the clinical scale of lung infection to identify the presence of pneumonia associated with mechanical ventilation in patients with endotracheal intubation.
A descriptive cross-sectional study was performed at the aforementioned hospital from February to August 2014. For the study, patients hospitalized with mechanical ventilation with no history of respiratory tract infection prior to endotracheal intubation and with a minimum stay of 72 hours were chosen. Patients diagnosed with brain death by the emergency physician or the internist and those diagnosed with pneumonia and endotracheal intubation were not included in the study.
The total number of intubated patients in the study period was 53. Of these, 11 met the inclusion criteria. Of the patients that were not included; 15 were neonates with mechanical ventilation; 7 were extubated before 72 hours; 5 had a pneumonia diagnosis; 14 were deaths of patients with non-VAP diagnoses who had ventilatory support before 72 hours. In addition, there was also a patient with traumatic brain injury who was sent to intensive care at another hospital. In the 11 patients that met the inclusion criteria, a physical examination of the chest was performed at 24 hours and at 48 hours. Chest X-rays were taken, as well as blood biometric samples and tracheal secretion cultures. To determine presence or absence of ventilator-associated pneumonia (VAP), the Clinical Pulmonary Infection Score was applied with a sensitivity estimate of 60% and a specificity of 59%. It should be noted that there is no gold standard for the diagnosis of VAP. A sociodemographic data survey was applied to the relatives of the patients.
The diagnosis of VAP was determined by an internist 72 hours after endotracheal intubation using the Clinical Pulmonary Infection Score, designed in 1991 and modified in 2000 by Singh,13 with the parameters of body temperature, leukocytes, tracheal secretion, PaO2/FiO2, chest X-ray, progression of pulmonary infiltrate, and semiquantitative culture of tracheal secretion. A score≥6 confirmed the existence of pneumonia (Table I).
|Table I. Clinical Pulmonary Infection Score, designed by Pugin in 1991 and amended in,13,14 2000 by Singh|
|≥50% of bands||Add 1|
|Non-purulent secretions present||1|
|Purulent secretions present||2|
|PaO2/FiO2 (mmHg)||>240 or ARDS*||0|
|≤240 in the absence of ARDS*||2|
|Chest X-ray||No infiltrate||0|
|Diffuse or patchy infiltrate||1|
|Progression of pulmonary infiltrate||No progression||0|
|With progression (excluding ARDS and left ventricular failure)||2|
|Semiquantitative culture of tracheal secretions||Negative or minimal growth of pathogenic bacteria
|Moderate or abundant growth of pathogenic bacteria
|Visualization by Gram staining of the same bacterium in which the culture grew||Add 1|
|* Acute respiratory distress syndrome defined by: PaO2 /FiO2≤200, pulmonary wedge pressure≤18 mmHg and radiological bilateral infiltrates. ** Organism predominant in the culture|
The data were processed in SPSS program, version 22. For the quantitative variables we used mean, standard deviation, percentages, and absolute frequencies. The qualitative variables were analyzed with frequencies and percentages.
Of the 11 patients with endotracheal intubation and mechanical ventilation, 81.9% were men (9) and 18.2% were women (2). The mean age was 65±13.45 years, the mean weight was 75.7±13.52 kg, the height was 1.61±0.21 cm and the body mass index was 31.51 (with a standard deviation of 15.51).
The patient's antecedents for endotracheal intubation and assisted mechanical ventilation were renal failure in 45.4% (5); neurological alteration in 36.4% (4); sepsis in 9.1% (1); and cardiovascular disease in 9.1% (1). Only one patient presented a history of ingestion of proton pump inhibitors or H2 blockers prior to intubation.
Of the comorbidity found, systemic arterial hypertension occurred most frequently in 90.9% (10) and diabetes mellitus in 63.6% (7) of the patients (Table II).
|Table II. Comorbidity in hospitalized patients with mechanical ventilation (n=11)|
|Chronic renal failure||Yes||5||45.5|
|Intake of antibiotics prior to intubation||Yes||1||9.1|
|Intake of immunosuppressants prior to intubation||No||11||100|
|Intake of proton pump inhibitors or H2 blockers prior to intubation||No||10||90.9|
Regarding the parameters of the Clinical Pulmonary Infection Score, the average body temperature at 24 hours was 36.6±0.83ºC; at 48 hours, 36.3±0.43ºC; and at 72 hours, 37.2±1.03ºC. The leukocyte count at 72 hours was 14,949.09±6789.94. 54.5% of patients had nonpurulent secretion and 45.46% had purulent secretion. More than half of patients (63.6%) had diffuse pulmonary infiltrates or patches and 36.3% had localized pulmonary infiltrates (Table III).
|Table III. Parameters of patients with mechanical ventilation based on the Clinical Pulmonary Infection Score (n=11)|
|Leucocytes (mm3)||Tracheal secretion||PaO2/FiO2 (mm/Hg)||Rayos X
|Culture of Tracheal secretion||Gram||Score||Microorganism|
Non-purulent secretions present
|>240||Localized infiltrate||With progression||Positive||Positive||9||Enterobacter aerogenes|
Non-purulent secretions present
|≤240||Localized infiltrate||With progression||Positive||Positive||12||Enterobacter cloacae|
|6470||Non-purulent secretions present||≤240||Diffuse or patchy infiltrate
Non-purulent secretions present
|≤240||Diffuse or patchy infiltrate||With progression||Negative||Negative||6||Negative|
Non-purulent secretions present
|≤240||Diffuse or patchy infiltrate||With progression||Positive||Positive||9||Pseudomonas aeuroginosa|
|19300||Purulent secretions present||≤240||Diffuse or patchy infiltrate
|15400||Purulent secretions present||≤240||Diffuse or patchy infiltrate
||No progression||Positive||Positive||8||Staphylococcus aureus|
Non-purulent secretions present
|≤240||Localized infiltrate||With progression||Positive||Positive||10||Escherichia coli|
|21000||Purulent secretions present||>240||Diffuse or patchy infiltrate
||With progression||Positive||Positive||10||Pseudomonas aeuroginosa|
|10400||Purulent secretions present||≤240||Localized infiltrate||With progression||Positive||Positive||10||Pseudomonas aeuroginosa|
|14000||Purulent secretions present||≤240||Diffuse or patchy infiltrate
||With progression||Positive||Positive||12||Klebsiella neumoniae|
It was found that patients with VAP make up 20.7% of all patients with endotracheal intubation and mechanical assisted ventilation. In all cases VAP was present at 72 hours and the result found from the lung infection scale, which obtained a score≥6. A bronchial secretion culture was performed at 72 hours with asepsis and antisepsis on the part of the investigator in charge and was found positive in eight of the patients (72.72%).
Of the isolated microorganisms, the most frequent was Pseudomonas aeruginosa. In addition, two of the microorganisms cultured as Enterobacter cloacae and Pseudomonas aeruginosa presented resistance to all antibiotics.
According to the Centers for Disease Control and Prevention (CDC), VAP affects a range of between 20% and 25% of patients receiving mechanical ventilation for more than 48 hours.10 This situation is similar to that found in the present study in intubated patients (53), since VAP was found in 20.7%.
Comorbidity in patients with VAP was present, mainly hypertension and diabetes mellitus, the latter a risk factor to the immune system.
Causes of death include metabolic acidosis, hemorrhagic cerebral vascular disease, ischemic heart disease, end-stage renal disease, chronic renal failure, septic shock, bacterial meningoencephalitis, and intracranial haemorrhage.
Among the multiresistant microorganisms are methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii.14 Enterobacter aerogenes, Escherichia coli, and Klebsiella pneumoniae are isolated opportunistic gram-negative microorganisms that cause infections provoked by endogenous or exogenous factors, and weaken the patient. Meanwhile, Enterobacter cloacae is a microorganism that causes bacterial translocation pneumonia, endogenous or external contamination, and was one of the microorganisms that presented resistance to all the antibiotics; the other was Pseudomonas aeruginosa.
It is essential that health professionals, who are in charge of the care of patients with endotracheal intubation and mechanical ventilation, carry out the monitoring and evaluation of alarm data that indicates a high probability of lung infection in the patient. In the present study, the Clinical Pulmonary Infection Score facilitated assessment and diagnosis of ventilator-associated pneumonia and served to define the coresponsibility of health professionals in the prevention, diagnosis, and treatment of VAP.
In this way, some recommendations were made to maintain patients with endotracheal intubation under favorable conditions. The first measure was to place the patients in the semi-Fowler's position between 30° and 45° in order to decrease aspiration and the presence of VAP.15
The second measure that was carried out to prevent VAP was hand hygiene based on the recommendations established for all health professionals who have contact with the patient: before direct contact with the patient, before performing a clean or aseptic task, after being exposed to body fluids, after patient contact, and after contact with the patient's environment.
The following recommendations were to maintain airway permeability and oral hygiene. The first was carried out by the aseptic technique of secretions aspiration through the closed system or open system. For the second procedure, 0.2% chlorhexidine gluconate solution was applied four times a day, as its use has been shown to reduce the VAP rate by 46%. It has also been reported that the procedure's adherence rate to achieve these results was 81%.16