Research
Lung Function and Organ Dysfunctions in 178 Patients Requiring Mechanical Ventilation During The 2009 Influenza A (H1N1) Pandemic
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* Corresponding author: Fernando G Ríos fernandrios@gmail.com
1 Sociedad Argentina de Terapia Intensiva (SATI), The Registry of the Argentinian Society of Intensive Care, Niceto Vega 4617, (C1414BEA) Ciudad de Buenos Aires, Argentina
2 Department Intensive Care, Clínica Olivos, Maipú 1660, (B1602ABQ), Vicente López, Buenos Aires, Argentina
3 Department Intensive Care, CEMIC, Av. Las Heras 2900, (C1425AUM), Ciudad de Buenos Aires, Argentina
4 Department of Adult Intensive Care, Hospital Nacional Alejandro Posadas, Marconi e Illia s/n, (B1706), El Palomar, Buenos Aires, Argentina
5 Department Intensive Care, Hospital General de Agudos Velez Sarsfield, Calderón de la Barca 1550, (C1407AHH), Ciudad de Buenos Aires, Argentina
6 Department Critical Care, Hospital Britanico, Perdriel 74, (C1280AEB) Ciudad de Buenos Aires, Argentina
7 Department Intensive care, Hospital Lopez Lima, Gelonch 721, (R8332HLH) Gral. Roca, Río Negro, Argentina
8 Department Critical care, Hospital Universitario Austral, Juan D. Perón 1500, (B1629ODT), Pilar, Buenos Aires, Argentina
9 Department Intensive Care, Hospital General de Agudos "Donación Francisco Santojanni", Pilar 950, (C1408INH), Ciudad de Buenos Aires, Argentina
10 Intensive Care Unit, Sanatorio de Los Arcos, Av. Juan B Justo 909, (C1425FSD), Ciudad de Buenos Aires, Argentina
11 Critical Care Unit, Sanatorio Juncal, Av Almirante Brown 2779, (B1832) Temperley, Buenos Aires, Argentina
12 Department Intensive Care, Hospital Bernardino Rivadavia, Av Las Heras 267, (C1425ASQ) Ciudad de Buenos Aires, Argentina
13 Intensive Care Unit, Clínica de Especialidades, Corrientes 733, (X5901ACG), Villa María, Córdoba, Argentina
14 Department Critical Care, Hospital General de Agudos, Juan A Fernández, Av Cervino 3356, (C1425AGP), Ciudad de Buenos Aires, Argentina
15 Department Intensive Care, Hospital Lagomaggiore, Gordillo s/n, (5500), Mendoza, Argentina
16 Department Intensive Care, Hospital Aleman, Av. Pueyrredón 1640, (C1118AAT), Ciudad de Buenos Aires, Argentina
17 Department Intensive Care, Hospital Interzonal Guemes, Av. 2° Rivadavia 15.000, (B1404), Haedo, Buenos Aires, Argentina
18 Department Intensive Care, Hospital Privado de la Comunidad, Córdoba 4545, (B7602CBM) Mar del Plata, Argentina
19 Intensive Care Unit, Hospital Universidad Abierta Interamericana, Portela 2975, (C1069AAB), Ciudad de Buenos Aires, Argentina
20 Intensive Care Unit, Sanatorio San Lucas, Belgrano 363, (B1642), San Isidro, Buenos Aires, Argentina
21 Department Intensive Care, Hospital Interzonal General San Martin, Calle 1 n 1791, (B1900) La Plata, Buenos Aires, Argentina
Critical Care 2011, 15:R201 doi:10.1186/cc10369
Published: 17 August 2011Abstract
Introduction
Most cases of the 2009 influenza A (H1N1) infection are self-limited, but occasionally the disease evolves to a severe condition needing hospitalization. Here we describe the evolution of the respiratory compromise, ventilatory management and laboratory variables of patients with diffuse viral pneumonitis caused by pandemic 2009 influenza A (H1N1) admitted to the ICU.
Method
This was a multicenter, prospective inception cohort study including adult patients with acute respiratory failure requiring mechanical ventilation (MV) admitted to 20 ICUs in Argentina between June and September of 2009 during the influenza A (H1N1) pandemic. In a standard case-report form, we collected epidemiological characteristics, results of real-time reverse-transcriptase--polymerase-chain-reaction viral diagnostic tests, oxygenation variables, acid-base status, respiratory mechanics, ventilation management and laboratory tests. Variables were recorded on ICU admission and at days 3, 7 and 10.
Results
During the study period 178 patients with diffuse viral pneumonitis requiring MV were admitted. They were 44 ± 15 years of age, with Acute Physiology And Chronic Health Evaluation II (APACHE II) scores of 18 ± 7, and most frequent comorbidities were obesity (26%), previous respiratory disease (24%) and immunosuppression (16%). Non-invasive ventilation (NIV) was applied in 49 (28%) patients on admission, but 94% were later intubated.
Acute respiratory distress syndrome (ARDS) was present throughout the entire ICU stay in the whole group (mean PaO2/FIO2 170 ± 25). Tidal-volumes used were 7.8 to 8.1 ml/kg (ideal body weight), plateau pressures always remained < 30 cmH2O, without differences between survivors and non-survivors; and mean positive end-expiratory pressure (PEEP) levels used were between 8 to 12 cm H2O. Rescue therapies, like recruitment maneuvers (8 to 35%), prone positioning (12 to 24%) and tracheal gas insufflation (3%) were frequently applied. At all time points, pH, platelet count, lactate dehydrogenase assay (LDH) and Sequential Organ Failure Assessment (SOFA) differed significantly between survivors and non-survivors. Lack of recovery of platelet count and persistence of leukocytosis were characteristic of non-survivors. Mortality was high (46%); and length of MV was 10 (6 to 17) days.
Conclusions
These patients had severe, hypoxemic respiratory failure compatible with ARDS that persisted over time, frequently requiring rescue therapies to support oxygenation. NIV use is not warranted, given its high failure rate. Death and evolution to prolonged mechanical ventilation were common outcomes. Persistence of thrombocytopenia, acidosis and leukocytosis, and high LDH levels found in non-survivors during the course of the disease might be novel prognostic findings.