Pandemic 2009 influenza A in Argentina: a study of 337 patients on mechanical ventilation

Am J Respir Crit Care Med. 2010 Jul 1;182(1):41-8. doi: 10.1164/201001-0037OC. Epub 2010 Mar 4.

Abstract

Rationale: The rapid spread of the 2009 Influenza A (H1N1) around the world underscores the need for a better knowledge of epidemiology, clinical features, outcomes, and mortality predictors, especially in the most severe presentations.

Objectives: To describe these characteristics in patients with confirmed, probable, and suspected viral pneumonia caused by 2009 influenza A (H1N1) admitted to 35 intensive care units with acute respiratory failure requiring mechanical ventilation in Argentina, between June 3 and September 7.

Methods: Inception-cohort study including 337 consecutive adult patients. Data were collected in a form posted on the Argentinian Society of Intensive Care website.

Measurements and main results: Proportions of confirmed, probable, or suspected cases were 39%, 8%, and 53% and had similar outcomes. APACHE II was 18 +/- 7; age 47 +/- 17 years; 56% were male; and 64% had underlying conditions, with obesity (24%), chronic obstructive respiratory disease (18%), and immunosupression (15%) being the most common. Seven percent were pregnant. On admission, patients had severe hypoxemia (Pa(O(2))/Fi(O(2)) 140 [87-200]), extensive lung radiologic infiltrates (2.87 +/- 1.03 quadrants) and bacterial coinfection, (25%; mostly with Streptococcus pneumoniae). Use of adjuvants such as recruitment maneuvers (40%) and prone positioning (13%), and shock (72%) and acute kidney injury requiring hemodialysis (17%), were frequent. Mortality was 46%, and was similar across all ages. APACHE II, lowest Pa(O(2))/Fi(O(2)), shock, hemodialysis, prone positioning, and S. pneumoniae coinfection independently predicted death.

Conclusions: Patients with 2009 influenza A (H1N1) requiring mechanical ventilation were mostly middle-aged adults, often with comorbidities, and frequently developed severe acute respiratory distress syndrome and multiorgan failure requiring advanced organ support. Case fatality rate was accordingly high.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • APACHE
  • Adult
  • Argentina / epidemiology
  • Cohort Studies
  • Disease Outbreaks*
  • Female
  • Humans
  • Hypoxia / mortality
  • Influenza A Virus, H1N1 Subtype*
  • Influenza, Human / complications
  • Influenza, Human / mortality*
  • Influenza, Human / therapy
  • Male
  • Middle Aged
  • Pneumonia, Pneumococcal / complications
  • Pneumonia, Pneumococcal / mortality
  • Pregnancy
  • Respiration, Artificial*
  • Respiratory Distress Syndrome, Adult / etiology
  • Respiratory Distress Syndrome, Adult / mortality
  • Respiratory Distress Syndrome, Adult / therapy*