Francisco Arancibia

Influenza A pandemics: Clinical and organizational aspects: The experience in Chile

Recently, the World Health Organization declared a pandemic mediated by the novel A H1N1 influenza virus. Soon after the first report from Mexico, the disease arrived in Chile, where it spread quickly from south to north, mimicking cold weather progression through the country. Between May and September 2009, 366,624 cases of H1N1 were reported; 12,248 were confirmed by real-time reverse-transcription polymerase chain reaction and 1562 were hospitalized. One hundred thirty-two deaths were attributable to the infection, creating a death rate of 0.78 per 100,000 inhabitants. Common comorbidities were present in 59%, including obesity, chronic obstructive pulmonary disease, hypertension, type II diabetes, and congestive heart failure. Nine percent were pregnant. Severe disease developed early; the median time to admittance was 5 days, and the most common clinical manifestations were cough, fever, dyspnea, and myalgia. Mean acute physiology and chronic health evaluation II and sequential organ failure assessment scores were 14 and 5, respectively. Highlighted laboratory data were lactate dehydrogenase and creatine kinase elevation, leukocytosis in 50%, elevated creatinine in a 25%, and thrombocytopenia in 20%. Severe respiratory failure requiring high-frequency oscillatory ventilation and extracorporeal membrane oxygenation as sophisticated modes of respiratory support was seen in 17%. Acute renal failure occurred in 25% of the intensive care unit patients, with death rates near 50%. Health systems reinforced outpatient guards with extra staff and extension of the duty schedules. Antivirals were supplied free for medically diagnosed cases. Admissions for severe cases were prioritized, reconverting hospital beds into advanced care ones; a central coordination station rationed their assignment. Recommendations for small hospitals include adding ventilators, using videoconferences, providing tutorial activity from experts, developing guidelines for disease management, and outlining criteria for transport.

Clinical characteristics and outcomes of patients with 2009 influenza A(H1N1) virus infection with respiratory failure requiring mechanical ventilation

PURPOSE The purpose of the study was to describe the clinical characteristics and outcomes of critically ill patients with 2009 influenza A(H1N1). METHODS An observational study of patients with confirmed or probable 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation was performed. RESULTS We studied 96 patients (mean age, 45 [14] years [mean, SD]; 44% female). Shock and acute respiratory distress syndrome were diagnosed during the first 72 hours of admission in 43% and 72% of patients, respectively. Noninvasive positive pressure ventilation was used in 45% of the patients, but failed in 77% of them. Bacterial pneumonia was diagnosed in 33% of cases, 8% during the first week (due to community-acquired microorganisms) and 25% after the first week (due to gram-negative bacilli and resistant gram-positive cocci). Intensive care unit mortality was 50%. Nonsurvivors differed from survivors in the prevalence of cardiovascular, respiratory, and hematologic failure on admission and late pneumonia. Reported causes of death were refractory hypoxia, multiorgan failure, and shock (50%, 38%, and 12% of all causes of death, respectively). CONCLUSIONS Patients with 2009 influenza A(H1N1) and respiratory failure requiring mechanical ventilation often present with clinical criteria of acute respiratory distress syndrome and shock. Bacterial pneumonia is a frequent complication. Mortality is high and is primarily due to refractory hypoxia.

Importance of Legionella pneumophila in the Etiology of Severe Community-Acquired Pneumonia in Santiago, Chile

BACKGROUND In US and European literature, Legionella pneumophila is reported as an important etiologic agent of severe community-acquired pneumonia (CAP), but in Chile this information is lacking. The aim of this study was to determine the incidence and identify predictors of severe CAP caused by L pneumophila in Santiago, Chile. METHODS A multicenter, prospective clinical study lasting 18 months was conducted; it included all adult patients with severe CAP admitted to the ICUs of four hospitals in Santiago. We excluded patients who were immunocompromised, had been hospitalized in the previous 4 weeks, or presented with another disease during their hospitalization. All data for the diagnosis of severe CAP were registered, and urinary antigens for L pneumophila serogroup 1 were determined. RESULTS A total of 104 patients with severe CAP were included (mean ± SD age, 58.3 ± 19.3 years; men, 64.4%; APACHE (Acute Physiology and Chronic Health Evaluation) II score, 16.7 ± 6.3; Sepsis-related Organ Failure Assessment score, 6.1 ± 3.2; Pitt Bacteremia Score, 3.4 ± 2.5; Pao2/Fio2, 170.8 ± 87.1). An etiologic agent was identified in 62 patients (59.6%), with the most frequent being Streptococcus pneumoniae (27 patients [26%]) and L pneumophila (nine patients [8.6%]). Logistic regression analysis showed that a plasma sodium level of ≤ 130 mEq/L was an independent predictor for L pneumophila severe CAP (OR, 11.3; 95% CI, 2.5-50.5; P = .002). Global mortality was 26% and 33% for L pneumophila. The Pitt bacteremia score and pneumonia score index were the best predictors of mortality. CONCLUSIONS We found that in Santiago, L pneumophila was second to S pneumoniae as the etiologic agent of severe CAP. Severe hyponatremia at admission appears to be an indicator for L pneumophila etiology in severe CAP.

Risk Factors for Drug-Resistant Cap in Immunocompetent Patients

Purpose of ReviewThe increase in drug-resistant community-acquired pneumonia (CAP) is an important problem all over the world. This article explores the current state of antimicrobial resistance of different bacteria that cause CAP and also assesses risk factors to identify those pathogens.Recent FindingsIn the last two decades, it has been documented that there is a significant increase in drug-resistant Streptococcus pneumoniae and other bacteria causing CAP. The most important risk factors are overuse of antibiotics, prior hospitalization, and lung comorbidities. The direct consequences can be severe, including prolonged stays in hospital, increased costs, and morbi-mortality. However, drug-resistant CAP declined after the introduction of the pneumococcal conjugate vaccine.SummaryThis review found an increase in resistance to the antibiotics used in CAP, and the risk factor can be used for identifying patients with drug-resistant CAP and initiate appropriate treatment. Judicious use of antibiotics and the development of effective new vaccines are needed.