Life‐threatening respiratory failure from H1N1 influenza 09  (human swine influenza)

Abstract

A 28-year-old obese woman (body mass index [BMI], 57 kg/m 2 ) presented to the emergency department (ED) with a history of 5 days of sore throat, lethargy and myalgias, and a clear chest x-ray, followed by 2 days of dyspnoea, productive cough, and pleuritic chest pain. She was febrile (40°C), and had tachypnoea (respiratory rate, 36 breaths/min) and hypoxia (oxygen saturation measured by pulse oximetry [SpO 2 ], 87% on 15 L/min oxygen via face mask). Her admission chest x-ray showed widespread alveolar infiltrates. She had a normal white cell count (WCC) of 6.3 10 9 /L, but an elevated serum C-reactive protein (CRP) level of 221 mg/L (reference ranges shown in Box 1). She was admitted to the intensive care unit (ICU) and, after a brief trial of noninvasive ventilation (NIV), was intubated and treated with mechanical ventilation (MV) with a fraction of inspired oxygen (FiO 2 ) of 1.0 and positive end-expiratory pressure (PEEP) of 20 cm H 2 O for the first 24 hours to maintain an SpO 2 > 89%. She was treated with inotropes for septic shock and with renal replacement therapy for acute renal failure. Therapy with oseltamivir in addition to empiric broad-spectrum antibiotics was commenced. Bacterial cultures of blood, urine and tracheal aspirate were negative. The result of a test for urine pneumococcal antigen was negative. The patient was successfully weaned from ventilatory support on Day 14. Patient 2A previously well 24-year-old man (BMI, 22 kg/m 2 ) was admitted to a regional hospital with a 1-week history of dry cough, fever, headache, abdominal pain, and vomiting. Thirty-six hours later, he was transferred to a metropolitan hospital because of worsening dyspnoea and hypoxia (SpO 2 , 88% on 15 L/min oxygen via face mask). He had tachycardia (110 beats/min), tachypnoea (respiratory rate, 34 breaths/min) and was febrile (39.9°C). He had a normal WCC (4.2 10 9 /L) but an elevated CRP level (256 mg/L).A chest x-ray showed unilateral lobar consolidation. He was transferred to the ICU and treated with oseltamivir, broad-spectrum antibiotics, and NIV with an FiO 2 of 1.0. After 96 hours, his hypoxia remained severe (partial pressure of arterial oxygen [PaO 2 ] to FiO 2 ratio, < 100), another chest x-ray showed bilateral alveolar infiltrates, and he was intubated and MV was commenced with an FiO 2 of 1.0 and high-level PEEP (20 cm H 2 O) for several days.Bacterial cultures and urine pneumococcal antigen test results were negative. Oseltamivir therapy was continued for 7 days, and MV for 15 days. Patient 3A 26-year-old obese man (BMI, > 40 kg/m 2 ) with a history of mild asthma presented after 2 days of nausea without vomiting, and no fever or cough. On the day of admission, he developed shortness of breath. He was found to be hypoxic (SpO 2 , 90% on an FiO 2 of 1.0) with bilateral pulmonary infiltrates showing on a chest x-ray. His WCC was 5.6 10 9 /L and CRP level was 137 mg/L. Therapy with broad-spectrum antibiotics and oseltamivir was commenced. He was intubated, and MV was commenced with an FiO 2 of > 0.6 and high-...

Hospitalised adult patients with pandemic (H1N1) 2009 influenza in Melbourne, Australia

“…Length of stay data were collected for total time in hospital as well as time spent in intensive care units (ICUs). Data for six patients in this series have been reported in an earlier brief communication 9 …”

Influenza and Endemic Viral Pneumonia

“…76 Most centers internationally ventilated 2009 H1N1 viral pneumonitis patients with low tidal ventilation (6 mL/kg of predicted body weight and plateau pressures <30 cm H 2 O) whenever possible, as this is what has been recommended for ARDS based on results of the ARDSNet trial. 46,69,70,[77][78][79] High levels of positive endexpiratory pressure (PEEP) were noted to be required to manage severe hypoxemia, with mean PEEP levels between 16 and 22 cm H 2 O reported in some studies. 25,38,39,49 Other modes of ventilation were also used, including airway pressure release ventilation and high-frequency oscillation; however, there are insufficient data to conclusively state whether these modes had any impact on outcomes.…”

Clinical Management of Pandemic 2009 Influenza A(H1N1) Infection

“…30 IMV, with a lung-protective ventilation strategy, is recommended as the initial approach for managing patients with pandemic A(H1N1) infection complicated by ARDS. 26,30 The recommendation is based on the ARDSNet trial demonstrating a relative risk reduction of mortality by 22% in patients with ARDS ventilated with the lower tidal volume (eg, goal of maximum tidal volume 6 mL/kg of predicted body weight with plateau pressures up to maximum 30 cm H 2 O). 32 Furthermore, it is prudent to adopt a conservative fl uid management approach for patients with ARDS/acute lung injury, as this has been shown to increase ventilator-free days and improve oxygenation when compared with a fl uid liberal strategy.…”