Health care

Study was conducted at a university-affiliated, urban teaching hospital, Barnes-Jewish Hospital (1,400 beds). During a 20-month period (ie, February 2000 to October 2001), all patients requiring admission to the medical ICU (19 beds) for 48 h were eligible for this investigation. This inclusion criterion was prospectively selected to minimize the enrollment of patients with rapidly fatal illnesses and self-limited conditions not requiring more prolonged intensive care. Patients were excluded from this investigation if they had transferred from another hospital, if they had undergone a bone marrow transplant, or if they had been temporally transferred to the medical unit from another ICU due to staffing issues. The medical ICU is a closed unit with a multidisciplinary team providing patient care under the direction of attending physicians who are board-certified in critical care medicine.

For all study patients, the following characteristics were prospectively recorded by one of the investigators: age; gender; race; severity of illness based on APACHE (acute physiology and chronic health evaluation) II scores; and the presence of congestive heart failure, COPD, underlying malignancy, recent chemotherapy, seropositivity for HIV, diabetes mellitus, chronic renal insufficiency, cirrhosis, and solid organ transplantation. Specific processes of medical care examined during patients’ intensive care stay included the following: administration of antacids, sucralfate, histamine type-2 receptor antagonists, or corticosteroids; the number of central venous catheters placed; enteral nutrition; mechanical ventilation; the need for reintubation; the placement of a tracheostomy; surgery prior to ICU admission; the use of vasopressors; and the adequacy of the initially prescribed antibiotics for microbiologically confirmed infections. Infection variables also were examined, including leukocytosis, the development of new radiographic lung infiltrates, the presence of purulent sputum, temperature > 38.3°C, the presence of severe sepsis, the presence of Clostridium difficile infection, bloodstream infection Sildenafil citrate Australia , ventilator-associated pneumonia, hospital- acquired pneumonia in patients not requiring mechanical ventilation, tracheobronchitis, urinary tract infection, skin and soft-tissue infection, and community-acquired pneumonia; colonization with vancomycin-resistant enterococci; and the presence of multiple microbiologically confirmed infections.

Measures

The following variables were measured in each patient immediately before starting oxygen administration and during the oxygen treatment (at 20 min): PEFR, respiratory rate, heart rate, and arterial blood gases. At baseline, we also assessed the presence of accessory muscle Canadian health&Care Mall store use, dyspnea, and wheezing. PEFR was measured with a mini-Wright peak flowmeter (Clement Clarke; Harlow, UK). The highest of three values was recorded.

Heart rate was measured from continuous ECG. Accessory muscle use was defined as visible retraction of the sternocleidomastoid muscles. Dyspnea was defined as the patient’s own assessment of breathlessness. Wheezing was defined as musical or whistling breath sounds heard with a stethoscope during expiration. These clinical factors were graded in a scale from 0 to 3, in which 0 denoted absent, 1 indicated mild, 2 indicated moderate, and 3 indicated severe.

Arterial blood samples were obtained via puncture of the radial artery; and pH, Pao₂, and PaCo₂ were measured with a blood gas analyzer using routine techniques (ABL 500 system; Radiometer America; Westlake, OH). Arterial saturation (pulse oximetric saturation [Spo₂]) was monitored during oxygen administration by pulse oximetry with a finger oximeter (Nellcor N-180; Nellcor; Hayward, CA). Primary outcome measure was Paco₂ (difference between the two groups and variation from baseline) at the end of oxygen administration.

Secondary outcomes variables were pH, PEFR, Pao₂, heart rate, and respiratory rate (differences between groups and variation from baseline) at the end point. Patients unable to maintain a Spo₂ > 90% and/or presented clinical deterioration during the oxygen protocol were excluded and received inhaled bronchodi-lators and systemic corticosteroids.