Hamad Azam

ALVEOLAR–ARTERIAL OXYGEN GRADIENT, PNEUMONIA SEVERITY INDEX AND OUTCOMES IN PATIENTS HOSPITALIZED WITH COMMUNITY ACQUIRED PNEUMONIA

1 The alveolar–arterial oxygen gradient (ΔA–a) provides a useful assessment of ventilation/perfusion (V/Q) abnormalities. The objectives of the present study were to: (i) examine the correlation between the ΔA–a and the pneumonia severity index (PSI); and (ii) determine whether these measures were comparable in predicting clinical outcomes. 2 The present study was conducted at a 750‐bed teaching hospital. It examined a retrospective cohort of 255 patients with community acquired pneumonia (CAP) over a 2 year period. Association between the CAP and ΔA–a was investigated by regression models and correlation, as well as two logistic models for subjects bifurcated by low‐risk/moderate‐to‐high risk. The decision levels (DL) for both PSI and ΔA–a were then compared as predictors of both length of stay (LOS) and survival. 3 The correlation between PSI and ΔA–a was strong (ρ = 0.76; P < 0.0001) and was best modelled by a curvilinear relationship. Both logistic models indicated a strong association (P < 0.001) between ΔA–a and PSI and yielded an optimal DL for the ΔA–a of < 89 mmHg. Inter‐test agreement of ΔA–a with PSI was 76.9% (κ = 0.60; 95% confidence interval 0.47–0.72; P < 0.0001). At < 89 mmHg, the odds ratios for LOS were similar to those at PSI = 90 in predicting LOS in the range 3–7 days, inclusive. There was no significant difference in the ability of ΔA–a and PSI to predict survival for either the low‐ or high‐risk group (P = 0.363 and P = 0.951, respectively). 4 The ΔA–a correlates well with PSI and performs comparably in predicting two major outcomes in subjects hospitalized with CAP.

Frequency of hypoxic events in patients on a mechanical ventilator.

Background: Mechanical ventilation is an important tool in the management of respiratory failure in the critically ill patient. Although mechanical ventilation can be a life-saving intervention, it is also known to carry several side-effects and risks. Adequate oxygenation is one of the primary goals of mechanical ventilation. However, while on mechanical ventilation, patients frequently experience hypoxic events resulting from various causes, which need to be properly evaluated and treated. Materials and Methods: Data were obtained by prospectively reviewing all intensive care admissions during the period from March 2009 to March 2010 at a 651-bed urban medical center. Patients who developed hypoxemia (oxygen saturation ≤88% and a PaO2≤60 torrs) while on mechanical ventilation were investigated for the cause of hypoxic event. Results: During the study period, 955 patients required mechanical ventilation from which 79 developed acute hypoxia. The causes of acute hypoxia in decreasing order of occurrences were pulmonary edema, atelectasis, pneumothorax, pneumonia, ARDS, endotracheal tube malfunction, airway bleeding, and pulmonary embolism. Conclusions: Appropriate evaluation of all hypoxic events must begin at the bedside. A step-by-step approach must include a thorough physical examination. Evaluation of the endotracheal tube can immediately reveal dislodgement, bleeding, and secretions. Correlation of physical examination findings with those on chest radiograph is essential. Each hypoxic event requires a different intervention depending on its etiology. Instead of simply increasing the fraction of oxygen in the inspired air to overcome hypoxia, a concerted effort in appropriate problem solving can reduce the likelihood of an incorrect diagnosis and management response.

Pulmonary Hydatid Cyst with Complicating Aspergillus Infection Presenting as a Refractory Lung Abscess

Background Hydatid disease is rare in the United States. Rarely the hydatid cyst can become infected with mycotic organisms, such as Aspergillus. We describe a young male who presents with clinical features of suppurative lung abscess whose workup diagnosed hydatid cyst complicated by Aspergillus co-infection. Case presentation A 27-year-old Peruvian male was hospitalized because of fever, chills, and productive cough of three months’ duration. Clinical features were consistent with a suppurative lung abscess. Significant findings included leukocytosis with eosinophilia and a chest x-ray showing a large lingular lobe thick walled cavity with a wavy irregular fluid level. The patient ultimately underwent surgical resection of the lingular lobe. Examination of the surgical specimen revealed the cavity to be a hydatid cyst. Histologic examination of the cyst wall showed intense inflammation and several septate hyphae of Aspergillus species. The patient recovered fully and has remained in good health. Conclusion A thick-walled cavity and a wavy meniscus constitute unusual features for an ordinary pyogenic lung abscess and suggests other possibilities. Endogenous cases of hydatid disease are uncommon in the United States, with the majority of cases occurring in immigrants. There are few published case reports describing incidental findings of Aspergillus in a hydatid cyst. The rare occurrence of such a condition can lead to a delay in diagnosis and treatment.