Positron emission tomography demonstrates radiation-induced changes to nonirradiated lungs in lung cancer patients treated with radiation and chemotherapy.

STUDY OBJECTIVES: To determine whether acute changes in shielded lungs can be detected by positron emission tomography (PET) after radiation therapy. DESIGN: Retrospective cohort study. SETTING: University-affiliated medical center. PATIENTS: Sixteen patients undergoing radiation therapy for lung cancer who had PET scans after receiving treatment. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Thirteen of 16 patients (81.2%) showed increased (18)fluoro-2-deoxyglucose uptake in shielded nonirradiated lung in the following four distinct patterns: (1) contralateral peripheral pleural uptake in 5 of 16 patients (31.2%); (2) ipsilateral peripheral pleural uptake in 5 of 16 patients (31.2%); (3) bilateral peripheral pleural uptake in 1 of 16 patients (6.2%); and (4) bilateral diffuse background uptake in 1 of 16 patients (6.2%). This last patient developed clinically evident radiation pneumonitis. CONCLUSIONS: Increased lung metabolic activity can be demonstrated in the nonirradiated lung in patients who have undergone radiation therapy for lung cancer and can be detected by PET scanning. PET scanning of lungs in irradiated patients may provide an early demonstrable barometer of pulmonary toxicity. If verified, this imaging tool could prove to be useful in monitoring patients receiving radiation therapy for thoracic malignancies and may have predictive value for subsequent fibrosis. PET scanning may also be an important tool in future studies to further elucidate the pathogenetic mechanism of radiation-induced lung injury.

Acute lung injury induced by arsenic trioxide in a patient with refractory myelodysplastic syndrome.

Arsenic trioxide has been used successfully for the treatment of refractory acute promyelocytic leukemia and has shown promise in the treatment of myelodysplastic syndrome (MDS), although it is not a labeled indication. Retinoic acid syndrome is manifested by fever, dyspnea, peripheral edema, pulmonary infiltrates, and pleural and/or pericardial effusions and is typically seen in conjunction with all- trans retinoic acid therapy of acute promyelocytic leukemia. We report a case of acute lung injury and a retinoic acid syndrome-like illness in a patient who received arsenic for MDS. To our knowledge, this is the first such report, and clinicians should be aware of this potentially life-threatening complication of arsenic trioxide treatment in patients with MDS.

The effect of continuous positive airway pressure on glucose control in diabetic patients with severe obstructive sleep apnea.

Obstructive sleep apnea (OSA) is independently associated with glucose intolerance and insulin resistance, and recent studies have shown that continuous positive airway pressure (CPAP) improves insulin sensitivity. The objective of this study was to describe the change in glycosylated hemoglobin (HbA1c) after treatment with CPAP in patients with type 2 diabetes mellitus and OSA. To test this hypothesis, we performed a retrospective analysis of 38 patients seen in the sleep clinic of an urban public teaching hospital. All patients had OSA and type 2 diabetes mellitus, and their diabetic medication regimen had remained unchanged during the period of CPAP therapy. Sixty-one percent were men, body mass index was 42+/-9.5 kg/m(2), and the Apnea-Hypopnea Index was 53+/-36 per hour. HbA1c before therapy with CPAP was 7.8+/-1.4% and decreased to 7.3+/-1.3% after 134+/-119 days of therapy (p<0.001). Treatment with CPAP leads to a clinically significant drop in HbA1c in patients with type 2 diabetes mellitus and severe OSA.

Torsade de pointes associated with the administration of intravenous haloperidol:a review of the literature and practical guidelines for use.

Haloperidol is the most commonly used medication for the treatment of delirium and psychosis in the critically ill patient. Whilst generally considered to be safe, haloperidol has been associated with a number of important cardiovascular side effects. The major toxicities include hypotension, cardiac arrhythmias and prolongation of the corrected QT (QTc) interval. In particular, torsade de pointes, a polymorphic ventricular tachyarrhythmia, has been associated with both intravenous and oral haloperidol administration. The management of torsade de pointes consists of discontinuation of the possible offending agent(s), correction of electrolyte abnormalities, administration of magnesium sulfate and, if necessary, overdrive pacing. Although clinicians should be aware of this potentially lethal complication of intravenous haloperidol therapy, it should not deter clinicians from using intravenous haloperidol to treat acute agitation in the critically ill patient with a normal QTc.

Impact of adherence with positive airway pressure therapy on hypercapnia in obstructive sleep apnea.

BACKGROUND: Daytime hypercapnia is common in morbidly obese patients with obstructive sleep apnea and is associated with serious complications. Our objective was to quantify the effect of adherence with positive airway pressure on hypercapnia and hypoxia in these patients. METHODS: We performed a retrospective cohort study of 75 patients using a multivariable general linear model analysis to identify variables that predicted changes in PaCO2 and PaO2 after therapy. Bootstrap resampling methods were used to calculate confidence intervals for the effects of significant predictors and to internally validate the predictive models. RESULTS: The variables that predicted the change in PaCO2 were average daily hours of positive pressure therapy, FEV1 percentage of predicted, and baseline PaCO2 (model R(2) = 0.70). The PaCO2 dropped 1.84 mm Hg per hour of adherence and plateaued at 7 hours of average daily use. The PaO2 improved by approximately 3 mm Hg per hour of adherence and plateaued after 4.5 hours of therapy (model R2 = 0.48). Patients who used therapy for more than 4.5 hours per day experienced significant improvements in PaCO2 and PaO2 compared with less-adherent patients (APaCO2 7.7+/-5 vs 2.4+/-4 mm Hg, p < .001; delta PaO2 9.2+/-11 vs 1.8+/-9 mm Hg, p < .001). For adherent patients, the need for daytime home oxygen therapy decreased from 30% to 6% (p = .02). CONCLUSION: In hypercapnic patients with obstructive sleep apnea, adherence with positive airway pressure is an important modifiable predictor of improvements in PaCO2 and PaO2, and its benefit plateaus between 5 and 7 hours of daily therapy.

Metal fume fever presenting as aseptic meningitis with pericarditis, pleuritis and pneumonitis.

BACKGROUND: Metal fume fever (MFF) is a well-known complication of zinc oxide fume inhalation. Prompt recognition of this condition is essential for the proper medical management of this self-limited disease. AIM: To present a unique and unusual case of MFF. RESULTS: Our patient is a 25-year-old male welder who had MFF and presented with aseptic meningitis with pericarditis, pleuritis and pneumonitis. To our knowledge, this is the first case of MMF presenting with these signs and symptoms. CONCLUSIONS: MFF can present with a systemic inflammatory response causing a multi-organ serositis. Our case highlights the utmost importance of obtaining an occupational history on all our patients, even if they are critically ill.

Torsade de pointes associated with the administration of intravenous haloperidol.

Torsade de pointes is a malignant dysrhythmia that has been reported in a variety of clinical settings and associated with several pharmacologic agents. Patients with a prolonged QTc for heart rate are at higher risk for the development of this arrhythmia. We review the literature supporting the relationship of haloperidol to the development of this malignant dysrhythmia. Clinicians in the critical care setting should be aware of potentially lethal drug-induced ventricular tachydysrhythmias such as torsade de pointes.