Carbonic anhydrase inhibitors in patients with respiratory failure and metabolic alkalosis: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Metabolic alkalosis is common in patients with respiratory failure and may delay weaning in mechanically ventilated patients. Carbonic anhydrase inhibitors block renal bicarbonate reabsorption, and thus reverse metabolic alkalosis. The objective of this systematic review is to assess the benefits and harms of carbonic anhydrase inhibitor therapy in patients with respiratory failure and metabolic alkalosis. METHODS: We searched the following electronic sources from inception to August 2017: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and SCOPUS. Randomized clinical trials were included if they assessed at least one of the following outcomes: mortality, duration of hospital stay, duration of mechanical ventilation, adverse events, and blood gas parameters. Teams of two review authors worked in an independent and duplicate manner to select eligible trials, extract data, and assess risk of bias of the included trials. We used meta-analysis to synthesize statistical data and then assessed the certainty of evidence using the GRADE methodology. RESULTS: Six eligible studies were identified with a total of 564 participants. The synthesized data did not exclude a reduction or an increase in mortality (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.57 to 1.56) or in duration of hospital stay (mean difference (MD) 0.42 days, 95% CI -4.82 to 5.66) with the use of carbonic anhydrase inhibitors. Carbonic anhydrase inhibitor therapy resulted in a decrease in the duration of mechanical ventilation of 27 h (95% CI -50 to -4). Also, it resulted in an increase in PaO2 (MD 11.37 mmHg, 95% CI 4.18 to 18.56) and a decrease in PaCO2 (MD -4.98 mmHg, 95% CI -9.66, -0.3), serum bicarbonate (MD -5.03 meq/L, 95% CI -6.52 to -3.54), and pH (MD -0.04, 95% CI -0.07 to -0.01). There was an increased risk of adverse events in the carbonic anhydrase inhibitor group (RR 1.71, 95% CI 0.98 to 2.99). Certainty of evidence was judged to be low for most outcomes. CONCLUSION: In patients with respiratory failure and metabolic alkalosis, carbonic anhydrase inhibitor therapy may have favorable effects on blood gas parameters. In mechanically ventilated patients, carbonic anhydrase inhibitor therapy may decrease the duration of mechanical ventilation. A major limitation of this finding was that only two trials assessed this clinically important outcome.

Ventilator auto-cycling from cardiogenic oscillations: case report and review of literature.

BACKGROUND: Brain death is the total loss of all brain and brain stem functions, and its diagnosis is often confirmed by an apnoea test, which relies on disconnecting the patient from the ventilator. Auto-triggering or auto-cycling is defined as a ventilator being triggered in the absence of patient effort, intrinsic respiratory drive or inspiratory muscle activity. Ventilator auto-triggering could delay the diagnosis of brain death leading to unnecessary admission for the patient and false hopes of recovery for the family. METHODS: We report a case of ventilator auto-triggering associated with cardiogenic oscillations in a female patient. RESULTS: We confirmed the finding of ventilator auto-triggering by changing the patient's position and reassessing the triggering thresholds. Brain death was then confirmed by apnoea test. CONCLUSION: This case is presented to arouse the awareness of the medical staff and nurses to this phenomenon, which can mimic an intrinsic respiratory effort in patients allegedly diagnosed with brain death. Along with this case report, we review the English language publications for similar cases.

Primary dedifferentiated chondrosarcoma of the lung.

Extraskeletal dedifferentiated chondrosarcomas (DC) are uncommon tumors that predominantly occur in the head and neck. Herein, we describe a case of pulmonary DC detected in a patient with systemic sclerosis and presenting with a symptomatic large pleural effusion and a pulmonary lobar consolidation on chest imaging. To the best of our knowledge, this is the first report of pulmonary chondrosarcoma involving the pleura and occurring in association with systemic sclerosis. Moreover, this is the second report of a dedifferentiated variant among all reported cases of primary lung chondrosarcoma.

COPD updates: what's new in pathophysiology and management?

The historic perspective that used to define chronic obstructive pulmonary disease has changed. As reviewed in this article, it is based on a better understanding of the underlying inflammatory airflow obstruction and a multidimensional classification, which mostly targets a subgroup called 'frequent exacerbators'. Clinical and radioimaging predictors are the stamina for an aggressive therapeutic approach. A simplified explanation of the updated Global Initiative for Obstructive Lung Disease guidelines will ease the burden of treatment selection.

Fatal bilateral pneumothoraces complicating dyskeratosis congenita: a case report.

INTRODUCTION: Dyskeratosis congenita is a rare genodermatosis, characterized by a triad of reticular skin pigmentation, nail dystrophy and leukoplakia of mucous membranes. It is also associated with a variety of non-cutaneous abnormalities such as bone marrow failure, malignancy and pulmonary complications. Among its wide range of clinical manifestations, fatal pneumothorax has rarely been reported. CASE PRESENTATION: We report the case of a 31-year-old Lebanese woman with dyskeratosis congenita who succumbed to devastating bilateral pneumothoraces. CONCLUSION: Careful surveillance of patients with dyskeratosis congenita is required as incipient respiratory failure due to pneumothorax may be successfully treated if detected at an early stage.