Efficacy and safety of nasal high-flow oxygen in COPD patients.

BACKGROUND: Nasal high-flow oxygen therapy (HFOT) is a novel treatment option for patients suffering from acute or chronic respiratory failure. Aim of our study was to compare safety and efficacy of HFOT with those of conventional oxygen treatment (COT) in normo- and hypercapnic COPD patients. METHODS: A single cohort of 77 clinically stable hypoxemic patients with an indication for long-term oxygen treatment (LTOT) with or without hypercapnia successively received COT and HFOT for 60 min each, including oxygen adaption and separated by a 30 min washout phase. RESULTS: HFOT was well-tolerated in all patients. A significant decrease in PaCO2 was observed during oxygen adaption of HFOT, and increased PaO2 coincided with significantly increased SpO2 and decreased AaDO2 during both treatment phases. Even at a flow rate of 15 L/min, oxygen requirement delivered as air mixture by HFOT tended to be lower than that of COT (2.2 L/min). Not only was no increase in static or dynamic lung volumes observed during HFOT, but even was a significant reduction of residual lung volume measured in 36 patients (28%). CONCLUSIONS: Thus, short-term use of HFOT is safe in both normocapnic and hypercapnic COPD patients. Lower oxygen levels were effective in correcting hypoxemic respiratory failure and reducing hypercapnia, leading to a reduced amount of oxygen consumption. Long-term studies are needed to assess safety, tolerability, and clinical efficacy of HFOT. TRIAL REGISTRATION: ClinicalTrials.gov NCT01686893 13.09.2012 retrospectively registered (STIT-1) and NCT01693146 14.09.2012 retrospectively registered (STIT-2). Studies were approved by the local ethics committee (Ethikkommission der Medizinischen Universität Innsbruck, Studienkennzahl UN3547, Sitzungsnummer 274/4.19).

Influence of albumin dialysis on pharmacokinetics of amphotericin B colloidal dispersion and amphotericin B lipid complex.

Albumin dialysis (AD) is a therapeutic option in severe cholestatic liver failure. However, it can significantly enhance drug elimination. Pharmacokinetic data on antimicrobial agents--in particular on antimycotics--administered under this clinical condition are very sparse. Therefore, amphotericin B (AMB) plasma concentrations were measured in two critically ill patients who were treated with AD because of severe cholestatic liver failure and were prescribed lipid formulated AMB--either AMB colloidal dispersion (ABCD) or AMB lipid complex (ABLC)--for suspected invasive fungal infection. AD was performed with the molecular adsorbent recirculating system (MARS). Lipid-associated and liberated AMB were separately quantified on and off AD. The clearance of the liberated AMB fraction was not essentially affected (ABLC) or moderately enhanced during AD by a factor of 2.5 (ABCD). The clearance of the lipid-formulated fraction was increased by a factor of 4 during AD (ABCD) or was similar (ABLC) on and off AD. Despite the fact that there was a four-fold higher clearance of the lipid-formulated fraction of ABCD, the clinically relevant area under the concentration time curve of the liberated AMB fraction was only moderately changed (by 37% in ABCD, 70% in ABLC) during AD. Thus, the effect of AD on lipid formulated AMB appears to be moderate. A daily dose of 5 mg/kg will probably lead to adequate plasma levels in patients on AD.

Successful treatment of portopulmonary hypertension with the selective endothelin receptor antagonist Sitaxentan.

Portopulmonary hypertension (POPH) is a rare complication of portal hypertension. Prostanoids have been shown to be effective in the treatment of POPH and have been used as a bridge to liver transplantation. More recently, case series revealed beneficial effects of both the dual endothelin receptor antagonist bosentan and the phosphodiesterase-5 inhibitor sildenafil. The efficacy of sitaxentan, a selective endothelin receptor A (ERA) antagonist in the reversal of POPH, is still unclear. We report a case of POPH that was successfully treated with oral sitaxentan. Haemodynamic and symptomatic improvements were maintained after a 12-week long-term treatment period. Additionally, hepatic vein pressure gradient significantly decreased from 12 mmHg to 8 mm after treatment with sitaxentan. This is the first reported case of a successful therapy with a selective ERA antagonist in a patient suffering from POPH. Oral sitaxentan therapy might be a promising new option for patients suffering from POPH.

Sensory neuropeptides are potent chemoattractants for human basophils in vitro.

The sensory neuropeptides secretoneurin (SN) and substance P (SP) are involved in "neurogenic" inflammatory processes as they occur in bronchial asthma or allergic rhinitis. A possible interaction with basophils has not been reported to date. Basophils were isolated from healthy donors by magnetic cell sorting technique and migration was explored using Boyden microchemotaxis chambers. SN [10(-8)M] and SP [10(-6) to 10(-8)M] proved to be chemoattractants equally potent to FMLP [10(-8)M] or LPS [10 pg/ml]. Specific anti-SN antibodies and a trypsinization preparation of SN were used to determine the specificity of the SN effect on basophils. The preincubation of basophils with neurokinin-1 (NK-1) or -2 (NK-2) receptor antagonists revealed the SP effect to act via NK-1 receptors in basophils. In addition, we were able to show phosphodiesterases and phosphoinositide-3 kinases to be engaged in the downstream signalling pathway. Our observations reveal for the first time a link between basophils, which are engaged in allergic processes, and the neuropeptides SN and SP. Furthermore, our data might suggest phosphodiesterases or phosphoinositide-3 kinases to be new therapeutic targets for the treatment of allergic diseases such as asthma or allergic rhinitis.

Pulmonary epithelial lining fluid concentrations after use of systemic amphotericin B lipid formulations.

Amphotericin B (AMB) concentrations were determined in pulmonary epithelial lining fluid (ELF) of 44 critically ill patients, who were receiving treatment with liposomal AMB (LAMB) (n = 11), AMB colloidal dispersion (ABCD) (n = 28), or AMB lipid complex (ABLC) (n = 5). Mean AMB levels (+/- standard errors of the means) in ELF amounted to 1.60 +/- 0.58, 0.38 +/- 0.07, and 1.29 +/- 0.71 microg/ml in LAMB-, ABCD-, and ABLC-treated patients, respectively (differences are not significant).

Amphotericin B tissue distribution in autopsy material after treatment with liposomal amphotericin B and amphotericin B colloidal dispersion.

OBJECTIVES: Tissue concentrations of amphotericin B were determined in autopsy material of patients who had been treated with liposomal amphotericin B or amphotericin B colloidal dispersion (colloidal amphotericin B) for suspected or proven invasive fungal infection. PATIENTS AND METHODS: Amphotericin B tissue levels were measured in liver, spleen, lung, kidney, and myocardial and brain tissue of 20 patients who had been treated with lipid-formulated amphotericin B, before they died from multi-organ failure. Seven patients had been treated with liposomal amphotericin B (AmBisome) and thirteen with colloidal amphotericin B (Amphocil). Tissue samples were obtained during routine autopsy, homogenized and extracted with methanol. Amphotericin B concentrations were measured using HPLC after purification by solid phase extraction. RESULTS: The highest amphotericin B levels were found in liver and spleen, followed by kidney, lung, myocardium and brain. In the lung higher amphotericin B concentrations were found after treatment with amphotericin B colloidal dispersion than after therapy with liposomal amphotericin B. CONCLUSIONS: The choice of lipid formulation may influence amphotericin B penetration into the lung.

Pharmacokinetics of liposomal amphotericin B during extracorporeal albumin dialysis.

Extracorporeal blood purification techniques such as hemofiltration or albumin dialysis can exert a significant, but not easily predictable influence on plasma pharmacokinetics of antimicrobial agents. The effect of albumin dialysis on the pharmacokinetics of liposomal amphotericin B (AMB) and other lipid-formulated drugs has not been investigated so far. Therefore, plasma concentrations of liberated and liposomal AMB were measured in a patient, who obtained liposomal AMB for suspected invasive mycosis and required albumin dialysis because of cholestatic liver failure caused by graft versus host disease after bone marrow transplantation. Liberated and liposomal AMB were separated by solid phase extraction and measured by high performance liquid chromatography. No excessive AMB elimination took place during albumin dialysis. Plasma levels of liposomal AMB exceeded those of liberated AMB. Pharmacokinetic data were comparable to those obtained previously in patients on hemofiltration and in critically ill patients without extracorporeal blood purification.