Showing papers by "Andrea De Gaetano published in 2014"

Nasal high-flow versus Venturi mask oxygen therapy after extubation. Effects on oxygenation, comfort, and clinical outcome

Abstract: Rationale Oxygen is commonly administered after extubation. Although several devices are available, data about their clinical efficacy are scarce. Objectives To compare the effects of the Venturi mask and the nasal high-flow (NHF) therapy on PaO2/FiO2SET ratio after extubation. Secondary endpoints were to assess effects on patient discomfort, adverse events, and clinical outcomes. Methods Randomized, controlled, open-label trial on 105 patients with a PaO2/FiO2 ratio less than or equal to 300 immediately before extubation. The Venturi mask (n = 52) or NHF (n = 53) were applied for 48 hours postextubation. Measurements and main results PaO2/FiO2SET, patient discomfort caused by the interface and by symptoms of airways dryness (on a 10-point numerical rating scale), interface displacements, oxygen desaturations, need for ventilator support, and reintubation were assessed up to 48 hours after extubation. From the 24th hour, PaO2/FiO2SET was higher with the NHF (287 ± 74 vs. 247 ± 81 at 24 h; P = 0.03). Discomfort related both to the interface and to airways dryness was better with NHF (respectively, 2.6 ± 2.2 vs. 5.1 ± 3.3 at 24 h, P = 0.006; 2.2 ± 1.8 vs. 3.7 ± 2.4 at 24 h, P = 0.002). Fewer patients had interface displacements (32% vs. 56%; P = 0.01), oxygen desaturations (40% vs. 75%; P Conclusions Compared with the Venturi mask, NHF results in better oxygenation for the same set FiO2 after extubation. Use of NHF is associated with better comfort, fewer desaturations and interface displacements, and a lower reintubation rate. Clinical trial registered with www.clinicaltrials.gov (NCT 01575353).

Mathematical modeling of renal tubular glucose absorption after glucose load.

Abstract: A partial differential Progressive Tubular Reabsorption (PTR) model, describing renal tubular glucose reabsorption and urinary glucose excretion following a glucose load perturbation, is proposed and fitted to experimental data from five subjects. For each subject the Glomerular Filtration Rate was estimated and both blood and urine glucose were sampled following an Intra-Venous glucose bolus. The PTR model was compared with a model representing the conventional Renal Threshold Hypothesis (RTH). A delay bladder compartment was introduced in both formulations. For the RTH model, the average threshold for glycosuria varied between 9.90±4.50 mmol/L and 10.63±3.64 mmol/L (mean ± Standard Deviation) under different hypotheses; the corresponding average maximal transport rates varied between 0.48±0.45 mmol/min (86.29±81.22 mg/min) and 0.50±0.42 mmol/min (90.62±76.15 mg/min). For the PTR Model, the average maximal transports rates varied between 0.61±0.52 mmol/min (109.57±93.77 mg/min) and 0.83±0.95 mmol/min (150.13±171.85 mg/min). The time spent by glucose inside the tubules before entering the bladder compartment varied between 1.66±0.73 min and 2.45±1.01 min. The PTR model proved much better than RTH at fitting observations, by correctly reproducing the delay of variations of glycosuria with respect to the driving glycemia, and by predicting non-zero urinary glucose elimination at low glycemias. This model is useful when studying both transients and steady-state glucose elimination as well as in assessing drug-related changes in renal glucose excretion.

Simulation of insulin regimen and glucose profiles in Type 1 Diabetic Patient

Abstract: A composite model, describing the glucose/insulin dynamics following daily food administration and insulin injections in Type 1 Diabetes Mellitus patients is presented. Three daily meals have been simulated, food intake representing four different types of foodstuffs, along with three rapid-acting insulin injections and one long-acting insulin injection. Three different scenarios (depending on whether food intake and/or administration times were fixed or random) were hypothesized: simulations show a very realistic time-course for both glucose and insulin dynamics over long (20 days) and short (one day) time periods.

DDE Model-Based Control of Glycemia via Sub-cutaneous Insulin Administration

Abstract: Plasma glucose regulation is commonly attained in Type 1 Diabetes Mellitus (T1DM) patients, as well as in advanced Type 2 Diabetes Mellitus (T2DM), by means of Sub-Cutaneous (SC) insulin administration. In order to study this extremely common and relevant clinical problem from a theoretical point of view, a Delay Differential Equation (DDE) model of the glucose-insulin system has been considered. The model extends a previous DDE model, already used for glucose control, by endowing it with a SC Insulin compartment and by introducing modifications regarding insulin-independent glucose uptake and Hepatic Glucose Output (HGO). Pancreatic insulin release (non-negligible in T2DM) is considered, in order for the control method to address both T1DM and T2DM. The method of exact input/output feedback linearization and stabilization is used, to ensure the local convergence of the tracking error to zero. Numerical simulations show the effectiveness of the proposed approach.