PubMed Health⌕ Search

Biomedical subjects

N Patroniti

Publications and source records attributed to N Patroniti.

5 recordsLinked to original sources
PubMed2002

Intratracheal pulmonary ventilation keeps tracheal tubes clean without impairing mucociliary transport.

BACKGROUND: Intratracheal pulmonary ventilation (ITPV) is a form of tracheal gas insufflation through a reverse thrust catheter that facilitates expiration and enhances CO2 removal. Tracheas of sheep mechanically ventilated for 3 days with gas delivered through the reverse-thrust catheter remained free of secretions, without suctioning. It was hypothesized that: 1) The expiratory flow from the lungs, combined with continuous cephalad flow from the reverse-thrust catheter keeps endotracheal tubes clean; and 2) tracheal mucus velocity is not impaired by ITPV. METHODS: A model trachea connected to a test lung and to a ventilator, via an 8-mm endotracheal tube, was used. Inspiratory and expiratory peak flow velocities and the movement of mucus in the model trachea and in the endotracheal tube were measured during conventional mechanical ventilation and ITPV. Tracheal mucus velocity was measured radiographically, using tantalum discs as markers, in seven intubated sheep ventilated for one hour with volume-controlled ventilation, and with ITPV. One millilitre Evans Blue dye was introduced into the trachea, to visualize mucus transport into the endotracheal tube. RESULTS: Peak expiratory flow velocity exceeded peak inspiratory flow velocity by 100% during ITPV. During volume-controlled ventilation, flow velocities were equal. During ITPV, there was slow, then rapid cephalad movement of mucus in the model trachea, 0.5 cm distal to the tip of the endotracheal tube, the velocity increasing once mucus entered the endotracheal tube. During volume-controlled ventilation, no movement of mucus was found. Baseline tracheal mucus velocity was equal during volume-controlled ventilation and ITPV. Secretions stained with Evans Blue dye entered the endotracheal tube and were rapidly expelled from within the endotracheal tubes during ITPV; only traces of mucus were found in two sheep during volume-controlled ventilation. CONCLUSION: The enhanced expiratory flow during ITPV expels secretions from the endotracheal tube through entraining of mucus at the tip of the endotracheal tube. Tracheal mucus velocity is not influenced by ITPV.

Animals↗
PubMed2001

Computerised tomography scan imaging in acute respiratory distress syndrome.

Computerised tomography (CT) is being used with increasing frequency in acute respiratory distress syndrome (ARDS) patients. This brief review will discuss some of the clinical insights that a CT scan can offer. A large number of CT scan studies have provided new insights into the pathophysiology of ARDS and of mechanical ventilation, and are particularly focused on the recruitment-derecruitment phenomenon. To this end, newer fast CT scan technology promises a dynamic, rather than a static view of lung ventilation.

Adult↗
PubMed2001

Permissive hypercapnia.

The term permissive hypercapnia defines a ventilatory strategy for acute respiratory failure in which the lungs are ventilated with a low inspiratory volume and pressure. The aim of permissive hypercapnia is to minimize lung damage during mechanical ventilation; its limitation is the resulting hypoventilation and carbon dioxide (CO2) retention. In this article we discuss the rationale, physiologic implications, and implementation of permissive hypercapnia. We then review recent clinical studies that tested the effect of various approaches to permissive hypercapnia on the outcome of patients with acute respiratory failure.

Adult↗
PubMed2000

Reverse-thrust ventilation in hypercapnic patients with acute respiratory distress syndrome. Acute physiological effects.

Techniques of tracheal gas insufflation (TGI) have been shown to enhance CO(2) clearance efficiency in mechanically ventilated patients with acute respiratory distress syndrome (ARDS). Clinical studies have explored the effects of such techniques only at moderate intratracheal gas flow rates, with TGI superimposed to mechanical ventilation in a continuous fashion, or synchronized to the expiratory phase of the duty cycle. We examined the effects of intratracheal pulmonary ventilation (ITPV), delivering the entire tidal volume (VT) in the proximity of the tracheal carina, with all the gas flow supplied continuously through a reverse-thrust catheter (RTC). A potential limitation in the application of TGI is dynamic hyperinflation. Therefore, in a subgroup of patients, we also evaluated the effects of ITPV on end-expiratory lung volume (EELV) by respiratory inductive plethysmography (RIP). Eleven patients with ARDS under volume-cycled mechanical ventilation were subsequently switched to ITPV at the same baseline respiratory rate, I:E ratio, and VT. At the same minute volume, Pa(CO(2)) decreased from 70 +/- 12.3 to 59 +/- 9.5 mm Hg, with a percent reduction of 15 +/- 4% (range from 10 to 20%). The CO(2) decrease was greater in patients with higher baseline Pa(CO(2)) levels (DeltaPa(CO(2)) = 0.29 x Pa(CO(2)) - 9.48, r = 0.95). During transition from mechanical ventilation to ITPV, tracheal positive end-expiratory pressure (PEEP(tr)) decreased with a correspondent decrease in EELV. Both were restored by increasing the PEEP at the ventilator by 3.6 +/- 2.0 cm H(2)O. These data suggest that in patients with ARDS ITPV effectively reduces dead space ventilation and the employment of the RTC may limit or avoid dynamic hyperinflation.

Adult↗