How respiratory system mechanics may help in minimising ventilator-induced lung injury in ARDS patients.

The main supportive therapy in acute respiratory distress syndrome patients is mechanical ventilation. As with any therapy, mechanical ventilation has side-effects, and may induce lung injury (ventilator-induced lung injury (VILI)/ventilator-associated lung injury). The mechanical factors responsible for VILI are thought to be related to tidal recruitment/derecruitment of previously collapsed alveoli and/or pulmonary overdistension. The volume/pressure (V/P) curve of the respiratory system in patients as well as in animal models of acute lung injury (ALI) has a characteristic sigmoid shape, with a lower inflection point (LIP) corresponding to the pressure/end-expiratory volume required to initiate recruitment of collapsed alveoli, and an upper inflection point (UIP) corresponding to the pressure/end inspiratory volume at which alveolar overdistension occurs. "Protective" ventilatory approaches have therefore set out to minimise mechanical injury by using the V/P curve to individualise positive end-expiratory pressure (PEEP) (PEEP above the LIP) and tidal volume (by setting end-inspiratory V/P below the UIP) since a large number of experimental studies correlate P/V curves to histological and biological manifestations of VILI and two randomised trials showed that protective ventilatory strategy individually tailored to the P/V curve minimised pulmonary and systemic inflammation and decreased mortality in patients with ALI. However, despite the fact that several studies have: 1) proposed new techniques to perform pressure/volume curves at the bedside, 2) confirmed that the lower inflection point and upper inflection point correspond to computed tomography scan evidence of atelectasis and overdistension, and 3) demonstrated the ability of the pressure/volume curve to estimate alveolar recruitment with positive end-expiratory pressure, no large studies have assessed whether such measurement can be performed in all intensive care units as a monitoring tool to orient ventilator therapy. Preliminary experimental and clinical studies show that the shape of the dynamic inspiratory pressure/time profile during constant flow inflation (stress index), allows prediction of a ventilatory strategy that minimises the occurrence of ventilator-induced lung injury.

[Complications of tracheostomy in critically ill patients: comparison of dilation and surgical techniques]. / Confronto sulle complicanze di varie tecniche tracheotomiche in area critica.

The tracheotomy, one of the oldest surgical procedures, has in recent years been the focus of particular attention given the undoubted, and not always justified, increase in indications, and by the introduction of dilatational tracheotomy techniques, particularly in critically patients. The present work compares the standard surgical tracheotomy with the more recent percutaneous techniques (Ciaglia dilatational tracheotomy and Fantoni translaryngeal tracheotomy). In particular, the relationship between the technique adopted, timing and complications were analyzed for 215 tracheotomies performed at different Intensive Care Units at our Hospital between 1993 and 1998 (106 performed using the standard surgical technique, 51 with the Ciaglia technique and 58 with the Fantoni technique). The pre-operative oro-tracheal intubation time ranged between 4-54 days (17 tracheotomies performed before oro-tracheal intubation). The results of this study showed that percutaneous techniques present fewer early post-operative complications (severe bleeding, erosive stomitis, dislocation of the cannula) and above all fewer sequelae in time (tracheal stenosis, tracheomalacia). The surgical procedures are shorter and nursing is limited to a few days which certainly results in a savings in health care resources. After decannulation, the esthetic result in patients that underwent the dilatational tracheotomy can be considered excellent. Among the disadvantages one must recall the possible dislocation of the cannula immediately after surgery: forced reinsertion of the cannula exposes the patient to the risk of creating a dangerous false route. The results obtained are statistically significant and in line with those found in the literature. The conclusion is drawn that, when performed by skilled surgeons and aided by endoscopy, the percutaneous tracheotomy techniques are the method of choice for patients in critical areas.

[Hyponatremia in neurosurgical patients]. / Iposodiemia nel paziente neurochirurgico.

Hyponatremia played an essential role in this case, determining the rapid transition from consciousness to a state of coma in female patient who had just come through the critical phase of intensive care. This circumstance underlines the importance of a correct water balance in patients undergoing neurosurgery, as well as a knowledge of the inappropriate antidiuretic hormone secretion (SIADH) syndrome responsible, either alone or in association, for the genesis of severe hyponatremia. In the differential diagnosis of hyponatremia, it is important to recall the role of an often mistaken syndrome (cerebral salt wasting syndrome) characterized by the secretion of a natriuretic factor that has still not been clearly identified.

[A double-blind study of neostigmine versus placebo in paralytic ileus as a result of surgical interventions]. / Studio in doppia cecità tra neostigmina en versus placebo nell'ileo paralitico conseguente ad interventi chirurgici.

A fully randomized double-blind study, stratified according to diagnosis, was carried out in order to assess the effect of endonasal neostigmine in the treatment of post-laparotic paralytic ileus. A total of 40 patients (16 M, 24 F), aged between 22 and 76 years old, were admitted to the study; of these 20 were cholecystectomized and 20 had undergone emergency surgery. According to a special randomization list, 10 patients from each pathological group were treated with 6% neostigmine en (1 puff = 5.4 mg) and the other ten were treated with placebo. Both treatments were administered at a dose of 2 puffs, one per nostril, at the end of surgery and then repeated every 4 hours up to a maximum of 6 puffs/day. Treatment was continued for 4 days or until canalization of feces and gas was achieved. The mean daily dose of endonasal neostigmine found to be efficacious was 4 puffs/day, equivalent to 24.7 mg in cholecystectomized patients and 23.5 mg in patients undergoing emergency surgery. In over-all terms the canalization of gas and feces was observed in 74% of patients treated with neostigmine and in 45% of those receiving placebo and the difference was statistically significant.