Bronchial blockers under pressure: in vitro model and ex vivo model.

BACKGROUND: Pressures (Pe) exerted by bronchial blockers on the inner wall of the bronchi may cause mucosal ischaemia. Our aims were as follows: (i) to compare the intracuff pressure (Pi) and Pe exerted by commercially available bronchial blockers in an in vitro and an ex vivo model; (ii) to investigate the influence of both the inflated intracuff volume and cuff diameter on Pe; and (iii) to estimate the minimal sealing volume (VSmin) and the corresponding Pe for each bronchial blocker studied. METHODS: The Pe exerted by seven commercial bronchial blockers was measured at different inflation volumes using a custom-designed system using in vitro and ex vivo animal models with two internal diameters (12 and 15 mm). RESULTS: In the same conditions, Pi was significantly lower than Pe (P<0.05), and Pe was higher in the in vitro model than in the ex vivo model. The Pe increased with the inflated volume, with use of the small-diameter model (P<0.05). Ex vivo models needed a higher minimal sealing volume than the in vitro models, and this volume increased with the diameter (e.g. the VSmin at a positive pressure of 25 cm H2O required a Pe ranging from 12 to 78 mm Hg on the 15 mm ex vivo model and from 66 to 110 mm Hg on the 12 mm ex vivo model). CONCLUSIONS: The Pi cannot be used to approximate Pe. The diameter of the model, the inflated volume, and the bronchial blocker design all influence Pe. A pressure higher than the critical ischaemic threshold (i.e. 25 mm Hg) was needed to prevent air leak around the cuff in the in vitro and ex vivo models.

Design and characterization of a measurement system for monitoring pressure exerted by bronchial blockers: In vitro trials.

Bronchial blockers (BBs) allow occluding the bronchial duct and collapsing the "dependent" lung in a number of thoracic surgery. The occlusion is obtained through a cuff that, inflated with a proper air volume, exerts a pressure, Pe, on the inner wall of the mainstem bronchus. In this work a measurement chain, based on two piezorestistive force sensors, was developed and calibrated to measure Pe exerted by six BBs, as a function of inflated volume on in vitro models (two latex ducts with diameters similar to the ones of the adult mainstem bronchi: 12 mm and 15 mm). Pe showed wide changes considering different BBs, and significantly increases with the decrease of the model's diameter, at the same inflated volume. Lastly, the minimum occlusive volume (MOV) to sail the two models was estimated for each BB. These experiments were performed by applying a pressure difference across the cuff of 25 cmH2O, in order to simulate the worst condition in a clinical scenario. Results show that MOV depends on both the type of BB and the duct diameter. The knowledge of this volume allows estimating the minimum value of Pe exerted by BBs to avoid air leakage.

Cytoreductive surgery (cs) and hyperthermic intraperitoneal chemotherapy (hipec) in treatment of peritoneal surface malignances: report of a phase II clinical study.

Peritoneal surface malignancy is the expression of a spectrum of disease involving the peritoneum primary or secondary to gastrointestinal and gynecological neoplasms. Even if intraperitoneal therapy has now been demonstrated in multiple randomized trials to improve the outcome of chemotherapy for patients with optimally debulked or small volume ovarian carcinoma, it is believed that peritoneal carcinomatosis is considered an advanced stage of disease; for this reason, it is treated with systemic chemotherapy and surgery plays only a palliative role (1). In the last twenty years, some centres have developed surgical treatment of peritoneal carcinomatosis that involves aggressive cytoreductive surgery associated with hyperthermic intraperitoneal chemotherapy. This treatment has improved and prolonged survival, despite the associated high morbidities and mortalities (3-14).

[Diagnostic and therapeutic value of hysteroscopy in intrauterine synechiae]. / Validità diagnostica e terapeutica dell'isteroscopia nella patologia aderenziale intrauterina.

The paper evaluates the diagnostic and therapeutic value of hysteroscopy in a group of women suffering from intrauterine synechiae secondary to intrauterine mechanical manipulation following spontaneous abortion.

[Cervical endometriosis: usefulness of colposcopic examination in the diagnosis]. / L'endometriosi cervicale: utilità dell'esame colposcopico nell'approccio diagnostico.

Six cases of cervical endometriosis out of 420 colposcopies (1.42%) are described. The data suggest a correlation between electrocautery or other cervical trauma and cervical endometriosis. This study confirms that colposcopic examination is indispensable for a correct diagnosis of cervical endometriosis.

Signal-averaged electrocardiograms in patients with atrial fibrillation or flutter.

The signal-averaged QRS complex that is prolonged because of low amplitude late potentials predicts ventricular tachycardia. This study investigated if signal-averaged low amplitude atrial potentials predict atrial fibrillation or flutter (AFF). Low amplitude potentials were considered to be high-frequency, high amplitude P (HiFP) duration recorded between 50 and 250 Hz at 1.0 mm/microV amplitude minus unfiltered P (UnFP) duration at 0.1 mm/microV. In nine normals, HiFP averaged 115.6 msec +/- 9.8 SD. HiFP were wider in 26 control patients (133.5 msec +/- 15.7, p less than 0.005) but HiFP-UnFP (11.2 msec +/- 8.5) and signals less than 10 microV terminating HiFP inscription (21.7 msec +/- 23.4) were similar to normal values. Seventeen patients with paroxysmal or recently cardioverted AFF did not have significantly longer intervals than controls (HiFP averaged 138.8 msec +/- 23.0, HiFP-UnFP 13.2 msec +/- 9.3, and signals less than 10 microV 32.4 msec +/- 19.5). Therefore, signal-averaged P waves do not identify patients with AFF.

Repolarization abnormalities in mitral valve prolapse.

Inferolateral ST depression, T wave inversion, and QT prolongation have been frequently described in reports of largely symptomatic mitral valve prolapse (MVP) patients, but not in a recent population-based survey of mainly asymptomatic subjects with MVP. To learn if there is a relationship between these ECG changes and symptoms, physical findings or hemodynamic sequelae, we reviewed ECGs from 119 patients, ages 18 to 60 years who had MVP diagnosed by echocardiography. Seventy-four percent had symptoms characteristic of MVP. ST-T changes were found as frequently in asymptomatic patients (29%) as in those symptomatic (27%), and did not identify those with hemodynamic sequelae of MVP (apical systolic murmurs, Doppler-defined mitral regurgitation, or left atrial enlargement). QT prolongation was found more frequently in the symptomatic group (25% vs 10%) but did not predict syncope. When compared to the expected 0.9% prevalence of ST abnormalities in a normal population, ST-T changes and QT prolongation are indeed frequent in MVP, but are not useful in identifying clinically important subsets.