Characterization and identification of atrial fibrillation drivers in patients with nonparoxysmal atrial fibrillation using simultaneous amplitude frequency electrogram transform.

INSTRUCTION: We hypothesized that real-time simultaneous amplitude frequency electrogram transform (SAFE-T) during sinus rhythm (SR) is able to identify and characterize the drivers of atrial fibrillation (AF) in nonparoxysmal (NP) AF. METHODS: Twenty-one NPAF patients (85.71% males, mean age 52 years old) underwent substrate mapping during SR (SAFE-T and voltage) and during AF (complex fractionated atrial electrograms [CFAE] and similarity index [SI]). After pulmonary veins isolation, extensive substrate ablation was performed with the endpoint of procedural termination or elimination of all SI sites (>63% similarities). Sites with procedural termination and non-termination sites were tagged for postablation SR analysis using SAFE-T. RESULTS: In 74 CFAE sites identified (average of 3 ± 2 sites per person), 28 (37.84%) were identified as termination sites demonstrating a high SI compared with the non-termination sites (80.11 ± 9.57% vs. 45.96 ± 13.38%, p < .001) during AF. During SR, these termination sites have high SAFE-T values and harbor a highly resonant, localized, repetitive high frequency components superimposed in the low frequency components compared with non-termination sites (5.70 ± 3.04 vs. 1.49 ± 1.66 Hz·mV, p < .001). In the multivariate analysis, the termination sites have higher SAFE-T and SI value (p < .001). CONCLUSION: AF procedural termination sites harbored signal characteristics of repetitive, high frequency component of individualized electrogram during SR, which can be masked by the low frequency fractionated electrogram and are difficult to see from the bipolar electrogram. Thus, SAFE-T mapping is feasible in identifying and characterizing sites of AF drivers.

[Acute respiratory distress due to tracheostomy tube migration]. / Détresse respiratoire aiguë par migration d'une canule de trachéotomie.

Tracheostomy cannula care is of paramount importance in the daily management of tracheotomized patients. While some complications are commonplace, specific events can occur, often according to type of cannula. We herein report the case of a 71-year-old patient; following a lengthy stay in the intensive care unit, she had received a Safe T-Tube cannula designed to provide support in a stenotic trachea. At home, while suctioning her tracheal secretions, she suddenly experienced respiratory distress requiring a rapid intervention. On arrival, no seeable cannula was found, either in the tracheostomy or in the patient's immediate surroundings. Following her transfer to intensive care, a new cannula was inserted into the tracheostomy opening, enabling mechanical ventilation to begin and achieving rapid relief of dyspnea and improvement of the patient's overall condition. Bronchial fibroscopy was then performed, during which the Safe T-Tube cannula was found folded on itself in a supra-carinal intra-tracheal position. It was extracted and replaced by a cannula of the same model, which was sewn to the skin. Although rare and usually limited to flexible cannulas, this complication is potentially fatal. Generally speaking, when cannula obstruction is suspected, bronchial endoscopy in an intensive care setting is a vital necessity. It is not only the cornerstone of the diagnosis, but also of paramount importance in treatment taking into full account the mechanism of obstruction.

The surgical repair of benign tracheo-oesophageal/pharyngeal fistula in patients on mechanical ventilation for severe neurological injuries†.

Acquired benign tracheo-oesophageal or pharyngeal fistulas (TO/PF) in neurological patients who cannot be weaned from mechanical ventilation represent a highly demanding clinical problem. We report on 3 patients on intermittent or continuous mechanical ventilation who successfully underwent tracheal resection and direct repair of the digestive fistula. Postoperative mechanical ventilation was provided through a modified silicone Safe-T-Tube, with which the cranial branch can be occluded with an internal inflatable balloon, inserted through tracheostomy performed at or below the level of the cricoid-tracheal suture line. Since the T prosthesis does not have an external cuff in the distal branch, a trans-tracheal open ventilation (TOV) technique was adopted. All patients, after a period that ranged from 21 h to 38 days from surgery, were restored to spontaneous breath; tracheal and oesophageal sutures healed normally.

Is Montgomery tracheal Safe-T-Tube clinical failure induced by biofilm?

OBJECTIVES: Montgomery Safe-T-Tube deterioration and early biofilm colonization may explain the discomfort claimed by many patients and clinical failures. The aim of the study was to analyze the deterioration of Montgomery Safe-T-Tube morphological and mechanical properties in vivo in 16 patients by using microbiological methods, optical and electron microscopy, and engineering tests. STUDY DESIGN: Prospective controlled study at a single medical center. SETTING: University hospital. SUBJECTS AND METHODS: The study, conducted from April 2007 to February 2012 at the "Sapienza" University of Rome, was designed to collect 2 Montgomery Safe-T-Tubes from each patient. The first was removed 3 to 15 days after insertion (group A) and the second at least 90 days after (group B). Specimens underwent microbiologic assays, electron microscopic analysis, immunocytologic analysis, and mechanical tests. RESULTS: Microorganisms were not isolated in 2 group A cases (12%), whereas they were in all group B cases. Biofilm was identified in 11 of 16 (69%) group A samples and in 16 of 16 (100%) group B samples (P = .0149) using scanning electron microscopy. Immunohistochemistry showed monocyte-granulocyte line cells producing interleukin-1ß on the external surfaces of Montgomery Safe-T-Tubes. The tensile test showed that the wear related to the longer period of use makes Montgomery Safe-T-Tubes more rigid than newer ones. CONCLUSION: Early biofilm colonization takes place in Montgomery Safe-T-Tubes in most cases. The mechanical decay could be justified in part by the destructive biofilm activity and by the release of inflammatory effectors and enzymes.

Laryngotracheal stenosis treated with multiple surgeries: experience, results and prognostic factors in 70 patients.

Laryngotracheal stenosis is a complex condition that usually requires multiple procedures to restore physiological respiration. The aim of this study was to evaluate the percentage of decannulation compared to different or multiple surgical treatments. We retrospectively reviewed the charts of 70 patients treated between 1990 and 2005 for laryngotracheal stenosis of various aetiology: iatrogenic stenosis (n = 55), post-traumatic stenosis (n = 11) or other causes (autoimmune disease, n = 3; diphtheria, n = 1). In order to maintain laryngotracheal patency, a Montgomery Safe-T tube was used in all patients as a single dilation treatment or associated with endoscopic and/or open-neck surgery. Fifty-four of the 70 patients (77.1%) were eventually decannulated; 39 of these (72.2%) underwent 3 or fewer surgical procedures, showing a significant difference compared to patients who underwent more than 3 surgeries (p = 0.00002). A total of 257 surgeries were performed. Only seven of 54 patients (13%) were decannulated after more than 5 surgical procedures. Patients over 60 years of age and with a higher grade of stenosis showed a significantly lower success rate (p = 0.0017 and p = 0.007, respectively). There was no significant correlation between the rate of decannulation and gender, aetiology, site of stenosis or surgery. Patients undergoing dilation for laryngotracheal stenosis usually require multiple procedures. The T tube plays an important role in the treatment of this pathology. However, if the tracheostomy is not removed within 3 surgical interventions, the odds of decannulating the patient decrease significantly, and additional surgeries may be of questionable therapeutic benefit.