Safety and Feasibility of Noninvasive Electromagnetic Stimulation of the Phrenic Nerves.

BACKGROUND: Mechanical ventilation is widely used in ICU patients as a lifesaving intervention. Diaphragmatic atrophy and thinning occur from lack of contractions of the diaphragm during mechanical ventilation. It may prolong weaning and increase the risk of respiratory complications. Noninvasive electromagnetic stimulation of the phrenic nerves may ameliorate the atrophy seen with ventilation. The objective of this study was to show that noninvasive repetitive electromagnetic stimulation is safe, feasible, and effective to stimulate the phrenic nerves in both awake individuals and anesthetized patients. METHODS: A single-center study with 10 subjects overall, 5 awake volunteers and 5 anesthetized subjects. We used a prototype electromagnetic, noninvasive, simultaneous bilateral phrenic nerve stimulation device in both groups. In the awake volunteers, we assessed time-to-first capture of the phrenic nerves and safety measures, such as pain, discomfort, dental paresthesia, and skin irritation. In the anesthetized subjects, time-to-first capture as well as tidal volumes and airway pressures at 20%, 30%, and 40% stimulation intensity were assessed. RESULTS: Diaphragmatic capture was achieved in all the subjects within a median (range) of 1 min (1 min to 9 min 21 s) for the awake subjects and 30 s (20 s to 1 min 15 s) for the anesthetized subjects. There were no adverse or severe adverse events in either group, nor any dental paresthesia, skin irritation, or subjective pain in the stimulated area. Tidal volumes increased in all the subjects in response to simultaneous bilateral phrenic nerve stimulation and increased gradually with increasing stimulation intensity. Airway pressures corresponded to spontaneous breathing of ∼2 cm H2O. CONCLUSIONS: Noninvasive phrenic nerve stimulation can be safely performed in awake and anesthetized individuals. It was feasible and effective in stimulating the diaphragm by induction of physiologic and scalable tidal volumes with minimum positive airway pressures.

The Veres adapter: clinical experience with a new device for jet ventilation via a laryngeal mask airway during flexible bronchoscopy.

BACKGROUND: A new device was developed to deliver high-frequency jet ventilation via a laryngeal mask airway (LMA). We investigated its use during flexible fiberoptic bronchoscopy in anesthetized patients. METHODS: Thirty adults were studied during interventional bronchoscopy. After facemask ventilation, the Veres adapter was connected to a size 4 or 5 LMA, and superimposed high-frequency jet ventilation was performed. Oxygen saturation, transcutaneous carbon dioxide, supraglottic airway pressure, and hemodynamic data were recorded and analyzed. RESULTS: Procedures were performed under stable hemodynamic conditions. Short procedure times and fast recovery were observed. Mild hypercapnia was the most common minor adverse effect (n = 16). One patient developed a pneumothorax after peripheral biopsy, 1 patient had a stiff chest during bronchoscopy, resulting in high airway pressures, and 1 patient required continuous positive airway pressure mask ventilation in the postoperative care unit. CONCLUSIONS: We report the clinical use of the Veres adapter in conjunction with an LMA to achieve rapid surgical access and adequate ventilation during flexible bronchoscopy. As an alternative to the use of an endotracheal tube, the new system may better maintain the airway during interventional and diagnostic bronchoscopy because of the larger diameter conduit.

[Management of malignant and benign airway stenosis by stent implantation]. / Malignus és benignus légúti szukületek megoldása légúti protézis (stent) beültetésével.

INTRODUCTION: In the last few decades the different bronchoscopic procedures have gained an important role in the treatment of airway stenosis, and the number of implanted airway stents has also greatly increased. PATIENTS: Between 1998 and 2004 the authors implanted altogether 108 airway prosthesis in 90 patients at the Institute of Pulmonology of Pest County. 58% of the patients were males, 42% females, the average age was 57.5 years, the average follow-up time was 7 months. RESULTS: On the basis of different etiology the patients were separated into two main groups. In 57% the airway stenosis was caused by malignant illnesses, in these cases stents can be used only with palliative purpose. However, in case of benign lesions they can offer a long-term solution and require an adequate follow-up of the patients. The authors' main aim was to get an overall picture of the interventions they had done by processing the data, with the help of the measurable characteristics that make possible to follow the airways' permeability and its changes. Analysing the results of the respiratory function and blood gas examinations they didn't find a significant difference inspite of the subjective improvement.