Diaphragm Activation in Ventilated Patients Using a Novel Transvenous Phrenic Nerve Pacing Catheter.

OBJECTIVES: Over 30% of critically ill patients on positive-pressure mechanical ventilation have difficulty weaning from the ventilator, many of whom acquire ventilator-induced diaphragm dysfunction. Temporary transvenous phrenic nerve pacing using a novel electrode-bearing catheter may provide a means to prevent diaphragm atrophy, to strengthen an atrophied diaphragm, and mitigate the harms of mechanical ventilation. We tested the initial safety, feasibility, and impact on ventilation of this novel approach. DESIGN: First-in-Humans case series. SETTING: Angiogram suite. PATIENTS: Twenty-four sedated, mechanically ventilated patients immediately prior to an elective atrial septal defect repair procedure. INTERVENTIONS: A 9.5-Fr central venous catheter with 19 embedded electrodes was placed via Seldinger technique into the left subclavian vein and superior vena cava and evaluated for up to 90 minutes. The electrode combinations determined to provide best transvenous stimulation of the right and left phrenic nerves were activated in synchrony with mechanically ventilated breaths. MEASUREMENTS AND MAIN RESULTS: One patient could not be tested for reasons unrelated to the device. In the 23 patients who underwent the full protocol, transvenous stimulation activated the diaphragm in 22 of 23 (96%) left phrenic capture attempts and 20 of 23 (87%) right phrenic capture attempts. In one subject, a congenital left-sided superior vena cava precluded right-sided capture. Significant reductions in ventilator pressure-time-product were achieved during stimulation assisted breaths in all 22 paced subjects (range, 9.9-48.6%; p < 0.001). There were no adverse events either immediately or at 2-week follow-up. CONCLUSIONS: In this First-in-Human series, diaphragm pacing with a temporary catheter was safe and effectively contributed to ventilation in conjunction with a mechanical ventilator.

Mitigation of Ventilator-induced Diaphragm Atrophy by Transvenous Phrenic Nerve Stimulation.

RATIONALE: Ventilator-induced diaphragm dysfunction is a significant contributor to weaning difficulty in ventilated critically ill patients. It has been hypothesized that electrically pacing the diaphragm during mechanical ventilation could reduce diaphragm dysfunction. OBJECTIVES: We tested a novel, central line catheter-based, transvenous phrenic nerve pacing therapy for protecting the diaphragm in sedated and ventilated pigs. METHODS: Eighteen Yorkshire pigs were studied. Six pigs were sedated and mechanically ventilated for 2.5 days with pacing on alternate breaths at intensities that reduced the ventilator pressure-time product by 20-30%. Six matched subjects were similarly sedated and ventilated but were not paced. Six pigs served as never-ventilated, never-paced control animals. MEASUREMENTS AND MAIN RESULTS: Cumulative duration of pacing therapy ranged from 19.7 to 35.7 hours. Diaphragm thickness assessed by ultrasound and normalized to initial value showed a significant decline in ventilated-not paced but not in ventilated-paced subjects (0.84 [interquartile range (IQR), 0.78-0.89] vs. 1.10 [IQR, 1.02-1.24]; P = 0.001). Compared with control animals (24.6 µm2/kg; IQR, 21.6-26.0), median myofiber cross-sectional areas normalized to weight and sarcomere length were significantly smaller in the ventilated-not paced (17.9 µm2/kg; IQR, 15.3-23.7; P = 0.005) but not in the ventilated-paced group (24.9 µm2/kg; IQR, 16.6-27.3; P = 0.351). After 60 hours of mechanical ventilation all six ventilated-paced subjects tolerated 8 minutes of intense phrenic stimulation, whereas three of six ventilated-not paced subjects did not (P = 0.055). There was a nonsignificant decrease in diaphragm tetanic force production over the experiment in the ventilated-paced and ventilated-not paced groups. CONCLUSIONS: These results suggest that early transvenous phrenic nerve pacing may mitigate ventilator-induced diaphragm dysfunction.

Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Obturated with Resin Based Adhesive Sealers with Conventional Obturation Technique: An In vitro Study.

BACKGROUND: To compare fracture resistance of endodontically treated teeth obturated with different resin-based adhesive sealers with a conventional obturation technique. MATERIALS AND METHODS: A total of 60 Single canaled teeth were divided into five groups. The first group was taken as a negative control. The rest of the groups were shaped using ProFile rotary files (Dentsply Maillefer, Ballaigues, Switzerland). The second group was obturated with gutta-percha and a ZOE-based sealer Endoflas FS (Sanlor Dental Products, USA). The third group was obturated with gutta-percha and an epoxy-based sealer AH Plus (Dentsply, DeTrey, Germany). The fourth group was obturated with Resilon (Pentron Clinical Technologies, Wallingford, CT) and RealSeal sealer (Pentron Clinical Technologies). The fifth group was obturated with EndoREZ points and EndoREZ sealer (both from Ultradent, South Jordan, UT). Roots were then embedded into acrylic blocks and were then fixed into a material testing system and loaded with a stainless steel pin with a crosshead speed of 5 mm/min until fracture. The load at which the specimen fractured was recorded in Newtons. RESULTS: It was found that forces at fracture were statistically significant for the newer resin systems, Resilon, and EndoREZ. CONCLUSION: It was concluded that roots obturated with newer resin systems (Resilon and EndoREZ) enhanced the root strength almost up to the level of the intact roots.

Trichorrhexis nodosa with nail dystrophy: diagnosis by dermoscopy.

A 25-year-old male, born of non-consanguineous marriage presented with complaints of sparse and thin hairs over scalp and dystrophy of nails since childhood. This case highlights the association of trichorrhexis nodosa with nail dystrophy and the use of trichoscopy as a noninvasive method for diagnosis of hair disorders.