Motility Disorders after Roux-en-Y Gastrojejunostomy

About 30% of patients who have a Roux-en-Y gastrojejunostomy after gastrectomy suffer from abdominal pain, nausea, vomiting of food and bloating made worse by eating. This syndrome, called the Roux stasis syndrome, is caused, in part, by a motility disorder of the Roux limb. Transection of the jejunum during the construction of the limb separates the limb from the natural small intestinal pacemaker located in the duodenum. Ectopic pacemakers then appear in the limb and trigger retrograde contractions in its proximal portion. These contractions slow transit through the limb and result in Roux stasis. Current nonsurgical treatment of the syndrome includes the use of prokinetic agents and intestinal pacing, neither of which has demonstrated long-term benefits. A near-total gastrectomy may speed upper gastrointestinal transit somewhat, but stasis in the Roux limb often persists. Our current approach aims at preventing the syndrome by the use of an ‘uncut’ Roux limb, an operation which preserves myoneural continuity between the duodenal pacemaker and the Roux limb and so prevents the appearance of ectopic pacemakers and stasis in the limb.     

胺碘酮抑制缺血浦肯野纤维起搏离子流

目的观察正常及模拟“缺血”时胺碘酮对绵羊心室浦肯野纤维起搏离子流（Ｉｆ）的影响。方法双微电极电压钳制术,使膜电位过度极化以激活Ｉｆ。结果胺碘酮１×１０－５ｍｏｌ／Ｌ在正常台氏液中显著降低浦肯野纤维Ｉｆ幅值;模拟“缺血”也使Ｉｆ幅值降低,在此基础上,胺碘酮使Ｉｆ幅值进一步减小,加剧了“缺血”对Ｉｆ离子流的抑制作用。结论提示胺碘酮能抑制心肌缺血时心室正常自律性活动。     

Syncope after effort

A 29-year-old man developed recurrent syncope following exertion. Cardiac investigations revealed no evidence of structural heart disease, but during exercise testing, in the recovery phase, he sustained a bradycardia and then asystole for a prolonged period. Before cardiac massage could be instituted a tonic-clonic fit occurred, and this initiated a return to sinus rhythm. His symptoms were abolished following the implantation of a dual-chamber pacemaker.     

Prospective analysis of a surgical algorithm to achieve ventilator weaning in cervical tetraplegia

Objectives: Chronic ventilator dependency in cervical tetraplegia is associated with substantial morbidity. When non-invasive weaning methods have failed the primary surgical treatment is diaphragm pacing. Phrenic nerve integrity and diaphragm motor units are requirements for effective pacing but may need to be restored for successful weaning. A surgical algorithm that includes: 1. Diaphragm pacing, 2. Phrenic nerve reconstruction, and 3. Diaphragm muscle replacement, may provide the capability of reducing or reversing ventilator dependency in virtually all cervical tetraplegics.Design: Prospective case series.Setting: A university-based hospital from 2015 to 2019.Participants: Ten patients with ventilator-dependent cervical tetraplegia.Interventions: I. Pacemaker alone, II. Pacemaker + phrenic nerve reconstruction, or III. Pacemaker + diaphragm muscle replacement.Outcome measures: Time from surgery to observed reduction in ventilator requirements (↓VR), ventilatory needs as of most recent follow-up [no change (NC), partial weaning (PW, 1–12 h/day), or complete weaning (CW, >12 h/day)], and complications.Results: Both patients in Group I achieved CW at 6-month follow-up. Two patients in Group II achieved CW, and in another two patients PW was achieved, at 1.5–2-year follow-up. The remaining two patients are NC at 6 and 8-month follow-up, respectively. In group III, both patients achieved PW at 2-year follow-up. Complications included mucous plugging (n = 1) and pacemaker malfunction requiring revision (n = 3).Conclusion: Although more investigation is necessary, phrenic nerve reconstruction or diaphragm muscle replacement performed (when indicated) with pacemaker implantation may allow virtually all ventilator-dependent cervical tetraplegics to partially or completely wean.     

Pacing in adults with congenital heart disease

Adults with congenital heart disease constitute one of the fastest growing populations in cardiology. Pacing is an integral part of their therapy and may reduce their morbidity and mortality significantly. The current generation of pacemakers is more sophisticated and complex, and they are being utilized for indications other than conduction abnormalities, such as termination of tachycardia and improvement of heart failure. The complex anatomy and history of multiple previous surgeries in adults with congenital heart disease, however, pose many limitations and technical challenges related to the placement of a pacemaker. Unique and innovative approaches to endocardial lead placement and improved epicardial leads is making pacemaker implantation more feasible in these patients.     

Entrainment of the Circadian Rhythm in Rat Pineal N-Acetyltransferase Activity Under Extremely Long and Short Photoperiods

Entrainment of a pacemaker driving the circadian rhythm in rat pineal N-acetyltransferase activity was studied under extremely long and short photoperiods. Adult male rats maintained under the light-dark regime (LD) 18:6 or under the regime LD 6:18 were exposed to a 1-min light pulse at different times at night, then they were released into darkness, and the next night phase-shifts of the evening N-acetyltransferase rise and of the morning N-acetyltransferase decline caused by light pulses were determined. The evening rise was phase-delayed by at most 0.5 h under LD 18:6, but by as much as 2.8 h under LD 6:18. The morning decline was phase-advanced by at most 1.9 h under LD 18:6, but by as much as 3.5 h under LD 6:18. Hence, the magnitude of phase-shifts and consequently patterns of phase-response curves, which show possibilities of discrete entrainment, depend on the photoperiods under which animals are maintained. A 1-min light pulse applied within 1 h before the end of the dark period phase-advanced the morning N-acetyltransferase decline under LD 18:6 as well as under LD 6:18, while a pulse applied within 1 h after the beginning of the dark period phase-delayed the evening N-acetyltransferase rise only in rats maintained under LD 18:6, but not in those kept under LD 6:18. It seems that under very long photoperiods, the N-acetyltransferase rhythm may be entrained by evening as well as by the morning light, while under very short photoperiods the rhythm may be synchronized by morning light only.     

绷带卷加压包扎预防起搏器植入术后囊袋出血的应用效果

目的 探讨绷带卷加压包扎在永久心脏起搏器植入术后囊袋止血中的应用效果.方法 选取永久心脏起搏器植入患者591例,分为试验组和对照组.试验组(296例)用两个医用绷带卷并排放置于起搏器囊袋上方,与切口平行,3M胶布条固定绷带卷,松紧以伤口不出血、绷带卷无移位为准,术后6 h松解胶布条和绷带卷.对照组(295例)将1 000 g沙袋置于起搏器囊袋上方,术后6 h取走沙袋.比较两组患者压迫止血的安全性和有效性.结果 两组在切口出血、囊袋血肿和皮肤压力性损伤发生方面比较差异无统计学意义(P>0.05);试验组切口疼痛、尿潴留和睡眠障碍的发生率低于对照组,比较差异有统计学意义(P<0.05).结论 绷带卷加压包扎法可明显减少患者伤口疼痛、尿潴留、睡眠障碍的发生.