Development of the Baylor Gyro Permanently Implantable Centrifugal Blood Pump as a Biventricular Assist Device

The Baylor Gyro permanently implantable centrifugal blood pump (Gyro PI pump) has been under development since 1995 at Baylor College of Medicine. Excellent results were achieved as a left ventricular assist device (LVAD) with survival up to 284 days. Based on these results, we are now focusing on the development of a biventricular assist device (BVAD) system, which requires 2 pumps to be implanted simultaneously in the preperitoneal space. Our hypothesis was that the Gyro PI pump would be an appropriate device for an implantable BVAD system. The Gyro PI 700 pump is fabricated from titanium alloy and has a 25 ml priming volume, pump weight of 204 g, height of 45 mm, and pump diameter of 65 mm. This pump can provide 5 L/min against 100 mm Hg at 2,000 rpm. In this study, 6 half-Dexter healthy calves have been used as the experimental model. The right pump was applied between the infundibular of the right ventricle and the main pulmonary artery. The left pump was applied between the apex of the left ventricle and the thoracic descending aorta. As for anticoagulation, heparin was administered at the first postoperative week and then converted to warfarin sodium from the second week after surgery. Both pump flow rates were controlled maintaining a pulmonary arterial flow of less than 160 ml/kg/min for the sake of avoidance of pulmonary congestion. Blood sampling was done to assess visceral organ function, and the data regarding pump performance were collected. After encountering the endpoint, which the study could not keep for any reasons, necropsy and histopathological examinations were performed. The first 2 cases were terminated within 1 week. Deterioration of the pump flow due to suction phenomenon was recognized in both cases. To avoid the suction phenomenon, a flexible conduit attached on the inlet conduit was designed and implanted. After using the flexible inflow conduit, the required power and the rotational speed were reduced. Furthermore, the suction phenomenon was not observed except for 1 case. There was no deterioration regarding visceral organ function, and pulmonary function was maintained within normal range except for 1 case. Even though the experimental animal survived up to 45 days with the flexible inflow conduit, an increase in power consumption due to thrombus formation behind the impeller became a problem. Lower rotational speed, which was probably produced by the effectiveness of the flexible inflow conduit, was speculated to be one of the reasons. And the minimum range of rotational speed was 1,950 rpm in these 6 BVAD cases and the previous 3 cases of LVAD. In conclusion, 6 cases of BVAD implantation were performed as in vivo animal studies and were observed up to 45 days. The flexible inflow conduit was applied in 4 of 6 cases, and it was effective in avoiding a suction phenomenon. The proper rotational speed of the Gyro PI 700 pump was detected from the viewpoint of antithrombogenicity, which is more than 1,950 rpm.     

负压封闭引流术在脊柱后路内固定术后深部感染治疗中的应用

目的探讨负压封闭引流（vacuum sealing drainage,VSD）在治疗脊柱后路内固定术术后感染中的应用价值。方法回顾性分析2006年1月～2009年12月应用VSD治疗11例脊柱内固定术术后深部感染患者的治疗经过,以总结出合理的诊疗方法。结果11例患者应用VSD技术处理创面1～3次,每次引流7—10d。10例患者保留椎间植骨融合器、椎弓根钉、连接棒,仅取出横连。1例患者术中发现内固定已松动,取出所有内固定。随访6～36个月,所有患者均获得临床治愈。结论VSD技术可以充分引流脊柱后路内固定术术后深部感染伤口的脓液并消灭其死腔;同时增加了取出横连保留其他内固定的安全性,有利于切口早习愈合及尽早进行功能锻炼。     

Emergency management of epidural haematoma through burr hole evacuation and drainage. A preliminary report

Summary Background. Blood clot evacuation through an osteoplastic craniotomy, a procedure requiring neurosurgical expertise and modern medical facilities, is the accepted method for treatment of a pure traumatic epidural haematoma following closed head injury. In certain emergency situations and/or in less sophisticated settings, however, use of this procedure may not be feasible. The present study was undertaken to ascertain whether placement of a burr hole and drainage under negative pressure constituted a rapid, effective and safe approach to manage patients with simple epidural haematomas. Methods. Thirteen patients suffering from a traumatic epidural haematoma were treated from January, 1999 to October, 2002. Twelve patients presented with skull fracture but no fracture was depressed. Placement of flexible tubes through a burr hole, followed by continuous suction under negative pressure, enabled aspiration of the clot and drainage of the cavity. In 8 cases, the procedure was performed under local anaesthesia with 2% Xylocaine™ and with intravenous sedation with propofol as needed. The operative procedure was accomplished within 30 min, and the drainage tube was left in place for 3–5 days. CT scans were performed daily from days 1 to 5. Results. In 11 of 13 cases, clots were evacuated successfully and patients regained consciousness within 2 hours. Recoveries occurred without significant sequelae. In the remaining 2 cases, the drainage tube was found to be obstructed by a blood clot such that the haematoma was unaffected. A traditional craniotomy was performed within 8–12 hours, and these 2 patients recovered consciousness within the subsequent 6 hours. Conclusion. Burr hole evacuation followed by drainage under negative pressure is a safe and effective method for emergency management of a pure traumatic epidural haematoma. To assure safety patients given this procedure should be monitored by daily CT scans. Decompressive craniotomy should be performed if consciousness does not improve within several hours.     

Evaluation of Suction Detection During Different Pumping States in an Implantable Rotary Blood Pump

In recent times, the problem of noninvasive suction detection for implantable rotary blood pumps has attracted substantial research interest. Here, we compare the performance of various suction indices for different types of suction and non‐suction events based on pump speed irregularity. A total of 171 different indices that consist of previously proposed as well as newly introduced suction indices are tested using regularized logistic regression. These indices can be classified as amplitude based (derived from the mean, maximum, and minimum values of a cycle), duration based (derived from the duration of a cycle), gradient based (derived from the first order as well as higher order differences) and frequency based (derived from the power spectral density). The non‐suction event data consists of ventricular ejection with or without arrhythmia and intermittent and continuous non‐opening of the aortic valve. The suction event data consists of partial ventricular collapse that occurs intermittently as well as continuously with or without arrhythmia. In addition, we also attempted to minimize the usage of multiple indices by applying the sequential forward floating selection method to find which combination of indices gives the best performance. In general, the amplitude‐based and gradient‐based indices performed quite well while the duration‐based and frequency‐based indices performed poorly. By having only two indices ([i] the maximum gradient change in positive slope; and [ii] the standard deviation of the maximum value in a cycle), we were able to achieve a sensitivity of 98.9% and a specificity of 99.7%.     

闭式冲洗引流联合VSD治疗早发腰椎内固定术后感染临床探讨

目的探讨应用闭式冲洗引流联合VSD治疗早发腰椎内固定术后感染。方法回顾性分析郑州大学第二附属医院2009年9月—2012年3月5例早发腰椎内固定术后感染患者,根据细菌培养及药敏结果,静脉应用敏感抗生素,保留内置物,早期行清创手术,术中切口内留置冲洗管一根,引流管两根,一期缝合切口,应用敏感抗生素盐水冲洗,切口外置VSD,根据细菌培养结果去除置管及VSD。结果 5例患者冲洗14～21d,平均17d,抗生素应用12周,均获得清创术后一期切口愈合,感染控制,血沉、C反应蛋白、白细胞降至正常水平,腰部症状消失,随访12个月～27个月,无感染复发。结论对于腰椎内固定术后早发感染早期行清创术,术后给予置管闭式冲洗引流,外置VSD是一种简单易行、有效的处理方法,联合应用敏感抗生素可有效控制感染、降低复发率,保留了内置物及植骨块,维持了脊柱稳定性。     

Effectiveness of the endotracheal tube cuff on the trachea: physical and mechanical aspects

Introduction

The inflation pressure of the endotracheal tube cuff can cause ischemia of the tracheal mucosa at high pressures; thus, it can cause important tracheal morbidity and tracheal microaspiration of the oropharyngeal secretion, or it can even cause pneumonia associated with mechanical ventilation if the pressure of the cuff is insufficient.

Objective

In order to investigate the effectiveness of the RUSCH® 7.5 mm endotracheal tube cuff, this study was designed to investigate the physical and mechanical aspects of the cuff in contact with the trachea.

Methods

For this end, we developed an in vitro experimental model to assess the flow of dye (methylene blue) by the inflated cuff on the wall of the artificial material. We also designed an in vivo study with 12 Large White pigs under endotracheal intubation. We instilled the same dye in the oral cavity of the animals, and we analyzed the presence or not of leakage in the trachea after the region of the cuff after their deaths (animal sacrifice). All cuffs were inflated at the pressure of 30 cmH₂O.

Results

We observed the passage of fluids through the cuff in all in vitro and in vivo experimental models.

Conclusion

We conclude that, as well as several other cuff models in the literature, the RUSCH® 7.5 mm tube cuffs are also not able to completely seal the trachea and thus prevent aspiration of oropharyngeal secretions. Other prevention measures should be taken.     

老年腹膜透析患者巴氯芬药物中毒催醒治疗与护理

巴氯芬是一种高效的作用在脊髓部位的肌肉松弛剂,其作用机制和药理学特性均与其他肌肉松弛剂不同。人体中枢神经系统主要抑制性递质氨基丁酸（GABA）的衍生物,通过抑制脊髓的单突触反射和多突触反射的传递,刺激GABAB受体,从而抑制兴奋性神经递质的释放,可作用于脊髓上端而产生中枢神经抑制作用。     

封闭和开放吸痰方法对ICU机械通气患者 疼痛和躁动影响的比较

目的 比较封闭和开放两种吸痰方法对ICU机械通气患者疼痛和躁动的影响。方法 研究对象为2017年5月~12月在首都医科大学大兴教学医院ICU接受机械通气治疗的60例患者。本研究采取单中心、随机对照试验设计的临床研究,采用随机数字表将纳入的患者分到封闭吸痰组和开放吸痰组,每组30例。封闭吸痰为试验组,开放吸痰为对照组。在吸痰操作之前、过程中、结束后即刻、结束后5 min、结束后20 min分别进行行为疼痛评分和Richmond镇静躁动评分。结果 两组的BPS和RASS评分在吸痰操作后均有增高,两种吸痰方法所引起的疼痛和躁动水平增加的幅度基本相同,差异无统计学意义（P＞0.05）。结论 上述两种吸痰方法对ICU机械通气患者疼痛和躁动的影响无显著差异,可能需要更大样本量的研究来证明。     

负压引流预防腹腔镜腹股沟疝修补术后血清肿的应用体会

目的:探讨腹腔镜全腹膜外疝修补术中放置负压引流管对预防术后血清肿的临床价值。方法:选取2013年5月至2016年5月收治的110例腹股沟疝患者,随机分为两组,观察组术中于腹膜前间隙放置负压引流管,对照组不放置负压引流管。观察两组术后血清肿发生率。结果:110例患者中,观察组70例,术后发生1例血清肿,对照组40例,术后发生5例血清肿。结论:腹腔镜全腹膜外疝修补术术中放置负压引流可引流渗液,促进组织修复,预防术后血清肿的发生,容易学习,易于掌握,且一次性负压吸引球囊价格低廉,降低了综合医疗费用,值得临床应用。     

Report of experience in 190 patients with the use of closed suction drainage in arthroscopic knee procedures

The goal of this study is to report our experience with the use of suction drainage for various arthroscopic knee procedures. One hundred and ninety patients who underwent arthroscopic knee procedures participated in the study, and were divided into two groups (Group 1: Suction drainage, Group 2: No suction drainage). For every patient, the following parameters were recorded: age, gender, operative time, tourniquet or pump use, the amount of fluid collected in the hemovac drain, presence of meniscal tear, type of the operative procedure, date of the operation, and presence of effusion at the follow-up. Statistical analysis was performed to detect any significant statistical difference between the amount of fluid collected in the hemovac drain and the other mentioned parameters in Group 1; and these patients were divided into four subgroups to facilitate the statistical evaluation between the procedures and the amount of fluid collected in the hemovac drain. The partial meniscectomy subgroup had significantly lower amounts of collected fluid when compared to the subtotal meniscectomy subgroup. Drilling of the osteochondral faces led to significantly higher amounts of fluid when compared to non-drilling cases. Use of an infusion pump during surgery and shorter operation time led to lower amounts of fluid to be collected. No case in either main group suffered from effusion at the follow-up. Our investigation demonstrated that in different arthroscopic interventions, variable amounts of fluid can be collected in the hemovac drains. Subtotal meniscal resection, drilling of the osteochondral faces and longer duration of the operation increase the amount of fluid. In cases of partial meniscal resection and/or chondral debridement, limited synovial and plica resection, suction drainage is unnecessary.