TECHNICAL CONSIDERATIONS IN CANNULATING THE ASCENDING AORTA

A successfully used technique of aortic arch cannulation is reported. This cannula is inexpensive and can be made easily in the hospital. The position and advantages of the cannula are discussed.     

The use of cerebral ventriculography for verification of intracerebroventricular cannula placement in the live rat

A technique using cerebral ventriculography for verification of intracerebroventricular cannula placement in the live rat is described. A radiopaque contrast medium, diatrizoate meglumine, was injected into the right lateral ventricle through a cannula stereotaxically implanted into the brain. Radiographic visualization of the radiopaque contrast material in the lateral ventricle and the subarachnoid space verified cannula placement. Transient muscular spasms were observed in about 38% of the injected rats but no lasting changes were observed in the behavior or appearance of these rats.     

Perfusion fixation of the newborn opossum: equipment and techniques.

A 30-gauge cannula was used to perfuse fixative through the fragile heart of a newborn opossum. The cannula was gently maneuvered into the heart and held in place with a specially designed manipulator. The flow rate of the fixative was regulated with an infusion set connected to the cannula.     

A technique for chronic intragastric drug administration in the rat

An improved method for chronic intragastric delivery of drug solutions in the rat is described. The cannula can be easily constructed while the implantation is a simple and a problem-free procedure. Animals suffered no ill effects and resumed normal weight gain profiles after the operation. Since this is a direct stomach cannulation technique, the problems associated with the nasopharyngeal method are avoided. The cannula was tested by administering methadone and observing the characteristic depression of operant responding for food reinforcement. Using the cumulative records, it was possible to detect the onset of drug effect which was found to be about 10 minutes. The cannula is relatively durable and has remained patent in some animals for as long as 10 months without maintenance.     

The metabolism of dopamine in rat caudate nucleus can be increased by in vivo “dialysis” perfusion cannulae

The development of dialysis cannula techniques coupled with high performance liquid chromatography and electrochemical detection (HPLC-EC) has provided a means to continuously sample extracellular fluid from deep brain structures $\text{in vivo}$. The present studies show that with HPLC-EC analysis of the acid metabolites of dopamine (DA) and 5-hydroxytryptamine (5-HT) in samples from dialysis cannulae implanted in the caudate nucleus of anaesthetized rats, it is possible to determine the time course of the response of dopamine- and 5-HT containing neurones to administration of monoamine oxidase inhibitors and haloperidol. The tissue concentrations of the DA and 5-HT metabolites were also determined at the conclusion of each individual experiment in both the caudate nucleus containing a cannula and in that without a cannula. In perfusion experiments where no drug was administered the content of the DA metabolites, but not that of the 5-HT metabolite, were significantly elevated in the caudate nucleus containing the cannula as compared with the contralateral tissue. These increases occurred whether the cannula was perfused or not, suggesting that the presence of the cannula may have been causing a lesion which altered the activity of the DA neurones. These results emphasize the importance of tissue analysis in conjunction with the dialysis experiments, especially where perfusion sample contents of the monoamine metabolites are being measured as a reflection of the effects of behavioural manipulation or drug treatment on endogenous neuronal activity.     

Quinton-Scribner Cannulas for Hemodialysis—Review of Four Years' Experience

Data on a study group of 52 maintenance hemodialysis patients cannulated with Quinton-Scribner cannula in a four-year period were analyzed. The average period of dialysis was 11.8 months with either a pumped coil or a pumpless Kiil artificial kidney system. One hundred and forty-five cannulations were performed. The mean arterial cannula survival was 7.8 months and the mean venous cannula survival was 7.2 months. The exceptional longevity of cannula survival occurred despite the high incidence of atherosclerotic changes at operation and the advanced mean age (47 years) of the patients. The cannula longevity may be partially related to the technique used and to meticulous surgical care given the patient before and after cannulation.Complications from cannulation included two deaths, one from septic pulmonary embolism of Staphylococcus origin, and one from acute Pseudomonas endocarditis. A total of 36 infections of cannulas were recognized, the majority being due to Staphylococcus aureus, but 28 percent being secondary to Gram-negative bacteria.     

Comparison of two techniques for obtaining endometrial bacteriologic cultures in the mare

The endometria of 39 mares were cultured simultaneously using a swab guarded with a double cannula and distal, teflon plug and an unguarded swab with a single, open cannula. Sheep blood (5%) agar, Mac-Conkey's agar, and Sabourad's agar media were innoculated with each swab. The presence of bacterial or fungal growth was determined after 24 and 48 hours of aerobic incubation at 37 C. There were significantly more plates that failed to yield bacterial or fungal growth when streaked with swab specimens obtained with the guarded cannula than when streaked with those obtained with the unguarded cannula. It was concluded that while culturing the endometrium of mares for bacteria or fungi, the use of a guarded instrument consisting of a double cannula with a closed end will result in the recovery of fewer contaminants; therefore, it will be more likely to result in a more accurate representation of uterine bacterial and fungal flora.     

Peritoneal dialysis in infants.

A commercially available closed dialysis system and a new peritoneal cannula with potential advantages for infants have been developed. The dialysis set includes three dialysate bags that may be connected to the filling burette; the warming coil of the set is placed in a thermostatically controlled water bath. The peritoneal catheter comprises a flexible tube with side holes and a sharp short bevelled needle with obturator. Advantages of the new equipment over previously available equipment are that the cannula is easier to insert; there is less risk of contaminating the dialysate since the tubing set is unbroken from supply to cannula; the mix of the dialysate may be changed easily without interrupting dialysis; and the equipment may be assembled easily by unskilled staff.     

Improved method for bile collection in unrestrained conscious rats.

We describe an improved method for continuous collection of bile from unrestrained rats. Use of an externally accessible, continuous-loop cannula when cannulating the common bile duct allows for full recovery from anesthetic effects and maintenance of a normal bile salt pool until the cannula loop is cut. Bile resulting from the cut cannula is diverted into a surgically implanted glass collection vessel and removed periodically via an externalized sampling port. Bile flow over a 24-hour collection period averaged 0.98 +/- 0.04 ml/hr (Mean +/- SEM, n = 9) with no gross pathological changes noted upon necropsy. This technique offers the capability of reestablishing conditions as close to physiologic as possible postsurgery to minimize potential artifacts during bile collection.     

A simple non-surgical method of intrabronchial instillation for the establishment of respiratory infections in the rat.

A technique involving intubation of weanling rats for intrabronchial instillation of infectious material has been developed to produce a respiratory infection model suitable for experimental infection studies. The technique is performed simply with the use of a metal cannula and an intravenous plastic cannula, and dispenses with the need for illumination, laryngoscopy and extensive manipulation of the animal.     

Ultrasound-guided cannulation of the caudal vena cava in the bovine for selective sampling of ovarian effluent

The accuracy of real-time, B-mode ultrasonography was assessed in the visualization and placement of the cannula tip, cranial to the entrance of the ovarian veins as they enter the caudal vena cava of the bovine. A cannula containing a wire guide was introduced into the coccygeal vein via a 14-gauge needle, and was then directed cranially into the caudal vena cava. Once the caudal vena cava was successfully cannulated (7 of 14 cows), ultrasonography allowed for the visualization of the cannula in 7 out of 7 cows. The tip of the cannula was successfully placed cranial to the entrance of the ovarian effuent into the vena cava in 6 of these 7 animals using ultrasound guidance. This was confirmed using progesterone or prostaglandin F(2alpha) radioimmunoassay (RIA). The primary limitation to this technique was the initial catherization of the coccygeal vein which was not achieved in 7 of 14 cows attempted in this study. Successful cannulation was limited to large framed Holstein cows that had at least one calf. Results from this study indicate that real-time, B-mode, ultrasonography is an effective tool for the visualization and accurate placement of the cannula tip within the caudal vena cava. This finding could have implications for research in ovarian hormonal physiology in the cyclic, postpartum or anestrous cow.     

A simple method for intragastric administration of powdered materials to rats

A simple technique was used for administration of powdered material directly into the stomach of rats. A commerically available positive displacement pipetting device was filled by tamping the cannula tip into the powder. The contents of the cannula could then be discharged into the stomach by insertion of the cannula via the esophagus. The device required only minor modifications prior to its use in this manner. The technique provided a means of accurate dosing of insoluble materials and eliminated the difficulties encountered in the oral administration of suspensions.     

Gynecomastia: suction lipectomy as a contemporary solution

Suction lipectomy is adapted for the correction of gynecomastia. Previous attempts using suction lipectomy for gynecomastia still required the use of sharp dissection for removal of the glandular breast tissue as well as excision of redundant skin. With this new technique, gynecomastia is corrected solely with the use of suction lipectomy. The technique is successful if the gynecomastia is due to excess fat or parenchymal hypertrophy. A 7-mm cannula is inserted first, to remove the adipose tissue. Then a 2.4-mm cannula is used to remove the glandular and ductal tissue. The 7-mm cannula is then reinserted to remove subareolar parenchyma and to make final contour adjustments. The surrounding subcutaneous tissue is easily undermined to avoid a saucer deformity and to allow for skin contraction. Patients return to full activities in 48 hours. A compressive garment is worn for 4 to 6 weeks. The results of 10 patients are discussed.     

自制滴水双套管持续负压引流技术应用于全胃切除术后的效果评价

目的：目前全胃切除术术后患者腹腔引流多数是放置普通单管引流,然而术后预防性放置滴水双套管的价值还存在争议。现对滴水双套管应用于全胃切除术后腹腔引流的效果进行系统评价。方法：选取我院2011年9月-2013年9月开腹全胃切除患者100例为研究对象,随机分为实验组和对照组,实验组术毕放置两根滴水双套管,左右各一根,对照组常规放置普通橡胶引流管两根,比较两组术后退烧药物应用次数,平均每日引流量,腹腔感染发生率,置管时间,术后平均住院时间,严重并发症发生率。结果：对照组50例患者中,有1例出现十二指肠残端瘘合并腹腔出血。1例切口感染,3例腹腔积液。实验组50例中,有1例出现胃食管吻合口瘘并切口感染。术后前7天应用退烧药物（体温超过38.5摄氏度时应用）的平均次数（1.85±1.10）d,差异有统计学意义（P〈0.05）。平均每日引流量（145.50±15.45）ml,差异有统计学意义（P〈0.05）。平均拔管时间（9.90±2.75）d,但差异无统计学意义（P〉0.05）。平均术后住院时间（13.98±2.09）d,差异有统计学意义（P〈0.05）,吻合口瘘发生率两组无差异。结论：对于全胃切除患者,术后预防性放置滴水双套管,可明显减轻术后腹腔积液产生的体温升高,缩短住院时间,有效防止腹腔感染的发生,虽不能降低严重并发症的发生率,但可以起到及时发现及时处理的作用,避免二次手术。值得在临床上推广。     

The effect of sampling technique on acid-base balance and other blood parameters in the sheep.

The effect of 4 sampling routines--venipuncture, intravenous cannula, intravenous cannula following the administration of a tranquiliser (xylidino dihydrothiazine hydrochloride), intravenous cannula following exercise--were compared. Blood pH and base excess values were similar after venipuncture and cannula sampling, but higher (P less than 0 with 05) after the administration of the tranquiliser and lower (P less than 3 with 05) following exercise. Blood haemoglobin, haematocrit and lactate levels followed this pattern, while plasma protein levels were similar for all treatments except after exercise, where they were higher (P less than 0 with 05). The recovery of various blood parameters to normal values after a period of exercise was also studied: acid-base balance had returned to near normal within 60 min, while haemoglobin and haematocrit levels had returned to normal within 10 min.     

The use of a silastic shield to protect an externalized biliary cannula

A simple shield made of a folded silastic sheet is described for the protection of the externalized portion of a permanent biliary cannula in rats. Advantages of this shield are its light weight, flexibility, transparency, and ease of resealing for repeated interruption of hepatobiliary circulation. Since the shield is positioned around rather than being a segment of the cannula, a single length of tubing can be used.     

Maintenance of silastic–teflon shunts for intermittent haemodialysis

The occurrence of infection in the tissues surrounding external arteriovenous shunts was studied and die important relationship of pyogenic infection to clotting was confirmed. The local application of fusidic add tulle and lanolin greatly reduced the occurrence of both infection and clotting and the need for cannula replacement.Urokinase used for declotting shunts when standard procedures had failed, restored blood flow whether dotting was related to infection or to local vascular factors. This treatment is not advised when clotting is associated with a local abscess, as it may make cannula replacement necessary. Severe local vascular factors, such as metastatic calcification, Raynaud''s phenomenon, and venous stenosis, may lead to poor blood flow, so that despite clot lysis elective cannula replacement or the creation of a subcutaneous arteriovenous fistula is required.     

Reformative cannula electrodes for His bundle electrogram recording in isolated rat hearts

His bundle electrogram (HBE) recording is an important method for the study of the atrioventricular conduction system. However, the current HBE recording methods in isolated animal hearts have some disadvantages, such as unstable recording due to the difficulty in fixing electrodes as a result of intense heart beat, the small amplitude of the His signal or the possibility to destroy the integrity of heart structure. To overcome these disadvantages, we designed and manufactured reliable, inexpensive and easy-made bipolar cannula electrodes, which combine the functions of Langendorff-perfusion aortic cannula and recording electrodes. With the cannula electrodes, the operation of HBE recording becomes easier and clearer; hence, more stable recordings can be obtained in isolated rat hearts.     

Characterization of In Vivo Dopamine Release as Determined by Brain Microdialysis After Acute and Subchronic Implantations: Methodological Aspects

Infusion of tetrodotoxin (TTX) through the dialysis membrane and perfusion with calcium-free Ringer solution (calcium depletion) were used to evaluate the dopamine release determined by in vivo brain dialysis. Several hours after implantation, the dopamine release recorded by the U-shaped cannula did not respond to calcium depletion and was only partly (approximately 50%) TTX dependent. The half-life of the TTX-independent dopamine overflow was determined to be 2 h. In contrast, when a transstriatal cannula was used, the dopamine output displayed calcium and TTX dependency. Differences in the dimensions of the two types of probes are a likely explanation for the observed effects. Twenty-four hours after implantation, both types of cannula fulfilled the criteria of calcium and TTX dependency. The results indicate that infusion of TTX-containing or calcium-free Ringer solution can be used to estimate the functional damage caused by the implantation of the cannula.     

Simplified surgical placement and stabilization methods for intracerebroventricular cannulas in rat lateral ventricles

Intracerebroventricular cannulation in rat models is an efficient tool for exploring the effects of substances directly injected into the CNS, bypassing the blood-brain barrier. Techniques for surgically securing the ICV cannula require a balance between ease of application and adequate stability. The authors tested several methods of lateral ventricle cannula stabilization, especially focusing on a comparison of cyanoacrylate gel to cranioplastic cement with an anchoring bone screw.