Unusual complications of ballooned feeding tubes

Percutaneous Endoscopic Gastrostomy (PEG) and Feeding Jejunostomy (FJ) with a Foley catheter are well-established techniques for providing long-term nutritional support. Mechanical complications of these procedures are well recognised. We report two unusual complications of feeding tubes related to the balloon. Patient 1: A 23 years old female cerebral palsy patient had a PEG tube changed to a ballooned gastrostomy tube. Following this she developed abdominal cramps, vomiting and later on haematemesis. Contrast study showed migration of the balloon causing pyloric obstruction and a small prepyloric ulcer. Partially deflating the balloon and pulling it back to the original position corrected this. Patient 2: A 39 years old male cerebral palsy patient with a Foley catheter feeding jejunostomy developed obstructive symptoms within 48 hours of surgery. The balloon was deflated repeatedly without resolution. The catheter was impossible to withdraw and irrigate. Contrast instilled via the balloon channel demonstrated that the catheter was significantly stretched and the balloon was in terminal ileum. The balloon was fully deflated and easily withdrawn to be replaced with uninflated Foley catheter. Enteral feeding was easily reestablished. If a patient with a ballooned feeding tube develops intestinal symptoms balloon complications should be suspected. Contrast study through the feeding channel or balloon inflation channel is useful in diagnosing tube related complication. The threshold for imaging should be low, particularly in patients who are difficult to assess clinically.     

A modified guidewire technique for deflating a non-deflating Foley catheter in the emergency department

Abstract

Stuck catheter due to a non-deflating balloon is one of the complications of urinary catheters and these patients usually seek visits in the emergency department. The guidewire technique for deflating the balloon of a stuck Foley catheter is easy and non-invasive. But due to the characteristics of the guidewire in some instances, it could not be passed through the tight and narrow inflation port of the Foley catheter and the procedure would be frustrating for the physician and the patient. We made a modification that was successful in a case series of 8 male patients and made further invasive steps (rupture of the balloon by suprapubic or transrectal puncture) unnecessary.     

Tensile set behavior of Foley catheter balloons

The removal of indwelling urinary balloon catheters from patients is usually associated with many problems. The problems such as balloon deflation failure; encrustations on balloons, eyes, and lumen; and catheter associated infections are widely discussed in the literature. The tensile set exhibited by the catheter balloon material could also play a role and further complicate the removal process. This article addresses this issue by comparing the tensile set behavior of the balloon material from three commercially available Foley catheters. The balloon materials were subjected to aging in synthetic urine at 37 degrees C for 28 days to simulate clinical conditions. The deflation time of catheter balloons aged in similar conditions were also measured. It was found that different brands of catheters exhibited statistically significant differences in their properties. The tensile set data of the aged samples could be correlated with the deflation time of the balloons. The clinical significance of the tensile set is also highlighted.     

AT2R基因在体转染抑制大鼠颈动脉新生内膜增生

目的: 探讨AngⅡ 2型受体（AT2R）基因在体转染对大鼠颈动脉球囊损伤后新生内膜增生的抑制作用。方法:大鼠颈动脉球囊损伤后，局部转染AT2R重组腺病毒载体（pAdCMV/AT2R）或空病毒载体（pAd-GFP），于术后7、14和21 d用RT-PCR、免疫组织化学及HE染色方法，进行AT2R、AngⅡ 1型受体(AT1R)、PCNA在颈动脉壁中表达的变化及定量组织形态学分析；免疫荧光双标染色和激光共聚焦技术检测血管中AT2R与PCNA表达的关系。结果: pAdCMV/AT2R转染后，大鼠颈动脉AT2R的表达水平显著高于未转染组和pAd-GFP组(P<0.01)，21 d时仍维持较强表达。在14 d时pAdCMV/AT2R组PCNA阳性表达率显著低于未转染组和pAd-GFP组［(27.29±5.81)% vs ( 72.25±4.47)%、(68.43±9.12)%，P<0.01］，在AT2R表达阳性的部位PCNA表达阴性。在21 d时，pAdCMV/AT2R组的内膜面积与中膜面积比显著低于未转染组和pAd-GFP组(0.78±0.06 vs 1.44±0.22、1.36±0.21, P<0.01)，pAd-GFP组和未转染组间无显著差异（P>0.05）；各组颈动脉AT1R表达水平无显著差异(P>0.05)。结论: AT2R基因在体转染可抑制球囊损伤后大鼠颈动脉平滑肌细胞增殖和新生内膜增生，AT2R基因转染后表达并发挥其生物学作用时，AT1R和AT2R之间不存在表达量上此起彼伏的关系，可能是建立在信号转导基础上的功能调节关系。     

Influence of hyperthermia on carotid blood flow using <Superscript>99m</Superscript>Tc-HMPAO

Hyperthermia can be the result of many causes such as environmental conditions, brain tumors and infectious diseases. Since hyperthermia is very common, its role in causing stroke through a decrease in cerebral blood flow needed further emphasis. The aim of this study was to record cerebral blood flow in vitro by using isolated rabbit carotid artery strips and in-vivo using radioactive isotope scanning during temperature elevation. The recording of isometric tension in rabbit carotid artery strips in organ baths, and the scintigraphic cerebral imaging of technetium-99m-hexamethyl-propyleneamineoxime (99mTc-HMPAO) using Gamma camera, were acquired at control and higher body temperature by 4°C. Blood pressure was measured through femoral artery and cerebral blood flow was measured through carotid artery. Elevating temperature by 4°C induced reproducible contraction. During hyperthermia, the carotid artery contraction leads to a decrease in cerebral blood flow although the blood pressure did not decrease. The uptake of 99mTc-HMPAO in the brain was significantly reduced. This decrease in cerebral perfusion is regionally dependent, which is more in the frontal area, the cerebral hemispheres than the cerebellum. The decrease was 36 ± 3, 37 ± 2, 22 ± 2%, respectively. Hyperthermia causes carotid artery contraction leading to decrease in cerebral blood flow, which was confirmed by 99mTc-HMPAO images. The decrease is regionally dependent. Since the blood pressure did not decrease by heating, the reduction in cerebral perfusion is mainly due to carotid contraction. The applied neck cooling may be considered as a promising therapeutic strategy for the hyperthermic patient to avoid brain damage. This can be achieved by external application of an ice-water-perfused neck collar.     

Atrial natriuresis under the condition of a constant renal perfusion pressure

An experimental elevation of left atrial pressure (eLAP ↑) by means of a reversible mitral stenosis is accompanied with an increase in sodium excretion (UNa—) and arterial blood pressure (by about 20 mm Hg, 2.7 kPa), and by a decrease in plasma renin activity. It is well established that an increase in renal perfusion pressure (Pren) can augment UNa—. Therefore the present study was undertaken to examine whether the eLAP ↑-induced natriuresis was caused by the increased Pren. — Four female beagle dogs were kept under controlled environmental conditions. They received asodium rich diet (14.5 mmol/Na/kg/d). The dogs were chronically instrumented: purse string around the mitral annulus, catheter in the left atrium, carotid loop, pneumatic cuff above the renal arteries, pressure transducer below the renal arteries. Pren was kept constant by means of a digital servofeedback control circuit. The dogs served as their own controls (13 experiments without and 15 experiments with a controlled renal perfusion pressure were performed). After eLAP↑(+1.0 kPa), UNa— rose from 4.1±2.6 to 10.3±3.9 μmol Na/min/kg. If Pren was kept constant, the corresponding values were 4.2±2.8 and 9.3±2.9 μmol/min/kg. These data clearly indicate that the atrial natriuresis is not mediated by an augmentation of renal perfusion pressure. Therefore these results support the hypothesis that atrial natriuresis probably is due to an eLAP↑-induced suppression of the renin-angiotensin-system or other natriuretic mechanisms.     

Simulation study of a selective cerebral perfusion system with a single centrifugal pump

We previously successfully developed a simple nonroller extracorporeal circulation system (NRECC). In aortic arch surgery, more than two pumps are generally used for systemic perfusion and selective cerebral perfusion (SCP); we developed a new pressure-dependent perfusion system for SCP based on our NRECC and operated by a single centrifugal pump. The cerebral perfusion line was branched from the main perfusion line, and one 15 French and two 12 French cannulae were used for SCP. The perfusion pressure was regulated with a tube occluder. Afterload was changed from 30 to 80 mm Hg, the pressure of the SCP line was increased from 80 to 200 mm Hg, and flow volume was measured. When the afterload was set at 50 mm Hg, according to the increase of perfusion from 80 to 200 mm Hg, the flow volume of the 15 French cannula increased from 280 to 950 ml/min. Under the same conditions, flow volume of the 12 French cannula increased from 160 to 560 ml/min. Sufficient flow volume of the SCP lines was obtained when the SCP line pressure was over 80 mm Hg. As a result of the increased perfusion pressure, the flow volume showed a direct increase. These findings suggest that aortic arch surgery is possible using this SCP system.     

Urinary catheters: history,current status,adverse events and research agenda

Abstract

For more than 3500 years, urinary catheters have been used to drain the bladder when it fails to empty. For people with impaired bladder function and for whom the method is feasible, clean intermittent self-catheterization is the optimal procedure. For those who require an indwelling catheter, whether short- or long-term, the self-retaining Foley catheter is invariably used, as it has been since its introduction nearly 80 years ago, despite the fact that this catheter can cause bacterial colonization, recurrent and chronic infections, bladder stones and septicaemia, damage to the kidneys, the bladder and the urethra, and contribute to the development of antibiotic resistance. In terms of medical, social and economic resources, the burden of urinary retention and incontinence, aggravated by the use of the Foley catheter, is huge. In the UK, the harm resulting from the use of the Foley catheter costs the National Health Service between £1.0–2.5 billion and accounts for ～2100 deaths per year. Therefore, there is an urgent need for the development of an alternative indwelling catheter system. The research agenda is for the new catheter to be easy and safe to insert, either urethrally or suprapubically, to be retained reliably in the bladder and to be withdrawn easily and safely when necessary, to mimic natural physiology by filling at low pressure and emptying completely without damage to the bladder, and to have control mechanisms appropriate for all users.     

Middle cerebral artery blood velocity during rowing

Dynamic exercise increases the transcranial Doppler determined mean blood velocity in basal cerebral arteries corresponding to the cortical representation of the active limb(s) and independent of the concomitant rise in the mean arterial pressure. In 12 rowers we evaluated the middle cerebral artery blood velocity response to ergometer rowing when regulation of the cerebral perfusion is challenged by stroke synchronous fluctuation in arterial pressure. Rowing increased mean cerebral blood velocity (57 ± 3 to 67 ± 5 cm s^?1; mean ± SE) and mean arterial (86 ± 6 to 97 ± 6 mmHg) and central venous pressures (0 ± 2 to 8 ± 2 mmHg; P < 0.05). The force on the oar triggered an averaging procedure that demonstrated stroke synchronous sinusoidal oscillations in the cerebral velocity with a 12 ± 2% amplitude upon the average exercise value. During the catch phase of the stroke, the mean velocity increased to a peak of 88 ± 7 cm s^?1 and it was in phase with the highest mean arterial pressure (125 ± 14 mmHg), while the central venous pressure was highest after the stroke (20 ± 3 mmHg). The results suggest that during rowing cerebral perfusion is influenced significantly by the rapid fluctuations in the perfusion pressure.     

选择性深低温血流阻断猴海马超微结构和波形蛋白表达的变化**

背景：前期研究显示,选择性深低温顺行脑灌注能提高猴脑对缺血缺氧的耐受性。 目的：观察选择性深低温血流阻断对猴海马超微结构和波形蛋白表达的影响。 方法：将8只健康成年恒河猴随机分为两组：深低温组(n=5)在常温下阻断猴双侧颈总动脉及颈内静脉10 min,然后通过一侧颈内动脉灌注4 ℃林格氏液,同侧颈内静脉回流,使脑温维持在18 ℃以下,60 min后恢复脑血流;常温组(n=3)除灌注液改为37 ℃林格氏液外,其余与深低温组相同。 结果与结论：深低温组猴全部成功复苏,海马组织形态及超微结构未见明显异常。常温组猴全部死亡,未能成功复苏,海马组织形态及超微结构有不同程度异常。与常温组比较,深低温组海马波形蛋白表达显著降低(P < 0.01)。说明阻断双侧颈总动脉10 min后行选择性深低温顺行脑灌注可下调海马波形蛋白表达,保护海马组织,减轻脑缺血损害。     

Local enzymatic treatment of atherosclerotic plaques

Fat rich and fibromuscular lesions experimentally induced in animals as well as human atherosclerotic plaques were locally digested enzymatically with the help of a newly developed double balloon catheter. The technique was most successful if applied to fat rich intimal proliferation of hypercholesterolemic rabbits, while the fibromuscular plaques of dog femoral arteries and of human common carotid arteries were less sensitive to the treatment. Osmotic or denaturing pretreatments increased the efficiency of the different proteolytic enzymes. Thrombotic complications and leukocytic infiltration developed in dogs surviving the enzymatic digestion by 2 days. A perfect enzymatic dissolution of the fibromuscular plaques was not achieved but the enzymatic digestion appeared to offer the organism a chance to complete the dissolution by its own means. The passive mechanical properties of the treated human carotid arteries changed favorably. The technique requires skill and a competent background in vascular surgery. Nonetheless the local enzymatic treatment might serve either as an adjunct to angioplasty or as an alternative treatment.     

Interventional MRI‐guided local delivery of agents into swine bile duct walls using MR‐compatible needle‐integrated balloon catheter system

The purpose of this study was to investigate the feasibility of interventional MRI‐guided local agent delivery into pig common bile duct (CBD) walls using a newly designed MR‐compatible, needle‐integrated balloon catheter system. We first designed a needle‐integrated balloon catheter system that comprised of a 22 G MR‐compatible Chiba biopsy needle and a conventional 12 mm × 2 cm balloon catheter. Under fluoroscopy guidance, a custom needle–balloon system was positioned in the target CBD via a transcholecystic access. T₁‐weighted MRI was used to localize and reposition the needle–balloon system in the target. A 0.5 mL mixture of motexafin gadolinium (MGd) and trypan blue dye as well as 5‐fluorouracil was delivered into the CBD wall through the needle–balloon system. Post‐infusion T₁‐weighted MRI was obtained and contrast‐to‐noise ratios (CNRs) of CBD walls of pre‐ and post‐MGd–blue infusions were compared by a paired t‐test. In addition, post‐infusion x‐ray cholangiography was achieved to evaluate the potential injuries of CBDs by the needle–balloon system. Subsequent histologic analysis was performed to correlate and confirm the imaging findings. A post‐infusion cholangiogram did not show any extravasation of contrast agent, indicating no procedure‐related damage to the CBDs. MRI demonstrated clear enhancement of the target bile duct walls infused with MGd–trypan blue dye with average penetration depth of 4.7 ± 1.2 mm and an average MGd perfusion length of 21 ± 1.5 mm in the bile ducts and their surrounding tissues. The average CNR of the post‐infusion bile ducts was significant higher than that of the pre‐infusion bile ducts (110.6 ± 22 versus 5.7 ± 2.8, p < 0.0001). Histology depicted the blue dye staining and red fluorescence of MGd through the target CBD walls, which was well correlated with the imaging findings. It is feasible to use the new MR‐compatible, needle‐integrated balloon catheter system for intrabiliary local agent delivery into CBD walls under MRI guidance, which may open new avenues for efficient management of pancreatobiliary malignancies using MR‐guided interventional oncology. Copyright © 2015 John Wiley & Sons, Ltd.     

The hemodynamic effect of bilateral carotid artery ligation and the morphometry of the main communicating circuit in normotensive and spontaneously hypertensive rats

After reducing the number of patent conduit arteries to the brain by bilateral ligation of the carotid artery, the percentage decrease in blood pressure from the aorta to the internal carotid artery distal to the ligation was larger in spontaneously hypertensive rats than in normotensive rats. The pressure drop corresponded to the degree of hypertension as well as to morphometrically determined structural arterial alteration in the main communicating circuit, i.e. larger media to internal radius ratio and smaller internal radius in the posterior communicating arteries, the proximal part of the posterior cerebral arteries, the basilar artery and the vertebral arteries. The discrepancy between the sum of the luminal cross sectional areas of the communicating circuit and the luminal areas of the ligated conduit arteries was larger in the hypertensive than in the normotensive rats. It is to be expected that occlusion of conduit arteries to the brain will have a larger impact on the cerebral arterial perfusion pressure head in the presence of such hypertensive structural alterations known to increase flow resistance.     

Effect of adrenergic blockade on autoregulation of the cerebral blood flow during orthostatic tests

In experiments on rats under local anesthesia the action of phentolamine and propranolol on autoregulation of the cerebral blood flow (ACB) was studied during orthostatic tests (OT). The cerebral blood flow was measured in the carotid system, the venous pressure in the cerebral vessels, and the perfusion pressure in the carotid arteries; the resistance of the cerebral vessels was calculated. OT were simulated by tilting a special table with the animal (head upward or downward) through 40–80° from the horizontal plane. The results showed that adrenergic blockade in most cases of OT disturbed ACB: phentolamine led to a passive increase in the cerebral blood flow in response to an increase in perfusion pressure, whereas propranolol, on the other hand, caused a passive decrease in the cerebral blood flow in response to a fall of perfusion pressure.Department of Pharmacology, Pyatigorsk Pharmaceutical Institute. (Presented by Academicaian of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 9, pp. 309–311, September, 1978.     

"All in one" cardiopulmonary bypass circuit for aortic surgery

We devised an "all in one" cardiopulmonary bypass circuit for aortic surgery, and evaluated its efficacy and safety. The circuit consisted of a venous line, reservoir, single centrifugal pump, membrane oxygenator and arterial line bifurcated into two lines for systemic perfusion and selective branch perfusion. The perfusion volume was regulated by an occluder and measured by a flow sensor. A closed partial bypass was established using a shunt line bypassing the reservoir. We applied this circuit to 25 patients with aortic disease. Regulation of both the selective cerebral perfusion (SCP) and the selective branch perfusion was easily performed. There was neither stroke nor organ dysfunction postoperatively. There are some cases in which it is difficult to decide the necessity for SCP preoperatively; the use of this circuit may resolve this problem. This circuit can be easily and safely applied to any type of aortic surgery.     

Pressure/flow relation in the peripheral pulmonary vascular bed in dogs: a preliminary study

In order to test a technique for the determination of the pressure/flow relationship in the peripheral pulmonary vascular bed, the perfusion pressure changes with increasing and then decreasing flow in a small part of the lung (around 1 ml) were studied in anaesthetized supine dogs, after insertion of a specially designed double distal lumen Swan–Ganz catheter. One lumen was used for the pressure measurement, one for infusion of saline by a pump with variable flow, from 0.1 to 1.0 ml s^-1. A conventional thermodilution Swan–Ganz catheter was also advanced in the pulmonary artery, to measure pressures in the pulmonary circulation as well as cardiac output. During infusion in the wedged catheter, right atrial, pulmonary arterial and balloon occlusion wedge pressures did not change. The pressure/flow curve of the occluded vascular bed showed a shape similar to that of collapsible tubes, with a pressure plateau at high flow, but this could also be due to vascular recruitment. The curve exhibited hysteresis, with a lower pressure when flow decreased. The slope of the initial part of the curve increased, on average, from 54±9 during normoxia to 91±27 mmHg s ml^-1during hypoxia (FIO₂= 0.10); this difference was not significant, but the perfusion pressure at high flow was significantly higher during hypoxia (P < 0.05). Using blood instead of saline would allow the determination of the peripheral pulmonary vascular resistance under physiological conditions, and further work is needed to estimate the sensitivity and the reproducibility of this technique.     

Retinal ischemia induced by occlusion of both common carotid arteries in rats as demonstrated by electroretinography.

In 2 models of reduced cerebral blood flow-permanent occlusion of the vertebral arteries plus transient occlusion of the common carotid arteries (4VO) and transient clamping of the common carotid arteries (BCCA)-the acute effects on the electrical function of the retina were monitored by recording the photopic electroretinogram. During both 4VO and BCCA the amplitude of the b-wave was reduced. Within 30 min of reperfusion after 4VO and after BCCA the b-wave had fully recovered. In contrast, the a-wave was not affected by either treatment. The data suggest that occlusion of common carotid arteries leads to retinal ischemia and might represent a useful model of amaurosis fugax.     

A newly developed cerebral perfusion catheter for aortic arch operation

The object of this study was to develop a better catheter for selective cerebral perfusion during aortic arch operation. Flow through the catheter was evaluated in an in vitro study under 40 mmHg pressure at 25°C using 40% glycerin when the catheter was straight or right-angled with either a gentle or a sharp curve. Two catheters of 14, 16, or 18 French were connected with a Y-shaped tube, and the flow through each catheter was tested in the same way when the catheters were straight or right-angled. Moreover, we evaluated the operative outcome using this new catheter in 38 patients who underwent total arch replacement. The correlation between right radial artery pressure and catheter tip pressure was examined in 17 of these 38 patients. The difference in oxygenation between the right and left hemispheres was also exmained by two-channel nearinfrared spectroscopy. The results showed that flow through the catheter was almost identical, regardless of the type of its configuration. When two catheters of different sizes were connected with a Y-shaped tube, the total flow and flow ratio between the two catheters were also similar in both the straight and the right-angled configuration. As regards the clinical outcome, there were no in-hospital deaths, no permanent neurological dysfunction, and one temporary neurological dysfunction. Dissociations between right radial artery pressure and catheter tip pressure were seen in 3 of the 17 patients. No difference in oxygenation between the two hemispheres was found. We conclude that the new catheter provided an uncluttered operative field and may contribute to improved surgical results.     

Global cerebral blood flow during infusion of adenosine in humans: assessment by magnetic resonance imaging and positron emission tomography

Adenosine, an endogenous vasodilator, induces a cerebral vasodilation at hypotensive infusion rates in anaesthetized humans. At lower doses (< 100 μg kg^?1 min^?1), adenosine has shown to have an analgesic effect. This study was undertaken to investigate whether a low dose, causing tolerable symptoms of peripheral vasodilation affects the global cerebral blood flow (CBF). In nine healthy volunteers CBF measurements were made using axial magnetic resonance (MR) phase images of the internal carotid and vertebral arteries at the level of C2–3. Quantitative assessment of CBF was also obtained with positron emission tomography (PET) technique, using intravenous bolus []> ¹⁵O]butanol as tracer in four of the subject at another occasion. During normoventilation (5.4 ± 0.2 kPa, mean ± s.e.m.), the cerebral blood flow measured by magnetic resonance imaging technique, as the sum of the flows in both carotid and vertebral arteries, was 863 ± 66 mL min^?1, equivalent to about 64 ± 5 mL 100 g^?1 min^?1. The cerebral blood flow measured by positron emmission tomography technique, was 59 ± 4 mL 100 g^?1 min^?1. All subjects had a normal CO₂ reactivity. When adenosine was infused (84 ± 7 μg kg^?1 min^?1) the cerebral blood flow, measured by magnetic resonance imaging was 60 ± 5 mL 100 g^?1 min^?1. The end tidal CO₂ level was slightly lower (0.2 ± 0.1 kPa) during adenosine infusion than during normoventilation. In the subgroup there was no difference in cerebral blood flow as measured by magnetic resonance imaging or positron emission tomography. In conclusion, adenosine infusion at tolerable doses in healthy volunteers does not affect global cerebral blood flow in unanaesthetized humans.