Serial determinations of oxygen profiles in infants with respiratory distress.

Serial oxygen profiles were determined for 20 newborn infants by measuring arterial tensions at low (20--40%), intermediate (60--80%), and high (95--100%) levels of inspired oxygen. These points were plotted on a graph which estimated the percentage of venous admixture at any particular level of inspired oxygen. The infants'' oxygen profiles were then determined. As much as 25% of venous admixture could be attributed to the presence of diffusion and distribution abnormalities in infants with hyaline membrane disease. A substantial number of infants showed increased shunting at high levels of oxygen, even in the presence of continuous distending airway pressure. It is hypothesised that a rising shunt is due to complete absorption of gas in poorly ventilated alveoli at high concentrations of inspired oxygen, resulting in the presence of atelectasis and redistribution of blood to poorly ventilated areas.     

Cerebral blood flow velocity in term newborn infants: changes associated with ductal flow

The effects of ductal closure on range-gated pulsed Doppler cerebral blood flow velocity (CBFV) patterns in the internal carotid, anterior cerebral, and middle cerebral arteries were studied in 10 normal term infants (mean birth weight 3302 +/- 294 g (SD) and mean gestational age 39.6 +/- 1.3 weeks). Pulsatility was calculated from flow velocities and used as an estimate of cerebral blood flow (CBF). Ductal closure was associated with a rise in mean blood pressure from 45.0 +/- 4.2 to 51.3 +/- 6.5 mm Hg (P less than 0.05) and a significant decrease in pulsatility in all three vessels (mean = 0.77 +/- 0.07 vs 0.70 +/- 0.05 (P less than 0.02]. Changes in pulsatility were correlated with changes in mean blood pressure (P less than 0.02), providing evidence that systemic blood pressure may influence postnatal cerebral arterial pulsatility indices. We also noted significant differences in the velocity and pulsatility of individual vessels that were independent of blood pressure, suggesting that Doppler flow studies may be useful in describing regional CBF patterns. The temporal association between ductal closure and decreased pulsatility suggests that CBFV patterns reflect ductal shunting in normal term newborn infants. Diastolic runoff and reduced systemic blood pressure in the presence of ductal shunting appear to reduce diastolic flow velocity and increase CBFV pulsatility in normal term infants during the first days of life. Normal mechanisms of cerebral autoregulation compensate for decreased flow with vasodilation; therefore the increased pulsatility associated with ductal shunting may be due to diastolic runoff rather than increased cerebrovascular resistance.     

Bidirectional shunt flow across a ventricular septal defect: Pulsed doppler echocardiographic analysis

Pulsed Doppler echocardiographic and hemodynamic examinations were performed in 31 patients (mean age 17.8 years) with isolated ventricular septal defect (VSD). Three groups were studied: group I (n=6) patients had severe pulmonary vascular obstructive disease (PVOD); group II (n=12) patients had pulmonary hypertension (PH) without severe PVOD; group III (n=13) patients had no PH. Bidirectional shunting was detected in 9 VSD patients (6 in group I and 3 in group II). Patients with low to moderately elevated right ventricular pressures demonstrated left-to-right shunting across the defect throughout the cardiac cycle. When systolic pressure in the right ventricle reached approximately 60% of the left ventricular pressure, right-to-left shunting occurred across the defect during early and mid diastole. However, in patients with Eisenmenger syndrome (group I) the right-to-left shunting occurred during late systole with continuation during the early and mid diastolic period. The earlier occurrence of right-to-left shunting (index <0.5 second) signifies the presence of severe PVOD.     

Shunt dependency in shunted arachnoid cyst: a reason to avoid shunting

Cystoperitoneal (CP) shunting is minimally invasive and achieves a high rate of resolution on neuroimaging. However, in the absence of definite symptoms, shunting should be reconsidered, because some patients can experience shunt dependency after CP shunting. In this study, the risk of shunt dependency in patients with arachnoid cysts treated with CP shunting and the management of these patients are described. Eight patients (7 boys and 1 girl) were diagnosed as shunt dependent following CP shunting. At the time of the first operation (mean age at first shunting 6.1 years, range 1-11 years), a causal relationship between symptoms and the arachnoid cyst was evident in only 2 cases. Clinical manifestations, neuroimaging (computed tomography and/or magnetic resonance imaging) and intracranial pressure (ICP) data were reviewed retrospectively. The mean age of the patients at the time of shunt dependency was 9.8 years (range 6-13 years), and the mean time between the first shunt operation and shunt dependency was 41 months (range 17-80 months). Although neuroimaging demonstrated a collapsed cyst and small ventricles in most patients, ICP monitoring revealed significant intracranial hypertension. The release of shunt ligation, revision or additional shunting, such as ventriculoperitoneal shunting or lumboperitoneal shunting, resulted in the complete resolution of symptoms except in one patient who lost vision. This study shows that shunt dependency after CP shunting is a real problem and requires more attention. ICP monitoring can demonstrate the presence of intracranial hypertension when clinical and radiological analyses do not.     

Aerosolised prostacyclin for pulmonary hypertension in neonates.

Aerosolised prostacyclin (PGI2) was administered to two neonates with pulmonary hypertension to dilate the pulmonary vessels selectively. The alveolar-arterial oxygen gradient fell from 73.2 (patient 1) and 71.8 kPa (patient 2) to 33.8 and 26.7 kPa respectively. Systemic blood pressure remained stable while pulmonary blood pressure declined in patient 1. When inhaled, PGI2 seems to improve oxygenation, mainly due to reduction of intrapulmonary shunting.     

Transcatheter Closure of Abnormal Vessels and Arteriovenous Fistulas With the Amplatzer Vascular Plug 4 in Patients With Congenital Heart Disease

Although vascular plugs allow the interventional closure of medium-sized to large abnormal vessels, their application is limited by the need for long sheaths or large guiding catheters. The authors report their experience with the new Amplatzer vascular plug 4 (AVP 4), a self-expanding spindle-shaped occluder made of Nitinol wire mash, which can be placed through 4-Fr catheters with an internal diameter of 0.038 in. or larger. From October 2009 until June 2012, 14 AVP 4 devices were deployed in 12 patients (ages, 0.3–48.8 years). Nine patients had venovenous or arteriovenous collaterals in functional univentricular hearts. One patient had pulmonary atresia with a ventricular septal defect and major aortopulmonary collateral arteries, and one patient had a pulmonary arteriovenous fistula. One child had a large coronary artery fistula to the right atrium. The authors used AVP 4 devices with diameters of 4–8 mm. In all the patients, the AVP 4 was implanted successfully. No occluder dislocations and no complications related to the procedure occurred. Complete vessel occlusion was achieved in seven cases. In seven additional cases, a residual shunt was present at the end of the procedure while the patients were still fully heparinized. In 2 of 14 vessels, the decision was made to place additional devices to abolish residual shunting. According to the authors’ experience, the AVP 4 allows safe and effective occlusion of medium-size and large abnormal vessels. It is also well suited for tortuous high-flow vessels such as coronary or pulmonary arteriovenous fistulas. In case of a suboptimal position, it is possible to reposition the occluder with ease. Further studies are needed to determine whether initial residual shunting in heparinized patients disappears during follow-up care. The AVP 4 represents a valuable new device for the interventional treatment of complex congenital vessel malformations.     

Idiopathic dilation of the ductus venosus: an unusual anomaly of the fetal blood vessels

The ductus venosus (DV) is a blood vessel unique to the fetal circulation. It functions as a shunt between the umbilical vein and inferior vena cava by passing the hepatic microcirculation and shunting highly oxygenated blood to the brain and myocardium. The DV has received less attention than the ductus arteriosus; however, with modern ultrasonographic imaging, the DV is easily identified and is becoming a valuable diagnostic tool in the areas of maternal-fetal medicine. We report a rare case of idiopathic dilation of the DV that was diagnosed during routine ultrasounds. The presence of blood flow turbulence within the dilated area and the concern that blood vessels might rupture resulted in elective cesarean section at 34 weeks gestation. The infant was discharged after 14 days. Dilation of the DV, its size as well as the presence of turbulence in the dilated area might be important factors in determining the time of delivery and could contribute to a better outcome.     

Early determinants of right and left ventricular output in ventilated preterm infants.

One hundred and twenty ventilated preterm infants, birthweight < 1500 g, were examined within the first 36 hours with colour Doppler echocardiography, to determine the cardiorespiratory influences on right (RVO) and left ventricular output (LVO). Forty nine of these infants had three further daily scans. Measurements included left ventricular (LV) ejection fraction, Doppler determination of RVO and LVO, and ductal and interatrial shunt direction, velocity and colour Doppler diameter. Infants were grouped by respiratory disease severity: mild, mean FIO2 in first 24 hours < 0.5; moderate/severe, mean FIO2 < 0.5; and fatal, death resulting directly from acute respiratory distress. In the early studies ventricular outputs varied widely (RVO: 62-412 ml/kg/minute, LVO: 75-505 ml/kg/minute). The incidence of low ventricular outputs (< 150 ml/kg/minute) increased with worsening respiratory disease. The incidence of low RVO in the mild group was 19%, in the moderate/severe group 42%, and in the fatal group 85%. More infants had a low RVO than a low LVO, reflecting the impact of ductal shunting. Ductal and atrial shunting was predominantly left to right except in those with fatal respiratory disease. In those studied longitudinally, RVO and LVO increased with age and low outputs were not seen after day 3. Multilinear regression analyses, with RVO as the dependent variable, revealed increasing LVO and atrial shunt diameter as significant positive influences and increasing ductal shunt diameter and mean airway pressure as a significant negative influence. With LVO as the dependent variable, increasing RVO, ductal shunt diameter, and age were significant positive influences and increasing atrial shunt diameter was a significant negative influence. Low ventricular outputs are more common with worsening respiratory disease. Mean airway pressure and ductal shunting are two negative influences on ventricular outputs over which there is some therapeutic control.     

Antecedents of periventricular haemorrhage in infants weighing 1250 g or less at birth.

Fifty infants who weighed 1250 g or less at birth were studied with serial real time cerebral ultrasound to evaluate the temporal relation of various perinatal factors to the onset and progression of periventricular haemorrhage (PVH). The significant antecedents of PVH were severe bruising at birth, low birthweight, short gestation, ratio of arterial oxygen pressure (PaO2) to fractional inspired oxygen (FiO2), and haematocrit on admission, hyaline membrane disease, assisted ventilation, pneumothorax, administration of tubocurarine, hypercapnia, hypoxaemia, and hypotension. Case control studies, in which infants with PVH at 26 weeks'' and 28 weeks'' gestation were compared with matched infants without PVH, confirmed that the antecedents identified were independent of gestational influences. A multivariate discriminant analysis for the antecedents of PVH showed that hyaline membrane disease, hypercapnia, and short gestation correctly classified presence or absence of PVH in 78% of the study group. A similar analysis comparing infants with germinal layer haemorrhage or intraventricular haemorrhage with those who developed intracerebral extension of haemorrhage showed that three factors found on admission (hypothermia, a low PaO2:FiO2 ratio, and severe bruising) combined to classify correctly 90% of the haemorrhages. Our data suggest that prevention of perinatal trauma and asphyxia as well as respiratory illness, especially hyaline membrane disease, and stabilisation of blood gas tensions, blood pressure, and haematocrit within the physiological range, are likely to be the most effective ways of preventing PVH in extremely preterm infants.     

The value of colour Doppler ultrasonography for identification of crossing vessels in children with pelvi-ureteric junction obstruction

Background Pelvi-ureteric junction (PUJ) obstruction is caused by the presence of an aperistaltic dysplastic segment at the PUJ. Besides this intrinsic aetiology, extrinsic abnormalities, mainly crossing vessels, may be an associated factor.Objective To determine the reliability of colour Doppler US in the detection of crossing vessels in children with surgically proven PUJ obstruction.Materials and methods Forty-eight patients (50 kidneys) with PUJ obstruction, surgically treated from 1998 to 2001, were prospectively studied by colour Doppler US prior to open pyeloplasty. There were 33 boys and 15 girls (age 2 months—12 years; median 3.5 years). There were 24 right kidneys and 26 left kidneys. The indication for surgery was according to the usual criteria. The crossing vessel was considered as present when depicted on colour Doppler US at the PUJ.Results Colour Doppler assessment of the crossing vessels was correct in all but two patients. At surgery, a crossing vessel was found in 14 kidneys (i.e. 28%). Colour Doppler US results were correlated with intra-operative findings in 50 renal units. Surgically proven vessels in 14 kidneys were identified by colour Doppler US in 13, and not shown in 1. In PUJ obstruction without a crossing vessel (n=36), US findings were concordant in 26, discordant in 8 and inconclusive in 2 (with kidney malrotation) cases. Colour Doppler US had a sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy of 92.8%, 76.5%, 62%, 96.3% and 78%, respectively. The reliability of colour Doppler US was greatly improved with the increasing experience of the sonographer, as shown by the results of the last 2 years (26 kidneys):Se=100%, Sp=87.5%, PPV=81.8%, NPV=100%, accuracy=88.5%.Conclusions Colour Doppler US is reliable in the detection of crossing vessels at the PUJ.Presented at the 39th Annual Congress of ESPR, Bergen, Norway, June 2002     

Lumbar CSF shunting preferentially drains the cerebral subarachnoid over the ventricular spaces: implications for the treatment of slit ventricle syndrome

Based on a proposed pathophysiology of slit ventricle syndrome (SVS), we have hypothesized that lumboperitoneal shunting exerts effects in SVS patients by increasing the buffering capacity for raised intracranial pressure (ICP) via an increase in cerebrospinal fluid drainage from the cerebral subarachnoid space (SAS). We describe 3 SVS patients with patent lumbar subarachnoid drainage but under-functioning ventriculoperitoneal shunts (VPS) who presented with ventriculomegaly (not SVS), and persistence of shunt malfunction like symptoms. Revision of the VPS resulted in complete resolution of symptoms despite a finding of low pressure in the ventricular space. This supports the hypothesis that lumboperitoneal shunting preferentially drains the SAS over the intraventricular space and in these cases allows the 'SVS' ventricles to enlarge by creating a pressure gradient from ventricles to SAS through the cortical mantle.     

Lumboperitoneal shunting as a treatment for slit ventricle syndrome

OBJECTIVE: Slit ventricle syndrome (SVS) has been described in hydrocephalus patients who continue to have shunt malfunction-like symptoms in the presence of a functioning shunt system and small ventricles on imaging studies. These symptoms usually present years after shunt placement or revision and can consist of headache, nausea and vomiting, lethargy and decreased cognitive skills. Treatments offered range from observation, medical therapy (migraine treatment) and shunt revision to subtemporal decompression or cranial vault expansion. We describe a subset of patients with SVS who were symptomatic with high intracranial pressure (ICP) as measured by sedated lumbar puncture and whose symptoms completely resolved after lumboperitoneal shunt (LPS) placement. METHODS: Seven patients with a diagnosis of SVS underwent lumboperitoneal shunting. The age at shunting ranged from 3 to 18 years. Most had undergone recent ventriculoperitoneal shunt (VPS) revisions for presentation of shunt malfunction-like symptoms. Despite this, all remained symptomatic and underwent a sedated lumbar puncture to measure opening pressure (OP). All had high OP in spite of a functional VPS and underwent LPS placement. RESULTS: All 7 patients had a prolonged period of overdrainage symptoms after lumboperitoneal shunting that resolved completely over several weeks. The initial etiology of hydrocephalus was reported to include trauma, aqueductal stenosis and intraventricular hemorrhage of prematurity. Two patients required revision of their LPS, after which their symptoms again resolved. CONCLUSION: In a certain subset of patients with SVS who are symptomatic from increased ICP, placement of an LPS is an effective treatment option. It appears that this subgroup of patients previously treated with ventriculoperitoneal shunting behave in a fashion similar to pseudotumor cerebri patients and respond well to lumboperitoneal shunting.     

Plain radiographic,nuclear medicine and angiographic observations of hepatogenic pulmonary angiodysplasia

Clinical and radiological findings of hepatogenic pulmonary angiodysplasia are reported in two cases. Myriad spidery pulmonary blood vessels are seen on plain radiographs and verified with right to left intrapulmonary shunting on pulmonary angiogram and pulmonary isotopic perfusion scan. Pathophysiology and differential diagnosis are discussed. We propose that the term "pulmonary angio-dysplasia" should include: 1) Pulmonary telangiectasia 2) Hereditary hemorrhagic telangiectasia (Osler-Rendu-Weber syndrome) 3) Classical discrete pulmonary arteriovenous fistula 4) Hepatogenic pulmonary angiodysplasia: pulmonary arteriovenous communications with right to left shunting secondary to hepatic cirrhosis.     

Pulmonary arterio-venous fistulae in hepatic cirrhosis.

Cyanosis, clubbing, and arterial oxygen desaturation may occur in patients with liver disease, and are attributed to the presence of pulmonary or peripheral arterio-venous shunting. Cardiac catheterisation and angiocardiography in a patient with a normal heart did not demonstrate the presence of abnormal arterio-venous anastomoses. Pulmonary shunting was proved when intravenous technetium-labelled macroaggregated albumin, normally held up in capillary networks, was passed quickly through the lungs and immediately detected in high systemic blood flow organs. The opening of peripheral and pulmonary anastomoses in patients with liver disease may be owing to the presence of a vasodilatory substance such as ferritin, which was found to be abnormally increased in the patient''s blood.     

Origin of intraventricular haemorrhage in the preterm infant.

A technique has been developed for the injection and stereomicroscopic examination of blood vessels in the preterm newborn brain. Using this technique it can be seen that in the immature brain there is a rich capillary bed in the germinal layer region supplied mainly by Heubner''s artery. Capillary channels drain directly into the terminal vein and its main branches. Study of 19 cases with spontaneous germinal layer haemorrhage (GLH) with or without intraventricular haemorrhage (IVH) failed to show rupture of the terminal vein or germinal layer infarction. In babies of up to 28 weeks'' gestation GLH developed most frequently over the body of the caudate nucleus, whereas in babies of 29 weeks'' gestation or more the haemorrhages were usually over the head of the caudate nucleus. Histological study of 10 cases of GLH failed to show rupture either of arteries or veins, though evidence of rupture at a capillary-vein junction was seen in one case and masses of fibrin adjacent to the vein wall in 2 others. Injection through the carotid artery caused prominent leaks of injection mass within the germinal layer capillary bed, often adjacent to the veins. Injection through the jugular veins in 2 cases failed to rupture the terminal vein but caused multiple vein ruptures at the junction of deep and cortical venous systems. Additional small ruptures in the germinal layer occurred in one of the cases only. It is suggested that the capillaries within the germinal layer may be ruptured by a rise in arterial pressure, particularly in conditions of hypercapnia and hypoxia.     

Recognition and early management of Reye's syndrome.

Reye''s syndrome continues to be associated with a high mortality. Out of 12 cases treated on our intensive care unit over a four year period, seven died, one suffered minimal cerebral damage, and four were normal. Rapid progression through coma stages and high peak ammonia concentrations worsened prognosis. Reye''s syndrome was suspected in only 50% of cases at the referring hospital and resulted in prompt referral to the intensive care unit in only one case. Late referral to the unit was associated with a poor outcome. Sudden neurological deterioration followed diagnostic lumbar puncture in six children. Papilloedema was an unreliable sign of raised intracranial pressure and was absent in all cases. While computed tomography of the brain was useful in providing additional evidence of raised intracranial pressure, this could only be confirmed by direct measurement. Lumbar puncture in the presence of rapidly progressive coma should be deferred until raised intracranial pressure has been excluded. To this end, early admission to a paediatric intensive care unit with facilities for computed tomography and monitoring of intracranial pressure is recommended.     

颈内静脉搭桥Rex手术治疗小儿肝外门静脉梗阻的初步探讨

目的 探讨颈内静脉搭桥Rex手术(肠系膜上静脉-门静脉左支吻合术)治疗小儿肝外门静脉梗阻的手术效果.方法 2014年10月至2015年6月共收治肝外门静脉梗阻8例,行颈内静脉搭桥Rex手术治疗,随访1～9个月,评价手术效果.手术方法:取上腹正中纵行切口,首先切断肝圆韧带,并沿其向Rex窝分离,解剖出门静脉左支矢状部3 cm;沿结肠中血管找到肠系膜上静脉,分离出3 cm;取左侧颈部横切口,切取颈内静脉7～9 cm.将颈内静脉在门静脉左支和肠系膜上静脉之间搭桥行两个端侧吻合.结果 8例中男5例,女3例,平均年龄4岁(1岁4个月至7岁),表现为消化道出血6例,脾功能亢进6例,出血合并脾亢4例.术前肝功能及凝血大致正常,胃镜检查7例食管胃底静脉曲张,1例无曲张.超声及CT均诊断门静脉海绵样变性;行经肝静脉逆行门静脉系统造影,显示门静脉左支矢状部存在7例,未显示1例(术中证实为闭锁).7例手术探查Rex窝内有血流,完成Rex手术,1例门静脉左支闭锁,改行Warren手术.吻合后经肠系膜上静脉造影显示搭桥血管通畅,肝内门静脉系统显影,肝外侧枝曲张血管明显减少或未显示.吻合后门静脉压力明显降低,吻合前PVP为(27.00±3.74)mmHg,吻合后PVP为(19.00±2.71)mmHg,吻合前后PVP压力差为(8.00±3.42)mmHg,P=0.001.术后随访,全部患儿无再次出血,6例术前脾亢患儿5例得到缓解,1例未缓解;3例于术后半年复查胃镜,食管胃底静脉曲张由重度转为轻-中度;超声检查门静脉血流均通畅,无血栓及狭窄,术后门静脉左支直径为(7.10±2.47)mm(3.3～10.5 mm).结论 Rex手术对于小儿门静脉梗阻具有良好治理效果,在降低门静脉压力的同时,恢复了肝脏血流,是EHPVO根治性手术方式,应该作为治疗小儿肝前性门静脉高压的首选手术方法.     

Intraventricular pressure dynamics in ventriculocholecystic shunting: a telemetric study

Extracranial cerebrospinal fluid shunting is the current mainstay of therapy for hydrocephalus. The generally preferred extracranial site for cerebrospinal fluid absorption is the peritoneal space; however, the cardiac atrium and the pleura are also commonly used. On occasion other CSF recipient sites, such as the gallbladder, are used secondarily when the more common absorptive spaces are unavailable or unsuitable. The gallbladder, though, exhibits its own pressure dynamics in response to physiological stimuli. The effects of gallbladder contraction on intraventricular pressure (IVP) in the presence of a ventriculocholecystic (VGB) shunt are unknown. We had the opportunity to place a VGB shunt in a 4-year-old child who was coupled to a noninvasive telemonitor. After a period of acclimation, we examined the IVP dynamics of that shunting system both pre- and postprandially. We found that before ingestion of food, the gallbladder provides a CSF recipient site similar to that of the peritoneal space. However, after ingestion of a meal containing fat, we found that IVP rose more than 10 cm water in a stereotypic fashion consistent with postprandial gallbladder contraction. The increase in IVP lasted for several hours reaching a peak at approximately 75 min postprandially. We conclude that the VGB shunt is a viable alternative for extracranial cerebrospinal fluid shunting; however, one must be aware of the peculiar dynamics of this shunt in relation to food ingestion and the potential for unusually high IVPs.     

高肺血流量对肺血管结构及内源性硫化氢影响

目的 探讨高肺血流量所致肺动脉高压(PH)大鼠肺血管结构和血浆硫化氢的变化。方法 雄性SD大鼠共16只。对分流组大鼠行腹主动脉、下腔静脉分流术;11周后以右心导管法测定肺动脉平均压(mPAP);检测右心室/体重(RV/BW)和右心室/左心室+室间隔(RV/LV+S)比值;并以光学显微镜和电子显微镜观测肺血管结构变化;以分光光度法测定血浆硫化氢含量。结果 分流组大鼠mPAP、RV/BW及RV/(LV+S)比值均明显高于对照组(P均<0.01);光镜下肺小血管肌化程度明显增强,肺中、小肌型动脉相对中膜厚度明显增加;电镜下,肺中、小肌型动脉内皮细胞增生、肥厚、肿胀,平滑肌细胞增生、肥厚,并由收缩表型向合成表型转化。分流组大鼠的血浆H_2S含量明显低于对照组,肺动脉平均压与血浆硫化氢含量呈负相关。结论 肺血管结构重建是高肺血流量所致PH重要病理基础,内源性H_2S下调可能在其形成中起重要作用。     

Experiences of postoperative chylothorax in children

Eight cases of postoperative chylothorax in children are discussed. The age of the patients varied between 5 hours and 18 months. Chylothorax was diagnosed between 3 and 14 days after operation. In 6 cases chylothorax was certainly due to damage to the thoracic duct, or other big lymph vessels in the lungs or mediastinum. These patients had no typical pulmonary changes before chylothorax developed. In 2 cases there was probably no damage to the lymph vessels, but the venous pressure in the upper part of the body was elevated by constriction of the superior caval vein. The anatomical prerequisites for chylothorax in these cases is discussed. In these patients, before chylothorax, pulmonary changes appeared in the radiograph interpreted as widened lymph vessels and caused by altered lymph flow at the periphery. If pulmonary changes of this kind appear in patients with elevation of pressure in the superior caval vein, this may be a sign that chylothorax may develop. The importance of early diagnosis is stressed. Drainage of the pleura with continuous suction has proved to be the therapy of choice. Direct operation has not been necessary in any of our cases.