Post-operative chylothorax in children: an evidence-based management algorithm

Chylothorax in infants and children

Chylothorax, the accumulation of chyle in the pleural space, is a relatively rare cause of pleural effusion in children. It can cause significant respiratory morbidity, as well as lead to malnutrition and immunodeficiency. Thus, a chylothorax requires timely diagnosis and treatment. This review will first discuss the anatomy and physiology of the lymphatic system and discuss various causes that can lead to development of a chylothorax in infants and children. Then, methods of diagnosis and treatment will be reviewed. Finally, complications of chylothorax will be reviewed.

Magnetic resonance lymphography of the thoracic duct after interstitial injection of gadofosveset trisodium: a pilot dosing study in a porcine model

BACKGROUND-RATIONALE: To investigate whether interstitial injection of gadofosveset trisodium (Ablavar®, Lantheus Medical, North Billerica, MA) would be suitable for thoracic duct (TD) imaging in a pig model.

METHODS AND RESULTS

Gadofosveset trisodium alone or premixed with 10% human serum albumin (HSA) was administered intradermally in the extremities of pigs at varying doses to visualize the TD by MRI. Two blinded readers evaluated MRIs for TD visibility. The inter-observer variability for all MR imaging sessions was assessed using the Spearman rank correlation test. MR lymphography using gadofosveset trisodium premixed with HSA yielded superior visualization of the TD compared to gadofosveset trisodium alone, with a high inter-observer agreement (correlation coefficient of 0.88 (p=0.00000115)).

CONCLUSIONS

We demonstrate that gadofosveset trisodium (premixed with 10%HSA) can be injected intradermally in order to perform MR lymphography of the thoracic duct. Since this agent is already FDA approved for MR imaging, the off-label use of it for imaging of the thoracic duct in humans is feasible, and the approach may prove to be beneficial for patients with TD abnormalities.

Utility of a clinical practice guideline in treatment of chylothorax in the postoperative congenital heart patient

BACKGROUND

Chylothorax after congenital heart surgery is a common complication with associated morbidities, but consensus treatment guidelines are lacking. Variability exists in the duration of medical treatment and timing for surgical intervention.

METHODS

After institution of a clinical practice guideline for management of postoperative chylothorax at a single center, pediatric cardiothoracic intensive care unit (ICU) in June 2010, we retrospectively analyzed 2 cohorts of patients: those with chylothorax from January 2008 to May 2010 (early cohort; n=118) and from June 2010 to August 2011 (late cohort; n=45). Data collected included demographics, cardiac surgical procedure, treatments for chylothorax, bloodstream infections, hospital mortality, length of hospitalization, duration of mechanical ventilation, and device utilization.

RESULTS

There were no demographic differences between the cohorts. No differences were found in octreotide use or surgical treatments for chylothorax. Significant differences were found in median times to chylothorax diagnosis (9 in early cohort versus 6 days in late cohort, p=0.004), ICU length of stay (18 vs 9 days, p=0.01), hospital length of stay (30 vs 23 days, p=0.005), and total durations of mechanical ventilation (11 vs 5 days, p=0.02), chest tube use (20 vs 14 days, p=0.01), central venous line use (27 vs 15 days, p=0.001), and NPO status (9.5 vs 6 days, p=0.04).

CONCLUSIONS

Institution of a clinical practice guideline for treatment of chylothorax after congenital heart surgery was associated with earlier diagnosis, reduced hospital length of stay, mechanical ventilation, and device utilization for these patients.

The impact of chylothorax on neonates with repaired congenital diaphragmatic hernia

PURPOSE

Chylothorax is a known complication in neonates after congenital diaphragmatic hernia (CDH) repair. This report uses a large international registry to evaluate risk factors, treatment, morbidity, and survival associated with chylothorax in a prospective cohort of neonates after CDH repair.

METHODS

From January 2007 to January 2010, live-born neonates with repaired, unilateral CDHs were evaluated from a prospective database for chylothorax development. Chylothorax was diagnosed based on pleural fluid examination. Study variables included patient characteristics, CDH defect and disease severity characteristics, chylothorax treatment, and survival. In addition, the temporal relationship between timing of CDH repair and extracorporeal membrane oxygenation (ECMO) therapy was evaluated as a risk factor for chylothorax. Univariate and multivariate regression analyses were utilized.

RESULTS

Among the 1383 patients evaluated, chylothorax was diagnosed in 4.6% of the cohort. Patch repair and ECMO were statistically significant risk factors for chylothorax. The odds of developing a chylothorax were significantly increased in patients with CDH repair on ECMO (aOR 2.6; 95% CI: 1.3-4.9) or after ECMO (aOR 3.1; 95% CI: 1.7-5.8). Most chylothoraces (83.1%) were successfully treated without surgery. Chylothorax patients had significant morbidity including increased oxygen use at 30days and longer length of stay. Survival was not significantly affected by chylothorax.

CONCLUSIONS

Chylothorax is a known but uncommon complication of neonatal CDH repair. In this very large series of chylothorax in association with CDH, major risk factors appear to be related to increased disease severity with the highest risk in patients repaired on or after ECMO. Chylothoraces usually improve with conservative therapy and lead to significant morbidity but not increased mortality.

Stent Implantation for Effective Treatment of Refractory Chylothorax due to Superior Vena Cava Obstruction as a Complication of Congenital Cardiac Surgery

Chylothorax is a serious complication of congenital cardiac surgery and is significantly associated with increased morbidity and mortality. Central venous obstruction, which is often related to the insertion of central venous catheters for postoperative management, is known to be an important risk factor for treatment failure and mortality associated with this condition. We present the case of a 6-month-old girl with refractory chylothorax after surgical repair of tetralogy of Fallot. The chylous drainage continued for more than 2 months despite maximal conservative therapy (water restriction, total parenteral nutrition, and infusion of somatostatin and steroid) and surgical ligation of the thoracic duct. Subsequently, we observed stenosis of the superior vena cava (SVC) caused by large thrombi possibly associated with the prolonged use of central venous catheter placed in the internal jugular vein. Because transcatheter balloon dilation failed to relieve the stenosis, we performed stent implantation for the SVC and innominate vein. After the procedure, chylous drainage dramatically reduced, and the patient was discharged from the hospital. In conclusion, central venous obstruction due to thrombosis should be routinely examined when chylothorax is diagnosed and is resistant to conservative therapy after congenital heart surgery. Stent implantation can effectively relieve the venous obstruction and thus be a life-saving treatment option for this difficult condition.

Chylothorax after surgery for congenital heart disease

PURPOSE OF REVIEW

Postoperative chylothorax is a frequently encountered pathology in the cardiac intensive care unit. The continuous loss of chyle is a challenging problem to treat and is associated with increased morbidity and mortality. The purpose of this article is to review the pathophysiology of chylothorax in patients after surgery for congenital heart disease, its implications and the current therapies available.

RECENT FINDINGS

The incidence of chylothorax has been increasing over the last two decades. Multiple uncontrolled case series describe octreotide as an effective treatment, and octreotide usage is increasing around the world for patients nonresponsive to dietary modifications. Most centers reserve surgical treatment for patients nonresponsive after 4 weeks of medical treatment. Less-invasive surgical procedures such as thoracic duct ligation by video-assisted thoracoscopy are gaining popularity.

SUMMARY

Chylothorax is commonly seen in children after surgery for congenital heart disease. The multiple and serious complications associated with chylous effusions are well known. Conservative therapy with diet modification and octreotide remain the standard initial approach. Thoracic duct ligation has been reported as a highly successful treatment but has considerable risk. Thus, this procedure should be reserved for patients nonresponsive to conservative therapy.

Fluid overload deteriorate chylothorax: evaluation in a canine model

No conservative treatments for chylothorax have yet been established, and surgical ligation of the thoracic duct is required in many cases. In the present study, we investigated the management of body fluid in a canine chylothorax model. Twelve beagle dogs were divided evenly into three groups: A, B, and C. Under general anesthesia, the thoracic duct was cut and opened, and the amount of lymph fluid leakage was measured. Intravenous extracellular fluid infusion was started at 5mL/kg/h for the first 2h, and then between 2 and 4h, the infusion rate was increased to 10 mL/kg/h in group A and to 20mL/kg/h in group B. During the first 2h after cutting the thoracic duct, the mean lymph fluid leakage rates in groups A, B, and C were 0.466, 0.635, and 0.575 mL/kg/h, respectively. The rates of leakage did not differ significantly among the groups. Between 2 and 4h, the mean rates of leakage were 0.750, 1.43, and 0.544mL/kg/h, respectively, being significantly higher in groups A and B than in group C. The amount of lymph fluid ascending the thoracic duct correlates with the amount of intravenous fluid infusion. For the management of chylothorax, it is important to avoid fluid overload.

Congenital chylothorax in a late preterm infant and successful treatment with octreotide

Chylothorax is defined as abnormal accumulation of lymphatic fluid in the pleural space and is a rare condition in neonates. Chylothorax causes respiratory and nutritional problems and a significant mortality rate. Octreotide is a long-acting somatostatin analog that can reduce lymphatic fluid production and has been used as a new strategy in the treatment of chylothorax. Here, we report a premature baby with severe bilateral pleural effusion diagnosed by prenatal ultrasound and subsequently confirmed to be congenital chylothorax after birth. This newborn baby was initially treated with bilateral chest tube insertion to relieve severe respiratory distress. However, the chylothorax recurred after a medium-chain-triglyceride-enriched formula was initiated. The accumulation of chylothorax diminished after the administration of octreotide. Therefore, octreotide may allow the patient to avoid invasive procedures, such as reinsertion of chest tubes or surgery.

Predictors of prolonged drainage of chylothorax after cardiac surgery: single centre study

INTRODUCTION AND AIM OF THE WORK: Chylothorax is a clinical challenge. This study aims at determination of the predictors of prolonged drainage of chylothorax after cardiac surgery in a single tertiary centre in Jeddah, Saudi Arabia.

PATIENTS AND METHODS

A retrospective analysis of 52 patients of chylothorax with a mean age of 30 months (range 1 month to 60 years) who developed chylothorax after heart surgery (January 2007-September 2010). Data were collected regarding patients demographics, procedures, chylous drainage and its management, complications and follow-up.

RESULTS

There was one hospital mortality. All patients were managed by fat-free diet or Monogen. Lone fat-free diet with steroids were used a in eight patients (15.4%). Somatostatin analogue (Octreotide) was used adjunctively in 7 (13.5%) patients and in two patients (3.8%), steroids and octreotide were used adjunctively. The median duration of chest tube drainage was 10.5 days (range 4-34 days). The median amount of chest tube drainage/kg/day was 18 mL (range 6.6-72 mL). All patients responded to medical treatment except one case who required thoracic duct ligation and a patient who died. The use of octreotide and steroids therapy significantly reduced the amount chest tube drainage. At median follow-up of 12 months (range 1-40 months) after hospital discharge, no recurrence of chylothorax was observed.

CONCLUSIONS

Chylothorax is much more common post-pediatric cardiac than post-adult cardiac surgery. Conservative therapy of chylothorax after cardiac surgery remains the standard approach. Steroids and or octreotide can be used with an acceptable success. The most significant predictor of prolonged chest tube drainage in chylothorax is triglyceride/cholesterol ratio more than 2.

Nutritional challenges and outcomes after surgery for congenital heart disease

PURPOSE OF REVIEW

Adequate nutrition is crucial in children after surgery for congenital heart disease. We address selected nutritional and caloric requirements for children in the perioperative period before and after cardiac surgery and explore nutritional interdependence with other system functions. Recommendations based on our current practice are made at the end of each section.

RECENT FINDINGS

Early identification of deficient oropharyngeal motor skills and vocal cord dysfunction is crucial to establish enteral nutrition safely and has been demonstrated to improve clinical outcomes. The use of prealbumin as a marker of nutritional state should be accompanied by C-reactive protein given the influence of inflammation on its levels. Insulin infusions may improve outcomes in patients with postoperative hyperglycemia. Trace element abnormalities and early identification of immune-compromised states can aid in reducing morbidity in children after cardiac surgery. Use of feeding protocols and a home surveillance system for hypoplastic left heart syndrome improves outcomes.

SUMMARY

Adequate nutritional support in children after cardiac surgery is a challenge. Attention to lesion-specific feeding problems, supplementation of trace elements and minerals, and an organized approach to pace, timing, and type of feeding are beneficial.

Chylothorax after surgery on congenital heart disease in newborns and infants -risk factors and efficacy of MCT-diet

Objectives

To analyze risk factors for chylothorax in infants after congenital heart surgery and the efficacy of median chain triglyceride diet (MCT). To develop our therapeutic pathway for the management of chylothorax.

Patients and methods

Retrospective review of the institutional surgical database and patient charts including detailed perioperative informations between 1/2000 and 10/2006. Data analyzing with an elimination regression analysis.

Results

Twenty six out of 282 patients had chylothorax (=9.2%). Secondary chest closure, low body weight, small size, longer cardiopulmonary bypass (242 ± 30 versus 129 ± 5 min) and x-clamp times (111 ± 15 versus 62 ± 3 min) were significantly associated with chylothorax (p < 0.05). One patient was cured with total parenteral nutrition (TPN) and one without any treatment. 24 patients received MCT-diet alone, which was successful in 17 patients within 10 days. After conversion to regular alimentation within one week only one chylothorax relapsed. Out of 7 patients primarily not responsive to MCT-diet, 2 were successfully treated by lysis of a caval vein thrombosis, 2 by TPN + pleurodesis + supradiaphragmatic thoracic duct ligation, one by octreotide treatment, and two patients finally died.

Conclusions

Chylothorax may appear due to injury of the thoracic duct, due to venous or lymphatic congestion, central vein thrombosis, or diffuse injury of mediastinal lymphatic tissue in association with secondary chest closure. Application of MCT alone was effective in 71%, and more invasive treatments like TPN should not be used in primary routine. After resolution of chylothorax, MCT-diet can be converted to regular milk formula within one week and with very low risk of relapse.

Chylothorax: diagnostic approach

PURPOSE OF REVIEW

This review evaluates recent research findings and proposes an up-to-date diagnostic approach for patients with suspected chylothorax.

RECENT FINDINGS

Typically, chylothorax is a milky exudate with high triglyceride content (>110 mg/dl). However, milky appearance is not always the case and triglyceride levels can be less than 110 mg/dl, especially in fasting or malnourished patients. Transudative chylothoraces have been reported when cirrhosis, nephrosis or heart failure co-exist. In addition, although the vast majority of the white blood cells in chyle are lymphocytes, chylothoraces can be neutrophilic, especially the postsurgical ones.

SUMMARY

Chylothorax is the accumulation of chyle into the pleural cavity usually due to thoracic duct leak and should be suspected not only in patients with milky effusions but also in the presence of certain co-morbidities or history of chest/neck trauma. Fluid triglycerides more than 110 mg/dl or less than 50 mg/dl virtually establish or exclude the diagnosis, respectively; ambiguous cases with values 50-110 mg/dl require lipoprotein analysis for the demonstration of chylomicrons. In fasting or malnourished patients lipoprotein analysis is suggested even with triglycerides less than 50 mg/dl. Typical pleural fluid in chylothorax is a lymphocytic exudate with low lactate dehydrogenase; atypical fluid characteristics (i.e. transudative nature, neutrophil-predominance or high lactate dehydrogenase) may be a sign of additional causes of pleural fluid accumulation.

Medical and surgical management of chylothorax and associated outcomes

Chylothorax is an uncommon form of pleural effusion that can be associated with traumatic and nontraumatic causes. Optimal management and outcome for patients with chylothorax remain unclear. This retrospective single-center study assessed the modes of management for chylothorax in 74 adult patients (> or =18 years old) and associated outcomes. The role of lymphangiographic imaging was also evaluated. Initial treatment approach was nonsurgical in 57 patients (77%) but a surgical procedure (pleurodesis, thoracic duct ligation, and/or surgical repair) was eventually performed in 44 patients (59%). The rate of resolution with initial treatment measures was significantly worse for patients with nontraumatic chylothorax compared with those with traumatic causes (27% versus 50%, P = 0.048). Even after additional therapeutic maneuvers including surgery, chylous effusion recurred more commonly in nontraumatic chylothorax when compared with the traumatic group (50% versus 13%, respectively, P < 0.001). Lymphatic imaging did not seem to materially influence management. Nonsurgical approaches may lead to resolution of the chylothorax in nearly one half of patients with traumatic chylothorax but in only a minority of those with nontraumatic chylothorax. The majority of patients with nontraumatic chylothorax will eventually require surgical maneuvers, but one third of such patients still fail to resolve their chylothorax.

Chylothorax: diagnosis and management in children

Chylothorax is the accumulation of chyle in the pleural space, as a result of damage to the thoracic duct. Chyle is milky fluid enriched with fat secreted from the intestinal cells and lymphatic fluid. Chylothorax in children, is most commonly seen as a complication of cardiothoracic surgery but may occur in newborns or conditions associated with abnormal lymphatics. The diagnosis is based on biochemical analysis of the pleural fluid, which contains chylomicrons, high levels of triglycerides and lymphocytes. Investigations to outline the lymphatic channels can prove helpful in some cases. Initial treatment consists of drainage, dietary modifications, total parenteral nutrition and time for the thoracic duct to heal. Somatostatin and its analogue octreotide may be useful in some cases. Surgery should be considered for patients who fail these initial steps, or in whom complications such as electrolyte and fluid imbalance, malnutrition or immunodeficiency persist. Surgical intervention may be attempted thoracoscopically with repair or ligation of the thoracic duct.