CASE STUDY:

Post-operative Chylothorax in Infant

Jamie Rasmussen

Dietetic Intern, 2009-2010

University of Maryland Medical Center

PATIENT OVERVIEW

The pt is a 6 week-old male infant with a PMH significant for 37-week gestation twin birth at UMMS with Tetralogy of Fallot and development of mild-RDS. Pt stayed in NICU at UMMS for 12 days prior to transferring to Mt. Washington to advance oral feedings to meet needs. Pt returned to UMMS 5/21 for TOF repair.

DISEASE OVERVIEW1

Tetralogy of Fallot (TOF): congenital heart abnormalities that lead to inadequate oxygenation of the blood resulting in cyanosis and shortness of breath. The four defining factors are shown below.

PERTINENT INPATIENT TIMELINE 5/21 Admission 5/21 Right ventricular outflow tract (RVOT)

augmentation with excision of pulmonary valve (pt was scheduled for full TOF repair, however, pt desatted during the procedure and required chest compressions to maintain perfusion, the pt then underwent cardiopulmonary bypass with a modified procedure without further incident)

5/21 Placement of central line during RVOT procedure

5/25 Full TOF repair with chest left open 5/30 Right-sided pigtail catheter placed to drain

pleural effusion, fluid milky in appearance, sent for evaluation, diagnosed as chylothorax

PERTINENT INPATIENT TIMELINE (CONT.) 6/2 Chest closed 6/6 Extubated 6/7 TPN dc’d with EN advancement on Enfaport 6/8 TPN restarted with chyle leak output

increase, EN dc’d 6/10 R pigtail removed 6/11 R pigtail replaced with chyle

reaccumulation 6/15 or 6/16 Planned return to OR for thoracic

duct ligation

OVERALL GI STATUS

GI system remained functional, however, use of the gut for feeds was complicated by low perfusion with pressor support, procedures with NPO status and chyle leak refractory to conservative nutrition therapy with high MCT-oil formula.

CHYLOTHORAX OVERVIEW2

INITIAL PATIENT ASSESSMENT-5/24S: Pt intubated on oscillator

O: 5 week old, POD#4 RVOT, awaiting full TOF repair.

Wt: 3.18 kg(3-10%), Ht: 50.5 cm (3-10%), Wt/Ht: 25-50%, IBW: 3.4 kg (94% IBW)

Diet: NPOEst. Needs: 90-100kcal/kg & 2.2g/kg proteinMeds of note: zantac, PRN: lyte replacement

protocol, gtt: dopamine, fentanyl, lasix, heparin, nitroprusside, IVF: 1/2NS@1.5ml/hr

Labs of note: hypokalemia, lactate trending down

LACTATE TREND

5/21 RVOT Augmentation Pt NPO

5/25 Full TOF repair Feeds Initiated

INITIAL PATIENT ASSESSMENT (CONT.)

A: Pt intubated on oscillator, to return to OR for VSD closure. Recommend NJ feeds after OR until extubated then recommend PO feed transition. Noted hypokalemia with PRN KCl, pt on lasix. Pt @ high nutrition risk.

PES: Inadequate protein-energy intake related to NPO status as evidenced by NPO x4 days with pt not indicated for EN 2/2 questionable gut perfusion and not indicated for PN 2/2 fluid restriction.

INITIAL PATIENT ASSESSMENT (CONT.)

P: 1-Recommend place and verify NJ tube once cleared for enteral feeds. Initiate Similac 20kcal/oz @ 4 ml/hr, advance 4 ml/hr q 8 hours to goal 16 ml/hr. Once at fluid goal, recommend change to Similac 24kcal/oz. Provides 97kcal/kg & 2 g/kg protein.

OUTCOME: Similac 20kcal/oz started at 4 ml/hr via NJ on 5/25

FOLLOW-UP NOTE-5/27

I: Pt remains intubated, POD#3 full TOF repair, chest remains openLabs of note: hypokalemiaMeds of note: zantac, gtt: lasix, dopamine, PRN: KClNutrition Related Issues: Per rounds, plan to advance feeds to goal, 5/26 abdXR-NJ in duodenumCurrent Nutrition Therapy: Sim 20kcal/oz @ 4 ml/hr (21 kcal/kg & 0.6 g/kg protein)

E: Pt tolerating trophic enteral feeds, team plans to advance to goal. Noted hypokalemia, pt on lasix 2/2 fluid overload with PRN KCl, will monitor. Pt remains @ high nutrition risk.

FOLLOW-UP NOTE-5/27 (CONT.)

PES: Altered nutrition-related lab value related to lasix provision for diuresis in setting of fluid overload as evidenced by hypokalemia with PRN potassium.

R: 1-Advance enteral feeds.

OUTCOME: Similac 20 kcal/oz formula advanced to 16 ml/hr (goal rate) but reduced back to 4 ml/hr (@ 2 ml/hr 5/27) 2/2 fluid overload.

FOLLOW-UP NOTE-6/1

S: Pt intubatedO: Chest remains open s/p full TOF repair, ¾

maintenance fluid restriction 2/2 fluid overload, 5/31 chest washout, NJ feeds stopped 5/30 2/2 chylothorax diagnosis

Diet: NPOTPN: providing 62 kcal/kg & 2 g/kg proteinEst. Needs: 90-100 kcal/kg & 2.2 g/kg proteinMeds of note: albumin, zantac, PRN: KCl, gtt:

dopamine, milrinone, lasix, epinephrineLabs of note: hypokalemia, pleural fluid test

5/30 PLEURAL FLUID RESULTS

0516: milky appearanceWBC 98/mcL, RBC 10,300/mcL and TG 763 mg/dl, fluid chol 37 mg/dl, mostly neutrophils

and lymphocytes

1327: milky appearanceWBC 6650/mcL, RBC 16,250/mcL and TG 828, leukocytes almost

entirely lymphocytes

FOLLOW-UP NOTE-6/1 (CONT.)

A: Pt with fluid limit restricting ability to replace lytes in TPN, recommend continuing PRN lyte replacement. Pt with active chyle leak, per team plan to maintain NPO status with TPN.

PES: Altered GI function related to alteration in GI structure as evidenced by chylothorax s/p TOF repair with chyle output increase with EN advancement.

P: 1-Continue TPN for nutrition support with lyte repletions through PRN runs. 2-Consider adding trophic enteral feeds. Recommend Enfaport @ 4 ml/hr via NJ.

OUTCOME: TPN continues with 75% fluid limit

TPN PROVISION WITH FLUID LIMIT-6/3PT ON .75X MAINTENANCE FLUID LIMIT

Components Notes:

D: 21% GIR: 6.3

AA: 4.3% Provides: 1/7g/kg/day

Lytes: K+ 3.5 mEq/kg/day (TPN only)

3.5mEq/kg/day total

Na 2.8 mEq/kg/day (TPN)1.2 mEq/kg/day (IV drips)

4mEq/kg/day total

Overall provision: 60 kcal/kg (60% estimated needs)

Enfaport Infant Formula3

•30 kcal/oz formula (1 kcal/ml), to get 20 kcal/oz mix 12 fl oz of formula with 6 fl oz water

•83% of fat from MCT oil, other fat sources: soybean oil, DHA and ARA

•Specially designed for chylothorax and LCHAD patients

MCT VS. LCT OILS4

FOLLOW-UP NOTE-6/4

I: Currently intubated, possible extubation 6/5, chylothorax hemothorax with possible chyle leak still persistingLabs of note: hypokalemia, TG 103 6/2Meds of note: albumin, lasix, zantac PRN: lyte replacement protocol, gtt: dopamine, heparin, milrinoneCurrent nutrition therapy: TPN 60 kcal/kg & 1.7 g/kg protein

FOLLOW-UP 6/4

E: Per team plan to continue TPN with possible transition to EN once extubated, recommend Enfaport to reduce exacerbation of chyle output. Pt remains @ high nutrition risk.

PES: Inadequate intake from parenteral nutrition related to fluid limit as evidenced by provision of parental nutrition providing approximately 60% of needs with fluid remaining after IV fluid volume deducted.

FOLLOW-UP NOTE-6/4 (CONT.)

R: 1-Continue TPN for nutrition support2- Once patient considered for enteral feeds,

recommend Enfaport 20kcal/oz @ 2-3 ml/hr for trophic feeds with TPN or Enfaport 20kcal/oz @ 4 ml/hr advancing 4 ml/hr q 8 hours to goal 20 ml/hr with EN as sole nutrition support. EN rec provides 105 kcal/kg & 0.7 g/kg protein.

OUTCOME: TPN continued 2 more days, 6/6-Pedialyte 30 ml q 3 hours initiated-90 ml total, Enfaport 20 kcal/oz initiated 60 ml q 3 hours, PO first gavage remainder. 6/8-Enfaport dc’d with chyle output increase. TPN restarted.

FOLLOW-UP NOTE 6/9

S: TPN dc’d 6/7 with EN advancement, TPN restarted 6/8

O: Chylothorax output increased with advancement of EN with EnfaportDiet: NPOTPN: providing 108 kcal/kg & 2 g/kg proteinEst. Needs: 110-140 kcal/kg & 3 g/kg proteinMeds of note: lasix, prevacidLabs of note: hyperglycemia, hypophosphatemiaRight pigtail output (chyle): 70 ml (6/8), 110 ml (6/7)Wt: 3.06 kg

Weight Pattern

4/15 Birth:2.32 kg4/27: 2.44kg5/18 3.06 kg5/21 3.06 kg 6/6: 3.055 kg6/7: 3.1 kg6/9: 3.06 kg 6/10: 2.94 kg6/11: 3.05 kg6/12: 3.07 kg6/13: 3.02 kg

Pt wt not routinely

measured as inpatient post-operatively.

Expected growth velocity at this

age: 25-35 grams/day

If pt had grown at expected rate, wt should have been

in the range of 3.6-3.8kg by

6/13.

3rd percentile

FOLLOW-UP NOTE 6/9 (CONT.)

A: Per rounds discussion, pt to continue on TPN with increased chyle output. Noted hyperglycemia with high GIR, noted hypophosphatemia – will adjust TPN accordingly. Pt remains @ high nutrition risk.

PES: Malnutrition related to lack of wt gain throughout hospitalization as evidenced by wt for length <3%, loss of 150g body weight and inadequate gain. Pt with expected gain of 25-35g/day for a total of 475-665 g total wt gain by 6/9.

FOLLOW-UP NOTE 6/9 (CONT.)

P: 1-Recommend continuing TPN 2 weeks while maintaining NPO. Adjust daily TPN: GIR to 14.2, phos to 0.7 mmol/kg, AA to 3.5g/kg, IL to 3.5 g/kg. Provides 118 kcal/kg.

2-Check wt q day3-Consider somatostatin/octreotide as adjuvant

therapy for chylothorax

OUTCOME: Pt continued on TPN, planned for thoracic duct ligation 6/14 or 6/15, octreotide not used for adjuvant therapy

TPN PROVISION WITHOUT FLUID LIMIT-6/10PT ON 1.2X MAINTENANCE FLUID LIMITComponents Notes:

D: 20% GIR: 14.2

AA: 3.4% Provides: 3.5g/kg/day

Lytes: K+ 2.5 mEq/kg/day (TPN only)

2.5mEq/kg/day total

Na 5 mEq/kg/day (TPN only)

5mEq/kg/day total

Overall provision: 118 kcal/kg (100% estimated needs)

Thoracic Duct Ligation Procedure Overview

For this pt, plan is to reintubate and enter chest through R thoracotomy incision. The leak will then be identified and sutured. Once pt is out of OR plan to extubate soon thereafter, CT removed around 24 hours post-op. Feeding plan is to start enteral or PO feeds within 24-48 hours with standard formula and advance to full goal within 24-48 hours after that time.

Image from Cardiothoracic Surgery Network5

EXPECTED OUTCOME:

Pt expected to tolerate standard formula feeds after thoracic duct ligation procedure.

Plan to discharge home if pt is able to tolerate full PO feeds.

Plan to discharge back to Mt. Washington if pt requiring PO plus gavage feeds to meet needs.

Long-term prognosis is good with anticipated future complications from chylothorax or TOF.

REVIEW OF LITERATURE #1

Owens J, Musa N. Nutrition Support After Neonatal Cardiac Surgery. Nutrition in Clinical Practice. 2009;24:242-249.

The main purpose of this review article is to present information concerning the nutrition and metabolic aspects of clinical care in pediatric cardiac surgery involving cardiopulmonary bypass.

44 references; 1981-2008 (most references are from early- to mid-2000s)

Main topics from the article include: CHD and metabolic stress response overview, post-operative metabolic consequences, barriers to nutrition provision, nutrition support after cardiac surgery, neonatal energy expenditure and complications with nutrition implications.

REVIEW OF LITERATURE #1 (Cont.)

Relation to case: The patient underwent surgery for a form of CHD which required CPB. Stress response to surgical procedure considered when reviewing labs. Encountered many barriers to meeting pts nutrient needs 2/2 hypotension, fluid limits, mechanical ventilation, and electrolyte abnormalities. Patient then developed a post-surgical chylothorax leading to further complications with meeting nutrition needs.

REVIEW OF LITERATURE #1 (Cont.)

Applications of research:Article recommended indirect calorimetry for estimation of nutrient needs, but that is not an option at our facility. Estimated needs based on RDA for age with some adjustment for mechanical ventilation and fluid limit. Nutrition support options adjusted for pt status based on fluid limit and chyle leak.

UMMC practice matches research recommendations.

REVIEW OF LITERATURE #2Panthongviriyakul C, Bines J. Post-operative chylothorax in children: An evidence-based management algorithm. Journal of Paediatrics and Child Health. 2008;44:716-721.

The main purpose of this review article was to develop an

evidence-based algorithm for management of post-operative chylothorax in children taking into consideration nutrition support options and adjuvant therapies.

76 references: 1964-2007 (majority of references from 1990s-2007)

Main topics from the article include: nutrition support centered on high-MCT diets or TPN to reduce activation of thoracic lymph flow from a presence of high-LCT fats; medications such as somatostatin/octreotide to decrease gastric, pancreatic and intestinal secretions, and surgical intervention for leaks that don’t resolve within four weeks.

Fig. 2 Therapeutic algorithm for management of post-operative chylothorax.

REVIEW OF LITERATURE #2 (Cont.)

Relation to case: Pt developed a post-operative chylothorax

Research Applications: Pt EN changed from Similac 20 to Enfaport 20 when chylothorax diagnosed. Chylothorax output did not improve so nutrition support changed to TPN. Chyle leak improved so team changed pt back to Enfaport, but leak increased and the decision was made to continue TPN for 2-3 weeks based on article algorithm timeline. As discussed at rounds, team considering somatostatin for adjuvant therapy if necessary.

REVIEW OF LITERATURE #2 (Cont.)

UMMC practice matches the article recommendations. There was some confusion about the timeline for maintaining NPO with the increase in chyle output, but the PICU and cardiac teams both agreed to timeline for TPN based on nutrition recommendations from article. The team chose to remove the pigtail catheter that was draining the chyle, but presence of output, although not amount, can still be monitored through chest x-ray images.

REVIEW OF LITERATURE #3

Milonakis M, Chatzis A, Giannopoulos N, et al. Etiology and Management of Chylothorax Following Pediatric Heart Surgery. Journal of Cardiac Surgery. 2009;24:369-373.

The purpose of this article was to identify the management of chylothorax within the patient population at Onassis Cardiac Surgery Center in Athens, Greece.

Retrospective review of 1,341 pediatric heart surgery patients from September 1997-August 2006 at Onassis Cardiac Surgery Center in Athens, Greece. Of the 1,341, 18 patients developed chylothoraces.

REVIEW OF LITERATURE #3 (Cont.)

Results: Therapeutic protocol at this facility resulted in

no deaths among the studied patients. Of the 18 patients, 15 (83%) responded to

conservative therapy involving draining of the chyle collection, TPN or EN with low-fat formula and, occasionally, somatostatin. Chyle leaks persisted for a median of 16 days for these patients.

The median for the three patients (17%) who did not respond as well to conservative treatment was 24 days. These three patients had to undergo surgical intervention to resolve their chylothoraces.

REVIEW OF LITERATURE #3 (Cont.)

Relation to case: Pt developed a post-operative chylothorax

Research Applications: Pt managed conservatively with appropriate nutrition support and a pigtail catheter for drainage of chyle fluid. Consideration given to somatostatin as a drug therapy options.

UMMC practice matches article recommendations for chylothorax management.

CONCLUSIONS: Infants at greater risk for malnutrition 2/2 low energy

stores and a greater rate of protein breakdown Indirect calorimetry is preferred method of calorie

need estimation. Predictive equations may not accurately reflect nutrition needs.

Enteral feeds with low-fat, high-MCT formulas appropriate with chylothoraces

TPN should be considered if chyle leak does not improve with EN

Adjuvant therapies such as somatostatin may be used, but haven’t been shown to be widely beneficial

Thoracic duct ligation is considered for treatment when chyle leak does not resolve with conservative methods

REFERENCES1- National Institutes of Health and U.S. National Library of Medicine. Medline Plus,

Encyclopedia: Tetralogy of Fallot. Available at: http://www.nlm.nih.gov/medlineplus/ency/imagepages/18088.htm. Accessed June 1, 2010.

2- Panthongviriyakul C, Bines J. Post-operative chylothorax in children: An evidence-based management algorithm. Journal of Paediatrics and Child Health. 2008;44:716-721.

3- Mead Johnson, Healthcare Resource Professional Center, Medical Formulas, Enfaport. Available at: http://www.enfamil.com/app/iwp/hcp2/content2.do?dm=enf&id=/HCP_Home2/ProductInformation/hcpProducts/hcpMedical/hcpEnfaport&iwpst=B2C&ls=0&csred=1&r=3453646560/. Accessed June 10, 2010.

4- Milonakis M, Chatzis A, Giannopoulos N, et al. Etiology and Management of Chylothorax Following Pediatric Heart Surgery. Journal of Cardiac Surgery. 2009;24:369-373.

5- Cardiothoracic Surgery Network. Ligation of the Thoracic Duct for Chylothorax. Available at: http://www.ctsnet.org/sections/clinicalresources/thoracic/expert_tech-19.html. Accessed June 14, 2010.

6- Owens J, Musa N. Nutrition Support After Neonatal Cardiac Surgery. Nutrition in Clinical Practice. 2009;24:242-249.

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Questions

SPECIAL THANKS TO: Faith Hicks and Sara Wittenberg for their

endless education during the 3-week pediatric rotation and 4 weeks of staff relief and also to Laura Wohlberg and Shanti Lewis during the 1-week NICU rotation.

The entire clinical nutrition staff at UMMS for this year of excellent clinical training!

Caitlin, Elaine and Amanda for adding to the enjoyment of this year.

The other 4 case study patients I had selected throughout the year…