Changing the paradigm: omegaven for the treatment of liver failure in pediatric short bowel syndrome

Pediatric intestinal failure-associated liver disease is reversed with 6 months of intravenous fish oil

BACKGROUND

Studies have suggested that when intravenous (IV) soybean oil (SO) is replaced with fish oil (FO), direct hyperbilirubinemia is more likely to resolve. The necessary duration of FO has not been established. This study seeks to determine if 24 weeks of FO is an effective and safe therapy for intestinal failure-associated liver disease (IFALD).

MATERIALS AND METHODS

This is a clinical trial using patients with IFALD between the ages of 2 weeks and 18 years. SO was replaced with FO (1 g/kg/d) in 10 patients who were receiving most of their calories from parenteral nutrition (PN). Patients were compared with 20 historic controls receiving SO. SO for both groups was prescribed by the primary medical team at variable doses. The primary outcome was time to reversal of cholestasis. Secondary outcomes were death, transplant, and full enteral feeds. Safety measurements included growth, essential fatty acid deficiency, and laboratory markers to assess bleeding risk.

RESULTS

The Kaplan-Meier method estimated that 75% in the FO group would experience resolution of cholestasis by 17 weeks vs 6% in the SO group (P < .0001). When compared with the SO group, the FO group had decreased serum direct bilirubin concentrations at weeks 8 (P = .03) and 12, 16, 20, and 24 weeks (P < .0001). Although length z score at the end of the study increased in the FO group compared with baseline (P = .03), there were no significant differences in other outcomes.

CONCLUSIONS

A limited duration of FO appears to be safe and effective in reversing IFALD.

Incidence, prevention, and treatment of parenteral nutrition-associated cholestasis and intestinal failure-associated liver disease in infants and children: a systematic review

BACKGROUND

Cholestasis is a significant life-threatening complication in children on parenteral nutrition (PN). Strategies to prevent/treat PN-associated cholestasis (PNAC) and intestinal failure-associated liver disease (IFALD) have reached moderate success with little supporting evidence. Aims of this systematic review were (1) to determine the incidence of PNAC/IFALD in children receiving PN for ≥ 14 days and (2) to review the efficacy of measures to prevent/treat PNAC/IFALD.

METHODS

Of 4696 abstracts screened, 406 relevant articles were reviewed, and studies on children with PN ≥ 14 days and cholestasis (conjugated bilirubin ≥ 2 mg/dL) were included. Analyzed parameters were (1) PNAC/IFALD incidence by decade and by PN length and (2) PNAC/IFALD prevention and treatment (prospective studies).

RESULTS

Twenty-three articles (3280 patients) showed an incidence of 28.2% and 49.8% of PNAC and IFALD, respectively, with no evident alteration over the last decades. The incidence of PNAC was directly proportional to the length of PN (from 15.7% for PN ≤ 1 month up to 60.9% for PN ≥ 2 months; P < .0001). Ten studies on PNAC met inclusion criteria. High or intermediate-dose of oral erythromycin and aminoacid-free PN with enteral whey protein gained significant benefits in preterm neonates (P < .05, P = .003, and P < .001, respectively). None of the studies reviewed met inclusion criteria for treatment.

CONCLUSIONS

The incidence of PNAC/IFALD in children has no obvious decrease over time. PNAC is directly correlated to the length of PN. Erythromycin and aminoacid-free PN with enteral whey protein have shown to prevent PNAC in preterm neonates. There is a lack of high-quality prospective studies, especially on IFALD.

The impact of multi-disciplinary intestinal rehabilitation programs on the outcome of pediatric patients with intestinal failure: a systematic review and meta-analysis

BACKGROUND

Pediatric intestinal failure (IF) is a complex clinical problem requiring coordinated multi-disciplinary care. Our objective was to review the evidence for the benefit of intestinal rehabilitation programs (IRP) in pediatric IF patients.

METHODS

A systematic review was performed on Medline (1950-2012), Pubmed (1966-2012), and Embase (1980-2012) conference proceedings and trial registries. The terms short bowel syndrome, intestinal rehabilitation, intestinal failure, patient care teams, and multi-disciplinary teams were used. Fifteen independent studies were included. Three studies that were cohort studies, including a comparison group, were included in a meta-analysis.

RESULTS

Compared to historical controls (n=103), implementation of an IRP (n=130) resulted in a reduction in septic episodes (0.3 vs. 0.5 event/month; p=0.01) and an increase in overall patient survival (22% to 42%). Non-significant improvements were seen in weaning from PN (RR=1.05, 0.88-1.25, p=0.62), incidence of IFALD (RR=0.2, 0-17.25, p=0.48), and relative risk of liver transplantation (3.99, 0.75-21.3, p=0.11). Other outcomes reported included a reduction in calories from parenteral nutrition (100% to 32%-56%), earlier surgical/transplant evaluation, and improved coordination of patient care.

CONCLUSION

For pediatric IF patients, IRPs are associated with reduced morbidity and mortality. Standardized clinical practice guidelines are necessary to provide uniform patient care and outcome assessment.

Four-week parenteral nutrition using a third generation lipid emulsion (SMOFlipid)--a double-blind, randomised, multicentre study in adults

PRECIS

The aim of this study was to evaluate the safety and tolerance of a soybean/MCT/olive/fish oil emulsion in intestinal failure patients on long-term parenteral nutrition. 73 patients took part in a randomized, double-blind, multi-centre study. The study demonstrates that the lipid emulsion containing four different types of oils is safe and well tolerated in long-term PN.

BACKGROUND & AIM

Long-term safety and efficacy of a lipid emulsion containing soybean oil, medium-chain triglycerides (MCT), olive oil and fish oil and enriched in vitamin E have not yet been evaluated in adult patients requiring long-term parenteral nutrition (PN).

METHODS

Randomised, controlled, double-blind, multicentre study in 73 patients with stable intestinal failure, requiring PN with either soybean/MCT/olive/fish emulsion (SMOFlipid, n = 34) or soybean emulsion (Intralipid, control n = 39) for 4 weeks. Safety and tolerance were monitored with standard clinical laboratory parameters, adverse events (AEs, according to the Common Terminology Criteria for Adverse Events (CTCAE) classification v 3.0) and vital signs. Fatty acid pattern in red blood cell phospholipids and plasma lipoproteins, serum Vitamin E, Interleukin (IL)-6, and soluble tumour necrosis (s-TNF)-receptor(R)II were also evaluated.

RESULTS

Mean concentrations of alanine transaminase (ALT), aspartate transaminase (AST) and total bilirubin, whilst remaining within the reference range, were significantly lower with soybean/MCT/olive/fish (SMOF) oil emulsion after the treatment period compared to control. Eicosapentaenoic acid, docosahexaenoic acid and n-3/n-6 fatty acid ratio increased in the SMOF group, while they remained unchanged in the control in plasma and RBC. Serum α-tocopherol concentrations significantly increased in the study group compared to control (p = 0.0004). IL-6 and sTNF-RII levels did not change during the study period. Grade 4 (serious) adverse events occurred in 2 SMOF patients and in 8 control patients (p = 0.03).

CONCLUSIONS

Soybean/MCT/olive/fish emulsion was safe and well tolerated over 4 weeks and leads to positive change in fatty acids profile.

High rates of resolution of cholestasis in parenteral nutrition-associated liver disease with fish oil-based lipid emulsion monotherapy

OBJECTIVE

To determine factors leading to resolution of cholestasis in patients with parenteral nutrition-associated liver disease treated with fish oil-based lipid emulsion (FOLE).

STUDY DESIGN

Prospective observational study of 57 infants <6 months of age with parenteral nutrition-associated liver disease who received parenteral FOLE as monotherapy.

RESULTS

Median gestational age of subjects at birth was 28 weeks (range 22.7-39.5). Median conjugated bilirubin level at initiation of therapy with FOLE was 7.5 mg/dL (range 2.1-25). Resolution of hyperbilirubinemia (conjugated bilirubin <2.0 mg/dL) and survival to hospital discharge occurred in 47 (82.5%) infants. Median number of days to resolution of cholestasis was 35 (range 7-129). Ten infants (17.5%) died. Non-survivors showed a trend towards being more premature than survivors at birth (25.9 vs 29.1 weeks, P = .056). Infants with higher conjugated bilirubin at initiation of therapy (>10.0 compared with <5.0 mg/dL) had longer times to resolution (98 vs 56 days, P < .005). Time to resolution correlated inversely with gestational age at birth (r(2) = 0.14, P = .02) and directly with time to receive 100% calories enterally (r(2) = 0.12, P = .03).

CONCLUSIONS

Younger gestational age infants demonstrated higher degree of cholestasis, longer time to resolution of cholestasis, and increased mortality. Higher levels of cholestasis were associated with longer time to resolution. FOLE monotherapy led to resolution of cholestasis in all surviving infants.

Intestinal lengthening and nutritional outcomes in children with short bowel syndrome

BACKGROUND

Intestinal lengthening remains a treatment option in pediatric short bowel syndrome. However, clinical indications and nutritional outcomes from bowel lengthening are not well defined.

METHODS

A retrospective review of a prospective database was conducted of patients who underwent bowel lengthening using serial transverse enteroplasty (STEP) at a single center.

RESULTS

Sixteen children who underwent 19 STEP procedures were identified. STEP increased median small bowel length from 84 cm (range, 19 to 295 cm) to 103 cm (range, 24 to 375 cm) (P = .0001). Caloric provisions from parenteral nutrition were decreased after STEP (69% vs 0%, P < .01). Of 15 subjects in the nutritional analysis, 12 (80%) had improved enteral tolerance, and 9 (60%) achieved enteral autonomy after STEP. Six STEP procedures were not associated with improvements in enteral nutrition, and 5 (83%) were performed in children with gastroschisis.

CONCLUSIONS

A majority of children with short bowel syndrome were weaned off parenteral nutrition after STEP. Gastroschisis may portend a less optimal outcome from the procedure.

Short bowel syndrome in the NICU

Short bowel syndrome (SBS) is the most common cause of intestinal failure in infants. In neonates and young infants, necrotizing enterocolitis, gastroschisis, intestinal atresia, and intestinal malrotation/volvulus are the leading causes of SBS. Following an acute postsurgical phase, the residual gastrointestinal tract adapts with reorganization of the crypt-villus histoarchitecture and functional changes in nutrient absorption and motility. A cohesive, multidisciplinary approach can allow most neonates with SBS to transition to full enteral feeds and achieve normal growth and development. In this article, the clinical features, management, complications, and prognostic factors in SBS are reviewed.

Intestinal transplantation in infants with intestinal failure

Intestinal failure (IF) occurs when a person's functional intestinal mass is insufficient. Patients with IF are placed on parenteral nutrition (PN) while efforts are made to restore intestinal function through surgical or medical intervention. Patients who fail standard IF therapies may be candidates for intestinal transplantation (IT). Clinical outcomes for IT have improved to make this therapy the standard of care for patients who develop complications of PN. The timing of referral for IT is critical because accumulated complications of PN can render the patient ineligible for IT or can force the patient to await multiorgan transplantation.

The effect of lipid restriction on the prevention of parenteral nutrition-associated cholestasis in surgical infants

PURPOSE

Surgical infants requiring long-term parenteral nutrition (PN) are at risk for parenteral nutrition-associated liver disease (PNALD). The purpose of this study was to determine the effect of a lipid restricted PN regimen in preventing the development of PNALD in surgical infants.

METHODS

In 2009, we implemented a lipid restricted strategy in surgical infants expected to be on long-term PN using a soy-based lipid emulsion at a goal provision of 1g/kg/day throughout a patient's entire PN course. An experimental cohort of surgical infants treated with lipid restriction from 2009 to 2011 (n=82) was retrospectively compared to a control cohort of infants from 2005 to 2008 receiving standard intravenous lipid dosing (n=132). A multivariable relative risk regression model was constructed analyzing the association between lipid restriction and PNALD.

RESULTS

Patients admitted during the lipid restriction era had reduced daily lipid provisions compared to the control group (p<0.001). There were no significant differences in demographic or measured clinical characteristics between the two groups. A significant reduction in the incidence of PNALD was demonstrated in the lipid restricted group compared to the control group (22% vs. 43%, p=0.002). On multivariable relative risk regression, patients treated with standard lipid provisions were 1.77 times more likely to develop PNALD than patients who were lipid restricted (95% CI: 1.2-2.7; p=0.007).

CONCLUSION

Restriction of intravenous soy-based lipid in PN-fed surgical infants is associated with a reduction in the incidence of liver disease. Early lipid restriction should be considered in all surgical infants who require PN as a preventative measure against PNALD.

Ultrashort bowel syndrome in children

OBJECTIVE

Recent data have demonstrated improved survival in children with intestinal failure. We hypothesized that this trend would also be observed in children with ultrashort bowel syndrome.

METHODS

A prospective database from Seattle Children's Intestinal Failure Program was used to evaluate outcomes and morbidities of consecutive patients with 10 cm or less of small bowel enrolled in the program since 2005. Data are listed as median (range).

RESULTS

Five patients were identified with a bowel length of 6 (1-10) cm and follow-up of 54 (43-61) months. All children have survived and are currently between 3.5 and 5.5 years of age. One patient underwent isolated intestinal transplantation and one patient is currently listed for intestinal transplantation. The transplanted child is fully enterally fed. The other patients remain at least partially dependent on parenteral nutrition. None of these patients have current evidence of parenteral nutrition-associated liver disease. Patients have required extensive care after referral to our program, including 18 (15-32) visits to the emergency room, 152 (114-273) days of inpatient care, and 6 (5-9) central line-associated blood stream infections.

CONCLUSIONS

Long-term survival in children with ultrashort bowel length is possible after referral to an intestinal failure program, although extensive medical management is required. These children may be reasonable candidates for long-standing intestinal rehabilitation as a bridge to intestinal transplantation.

Short-term intravenous fish oil and pediatric intestinal failure associated liver disease: 3-year follow-up on liver function and nutrition

Intravenous fish oil (FO) has changed the management of intestinal failure associated liver disease (IFALD). This report describes two IFALD patients who received FO for 5 and 10 months, respectively and reports on their 3-year follow-up.

Docosahexaenoic acid augments hypothermic neuroprotection in a neonatal rat asphyxia model

BACKGROUND

In neonatal rats, early post-hypoxia-ischemia (HI) administration of the omega-3 fatty acid docosahexaenoic acid (DHA) improves sensorimotor function, but does not attenuate brain damage.

OBJECTIVE

To determine if DHA administration in addition to hypothermia, now standard care for neonatal asphyxial brain injury, attenuates post-HI damage and sensorimotor deficits.

METHODS

Seven-day-old (P7) rats underwent right carotid ligation followed by 90 min of 8% O2 exposure. Fifteen minutes later, pups received injections of DHA 2.5 mg/kg (complexed to 25% albumin) or equal volumes of albumin. After a 1-hour recovery, pups were cooled (3 h, 30°C). Sensorimotor and pathology outcomes were initially evaluated on P14. In subsequent experiments, sensorimotor function was evaluated on P14, P21, and P28; histopathology was assessed on P28.

RESULTS

At P14, left forepaw function scores (normal: 20/20) were near normal in DHA + hypothermia-treated animals (mean ± SD 19.7 ± 0.7 DHA + hypothermia vs. 12.7 ± 3.5 albumin + hypothermia, p < 0.0001) and brain damage was reduced (mean ± SD right hemisphere damage 38 ± 17% with DHA + hypothermia vs. 56 ± 15% with albumin + hypothermia, p = 0.003). Substantial improvements on three sensorimotor function measures and reduced brain damage were evident up to P28.

CONCLUSION

Unlike post-HI treatment with DHA alone, treatment with DHA + hypothermia produced both sustained functional improvement and reduced brain damage after neonatal HI.

Pathogenesis and treatment of parenteral nutrition-associated liver disease

BACKGROUND

Parenteral nutrition-associated liver disease (PNALD) has been common in patients who require long-term parenteral nutrition. PNALD develops in 40%-60% of infants on long-term parenteral nutrition compared with 15%-40% of adults on home parenteral nutrition for intestinal failure. The pathogenesis of PNALD is multifactorial and remains unclear. There is no specific treatment. Management strategies for its prevention and treatment depend on an understanding of many risk factors. This review aims to provide an update on the pathogenesis and treatment of this disease.

DATA SOURCES

A literature search was performed on the MEDLINE and Web of Science databases for articles published up to October 2011, using the keywords: parenteral nutrition associated liver disease, intestinal failure associated liver disease, lipid emulsions and fish oil. The available data reported in the relevant literatures were analyzed.

RESULTS

The literature search provided a huge amount of evidence about the pathogenesis and management strategies on PNALD. Currently, lack of enteral feeding, extended duration of parenteral nutrition, recurrent sepsis, and nutrient deficiency or excess may play important roles in the pathogenesis of PNALD. Recent studies found that phytosterols, present as contaminants in soy-based lipid emulsions, are also an important factor in the pathogenesis. Moreover, the treatment of PNALD is discussed.

CONCLUSIONS

The use of lipid emulsions, phytosterols in particular, is associated with PNALD. Management strategies for the prevention and treatment of PNALD include consideration of early enteral feeding, the use of specialized lipid emulsions such as fish oil emulsions, and isolated small bowel or combined liver and small bowel transplantation. A greater understanding of the pathogenesis of PNALD has led to promising interventions to prevent and treat this condition. Future work should aim to better understand the mechanisms of PNALD and the long-term outcomes of its treatment.

The use of fish oil lipid emulsion in the treatment of intestinal failure associated liver disease (IFALD)

Since 2004, fish oil based lipid emulsions have been used in the treatment of intestinal failure associated liver disease, with a noticeable impact on decreasing the incidence of morbidity and mortality of this often fatal condition. With this new therapy, however, different approaches have emerged as well as concerns about potential risks with using fish oil as a monotherapy. This review will discuss the experience to date with this lipid emulsion along with the rational for its use, controversies and concerns.

Fish oil emulsions in the management of intestinal failure-associated liver disease

The role of parenteral lipid emulsions in the treatment of intestinal failure-associated liver disease (IFALD) is both topical and controversial. There is strong evidence supporting plant-based (soy, olive) lipid emulsions as a key cause for IFALD, especially in neonates. As a result, alternate lipid formulations, most notably fish oil emulsions (FOE) have come into widespread use despite somewhat limited clinical data on their overall benefit and potential long-term consequences. This review examines putative mechanisms of action of FOE in reversing cholestasis associated with IFALD, and critically reviews published clinical studies of the use of FOE in pediatric patients with IFALD. From these works, it appears the mechanism of action of FOE is most likely related to the reduction of serum phytosterols associated with plant-based lipid emulsions rather than a specific positive benefit of the fish oils themselves. Although the use of FOE seems to correlate with a reduction in cholestasis, their actual individual benefit is not established, and data on long-term outcomes and safety are not yet available.

Review and clinical update on parenteral nutrition-associated liver disease

Parenteral nutrition-associated liver disease (PNALD) is a complex disease that is diagnosed by clinical presentation, biochemical markers of liver injury, concurrent use of parenteral nutrition (PN), and negative workup for other causes of liver disease. Since the first case of PNALD was reported more than 30 years ago, clinicians have had few effective treatments for PNALD, and when disease progressed to liver cirrhosis, it was historically associated with poor outcomes. Within the past 5 years, there has been much excitement about new treatments for PNALD, including use of both parenteral and enteral ω-3 polyunsaturated long-chain fatty acids (ω-3 PUFA) as well as restricting dosing of ω-6 PUFA. Scientists are also interested in uncovering the mechanisms associated with liver injury seen in PNALD. This article reviews the recent literature relating to the pathophysiology and treatment of PNALD.

Effect of an omega-3 lipid emulsion in reducing oxidative stress in a rat model of intestinal ischemia-reperfusion injury

OBJECTIVES

The usefulness of omega-3 lipid emulsions has been extensively studied. The objectives of the present study were to examine the effect of an omega-3 lipid emulsion in reducing oxidative stress in a rat model of intestinal ischemia-reperfusion injury and the underlying mechanism.

METHODS

A total of 66 rats were divided into three dietary groups (lipid-free, soybean oil, and fish oil groups). Each animal was administered total parenteral nutrition for 3 days, followed by induction of intestinal ischemia for 100 min. Animals subjected to sham surgery served as the controls. Intestinal tissue and blood were harvested 6 and 12 h after the surgery, then, assessment of the histological damage score, plasma-related parameters, and statistical evaluation were performed.

RESULTS

The histological damage score in the intestinal tissues was significantly lower in the fish oil group than in the soybean oil group (P = 0.0121). The late-phase urinary level of 8-hydroxy-2-deoxyguanosine was also significantly lower in the fish oil group as compared with that in the other groups (P = 0.0267). Furthermore, the plasma level of high-mobility group box 1 protein was also significantly lower in the fish oil group as compared with that in the lipid-free group (P = 0.0398).

CONCLUSION

It appeared that intravenous administration of an omega-3 lipid emulsion prior to ischemia-reperfusion injury reduced the oxidative stress and severity of tissue damage. Modification of membrane fatty acids may serve as the mechanism underlying this reduction of tissue damage.

Intestinal transplantation: a review

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. Intestinal transplantation is now recognized as a treatment for patients who develop complications of parenteral nutrition and in whom attempts at intestinal rehabilitation have failed. Patients with parenteral nutrition related liver disease will require a liver graft typically part of a multivisceral transplant. Isolated intestinal transplants are more commonly performed in adults while multivisceral transplants are most commonly performed in infants. Isolated intestinal transplants have the best short-term outcome, with over 80 % survival at 1 year. Patients requiring multivisceral transplants have a high rate of attrition with a 1 year survival less than 70 %. Prognostic factors for a poor outcome include patient hospitalization at the time of transplant and donor age greater than 40 years while systemic sepsis and acute rejection are the major determinant of early postoperative outcome. For patients surviving the first year the outcome of transplantation of the liver in addition to intestine affords some survival advantage though long-term outcome does not yet match other abdominal organs. Outcomes for intestinal retransplantation are poor as a result of immunology and patient debility. Overall intestinal transplantation continues to develop and is a clear indication with cost and quality of life advantages in patients with intestinal failure that do not remain stable on parenteral nutrition.

Implementation of a multidisciplinary team approach and fish oil emulsion administration in the management of infants with short bowel syndrome and parenteral nutrition-associated liver disease

OBJECTIVE

To describe the authors' experience with the implementation of a multidisciplinary approach and use of fish oil emulsion (FOE) in the management of infants with short bowel syndrome (SBS) and parenteral nutrition-associated liver disease (PNALD).

METHODS

Between August 2006 and June 2009, four cases of SBS and severe PNALD were managed by the team using specifically developed protocols. The FOE was initiated if serum direct bilirubin levels were ≥100 µmol/L. To quantify the degree of exposure to high serum direct bilirubin levels over time, the area under the curve (AUC) for each patient was calculated before and after initiation of FOE. Linear regression analyses were performed to evaluate correlations between the AUC, duration of cholestasis and initiation of FOE.

RESULTS

All patients survived and no complications were observed during the study period. After the first patient, FOE was initiated progressively earlier, but poor correlation between the AUC before and after its introduction was observed (r(2)=0.41924). However, there was strong correlation between the duration of PNALD before FOE initiation and time to resolution (r(2)=0.72133): the earlier the FOE was initiated, the shorter the time to resolution.

CONCLUSION

The authors report a positive experience with the implementation of a multidisciplinary approach and the use of FOE in infants with SBS and severe PNALD. The earlier the FOE was initiated during the cholestatic process, the shorter the time to resolution. The present study is a hypothesis generator, raising the question of whether an earlier introduction of this particular therapy can effectively shorten the cholestasis process in these patients.

Short bowel syndrome in children: current and potential therapies

Short bowel syndrome (SBS) reflects a state of malabsorption that occurs due to loss of a significant portion of the small bowel. The pathophysiology of SBS is determined largely by the process of adaptation, which is the innate attempt by the remnant portions of the intestine to increase fluid and nutrient reabsorption. In recent years, emphasis has been placed on intestinal rehabilitation with multidisciplinary teams as a comprehensive approach to the management of patients with SBS. In our institution, the multidisciplinary team members include pediatric gastroenterologists, pediatric surgeons, pediatric dieticians, physical therapists, occupational therapists, neonatologists (especially for patients still under their care), transplant surgeons, transplant coordinators and social workers. Parenteral nutrition plays a significant role in the management of SBS, but its use is associated with many potential complications, including cholestatic liver disease. Fish oil-based lipid emulsions have shown promise in their ability to reverse and also prevent the development of cholestasis in these patients. Clinical trials have shown that growth factors and other trophic hormones facilitate the process of adaptation. The most significant impact has been shown with the use of glucagon-like peptide-2 and its analog (teduglutide). Surgical interventions remain an important part of the management of SBS to facilitate adaptation and treat complications. Intestinal transplantation is a last resort option when the process of adaptation is unsuccessful. This review article is intended to provide an overview of the conventional and emerging therapies for pediatric SBS.

Resolution of parenteral nutrition-associated jaundice on changing from a soybean oil emulsion to a complex mixed-lipid emulsion

BACKGROUND AND OBJECTIVE

Resolution of parenteral nutrition (PN)-associated jaundice has been reported in children given a reduced dose of intravenous fat using a fish oil-derived lipid emulsion. The aim of the present study was to examine the effect on PN-associated jaundice of changing from a soybean oil-derived lipid to a mixed lipid emulsion derived from soybean, coconut, olive, and fish oils without reducing the total amount of lipid given.

METHODS

Retrospective cohort comparison examining serum bilirubin during 6 months in children with PN-associated jaundice who changed to SMOFlipid (n=8) or remained on Intralipid (n=9).

RESULTS

At entry, both groups received most of their energy as PN (SMOFlipid 81.5%, range 65.5-100 vs Intralipid 92.2%, range 60.3-100; P=0.37). After 6 months, both tolerated increased enteral feeding but still received large proportions of their energy as PN (SMOFlipid 68.4%, range 36.6-100 vs Intralipid 50%, range 37.6-76; P=0.15). The median bilirubin at the outset was 143 μmol/L (range 71-275) in the SMOFlipid group and 91 μmol/L (range 78-176) in the Intralipid group. After 6 months, 5 of 8 children in the SMOFlipid and 2 of 9 children in the Intralipid group had total resolution of jaundice. The median bilirubin fell by 99 μmol/L in the SMOFlipid group but increased by 79 μmol/L in the Intralipid group (P=0.02).

CONCLUSIONS

SMOFlipid may have important protective properties for the liver and may constitute a significant advance in PN formulation. Randomised trials are needed to study the efficacy of SMOFlipid in preventing PN liver disease.

Hepatic ultrastructure in a neonatal piglet model of intestinal failure-associated liver disease (IFALD)

This study was designed to evaluate liver disease in neonatal piglets with surgical short bowel syndrome causing intestinal failure with partial parenteral nutrition dependence. The short bowel piglets had 75% surgical resection of distal small intestine, including all ileum and cecum, and were compared with sham controls, without resection, and to healthy sow-reared controls. After 18 days of combined parenteral and enteral nutrition in short bowel and sham piglets, liver tissue was collected for quantitative and semi-quantitative histological and ultrastructural evaluation. The short bowel piglets developed biochemical and histological cholestasis, not observed in sham and control piglets. Ultrastructural examination revealed bile canaliculus dilation with bile plugging, microvillus flattening and disappearance, but without abnormalities of the pericanalicular zone. Interestingly, these data are similar to bile canaliculus changes seen in human neonates with IFALD supporting an initial consideration of this model to elucidate the pathogenesis of IFALD.

Incidence and risk factors of parenteral nutrition-associated liver disease in newborn infants

BACKGROUND

The aim of the present study was to determine the incidence and risk factors of parenteral nutrition-associated liver disease (PNALD) in neonates.

METHODS

A 1 year prospective cohort study was carried out at the neonatal intensive care unit and sick neonatal wards, Chiang Mai University Hospital. Newborns >1000 g, receiving >7 days of parenteral nutrition (PN), were enrolled. Liver function tests were done by the end of first, second, and fourth week, and then every 4 weeks until the PN was discontinued and the jaundice resolved. The diagnosis of PNALD relied on a history of PN, direct bilirubin >2 mg/dL, and exclusion of other causes of neonatal cholestasis. Selected patient factors and PN compositions were analyzed to determine the risks for development of PNALD.

RESULTS

A total of 24 infants with a mean gestational age and birthweight of 32.5 weeks and 1840 g were enrolled. Eight of the 24 developed PNALD. Compared to those without PNALD, gastrointestinal surgery, duration of enteral starvation, duration of PN, maximum PN caloric intake, and maximum carbohydrate intake were significantly associated with the development of liver disease. Despite the lack of statistical significance, there was a trend towards cholestasis in patients with sepsis. Elevation of direct bilirubin was the earliest biochemical change, observed in the first week after PN, followed by increased transaminases.

CONCLUSION

Gastrointestinal surgery, duration of enteral starvation, duration of PN, maximum caloric and carbohydrate intake in PN were significant risks of PNALD in newborn infants.

Ethanol locks to prevent catheter-related bloodstream infections in parenteral nutrition: a meta-analysis

OBJECTIVE

Patients with pediatric intestinal failure (IF) depend on parenteral nutrition for growth and survival, but are at risk for complications, such as catheter-related bloodstream infections (CRBSIs). CRBSI prevention is crucial, as sepsis is an important cause of IF-associated liver disease and mortality. We aim to estimate the pooled effectiveness and safety of ethanol locks (ELs) in comparison with heparin locks (HLs) with regard to CRBSI rate and catheter replacements for pediatric IF patients with chronic parenteral nutrition dependence.

METHODS

A systematic review without language restriction was performed on Medline (1948-2010), Embase (1980-2010), and conference programs and trial registries up to December 2010. Search terms included "Catheter-Related Infections," "Catheter," "Catheters, Indwelling," "alcohol," "ethanol," and "lock." Two authors identified 4 retrospective studies for the pediatric IF population. Double, independent data extraction using predefined data fields and risk of bias assessment (Newcastle-Ottawa scale) was performed.

RESULTS

In comparison with HLs, ELs reduced the CRBSI-rate per 1000 catheter days by 7.67 events and catheter replacements by 5.07. EL therapy decreased the CRBSI rate by 81% and replacements by 72%. One hundred eight to 150 catheter days of EL exposure were necessary to prevent 1 CRBSI and 122 to 689 days of exposure avoided 1 catheter replacement. Adverse events were rare and included thrombotic events.

CONCLUSIONS

In pediatric patients with IF, EL is a more effective alternative to HL. Adverse events include thrombotic events.

Improved outcome in neonatal short bowel syndrome using parenteral fish oil in combination with ω-6/9 lipid emulsions

BACKGROUND

Newborn infants with short bowel syndrome (SBS) represent a high-risk group of developing intestinal failure-associated liver disease (IFALD), which may be fatal. However, infants have a great capacity for intestinal growth and adaptation if IFALD can be prevented or reversed. A major contributing factor to IFALD may be the soybean oil-based intravenous lipid emulsions used since the introduction of parenteral nutrition (PN) 40 years ago.

METHODS

This retrospective study compares the outcome in 20 neonates with SBS treated with parenteral fish oil (Omegaven) in combination with ω-6/9 lipid emulsions (ClinOleic) with the outcome in a historical cohort of 18 patients with SBS who received a soybean oil-based intravenous lipid emulsion (Intralipid).

RESULTS

Median gestational age was 26 weeks in the treatment group and 35.5 weeks in the historical group. All patients were started on PN containing Intralipid that was switched to ClinOleic/Omegaven in the treatment group at a median age of 39 gestational weeks. In the treatment group, direct bilirubin levels were reversed in all 14 survivors with cholestasis (direct bilirubin >50 umol/L). Median time to reversal was 2.9 months. Only 2 patients died of liver failure (10%). In the historical cohort, 6 patients (33%) died of liver failure, and only 2 patients showed normalization of bilirubin levels.

CONCLUSIONS

Parenteral fish oil in combination with ω-6/9 lipid emulsions was associated with improved outcome in premature neonates with SBS. When used instead of traditional soybean-based emulsions, this mixed lipid emulsion may facilitate intestinal adaptation by increasing the IFALD-free period.

Short-term use of parenteral nutrition with a lipid emulsion containing a mixture of soybean oil, olive oil, medium-chain triglycerides, and fish oil: a randomized double-blind study in preterm infants

BACKGROUND

For premature neonates needing parenteral nutrition (PN), a balanced lipid supply is crucial. The authors hypothesized that a lipid emulsion containing medium-chain triglycerides (MCTs) and soybean, olive, and fish oils would be as safe and well tolerated as a soybean emulsion while beneficially influencing the fatty acid profile.

METHODS

Double-blind, controlled study in 53 neonates (<34 weeks' gestation) randomized to receive at least 7 days of PN containing either an emulsion of MCTs and soybean, olive, and fish oils or a soybean oil emulsion. Target lipid dosage was 1.0 g fat/kg body weight [BW]/d on days 1-3, 2 g/kg BW/d on day 4, 3 g/kg BW/d on day 5, and 3.5 g/kg BW/d on days 6-14.

RESULTS

Test emulsion vs control, mean ± SD: baseline triglyceride concentrations were 0.52 ± 0.16 vs 0.54 ± 0.19 mmol/L and increased similarly in both groups to 0.69 ± 0.38 vs 0.67 ± 0.36 on day 8 of treatment (P = .781 for change). A significantly higher decrease in total and direct bilirubin vs baseline was seen in the test group compared with the control group P < .05 between groups). In plasma and red blood cell phospholipids, eicosapentaenoic acid and docosahexaenoic acid were higher, and the n-6/n-3 fatty acid ratio was lower in the test group (P < .05 vs control).

CONCLUSIONS

The lipid emulsion, based on a mixture of MCTs and soybean, olive, and fish oils, was safe and well tolerated by preterm infants while beneficially modulating the fatty acid profile.

Use of an omega-3 fatty acid-based emulsion in the treatment of parenteral nutrition-induced cholestasis in patients with microvillous inclusion disease

Microvillous inclusion disease is a congenital intestinal epithelial cell disorder leading to lifelong intestinal failure. In this report, we discuss the use of a fish oil-based lipid emulsion in the treatment of 3 patients with microvillous inclusion disease who developed parenteral nutrition-associated liver disease.

Effect of omega-3 polyunsaturated fatty acids to reverse biopsy-proven parenteral nutrition-associated liver disease in adults

BACKGROUND & AIMS

Parenteral nutrition-associated liver disease (PNALD) complicates the treatment of patients with short bowel syndrome (SBS). Some studies have shown omega-3 polyunsaturated fatty acids (ω-3 PUFAs) have favorable effects in treating PNALD in children. We, therefore, investigate the effects of ω-3 PUFAs supplemented intravenous lipid emulsion (ILE) on PNALD in adults.

METHODS

We performed an open-labeled study of a ω-3 PUFAs based ILE in 15 adults with SBS who developed cholestasis while receiving soybean oil-based ILE. Liver biopsies were performed before and after the initiation of ω-3 PUFAs to confirm the presence and improvement of cholestasis. Blood samples were collected every week for analysis of fatty acid composition and liver function.

RESULTS

12 of the 15 patients had their direct bilirubin normalized within 4 weeks and our data demonstrated a significant decrease in both DB (P ≤ 0.001) and TB (P ≤ 0.001) after 4 weeks compared to baseline. There were ameliorations of liver function and fatty acid patterns in all patients and serial liver biopsy specimens showed progressive histologic improvement.

CONCLUSIONS

Parenteral ω-3 PUFAs supplemented fat emulsions are safe and effective in the treatment of PNALD in adults.

A contemporary analysis of parenteral nutrition-associated liver disease in surgical infants

BACKGROUND/PURPOSE

Despite advances in pediatric nutritional support and a renewed focus on management of intestinal failure, there are limited recent data regarding the risk of parenteral nutrition (PN)-associated liver disease in surgical infants. This study investigated the incidence of cholestasis from PN and risk factors for its development in this population.

METHODS

A retrospective review was performed of all neonates in our institution who underwent abdominal surgery and required postoperative PN from 2001 to 2006. Cholestasis was defined as 2 conjugated bilirubin levels greater than 2 mg/dL over 14 days. Nonparametric univariate analyses and multivariate logistic regression were used to model the likelihood of developing cholestasis. Median values with range are presented.

RESULTS

One hundred seventy-six infants met inclusion criteria, and patients received PN for 28 days (range, 2-256 days). The incidence of cholestasis was 24%. Cholestatic infants were born at an earlier gestational age (34 vs 36 weeks; P < .01), required a 3-fold longer PN duration (76 vs 21 days; P < .001), had longer inpatient stays (86 vs 29 days; P < .001), and were more likely to be discharged on PN. The median time to cholestasis was 23 days. Cholestasis was an early development; 77% of cholestatic infants developed cholestasis by 5 weeks of PN exposure. On multivariate regression, only prematurity was significantly associated with development of cholestasis (P < .05).

CONCLUSION

In this analysis, the development of PN-associated liver disease occurred early in the course of exposure to PN. These data help to define the time course and prognosis for PN-associated cholestasis in surgical infants.

The role of parenteral lipids in the development of advanced intestinal failure-associated liver disease in infants: a multiple-variable analysis

BACKGROUND

Given the recent interest in the role of ω-6 lipids in the development of intestinal failure-associated liver disease (IFALD), the authors sought to examine the role of parenteral lipids in the development of a serum conjugated bilirubin >100 µmol/L (5.9 mg/dL; CB100) in infants.

METHOD

Between 2003 and 2004, data were collected prospectively on infants undergoing an abdominal surgical procedure. Univariate logistic regression models for the prediction of CB100 by 1 year postoperatively were developed. Predictors significant at the 0.2 level on univariate analysis were entered into a backward stepwise multiple variable logistic regression.

RESULTS

Of 152 infants who received parenteral nutrition (PN) postoperatively, 22 developed CB100. Predictors that met criteria for consideration in the multiple-variable model were age, weight, small bowel length, presence of a stoma, proportion of enteral feeds postoperatively, septic episodes, days of maximal PN amino acid (>2.5 g/kg/d), days of maximal lipid (>2.5 g/kg/d), and PN duration. The final model included septic episodes (odds ratio, 3.23; 95% confidence interval, 1.8-5.9) and days of lipid >2.5 g/kg/d (1.04; 1.003-1.06). At 60 days of maximal lipid, the odds of advanced IFALD were increased 10-fold.

CONCLUSIONS

This model suggests a key role of parenteral lipids and septic events in the development of CB100 from IFALD. These data may provide targets, such as careful line care, reduction in maximal lipid dose, or alternate lipids such as ω-3 fatty acids, to prevent CB100, an identified marker of subsequent liver failure from IFALD.

Prevention and reversal of intestinal failure-associated liver disease in premature infants with short bowel syndrome using intravenous fish oil in combination with omega-6/9 lipid emulsions

Although premature infants with short bowel syndrome are at the highest risk of developing intestinal failure-associated liver disease (IFALD), they have great capacity for intestinal growth and adaptation if IFALD can be prevented. Conventional soybean oil-based intravenous lipid emulsions have been associated with IFALD. This study presents data on 5 premature neonates with short bowel syndrome treated with a combination of parenteral fish oil- and olive/soybean-based lipid emulsion for periods ranging between 7 and 17 months. Despite an enteral tolerance of less than 50% in 4 of these patients during their first year of life, direct bilirubin levels normalized while on this combination of ClinOleic (Baxter, Maurepas, France)/Omegaven (Fresenius Kabi, Bad Homburg, Germany) at a 1:1 ratio. None of our patients developed irreversible IFALD even though all of them were premature, had undergone multiple major surgical procedures, and had experienced several episodes of sepsis. Thus far, we have not seen any adverse effects of this mixed lipid emulsion in these preterm infants. All 5 patients are growing and developing well and have normal liver function.

The optimal timing of referral to an intestinal failure program: the relationship between hyperbilirubinemia and mortality

PURPOSE

Multidisciplinary treatment of pediatric intestinal failure has shown promising results. However, there are limited data as to the optimal time frame for referral of patients to intestinal failure programs. The aim of this study was to explore the relationship of hyperbilirubinemia at referral with patient outcomes in a multidisciplinary program.

METHODS

A retrospective analysis was performed of a prospectively collected database from a multidisciplinary intestinal failure program. Multivariable logistic regression adjusted for age at referral was used to model the association between the conjugated bilirubin at referral and risk of mortality. Median values with range are reported.

RESULTS

Sixty-two patients were referred from 2005 to 2009. Patients presented at age 6.4 months (0.4-261.4 months) and were followed up for 16.8 (0.3-53.0) months. Nine subjects (14.5%) died, and 12 subjects (19.4%) were listed for combined liver-intestine transplant. A 50% mortality was seen in patients referred with a conjugated bilirubin ≥ 7.2 mg/dL (n = 12), whereas mortality at referral bilirubin levels <7.2 mg/dL was 6%. After adjusting for age at referral, patients with a conjugated bilirubin ≥ 7.2 mg/dL at referral were 15.4 times more likely to die than patients who presented with lower bilirubin levels (P = .001; 95% confidence interval, 2.8-83.4).

CONCLUSION

Within a pediatric intestinal failure program, mortality is associated with the degree of hyperbilirubinemia at time of referral. These data strongly suggest that these patients should be referred to a multidisciplinary program early in the evolution of their liver disease.

The use of Omegaven in treating parenteral nutrition-associated liver disease

Parenteral nutrition (PN), containing fat emulsions derived from soybean, has been implicated in the progression of PN-associated liver disease and cholestasis, particularly in infants with short bowel syndrome. Clinical use of Omegaven, a parenteral fish-oil emulsion, has been shown in recent studies to be a promising therapy to reverse liver disease and cholestasis. This review summarizes the rationale, relevant clinical investigations and future direction of Omegaven therapy for PN-dependent infants.

Lipids for parenteral nutrition in neonates

PURPOSE OF REVIEW

In neonatal intensive care units, the interest and scope for research in the field of intravenous lipids has significantly widened in recent years. This brief review covers the advances in this field in the last 2 years.

RECENT FINDINGS

These include a significant amount of research in evaluating safety and efficacy of novel lipid emulsions that include olive oil or fish oil. Short-term studies involving novel lipid emulsions have documented safety and benefits in terms of reduced inflammation and lipid peroxidation. Fish oil-based lipid emulsions have also been used to prevent and treat parenteral nutrition-induced cholestasis. Other areas of progress include stability studies of all-in-one parenteral nutrition mixtures including lipid emulsions for neonates.

SUMMARY

Since the first soybean oil-based lipid emulsions were introduced 50 years ago, progress has been made in understanding the composition, dose and clinical effects of parenteral lipids in neonatal patients. However there is a paucity of data in terms of definitive head-to-head trials of different novel lipid emulsions evaluating short-term as well as long-term clinically important outcomes including neurodevelopment. Future research is required to determine long-term benefits of novel lipid emulsions for neurological outcome and effects on the immune system.

Safety and efficacy of fish oil-enriched parenteral nutrition regimen on postoperative patients undergoing major abdominal surgery: a meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the safety and efficacy of a fish oil-enriched parenteral nutrition regimen in patients undergoing major abdominal surgery, a meta-analysis of randomized controlled trials was conducted.

METHODS

An electronic search of PubMed, MEDLINE, EMBASE, Academic Search Premier, and China National Knowledge Infrastructure databases was performed in March 2009. RevMan 5.0 was used for statistical analysis.

RESULTS

The combined analysis showed that a fish oil-enriched parenteral nutrition regimen had a positive treatment effect on length of hospital stay (weighed mean difference = -2.98, P < .001), length of intensive care unit stay, postoperative infection rate (odds ratio = 0.56, P = .04), and serum levels of aspartate aminotransferase, alanine aminotransferase, and alpha-tocopherol on postoperative day 6 in these patients. The regimen increased the plasma levels of eicosapentaenoic acid (standardized mean difference = 3.11, P < .001) and docosahexaenoic acid and upregulated the leukotriene B(5) production in leukocytes on postoperative day 6. No significant differences were found between the 2 groups in postoperative mortality; incidence of postoperative cardiac complications; serum levels of bilirubin, triglyceride, or arachidonic acid; or the liberation of leukotriene B(4). No serious adverse events related to fish oil treatment were reported.

CONCLUSIONS

Based on the meta-analysis, fish oil-supplemented parenteral nutrition was safe, improved clinical outcomes, and altered the fatty acid pattern as well as leukotriene synthesis. More laboratory parameters should be considered in future meta-analyses.

Systematic review: medical and nutritional interventions for the management of intestinal failure and its resultant complications in children

BACKGROUND

Intestinal failure (IF) affects a growing number of children due to increasing numbers of preterm infants surviving intestinal resection for necrotising enterocolitis and improving surgical techniques for congenital gut anomalies. Parenteral nutrition (PN) is the mainstay of therapy; enteral nutrition may have trophic effects on the gut.

AIM

To review systematically evidence for the effectiveness of medical and nutritional interventions in the treatment of IF in children.

METHODS

Retrieval of data from studies of patients aged <18 years and receiving >28 days of PN. Outcome measures were improvement in intestinal function, intestinal adaptation, growth, prevention and treatment of IF-associated liver disease, and mortality. Cochrane Database (November 2009), MEDLINE (1950-November 2009) and CINAHL (1982-November 2009) electronic database searches were made using keyword and subject headings (MeSH): IF, Short Bowel Syndrome (SBS), PN and Child. The level of the evidence (EL) was assessed using SIGN (Scottish Intercollegiate Guidelines Network) methodology (http://www.sign.ac.uk).

RESULTS

From 1 607 620 hits, 720 abstracts were reviewed. Thirty-three original articles were included. No studies were of high methodological quality.

CONCLUSIONS

The evidence base for medical and nutritional interventions in paediatric IF is limited and of poor quality. In the absence of randomised-controlled trials, this evidence base can improve through case control and cohort research; and with better multiagency communication, the study of inter-centre differences is possible. Achievable short-term goals would include the study of: optimal ursodeoxycholic usage, novel intralipid formulations, cycled enteral antibiotics, enteral probiotics and new enteral feeding strategies.

Surgical intervention in the setting of parenteral nutrition-associated cholestasis may exacerbate liver injury

PURPOSE

This study compares postoperative markers of liver injury in patients receiving intravenous fish oil (IFO) with parenteral nutrition (PN)-associated cholestasis (PNAC) to patients with resolved PNAC.

METHODS

A retrospective review of all cholestatic-IFO patients undergoing abdominal laparotomy between March 1, 2007, and July 1, 2009, led to inclusion of 23 patients who collectively underwent 27 abdominal operations (13 pre-PNAC resolution and 14 post-PNAC resolution). Direct bilirubin (DB), total bilirubin, and alanine aminotransferase levels were examined over time in relation to operations. The time to resume presurgical trend of decreasing DB was calculated.

RESULTS

Sixty-nine percent (9/13) of pre-PNAC resolution procedures were associated with postoperative increase in DB compared with 7% (1/14) of post-PNAC resolution procedures associated with a recurrence of cholestasis (P = .02; odds ratio, 29.3; 95% confidence interval, 2.79-306.8). The median time to return to the preoperative downward trend of DB was 21 days.

CONCLUSIONS

Operations before PNAC resolution may be associated with an increased postoperative DB, possibly reflecting an exacerbation of liver injury. Operations post-PNAC resolution on IFO had a comparatively low incidence of postoperative cholestasis recurrence. Excepting clinical indication otherwise, it may be advisable to delay surgical intervention in the setting of PNAC in certain cases.

Omega-3 Long Chain Polyunsaturated Fatty Acids for Treatment of Parenteral Nutrition–Associated Liver Disease: A Review of the Literature

Parenteral nutrition–associated liver disease (PNALD) is a complex disease that is diagnosed by clinical presentation, biochemical markers of liver injury, concurrent use of parenteral nutrition (PN), and negative workup for other causes of liver disease. For the past 30 years, clinicians have had few effective treatments for PNALD and when disease progressed to liver cirrhosis it was historically associated with poor outcomes. Within the past 5 years there has been some encouraging evidence for the potential benefits of fish oils, rich in omega-3 long-chain polyunsaturated fatty acids (ω3PUFA), in reversing liver injury associated with PN. This article reviews the current literature relating to ω3PUFA and PNALD.

Elements of successful intestinal rehabilitation

PURPOSE

The optimal therapy for intestinal failure (IF) is unknown. The results of a systematic, protocol-driven management strategy by a multidisciplinary team are described.

METHODS

Intestinal failure was defined as bowel length of less than 40 cm or parenteral nutrition (PN) for more than 42 days. A multidisciplinary team and protocol to prevent PN-associated liver disease (PNALD) were instituted in 2006. Data were gathered prospectively with consent and ethics board approval.

RESULTS

From 1998 to 2006, 33 patients were treated (historical cohort) with an overall survival of 72%. Rotating prophylactic antibiotics for bacterial overgrowth were given to 27% of patients; 6% had lipid-sparing PN, and none received fish oil-based lipids. Median time to intestinal rehabilitation was 7 ± 3.1 months, and 27% of patients who developed PNALD died. From 2006 to 2009, 31 patients were treated. Seventy-seven percent received PAB; 60%, lipid-sparing PN; and 47%, parenteral fish oil emulsion. Eighty-seven percent weaned from PN at 3.9 ± 3.8 months, and no patients developed PNALD with 100% survival. Novel lipid therapies were associated with changes in essential fatty acid profile and one case of clinical essential fatty acid deficiency.

CONCLUSION

The institution of a multidisciplinary team and a protocol-driven strategy to prevent PNALD improves survival in IF. Further studies are recommended.