Original Article
Surgical Findings in Transfusion-Associated Necrotizing Enterocolitis Rosa Fonseca1
Lucía Mangas1
1 Department of Pediatric Surgery, Hospital Universitario y Politecnico
La Fe, Valencia, Spain Eur J Pediatr Surg
Abstract
Keywords
► necrotizing enterocolitis ► blood transfusion ► surgery ► patient acuity
Address for correspondence Miguel Couselo, MD, Department of Pediatric Surgery, Hospital Universitario y Politecnico La Fe. Av. Fernando Abril Martorell 106, 46026, Valencia, Spain (e-mail: [email protected]).
Introduction The extent of intestinal damage in transfusion-associated necrotizing enterocolitis (TNEC) has been scarcely studied. The aim of this investigation was to study surgical findings in TNEC and determine their severity considering the extent of the disease and risk of bowel perforation. Materials and Methods Neonates who required surgical treatment for necrotizing enterocolitis (NEC) were studied retrospectively. Patients who developed NEC within 48 hours after a red blood cell transfusion (RBCT) formed group TR48 and patients who did not receive a RBCT 48 hours before the diagnosis of NEC became group CN (conventional NEC). Both groups were compared: main outcomes were the extent of the disease (isolated, multifocal, or panintestinal), the existence of perforated NEC, and mortality. Categorical variables were analyzed with the chi-square test and continuous variables with the Mann–Whitney U-test. The relationship between RBCTs 48 hours before the diagnosis and the extent of intestinal disease was evaluated by ordinal logistic regression. Results Forty-seven patients were included in the study: 16 patients in TR48 and 31 in CN. The odds ratio of multifocal or panintestinal NEC for patients in TR48 was 0.5 (95% CI: 0.148–1.68). Neonates in TR48 had a relative risk (RR) of perforated NEC of 1.2 (95% CI: 0.76–1.85). The RR of death was 1.55 (95% CI: 0.76–3.14) in group TR48. Conclusion No differences in surgical findings between TR48 and CN could be demonstrated in this investigation; therefore, the hypothesis that intestinal damage might be more severe in TNEC was not confirmed.
Introduction The association between red blood cell transfusions (RBCTs) and necrotizing enterocolitis (NEC) was first reported by McGrady in a cluster of NEC cases in 1987.1 Afterwards, several studies proposed RBCTs as a risk factor for the development of NEC in premature neonates.2–4 Results from a recent meta-analysis based on published retrospective works supported this relationship.5 RBCTs in premature neonates have been associated with different comorbidities, such as retinopathy of prematurity,
received January 27, 2015 accepted after revision March 30, 2015
Juan José Vila1
intraventricular hemorrhage, or NEC.6,7 Oxidative and immunologic mechanisms have been proposed to explain the chain of events between the transfusion and those complications.6,8 The term TRAGI (transfusion-related acute gastrointestinal injury) was created to describe the development of intestinal damage because of RBCTs.4 This expression is analogous to TRALI (transfusion-related acute lung injury), a well-defined entity which causes noncardiogenic pulmonary edema within 6 hours after a blood transfusion.9,10 The pathogenesis of TRAGI is usually explained using the “two hit hypothesis”: in the first hit, vulnerable patients such as premature neonates
© Georg Thieme Verlag KG Stuttgart · New York
DOI http://dx.doi.org/ 10.1055/s-0035-1552570. ISSN 0939-7248.
Downloaded by: Rutgers University. Copyrighted material.
Miguel Couselo1
Couselo et al.
would be exposed to several factors which could activate endothelial cells in the intestine, such as early exposure to antigens in feedings, hypoxemia because of lung disease or infections; in the second hit, the antigens from the donor’s blood would provoke an immunologic response from the previously activated cells. This response would be amplified and cause damage in the mucosal barrier leading to NEC. 11 Transfusion-associated necrotizing enterocolitis (TNEC) is commonly defined as an episode of NEC which occurs within 48 hours after a RBCT. The severity of TNEC has not been clearly determined. On the one hand, according to some investigations TNEC could be a particular type of the disease characterized by an aggressive course and poorer outcomes.2,12,13 On the other hand, there might be no differences in clinical severity of TNEC once the disease is established.4 Nevertheless, to our knowledge, the extent and type of bowel involvement in these patients has not been studied yet. Given the importance of the length of bowel injuries in the prognosis of NEC, assessing both features could help to elucidate if TNEC is really a more severe or fulminant disease which would need a careful and thorough follow-up once the symptoms appear.
Materials and Methods A retrospective investigation of patients diagnosed with NEC between 2002 and 2014 was conducted. The research comprised neonates 34 weeks of gestational age. Cases with congenital heart disease were excluded to avoid possible bias because of hypoxia of this origin. Only neonates with NEC who underwent a laparotomy were included for the analysis. With the intention of excluding other causes of intestinal perforation, the definite diagnosis of NEC was confirmed according to three criteria: clinical data, surgical findings, and histologic reports. Patients with Bell stage I were not studied. Surgical findings were based on the surgeon’s visual inspection of the bowel at the time of surgery. NEC was identified when one or more of these features were found in the absence of obstructive causes: pneumatosis, ischemic injury, gangrene, or perforation. Finally, the histologic study was used to rule isolated intestinal perforations out of the investigation: NEC diagnosis was accepted if there was intense mucosal injury with coagulative or hemorrhagic necrosis. Two groups were considered for this research: TR48 was formed by those patients who had received a RBCT 48 hours before the diagnosis of NEC; patients with NEC who had not been treated with a RBCT 48 hours before the diagnosis became a part of group CN (conventional NEC). The first moment in which a member of the neonatal intensive care unit (NICU) or the neonatology unit evaluated a neonate because of symptoms which corresponded with NEC was considered the time of the diagnosis. RBCTs were administered according to hematocrit levels and clinical status of patients following the criteria of the responsible staff member from the NICU or the neonatology unit. Packed red blood cells were obtained and processed European Journal of Pediatric Surgery
following our institution Blood Bank protocol. This protocol includes irradiation, leukoreduction, preservation, and storage with SAG-mannitol at a temperature between 1 and 5°C. The main outcomes of this study were the features of bowel injuries because of NEC and mortality 90 days after the operation. The type and extent of bowel injuries were registered to evaluate the intestinal damage. The type of bowel injury was divided into the following categories: perforation (if any segment with complete disruption of the bowel wall or feces were found in the peritoneum), necrosis (when gangrene but not perforation was found), and pneumatosis (existence of air bubbles into the intestine wall). The extent of NEC was recorded as an ordinal variable with the following categories: focal NEC (isolated segment of less than 25% of intestinal length), multifocal NEC (two or more intestinal segments involving less than 50% of bowel length), and panintestinal NEC (majority of small and large bowel involved). Other variables recorded for each patient were birth weight, gestational age, 1st and 5th minute Apgar score, age when the symptoms of NEC appeared, hematocrit levels, treatments received before the diagnosis (not only in the previous 48 hours but from the date of admission until the diagnosis of NEC), and surgical treatment. Categorical variables were compared using the chi-square test or the Fisher exact test; relative risks (RR) of bowel perforation and mortality were obtained. The Mann–Whitney U-test was selected for continuous variables. Ordinal logistic regression (Polytomous Universal Model) was used to compare the extent of the disease: it provided a single estimative odds ratio (OR) for all the categories. This OR was calculated by exponentiation of the β coefficient. The statistical analysis was performed using the Statistical Package for Social Sciences (SPSS 17.0).
Results Forty-seven patients with gestational age 34 weeks underwent surgery because of NEC and formed the final sample of the study. Group TR48 consisted of 16 prematures (34%) who were treated with a RBCT 48 hours before the diagnosis of NEC, whereas group CN included 31 patients who did not receive a RBCT 48 hours before the onset of NEC symptoms (►Table 1). There were differences between both groups in gestational age, birth weight, Apgar scores (neonates from TR48 were smaller and with lower Apgar scores), and age at the diagnosis of NEC (patients from TR48 were older). Considering the time from birth to diagnosis, group TR48 was also different in the treatments administered before the diagnosis of NEC: these neonates received a higher number of RBCTs, more ibuprofen and ventilation support. Three patients in group CN and one patient in group TR48 had been operated on before the development of NEC for patent ductus arteriosus (PDA); another patient underwent surgery for an isolated intestinal perforation 3 weeks before the onset of NEC in group CN (a primary intestinal anastomosis was performed in that surgery).
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Surgical Findings in TNEC
Surgical Findings in TNEC
Couselo et al.
Table 1 Demographic and clinical characteristics of the sample TR48 (n ¼ 16)
p-Value
Gestational age (wk)
28 (26–30)
26 (24.5–27.5)
0.018
Birth weight (g)
995 (790–1250)
717 (617.5–850)
0.008
Age at the diagnosis of NEC (d)
9 (7.25–10.75)
13 (10–22)
0.024
1st min Apgar
8 (5–9)
4.5 (3–6)
0.02
5th min Apgar
9 (8–10)
7 (6.25–8)
0.003
Hematocrit after birth
44.3 (38.8–51)
44.2 (40.3–48.6)
0.97
Number of RBCTs before the diagnosis of NEC
1 (0–3)
2 (1.25–3.75)
0.042
Volume of RBCTs before the diagnosis of NEC (mL)
15 (0–29)
20 (13.5–37)
0.289
Hematocrit at the diagnosis of NEC
37.8 (30.6–41.8)
38.4 (35.2–40.3)
0.611
Gender (male)
18 (58.1%)
11 (68.8%)
0.54
Formula feeding
12 (38.7%)
5 (31.3%)
0.61
PDA
15 (48.4%)
13 (81.3%)
0.06
Ibuprofen
13 (41.9%)
12 (75%)
0.03
IVH grade 3
2 (6.5%)
2 (12.5%)
0.6
Ventilation support before the diagnosis of NEC
21 (70%)
15 (93.8%)
0.046
Vasopressor drugs before the diagnosis of NEC
12 (38.7%)
9 (56.3%)
0.25
Abbreviations: IVH, intraventricular hemorrhage; NEC, necrotizing enterocolitis; PDA, patent ductus arteriosus; RBCT, red blood cell transfusion. Note: Continuous variables are described by median, P25, and P75. Categorical variables are described by number of cases and percentage.
Data about RBCTs in the 48 hours before the diagnosis of NEC are presented in ►Table 2. Indications for surgical treatment are summarized in ►Table 3. A laparotomy was performed in all cases. Surgical findings are described in ►Table 4. The most frequent site of the disease was the small bowel in both groups and in a majority of the patients NEC was located in the ileum. Perforated NEC was found in 11 neonates who had been transfused 48 hours before the diagnosis (68.7%) and in 18 who had not received a transfusion in that period of time (58.1%). Therefore, the risk to develop perforated NEC in group TR48 was higher but nonsignificant (RR ¼ 1.2; 95% CI: 0.76–1.85; p ¼ 0.48). The overall probability of multifocal or panintestinal NEC was calculated using an ordinal logistic regression: the OR of developing advanced disease (multifocal or panintestinal) was 0.5 for patients in TR48 compared with those in CN, although this result was nonsignificant (95% CI: 0.148–1.68;
p ¼ 0.26). Cumulative ORs for each category of intestinal injury are showed in ►Table 5. The mortality rate after surgery in the whole sample was 38.3%. Eight deaths occurred in group TR48 (50%) and 10 deaths occurred in group CN (32.3%); the crude RR of death in TR48 was not statistically significant (RR ¼ 1.55; 95% CI: 0.76–3.14; p ¼ 0.24).
Discussion NEC usually appears in premature neonates, especially in those with very low birth weights.14 Similarly, these patients often need multiple RBCTs because of anemia of prematurity, hemorrhage, or frequent phlebotomies.15,16 According to other works, it is generally accepted that premature neonates with TNEC have lower gestational ages, lower birth weights, and a late age of presentation (approximately 3 or 4 weeks after birth).4,11,12,17–19 The first statements were confirmed in the present research; on the
Table 2 Transfusions administered in the interval of time of 48 hours before the diagnosis TR48 (n ¼ 16) Hematocrit before the transfusion
34.5 (31.3–38.1)
Volume of RBCT (mL)
10 (8.5–12.5)
Enteral feeding during the transfusion (%)
7 (43.7%)
Time elapsed from the end of the transfusion to the diagnosis of NEC (h)
34 (10.5–42)
Abbreviation: NEC, necrotizing enterocolitis; RBCT, red blood cell transfusion. Note: Continuous variables are described by median, P25, and P75. Categorical variables are described by number of cases and percentage. European Journal of Pediatric Surgery
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CN (n ¼ 31)
Couselo et al.
Table 3 Indications for surgical treatment of NEC CN (n ¼ 31)
TR48 (n ¼ 16)
Pneumoperitoneum (X-ray)
13 (41.9%)
7 (43.8%)
Fixed bowel loop (X-ray)
5 (16.1%)
3 (18.8%)
Gasless abdomen (X-ray)
5 (16.1%)
4 (25%)
Clinical impairment
8 (25.9%)
2 (12.4%)
Abbreviations: NEC, necrotizing enterocolitis.
contrary, the age at diagnosis was lower in the patients of this sample: 13 days in TR48. This investigation only included neonates who underwent surgical treatment for NEC: their age of presentation was similar to data published by Najaf (14 days at presentation of symptoms) and higher than the result given by Zhang (5.24 days at admission because of NEC) who performed studies which considered exclusive cases of NEC which received surgical therapy.20,21 Given that premature neonates with lower gestational ages and weights are prone to present multiples comorbidities, those cases with TNEC could be expected to develop severe illness before the onset of NEC.22,23 Patients in TR48 received more RBCTs, ibuprofen and respiratory support before the diagnosis: these facts reflect increased intensive care needs in this group. Although Mally reported a series of six healthy, stable neonates developing a fulminant form of NEC after receiving a RBCT, most works indicate that patients with TNEC are usually in worse clinical conditions before the onset of NEC.3,4,12,18 Thus, an accurate adjustment for clinical variables related to common comorbidities of low-birth-weight neonates is mandatory when investigations about TNEC show poorer outcomes in these patients. This adjustment was not performed in this work because there were no differences in major outcomes between the neonates classified as TNEC and those from group CN.
The percentage of patients with TNEC who require surgical treatment has not been clearly established.3,13 However, the main purpose of this investigation was not to determine the risk of surgery in TNEC but to study the surgical findings of neonates who developed NEC immediately ( 48 hours) after an RBCT. The most common finding in the whole sample of patients (TR48 and CN) was NEC with bowel perforation, which appeared in 61.7% of the neonates. This percentage is comparable to the 56% published previously by Najaf.20 Scarce data are available about the precise condition of bowel in TNEC; thus, it is only possible to infer the prevalence of perforated bowel in TNEC using markers of perforation, such as pneumoperitoneum, which is considered to be a very specific indicator of bowel disruption although it lacks sensitivity.24 El-Dib found a significant higher incidence of pneumoperitoneum in TNEC compared with conventional NEC (50 vs. 9.1%) although Josephson did not obtain statistical differences (40% in TNEC vs. 22%).3,25 In the present research, neonates in group TR48 had a higher risk of perforation compared with group CN. This fact could be taken as an indirect sign against the statement that clinical evolution of TNEC is characterized by a fulminant course.2,12,13 Focal NEC was found in more than half of the cases of both TR48 and CN. Multifocal disease was more frequent in TR48 and panintestinal NEC in CN. The result Cumulative OR TR48/ NTR which is exposed in ►Table 5 describes the influence of RBCTs in the extent of bowel injuries. It shows that focal NEC versus multifocal or panintestinal disease was 1.56 times more likely in group TR48 than in group CN. When focal or multifocal NEC versus panintestinal disease was analyzed, the cumulative OR was even higher, reaching 6.14. Logistic ordinal regression provided a single OR estimative for all the categories to summarize these two previous cumulative ORs: the probability of developing multifocal or panintestinal disease was 0.5 in TR48, which was statistically nonsignificant. Therefore, this investigation could not ascertain
Table 4 Surgical findings CN (n ¼ 31)
TR48 (n ¼ 16)
p-Value
18 (58.1%)
11 (68.75%)
0.18
Necrosis without perforation
12 (28.7%)
4 (25%)
0.27
Pneumatosis
1 (3.2%)
1 (6.25%)
0.56
Jejunum
0 (0%)
0 (0%)
–
Ileum
19 (61.3%)
11 (68.75%)
0.61
Colon
0 (0%)
1 (6.25%)
–
Jejunum þ ileum
3 (9.7%)
1 (6.25%)
0.57
Ileum þ colon
5 (16.1%)
2 (12.5%)
1
Jejunum þ ileum þ colon
4 (12.9%)
1 (6.25%)
0.32
Focal
16 (51.6%)
10 (62.5%)
–
Multifocal
6 (19.4%)
5 (31.25%)
Panintestinal
9 (29%)
1 (6.25%)
Findings Type of injury
Location
Extent of the disease
European Journal of Pediatric Surgery
Perforated bowel
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Surgical Findings in TNEC
Surgical Findings in TNEC
Couselo et al.
Table 5 Extent of bowel injuries: cumulative odds ratio Cumulative odds ratio in CN
Cumulative odds ratio in TR48
Cumulative odds ratio TR48/CN
Focal/multifocal or panintestinal
1.07
1.67
1.67/1.07 ¼ 1.56
Focal or Multifocal/panintestinal
2.44
15
15/2.44 ¼ 6.14
support the hypothesis that TNEC could be more severe regarding surgical findings.
Conflict of Interest The authors declare no conflict of interest.
References 1 McGrady GA, Rettig PJ, Istre GR, Jason JM, Holman RC, Evatt BL. An
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3
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5
6
7
8
9
10
11
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13
Conclusion No differences in the type and extent of bowel injuries could be demonstrated when TNEC and NEC unrelated to RBCTs were compared. The results of this investigation do not
14
outbreak of necrotizing enterocolitis. Association with transfusions of packed red blood cells. Am J Epidemiol 1987;126(6): 1165–1172 Christensen RD, Lambert DK, Henry E, et al. Is “transfusionassociated necrotizing enterocolitis” an authentic pathogenic entity? Transfusion 2010;50(5):1106–1112 Josephson CD, Wesolowski A, Bao G, et al. Do red cell transfusions increase the risk of necrotizing enterocolitis in premature infants? J Pediatr 2010;157(6):972–978.e1, 3 Blau J, Calo JM, Dozor D, Sutton M, Alpan G, La Gamma EF. Transfusion-related acute gut injury: necrotizing enterocolitis in very low birth weight neonates after packed red blood cell transfusion. J Pediatr 2011;158(3):403–409 Mohamed A, Shah PS. Transfusion associated necrotizing enterocolitis: a meta-analysis of observational data. Pediatrics 2012; 129(3):529–540 Del Vecchio A, Henry E, D’Amato G, et al. Instituting a program to reduce the erythrocyte transfusion rate was accompanied by reductions in the incidence of bronchopulmonary dysplasia, retinopathy of prematurity and necrotizing enterocolitis. J Matern Fetal Neonatal Med 2013;26(Suppl 2):77–79 Christensen RD. Associations between “early” red blood cell transfusion and severe intraventricular hemorrhage, and between “late” red blood cell transfusion and necrotizing enterocolitis. Semin Perinatol 2012;36(4):283–289 Wang-Rodriguez J, Fry E, Fiebig E, et al. Immune response to blood transfusion in very-low-birthweight infants. Transfusion 2000; 40(1):25–34 Benson AB, Austin GL, Berg M, et al. Transfusion-related acute lung injury in ICU patients admitted with gastrointestinal bleeding. Intensive Care Med 2010;36(10):1710–1717 Rashid N, Al-Sufayan F, Seshia MMK, Baier RJ. Post transfusion lung injury in the neonatal population. J Perinatol 2013;33(4): 292–296 La Gamma EF, Blau J. Transfusion-related acute gut injury: feeding, flora, flow, and barrier defense. Semin Perinatol 2012;36(4): 294–305 Mally P, Golombek SG, Mishra R, et al. Association of necrotizing enterocolitis with elective packed red blood cell transfusions in stable, growing, premature neonates. Am J Perinatol 2006;23(8): 451–458 Christensen RD, Wiedmeier SE, Baer VL, et al. Antecedents of Bell stage III necrotizing enterocolitis. J Perinatol 2010;30(1): 54–57 Hall NJ, Curry J, Drake DP, Spitz L, Kiely EM, Pierro A. Resection and primary anastomosis is a valid surgical option for infants with necrotizing enterocolitis who weigh less than 1000 g. Arch Surg 2005;140(12):1149–1151 European Journal of Pediatric Surgery
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differences between TR48 and CN when bowel injuries caused by NEC were evaluated. Overall mortality in this work was 38.3%; past reports about surgical treatment of NEC by laparotomy estimated that mortality could vary from 25 to 48%.2,26–29 When TR48 and CN were compared, neonates who had received a RBCT 2 days before the onset of NEC had a higher RR of death, which was statistically nonsignificant. A previous work published in 2010 by Christensen with neonates who underwent surgery found that mortality in neonates with NEC unrelated to transfusion was 28% and mortality in neonates with NEC following transfusion was 40%; likewise, these data showed no statistically significant differences. Panintestinal and multifocal disease are usually stated as major determinants of mortality in NEC.29–31 The analysis of mortality in this research was consistent with the results related to the length of affected bowel considering that differences between TR48 and NTR were not demonstrated. However, despite the fact that the RR for mortality was > 1 in TR48, the OR for advanced NEC was < 1 in TR48. A possible interpretation of this paradox could be that neonates in group TR48 were more immature and unstable: they had lower weight and gestational age, and needed more ventilation support. These features might have contributed to decreased survival rates.32 A common limitation in TNEC retrospective studies is that mild or subtle nondigestive symptoms might not be adequately recorded as part of the clinical onset of NEC; this would lead to inaccurate intervals between RBCTs and NEC. Another limitation in this investigation was the small sample size, which is a frequent characteristic in clinical studies about NEC; it might have caused that differences between the two groups (TR48 and CN) were not found. Finally, there were obvious subjective criteria in the assessment of the length of bowel affected by NEC. Although in some cases the injuries were measured and registered in centimeters, there were patients in whom this task was difficult because of multifocal disease or diffuse limits between healthy and slightly ischemic intestine. In an attempt to minimize this limitation, the extent NEC was considered as focal, multifocal, and panintestinal; however, this classification provided less precise information than numeric data.33,34 Consequently, the analysis of the extent of the disease was performed using ordinal logistic regression and cumulative ORs.
Couselo et al.
15 Venkatesh V, Khan R, Curley A, New H, Stanworth S. How we
16
17
18
19
20
21
22
23
decide when a neonate needs a transfusion. Br J Haematol 2013; 160(4):421–433 Guzmán Cabañas JM, de la Torre Aguilar MJ, Tofé Valera IM, et al. Risk factors involved in the need for blood transfusion in very low birth weight newborns treated with erythropoietin [in Spanish]. An Pediatr (Barc) 2010;73(6):340–346 Singh R, Visintainer PF, Frantz ID III, et al. Association of necrotizing enterocolitis with anemia and packed red blood cell transfusions in preterm infants. J Perinatol 2011;31(3):176–182 Elabiad MT, Harsono M, Talati AJ, Dhanireddy R. Effect of birth weight on the association between necrotising enterocolitis and red blood cell transfusions in
Surgical Findings in Transfusion-Associated Necrotizing Enterocolitis Rosa Fonseca1
Lucía Mangas1
1 Department of Pediatric Surgery, Hospital Universitario y Politecnico
La Fe, Valencia, Spain Eur J Pediatr Surg
Abstract
Keywords
► necrotizing enterocolitis ► blood transfusion ► surgery ► patient acuity
Address for correspondence Miguel Couselo, MD, Department of Pediatric Surgery, Hospital Universitario y Politecnico La Fe. Av. Fernando Abril Martorell 106, 46026, Valencia, Spain (e-mail: [email protected]).
Introduction The extent of intestinal damage in transfusion-associated necrotizing enterocolitis (TNEC) has been scarcely studied. The aim of this investigation was to study surgical findings in TNEC and determine their severity considering the extent of the disease and risk of bowel perforation. Materials and Methods Neonates who required surgical treatment for necrotizing enterocolitis (NEC) were studied retrospectively. Patients who developed NEC within 48 hours after a red blood cell transfusion (RBCT) formed group TR48 and patients who did not receive a RBCT 48 hours before the diagnosis of NEC became group CN (conventional NEC). Both groups were compared: main outcomes were the extent of the disease (isolated, multifocal, or panintestinal), the existence of perforated NEC, and mortality. Categorical variables were analyzed with the chi-square test and continuous variables with the Mann–Whitney U-test. The relationship between RBCTs 48 hours before the diagnosis and the extent of intestinal disease was evaluated by ordinal logistic regression. Results Forty-seven patients were included in the study: 16 patients in TR48 and 31 in CN. The odds ratio of multifocal or panintestinal NEC for patients in TR48 was 0.5 (95% CI: 0.148–1.68). Neonates in TR48 had a relative risk (RR) of perforated NEC of 1.2 (95% CI: 0.76–1.85). The RR of death was 1.55 (95% CI: 0.76–3.14) in group TR48. Conclusion No differences in surgical findings between TR48 and CN could be demonstrated in this investigation; therefore, the hypothesis that intestinal damage might be more severe in TNEC was not confirmed.
Introduction The association between red blood cell transfusions (RBCTs) and necrotizing enterocolitis (NEC) was first reported by McGrady in a cluster of NEC cases in 1987.1 Afterwards, several studies proposed RBCTs as a risk factor for the development of NEC in premature neonates.2–4 Results from a recent meta-analysis based on published retrospective works supported this relationship.5 RBCTs in premature neonates have been associated with different comorbidities, such as retinopathy of prematurity,
received January 27, 2015 accepted after revision March 30, 2015
Juan José Vila1
intraventricular hemorrhage, or NEC.6,7 Oxidative and immunologic mechanisms have been proposed to explain the chain of events between the transfusion and those complications.6,8 The term TRAGI (transfusion-related acute gastrointestinal injury) was created to describe the development of intestinal damage because of RBCTs.4 This expression is analogous to TRALI (transfusion-related acute lung injury), a well-defined entity which causes noncardiogenic pulmonary edema within 6 hours after a blood transfusion.9,10 The pathogenesis of TRAGI is usually explained using the “two hit hypothesis”: in the first hit, vulnerable patients such as premature neonates
© Georg Thieme Verlag KG Stuttgart · New York
DOI http://dx.doi.org/ 10.1055/s-0035-1552570. ISSN 0939-7248.
Downloaded by: Rutgers University. Copyrighted material.
Miguel Couselo1
Couselo et al.
would be exposed to several factors which could activate endothelial cells in the intestine, such as early exposure to antigens in feedings, hypoxemia because of lung disease or infections; in the second hit, the antigens from the donor’s blood would provoke an immunologic response from the previously activated cells. This response would be amplified and cause damage in the mucosal barrier leading to NEC. 11 Transfusion-associated necrotizing enterocolitis (TNEC) is commonly defined as an episode of NEC which occurs within 48 hours after a RBCT. The severity of TNEC has not been clearly determined. On the one hand, according to some investigations TNEC could be a particular type of the disease characterized by an aggressive course and poorer outcomes.2,12,13 On the other hand, there might be no differences in clinical severity of TNEC once the disease is established.4 Nevertheless, to our knowledge, the extent and type of bowel involvement in these patients has not been studied yet. Given the importance of the length of bowel injuries in the prognosis of NEC, assessing both features could help to elucidate if TNEC is really a more severe or fulminant disease which would need a careful and thorough follow-up once the symptoms appear.
Materials and Methods A retrospective investigation of patients diagnosed with NEC between 2002 and 2014 was conducted. The research comprised neonates 34 weeks of gestational age. Cases with congenital heart disease were excluded to avoid possible bias because of hypoxia of this origin. Only neonates with NEC who underwent a laparotomy were included for the analysis. With the intention of excluding other causes of intestinal perforation, the definite diagnosis of NEC was confirmed according to three criteria: clinical data, surgical findings, and histologic reports. Patients with Bell stage I were not studied. Surgical findings were based on the surgeon’s visual inspection of the bowel at the time of surgery. NEC was identified when one or more of these features were found in the absence of obstructive causes: pneumatosis, ischemic injury, gangrene, or perforation. Finally, the histologic study was used to rule isolated intestinal perforations out of the investigation: NEC diagnosis was accepted if there was intense mucosal injury with coagulative or hemorrhagic necrosis. Two groups were considered for this research: TR48 was formed by those patients who had received a RBCT 48 hours before the diagnosis of NEC; patients with NEC who had not been treated with a RBCT 48 hours before the diagnosis became a part of group CN (conventional NEC). The first moment in which a member of the neonatal intensive care unit (NICU) or the neonatology unit evaluated a neonate because of symptoms which corresponded with NEC was considered the time of the diagnosis. RBCTs were administered according to hematocrit levels and clinical status of patients following the criteria of the responsible staff member from the NICU or the neonatology unit. Packed red blood cells were obtained and processed European Journal of Pediatric Surgery
following our institution Blood Bank protocol. This protocol includes irradiation, leukoreduction, preservation, and storage with SAG-mannitol at a temperature between 1 and 5°C. The main outcomes of this study were the features of bowel injuries because of NEC and mortality 90 days after the operation. The type and extent of bowel injuries were registered to evaluate the intestinal damage. The type of bowel injury was divided into the following categories: perforation (if any segment with complete disruption of the bowel wall or feces were found in the peritoneum), necrosis (when gangrene but not perforation was found), and pneumatosis (existence of air bubbles into the intestine wall). The extent of NEC was recorded as an ordinal variable with the following categories: focal NEC (isolated segment of less than 25% of intestinal length), multifocal NEC (two or more intestinal segments involving less than 50% of bowel length), and panintestinal NEC (majority of small and large bowel involved). Other variables recorded for each patient were birth weight, gestational age, 1st and 5th minute Apgar score, age when the symptoms of NEC appeared, hematocrit levels, treatments received before the diagnosis (not only in the previous 48 hours but from the date of admission until the diagnosis of NEC), and surgical treatment. Categorical variables were compared using the chi-square test or the Fisher exact test; relative risks (RR) of bowel perforation and mortality were obtained. The Mann–Whitney U-test was selected for continuous variables. Ordinal logistic regression (Polytomous Universal Model) was used to compare the extent of the disease: it provided a single estimative odds ratio (OR) for all the categories. This OR was calculated by exponentiation of the β coefficient. The statistical analysis was performed using the Statistical Package for Social Sciences (SPSS 17.0).
Results Forty-seven patients with gestational age 34 weeks underwent surgery because of NEC and formed the final sample of the study. Group TR48 consisted of 16 prematures (34%) who were treated with a RBCT 48 hours before the diagnosis of NEC, whereas group CN included 31 patients who did not receive a RBCT 48 hours before the onset of NEC symptoms (►Table 1). There were differences between both groups in gestational age, birth weight, Apgar scores (neonates from TR48 were smaller and with lower Apgar scores), and age at the diagnosis of NEC (patients from TR48 were older). Considering the time from birth to diagnosis, group TR48 was also different in the treatments administered before the diagnosis of NEC: these neonates received a higher number of RBCTs, more ibuprofen and ventilation support. Three patients in group CN and one patient in group TR48 had been operated on before the development of NEC for patent ductus arteriosus (PDA); another patient underwent surgery for an isolated intestinal perforation 3 weeks before the onset of NEC in group CN (a primary intestinal anastomosis was performed in that surgery).
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Surgical Findings in TNEC
Surgical Findings in TNEC
Couselo et al.
Table 1 Demographic and clinical characteristics of the sample TR48 (n ¼ 16)
p-Value
Gestational age (wk)
28 (26–30)
26 (24.5–27.5)
0.018
Birth weight (g)
995 (790–1250)
717 (617.5–850)
0.008
Age at the diagnosis of NEC (d)
9 (7.25–10.75)
13 (10–22)
0.024
1st min Apgar
8 (5–9)
4.5 (3–6)
0.02
5th min Apgar
9 (8–10)
7 (6.25–8)
0.003
Hematocrit after birth
44.3 (38.8–51)
44.2 (40.3–48.6)
0.97
Number of RBCTs before the diagnosis of NEC
1 (0–3)
2 (1.25–3.75)
0.042
Volume of RBCTs before the diagnosis of NEC (mL)
15 (0–29)
20 (13.5–37)
0.289
Hematocrit at the diagnosis of NEC
37.8 (30.6–41.8)
38.4 (35.2–40.3)
0.611
Gender (male)
18 (58.1%)
11 (68.8%)
0.54
Formula feeding
12 (38.7%)
5 (31.3%)
0.61
PDA
15 (48.4%)
13 (81.3%)
0.06
Ibuprofen
13 (41.9%)
12 (75%)
0.03
IVH grade 3
2 (6.5%)
2 (12.5%)
0.6
Ventilation support before the diagnosis of NEC
21 (70%)
15 (93.8%)
0.046
Vasopressor drugs before the diagnosis of NEC
12 (38.7%)
9 (56.3%)
0.25
Abbreviations: IVH, intraventricular hemorrhage; NEC, necrotizing enterocolitis; PDA, patent ductus arteriosus; RBCT, red blood cell transfusion. Note: Continuous variables are described by median, P25, and P75. Categorical variables are described by number of cases and percentage.
Data about RBCTs in the 48 hours before the diagnosis of NEC are presented in ►Table 2. Indications for surgical treatment are summarized in ►Table 3. A laparotomy was performed in all cases. Surgical findings are described in ►Table 4. The most frequent site of the disease was the small bowel in both groups and in a majority of the patients NEC was located in the ileum. Perforated NEC was found in 11 neonates who had been transfused 48 hours before the diagnosis (68.7%) and in 18 who had not received a transfusion in that period of time (58.1%). Therefore, the risk to develop perforated NEC in group TR48 was higher but nonsignificant (RR ¼ 1.2; 95% CI: 0.76–1.85; p ¼ 0.48). The overall probability of multifocal or panintestinal NEC was calculated using an ordinal logistic regression: the OR of developing advanced disease (multifocal or panintestinal) was 0.5 for patients in TR48 compared with those in CN, although this result was nonsignificant (95% CI: 0.148–1.68;
p ¼ 0.26). Cumulative ORs for each category of intestinal injury are showed in ►Table 5. The mortality rate after surgery in the whole sample was 38.3%. Eight deaths occurred in group TR48 (50%) and 10 deaths occurred in group CN (32.3%); the crude RR of death in TR48 was not statistically significant (RR ¼ 1.55; 95% CI: 0.76–3.14; p ¼ 0.24).
Discussion NEC usually appears in premature neonates, especially in those with very low birth weights.14 Similarly, these patients often need multiple RBCTs because of anemia of prematurity, hemorrhage, or frequent phlebotomies.15,16 According to other works, it is generally accepted that premature neonates with TNEC have lower gestational ages, lower birth weights, and a late age of presentation (approximately 3 or 4 weeks after birth).4,11,12,17–19 The first statements were confirmed in the present research; on the
Table 2 Transfusions administered in the interval of time of 48 hours before the diagnosis TR48 (n ¼ 16) Hematocrit before the transfusion
34.5 (31.3–38.1)
Volume of RBCT (mL)
10 (8.5–12.5)
Enteral feeding during the transfusion (%)
7 (43.7%)
Time elapsed from the end of the transfusion to the diagnosis of NEC (h)
34 (10.5–42)
Abbreviation: NEC, necrotizing enterocolitis; RBCT, red blood cell transfusion. Note: Continuous variables are described by median, P25, and P75. Categorical variables are described by number of cases and percentage. European Journal of Pediatric Surgery
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CN (n ¼ 31)
Couselo et al.
Table 3 Indications for surgical treatment of NEC CN (n ¼ 31)
TR48 (n ¼ 16)
Pneumoperitoneum (X-ray)
13 (41.9%)
7 (43.8%)
Fixed bowel loop (X-ray)
5 (16.1%)
3 (18.8%)
Gasless abdomen (X-ray)
5 (16.1%)
4 (25%)
Clinical impairment
8 (25.9%)
2 (12.4%)
Abbreviations: NEC, necrotizing enterocolitis.
contrary, the age at diagnosis was lower in the patients of this sample: 13 days in TR48. This investigation only included neonates who underwent surgical treatment for NEC: their age of presentation was similar to data published by Najaf (14 days at presentation of symptoms) and higher than the result given by Zhang (5.24 days at admission because of NEC) who performed studies which considered exclusive cases of NEC which received surgical therapy.20,21 Given that premature neonates with lower gestational ages and weights are prone to present multiples comorbidities, those cases with TNEC could be expected to develop severe illness before the onset of NEC.22,23 Patients in TR48 received more RBCTs, ibuprofen and respiratory support before the diagnosis: these facts reflect increased intensive care needs in this group. Although Mally reported a series of six healthy, stable neonates developing a fulminant form of NEC after receiving a RBCT, most works indicate that patients with TNEC are usually in worse clinical conditions before the onset of NEC.3,4,12,18 Thus, an accurate adjustment for clinical variables related to common comorbidities of low-birth-weight neonates is mandatory when investigations about TNEC show poorer outcomes in these patients. This adjustment was not performed in this work because there were no differences in major outcomes between the neonates classified as TNEC and those from group CN.
The percentage of patients with TNEC who require surgical treatment has not been clearly established.3,13 However, the main purpose of this investigation was not to determine the risk of surgery in TNEC but to study the surgical findings of neonates who developed NEC immediately ( 48 hours) after an RBCT. The most common finding in the whole sample of patients (TR48 and CN) was NEC with bowel perforation, which appeared in 61.7% of the neonates. This percentage is comparable to the 56% published previously by Najaf.20 Scarce data are available about the precise condition of bowel in TNEC; thus, it is only possible to infer the prevalence of perforated bowel in TNEC using markers of perforation, such as pneumoperitoneum, which is considered to be a very specific indicator of bowel disruption although it lacks sensitivity.24 El-Dib found a significant higher incidence of pneumoperitoneum in TNEC compared with conventional NEC (50 vs. 9.1%) although Josephson did not obtain statistical differences (40% in TNEC vs. 22%).3,25 In the present research, neonates in group TR48 had a higher risk of perforation compared with group CN. This fact could be taken as an indirect sign against the statement that clinical evolution of TNEC is characterized by a fulminant course.2,12,13 Focal NEC was found in more than half of the cases of both TR48 and CN. Multifocal disease was more frequent in TR48 and panintestinal NEC in CN. The result Cumulative OR TR48/ NTR which is exposed in ►Table 5 describes the influence of RBCTs in the extent of bowel injuries. It shows that focal NEC versus multifocal or panintestinal disease was 1.56 times more likely in group TR48 than in group CN. When focal or multifocal NEC versus panintestinal disease was analyzed, the cumulative OR was even higher, reaching 6.14. Logistic ordinal regression provided a single OR estimative for all the categories to summarize these two previous cumulative ORs: the probability of developing multifocal or panintestinal disease was 0.5 in TR48, which was statistically nonsignificant. Therefore, this investigation could not ascertain
Table 4 Surgical findings CN (n ¼ 31)
TR48 (n ¼ 16)
p-Value
18 (58.1%)
11 (68.75%)
0.18
Necrosis without perforation
12 (28.7%)
4 (25%)
0.27
Pneumatosis
1 (3.2%)
1 (6.25%)
0.56
Jejunum
0 (0%)
0 (0%)
–
Ileum
19 (61.3%)
11 (68.75%)
0.61
Colon
0 (0%)
1 (6.25%)
–
Jejunum þ ileum
3 (9.7%)
1 (6.25%)
0.57
Ileum þ colon
5 (16.1%)
2 (12.5%)
1
Jejunum þ ileum þ colon
4 (12.9%)
1 (6.25%)
0.32
Focal
16 (51.6%)
10 (62.5%)
–
Multifocal
6 (19.4%)
5 (31.25%)
Panintestinal
9 (29%)
1 (6.25%)
Findings Type of injury
Location
Extent of the disease
European Journal of Pediatric Surgery
Perforated bowel
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Surgical Findings in TNEC
Surgical Findings in TNEC
Couselo et al.
Table 5 Extent of bowel injuries: cumulative odds ratio Cumulative odds ratio in CN
Cumulative odds ratio in TR48
Cumulative odds ratio TR48/CN
Focal/multifocal or panintestinal
1.07
1.67
1.67/1.07 ¼ 1.56
Focal or Multifocal/panintestinal
2.44
15
15/2.44 ¼ 6.14
support the hypothesis that TNEC could be more severe regarding surgical findings.
Conflict of Interest The authors declare no conflict of interest.
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Conclusion No differences in the type and extent of bowel injuries could be demonstrated when TNEC and NEC unrelated to RBCTs were compared. The results of this investigation do not
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outbreak of necrotizing enterocolitis. Association with transfusions of packed red blood cells. Am J Epidemiol 1987;126(6): 1165–1172 Christensen RD, Lambert DK, Henry E, et al. Is “transfusionassociated necrotizing enterocolitis” an authentic pathogenic entity? Transfusion 2010;50(5):1106–1112 Josephson CD, Wesolowski A, Bao G, et al. Do red cell transfusions increase the risk of necrotizing enterocolitis in premature infants? J Pediatr 2010;157(6):972–978.e1, 3 Blau J, Calo JM, Dozor D, Sutton M, Alpan G, La Gamma EF. Transfusion-related acute gut injury: necrotizing enterocolitis in very low birth weight neonates after packed red blood cell transfusion. J Pediatr 2011;158(3):403–409 Mohamed A, Shah PS. Transfusion associated necrotizing enterocolitis: a meta-analysis of observational data. Pediatrics 2012; 129(3):529–540 Del Vecchio A, Henry E, D’Amato G, et al. Instituting a program to reduce the erythrocyte transfusion rate was accompanied by reductions in the incidence of bronchopulmonary dysplasia, retinopathy of prematurity and necrotizing enterocolitis. J Matern Fetal Neonatal Med 2013;26(Suppl 2):77–79 Christensen RD. Associations between “early” red blood cell transfusion and severe intraventricular hemorrhage, and between “late” red blood cell transfusion and necrotizing enterocolitis. Semin Perinatol 2012;36(4):283–289 Wang-Rodriguez J, Fry E, Fiebig E, et al. Immune response to blood transfusion in very-low-birthweight infants. Transfusion 2000; 40(1):25–34 Benson AB, Austin GL, Berg M, et al. Transfusion-related acute lung injury in ICU patients admitted with gastrointestinal bleeding. Intensive Care Med 2010;36(10):1710–1717 Rashid N, Al-Sufayan F, Seshia MMK, Baier RJ. Post transfusion lung injury in the neonatal population. J Perinatol 2013;33(4): 292–296 La Gamma EF, Blau J. Transfusion-related acute gut injury: feeding, flora, flow, and barrier defense. Semin Perinatol 2012;36(4): 294–305 Mally P, Golombek SG, Mishra R, et al. Association of necrotizing enterocolitis with elective packed red blood cell transfusions in stable, growing, premature neonates. Am J Perinatol 2006;23(8): 451–458 Christensen RD, Wiedmeier SE, Baer VL, et al. Antecedents of Bell stage III necrotizing enterocolitis. J Perinatol 2010;30(1): 54–57 Hall NJ, Curry J, Drake DP, Spitz L, Kiely EM, Pierro A. Resection and primary anastomosis is a valid surgical option for infants with necrotizing enterocolitis who weigh less than 1000 g. Arch Surg 2005;140(12):1149–1151 European Journal of Pediatric Surgery
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differences between TR48 and CN when bowel injuries caused by NEC were evaluated. Overall mortality in this work was 38.3%; past reports about surgical treatment of NEC by laparotomy estimated that mortality could vary from 25 to 48%.2,26–29 When TR48 and CN were compared, neonates who had received a RBCT 2 days before the onset of NEC had a higher RR of death, which was statistically nonsignificant. A previous work published in 2010 by Christensen with neonates who underwent surgery found that mortality in neonates with NEC unrelated to transfusion was 28% and mortality in neonates with NEC following transfusion was 40%; likewise, these data showed no statistically significant differences. Panintestinal and multifocal disease are usually stated as major determinants of mortality in NEC.29–31 The analysis of mortality in this research was consistent with the results related to the length of affected bowel considering that differences between TR48 and NTR were not demonstrated. However, despite the fact that the RR for mortality was > 1 in TR48, the OR for advanced NEC was < 1 in TR48. A possible interpretation of this paradox could be that neonates in group TR48 were more immature and unstable: they had lower weight and gestational age, and needed more ventilation support. These features might have contributed to decreased survival rates.32 A common limitation in TNEC retrospective studies is that mild or subtle nondigestive symptoms might not be adequately recorded as part of the clinical onset of NEC; this would lead to inaccurate intervals between RBCTs and NEC. Another limitation in this investigation was the small sample size, which is a frequent characteristic in clinical studies about NEC; it might have caused that differences between the two groups (TR48 and CN) were not found. Finally, there were obvious subjective criteria in the assessment of the length of bowel affected by NEC. Although in some cases the injuries were measured and registered in centimeters, there were patients in whom this task was difficult because of multifocal disease or diffuse limits between healthy and slightly ischemic intestine. In an attempt to minimize this limitation, the extent NEC was considered as focal, multifocal, and panintestinal; however, this classification provided less precise information than numeric data.33,34 Consequently, the analysis of the extent of the disease was performed using ordinal logistic regression and cumulative ORs.
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15 Venkatesh V, Khan R, Curley A, New H, Stanworth S. How we
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decide when a neonate needs a transfusion. Br J Haematol 2013; 160(4):421–433 Guzmán Cabañas JM, de la Torre Aguilar MJ, Tofé Valera IM, et al. Risk factors involved in the need for blood transfusion in very low birth weight newborns treated with erythropoietin [in Spanish]. An Pediatr (Barc) 2010;73(6):340–346 Singh R, Visintainer PF, Frantz ID III, et al. Association of necrotizing enterocolitis with anemia and packed red blood cell transfusions in preterm infants. J Perinatol 2011;31(3):176–182 Elabiad MT, Harsono M, Talati AJ, Dhanireddy R. Effect of birth weight on the association between necrotising enterocolitis and red blood cell transfusions in
