Inadequate intravenous feeding in sick neonates: a retrospective study

Cbnr~o/Nutnrion (1994) 13: 161-165 0 Longman Group Ltd 1994

Inadequate intravenous feeding in sick neonates: a retrospective study A. J. R. DEPRETTERE”,

K. J. VAN ACKER*,

Department of Paediatrics, Division *Endocrinology, Division of Clinical Antwerp, Belgium (Correspondence

P. J. VAN REEMPTS

and I. DE LEEUW*

of *Gastroenterology and +Neonatology, and Department of Nutrition, University Hospital, Antwerp, Wilrijkstraat IO, B-2650 and reprint requests to AJRDI.

ABSTRACT-It is a common experience that during intravenous feeding (IVF) in neonates the administered amounts do not always meet the recommendations. In an attempt to quantify these deficits and to determine the causes we studied the data of 2 comparable groups of neonates admitted to a neonatal intensive care unit (NICU). In Group 1 (N = 107; gestational age 25-42 weeks; birth weight 690-5920 g) the minimum recommended intake of energy (70 kCal/kg/d) and of aminoacids (2.5g/kg/d) was not met in 17% and in 71% respectively. The main causes of inadequate intake were believed to be the nearly exclusive use of peripheral venous access, and the restriction in glucose and/or lipid administration because of extreme prematurity and/or severe illness. In Group 2 (N = 99; gestational age 24-42 weeks; birth weight 670-4300 g), where these causes were corrected, 11% and 54% of the patients still received an insufficient amount of energy and amino acids respectively. It can be concluded that in the daily practice in a NICU, even in optimal conditions and following the recent recommendations for IVF, a considerable proportion of preterm neonates do not receive the minimal recommended amount of energy and aminoacids.

Introduction Intravenous feeding (IVF) is a well established technique in neonatology (1). It is used exclusively or in combination with enteral feeding to provide the necessary energy and nutrients. Sufficient data are now available on the nutritional requirements in this age group (l-5), but commonly in daily practice the administered amounts do not meet these recommendations. No systemic studies have been undertaken to assess the extent and the causes of the deficits. In the present study we have tried to collect such data in 2 comparable groups of sick neonates in a neonatal intensive care unit (NICU). In Group 1 the amounts of fluid and nutrients that were actually administered, were evaluated and the possible causes of the deficits investigated. The same data were then collected in Group 2 after correction of these causes.

Patients and methods The first group (Group 1) consisted of 107 neonates, admitted to our NICU between January 1986 and December 1988 and treated with IVF because of pre-

maturity or severe illness possibly associated with prematurity (Table 1). The definitions of intravenous feeding used in this study are represented in Table 2. Glucose and/or electrolyte solutions given separately from IVF were considered as part of the IVF only if

Table 1 study

Clinical data on the patients during the 2 periods of

Patients (n) Gestational age (weeks Birth weight(g) Episodes (n) Diagnosis: (**) Asphyxia (n) Pulmonary disease Cardiovasc. disease G-I tract disease Septicemia Intracranial hemorrhage Renal failure

)

Group 1

Group 2

107 33 * 4(*) (25-42)(O) 1745 f 792 (690-5920) 107

99 31.9+4 (2442) 1640 f 842 (67&4300) 110

19 85 46 57 45 20 5

P

N.S. N.S.

14 87 39 33 21 7 1

(*) mean f SD: (“) range; (**) some patients are placed in more than one diagnostic category.

16'2lNADEQUATElNTRAVENOUSFEEDING1NSICKNEONATES Table 2

Definitions used in the study

Intravenous Feeding (IVF): the IV administration

of solutions containing aminoacids, glucose, electrolytes, vitamins, trace elements and mostly also lipids.

Total Parenteral Nutrition (TPN): the exclusive administration of IVF Enteral Nutrition (EN): the nutrition administered route.

via enteral

Partial Parenteral Nutrition (PPN): the IVF given in combination with EN. Episode: the period during which IVF is administered in one of the following regimens: TPN, PPN + EN, TPN immediately followed by PPN + EN. Total Feeding (TF): the IVF and EN administered episode.

during one

administered simultaneously with the latter. For TPN or PPN a standard solution was used consisting of fixed amounts of electrolytes, vitamins and trace elements which were mixed under laminar airflow with varying amounts of amino acids and glucose according to the patient’s needs. A 10% or 20% lipid emulsion was prepared and administered separately (Table 3). A peripheral venous access was used in all patients; only in 18 (17%) was it combined with a central venous catheter. The fluid administration was kept at 150 ml/kg BW/d except when the clinical condition dictated increased or restricted fluid amounts. The composition of the standard solution was altered only when significant fluid restriction or increase was indicated or when important electrolyte disturbances were observed in the patient. The prescribed amounts of macronutrients and micronutrients were those recommended in the literature at that time (1, 4, 5). The minimum intended amount of energy, allowing growth, was 70 kCal/kg BW/d (4). although the aim was to give more than 90 kCal/kg BW/d. The intended amino acid intake was 2.5 g/kg BW/d (4, 5). The amount of lipids aimed at was 40% of the non-protein calories with a maxiTable 3

Composition

Amino acid solution Lipid emulsion Electrolyte solution (mmol/dl): Na K Cl Ca P Mg

of the IVF used in the studies. Group 1

Group 2

Vamin-glucose Intralipid 10%/20%

Prim&e 10% Intralipid 20%

3 1 2.5-3.5 1.0 1.0 0.7

3 1 2.5-3.5 1.3 1.3 0.3

mum lipid intake of 4 g/kg BW/d in neonates with birthweight above 1250 g, and 2.0-2.5 g/kg BW/d in neonates with birthweight below 1250 g (6-8). In all patients the biometrical, biochemical and haematological controls that are customary in IVF, were performed at fixed intervals (5). The IV lipid administration was monitored by serum triglyceride levels which were kept at or below 150 mg/dl (9). Data on nitrogen excretion or on energy expenditure were not available. The fluid volume, the energy content and the amount of nutrients in the IVF, in the EN and in the glucose and/or electrolyte solutions administered concomitantly with the IVF, were carefully registered. The calories provided by TPN or PPN were calculated as non-protein calories while for the EN the calories provided by protein were also taken into account. The second group (Group 2) consisted of 99 neonates, admitted to the same NICU between January 1990 and June 1992. They represented 110 episodes of IVF: 11 patients with relapsing or continuing illness received IVF during 2 different episodes interrupted by an episode of exclusive EN. The patients were not statistically different from Group 1 with regard to number, gestational age, birth weight and pathology (Table 1). The indications for IVF and the definitions used were the same as in Group 1. In Group 2 central venous catheters were used in all patients, in 6 I % of them for the whole duration of TF. In none of the patients was an exclusively peripheral venous access used. A special protocol for prevention of catheter related infections was designed. Further changes of policy in Group 2 consisted of the use of an amino acid solution that was more adapted to the needs of premature neonates (IO), the exclusive use of a 20% lipid emulsion (1 l), and an increase of the Ca and P concentration and a decrease of the Mg concentration in the standard solution (3, 12) (Table 3). Furthermore, the intended amino acid intake was increased to up to 3.5 g/kg BW/d, as advised in some studies (4), the administration of IV lipids was less restrictive and a more liberal, although not systematic, use of insulin in the event of glucose intolerance was advocated. The same biometrical, haematological and biochemical controls were performed as in Group 1. The same data as in Group 1 were collected, using the same definitions of energy. For statistical comparison between the two groups the Mann-Whitney test for non-paired data was used.

Results

In Group 1, TPN followed by PPN + EN was given in 91 neonates, exclusive TPN in 1, and exclusive PPN +

CLINICALNUTRITION

EN in 15. The mean duration of TF was 27 * 20 (range: 7-108) days, for TPN it was 13.4 + 11.4 (range: l-51), and for PPN + EN it was 15.8 + 12.3 (range: l-69). The amounts of fluid, energy, amino acids, lipids and carbohydrates which have actually been administered with the different regimens are presented in the Table 4. The mean amount of fluid administered approached the recommended volume. However, as shown by the range, important variations occurred. The energy supply during TF was less than 70 kCal/kg BW/d in 18 neonates ( 17%) and reached more than 90 kCal/kg SW/day in 40 (37%). During TPN less than 70 kCal/kg BW/d were given in 56 patients (61%), in 14 (15%) more than 80 kCal/kg BW/d were administered. During PPN + EN, where 58% of the calories were given as PPN and 42% as EN, less than 70 kCal/kg BW/d were given in 11 patients (10%) and more than 90 kCal/kg BW/d in 66 (62%). The amino acid supply during TF was less than 2.5 g/kg BW/d in 76 patients (71%) it was 2.5 g/kg BW/day or more in 3 1 neonates (29%). During TPN less than 2.5 g/kg BW/d of aminoacids were given in 90 patients (98%); 2.5 g/kg BW/day or more in only 2 patients (2%). During PPN + EN less than 2.5 g/kg BW/d of amino acids or protein were given in 44 patients (42%); in 62 (58%) it was 2.5 g or more. Half the amount of nitrogen was given as PPN and half as EN. Although the mean amount of carbohydrate administered was around 15 g/kg BW/d, there was a wide

Table 4

Amounts of fluid, energy and nutrients administered Volume (ml)

TF

TPN

PPN

EN

PPN EN

I II 158.0”’ 118.8 22.4’?’ 22.7 106.0-220.0’3’ 59.4-171.0 P < 0.001 145.8 118.2 25.7 33.2 86.0-228.0 36.4-201.7 P < 0.001 108.0 91.9 24.4 15.2 53.0-210.0 40.9-134.7 56.0 51.5 20.0 16.3 3.&l 10.0 8.9-l 13.5 + 164.0 143.3 22.5 14.3 104.0-224.0 88.8-199.0 P < 0.001

II

82.8 14.5 44.0-120.0

84.8 12.3 52.9-l 13.5 NS

64.7 15.5 16.0-89.0

66.1 19.4 17.7-116.0 NS

53.0 12.6 15.5-89.1 38.8 14.0 1.5-70.0 91.9 16.2 40.0-121.4

61.5 12.6 33.4-88.1 32.7 11.5 2.9-66.6 94.2 12.2 5l.kl25.3 NS

(1): mean; (21: SD: (31: range: I: Group I; II: Group II

range showing that very low amounts were given in individual patients. The mean amount of lipids administered was well below the intended amount and represented only 25% of the non-protein calories in TF and 10% in TPN. During TPN some patients did not receive IV lipids. In Group 2, TPN followed by PPN + EN was given during 100 episodes, exclusive TPN during 2, and exclusive PPN + EN during 8 episodes. The mean duration of TF was 22.2 f 14.8 (range: 7-92) days, for TPN it was 10.5 + 10.7 (range: l-64) and for PPN + EN it was 12.7 f 6.2 (range: 2-37). The amounts of fluid, energy, amino acids, lipids and carbohydrates which were actually administered with the different regimens are presented in the Table 4. The mean fluid administration during TF and TPN. but not during PPN + EN, was below the intended amount and showed a wide variation. The amount of energy given with TF was less than 70 kCal/kg BW/d during 12 episodes (11%) and was more than 90 kCal/kg BW/d during 41 episodes (37%). With TPN less than 70 kCal/kg BW/d were given during 57 episodes (56%), more than 90 kCal/ kg BW/d during 6 episodes (6%). During PPN + EN, where 65% of the calories were given as PPN and 35% as EN, less than 70 kCal/kg BWld were given during 3 episodes (3%) more than 90 kCal/kg BW/d during 74 (69%). During TF the amino acid supply was less than 2.5 g/kg BW/d during 60 episodes (54%), it was 2.5 g/kg BW/d or more during 50 episodes (46%) but in none of the patients the intended amount of 3.5 g/

with the different regimens

Calories (Kcal) I

163

Aminoacids I 2.2 0.4 0.8-3.1

(g) II

1.4 0.4 1.1-3.1 P = 0.01 1.7 1.9 0.5 0.8 0.4-2.7 0.2-3.5 P < 0.01 1.3 1.8 0.4 0.4 0.1-2.3 0.7-2.8 1.2 0.7 0.5 0.3 0.1-2.2 0. I-2.0 2.5 2.6 0.5 0.4 0.3-3.4 1.1-3.5 P < 0.001

Lipids (g) I

Carbohydrates II

2.1 2.7 0.8 0.9 0.2-4.5 0.2-5.2 P
I

(g)

II 15.0 14.3 2.5 2.1 7.5-20.1 9. I-20.4 P < 0.01 14.5 13.9 3.3 3.7 4.0-20.1 4.G23.7 NS 11.1 11.0 2.7 2.4 3.9-17.9 4.3-18.0 4.1 3.4 1.5 I.2 0.2-8.0 0.36.8 15.2 14.3 2.6 2.0 8.5-20.7 9.2-20.3 P < 0.001

164

INADEQUATE INTRAVENOUS FEEDING IN SICK NEONATES

kg BW/day was reached. During TPN less than 2.5 g/ kg BW/d of amino acids were given during 69 episodes (68%), 2.5 g/kg BW/d or more were given during 33 episodes (32%) but in only 1 instance were 3.5 g/kg BW/d given. During PPN + EN, where 70% of the amino acids were given as PPN and 30% as EN, the amount of amino acids/ protein was less than 2.5 g/kg BW/d during 46 episodes (43%), it was 2.5 g/kg BW/d or more during 62 (57%). The mean amount of carbohydrates administered was around 14 g/kg BW/d and again showed a wide range, indicating that very low amounts were given to individual patients. The mean amount of lipids administered was well below the intended amount and represented 32% and 17% of the non-protein calories during TF and TPN respectively. The part of IVF given as transfusion or as infusion to keep an open access or for medication, accounted for 3% of the IV fluid, 8% of the IV calories during TF and 0.2% of the IV calories during TPN.

Discussion Patients in a NICU often do not tolerate enteral feeding. Moreover acute stress situations, which increase the nutritional demands (1, 13), frequently occur. Therefore, if malnutrition and its repercussion on growth and development of different systems is to be avoided, IVF is often necessary. Although theoretically feasible, IVF, even when combined with EN, not always results in the administration of the required amounts of energy and nutrients in these neonates in daily practice. The reasons for these deficits are probably multiple but have, to our knowledge, not been studied systematically. The results in Group 1 showed that with TF the recommended amounts of energy and nitrogen were not reached in 17% and 71% respectively of the patients, while with TPN these figures were 61% and 98%. With PPN + EN, 10% and 42% of the patients failed to receive the intended amounts of calories and nitrogen respectively. It was concluded from these figures that inadequate nutrition occurred during IVF, and predominantly during TPN. A main cause of this inadequate nutrition was believed to be our reluctance to use central venous catheters, dictated by fear of complications (1). Nutritional deficits due to the exclusive use of peripheral catheters have been described in children (14). The exclusive use of a peripheral venous access makes a sufficient increase of the concentration of nutrients such as glucose or amino acids impossible when fluid restriction is needed. Moreover its use is frequently complicated by

technical problems that cause interruption of the administration (15). However, as this problem was not registered systematically, its impact on the nutritional supply in our patients could not be evaluated. Other possible reasons for giving less than the recommended amounts were glucose and/or lipid intolerance due to prematurity or severe illness (5, 16). We decreased the glucose administration in the presence of hyperglycemia or in situations known to predispose to hyperglycemia such as septicaemia or stress. The use of insulin, still debated at present, was applied with much restraint (16-18). IV lipid administration was diminished or interrupted when serum triglyceride levels exceeded 150 mg/dl, in the presence of hyperbilirubinemia or in situations which predispose to hypertriglyceridemia such as postoperative stress or septicaemia. Furthermore we surmised that the administration of fluids with less nutritive value such as transfusions and infusions to keep access lines open or administer medication, added to the deficits, although this was not quantified. To evaluate whether correction of these factors would result in a nutritional supply in accordance with the general recommendations, we adapted our policy on IVF in Group 2. In this group the amount of fluid given was significantly lower than in Group 1, due to a strict fluid restriction policy in small preterm neonates with cardiorespiratory problems. The amount of calories/kg BW/d given in Group 2 was not statistically different from Group 1. The recommended amount of energy was still not reached during 1 l%, 56% and 3% of the episodes with TF, TPN and PPN + EN respectively. There was a slight but significant increase of the amount of amino acids (g/kg BW/d) given during TF and TPN in Group 2 as compared to Group 1. However, the recommended amounts of nitrogen were not reached during 54%, 68% and 43% of the episodes with TF, TPN and PPN + EN respectively. The amount of administered lipids was significantly higher in Group 2 than in Group 1. The amount of carbohydrates was slightly lower for the TF where it reached the limit of significance, but not for the TPN. Again it could be concluded that during IVF, and predominantly during TPN, nutrition was inadequate, although to a lesser extent than in Group 1. Thus, adaptation of our feeding policy in Group 2 did not result in the expected amelioration of energy and nutrient intake, although significantly more amino acids and lipids were given during TF. There are several possible explanations for this lack of effect. A first explanation is that some of the forementioned factors were not adequately controlled. This could, for example, be true for the glucose intolerance, which was treated with insulin in only a few

CLINICAL NUTRITION

cases mainly due to our fear of sudden changes in plasma osmolality. Also the fear of adverse effects of IV lipids was probably exaggerated. Although such adverse effects have been reported (8, 19), their occurrence is not supported by systematic studies. Consequently our upper limit of serum triglycerides at 150 mg/dl was probably too low. Another explanation is that the real cause of insufficient nutrition was not identified in a number of patients from Group 1. Finally it may be that in some of these patients it is impossible to reach the recommended amounts. It is, indeed, well known that in critically ill infants and in infants with extremely low birth-weight glucose homeostasis is unstable and lipid tolerance is limited (5, 16): these metabolic disturbances counterbalance the advantage of central venous catheters with its possibility to administer concentrated solutions. Furthermore, as in both groups the amount of energy and nutrients is higher with PPN + EN than with TPN, the delay in starting enteral feeding certainly added to the inadequate nutrition. However, poor tolerance of enteral feeding is frequently observed in this age group and there is a substantial risk of necrotizing enterocolitis. Therefore adequate feeding remains a major problem in this category of neonates. The impact of infusion of fluid with little or no nutritive value, which we believed to be important after the first part of the study, proved to be neglegible. Catheter related problems were not responsible for interruptions of the IVF. One could object that the 2 groups in our study are not totally comparable as the difference in time implies a difference in experience and skills of the medical and the nursing staff, and also that one part of the study was retrospective while the other was prospective. Even when allowing for this bias, the results in Group 2 clearly show that IVF was insufficient. It can be concluded that even in optimal conditions and following the recent recommendations for IVF, critically ill preterm neonates often do not receive sufficient nutritional support.

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Submission

date: 7 June 1993; Accepfed affer revision: 17 November

19.

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165

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