Abstract
Background:
To determine effectiveness of a nurse-led, volume-based feeding protocol in our pediatric intensive care unit (PICU), we evaluated patients’ nutrition adequacy pre- and post-protocol implementation.
Methods:
We conducted an observational study of patients admitted for more than three days in the PICU during pre- and post-feeding protocol periods. We recorded energy and protein intake and feed interruptions in patients started on enteral nutrition over the first seven days of admission. We excluded patients with septic shock requiring more than two inotropes, post-cardiac and post-gastrointestinal surgeries. To determine nutrition adequacy, actual energy and protein intakes were compared with calculated requirements, expressed as percentages.
Results:
We had a total of 40 patients (20 in the pre- and post-protocol groups, respectively) with median age of 9.4 (interquartile range (IQR) 2.8, 57) months. Median time to feed initiation was similar between groups (20.0 (IQR 17.0, 37.5) vs. 21.5 (IQR 10.5, 27.0) hours, p = 0.516). There was no difference in median energy (55 (IQR 12, 102) vs. 59 (IQR 25, 85) %, p = 0.645) and protein intake (53 (IQR 16, 124) vs. 73 (IQR 22, 137) %, p = 0.069) over the seven-day period between groups; the proportion of patients meeting their energy (10 vs. 35%, p = 0.127) and protein goal (15 vs. 30%, p = 0.451) by day three also did not differ significantly pre- and post-protocol implementation. The most common reasons for feed interruption were intubation/extubation and radiological procedures.
Conclusion:
Our current feeding protocol did not improve nutrient adequacy. The effectiveness of a more aggressive protocol in units where enteral nutrition is initiated within 24 hours should be investigated.
Introduction
Malnutrition, common in critically ill pediatric patients, increases morbidity and mortality risk.1–3 Malnutrition is associated with physiological instability due to altered metabolism of certain substrates, elevation of basal metabolic rate and protein catabolism, and reduced nutrient delivery.1,3 Early initiation and optimal feed provision has been shown to improve clinical outcomes in critically ill patients.1,2,4–6 Enteral nutrition (EN) is the preferred mode of feeding in patients with a functional gut and compromised oral intake.4,7 In addition to being more physiological and economical compared to parenteral nutrition, EN also stimulates and protects the integrity of the gut and the immune system leading to reduction in sepsis and multi-organ failure.1,3,6,8,9 Despite the high prevalence of malnutrition and the well documented benefits of early EN, delayed and non-standardisation of feeding practices in the pediatric intensive care unit (PICU) remains common.4,10
The use of a clear and concise evidence-based protocol has the advantage of reducing practice variations and ensuring standardisation of care leading to improvement of patient’s care.4,11 However, there are only limited studies examining the utility of feeding protocols in PICUs.4,12,13 A recent systematic review demonstrated that there is a low level of evidence that protocol-driven EN in critically ill children improves clinical outcomes, time to initiate and achieves goal feeds. 14 This provided an impetus for us to examine the effectiveness of a nurse-led feeding protocol in our PICU looking at nutritional goals pre- and post-feeding protocol. The primary aim of this study is to determine whether the implementation of a feeding protocol in the PICU improves EN adequacy and timeliness to initiation. As interruption of EN is common, largely avoidable, and results in deprivation of EN,15,16 we also intend to examine the common reasons for feed interruption in the PICU.
Materials and methods
Study design
We conducted an observational before and after study in the PICU at KK Women’s and Children’s Hospital, Singapore. Our PICU is a 16-bed unit that admits medical, surgical, and cardiothoracic patients. The study was approved by our hospital’s institutional review board without the need for patients’ informed consent.
Prior to the introduction of the feeding protocol in the PICU, feed initiation and advancement was dependent on orders given by attending physicians. Hence, there was no standardised practice as to when to start feeding and how much to feed to patients. Starting in March 2013, a nurse-led feeding protocol was initiated to provide standardised care with clear guidelines on the initiation and progression of EN for critically ill pediatric patients. The protocol was developed by a multidisciplinary team consisting of PICU physicians, nursing staff and dietitians. With the protocol, nurses were responsible for the grading-up of feeds and highlighting to the medical team any problems encountered during feed progression. To ensure early feed initiation, patients on feeding protocol were meant to commence feeding within 24 hours of PICU admission. The feeding protocol was volume-based and increments were stepwise depending on the mode of delivery – either bolus or continuous feeding (see Appendix). Patients were routinely started on bolus feeds; however, in the instances where they experience feed intolerance on bolus or if prior to feed initiation they were assessed to be at risk of feed intolerance, continuous feeding will be initiated. The protocol aimed to achieve target volume by the second day of EN in patients without any fluid restriction, the goal volume set was expected to meet patients’ nutrition adequacy.
The study population consisted of patients admitted to the PICU for at least three consecutive days and started on EN. We excluded the following patients from the feeding protocol: post-cardiac surgery patients, patients with septic shock requiring two or more inotropes and patients with significant gastrointestinal concerns or recent gastrointestinal surgeries. Cardiac surgery patients are often put under strict fluid restriction post-operatively; hence, optimal nutrition may not be achieved via the feeding protocol. Because of potential risk of gut ischemia, patients with septic shock supported with two or more inotropes were excluded from our protocol. Patients with significant gastrointestinal issues may be on parenteral nutrition and/ or be at risk of feed intolerance with rapid feed progression, we therefore chose to exclude this group from the feeding protocol. As the aim was to assess how effective the protocol was in providing adequate nutrition via an enteral route, patients who were on partial or total parenteral nutrition were not included in the study. In the pre-protocol group, 20 patients were recruited from September 2012 to February 2013. Prior to the feeding protocol implementation, in-service education on the use of the protocol was conducted by a dedicated nurse clinician, physician and dietitian. All nursing staff also had to fulfil a competency checklist.
Following the implementation of the feeding protocol in March 2013, we allowed for a two month “wash-in” period for staff to become familiar with the new protocol before the recruitment of eligible patients for the post-protocol period. During this “wash-in” period, educational reminders (pop-up signs) were made available around the PICU, and PICU staff was reminded at daily rounds to use the feeding protocol on all patients meeting the criteria. From May 2013 to February 2014, 20 patients were recruited for the post-protocol group.
Data collection
In both pre- and post-protocol groups, we collected data from electronic records using a standardised data sheet. Patient’s baseline characteristics, PICU length of stay (LOS), hospital LOS, pediatric risk of mortality (PRISM) score, duration of mechanical ventilation, and mortality were collected. We also recorded the time to feed initiation and feeds received for a period of seven consecutive days or till discharged from the PICU, whichever was earlier. Energy and protein requirements were calculated using Schofield equation and dietary reference intakes for age respectively, with stress factor adjusted for. Stress factor is taken into account when calculating requirements as additional energy needs may arise from metabolic and hormonal changes such as inflammation, and cytokine responses in relation to injury, trauma, or disease. Actual energy and protein intakes were compared against calculated requirements, expressed as percentages, to determine nutrition adequacy. We defined nutrition adequacy as meeting more than 85% of energy and protein requirements over the first seven days of PICU admission or discharge, whichever was earlier. This cut-off for optimal nutrition was similar to that defined in a previous pre- and post-protocol study conducted in PICU patients. 12 Cases of EN interruption were categorised into the following broad groups: significant respiratory distress; high gastric residuals; bloody or colored aspirates; endotracheal intubation or extubation; radiological procedures; abdominal distension and vomiting. Feeds that were stopped for any of these reasons were defined as an episode of feed interruption.
Statistical analysis
We summarised continuous demographics variables as medians (with interquartile ranges); binary or categorical data as numbers and percentages. Univariate statistical tests for binary or categorical variables were conducted by the Fischer exact test, while continuous variables were assessed by the Mann–Whitney test. Statistical analysis was performed using Stata 12.1 (College Station, TX) and statistical significance was taken as p values < 0.05 for all tests.
Results
A total of 40 patients were enrolled and their baseline characteristics are summarised in Table 1. The two groups were comparable except for ethnicity (p = 0.043) and admission diagnosis (p = 0.031). The median age of the patients was 9.4 (2.8, 57.0) months. Respiratory indications (n = 23) were the main reasons for admission in both groups. Of the 40 patients, nine were not on mechanical ventilation throughout their stay in the PICU. The median duration of mechanical ventilation was 5.5 (2.0, 8.0) days.
Patient characteristics and clinical outcomes.
Continuous data presented as medians (interquartile ranges) and categorical data as numbers (percentages).
The median time to feed initiation was similar (20.0 (17.0, 37.5) hours pre-protocol vs. 21.5 (10.5, 27.0) hours post-protocol, p = 0.516) (Table 2). There was no difference in feed initiation beyond 48 hours in the post-protocol compared to the pre-protocol group (4 (20%) vs. 1 (5%), p = 0.342). Median caloric intake over the first seven-day period was inadequate and not significantly different in both pre- and post-protocol groups (55 (12, 102) % vs. 59 (25, 85) %, p = 0.645), respectively. There were 4 (20%) and 3 (15%) patients in the pre- and post-protocol groups, respectively, who had their overall caloric intake exceeding 100% of their requirements by day 7. Despite median protein intake being higher at 73 (22, 137) % in the post-protocol group compared to the pre-protocol group at 53 (16, 124) %, this difference did not achieve statistical significance (p = 0.069). Protein intake exceeding 100% of requirements was also noted in 3 (15%) and 4 (20%) patients in the pre- and post-protocol group, respectively. There was no difference in the proportion of patients meeting 85% of their energy (2/20 vs. 7/20, p = 0.127) and protein (3/20 vs. 6/20, p = 0.451) requirements pre- and post-protocol, respectively.
Nutritional outcomes.
Presented as medians (interquartile ranges).
The majority of our patients (33 (83%)) experienced at least one episode of feed interruption (18 and 15 from the pre- and post- protocol group, respectively). A total of 72 episodes of feed interruption were recorded (Table 3). In these 72 episodes, the most common reasons were for endotracheal tube intubation or extubation (22 (31%)) and radiological procedures (21 (29%)). The duration for which feeds were stopped for these common clinical interventions varied widely: feeds were stopped for 6–14 hours for endotracheal tube intubation and 5–18 hours for radiological procedures. Apart from clinical interventions, respiratory distress (12 (17%)) and high gastric residual volume (GRV) (8 (11%)) were other common reasons for feed interruption. The median time for which feeds were held for the top three most common reasons are also reported in Table 3. There were 1 (5%) and 5 (20%) patients in the pre- and post-protocol group, respectively, having to convert from bolus to continuous feeds. All of these patients except for one were converted in view of high GRV.
Reasons for feed interruptions.
Only top three reasons for feed interruptions were reported.
Discussion
EN had been traditionally withheld in critically ill patients until they were clinically more stable. 9 However, there is increasing evidence indicating that early feeding is feasible, well tolerated,4,15,17,18 cost saving, 9 and reduces time to reach caloric goal and protein balance.4,12,17,19–21 Despite no clear evidence indicating the optimal time for EN initiation, it is generally accepted that initiating feeds within 24 to 48 hours would be a reasonable recommendation. 1 In addition, feeds are often delayed due to multiple reasons such as elective procedures, unplanned interventions and perceived feed intolerance. 15 In our study, 88% (n = 35) of our patients still had their feeds initiated within 48 hours of admission with the median time to feed initiation being within 24 hours. This suggests that even prior to protocol implementation our PICU already practiced early feed initiation. In a multicentre cohort study looking at nutritional practices in the PICU, up to 40% of patients from 31 PICUs did not have their feeds initiated within 48 hours of admission. 2 In critically ill adults, feeding protocols had been demonstrated to improve time for feed initiation regardless of whether prior to protocol introduction, feeds were started before or after 24 hours. In the pediatric setting, the evidence for which feeding protocol improve feed initiation is however less robust. More studies are required to show whether feeding protocols will benefit PICUs where feed initiation is started beyond 48 hours.
Nutrition delivery has been shown to improve with the use of a feeding protocol in the PICU in two before and after studies.4,12 Both these studies determined energy requirements based on predictive equations with stress factor taken into account. In a study that included 171 children, a nurse-driven feeding algorithm and a nutrition support team were introduced at the same time, hence the authors were unable to conclude whether the improvement in nutritional delivery in the PICU patients was attributed to the introduction of the feeding algorithm, the nutrition support team, or both. 12 EN according to their feeding algorithm was initiated via continuous feeding. Feeds were started at 25% of target with rates increased by 25% of target every four hours until goal. Although our protocol for continuous feeds also commences feeds at 25% of target, our increment rate at 0.5 mL/kg/h every four hourly was less aggressive compared to the feeding algorithm utilised in the other study.
In another study that included 183 children, patients in the post-feeding protocol group achieved goal nutrition in a much shorter time compared to the pre-protocol group (mean: 18.5 vs. 57.8 hours, p < 0.0001). 4 In this study, the feeding protocol was implemented together with a standardised constipation management regimen which the authors suggest may have reduced gastric intolerance, hence shortening the time to achieve goal feeding. Similarly, it is difficult to identify whether the reduced time to goal feeding was due to the feeding protocol or the standardised bowel regime, or both. The starting rate and advancement schedule of the feeding algorithm was not described for this study.
In contrast to these two studies, our study did not demonstrate an improvement in caloric intake with the introduction of a nurse-led feeding protocol. Our finding was instead similar to recent findings reported by Martinez et al., 16 who examined nine international PICUs that used EN algorithms. Of the 341 patients who received exclusive EN, 32.9% did not achieve optimal nutrition (defined as ⩾66.6% of prescribed energy) by day seven. A possible reason could be attributed to protocols lacking in evidence-based recommendations for EN practices as proposed by the American Society for Parenteral and Enteral Nutrition (ASPEN), as well as European Society for Paediatric Gastroenterology and Hepatology and Nutrition (ESPGHAN). 16 We determined energy and protein requirements using standard equations with stress factor adjusted for. Stress factor was adjusted by the dietician based on patients’ condition during their PICU stay. Patients who were well-nourished, intubated and sedated were given a stress factor of 1.0–1.1, while patients with increased needs such as the severely malnourished, post major operative procedure or those weaned off mechanical support may be corrected with a higher stress factor of 1.3–1.5. The ASPEN guidelines however proposed that stress factor should not be used as it may result in unintended energy imbalance during critical illness.16,22 Hence the nutritional adequacy of our patients may have been under estimated. This may be especially so in the pre-protocol group whereby there were more trauma and oncology patients for whom a higher stress factor was applied to the estimated energy requirement.
In critically ill children, elevated protein catabolism and sub-optimal nutrition, results in negative nitrogen balance and loss of lean body mass.2,19 Severe depletion of lean body mass inhibits recovery and increases morbidity and mortality.17,19 Hence, prevention of muscle wasting through protein optimisation should be one of the key nutrition goals in the PICU. 2 To date, the amount of protein recommended for critically ill children is based on limited data. 22 Aiming for double recommended dietary allowance of protein intake to aid in the restoration of normal somatic protein status and of nitrogen balance during the initial post-traumatic phase of critical illness in PICU patients had previously been proposed. 19 This recommendation would be higher than that estimated for our patients and aiming for a higher protein intake may improve protein delivery. However, care has to be taken to avoid toxicity in patients with renal or hepatic dysfunction. 22 More research is therefore required to determine whether providing critically ill children with a higher amount of protein would truly aid in whole body protein synthesis. 10
While higher caloric formulae (more than 1 kcal/mL) can be incorporated into the feeding protocol in view of inadequate calorie provision being demonstrated in our study group, it should only be considered in selected patient groups (e.g. patients with major burns and trauma). 1 Such formulae have raised osmolalities and may increase the risk of osmotic diarrhea.23,24 As patients are expected to meet their nutrition adequacy if goal volume has been achieved in the absence of fluid restriction, standardisation of the protocol with a higher caloric formula may pose a risk of overfeeding in the critically ill patients. Overfeeding in critically ill patients may prolong their needs for assisted breathing due to the increase in ventilatory work with increase carbon dioxide production.1,22 This is of possible concern in our group of PICU population as majority of patients were admitted for respiratory indications. Other detrimental effects of overfeeding include increased risk of liver impairment and infection due to hyperglycemia. 22 Thus, one possible consideration to improve our feeding protocol is to aim for goal volume to be achieved faster rather than using a higher caloric formula.
Despite the push for early enteral feeding and optimising nutrition through the use of a feeding protocol in the PICU, multiple barriers in the PICU makes it challenging to deliver the optimal nutrition even in the presence of a feeding protocol. Common barriers include fluid restriction, fasting for clinical interventions (e.g. radiological procedures, endotracheal tube intubation or extubation) and feed intolerance. Our current study demonstrated that the overall rate of enteral feeding interruption was high with 83% of our patients experiencing at least one episode of feed interruption. Similar to the findings from Mehta et al., fasting for intubation or extubation was one of the most common reasons for feed interruptions in the PICU. 15 Their findings also showed that feed interruption for the purpose of endotracheal tube intubation or extubation was mostly avoidable with patients being fasted longer than required. As reflected from our findings, the number of hours for which feeds were held for similar procedures were inconsistent and varied widely. Greater consideration of procedure times and communication between PICU staff may help to reduce the occasions of avoidable prolonged fasting. 15 Being aware that full 24 hours feeding is unlikely to be achievable and knowing that the median feed interruption time is close to two hours per day, one way to optimise feed provision may be to provide catch up feeds in the remainder 20–22 hours of the day. This has been implemented in an adults’ feeding protocol, which has been shown to be safe and feasible.25,26
High GRV was the most common reason noted in relation to feed intolerance. According to Martinez et al., 16 GRV is prevalent in PICU feeding protocols as a marker for monitoring feed. However, both the ASPEN and ESPGHAN guidelines for EN algorithm recommendations do not support using GRV as a marker for feed intolerance.22,27 The practice of withholding feeds in view of GRV results in unnecessary EN interruption which in turn delays optimisation of EN. 28 In our protocol, re-feeding of GRV was not practiced, instead we considered the use of a motility agent if GRV was still high despite holding off one feed. However, the evidence for the use of motility agents and the optimal dose in children is still inadequate and unclear.2,7 More research is therefore required to derive a consensus on defining feed intolerance with recommendations suggested to treat intolerance so that unnecessary feed interruptions can be avoided.
Our current study only involved a small sample size, and thus not powered to evaluate clinical outcomes such as LOS, mortality and incidence of nosocomial infections. Our feeding protocol did not show significant improvement in nutrient provision. This could be because our current protocol lacks full agreement with pediatric-specific guidelines for EN protocol recommendations and also lacks a clear definition for feed intolerance. Indeed, we acknowledge that although we and other practitioners/investigators found it challenging to adhere to national guidelines, future revision of our protocol should take into account these guidelines more strictly. 16 We also acknowledge the potential harm in over-feeding; future revision to our protocol will also take this into account and aim to optimise feeds to avoid both under- and over-feeding.
Defining feed intolerance and providing recommendations based on symptoms for intolerance will assist in minimising unnecessary feed interruption. Furthermore, fasting time guidelines for clinical procedures should be incorporated into the feeding protocol. Another limitation of our study was that the use of the feeding protocol was not mandatory in our PICU. This could have accounted for a longer period required to recruit patients in the post-protocol group compared to the pre-protocol group. Adherence to the protocol was not measured and reasons for non-compliance with the protocol were also not determined as a post-protocol audit was not performed. Hence poor compliance with the feeding protocol could have limited the effectiveness. Moving forward, regular audits to determine nurses’ and doctors’ compliance with the protocol need to be performed.
Conclusion
The implementation of the current feeding protocol was feasible and acceptable to our PICU medical staff, however, it did not improve nutrition adequacy in our PICU. Timeliness to starting feeds was found to be practiced even prior to protocol initiation. In PICU where the standard of practice is initiation of EN within 24 hours of admission, a more aggressive protocol may be indicated. An aggressive feeding protocol that also provides algorithms to minimise both episodes and duration of feed interruptions may provide an avenue to improve nutritional practices in the PICU.
Footnotes
Appendix
Acknowledgements
We thank KK Women’s and Children’s Hospital’s PICU doctors and nursing staff for their support in this study.
Conflict of interest
The authors declare that there are no conflicts of interest.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.