Journal of Parenteral and Enteral Nutrition http://pen.sagepub.com/
Feeding the Gut During Critical Illness−−It Is About Time
Nilesh M. Mehta JPEN J Parenter Enteral Nutr 2014 38: 410 originally published online 11 February 2014 DOI: 10.1177/0148607114522489 The online version of this article can be found at: http://pen.sagepub.com/content/38/4/410
Published by: http://www.sagepublications.com
On behalf of:
The American Society for Parenteral & Enteral Nutrition
Additional services and information for Journal of Parenteral and Enteral Nutrition can be found at: Email Alerts: http://pen.sagepub.com/cgi/alerts Subscriptions: http://pen.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> Version of Record - Apr 22, 2014 OnlineFirst Version of Record - Feb 11, 2014 What is This?
Downloaded from pen.sagepub.com at TEXAS SOUTHERN UNIVERSITY on November 29, 2014
522489
research-article2014
PENXXX10.1177/0148607114522489Journal of Parenteral and Enteral NutritionMehta
Guest Editorial
Feeding the Gut During Critical Illness—It Is About Time Nilesh M. Mehta, MD1
Journal of Parenteral and Enteral Nutrition Volume 38 Number 4 May 2014 410–414 © 2014 American Society for Parenteral and Enteral Nutrition DOI: 10.1177/0148607114522489 jpen.sagepub.com hosted at online.sagepub.com
Keywords pediatrics; life cycle; enteral nutrition; nutrition; critical care; research and diseases
The human body has developed a system of responses aimed at maximizing the chance of survival after injury or sickness, that is, periods of nutrient scarcity. These responses have evolved over millions of years and may have served to provide fuel for the prehistoric human who depended on hunting and gathering for food supplies. Protein catabolism is the salient feature of this stress response, and a significant amount of lean body mass may be lost to provide amino acids for tissue repair, anti-inflammatory response, and wound healing. This stress response is driven by a complex neuroendocrine cascade, which places an energy burden on the host. The provision of optimal amounts of energy to prevent both overfeeding and underfeeding, as well as the provision of optimal protein to prevent lean body mass loss, are the principal goals of nutrition therapy during illness. In modern times, the evolutionary stress response might have different implications for the injured or sick patient due to a number of developments that have altered the magnitude of energy expenditure and the availability of nutrients to the host. The relationship between energy requirement and delivery during illness has significant associations with clinical outcomes during critical illness. However, the available evidence for the optimal nutrient composition, amount, route, and timing of delivery during critical illness is either scant or conflicting. As a result, bedside decisions around nutrient delivery are primarily driven by guidelines based on expert opinion or observational data. There is enthusiasm for early provision of enteral nutrition (EN) based on its perceived benefits during critical illness. The study by Mikhailov et al1 provides yet another reminder of the importance of nutrition during critical illness. Their results highlight the association between early EN and mortality in children admitted to the pediatric intensive care unit (PICU). This publication is an opportune time to review some of the historic beginnings of research in this area, examine the conflicting results of recent studies, discuss the clinical conundrum during this period of ambivalent evidence, and outline best strategies for the future.
copied in 1550 bc from writings dating as far back as 3400 bc. It was not until the discovery and subsequent translation of the Rosetta Stone in early 19th century that it was deciphered. The document describes the practice of administering nutrients such as barley, wine, whey, and milk via rectal enemas. This route of EN was also used during the time of Hippocrates of Cos in the 5th century bc. It was only in the late 16th century that a Venetian physician reported enteral feeding by instilling liquid food into the esophagus. Until the discovery of the circulatory system, the development of vascular access devices, and the mixing of parenteral nutrition (PN) constituents, the enteral route was preferred since it was the only available route for nutrition delivery in an individual unable to sustain eating. However, in recent years, the importance of EN in maintaining gut integrity and its many benefits compared with PN are evident and have promoted EN as the most desired route of nutrient delivery during illness. The concept of balancing the amount of daily enteral nutrient delivery to actual requirement is also not new. Santorio Sanctorius, the 16th-century physiologist from Padua, is known as the father of the physiology of metabolism.2 In his classic experiment, he used a suspended weighing chair (see Figure 1) to frequently measure himself and everything that he consumed or excreted. He used this device to regulate the consumption of a balanced amount of nutrients during each meal. After he began eating, the touching of the chair to the floor was an indication for him to stop eating. This was perhaps the first recorded investigation of energy balance. The quest for the optimal balance between energy intake and energy expenditure continues today. With the advent of gas exchange measurement technology, energy expenditure can now be determined. Indirect calorimetry (IC) has illustrated the unpredictability of From the 1Division of Critical Care, Department of Anesthesiology, Perioperative and Pain Medicine, Children’s Hospital, Boston, Massachusetts. Financial disclosure: None declared.
History of Nutrition—Enteral Route and Energy Balance In the library of the University of Leipzig (Germany) lies the Ebers Papyrus, one of the oldest preserved medical documents. The papyrus is in hieratic Egyptian writing and was probably
This guest editorial originally appeared online on February 11, 2014. Corresponding Author: Nilesh M. Mehta, MD, Director of Critical Care Nutrition, MSICU Office, Bader 634 Childrens Hospital, 300 Longwood Ave, Boston, MA 2115, USA. Email: [email protected]
Downloaded from pen.sagepub.com at TEXAS SOUTHERN UNIVERSITY on November 29, 2014
Mehta
411
Figure 1. Sanctorius’s seat balance. From “Medicina statica: Being the Aphorisms of Sanctorius.” Printed in London 1773.
energy expenditure in patients as well as variability over time within individual patients. Standard equations based on healthy individuals are often inaccurate predictors of energy expenditure in critically ill patients. We are now increasingly aware of the risks of underfeeding and overfeeding critically ill children and the potential impact of these unintended imbalances on clinical outcomes. The optimal nutrition strategy in our modern-day intensive care units (ICUs) is to focus on determining the appropriate amount of energy required for each patient and deliver it via the enteral route (where feasible) in a safe manner.
The Current Study Mikhailov et al1 have described the association between early EN (EEN) and clinical outcomes in children admitted to 12 PICUs in North America. They used the VPS database to identify nutrition and clinical variables in more than 5105 children with a median age of 2.4 years and a minimum length of PICU stay of 4 days. Additional nutrition data were retrospectively abstracted from medical records. All data, including outcomes, were recorded for the first 4 days in the PICU. With an overall mortality of 5.3%, the cohort is representative of the multidisciplinary group of children in most PICUs in the United States. The authors excluded children with existing malnutrition, with
a weight-for-age z score
Feeding the Gut During Critical Illness−−It Is About Time
Nilesh M. Mehta JPEN J Parenter Enteral Nutr 2014 38: 410 originally published online 11 February 2014 DOI: 10.1177/0148607114522489 The online version of this article can be found at: http://pen.sagepub.com/content/38/4/410
Published by: http://www.sagepublications.com
On behalf of:
The American Society for Parenteral & Enteral Nutrition
Additional services and information for Journal of Parenteral and Enteral Nutrition can be found at: Email Alerts: http://pen.sagepub.com/cgi/alerts Subscriptions: http://pen.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> Version of Record - Apr 22, 2014 OnlineFirst Version of Record - Feb 11, 2014 What is This?
Downloaded from pen.sagepub.com at TEXAS SOUTHERN UNIVERSITY on November 29, 2014
522489
research-article2014
PENXXX10.1177/0148607114522489Journal of Parenteral and Enteral NutritionMehta
Guest Editorial
Feeding the Gut During Critical Illness—It Is About Time Nilesh M. Mehta, MD1
Journal of Parenteral and Enteral Nutrition Volume 38 Number 4 May 2014 410–414 © 2014 American Society for Parenteral and Enteral Nutrition DOI: 10.1177/0148607114522489 jpen.sagepub.com hosted at online.sagepub.com
Keywords pediatrics; life cycle; enteral nutrition; nutrition; critical care; research and diseases
The human body has developed a system of responses aimed at maximizing the chance of survival after injury or sickness, that is, periods of nutrient scarcity. These responses have evolved over millions of years and may have served to provide fuel for the prehistoric human who depended on hunting and gathering for food supplies. Protein catabolism is the salient feature of this stress response, and a significant amount of lean body mass may be lost to provide amino acids for tissue repair, anti-inflammatory response, and wound healing. This stress response is driven by a complex neuroendocrine cascade, which places an energy burden on the host. The provision of optimal amounts of energy to prevent both overfeeding and underfeeding, as well as the provision of optimal protein to prevent lean body mass loss, are the principal goals of nutrition therapy during illness. In modern times, the evolutionary stress response might have different implications for the injured or sick patient due to a number of developments that have altered the magnitude of energy expenditure and the availability of nutrients to the host. The relationship between energy requirement and delivery during illness has significant associations with clinical outcomes during critical illness. However, the available evidence for the optimal nutrient composition, amount, route, and timing of delivery during critical illness is either scant or conflicting. As a result, bedside decisions around nutrient delivery are primarily driven by guidelines based on expert opinion or observational data. There is enthusiasm for early provision of enteral nutrition (EN) based on its perceived benefits during critical illness. The study by Mikhailov et al1 provides yet another reminder of the importance of nutrition during critical illness. Their results highlight the association between early EN and mortality in children admitted to the pediatric intensive care unit (PICU). This publication is an opportune time to review some of the historic beginnings of research in this area, examine the conflicting results of recent studies, discuss the clinical conundrum during this period of ambivalent evidence, and outline best strategies for the future.
copied in 1550 bc from writings dating as far back as 3400 bc. It was not until the discovery and subsequent translation of the Rosetta Stone in early 19th century that it was deciphered. The document describes the practice of administering nutrients such as barley, wine, whey, and milk via rectal enemas. This route of EN was also used during the time of Hippocrates of Cos in the 5th century bc. It was only in the late 16th century that a Venetian physician reported enteral feeding by instilling liquid food into the esophagus. Until the discovery of the circulatory system, the development of vascular access devices, and the mixing of parenteral nutrition (PN) constituents, the enteral route was preferred since it was the only available route for nutrition delivery in an individual unable to sustain eating. However, in recent years, the importance of EN in maintaining gut integrity and its many benefits compared with PN are evident and have promoted EN as the most desired route of nutrient delivery during illness. The concept of balancing the amount of daily enteral nutrient delivery to actual requirement is also not new. Santorio Sanctorius, the 16th-century physiologist from Padua, is known as the father of the physiology of metabolism.2 In his classic experiment, he used a suspended weighing chair (see Figure 1) to frequently measure himself and everything that he consumed or excreted. He used this device to regulate the consumption of a balanced amount of nutrients during each meal. After he began eating, the touching of the chair to the floor was an indication for him to stop eating. This was perhaps the first recorded investigation of energy balance. The quest for the optimal balance between energy intake and energy expenditure continues today. With the advent of gas exchange measurement technology, energy expenditure can now be determined. Indirect calorimetry (IC) has illustrated the unpredictability of From the 1Division of Critical Care, Department of Anesthesiology, Perioperative and Pain Medicine, Children’s Hospital, Boston, Massachusetts. Financial disclosure: None declared.
History of Nutrition—Enteral Route and Energy Balance In the library of the University of Leipzig (Germany) lies the Ebers Papyrus, one of the oldest preserved medical documents. The papyrus is in hieratic Egyptian writing and was probably
This guest editorial originally appeared online on February 11, 2014. Corresponding Author: Nilesh M. Mehta, MD, Director of Critical Care Nutrition, MSICU Office, Bader 634 Childrens Hospital, 300 Longwood Ave, Boston, MA 2115, USA. Email: [email protected]
Downloaded from pen.sagepub.com at TEXAS SOUTHERN UNIVERSITY on November 29, 2014
Mehta
411
Figure 1. Sanctorius’s seat balance. From “Medicina statica: Being the Aphorisms of Sanctorius.” Printed in London 1773.
energy expenditure in patients as well as variability over time within individual patients. Standard equations based on healthy individuals are often inaccurate predictors of energy expenditure in critically ill patients. We are now increasingly aware of the risks of underfeeding and overfeeding critically ill children and the potential impact of these unintended imbalances on clinical outcomes. The optimal nutrition strategy in our modern-day intensive care units (ICUs) is to focus on determining the appropriate amount of energy required for each patient and deliver it via the enteral route (where feasible) in a safe manner.
The Current Study Mikhailov et al1 have described the association between early EN (EEN) and clinical outcomes in children admitted to 12 PICUs in North America. They used the VPS database to identify nutrition and clinical variables in more than 5105 children with a median age of 2.4 years and a minimum length of PICU stay of 4 days. Additional nutrition data were retrospectively abstracted from medical records. All data, including outcomes, were recorded for the first 4 days in the PICU. With an overall mortality of 5.3%, the cohort is representative of the multidisciplinary group of children in most PICUs in the United States. The authors excluded children with existing malnutrition, with
a weight-for-age z score
