Micronutrients in Critical Illness

Perioperative micronutrients, macroscopic benefits?

'Micronutrients' are vitamins and minerals vital for healthy metabolic function, wound healing and disease and infection prevention. Micronutrients may play a role in significantly improving postoperative recovery and indices of patient comfort; however, minimal research exists for surgical patients. Furthermore, current guidelines on perioperative nutrition have a macronutrient focus which may fail to guide detection and treatment of the subclinical micronutrient deficiency in a patient who is not obviously malnourished. Limited research into supplementation of some micronutrient deficiencies shows favourable results; however, given the financial implications of wound care, the prevalence of micronutrient deficiency and possible benefits from attention to micronutrition for postoperative recovery, further research into this area is urgently warranted. Interventions to guide optimal future clinical practice are suggested.

Serum selenium and zinc levels in critically ill surgical patients

PURPOSE

The authors designed this study to determine how serum selenium and zinc affect the outcomes of critically ill surgical patients.

METHODS

The medical records of 162 patients admitted to a surgical intensive care unit (ICU) from October 2010 to July 2012 and managed for more than 3 days were retrospectively investigated.

RESULTS

Overall, the mean patient age was 61.2 ± 15.0 years, and the median ICU stay was 5 (3-115) days. The mean Acute Physiologic and Chronic Health Evaluation II score was 18.0 ± 8.0. Eighteen (11.1%) of the study subjects died in ICU. mean selenium levels were 83.5 ± 23.8 ng/dL in the survivor group and 83.3 ± 29.6 ng/dL in the nonsurvivor group, and corresponding mean zinc levels were 46.3 ± 21.7 and 65.6 ± 41.6 μg/dL, respectively. Mean selenium concentrations were significantly different in patients with and without shock (77.9 ± 25.4 and 87.2 ± 23.1 ng/dL, P = .017). Furthermore, mean serum selenium was lower in patients with sepsis than in traumatic or simply postoperative patients (P < .001 and P = .038). Serum Zn was significantly lower in patients with sepsis than in patients with trauma (43.4 ± 25.4 μg/dL vs 54.8 ± 28.1 μg/dL, P = .038).

CONCLUSIONS

To determine the effects of serum selenium and zinc levels on critically ill surgical patients, a large-scale prospective study is needed.

Stressor states and the cation crossroads

Neurohormonal activation involving the hypothalamic-pituitary-adrenal axis and adrenergic nervous and renin-angiotensin-aldosterone systems is integral to stressor state-mediated homeostatic responses. The levels of effector hormones, depending upon the degree of stress, orchestrate the concordant appearance of hypokalemia, ionized hypocalcemia and hypomagnesemia, hypozincemia, and hyposelenemia. Seemingly contradictory to homeostatic responses wherein the constancy of extracellular fluid would be preserved, upregulation of cognate-binding proteins promotes coordinated translocation of cations to injured tissues, where they participate in wound healing. Associated catecholamine-mediated intracellular cation shifts regulate the equilibrium between pro-oxidants and antioxidant defenses, a critical determinant of cell survival. These acute and chronic stressor-induced iterations in extracellular and intracellular cations are collectively referred to as the cation crossroads. Intracellular cation shifts, particularly excessive accumulation of Ca2+, converge on mitochondria to induce oxidative stress and raise the opening potential of their inner membrane permeability transition pores (mPTPs). The ensuing loss of cationic homeostasis and adenosine triphosphate (ATP) production, together with osmotic swelling, leads to organellar degeneration and cellular necrosis. The overall impact of iterations in extracellular and intracellular cations and their influence on cardiac redox state, cardiomyocyte survival, and myocardial structure and function are addressed herein.

Cation dyshomeostasis and cardiomyocyte necrosis: the Fleckenstein hypothesis revisited

An ongoing loss of cardiomyocytes to apoptotic and necrotic cell death pathways contributes to the progressive nature of heart failure. The pathophysiological origins of necrotic cell loss relate to the neurohormonal activation that accompanies acute and chronic stressor states and which includes effector hormones of the adrenergic nervous system. Fifty years ago, Albrecht Fleckenstein and coworkers hypothesized the hyperadrenergic state, which accompanies such stressors, causes cardiomyocyte necrosis based on catecholamine-initiated excessive intracellular Ca(2+) accumulation (EICA), and mitochondrial Ca(2+) overloading in particular, in which the ensuing dysfunction and structural degeneration of these organelles leads to necrosis. In recent years, two downstream factors have been identified which, together with EICA, constitute a signal-transducer-effector pathway: (i) mitochondria-based induction of oxidative stress, in which the rate of reactive oxygen metabolite generation exceeds their rate of detoxification by endogenous antioxidant defences; and (ii) the opening of the mitochondrial inner membrane permeability transition pore (mPTP) followed by organellar swelling and degeneration. The pathogenesis of stress-related cardiomyopathy syndromes is likely related to this pathway. Other factors which can account for cytotoxicity in stressor states include: hypokalaemia; ionized hypocalcaemia and hypomagnesaemia with resultant elevations in parathyroid hormone serving as a potent mediator of EICA; and hypozincaemia with hyposelenaemia, which compromise antioxidant defences. Herein, we revisit the Fleckenstein hypothesis of EICA in leading to cardiomyocyte necrosis and the central role played by mitochondria.

Bone physiology and therapeutics in chronic critical illness

Modern medical practices allow patients to survive acute insults and be sustained by machinery and medicines for extended periods of time. We define chronic critical illness as a later stage of prolonged critical illness that requires tracheotomy. These patients have persistent elevations of inflammatory cytokines, diminished hypothalamic-pituitary function, hypercatabolism, immobilization, and malnutrition. The measurement of bone turnover markers reveals markedly enhanced osteoclastic bone resorption that is uncoupled from osteoblastic bone formation. We review the mechanisms by which these factors contribute to the metabolic bone disease of chronic critical illness and suggest potential therapeutics.

Optimizing the patient for surgical treatment of the wound

Plastic surgeons are consulted often to close wounds that fail or are difficult to heal. Optimizing the patient's medical condition before surgical closure of a wound can mean the difference between a successful outcome and an undesirable one. It is imperative that plastic surgeons have an extensive knowledge of the modifiable risk factors affecting the wound-healing process and their subsequent complications. This knowledge allows the surgeon to tailor the treatment options and intervene when appropriate to optimize outcomes for successful surgical closure of a wound. Whether the impairments to wound healing and closure are local or systemic, they must be addressed appropriately.

Nutritional supplementation: is it necessary for everybody?

Mineral nutrients, vitamins, and trace elements are essential for the growth and development of a multicellular organism. Today, an adequate supply of nutrients is often unattainable solely through a well-balanced diet, so a targeted, individually designed dietary supplement regime is necessary. Nutrient deficiency, which is impossible to detect through plasma levels alone, is reliably detected through the intracellular measurement of the nutrient levels in the blood. Two case studies presented here indicate the need for supplementation as improvement in nutritional behavior could not replenish already exhausted nutrient reservoirs. Only supplementation was able to significantly boost nutrient levels and confer beneficial effects on general welfare, physical performance, and resistance to infections. Therefore, it appears that nutritional supplements are advisable for everyone, but more research is needed, especially on an intracellular level, to corroborate these findings.

Nutrition and Wound Healing

The relationship between nutrition and wound healing--after injury or surgical intervention--has been recognized for centuries. There is no doubt that adequate carbohydrate, fat, and protein intake is required for healing to take place, but research in the laboratory has suggested that other specific nutritional interventions can have significant beneficial effects on wound healing. Successful translation into the clinical arena, however, has been rare. A review of normal metabolism as it relates to wound healing in normoglycemic and diabetic individuals is presented. This is followed by an assessment of the current literature and the data that support and refute the use of specialized nutritional support in postoperative and wounded patients. The experimental evidence for the use of arginine, glutamine, vitamins, and micronutrient supplementation is described. Most of the experimental evidence in the field supporting the use of specialized nutritional support has not been borne out by clinical investigation. A summary of the clinical implications of the data is presented, with the acknowledgment that each patient's plan of care must be individualized to optimize the relationship between nutrition and wound healing.

Le scorbut n'a pas disparu : histoire d'une maladie réémergente

BACKGROUND

Scurvy is the clinical manifestation of vitamin C deficiency. It is historically linked to the era of great maritime expeditions. But it is remerging in Western countries as in France.

SITUATION

Nowadays, scurvy mainly affects homeless populations of large occidental cities and the isolated and malnourished inhabitants of developing countries. The clinical presentations of scurvy are numerous and often misleading and its evolution without treatment is always lethal. After years of wanderings and research, the physiopathological mechanisms of scurvy were finally understood, due to the will of outstanding personalities who took the risk to brave the established superstitions in order to apply a strict medical approach.

PERSPECTIVES

Scurvy must still be prevented in at risk-populations. Indeed a pocket meal enriched with vitamin C is distributed to homeless people in Paris.

The role of nutrition in the management of lower extremity wounds

From 3000 BC, healers have understood the importance of nutrition in wound care and used nutritional supplements to aid healing. Many of the teachings from Hippocrates, the father of modern-day medicine, clearly state his firm belief that good health can be achieved through nutrition. In the early 1900s when advances in biochemistry were frequent, many of the essential constituents of nutrition were characterized, which formed the basis for many animal and human wound-healing experiments. This led to the discovery of vitamin C, zinc, and many other components essential for the orderly progression of healing. Modern-day research has concentrated on finding nutritional components that can enhance healing through supra-physiological doses, such as in the use of the amino acids arginine and carnitine. However, clinicians need to be aware that approximately 50% of patients admitted to the hospital are malnourished, requiring dietary supplementation; appropriate nutritional assessment and advice therefore should be an integral part of all wound management. This review provides an up-to-date commentary on the role of nutrition in wound care, with specific emphasis on lower limb wounds, from a historical perspective, and within it both the biomedical approach and current herbalist practices are considered.

The role of initial monitoring of routine biochemical nutritional markers in critically ill children

AIMS

The objectives of this study were to determine whether abnormal values of routine laboratory parameters at admission predict outcome and changes in anthropometric parameters in critically ill children during intensive care unit (ICU) stay and to discuss the clinical implications of abnormalities.

STUDY DESIGN

This is a prospective descriptive study in a tertiary multidisciplinary pediatric ICU. Serum urea, albumin, triglycerides and magnesium were measured in samples obtained from 105 children (age, 7 days-16 years) within the first 24 h after their admission. The prevalences of abnormalities in these parameters as well as their possible association with outcome (length of stay, days on mechanical ventilation) and changes in nutritional status (changes in S.D. scores for weight, mid upper arm circumference and calf circumference) between admission and discharge were assessed.

RESULTS

Prevalences of hypomagnesemia, hypertriglyceridemia, uremia and hypoalbuminemia were 20%, 25%, 30% and 52%, respectively, with no significant associations between the different disorders. Except for uremia, no significant association was found between abnormalities in biochemical parameters and changes in S.D. scores of anthropometric measurements. Children with uremia showed larger declines in S.D. scores for weight and arm circumference between admission and discharge than children without uremia did. Children with hypertriglyceridemia had longer ventilator dependence (P<.01) and length of stay (P<.001) than children with normal triglyceride levels upon admission had.

CONCLUSIONS

Abnormalities in routine nutritional laboratory parameters were frequently noted in critically ill children at admission. Detection of abnormalities was not predictive of changes in anthropometric parameters during ICU admission but can be important in individualizing nutritional support.

Carences en vitamine C

BACKGROUND

Hypovitaminosis C is frequent in populations at risk (men who live alone, old people, homelessness, patients with psychiatric diseases, foodfaddists,...) and is underestimated in the general population.

STRONG POINTS

Scurvy occurs after 3 months without consumption of ascorbic acid, and is due to lack of consumption fresh fruits and vegetables. Clinical manifestations are weakness, myalgia and arthralgia, vascular purpura and hemorrhagic syndrome, and later the stomatologic manifestations: gingivorragia and loss of teeth. Biological signs are nonspecific: anemia, hypocholesterolemia, hypoalbuminemia. Clinical suspicion must be confirmed by a low level of ascorbic acid (<2.5 mg/l), but this value needs to be interpretated according to the presence of an acute phase response. Leucocyte ascorbic acid level reflects total body store and is more reliable, but not available in practice. Treatment consists in administration of 1 g vitamin C per day during 15 days.

PERSPECTIVES

Vitamin C depletion (serum ascorbic acid level between 2 and 5 mg/l) may occur long-term complications such as increase cardiovascular and neoplasic risks or cataract. The new recommended dietary allowance of vitamin C (110 mg per day for an adult) takes into account of these risks.

The pragmatics of feeding the pediatric patient with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) represents the ultimate pulmonary response to a wide range of injuries, from septicemia to trauma. Optimal nutrition is vital to enhancing oxygen delivery, supporting adequate cardiac contractility and respiratory musculature, eliminating fluid and electrolyte imbalances, and supporting the proinflammatory response. Research is providing a better understanding of nutrients that specifically address the complex physiologic changes in ARDS. This article highlights the pathophysiology of ARDS as it relates to nutrition, relevant nutritional assessment, and important enteral and parenteral considerations for the pediatric patient who has ARDS.

Nutrition and wound healing

The relationship between host nutrition and wound healing has been the subject of study and experimentation for centuries. Despite the many years of study and a substantial knowledge base of the specific processes and factors involved, wound healing remains enigmatic. There is still much to learn about the wound-specific nutritional interventions that are available to improve wound healing. Nutrition profoundly influences the process of wound healing. Nutritional depletion exerts an inhibitory effect, and nutritional supplementation with such positive effectors as arginine can stimulate wound healing. Within this paradigm, the physician should be able to recognize patients who may be expected to have wound healing difficulties and offer early intervention to avoid wound failure.

Practical implications of nutritional support during continuous renal replacement therapy

Continuous blood membrane interactions during continuous renal replacement therapy cause bioincompatibility and low grade inflammatory reactions with potentially adverse consequences on protein metabolism and immunocompetence. In designing a nutritional program for patients receiving this treatment, these adverse metabolic effects, especially the loss of nutritional substrates, must be considered. This review provides a practical overview of nutritional support in acute renal failure, including assessment techniques, determination of nutrient needs, and appropriate intervention for patient support.

Food intake of a typical Brazilian diet among hospitalized malnourished patients

AIM

To verify whether malnourished inpatients receiving a typical Brazilian diet meet their food requirements.

METHODS

Thirty-five consecutive surgical and medical hospitalized adults, able to feed themselves, received rice and beans based diets for 3 consecutive days. All served food was weighed before and after the meals. Nutrient intake was determined and results compared to American Recommended Dietary Allowances (RDA). Malnutrition was defined by the presence of at least one of these criteria: body mass index &lE 18.5 kg/m(2); height-creatinine index << 70%; or albumin level << 3. 5 g/dl.

RESULTS

Malnourished and non-malnourished patients were paired in relation to age, gender, diagnoses and clinical parameters. Despite showing distinct anthropometric parameters and laboratory data, malnourished patients ingested enough quantities of food and met or exceeded RDA for energy and other nutrients.

CONCLUSIONS

Clinically-stable malnourished inpatients, supplied with rice- and beans based diets have adequate energy and nutrient intake, the same occurring for non-malnourished ones.

Trace element and vitamin concentrations and losses in critically ill patients treated with continuous venovenous hemofiltration

OBJECTIVES

To measure the blood concentrations of a number of trace elements and vitamins in critically ill patients and examine their elimination by continuous venovenous hemofiltration (CVVH).

SETTING

Intensive care unit of a tertiary institution.

DESIGN

Prospective, controlled, clinical study.

PATIENTS

Eight critically ill patients requiring renal replacement therapy, nine patients requiring intensive care treatment but not requiring renal replacement therapy, and nine healthy controls.

INTERVENTIONS

Measurement of trace element and vitamin concentrations in blood and ultrafiltrate.

MEASUREMENTS AND MAIN RESULTS

Compared with normal volunteers, critically ill patients requiring CVVH had significantly lower median blood concentrations of vitamin C, vitamin E, selenium, and zinc. During the first 24 hrs of CVVH, there were no changes in the trace element and vitamin concentrations in blood, nor were there differences between pre- and postfilter samples. Micronutrient losses in the ultrafiltrate were small or undetectable except for Vitamin C, chromium, and copper. Compared with normal volunteers, critically ill patients not requiring CVVH also had significantly lower median blood concentrations of vitamin C, vitamin E, selenium, and zinc. There were no differences between the two critically ill groups.

CONCLUSIONS

The clinical significance of the reductions in blood concentrations of selenium, zinc, vitamin C, and vitamin E in critically ill patients and the ultrafiltrate losses of Vitamin C, copper, and chromium remains unclear.

Enteral nutrition in intensive care patients: a practical approach. Working Group on Nutrition and Metabolism, ESICM. European Society of Intensive Care Medicine

Severe protein-calorie malnutrition is a major problem in many intensive care (ICU) patients, due to the increased catabolic state often associated with acute severe illness and the frequent presence of prior chronic wasting conditions. Nutritional support is thus an important part of the management of these patients. Over the years, enteral nutrition (EN) has gained considerable popularity, due to its favorable effects on the digestive tract and its lower cost and rate of complications compared to parenteral nutrition. However, clinicians caring for ICU patients are often faced with contradictory data and difficult decisions when having to determine the optimal timing and modalities of EN administration, estimation of patient requirements, and choice of formulas. The purpose of this paper is to provide practical guidelines on these various aspects of enteral nutritional support, based on presently available evidence.

Selenium and zinc levels in surgical patients receiving total parenteral nutrition

The zinc and selenium levels of 40 surgical patients were monitored pre- and post-TPN. The initial selenium level was low normal, and the initial zinc level was also low. Both selenium and zinc are potent antioxidants involved in cellular defense against free radicals. Surgical patients are at risk for selenium and zinc deficiencies secondary to both increased needs and losses. TPN blood work protocols should include monitoring of selenium and zinc with supplementation of the nutrient solutions, as required.

Management of a patient with advanced AIDS and toxic epidermal necrolysis using human growth hormone and G-CSF

Toxic epidermal necrolysis (TEN) is a serious drug reaction that is occurring with increased frequency among those affected with HIV and AIDS. It carries a grave prognosis for those with advanced AIDS and massive skin involvement. We report a severe case of TEN treated with wound care, intravenous nutrition, human growth hormone (hgh), and granulocyte colony-stimulating factor (G-CSF).