Nutrition in General Surgery

Comprehensive vocabulary flashcards covering the nutritional management of surgical and critically ill patients, starvation phases, stress responses, and screening tools.

Hospital Malnutrition Prevalence

Two-thirds of all patients are found to be at-risk on admission, leading to longer length of stay and greater hospital mortality.

ICU Malnutrition Risk

Any critically ill patient staying in the ICU for more than $48\,\text{h}$ should be considered at risk.

Glycogenolytic Phase

Starvation Phase 1 ($0\text{--}24\,\text{hours}$) where hepatic glycogen is the primary fuel source to maintain blood glucose at approximately $4\text{--}6\,\text{mmol/L}$.

Gluconeogenic Phase

Starvation Phase 2 ($1\text{--}3\,\text{days}$) characterized by rapid muscle breakdown and negative nitrogen balance as amino acids, lactate, and glycerol are used for glucose production.

Ketogenic / Adaptation Phase

Starvation Phase 3 ($\ge 3\,\text{days}$) where the body shifts to using fat, producing acetoacetate and $\beta$-hydroxybutyrate to spare protein and reduce the basal metabolic rate by $20\text{--}25\%$..

Protein Catabolism / Decompensation Phase

The final stage of starvation triggered by depleted fat stores, leading to the breakdown of cardiac and respiratory muscle, multi-organ failure, and death.

Metabolic Stress Response

A systemic neuroendocrine and inflammatory reaction to injury (trauma, sepsis, burns, or major surgery) intended for survival but can become maladaptive and organ-damaging in excess.

Ebb Phase

The early phase ($0\text{--}48\,\text{hrs}$) of the stress response characterized by shock physiology, decreased cardiac output, decreased oxygen consumption, and hypermetabolism.

Flow Phase

The hypermetabolic phase following the ebb phase, characterized by increased cardiac output, increased oxygen consumption, and temperature.

Cytopathic Hypoxia

Mitochondrial dysfunction leading to impaired oxygen utilization, frequently seen in cases of severe sepsis.

GLIM Criteria

A global consensus framework for diagnosing malnutrition requiring at least 1 phenotypic criterion (e.g., weight loss, low BMI) and 1 etiologic criterion (e.g., reduced food intake, inflammation).

NRS-2002

Nutritional Risk Screening tool that evaluates weight loss, BMI, food intake, and severity of disease; a score of $\ge 3$ indicates nutritional risk.

NUTRIC Score

A scoring system ($1\text{--}10$) for critically ill patients based on variables like Age, APACHE II, SOFA, and comorbidities to identify those who benefit most from aggressive nutrition therapy.

Body Mass Index (BMI) Malnutrition Threshold

A value below $18.5\,\text{kg/m}^2$ (or below $20\,\text{kg/m}^2$ for the elderly) is used to diagnose malnutrition.

Indirect Calorimetry

The gold-standard method for estimating metabolic energy requirements.

ACCP Standard

A weight-based estimate of energy requirements of approximately $25\,\text{kcal/kg/day}$.

Enteral Nutrition (EN)

The delivery of nutrients directly into the gastrointestinal tract via oral, nasogastric, nasojejunal, PEG, or jejunostomy routes.

Parenteral Nutrition (PN)

The intravenous delivery of nutrients, bypassing the gastrointestinal tract, used when enteral feeding is not an option or fails to meet requirements.

TPN Macronutrient Ratios

A standard practical approach includes a carbohydrate to fat ratio of $70:30$ and protein at $1.3\text{--}2\,\text{g/kg/day}$.

Azotemia

A potential complication of Parenteral Nutrition resulting from a metabolic excess of amino acids.

Refeeding Syndrome (RFS)

A metabolic shift caused by reintroducing food to a starved patient, leading to an insulin surge and life-threatening depletion of plasma potassium, phosphate, and magnesium.

RFS Management Protocol

Includes supplementing thiamine ($200\text{--}300\,\text{mg}$ daily), vitamins, and starting feeding at a low rate of $10\,\text{kcal/kg/d}$, slowly increasing over $4\text{--}7\,\text{days}$.