| Nutritional depletion has been identified as a major cause of post-surgical complications. Causes for nutritional depletion include inadequate intake, surgical stress and the subsequent rise in the metabolic rate of the body. | | Why it happens
Post-operatively, oral intake of foods and liquids is held off, especially in surgeries where there has been handling of the intestines, due to fear of causing problems with the normal gastrointestinal mechanisms. For this reason, surgeons usually wait till they can hear bowel sounds on auscultation with a stethoscope or until the patient passes Flatus.
|  | Once this has been noted, it is determined that the gastrointestinal system is returning to normalcy and consumption of liquids is slowly initiated, which is then followed by semi-solids and solids, based on how well the patient tolerates each stage of restoring normal intake.In addition, early initiation of oral intake has been associated with reduced cost and shorter hospital stay.
| | About 40% of patients are already depleted nutritionally at the time of their admission to the hospital. The extent of nutritional depletion depends on the type of the disorder and the duration it has been present. Chronic disorders will have sapped more micronutrients and can cause weight loss and wasting. A direct relationship has been demonstrated between pre-operative weight loss and increased mortality of the operative procedure.
The consequences of nutritional depletion
Nutritional depletion is associated with changes in body composition, tissue wasting, and impaired functioning of organs which consequently leads to impairments in immune and muscle function. Patients who are nutritionally depleted are at higher risk of cardio-respiratory difficulty and infectious complications.
Changes due to surgery
Metabolic: Due to changes in the secretion of essential chemicals there is a 10% increase in the metabolic rate of the body following surgery. If adequate nutritional support is not provided at this stage, there can be a resultant breakdown of skeletal muscle which can further suppress metabolism. In addition, there is an associated increase in energy expenditure due to hormonal responses that are a consequence of surgical trauma.
Physiological: It has been noted that intestinal permeability is increased two- to four-fold in the post-operative period. This normalizes within 5 days. However, the breakdown of the gut barrier can predispose the body to increased inflammatory response by the body, sepsis, and multi-organ failure.
Protein and caloric requirements
In an average individual weighing about 70 kg, there is approximately 10–11 kg of protein. Daily, there is a protein turnover amounting to between 250 and 300 g. After digestion of proteins, all amino acids are absorbed with the exception of nearly 1 g of nitrogen which is excreted in the stool. Breakdown of proteins accounts for another 50–70 g of amino acids. Since ingested amino acids only contribute to 25 g of free amino acids, there is a stress on the protein metabolism during periods of high requirement, such as that following surgery. If there is provision of adequate energy, most of these amino acids are resynthesized.
Thus, caloric supply or meeting of energy requirements is very important. For this a balanced diet with adequate amounts of carbohydrate, fat, and protein is essential for synthesis of muscle, liver and other organ protein. | | | Nutritional benefits to surgical patients
Parenteral nutrition: This type of nutrition is usually provided to patients in the period immediately following surgery or in those patients who are unable to consume food by mouth. Patients who receive enriched parenteral nutrition have demonstrated better and faster recovery rates and lower complication and morbidity rates.
Enteral/oral nutrition: This type of nutrition can be started 6–8 h following surgery and has a few risks such as risk of aspiration, tendency to cause abdominal cramps and bloating. Even in patients who are unable to chew or swallow, adequate nutrition can be provided in liquid or semisolid form via nasogastric tubes. |  | | Enteral nutrition is preferred over parenteral nutrition as its mode of administration is not very invasive and hence, has fewer chances of inducing infection. Food that is delivered to the gut is better utilized than nutrition delivered through intravenous or other invasive modes. In addition, there are other advantages such as preservation of normal gut flora, maintenance of Immunocompetence and attenuation of the trauma response.
Enteral nutrition can be facilitated by the addition of prepackaged formula products that provide definitive amounts of calories, Essential amino acids and proteins that can help faster recovery and wound healing. |  |
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