POSTOPERATIVE NUTRITIONAL CARE
Nutritional demands for healing
Therapeutic nutrition becomes all the more significant as a means of aiding recovery from surgery. In surgical disease and related procedures losses are greatly increased, whereas at the same time replacement from food is diminished or even absent for a period of time. Several nutrients demand particular attention.
Adequate protein intake in the postoperative recovery period is of primary therapeutic concern to replace losses and supply increased demands. A negative nitrogen balance of as much as 20 gm. a day may occur. This represents an actual loss of tissue protein of over a pound a day. In addition to protein losses from tissue breakdown, added loss of plasma proteins occurs through hemorrhage, wound bleeding, and exudates. Increased metabolic losses of protein result also from extensive tissue destruction and inflammation or from infection and trauma. If any degree of prior malnutrition or chronic infection existed, the patient's protein deficit may actually become severe and cause serious complications. There are a number of reasons for this increased protein demand.
TISSUE SYNTHESIS IN WOUND HEALING
Tissue protein can only be synthesizing essential amino acids brought to the tissue by the circulating blood. The eight essential amino acids must come either from diet protein or by intravenous injection. Tissue protein deficiencies are best met by oral feedings. As early as possible an intake of 100 to 200 gm, daily should be attempted to restore lost protein tissues and synthesize new tissue at the wound site.
AVOIDANCE OF SHOCK
A reduction in blood volume, a loss of plasma protein, and a decrease in circulating red blood cell volume contribute to the potential danger of shock. When protein deficiencies exist, this danger is enhanced.
CONTROL OF EDEMA
When the serum protein level is low, edema develops as a result of the loss of the colloidal osmotic pressure required to maintain the normal shift of fluid between the capillaries and the surrounding interstitial tissue. This general edema may affect heart and lung action. Local edema at the surgical site also delays closure of the wound and hinders normal healing processes.
In orthopedic surgery in which extensive bone healing is involved, protein is essential proper callus formation and calcification. A sound protein matrix is mandatory for the anchoring of mineral matter to form bone tissue.
RESISTANCE TO INFECTION
Amino acids are necessary constituents of the proteins involved in body defense mechanisms. These defense agents include antigens, antibodies, blood cells, hormones, and enzymes. Tissue integrity itself is a defense barrier against infection.
Proteins are necessary for the transport of lipids in the body and therefore for the protection of the liver. The liver is a main site of fat metabolism. Proteins present in the liver to combine with fat helps converts the fat and remove it from the liver, thus avoiding the danger of fatty infiltration. Protein provides essential lipo - tropic agents to form lipoproteins, the transport form of fat in the body. It is evident, therefore, that multiple clinical problems may easily develop when protein deficiencies exist. There may be poor wound healing and rupture of suture lines (dehiscence), delayed healing of fracture, anemia, depressed lung and heart function, reduced resistance to infection, extensive weight loss, liver damage, and increased mortality risks.
Water balance is a vital concern after surgery, Adequate fluid therapy is necessary to prevent dehydration, During the postoperative period large water losses may occur from vomiting, hemorrhage, exudates, diuresis, or fever. When drainage is involved, as is common in many surgeries, there is still more fluid loss. Intravenous therapy will supply initial needs, but oral intake should begin as soon as possible and be maintained in sufficient quantity. In complicated cases or seriously ill patient’s cases with extensive drainage, for example, as much as 7 liters of fluid daily may be required.
As is always the case when increased protein is demanded for tissue rebuilding, sufficient nonprotein calories must be supplied for energy to protect the protein. Carbohydrate and fat must therefore be in sufficient supply in the total diet. As protein is increased, the total calories must be increased to a minimum of 2,800 calories per day before protein can he used for tissue repair and not be converted in part to provides energy, In acute stress, as in extensive radical surgery or hums, for example, when protein needs are as high as 2.50 gm. daily, as much as 4,000 to 6,000 calories are required. In addition to its protein-sparing action, carbohydrate also helps avoid liver damage from depletion of glycogen reserves; Fat calories must be adequate but not excessive. Excessive body fat is to be avoided, since fatty tissue heals poorly and is more susceptible to infection, hematoma, and serum collection.
Vitamin C is imperative for wound healing. Its presence is necessary for formation of cementing material in the ground substance of connective tissue, in capillary walls, and in the building up of new tissue. Extensive tissue regeneration, such as in burns or mastectomy, may require as much as 1 gm. or more of vitamin C daily. This is about fifteen to twenty times the normal requirement. As calories and protein are increased, the B vitamins-thiamine, riboflavin, and niacin-must also be increased to provide essential coenzyme factors to metabolize the carbohydrate and protein, Other B-complex vitamins-folic acid. B12 pyridoxine, and pantothenic acid-also have important metabolic roles to play in stress situations and in the formation of hemoglobin. Vitamin K is essential to the blood-clotting mechanism.
Replacement of mineral deficiencies and continued adequacy is essential. In the destruction of tissue, potassium and phosphorus are lost. Electrolyte imbalances of sodium and chloride result from water losses, Iron-deficiency anemia may be developed from blood loss or from fault iron absorption.