Surgery SGD Question #3

3.1 Objective of Inflammation The inflammatory response is an attempt by the body to restore and maintain homeostasis after injury and is an integral part of body defense. Most of the body defense elements are located in the blood and inflammation is the means by which body defense cells and defense chemicals leave the blood and enter the tissue around the injured or infected site. Inflammation is essentially beneficial, however, excess or prolonged inflammation can cause harm.

3.2 What are the key events in Inflammation? Esentially, four occurrences make up the inflammatory mechanism which are triggered and enhanced by a variety of chemical inflammatory mediators: a. Smooth muscles around larger blood vessels contract to slow the flow of blood through the capillary beds at the infected or injured site. This gives more opportunity for leukocytes to adhere to the walls of the capillary and squeeze out into the surrounding tissue. b. The endothelial cells that make up the wall of the smaller blood vessels contract. This increases the space between the endothelial cells resulting in increased capillary permeability. Since these blood vessels get larger in diameter as a result of this, the process is called vasodilation. c. Adhesion molecules are activated on the surface of the endothelial cells on the inner wall of the capillaries. Corresponding molecules on the surface of leukocytes called integrins attach to these adhesion molecules allowing the leukocytes to flatten and squeeze through the space between the endothelial cells. This process is called diapedesis or extravasation. d. Activation of the coagulation pathway causes fibrin clots to physically trap the infectious microbes and prevent their entry into the bloodstream. This also triggers blood clotting within the surrounding small blood vessels to both stop bleeding and further prevent the microorganisms from entering the bloodstream.

3.3 Signs and symptoms of inflammation ●Dolor (pain) ●Calor (heat) ●Rubor (redness) ●Tumor (swelling) ●Functio laesa (loss of function) Redness and heat are due to increased blood flow at body core temperature to the inflamed site; swelling is caused by accumulation of fluid; pain is due to release of chemicals that stimulate nerve endings; while Loss of function has multiple causes but most probably the result of a neurological reflex in response to pain.

Question #4 4. Metabolic response of the body to injury

4.1. Discuss the metabolic response of the body to pure starvation without injury. Differentiate this from what happens in the body in response to injury.

Starvation Injury

Metabolic Rate ↓ ↑↑

Body Fuels Conserved Wasted

Body Proteins Conserved Wasted

Urinary Nitrogen ↓ ↑↑

Weight Loss Slow Rapid

4.2. Explain why during injury, inspite of hyperglycemia, the body cannot use glucose as body fuel and has

to resort to other sources- hence, severe body wasting. Injury and severe infections acutely induce a state of peripheral glucose intolerance

despite ample insulin production. This may occur due to the reduction in the skeletal muscle pyruvate dehydrogenase activity after injury. Thus, there is a decrease in the conversion of pyruvate to Acetyl CoA and entry into the TCA Cycle and (accumulated) pyruvate is shunted to the liver for gluconeogenesis.

This shunting of the glucose away from nonessential organs is mediated by

catecholamine which causes increased hepatic gluconeogenesis and peripheral insulin resistance.

4.3. Compute for the caloric requirement of the above victim prior to injury. Distribute the caloric

requirements for carbohydrates, fats, and proteins respectively.

Computation Calorie Requirement

Caloric Requirement= 25- 30 kcal/ kg BW/ day

= 30 kcal x 80 kg

=2400 kcal

Carbohydrates (60%) 1,440 kcal

Proteins (15%) 360 kcal

Fats (25%) 600 kcal

4.4 Compute for the caloric requirement of the above victim after injury. Distribute the caloric requirement from Carbohydrates, Fats, and Proteins respectively. Male, 176lbs, athlete 176lbs * 1kg/2.2lbs= 80 kg a.) Harris benedict method: (not applicable. Height not given) BEE (men) 66.47 +13.75 (W) + 5.0 (H) – 6.76 (A) kcal/d b.) 25-30 kcal/kg b0dy weight per day 25*80kg 30*80kg

=2000-2400 kcal per day Distribution at catabolic states: 45% carbohydrates *2000-2400kcal = 900-1080 kcal carbohydrates 30% fats*2000-2400kcal=600-720 kcal fats 25% proteins*2000-2400kcal= 500-600 proteins

For normal 60% carbohydrates, 15% proteins, 25% fats

= 4.5 What are the routes of delivery of the computed caloric requirement? a.) Nasoenteric Tubes

-reserved for those with intact mentation and protective laryngeal reflexes to minimize risks of aspiration. b.) Percutaneous Endoscopic Gastrostomy -most common indications for percutaneous endoscopic gastrostomy (PEG) include impaired swallowing mechanisms, oropharyngeal or esophageal obstruction, and major facial trauma. It is frequently used for debilitated patients requiring caloric supplementation, hydration, or frequent medication dosing. It is also appropriate for patients requiring passive gastric decompression. - Relative contraindications for PEG placement include ascites, coagulopathy, gastric varices, gastric neoplasm, and lack of a suitable abdominal site. c.) Percutaneous Endoscopic Gastrostomy-Jejunostomy -for patients who cannot tolerate gastric feedings or who have significant aspiration risks are fed directly past the pylorus through the percutaneous endoscopic gastrostomy-jejunostomy (PEG-J) method. In the percutaneous endoscopic gastrostomy-jejunostomy (PEG-J) method, a 9F to 12F tube is passed through an existing PEG tube, past the pylorus, and into the duodenum. This can be achieved by endoscopic or fluoroscopic guidance. With weighted catheter tips and guidewires, the tube can be further advanced past the ligament of Treitz. d.) Direct Percutaneous Endoscopic Jejunostomy -uses the same techniques as PEG tube placement but requires an enteroscope or colonoscope to reach the jejunum. DPEJ tube malfunctions are probably less frequent than PEG-J tube malfunctions, and kinking or clogging is usually averted by placement of larger-caliber catheters. e.)Surgical Gastrostomy and Jejunostomy - affords direct access to the stomach or small bowel.for a patient undergoing complex abdominal or trauma surgery. The only absolute contraindication to feeding jejunostomy is distal intestinal obstruction. Relative contraindications include severe edema of the intestinal wall, radiation enteritis, inflammatory bowel disease, ascites, severe immunodeficiency, and bowel ischemia. Needle-catheter jejunostomies also can be done with a minimal learning curve. f.) Parenteral Nutrition - is the continuous infusion of a hyperosmolar solution containing carbohydrates, proteins, fat, and other necessary nutrients through an indwelling catheter inserted into the superior vena cava. To obtain the maximum benefit, the calorie:protein ratio must be adequate (at least 100 to 150 kcal/g nitrogen), and both carbohydrates and proteins must be infused simultaneously. When the sources of calories and nitrogen are given at different times, there is a significant decrease in nitrogen utilization. These nutrients can be given in quantities considerably greater than the basic caloric and nitrogen requirements, and this method has proved to be highly successful in achieving growth and development, positive nitrogen balance, and weight gain in a variety of clinical situations.

. 4.6 Why is surgical nutrition important? -to meet the energy requirements for metabolic processes, core temperature maintenance, and repair of injured tissue. Failure to provide adequate nonprotein energy sources will lead to consumption of lean tissue stores -to prevent or reverse the catabolic effects of disease or injury. The ultimate validation for nutritional support in surgical patients should be improvement in clinical outcome and restoration of function -to preserve vital organ function -for restoration of homeostasis through augmented metabolic rates and oxygen consumption, enzymatic preference for readily oxidizable substrates such as glucose, and stimulation of the immune system.