Surgery Main Handout - March 2023 PLE Batch - PDF

TOPNOTCH MEDICAL BOARD PREP SURGERY MAIN DIGITAL HANDOUT BY LOUBOMIR ANTONIO, MD For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for the March 202...

TOPNOTCH MEDICAL BOARD PREP SURGERY MAIN DIGITAL HANDOUT BY LOUBOMIR ANTONIO, MD For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. SPECIFIC CONSIDERATIONS 9. Head, Neck, Thyroid, and Parathyroid 23 IMPORTANT LEGAL INFORMATION 10. Thymus 33 11. Breast 34 The handouts, videos and other review materials, provided by Topnotch Medical Board Preparation Incorporated are duly protected by RA 8293 otherwise known as the 12. Skin 41 Intellectual Property Code of the Philippines, and shall only be for the sole use of the person: 13. Hernia 44 a) whose name appear on the handout or review material, b) person subscribed to Topnotch 14. Abdominal wall, Mesentery, Omentum 49 Medical Board Preparation Incorporated Program or c) is the recipient of this electronic communication. No part of the handout, video or other review material may be reproduced, 15. Esophagus 50 shared, sold and distributed through any printed form, audio or video recording, electronic 16. Stomach 57 medium or machine-readable form, in whole or in part without the written consent of 17. Liver and Gallbladder 67 Topnotch Medical Board Preparation Incorporated. Any violation and or infringement, whether intended or otherwise shall be subject to legal action and prosecution to the full 18. Pancreas 82 extent guaranteed by law. 19. Spleen 89 20. Small Intestines 89 DISCLOSURE 21. Appendix 97 The handouts/review materials must be treated with utmost confidentiality. It shall be the 22. Colon, Rectum, Anus 100 responsibility of the person, whose name appears therein, that the handouts/review materials are not photocopied or in any way reproduced, shared or lent to any person or disposed in any manner. Any handout/review material found in the possession of another BASIC CONSIDERATIONS person whose name does not appear therein shall be prima facie evidence of violation of RA 8293. Topnotch review materials are updated every six (6) months based on the current RESPONSE TO INJURY, FLUIDS trends and feedback. Please buy all recommended review books and other materials listed below. AND NUTRITION THIS HANDOUT IS NOT FOR SALE! FLUIDS, ELECTROLYTES, AND ACID-BASE BODY FLUIDS AND COMPARTMENT INSTRUCTIONS Water constitutes ~50-60% of total body weight To scan QR codes on iPhone and iPad 1. Launch the Camera app on your IOS device Total body weight and total body water (TBW) is relatively 2. Point it at the QR code you want to scan constant for a person and is primarily a reflection of body fat 3. Look for the notification banner at the top oLean tissues (e.g. muscle and solid organs) have higher water of the screen and tap To scan QR codes on Android content than fat and bone 1. Install QR code reader from Play Store Parameter Total Body Water 2. Launch QR code app on your device Adult male 60% 3. Point it at the QR code you want to scan 50% - due to females having higher amount of 4. Tap browse website Adult female fat relative to men Newborns 80% This handout is only valid for the March 2023 PLE batch. TBW is divided into 3 functional fluid compartments: This will be rendered obsolete for the next batch 1. Plasma (extracellular) since we update our handouts regularly. 2. Interstitial fluid (extracellular) Approach to Topnotch Surgery 3. Intracellular fluid Surgery can be overwhelming. But believe it or not, you will now find it easier to integrate concepts and practices for you have already seen these surgical concepts and scenarios in action during your surgical rotations. We encourage you to correlate the concepts being discussed in this handout with actual cases that you had encountered – what was the diagnosis? What surgery was done? Supplementary notes are written in special boxes like this! NORMAL FLUID SUPPLEMENT APPROACH TO TOPNOTCH SURGERY BALANCE Pay close attention to those in bold, italicized, underlined as these are very (i.e., important facts to remember for the subject. Master topics written in our in a 70 kg man) quick review, subject cross overs and end of review question boxes because they provide high yield information, not just for surgery but for the rest of the other subjects as well! Please find the time to finish the whole material “skin-to-skin.” Like any surgery, do not take shortcuts, and please try to stay awake and alert throughout the duration. We suggest that you buy the following: o Schwartz Principles of Surgery, 11th ed. o Schwartz Principles of Surgery, Absite and Board Review 10th ed. Extracellular Fluid Intracellular Fluid o Surgery Platinum Na+ Cations K+, Mg2+ (principal cation of ECF) You will also find several annotations of our faculty in your handout to highlight boards-relevant concepts. Cl-, HCO3- Anions PO4-, proteins Topnotch (principal anions of ECF) Gibbs-Donnan Effect SURGERY – MAIN HANDOUT oSlightly higher protein content (anions) in plasma results in a higher plasma cation composition relative to ISF By Loubomir E. Antonio, MD, FSOSP, FPCS, FPSGS Remember OPPOSITES ATTRACT: ionic interactions occur between substances with 2 different charges (i.e. cations and anions). Contributors: Dr. Rubio Kurt Roland A. Asperas, MD Angeli Andrea S. Cocos-Alcantara, MD Teddy Carpio, MD-MBA Julianne Cristy Lopez, MD-MBA Frinz Moey C. Rubio, MD Patrick Joseph A. Mabugat, RMT, MD Geremiah Edison Daniel C. Llanes, MD OUTLINE PAGE BASIC CONSIDERATIONS 1. Response to Injury, Fluids, and Nutrition 1 2. Surgical Metabolism 4 3. Hemostasis and Transfusion 7 4. Wound Healing 10 5. Sepsis and Septic Shock 11 6. Surgical Site Infections 12 7. Trauma and Burns 13 TOPNOTCH MEDICAL BOARD PREP SURGERY MAIN DIGITAL HANDOUT BY LOUBOMIR ANTONIO, MD Page 1 of 113 For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP SURGERY MAIN DIGITAL HANDOUT BY LOUBOMIR ANTONIO, MD For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. The figure above shows the values we calculate/account for when we do Na K Cl HCO3 our I/O (input vs output). (A) 10 26 10 30 In surgery, we also account for losses like bleeding and/or outputs from (B) 60 10 130 0 the surgical drains – JP Drains, Penrose, NGT, etc. (C) 140 5 104 30 Make sure you account for insensible losses when you make your (D) 140 5 75 115 calculations Dr. Asperas HOLLIDAY-SEGAR METHOD BASAL REQUIREMENTS FOR WATER SUPPLEMENT BODY FLUID AND ELECTROLYTES FLUID VOLUME DAILY REQUIREMENTS WEIGHT VOLUME (ml/kg/day) Fluid (70kg male) 1,500 to 2,500 ml, or (kg) (ml/kg/hr) about 25–30 ml/kg body weight Sodium 1–2 mEq/kg First 10 kg 4 100 A Potassium 0.5–1.0 mEq/kg Next 2 50 B Calcium 1000 mg/day 10-20 kg Electrolytes Phosphate 700 mg 20 Magnesiu Each kg For elderly patients or 300-400mg/day 1 patients with cardiac disease, C m >20 kg this amount is reduced to 15 Chloride 1–2 mEq/kg mL/kg/d Maintenance Fluid Requirement = A + B + C VOLUME OSMOLALITY BODY FLUID Nat K+ CI HCO, 10 kgs: 10kg x 100ml/kg/day = 1L/day! (mL) (mOsm/L) 20 kgs: 10kg x 50 ml/kg/day = 1L + 500ml = 1.5L/day! Saliva 10 26 10 30 1,000 Variable 50 kgs: 30kg x 20ml/kg/day = 1L + 500ml + 600ml = 2.1L/day! Stomach 60 10 130 0 1,500 280 Duodenum 140 5 80 0 1,500 280 Example: Average 70kg man lleum 140 5 104 30 3,000 280 10kg + 10kg + 50kg x 20ml/kg/day = 1L + 500ml + 1L = 2.5L/day Colon 60 35 40 0 750 280 *2500ml / 24 hours = ~104cc/hr. *Chart order: 1L IVF to run at 100cc/hour Pancreas 145 5 75 115 1,000 280 (it means that the patient will be given 100% of his Maintenance Fluid Bile 145 5 100 35 1,000 280 via IVF; TFR is equal to MF given that the patient has no fluid loss and 500 is clinically well hydrated - TFR = MF + OL + SOH) Sweat 50 5 55 0 (+350 mL/°C Variable Dr. Asperas fever) STAGES OF DEHYDRATION Blood 140 5 100 24 5,000 280 MILD MODERATE SEVERE SUPPLEMENT EXTRACELLULAR VOLUME DEFICIT VS. EXCESS (2 to 5% (6 to 10% (11 to 15% EXTRACELLULAR VOLUME DEFICIT BW lost as water) BW lost as water) BW lost as water) Most common fluid disorder in surgical patients Thirst Severe thirst Stupor o Acute volume deficit is associated with cardiovascular and central Low urine Nausea Hypotension nervous system signs volume Dry axilla and groin Severe oliguria o Chronic volume deficit displays tissue signs such as decrease in skin Reduced Tachycardia and Thready pulse turgor and sunken eyes, in addition to acute signs sweating Orthostatic Shock Most common cause of volume deficit in surgical patients is a hypotension Coma loss of GI fluids from nasogastric suction, vomiting, diarrhea, or enterocutaneous fistula Low central venous Death Third-space or nonfunctional ECF losses that occur with pressure sequestration secondary to soft tissue injuries/infections, burns, and Poor skin turgor intraabdominal processes such as peritonitis, obstruction, or Apathy prolonged surgery can also lead to massive volume deficits Oliguria Hemoconcentration EXTRACELLULAR VOLUME EXCESS May be iatrogenic or secondary to renal dysfunction, congestive heart ✔ GUIDE QUESTION failure, or cirrhosis A 55-year-old man with Crohn’s disease had undergone resection of Both plasma and interstitial volumes are increased small bowel and anastomosis. Ten days later, he is found to have bilious Symptoms are primarily pulmonary and cardiovascular drainage of 1 L/d from the drains. He is started on total parenteral In healthy patients, edema and hyperdynamic circulation are nutrition (TPN). Four days later, his arterial blood gases (ABGs) are pH, common and well tolerated. However, the elderly and patients with 7.25; PO2, 98 mm Hg; and PCO2, 40 mmHg. His anion gap is 10. The cardiac disease may quickly develop congestive heart failure and most likely cause is which of the following? pulmonary edema (A) Diabetic ketoacidosis ELECTROLYTE SOLUTIONS FOR PARENTERAL (B) Renal failure ADMINISTRATION (C) Hypovolemic shock (D) Small-bowel fistula Solution Na+ Cl- K+ HCO3- Ca2+ Mg2+ mOsm DKA, renal failure and hypovolemic shock all results to high anion gap 14 10 280- metabolic acidosis. ECF 4 27 5 3 2 3 310 Lactated SUPPLEMENT: ACID BASE BALANCE 130 109 4 28 3 273 Ringer’s ANION GAP 0.9% NSS 154 154 308 Anion gap is an index of unmeasured anions D5 0.45% AG = 𝑁𝑎 − (𝐶𝑙 + 𝐻𝐶𝑂!) N= 20 mEq/l) resin such as Kayexalate that binds K+ in exchange for Na+ Mineralocorticoid excess oWhen ECG changes are present, calcium chloride or calcium Profound potassium depletion gluconate (5-10 ml of 10% solution) should be administered Chloride sparing (urinary chloride < 20 mEq/l) immediately Loss from gastric secretions (emesis or nasogastric suction) All measures are temporary, lasting from 1 to 4 hours. Dialysis should Diuretics be considered in severe hyperkalemia when conservative measures fail. Excess administration of alkali Dr. Asperas Acetate in parenteral nutrition 4. HYP0KALEMIA Citrate in blood transfusions More common than hyperkalemia in the surgical patient Antacids Caused by inadequate K+ intake, excessive renal K+ excretion, K+ Bicarbonate Milk-alkali syndrome loss in pathologic GI secretions, or intracellular shifts from IMPAIRED BICARBONATE EXCRETION metabolic alkalosis or insulin therapy Decreased glomerular filtration (as seen in CKD) Clinical manifestations: Increased bicarbonate reabsorption (hypercarbia or potassium oPrimarily related to failure of normal contractility of GI smooth depletion) muscle (ileus, constipation), skeletal muscle (decreased reflexes, weakness, paralysis), and cardiac muscle (arrest) COMMON ELECTROLYTE ABNORMALITIES ECG changes: SODIUM oU waves, T-wave flattening, ST-segment changes, and 1. HYPERNATREMIA arrhythmias (with digitalis therapy) Results from either a loss of free water or a gain of sodium in Treatment: Potassium repletion, the rate is determined by the excess of water symptoms oAssociated with either an increased, normal, or decreased oMild, asymptomatic hypokalemia: oral repletion is adequate extracellular volume (KCl 40 mEq per enteral access x 1 dose) Clinical manifestations: oAsymptomatic hypokalemia, not tolerating enteral nutrition: oSymptoms are rare until serum sodium concentration KCl 20 mEq IV q2h x 2 doses (slow infusion) exceeds 160 mEq/L oIf IV repletion is required, usually no more than 10 mEq/h is oMostly central nervous system in nature (restlessness, advisable in an unmonitored setting irritability, seizures, coma) due to hyperosmolarity oK+ supplementation can be increased to 40 mEq/h when oMay lead to subarachnoid hemorrhage and death accompanied by continuous ECG monitoring, and even more in Treatment: Management of water deficit the case of imminent cardiac arrest from a malignant oIn hypovolemic patients, volume should be restored with arrhythmia associated hypokalemia normal saline before concentration abnormality is addressed Caution should be done when oliguria or impaired renal function is oOnce adequate volume is achieved, water deficit is replaced coexistent! Also, be mindful of the infusion rates/concentration of using a hypotonic fluid Potassium for it may cause IV burns! Dr. Asperas oRate of fluid administration should be titrated to achieve a 5. HYPERcalcemia decrease in serum sodium concentration of no more than 1 mEq/L/h Serum calcium level above the normal range of 8.5-10.5 oOverly rapid correction can lead to cerebral edema and mEq/l or an increase in ionized calcium above 4.2-4.8 mg/dl herniation oCritical level for serum calcium is 15 mEq/L, when symptoms noted earlier may rapidly progress to death 2. HYPONATREMIA Caused by primary hyperparathyroidism in the outpatient Occurs when there is an excess of extracellular water relative to setting and malignancy in hospitalized patients sodium Clinical manifestations: Neurologic impairment, Extracellular volume can be high, normal, or low musculoskeletal weakness and pain, renal dysfunction, and GI In most cases, sodium concentration is decreased as a symptoms consequence of either sodium depletion or dilution ECG changes: shortened QT interval, prolonged PR and QRS Clinical manifestations: intervals, increased QRS voltage, T-wave flattening and oSymptomatic hyponatremia does not occur until serum widening, and atrioventricular block sodium level is 120 mEq/l Treatment: Aimed at repleting the associated volume deficit and oPrimarily central nervous system in origin (headache, then inducing a brisk diuresis with normal saline confusion, seizures, coma) associated increases in intracranial oTreatment is required when hypercalcemia is symptomatic, pressure which usually occurs when the serum level exceeds 12 Treatment: Water restriction and, if severe, the mEq/l administration of sodium 6. HYPOcalcemia oIf symptomatic, 3% normal saline should be used to increase Serum calcium level below 8.5 mEq/l or a decrease in the the sodium by no more than 1 mEq/L/h until the serum ionized calcium level below 4.2 mg/dl sodium reaches 130 mEq/l or symptoms are improved Causes include pancreatitis, malignancies associated with oIf asymptomatic, correction should increase the sodium level increased osteoblastic activity (breast and prostate cancer), by no more than 0.5 mEq/L/hr. to a maximum increase of 12 massive soft tissue infections such as necrotizing fasciitis, renal mEq/l/d failure, pancreatic and small bowel fistulas, hypoparathyroidism, POTASSIUM toxic shock syndrome, and tumor lysis syndrome Transient hypocalcemia also occurs after removal of a 3. HYPERKALEMIA parathyroid adenoma due to atrophy of the remaining gland Serum K+ concentration above the normal range of 3.5-5 mEq/L and avid bone remineralization Caused by excessive K+ intake, increased release of K+ from cells, Neuromuscular and cardiac symptoms do not occur until the or impaired K+ excretion by the kidneys ionized fraction falls below 2.5 mg/dl Clinical manifestations: Clinical manifestations: Neuromuscular symptoms with oMostly GI (nausea/vomiting, diarrhea), neuromuscular decreased cardiac contractility (weakness, paralysis), and cardiovascular (arrhythmia, arrest) TOPNOTCH MEDICAL BOARD PREP SURGERY MAIN DIGITAL HANDOUT BY LOUBOMIR ANTONIO, MD Page 3 of 113 For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly.  TOPNOTCH MEDICAL BOARD PREP SURGERY MAIN DIGITAL HANDOUT BY LOUBOMIR ANTONIO, MD For inquiries visit www.topnotchboardprep.com.ph or https://www.facebook.com/topnotchmedicalboardprep/ This handout is only valid for the March 2023 PLE batch. This will be rendered obsolete for the next batch since we update our handouts regularly. ECG changes: Prolonged QT interval, T-wave inversion, heart NUTRITIONAL WHO CRITERIA BMI CUT- ASIAN CRITERIA BMI block and ventricular fibrillation STATUS OFF (kg/m²) CUT-OFF (kg/m²) Treatment: Calcium supplementation and correction of other Underweight