Burns Lecture Notes PDF

SURGERY A LECTURE | DR. BRICCIO ALCANTARA 1 Objectives In children under 3 years old, the head accounts for a Initial evaluation of the burned patient should...

SURGERY A LECTURE | DR. BRICCIO ALCANTARA 1 Objectives In children under 3 years old, the head accounts for a Initial evaluation of the burned patient should follow the: larger relative surface area and should be taken into ○ Initial evaluation (ABCDEs) account when estimating burn size. ○ Learn the pathophysiology of burn injury For smaller or odd-shaped burns, the “rule of the ○ Know the diagnosis and treatment of the di erent palm” where the palmar surface of the patient’s hand, types of causation including the digits, is 1% TBSA (this will be useful in the absence of charts). Key Points (MUST KNOW) Lund and Browder chart gives a more accurate Follow American Burn Association Criteria for referral of a accounting of the true burn size in children and adults. patient to a regional burn center Never administer prophylactic antibiotics other than tetanus vaccination Early excision and grafting of full-thickness and deep partial-thickness burns improve outcomes. Intravenous fluid resuscitation for patients with burns >20% - of total body surface area (children with burns >15% of total - body surface area) should be titrated to mean arterial e pressure (MAP) >60mmHg and appropriate urine output. Initial evaluation Initial evaluation of the burned patient should follow the same initial priorities of all trauma patients and involves 71s four crucial assessments: (1) Airway management (2) Evaluation of other injuries (3) Estimation of burn size (4) Diagnosis of CO and cyanide poisoning How do you diagnose a patient with a traumatic event? ○ A - AIRWAY From Doc Alcantara ○ B - BREATHING ○ C - CIRCULATION Burns Classification to determine this, look for blood pressure Thermal ○ D - DISABILITY Most of burn cases, it’s almost always thermal burns other factors that contribute to the trauma secondary to heat/high-temperature fractures, consciousness Burns are commonly classified as thermal injury ○ E - EXPOSURE Flame, contact, or scald burns Di erence between circulation and breathing? Flame burns - most common cause for hospital ○ Breathing entrance of air into the airways admission of burns. ○ Circulation - the ability of blood to flow into the organs Have the highest mortality. After ABCDE, once the patient is stable, what’s next? Primarily related to their association with - Assess for burn size, because your fluid resuscitation structural fires and the accompanying will depend on the percentage of Total Burn Surface inhalation injury and/or CO poisoning. Area (TBSA) The greater the temperature, the lesser time of exposure for tissue destruction and vice versa. If there are blisters, it will now be categorized as partial-thickness burns. Electrical Potential for cardiac arrhythmias and renal problems A baseline ECG is recommended in all patients with an electrical injury, and a normal ECG in a low-voltage injury ( 25% adults 20% children 10% 2-10% no blood flow) Moist and red Painful - exposed nerve endings ○ Deep partial thickness - pale and quite tense Full Thickness (Third degree) Leathery, painless, and non blanching The graph displays the amount of exposure (x-axis) Epidermis + Dermis + Subcutaneous and the temperature (y-axis). Hallmark: thrombosed vessels underneath The greater the temperature, the less time (exposure) needed for tissue destruction. Fourth Degree Burns The lesser the temperature, the more time (exposure) A ect underlying soft tissue needed for tissue destruction. Fascia, muscles, tendons, nerves, bones Dry, brittle, desiccated bone Categorization of Burns (American Burn Association) Until the bone and muscle Moderate Major Burn Minor Burn Guidelines for Referral to a Burn Center Burn 1. Partial-thickness burns greater than 10% TBSA Stay hydrated & study well! © MED TRANS  SURGERY A LECTURE | DR. BRICCIO ALCANTARA 3 2. Burns involving the face, hands, feet, genitalia, ○ Will heal with minimal or no scarring and is perineum, or major joints most like a superficial partial thickness burn or first-degree burn 3. Third-degree burns in any age group ○ This is not included in the computation. 4. Electrical burns, including lightning injury 5. Chemical burns EFFECTS OF BURN Burn shock 6. Inhalation injury ○ There is third space sequestration (extravascular) 7. Burn injury in patients with complicated pre existing ○ Leaks will occur, leading to hypovolemia (< 60 medical disorders mmhg) 8. Patients with burns and concomitant trauma in which ○ There will be decreased cardiac output, decreased the burn is the greatest risk. If the trauma is the plasma volume, increased extracellular fluid, and dysfunctional renal system. greater immediate risk, the patient may be stabilized ○ Cells that are characteristic of burn shock are in a trauma center before transfer to a burn center. polymorphonuclear leukocytes (PMNs). 9. Burned children in hospitals without qualified There are PMNs and neutrophils as well as CD18, which personnel for the care of children generate proteases and toxic oxygen radicals. 10. Burn injury in patients who will require special social, Prognosis emotional, or rehabilitative intervention Baux score: Mortality = Age + %TBSA Most burn resuscitation formulas estimate fluid Resuscitation: requirements based on burn size measured as a ○ Parkland’s Formula percentage of TBSA (%TBSA). ○ Baxter Formula The “rule of nines” is a crude but quick and e ective ○ Crystalloids Vs Colloids method of estimating burn size. Crystalloids - Lactated ringer’s solution, Minor burns can be treated in the outpatient setting. normal saline solution Those beyond minor burns may be transferred to Colloids - albumin specialized burn units. Resuscitation ZONES OF BURN INJURY The most commonly used formula is the Parkland or Area with the most concentrated injury is called the Baxter formula Zone of coagulation. ○ Consists of 3 - 4 mL/kg per % burn of Lactated ○ Most severely burned portion and is typically Ringer’s, of which half is given during the first - the center of the wound e 8 hours after burn and the remaining half is ○ A ected tissue is coagulated and sometimes o give over the subsequent 16 hours. The most recent American Burn Association consensus frankly necrotic, much like a full thickness burn ○ Will need excision and grafting formula recommends 2 mL/kg per % burn of Lactated ○ Color is very white or can also be very black Ringer’s given towards excessive fluid administration ○ Can expand if Zone or Stasis is not with the traditional formulas (Parkland or Baxter) resuscitated ○ There are modifications as the Parkland The Zone of stasis is the most salvageable portion - formula usually overcompensates, leading to This is peripheral to the zone of coagulation more edema, more circulatory embarrassment ○ Variable degrees of vasoconstriction and why the suggested is 2-4 ml/kg resultant ischemia, much like a second degree ○ Amount will be based on two parameters: burn. Urine output ○ Appropriate resuscitation and wound care Normal (adult): 0.5 - 1 ml/kg may prevent conversion to a deeper wound, To ensure kidney safety but infection or suboptimal perfusion may Hypovolemia may result in result in an increase in burn depth necrosis ○ Responsive to hydration Correction of base deficit ○ Can be pale or reddish in appearance Concept behind continuous fluid requirements ○ Can be lost and converted to a zone of The burn (and/or inhalation injury) drives an coagulation if resuscitation is insu cient or inflammatory response that leads to capillary leak; late. As plasma leaks into the extravascular space, ○ Clinically relevant because many superficial crystalloid administration maintains the intravascular partial-thickness burns will heal with volume nonoperative management, and the majority THEREFORE, if a patient receives a large fluid bolus in of deep partial-thickness burns benefit from a prehospital setting or emergency department, the excision and skin grafting. fluid has likely leaked into the interstitium and the The Zone of Hyperemia are the red streaks on the patient still requires ongoing burn resuscitation edges of the wound according to the estimates. ○ The outermost area of a burn Stay hydrated & study well! © MED TRANS  SURGERY A LECTURE | DR. BRICCIO ALCANTARA 4 Continuation of fluid volumes should depend on the a. Acute pulmonary insu ciency (immediately postburn 12 time since injury, urine output, andbmean arterial to 48 hours) pressure (MAP) b. Pulmonary edema (48-72 hours) As the capillary leak closes, the patient will require less volume to maintain these two resuscitation endpoints. c. Bronchopneumonia (25 days) Children under 20 kg have the additional requirement This is why, in 48-72 hours, we try to shift from Crystalloid to that they do not have su cient glycogen stores to Colloid, because that will always set in maintain an adequate glucose level in response to the Pulmonary edema → Pneumonia → ARDs → Multiple Organ inflammatory response. Failure Acute Respiratory The Parkland formula for the total fluid requirement in 24 Distress syndrome Treatment Plan hours is as follows: Relieve respiratory distress - Escharotomy and/or 3-4 ml x TBSA (%) x body weight (kg); Intubation 50% given in first eight hours; Prevent and/or treat burn shock - insert two large 50% given in next 16 hours. intravenous needles Children receive maintenance fluid in addition, at an Monitor resuscitation - insert foley catheter and hourly hourly rate of: urine output 4 ml/kg for the first 10 kg of body weight plus; Treat Ileus - insert nasogastric tube if >20% TBSA burn 2 ml/kg for the second 10 kg of body weight plus; or intubated 1 ml/kg for >20 kg of body weight ○ Ileus - auscultate for Bowel sounds (such as End point flatus) Urine - adults: 0.5 - 1.0 ml/kg/hour; Tetanus prophylaxis Urine - children: 1.0 - 1.5 ml/kg Baseline laboratory studies (i.e. CBC, Comprehensive Metabolic panel, U/A, Chest X-ray, EKG, Cross-match, Sample computation (Dr. Alcantara did not follow the Arterial Blood Gases, and Carboxyhemoglobin) formula) Clean, debride, and treat the burn wound 70 kg individual with a partial thickness burn with 30% Would you immediately debride blisters or not? TBSA. Patient came in at the ER at 7 am in the - Depends, as long as there is no necrotic tissue then you morning, the time of injury was 3 am (same day). How need not debride 4 x 20 x 10 8400 TBSA much fluids will I give? = - Full thickness, definitely have necrotic tissue, do Early 30 x 70*= 2100 cc 8400/2 =4200 ut Debridement How much will you give for the first eight hours? 525. 1st8n = - This is because the necrotic tissue will further increase ○ 1/3rd of the fluid (700 cc) 5 an infectious process that might be Septic 262 ○ First eight hours will finish atnext lin (basis is =. 11 am the time of injury NOT the time the patient CARBON MONOXIDE POISONING arrived) Schwartz: An important contributor to early mortality in Next 16 hours = give the rest burn patients and often seen in patients with inhalation injury is carbon monoxide (CO) poisoning. NOTE: Doc said always recall the key points. Bulk of his Diagnosis: A nity of CO for hemoglobin is 200-250x > oxygen questions will come from there Clear odorless gas Respiratory Involvement Carboxyhemoglobin decreases the levels of normal Schwartz: Inhalation injuries are commonly seen in tandem oxygenated hemoglobin and can quickly lead to with burn injuries and are known to increase mortality in Anoxia and Death burned patients. Unexpected neurologic or cardiac symptoms should Inhalation injuries: raise the level of suspicion, and arterial Increase mortality carboxyhemoglobin level must be obtained because ○ Burns + inhalation injury + pneumonia = pulse oximetry can be falsely elevated. 60% increase Administration of 100% normobaric oxygen is the ○ Smoke inhalation is present in 35% of gold standard for treating CO poisoning and reduces hospitalized burn patients the half-life of CO from 250 minutes in room air to 40 ○ With associated ARDS + 60% TBSA = 100% to 60 minutes. mortality HYDROGEN CYANIDE TOXICITY Mortality is equivalent to Age + TBSA Diagnosis: Persistent Lactic Acidosis or ST elevation on E.g. Burn patient of 90%, Mortality is also 90% (dati Electrocardiogram yan, now it's 70%) Cyanide inhibits Cytochrome Oxidase which blocks Summary of Mortality in Schwartz: Smoke inhalation cellular oxygenation (35%), Inhalation Injury (25% increasing to 50% in Schwartz: Classic signs of cyanide patients with >20% TBSA burns), Pneumonia with poisoning—including bitter almond breath and cherry- inhalation injury (3x higher than those without red skin changes—are rare and should not be used as inhalation injury) the sole diagnostic criteria. Treatment: Sodium Thiosulfate - transforms cyanide Three stages of presentation into Nontoxic Thiocyanate derivative Stay hydrated & study well! © MED TRANS  SURGERY A LECTURE | DR. BRICCIO ALCANTARA 5 ○ Hydroxocobalamin (Vit. B12) - quickly SPECIAL EFFECTS OF ELECTRICAL INJURY complexes with Cyanide and is excreted by the 1. Cardiopulmonary Kidney Anoxia and Ventricular Fibrillation may cause ○ 100% Oxygen immediate death Early and Delayed rhythm abnormalities can Treatment of Burn occur Intubation ECG changes may occur some time after the A. Absolute indication for Intubation: burn in a delayed fashion a. Burned palate, tongue, pharynx 2. Renal b. Edema of posterior pharynx, Stridor High-risk of renal failure due to Hemoglobin c. Burned vocal cords and Myoglobin deposits in Renal tubules B. Relative Requires higher urine flow (75cc/hr in adults) a. Hoarseness b. Face, neck, and mouth burns TREATMENT c. Sooty carbonaceous sputum Fluid Resuscitation d. P02 - 25% Urine output maintained at 75-100cc/hr f. Massive burns, Circumferential chest burn Fasciotomy/ Escharotomy for circumferential injury Wound care SCHWARTZ TREATMENT OF BURN WOUND NUTRITION SILVER SULFADIAZINE Caloric needs One of the most widely used in clinical practice Schwartz: Titrating caloric needs closely is important Silver sulfadiazine has a wide range of antimicrobial because overfeeding patients will lead to storage of activity, primarily as prophylaxis against burn wound fat instead of muscle anabolism. infections rather than treatment of existing infections. 1. Harris-Benedict Equation Benefits: Inexpensive, easily applied, soothing qualities Calculates caloric needs using factors such as Cons: Neutropenia, allergic reactions (rare), retard gender, age, height, and weight epithelial migration in healing partial thickness wounds, May be inaccurate in burns of