Burns And ANAESTHESIA

DR.MUHAMMED MUHSEN AHMED DAMUDI

SOHAR HOSPITAL.

ANESTHESIA and BURNS

DR.MUHAMMED MUHSEN AHMED DAMUDI

SOHAR HOSPITAL.

Burns : are tissue injuries resulting from direct contact with flames, hot liquids, gases, caustic chemicals; electricity; or radiation

high risk groups for severe burn injuries:The very youngThe very oldThe very careless

3rd largest cause of accidental death 50% of adults <45 yr. survive 75% burns

Introduction

According to a 2002 report of the American Burn Association, more than 1.1 million persons in the United States sustain burns each year, of whom more than 50,000 are hospitalized and 4,500 die

cont … Introduction

Largest body organ. 15% of body weight ,It is not a passive organ.Protects underlying tissues from injuryTemperature regulationActs as water tight seal, keeping body fluids

inSensory organ

Injuries to skin which result in problems like:InfectionInability to maintain normal water balanceInability to maintain body temperature

Anatomy & Physiology of the Skin

Two layersEpidermisDermis

EpidermisOuter cells are deadAct as protection

and tight sealonly the epidermis is

capable of true regeneration

Anatomy & Physiology of the Skin cont…

Thermal (heat) burnsChemical burnsElectrical burnsInhalational burns

Types of Burns

Depth Classification :SuperficialPartial thickness

Superficial Deep

Full thicknessDegree Classification :

FirstSecondThirdforth

Thermal (heat) burns

Thermal (heat) burns cont.…

Superficial Burn:1st Degree BurnSigns & Symptoms

Erythema Pain at burn siteInvolves only epidermisabsence of blistersHeals within 3 to 6 daysExample - sunburn

Partial-Thickness Burn: 2nd Degree Burn

Signs & Symptoms• Entire epidermal layer• Part of underlying dermis• Mottled and red, painful

• swelling and blisters• Healing in 10 to 21 days• Not enough to interfere with

regeneration of the epithelium


Full-Thickness Burn: 3rd Degree BurnSigns & Symptoms

• Destruction of all epidermal and dermal elements

• Burn into subcutaneous fat or deeper• Skin is charred and leathery (woody)• Generally not painful (nerve endings are dead)



Fourth-degree• Full-thickness• Extending into muscle, tendons or

bones• Black and dry• No pain• Eschar formation

It is a critical aspect of the initial evaluation of burned patients in the emergency department.

It will determine whether transfer to a specialized burn center is required as well as the magnitude of initial fluid resuscitation and nutritional requirements

Small areas: palm of patient's hand equals 1% of BSA

Large areas: “rule of nines”: Regions of the body approximating 9% BSA or multiples

Estimation of Burned Area

infants and babies have a proportionally greater percentage of BSA in the head and neck region and less in the lower extremities than adults

Electricity is generated by the flow of electrons across a potential gradient from high to low concentration through a conductive material

EB:- depends upon:what tissue current passes throughwidth or extent of the current pathwayduration of current contact

Most damage done is due to heat produced as current flows through tissues

True extent of the damage is often hidden= nerve blood, muscle, skin, tendon, fat, bone best worst conductorsBurns are often most severe at the source and ground

contact points

Electrical Burns

Complication :

Cvs : asystole , (VF) , conduction abnormalities and direct trauma to cardiac muscle fibers. Survivors of electrical shock can experience subsequent arrhythmia, usually sinus tachycardia and premature ventricular contractions (PVCs).

Respiratory: Chest wall muscle paralysis from tetanic contraction may cause respiratory arrest if the current pathway is over the thorax. Injury to the respiratory control center of the brain can also cause respiratory arrest. The lungs are a poor conductor of electricity and generally are not as susceptible to direct injury from current as tissues with lower resistanc

Electrical Burns

CNS :Most acute CNS or spinal deficits resulting from electrical injuries are due to secondary blunt trauma or burns. Often, the patient has transient confusion, amnesia, and impaired recall of events if not frank loss of consciousness

long-term neurologic complications include seizures, peripheral nerve damage, delayed spinal cord syndromes, and psychiatric problems from depression to aggressive behavior.

Electrical Burns

Musculoskeletal: Acute injuries include fracture from blunt trauma and compartment syndrome from burnsMassive muscle damage can cause severe

rhabdomyolysis and subsequent renal failure.

ENT/head: The head is a common point of entry for high-voltage injuries. Patients may have perforated tympanic membranes, facial burn, and cervical spine injury. Approximately 6% of victims develop cataracts,

Electrical Burns

http://emedicine.medscape.com/article/827738-overview

Most acids produce a coagulation necrosis by denaturing proteins, forming eschar that limits the penetration of the acid.

Bases typically produce a more severe injury known as liquefaction necrosis.

Damage continues until the substance is removed or neutralized

Chemical burn

Inhalation injury is the main cause of death in burn patients

Its results from the airway inflammatory response to inhalation of the products of incomplete combustion and is the leading cause of death (up to 77%) in burn patients

Usually limited to upper airways Injury to lower airways be considered when:

Overwhelming heat exposure Inhalation of steam Aspiration of hot liquids direct

pulmonary injury

Inhalational injury

cont… Inhalational injury

Effects of of Acute Smoke Inhalation InjuryImpairment of mucociliary function infectionMucus hypersecretionTissue inflammation with tracheobronchiolitis,

bronchitis, laryngitis, pneumonitisEpithelial sloughingBiochemical alteration with surfactant

inactivationIncreases vascular permeability and lung

edemaBronchiconstrictionInitially large airway obstruction late small

and large airwaysCarbon Monoxide (CO) poising


Carbon Monoxide (CO) poisingMost dangerous gas in fire. Leading cause

of death at scene and 24h after fireOdorless, colorless gasCarbon monoxide's affinity for hemoglobin is

200 times greater than that of oxygenshift dissociation curve to left tissue hypoxiapulse oximeters using two wavelengths

cannot detect COHbnormal COHb < 1.5% in nonsmokers and <

10% in smokers


Administration of 100% oxygen will shorten the half-life of COHb from 4 h in room air to less than 1 h

Mild poisoning (COHb<20%) --- 100% non-rebreathing mask until level falls <5%

Moderate poisoning (COHb 20 – 40%) without cardiac or neurologic dysfunction --- monitoring of acid-base status and 100% oxygen until level falls <5%

Severe poisoning (COHb>40%) or with cardiac or neurologic symptoms--- hyperbaric oxygen therapy

Admission is required for all with level >25% or with cardiac and neurologic symptoms

treatment Carbon Monoxide (CO) poising

Airway and BreathingEarly intubation required to treat

causes of respiratory dysfunction:1. CO poisoning2. Upper airway edema3. Subglottic thermal and chemical burns

4. Chest wall restriction

ABC’s of burn resuscitation

Upper Airway Edema Most pronounced first 8 hrs. postburn

s&s Stridor ,Horseness ,Facial burns ,Singed nasal hair or

eyebrows Soot in sputum or oropharynx ,Respiratory distress

Treatment:Early intubation before edema makes it

impossibleHumidified O2 to help clear secretionsBronchodilators to manage bronchospasmElevate HOB 20-30 degrees

Decrease head and neck edema

Cont.. ABC’s of burn resuscitation

Chest Wall Restriction Found mostly with circumferential 3rd degree

burnsLoss of elasticity incr. work of breathing

required to maintain FRC and Vt.Symptoms may incr. 10-12 hrs postburn

secondary to maximum edema formationTreatment

Ventilation and mechanical ventilation

Escharotomies


Circulation Burn victims have incr. capillary permeability in all burned areas resulting in an intravascular fluid shift into interstitial spaceResults are:

HyponatremiaHypoprotienemiaInterstitial edema


Cardiovascular resuscitationFluid replacement

consists of crystalloid, usually Ringer's lactate, with or without the addition of colloid. Standard protocols for fluid replacement use body weight in kilograms and percent TBSA burned.

Parkland formula (4.0 mL of Ringer's lactate per kg per % TBSA burn per 24 hours


Fluid replacementBrooke formula: 1.5 mL of crystalloid per kg

per % TBSA burn per 24 hours plus 0.5 mL of colloid per kg per % TBSA burn per 24 hours plus 2,000 mL of 5% dextrose in water per 24 hours

Half the calculated fluid deficit is administered during the first 8 hours postburn and the remainder is administered over the next 16 hours.

The patient's daily maintenance fluid requirements are given concurrently


Fluid replacementThe endpoints of fluid therapy are hemodynamic stability and maintenance of an adequate urine output.

In extensive burns, fluid management is adjusted according to invasive monitors and laboratory studies


Decompression proceduresescharotomies & fasciotomies

Burn excision & skin grafting

Reconstruction operationsSupportive procedures

tracheostomy, gastrostomy, vascular access

Common Operation for burn’s pt

Preoperative :Burn injuries may result in a broad

spectrum of physiologic impairments. These vary, depending on the percent of TBSA burned, location of burns, age of the patient, time elapsed since initial injury, and interim treatment. Ideally, burn patients are fluid-resuscitated and stabilized before being brought to the OR

Anesthetic Considerations for burn pt

physiologic impairments :Respiratory :- Upper airway: A patient with burns around the airway (e.g., singed nose hairs) should be intubated as early as possible.

Direct inhalational injury and fluid resuscitation may make delayed intubation more difficult 2° upper airway edema.

Anesthetic Considerations for burn pt cont..

Respiratory Lower airway: Physiologic derangements may

include pulmonary edema and ARDS. Additionally, burn patients can be severely hypermetabolic (e.g., a patient with 40% TBSA burns may have twice the normal metabolic rate) with corresponding increased CO2 production. These patients may have high minute-ventilation requirements. Pressure control ventilation and high levels of PEEP may be useful.

Other possible effects of severe burns include: ↓ lung and chest-wall compliance, ↓FRC,, ↑ carboxyhemoglobinemia, and ↑ methemoglobinemia.


Cardiovascular : -Alterations in microvascular permeability result in a trans-capillary fluid flux and tissue edema 12-24 hours after thermal injury

Large amounts of water, electrolytes and proteins are lost into the extravacular space, leading to intravascular fluid depletion and hypovolemic shock (burn shock)

The hypermetabolism associated with burns increases cardiac demand, and burn patients have greatly elevated circulating levels of catecholamines →↑↑HR + ↑ CO

Major burns require 1.5-1.7 times the caloric need


Musculoskeletal :- Damaged muscle →↑ acetylcholine receptor density, resulting in ↓ sensitivity to nondepolarizing muscle relaxants and potentially fatal elevations of K+ in response to succinylcholine.

avoid succinylcholine after 24 h postburn and for at least 1 yr thereafter


Hematologic : Coagulopathies may result directly from the burn injury, as well as from rapid replacement of blood loss during operative procedures

IV access : May be difficult; assess preop. Consider central line placement with a large-bore catheter

Premedication : Patients are commonly placed on high-dose narcotics after the initial injury; additional narcotics are frequently required to provide adequate analgesia for transport and movement to the OR table.


Transport : For patients with severe ARDS, transportation from burn unit to OR may face challenges with regard to ventilation.

Cardiopulmonary monitoring must be continued during transport; the ventilation system used in transport must be capable of delivering high minute-volumes, PEEP, and inspiratory pressures.

These requirements may not be satisfied by standard bag-valve systems and may require a high-quality transport ventilator


Intraoperative : Anesthetic technique : GA , Regional techniques

are rarely feasible , LMAs are not recommended due to frequent repositioning of patient intraop

If the face is burned, awake FOI may be necessary securing the ETT may be difficult. Alternatives to

taping the ETT include suturing the tube to the teeth

Induction : If the patient is adequately volume-resuscitated :

propofol (1.5–2.5 mL/kg iv) or thiopental (3–5 mg/kg) may be used

If the patient is intravascularly volume-depleted etomidate (0.3 mg/kg) or ketamine (1–3 mg/kg) is

recommended


USE OF MUSCLE RELAXANT-!--Rapid sequence induction and intubation

Indicated for full stomach e.g. ileus

-!--Succinylcholine - contraindicated 24 hours to 2 years after major burns, S/E-----profound hyperkalemia and cardiac arrest.

-!--Rocuronium in dosage of 0.9 mg/kg

Can intubate in 45 sec

Must be confident of airway management-

!----Large doses of non-depolarizing muscle relaxants may be required due to altered protein binding and an increase extrajunctionalacetylcholine receptor which bind non-depolarizing drug without causing neuromuscular effect


Maintenance : Standard maintenance Physiologic derangements of the

respiratory system (ARDS, pulmonary edema) and a hypermetabolic state may require minute-volumes > 30 L/min, and high inspiratory pressures and PEEP, for adequate ventilation.

Intraop, surgeons may use epinephrine-soaked sponges to ↓ blood loss. Systemic absorption of epinephrine will cause tachycardia and increase the probability of dysrhythmias; therefore, it is best to avoid halothane or desflurane. Isoflurane and sevoflurane are acceptable.


Emergence :Estimation of an adequate dose of narcotic to

provide postop analgesia should be considered.

If large-volume resuscitation has occurred intraop, the possibility of clinically significant airway edema considered; use caution before extubating to ensure a patent airway.

Blood and fluid requirements : Blood must be in OR before induction. The major blood loss generally is associated with eschar excision, usually the first part of the procedure


Thermal considerations :Temperature must be monitored

throughout the caseWarm all fluids.

Humidify gases.Warming blanketReflective head cover

Monitoring :Standard monitors : ECG may require

needle electrodes if there is no skin availability to apply adhesive electrodes


Positioning : The burn patient may be uniquely susceptible

to laryngeal or upper airway edema in the prone position; therefore, examination of the upper airway before extubation is recommended to avoid emergent reintubation

PostoperativeComplications :

Hypothermia-use radiant heater or warming blanketsCoagulopathy : May occur as the result of massive

blood loss and replacementPain management : PCA - fentanyl or morphine

sulfate


RAMADAN MUBARAK

..

Health & Medicine

Burns And ANAESTHESIA