13 - Anesthesia Complications

Complications of Anesthesia

▪ Respiratory Complications

▪ Circulatory Complications

▪ Allergic Reactions

▪ Nerve injury

▪ Malignant Hyperthermia

Hypoxemia Aseessment and Treatment

Assessed by

• pulse ox

• ABG

• colour

Treatment

• PEEP

• increase FiO2

Coughing

▪ Adequate anesthesia will prevent coughing

▪ Clear secretions via suctioning to reduce chance of aspiration

Breath Holding

▪ Usually during inhalation induction only

▪ Temporary

▪ Disappear as anesthesia deepens

Airway Obstruction

• Common in unconscious patient

  • Tongue falls back against posterior

• Treatment

  • repositioning

  • use oral or nasal airway

  • intubation

• Use armoured/reinforced ETT for prone patients to prevent kinking of tube

Laryngospasm

• Vocal cords clamp shut creating stridor, obstruction, and low or absent gas flow

▪ Caused by irritation of the airway during light anesthesia

▪ Can be a problem in spontaneously breathing, non-intubated patient

Treatment

• may use CPAP

• deepening anestheia

• intubation

Bronchospasm

• susceptible patients should be pretreated with bronchodilators

Treatment

• bronchodilators

• volatile anesthetic

• Epinephrine

Hypoventilation

• Caused by CNS depression or inadequate recovery from muscle relaxants

• Lead to hypercapnia and hypoxemia

• alterted by end tidal CO2

Treatment

• increase ventilation mechanically or manually

• treat the cause

  • lighten anesthesia

  • administer muscle relaxant agents

Barotrauma

• can lead to pneumothorax

• caused by high airway pressures

  • high volumes

  • use O2 flush (35-75LPM)

  • poor lung conditions

  • surgical procedures and positions

• treat the cause

Aspiration

• if aspirate is acidic (pH 2.5)

  • can cause bronchospasm, tracheal damage

  • increase RR, HR, crackles and wheezes

  • chemical pneumonsiitis

    • can be seen on X-ray in 12 to 24 hours

  • can lead to ARDS

• If aspirate is solid

  • can cause blockage and ateletasis distal to blockage

Aspiration

• prevention

  • which method of induction - RSI

  • surgery may be delayed, if possible to allow stomach to empty and/or the use of agents to reduce acidity

• Treatment

  • intubation and suction

  • ventilate with PEEP

  • antibiotics

  • remove foreign bodies with rigid brochoscope

hypotension cause

• induction often causes a 10 - 15% reduction in BP healthy patients

• Hypovolemia from surgical blood loss

• Decreased venous return resulting from ventilation or surgery

• Cardiovascular diseases may accentuate this

Hypotension tx

any fall in Bp > 20% is an emergency

Treatment

• Give 100% oxygen to ensure oxygen delivery while the cause is being diagnosed and corrected

• Fluid or blood replacement

• Inotropes

• Patient positioning?

• Lighten anesthesia

• Reduce airway pressures to improve venous return

• Release tension pneumothorax

Hypertension + Tx and causes

• pre-existing hypertension should be optimized prior to surgical procedure

• causes and treatment

Surgical stimuli – deepen anesthesia

• Hypercapnia & hypoxemia – optimize ventilation and oxygenation

• Fluid overload – diuretics (ex. Lasix)

• Drugs that ↓SVR and ↓BP can be used but with caution (do not want to overshoot and cause hypotension)

Arrhythmia

Causes

• Pre-existing heart disease

• Surgical procedures – manipulation of the patient

• Anesthetic agents

Sinus tachycardia

• usually benign

• from side effect of medications

Bradycardia

• ↓ HR is expected in anesthesia

• If profound may be treated with Atropine

Atrial flutter & Atrial fibrillation

• adenosin

• may require cardioversion

Premature ventricular contrations (PVC)

• caused by hypercapnia and the use of halothane

• lidocaine drip will reduce cardiac irritability

Air Embolism

• certain cerebral procedures and cardiopulmonary bypass can result in air being introduced into blood vessels

Air embolus may increase in size

• dangerous if nitrious oxide, diffuses into closed air spaces is used

Treatment:

• 100% Oxygen

• patient positioning

Allergic reactions

• Identify pre-existing allergies

• Anaphylaxis - most severe form

Signs

• Hives, dyspnea, hypotension, wheezing

  laryngeal/pulmonary edema, ↑ airway pressure, shock

Allergic Treatment

IV bolus of antihistamine (Benadryl)

Epinephrine

Bronchodilators

Steroids

Circulatory support

Nerve Injury

• Any peripheral nerve can be damaged through

  stretching or compression

• Anesthetized and/or paralyzed patients do not perceive pain and lack protective muscle tone

• avoid extreme position of head and arm

• ensure pressure areas are properly padded

• Muscle palsy from nerve injury may require long

  term physiotherapy

Malignant Hyperthermia (MH)

• Life threatening hypermetabolic disorder of skeletal muscle

▪ Incidence of 1 in 10,000

▪ Run in the family

Diagnosis of MH

▪ No signs are noted until it presents fully

▪ Molecular genetic testing – low sensitivity

▪ Muscle biopsy test (gold standard)

• Challenged with caffeine and halothane to observe for in vitro

hyper-reactivity

Warning Signs of MH

▪ Hypercapnia

▪ Tachycardia

▪ Arrhythmias

▪ Unstable or increasing blood pressure

▪ ↑ RR

▪ Hypoxia

▪ ↑ muscle rigidity

▪ Combined acidosis

▪ Dark brown urine

▪ Severe ↑ in body temp – may be delayed

MH Crisis Trigger

• ALL volatile anesthetics

• succinylcholine

Prevention of MH

• always inquire about patient’s anesthetics history and family’s anesthetic history

• avoid all triggers

• only use AGM that has never had volatile anaesthetics or has been purged with 100% O2

Treatment MH

• Call for help

• Remove triggers

• Hyperventilate with 100% oxygen

MH Treatment Dantrolene

• Decrease the excitation/contraction mechanism in

muscle and decreased intracellular calcium

• Mix with 60 mL sterile water

• Administer 2.5 mg/kg via IV bolus

• Repeat until stable or 10 mg/kg maximum reached

• Continue treatment 1-2 mg/kg every 6 hours for 24-48

hours

▪ Treat acidosis with sodium bicarbonate

▪ Cool body temperature

Airway Obstruction/ Laryngeal spasms

• Tongue failing back

  • Use masal airway

  • put pt in sititing or lateral position

  • head tild/chin lift or jaw thrust

• Laryngospasm

  • Suction to remove irritants

  • CPAP

  • Re-intubate

Hypoventilation: Pain splingting

• Splinting of chest or abdomen wounds often leads to hypoventilation

▪ Compounded by opioid analgesics

▪ Reverse with naloxone/narcan if necessary

Hypoventilation :Muscle Relaxants

With non-depolarizing muscle relaxant

▪ Reverse with neostigmine, also give atropine or gylcopurate because neostigmine drops HR

▪ If hypoventilation persists, re-intubation and ventilation support may be necessary

With depolarizing muscle relaxant

▪ Airway management will be needed

Hypoxemia

• increase FiO2

• Treatment causes:

  • Airway obstruction

  • Hypoventilation

  • Nitrous oxide washout

  • Pulmonary edema may require diuretics and inotropes along with O2

  • Large V/Q mismatch would suggest bronchial hygiene and/or lung recruitment protocols

BP Abnormalities

Check patient’s baseline

Treat the cause(s):

▪ Hypertension

• Hypercapnia and hypoxemia

• Full bladder

• Fluid overload

▪ Hypotension

• Hypovolemia

• Opioid analgesics given for pain

Nausea and Vomiting

• normal side effect of:

  • Opioids

  • Abdominal and eye surgical procedures

  • Upper airway procedures – swallowed blood

  • Air in stomach

▪ Better prevented than treated

▪ Put patient in sitting or lateral position to reduce risk of aspiration

Shivering

• very common in recovery

• causes large increase in O2 demand, which requires similar increase in alveolar ventilation and cardiac output

• patients recovering from anesthesia may not be able to cope with these high demands and become hypoxic

• keep patient warm with blankets

• give oxygen

Restlessness + Tx

• Severity ranges from mild discomfort to full psychomotor disturbances requiring restraints

• Treat the causes

  • discomformt from prolonged position

  • pain

  • full bladder

  • ketamine

    • recover patient ina room with little stimulation

    • adminiter Midazolam IV to prevent unpleasant dreams assocaited with ketamine

if pain is uncontrolled (or unrelive) it can cause many complications like

• lengthen the hospital stay

• prolonged wound healing

• severe negative outcomes

Pain due to splinting of wounds

• hypoventialtion

• retained secretions

• atelectasis

• V/Q mismatch

• hypoxemia

• pneumonia

• respiratory failure

Pain cause by hypotension & tachycardia

• myocardial ischemia

• heart failure

Limited mobility pain

increase risk of deep vein thrombosis (DVTs)

Pain Management

• Treat anxiety

• avoid restrictive bandages

• elevated operated extremity above the heart level to minimize swelling

• have large “coughing” pillow to stablize abdomen or chest during coughing, sneezing, or deep breathing exercise

• analegics

Patient- controlled analgesia (PCA)

• allow patient to titrate a small bolus of analgesics via pump by activating a button

• require oriented patient with IV or epidural access

PCA Modes

• PCA only

• PCA + continuous background infusion

Limits to PCA

• maximum dose limit

• lockout interval

Advantages of PCA

• rapid onset - intravascular

• maintain plasma concentration in a narrow analgesic range

• eliminate nursing delays in giving IV boluses

• accommodate patient’s changing needs

• patients benefits psychologically

Multimodal pharmacotherapy

• Acetaminophen

• NSAIDs

• Gabapentinoids

• local anesthetics

  • topic

  • local infiltrations

  • neuraxial

Neuraxial

• epidural catheter

• pain free with ambulatory ability

• improve postoperative pulmonary function

• faster recovery