•  Consider bronchoscopy

•  Consider bag ventilation

•  Treat underlying problem

BRONCHOSPASM

Causes

•  Preexisting reactive airway disease (asthma)

•  Manipulation of upper airway (oral endoscopy)

•  ETT with inadequate anesthesia

•  ETT causing carinal or bronchial stimulation (endobronchial intubation)

•  Excessive histamine release (morphine, atracurium) or β-blockade

•  Anaphylaxis

•  Pulmonary edema

Investigations

•  Examine ETT for patency (secretions, kinks) & proper position

•  Examine for wheezing, air movement

•  Capnograph → shows expiratory upsloping

•  High peak airway pressures, hypoxia & hypercarbia

•  Rule out: Pneumothorax, pulmonary embolus, & pulmonary edema

Management

•  ↑ FiO₂

•  ↑ Anesthetic depth (inhalational agents are bronchodilators)

•  ↑ Expiratory time, ↓ RR as this helps decrease gas trapping

•  Give nebulized albuterol via ETT (not effective in severe bronchospasm/lost airway)

•  Epinephrine IV/SC (esp for anaphylaxis) → titrate to effect

•  Aminophylline (2nd line treatment—6 mg/kg bolus, then 0.5 mg/kg/hr)

•  Hydrocortisone (long term)

HYPOTENSION

MAP <60 mm Hg or 20–25% reduction from baseline

Differential Diagnosis

•  Decreased preload

• ↓ Blood volume (hemorrhage, inadequate fluid replacement, third spacing)

• ↓ Venous return (change in pt position, i.e., Trendelenburg)

• Pericardial tamponade, pneumothorax, surgical compression of venous structures, pneumoperitoneum from laparoscopy, excessive PEEP

•  Decreased afterload

• Sepsis, vasodilating drugs (anesthetics), anaphylactic reaction neurologic injury

•  Decreased contractility

• MI, arrhythmias, CHF, anesthetic effect, electrolyte imbalances

Investigations

•  Examine BP cuff for fit

•  Examine preoperative BP trends

•  Calculate fluid balance (including blood loss)

•  Ensure that the IV site is intact & not infiltrated

•  Examine arterial line waveform for respiratory variation

Treatment Options

•  Administer fluid bolus

•  ↓ Anesthetic agents

•  Administer vasopressors (phenylephrine 40–100 mcg/ephedrine 5–10 mg)

•  Administer other vasoactives/inotropes (norepinephrine, dobutamine, milrinone, dopamine)

•  Consider invasive monitoring (CVP, arterial line, PA catheter, echocardiogram)

HYPERTENSION

BP >140/90 mm Hg or MAP >20–25% baseline value

Differential Diagnosis

•  Primary HTN

• HTN with no known cause (70–95% of hypertension)

•  Secondary HTN

• Pain/surgical stimuli (inadequate anesthesia, tourniquet pain), ETT stimulation, bladder distention

• Hypercarbia, hypoxia, hypervolemia, hyperthermia

• Intracranial pathology (↑ ICP, herniation, hemorrhage)

• Endocrine problems (pheochromocytoma, Cushing syndrome, hyperthyroidism, hyperparathyroidism)

• Alcohol withdrawal

• Malignant hyperthermia

• Inadvertent vasoactive drug administration

• Antihypertensive medication withdrawal

•  Consider timing of HTN with case events:

→ HTN prior to induction

Withdrawal from antihypertensive medications, essential hypertension, pain

→ HTN postinduction

Laryngoscopy effect, improper ETT placement, hypercarbia from esophageal intubation, misplacement of gastrostomy tube into trachea, pain, hypoxia

→ HTN during the case

Inadequate pain control, hypercarbia, pneumoperitoneum, fluid overload, drugs (vasopressors), bladder distention, tourniquet pain

Investigations/Treatment Options

•  Examine BP cuff size & placement, arterial line waveform

•  Review anesthetic/surgical events of the case

•  Check for hypoxia/hypercarbia

•  Check vaporizer agent level

•  Administer antihypertensives (β-blockers/vasodilators)

HYPERCARBIA

↑ CO₂ levels (as measured by blood gas or end-tidal gas analysis) (normal values 38–42 mm Hg)

Differential Diagnosis

•  ↑ CO₂ production

• Malignant hyperthermia

• Sepsis

• Fever/shivering

• Thyrotoxicosis

•  ↓ CO₂ elimination

• Reduced minute ventilation

Altered lung mechanics (atelectasis, pneumoperitoneum with CO₂, surgical retractors preventing lung expansion)

Airway obstruction (secretions, mucous plugging)

Inadequate ventilator settings (↓ volumes, ↓ fresh gas flows)

Oversedation

• Increased dead space

ETT malfunction (kinks, endobronchial intubation)

Exhausted CO₂ absorber

• Drug effects (muscle relaxants/narcotics/benzodiazepines)

•  Consider timing of ↑ CO₂ with case events:

→ ↑ CO₂ at the start of a case

• Improper ETT placement, inadequate ventilator settings, oversedation of spontaneously breathing pt

→ ↑ CO₂ postinduction/during case

• MH, neuroleptic malignant syndrome (NMS), improper vent settings, thyrotoxicosis, release of tourniquet, exhausted CO₂ absorber

→ ↑ CO₂ during emergence

• Inadequate reversal of muscle relaxants, residual narcotic/anesthetic effects, neurologic causes, electrolyte disturbances, hypoglycemia

Investigations/Treatment Options

•  Examine pulse oximeter

•  Ensure appropriate ventilator settings

•  Examine CO₂ absorber for exhaustion

•  Consider ABG

•  If spontaneously breathing: Assist breathing, lighten sedation

•  If mechanically ventilated: Increase minute ventilation

HYPOCARBIA

↓ CO₂ levels (as measured by blood gas or end-tidal gas analysis)

Differential Diagnosis

•  Hyperventilation

•  ↓ Metabolic rate (hypothermia, hypothyroidism)

•  Pulmonary embolism

•  Air embolus

•  Cardiac arrest (hypoperfusion)

•  ETT dislodgement/circuit disconnect

Investigations/Treatment Options

•  Check breathing circuit

•  Check blood pressure, heart rate, SpO₂

•  Check/modify ventilator settings

•  Treat underlying cause

↑ PEAK AIRWAY PRESSURES

Differential Diagnosis

•  Circuit problem (stuck valve, PEEP valve on wrong, kinked hose)

•  ETT problem (kinked/bitten, plugged with mucus, bad positioning)

•  Drug induced (opiate chest wall rigidity, inadequate paralysis/anesthesia, MH)

•  ↓ Pulmonary compliance (asthma, insufflation, pneumothorax, aspiration)

Treatment

•  Check tubes, hand ventilate, 100% FiO₂

•  Listen to lungs, suction ETT, add bite block, consider paralysis

OLIGURIA

Urine production <0.5 mL/kg/hr (also see Chapter 22, Renal System)

Differential Diagnosis

•  Prerenal: Intravascular fluid depletion

•  Renal origin: Lack of renal perfusion (hypotension, cross clamping, renal artery stenosis), intrinsic renal damage (nephrotoxic drugs/vasculitis)

•  Postrenal: Ureteral obstruction/disruption, obstruction of Foley catheter

Investigations/Treatment Options

•  Examine vital sign monitors to establish hemodynamic stability

•  Examine/irrigate Foley catheter for obstruction/improper placement

•  Review possible nephrotoxic drugs & withdraw

•  Examine fluid administration/blood loss/surgical manipulation

•  Consider fluid challenge to treat prerenal oliguria

•  Treat underlying cause

MYOCARDIAL ISCHEMIA/INFARCTION

Damage to heart muscle from imbalance between myocardial O₂ supply & demand

Etiology

•  Atherosclerosis (accounts for 90% of MIs)

•  Coronary aneurysms

•  Coronary artery spasm

•  O₂ demand outweighs supply (e.g., aortic stenosis)

•  Blood viscosity changes (polycythemia)

•  Embolic sources (endocarditic vegetations)

Investigations

•  Lead II—best for arrhythmia detection (RCA association & nodal system)

•  Lead V5—best for ischemia detection (LAD & anterior/lateral areas of heart)

•  Both lead II & V5 will detect >90% of ischemic events

•  ST-segment depression ≥0.1 mV

(usually subendocardial pattern → due to partially obstructed coronary)

•  ST-segment elevation ≥0.2 mV

(usually transmural pattern → due to thrombosed coronary)

•  T-wave inversions & Q-waves

•  Dysrhythmias

•  Hypotension

•  TEE (most sensitive method for determining early ischemia)

•  CK, CK-MB, troponins, cardiac consult (for possible coronary intervention)

Treatment Options

Goal: Maintain acceptable balance of myocardial O₂ supply & demand (Note: If ↑ afterload, preload, contractility, & heart rate → ↑ myocardial O₂ demand)

•  Maintain BP within 20% of preoperative levels

•  Confirm correct placement of ECG leads, consider 5- or 12-lead ECG

•  Notify surgeon of ischemia & coordinate completion of surgical procedure

•  Place patient on 100% FiO₂ & ensure adequate ventilation

•  Consider reducing anesthetic agents

•  Consider β-blocker administration if tachycardic

•  Evaluate BP stability & consider invasive monitoring (arterial line/CVP/PA)

•  If hypotensive with ischemic ECG changes ↑ BP with pressors to ↑ myocardial perfusion pressure

•  Consider fluid therapy & inotropic agents to support myocardial contractility

•  Consider anticoagulation (aspirin, heparin)

•  Obtain intraoperative cardiology consult to coordinate care

MALIGNANT HYPERTHERMIA (SEE APPENDIX C)

•  Definition: Inherited syndrome of skeletal hypermetabolism after exposure to a triggering agent

•  Mechanism: ↓ reuptake of ionized Ca²⁺ by sarcoplasmic reticulum

→ Intracellular Ca²⁺ accumulation/potentiation of muscle contraction

→ ↑ Aerobic/anaerobic metabolism

•  Triggering drugs: Succinylcholine, potent volatile agents (sevoflurane, desflurane, isoflurane)

•  Nontriggering drugs: N₂O, narcotics, local anesthetics, nondepolarizing muscle relaxants (cisatracurium, vecuronium, rocuronium), IV induction agents (propofol, ketamine, etomidate, barbiturates)

•  Prevention: For MH-susceptible patients, use a “clean” machine (remove vaporizers, change CO₂ absorber, flush with high flow O₂ for 20 min)

Differential Diagnosis

•  Neuroleptic malignant syndrome (NMS)

•  Thyrotoxicosis

•  MAOI reactions

•  Pheochromocytoma

•  Inaccurate end-tidal CO₂ monitoring

Clinical Presentation/Investigation

•  Can occur anytime during an anesthetic & postoperatively (up to 24 hrs)

•  Early signs: ↑ end-tidal CO₂ levels despite adjustment of ventilation, tachycardia

•  Late signs: ↑ temp, rhabdomyolysis & myoglobinuria, metabolic & respiratory acidosis, rigidity, dysrhythmias, HTN, cardiac arrest, masseter spasm, hypoxemia, hyperkalemia

•  Lab testing: ABG (check for acidemia, elevated CK, myoglobinuria, elevated K⁺) ↑ difference in mixed venous CO₂ & arterial CO₂

Treatment

•  Call for help & notify surgeon

•  Discontinue triggering agents

•  Hyperventilate with 100% FiO₂

•  Administer dantrolene (2.5 mg/kg IV)

→ Repeat dantrolene until MH controlled (up to 10 mg/kg IV)

→ May need to administer for up to 72 hrs after episode

•  Monitor ABG, vital signs, serum CK

•  Treat acidemia with sodium bicarbonate

•  Cool patient with IV fluids, cold water lavage in stomach & bladder to temp <38°C

•  Treat arrhythmias & promote renal function with fluids/mannitol/furosemide

•  Contact Malignant Hyperthermia Hotline as needed: 800–644-9737

BRADYCARDIA

Heart rate <60 bpm

Differential Diagnosis

•  Altered impulse formation (↑ vagal tone or ↓ SA node automaticity)

•  Pharmacologic agents (β-blockers, Ca-channel blockers, cholinergics, narcotics, anticholinesterases, α₂-agonists)

•  Pathologic causes (hypothermia, hypothyroidism, sick sinus syndrome, hypoxemia)

•  Myocardial ischemia

•  Surgical/anesthesia stimuli (traction on eye, neuraxial anesthesia, laryngoscopy)

• Reflex bradycardia

Investigations/Treatment

•  Confirm correct ECG lead placement

•  Check vital signs for hemodynamic stability

→ If stable, consider anticholinergics/ephedrine

→ If unstable, ↑ FiO₂ to 100%, abort anesthetic, administer epinephrine/atropine/CPR, consider placement of pacing device

•  Treat underlying cause

TACHYCARDIA

Heart rate >100 bpm

Differential Diagnosis

Tachycardia + Hypertension

•  Pain/light anesthesia/anxiety

•  Hypovolemia, hypercapnia, hypoxia, acidosis

•  Drugs: Vagolytic drugs (pancuronium, meperidine), ketamine, ephedrine, epinephrine, anticholinergic drugs (atropine/glycopyrrolate), desflurane, isoflurane, β-agonists, vasodilators → reflexive tachycardia (hydralazine), caffeine

•  Electrolyte abnormalities: Hypomagnesemia, hypokalemia, hypoglycemia

•  Myocardial ischemia

•  Endocrine abnormalities: Pheochromocytoma, hyperthyroidism, carcinoid, adrenal crisis

•  Bladder distension

Tachycardia + Hypotension

•  Anemia

•  Congestive heart failure

•  Valvular heart disease

•  Pneumothorax

•  Immune-mediated problems (anaphylaxis, transfusion reactions)

•  Myocardial ischemia

•  Sepsis

•  Pulmonary embolism

Treatment Options

•  Ensure adequate oxygenation and ventilation

•  Verify ECG leads’ placement

•  Assess BP & prepare to treat depending on scenario

•  Consider arterial line placement

•  Assess volume status if hypotension exists and treat accordingly

•  Assess depth of anesthesia

•  Treat underlying cause

DELAYED EMERGENCE

Differential Diagnosis

•  Residual drug effects (volatile agents, narcotics, muscle relaxants)

•  Neurologic complications (seizure with postictal state, CVA, infection, tumor effect)

•  Metabolic (electrolyte abnormalities, hypoglycemia, hyperglycemia, adrenal failure)

•  Respiratory failure (due to hypercarbia/hypoxia)

•  Cardiovascular collapse

•  Hypothermia

•  Sepsis

Investigations/Treatment Options

•  Check for residual neuromuscular paralysis with train of four monitor and ensure that muscle relaxants have been reversed

•  Ensure hypoxia & hypercarbia do not exist (check arterial blood gas)

•  Check glucose/electrolytes & replace accordingly (rule out hypoglycemia and hypo/hypernatremia

•  Consider narcotic reversal with Naloxone 40 mcg IV and repeat every 2 min up to 0.2 mg

•  Consider benzodiazepine reversal with Flumazenil 0.2 mg IV every 1 min up to 1 mg

•  Check for hypothermia and warm if body temperature is less than 34°C

•  Consider neurologic imaging if neurologic examination warrants

•  Supportive care

ANAPHYLAXIS

Severe type 1 hypersensitivity allergic reaction (IgE) with degranulation of mast cells/basophils

Differential Diagnosis

•  Anaphylactoid—not IgE-mediated, no prior sensitization to antigen required

•  Vasovagal reactions generalized urticaria/angioedema, asthma exacerbations

•  Myocardial infarction, stroke

Clinical Manifestations

•  Cardiovascular collapse, tachycardia, dysrhythmias

•  Bronchospasm, pulmonary & laryngeal edema, hypoxemia

•  Rash, skin flushing, peripheral/facial edema

Treatment Options

•  Remove stimulus (if known)

•  Oxygen, consider intubation

•  Give volume if hypotensive

•  Hydrocortisone 250 mg to 1.0 g IV or methylprednisolone 1–2 g IV

•  For rapidly decompensating situations give Epinephrine 20–100 mcg IV bolus followed by infusion if necessary (can give 0.5–1.0 mg IV for cardiovascular collapse)

•  Diphenhydramine 50 mg IV/ranitidine 50 mg IV

•  Norepinephrine 4–8 mcg/min

•  Sodium bicarbonate 0.5–1 mEq/kg for persistent acidosis

•  Consider intubation (if pt not intubated)

•  Evaluate airway for edema prior to extubation

Prevention

•  Premedicate with diphenhydramine (H₁-blocker), ranitidine (H₂-blocker), prednisone

LATEX ALLERGY

Incidence/Risk Factors

•  Pts with spina bifida & congenital genitourinary abnormalities

•  Health-care workers (housekeepers, lab workers, dentists, nurses, physicians)

•  Rubber industry workers

•  Atopic patients (asthma, rhinitis, eczema)

•  Pts who have have undergone multiple procedures

Mechanism

•  IgE-mediated immune response

Preoperative Evaluation

•  No routine diagnostic testing indicated (RAST & skin tests used occasionally)

Equipment/Drug Considerations

•  Routine preop administration of H₁– & H₂-blockers not usually recommended

Anesthetic Considerations

•  Avoid products that may contain latex (gloves, tourniquets, blood pressure cuffs, face masks, ETT tubes, PA catheters, IV tubing with latex injection ports, rubber stoppers in medication vials)

•  Notify entire OR team (nurses, surgeon) & place large sign on OR door

Treatment

•  Latex reaction may present as anaphylaxis (>20 min after exposure)

•  Symptoms include hypotension, bronchospasm, rash

•  Treatment similar to anaphylaxis treatment (see above) (remove offending agent, give 100% O₂, fluid resuscitation, epinephrine, corticosteroids, diphenhydramine, aminophylline)

GASTRIC ACID ASPIRATION OR VOMITING UPON INDUCTION OF ANESTHESIA

•  Can cause chemical pneumonitis

Clinical Manifestations

•  Early signs: Coughing, shortness of breath, wheezing, hypoxia, & cyanosis

•  Late signs: Fever, metabolic acidosis, RML & RLL infiltrate on CXR

Management

•  If possible, place patient in head-down position

•  Turn the patients head to the side if actively vomiting while unconscious and aggressively suction

•  Administer 100% O₂

•  Consider placement of a suction catheter into the trachea to remove large particulate matter

•  Perform rigid bronchoscopy (but no lavage)

•  Obtain chest x-ray

•  Antibiotics (staph, pseudomonas coverage) & steroids generally not recommended

COMPLICATIONS OF LARYNGOSCOPY AND INTUBATION

Causes

• Inexperienced use of laryngoscope

• Difficulty placing ETT

• Poor existing dentition

General complications

• Physiologic stimulation, hypercarbia, hypoxia, dental damage (#1 cause of malpractice claims)

• Airway trauma, vocal cord paralysis, arytenoid dislocation, ulceration/edema of glottic mucosa

• Tube malfunction and/or malposition

Specific complications

• Postintubation croup in children secondary to tracheal/laryngeal edema

• Recurrent laryngeal nerve damage from ETT cuff compression → vocal cord paralysis

• Laryngospasm from stimulation of superior laryngeal nerve

• Involuntary/uncontrolled muscular contraction of laryngeal cords

• Caused by pharyngeal secretions or direct stimulation of ETT during extubation

• Treatment: (1) gentle positive pressure ventilation, (2) succinylcholine (0.25–1 mg/kg to relax laryngeal muscles)

• Negative-pressure pulmonary edema

• Can occur during strong inspiratory effort caused by large negative intrathoracic pressure gradient against closed vocal cords

• Prevention: Place bite block prior to emergence

• Treatment: Maintain airway, provide O₂, consider PEEP/reintubation