INTRAOPERATIVE PROBLEMS


•  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


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Aug 28, 2016 | Posted by in ANESTHESIA | Comments Off on INTRAOPERATIVE PROBLEMS

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