Exam 2 study guide Flashcards
What neurotransmitters are involved in wakefulness
acetylcholine, dopamine, norepinephrine, histamine, and 5-hydroxytryptamine (serotonin)
_________ is accomplished by a brainstem neuronal pathway known as the ascending reticular activating system (ARAS)
Wakefulness
Sleep is maintained by inhibition of the ARAS via a hypothalamic nucleus known as the ventrolateral preoptic (VLPO) nucleus which involves which neurotransmiters
γ-aminobutyric acid (GABA) and galanin
_____ promotes sleep by inhibiting cholinergic ARAS neurons and activating VLPO neurons
Adenosine
The hallark of OSA is?
sleep-induced hypoxia and arousal-relieved upper airway obstruction
Predisposing factors to OSA include
o genetic inheritance o non-Caucasian race o upper airway narrowing o obesity o male gender o menopause o use of sedative drugs and alcohol o cigarette smoking
Direct physiologic mechanisms involved in the pathogenesis of OSA include?
1) anatomic and functional upper airway obstruction
2) a decreased respiratory-related arousal response
3) instability of the ventilatory response to chemical stimuli
In OSA obstruction can be due to
bony craniofacial abnormalities, or excess soft tissue, such as thick parapharyngeal fat pads, or enlarged tonsils
Children have many reasons for anatomic upper airway narrowing, including
the very common enlargement of tonsils and adenoids, as well as the much less common congenital airway anomalies
For every 1-point increase in the Mallampati score, the odds ratio for OSA is increased by?
2.5 times
The respiratory-related arousal response is stimulated by:
1) Hypercapnia
2) Hypoxia
3) Upper airway obstruction
4) The work of breathing, which is the most reliable stimulator of arousal
Obesity is a risk factor for OSA in all age groups. __________ increase in body weight is associated with a ______ increase in the odds of having OSA and a ______increase in the apnea-hypopnea index
10%
6-fold
32%
A _____ weight loss is associated with a _______ decrease in the apnea-hypopnea index
10%
26%
Diagnosis criteria for OSA
- S/S: daytime sleepiness, fatigue, insomnia, snoring, subjective nocturnal respiratory disturbance, observed apnea
- Associated medical or psychiatric disorders such as HTN, CAD, afib, CHF stroke, DM, cognitive dysfunction, and mood disorders
- Predominantly obstructive respiratory events recorded during sleep center nocturnal PSG or during out-of-center sleep testing
What factors put children at an increased risk for respiratory complications?
o History of copious secretions o Prematurity o Parental smoking o Nasal congestion o Reactive airway disease o Endotracheal intubation o Airway surgery o Clear systemic signs of infection (fever, purulent drainage, productive cough, and rhonchi)
Identify adverse events in pts with URIs:
o Bronchospasm o Laryngospasm o airway obstruction o postintubation croup o desaturation o atelectasis o hypoxemia
Asthma is REVERSIBLE airflow obstruction characterized by?
o Bronchial hyperreactivity
o Bronchoconstriction
o Chronic airway inflammation
Genetic and environmental causes of asthma include?
o Family Hx
o Maternal smoking during pregnancy
o Viral infections (esp rhinovirus and infantile RSV)
o Exposure to highly infectious environments (farms, daycares, pets)
What is the pathophysiology of asthma?
o Chronic inflammation of lower airways
o Activation of inflammatory cascade → infiltration of airway with eosinophils, neutrophils, mast cells, T & B cells, and leukotrienes
o End result = airway edema (especially in the bronchi)
What are the signs and symptoms of asthma
o Characterized by acute exacerbations mixed with periods of no symptoms
o Wheezing, productive or nonproductive cough, dyspnea, chest tightness that may lead to air hunger, and eosinophilia
What are PFT findings in asthma
o FEV1, FEV1/FVC ratio, and FEF25-75% all reduced but improve with bronchodilators.
o Downward scooping of the expiratory limb of the flow-volume loop.
o Bronchodilator responsiveness provides supporting evidence if asthma is suspected based on S/S
Identify short acting bronchodilators used for immediate relief of asthma
Albuterol
Lavalbuterol
Metaproterenol
Pirbuterol
Side effects of beta 2 agonists include?
Tachycardia
Tremors
Dysrhythmias
Hypokalemia
Identify the factors that could cause increased airway resistance during general anesthesia
Depression of the cough reflex
Impairment of mucociliary function
Reduction of the palatopharyngeal muscle tone
Depression of diaphragmatic function
Increased fluid in the airway wall
Airway stimulation by endotracheal intubation
Parasympathetic nervous system activation
Release of neurotransmitters of pain (sub p & neurokinin) may play a role
Identify preop risk factors for periop respiratory complications during general anesthesia for a patient with asthma
Eosinophilia parallel the degree of airway inflammation
Reduction in FEV1 or forced vital capacity (FVC) to <70% of predicted
FEV1:FVC ratio < 65% of predicted
life threatening bronchospasm that persists despite treatment
Status asthmaticus
Describe the treatment of status asthmaticus
o Emergency tx = B2 agonists
o Early tx: IV corticosteroids (Hydrocortisone & Methylprednisone)
o Supplemental O2 to maintain sats >90%
o Magnesium and oral leukotriene inhibitors may be used for refractory cases
o Presence of hypercarbia requires tracheal intubation and mechanical ventilation
o Ventilator settings should be adjusted to prolong the expiratory phase to allow for complete exhalation and to prevent auto-PEEP
o In rare, life-threatening circumstances where status asthmaticus is resistant to pharmacologic therapies, GA (Sevo or Iso) may be initiated to produce bronchodilation
What is the normal FVC
Male 4.8 L
Female 3.7 L
What is the maximum minute ventilation
Males = 140- 180 Female= 80- 120
What are the S/S of bronchospasm intra-op?
- High peak airway pressure
- Upsloping of ETCO2 waveform
- Wheezing
- Desaturation
Other differential diagnosis of intra-op bronchospasm and wheezing include ?
o Kinking o Secretions o overinflation of ETT cuff o light anesthesia o endobronchial intubation o aspiration o pulmonary edema o PE o Pneumo o acute asthma attack
Progressive loss of alveolar tissue and progressive airflow obstruction that is NOT reversible
COPD
___________ and ___________ develop as progressive pulmonary fibrosis results in the loss of pulmonary vasculature.
Pulmonary hypertension and cor pulmonale
In a patient with pulmonary fibrosis, dyspnea is prominent and breathing is?
rapid and shallow
Inflammatory disease characterized by growth of benign inflammatory masses
Sarcoidosis
___________ are administered to suppress the manifestations of sarcoidosis and to treat hypercalcemia
Corticosteroids
___________ may be necessary to provide lymph node tissue for the diagnosis of sarcoidosis
Mediastinoscopy
____________ leads to pulmonary fibrosis and no treatment has been shown to be beneficial for this disease.
Eosinophilic Granuloma
Condition of unknown etiology that results in deposition of lipid-rich proteinaceous material in the alveoli. Present with dyspnea and arterial hypoxemia. May occur independently or in association with chemotherapy, AIDS, or inhalation of mineral dusts.
Alveolar Proteinosis
________may be needed to remove the alveolar material and improve macrophage function in a patient with alveolar proteinosis.
Whole-lung lavage
Double lumen tube is needed for lung lavage to separate lungs during lavage of a patient with alveolar Proteinosis to
optimize oxygenation during the procedure
Hypodynamic shock
o Decreased CI and vasoconstriction
o Decreased CO results in increased oxygen extraction and lactic acidosis
o Organ dysfunction from inadequate blood flow
o Includes hypovolemic shock, cardiogenic shock, and obstructive shock
Causes of hypodynamic shock includes?
Hypovolemic shock
Cardiogenic shock
Obstructive shock
Hyperdynamic shock
o High CI and vasodilation
o Normal or decreased oxygen extraction
o Increased or normal filling pressures depending on volume status and myocardial performance
o Organ dysfunction from maldistribution of blood flow, rather than inadequate blood flow
o Causes: sepsis, severe trauma, anaphylaxis, specific drug intoxications, neurogenic shock, adrenal insufficiency, and severe pancreatitis
Causes of hyperdynamic shock include?
- Sepsis
- severe trauma
- anaphylaxis
- specific drug intoxications
- neurogenic shock
- adrenal insufficiency
- severe pancreatitis
The hallmark sign of hypovolemic shock is?
Decreased filling pressures
Causes of hypovolemic shock include?
Hemorrhage, dehydration, and massive capillary leak
The most common cause of cardiogenic shock is?
MI involving 40% or more of the left ventricle
causes of cardiogenic shock are?
o Acute MI involving 40% or more of left ventricle
o Cardiomyopathies
o Valvular lesion
o Increased cardiac filling pressures
o Due to LV failure or mechanical complications
Systolic dysfunction in cardiogenic shock results in?
Decreased CO and SV
Systemic perfusion is decreased, which results in compensatory vasoconstriction and fluid retention…further leading to myocardial dysfunction
Hypotension decreases coronary perfusion pressure and worsens MI
Diastolic dysfunction in cardiogenic shock results in?
Increase LVEDP, pulmonary congestion, and hypoxemia
The most common cause of obstructive shock is ?
Pericardial tamponade
Acute PE
Tension pneumothorax
_______ may have similar clinical manifestations to obstructive shock?
Cardiogenic shock
In obstructive shock, cardiac filling pressures usually increased from?
Outflow obstruction
Impaired ventricular filling
Decreased ventricular compliance
Initial fluid challenge for sepsis is?
30 mL/kg
Vasopressors for treatment of sepsis
Norepinephrine the first line vasopressor for septic shock (and cardiogenic)
If MAP < 65 mm Hg, add epinephine
If MAP still < 65 mmHg, add vasopressin 0.03-0.04 U/min
Dobutamine can be added in the presence of myocardial dysfunction or when hypoperfusion persists
Target Hgb in septic shock is?
7-9 g/dL
______ shock is similar to septic shock
Traumatic shock
Multifactorial, including a distributive immunologically mediated response to injury as well as shock from hemorrhage
Traumatic shock
The most common cause of preventable hospital death is?
PE
Features of PE
(1) transient dyspnea and tachypnea
(2) pulmonary infarction or congestive atelectasis manifested by pleuritic chest pain, cough, hemoptysis, pleural effusion, or pulmonary infiltrates
(3) right ventricular failure associated with severe dyspnea and tachypnea
(4) cardiovascular collapse with hypotension, syncope, and coma (massive PE)
(5) nonspecific symptoms including: confusion, coma, pyrexia, wheezing, recalcitrant HF, and dysrhythmias
Cardiac reflexes of the heart
Brainbridge reflex
Oculocardiac reflex
Celiac plexus stimulation
Brainbridge reflex
Variation in the R-R this reflex which accelerates the HR when intrathoracic pressure is increased during inspiration and slows the HR when the intrathoracic pressure decreases during expiration
Occulocardiac reflex:
bradycardia due to traction on eye muscles
Celiac plexus stimulation
bradycardia due to traction on the mesentery
In antidromic form of AVNRT (wide QRS tachycardia) what drugs should be avoided and which should be given
DO NOT GIVE adenosine, CCB, β-blockers, or amiodarone
DO GIVE procainamide 10 mg/kg then cardiovert if drug therapy unsuccessful
In orthodromic AVNRT (narrow QRS tachycardia) what drugs should be avoided and which should be given
Perform vagal maneuver, then give adenosine, verapamil, β-blockers, or amiodarone
Treatment for mobitz II
Transcutaneous/ transvenous cardiac pacing
Permanent pacemaker
Isoproterenol > Atropine
Treatment for Mobitz I (wenckebach)
Atropine if the patient is symptomatic
If atropine is ineffective, pacing is indicated
Anesthetic management for a patient with 3rd degree block
o Transcutaneous or tranvenous cardiac pacing
o Isoproterenol may be helpful in maintaining an acceptable HR
o Caution with administering antidysrhythmic drugs!
o Preop placement of a transvenous pacemaker or the availability of transcutaneous cardiac pacing is necessary before an anesthetic is administered for insertion of a permanent cardiac pacemaker
The most common cause of 3rd degree AV block in adults is?
Lenègre disease: fibrotic degeneration of the distal conduction system associated with aging
Causes of 3rd degree block
Lenègre disease: fibrotic degeneration of the distal conduction system associated with aging
Lev disease: Degenerative and calcific changes in more proximal conduction tissue adjacent to the mitral valve annulus can also interrupt cardiac conduction
Onset of 3rd degree block may be signaled by
Syncope/vertigo aka “Stokes-Adams attack”
Treatment for torsades
magnesium 1-2 g over 5 min
Features of Tosades
- ‘Delta wave’ - ventricular preexcitation causing a slurred upstroke to the QRS complex
- PRI < 120ms
- QRS > 120ms
- Inherited disorder
- AVNRT is the most common tachydysrhythmia seen in patients with WPW syndrome
- Orthodromic AVNRT
- Antidromic AVNRT
Normal mitral valve orifice area is?
4-6 cm2
Symptoms usually develop with mitral valve area is?
less than 1.5 cm2
broad notched P waves suggest?
atrial enlargement
Diagnostic findings of CXR in mitral stenosis
left atrial enlargement resembles straightening of the left heart border and elevation of the left mainstem bronchus
opening snap that occurs early in diastole and a rumbling diastolic heart murmur
Mitral Stenosis
Best heard at the apex or left axilla
Intraoperative events that have a significant impact on mitral stenosis
- Sinus tachycardia
- Afib with RVR
- Marked increase in blood volume i.e transfusion/trendelenburg
- Drug induced decrease in SVR
- Hypoxemia and hypercarbia that may exacerbate pulmonary hypertension and evoke right ventricular failure.
In MR pt Neuraxial anesthesia is acceptable in the absence of anticoagulation
True
what are the 2 factors associated with the development of aortic stenosis
Age related degeneration and calcification
Presence of a bicuspid aortic valve
Most common congenital valvular abnormality that causes aortic stenosis earlier in life
Bicuspid aortic valve
Aortic aneurysms grow faster in patients with _______________, and there is a higher risk of aortic dissection and rupture..
Bicuspid aortic valve
Normal aortic valve area is?
2.5-3.5 cm2
Transvalvular pressure gradients higher than ________ and an aortic valve area of less than_________are characteristic of severe aortic stenosis
50 mmHg
0.8 cm2
Management of anesthesia in aortic stenosis
o Maintain NSR
o Avoid bradycardia or tachycardia
o Avoid hypotension
o Optimize intravascular fluid volume to maintain venous return and left ventricular filling
induction in a patient with aortic stenosis
General anesthesia in preference to epidural or spinals because risk of hypotension
Use IV induction drug that does not decrease SVR
Etomidate and benzodiazepines
An opioid induction agent may be useful if left ventricular function is compromised
Ketamine may induce tachycardia and should be avoided
Diagnosis of a STEMI is made by:
o Ischemic symptoms
o Pathological Q waves noted on EKG
o EKG changes indicative of new ischemia such as LBBB or ST changes
o New onset of myocardium or regional wall abnormality evidenced by imaging
Sign and symptoms of a STEMI include?
Diaphoresis, anxiety, sinus tachycardia, hypotension, notable dysrhythmias, and rales
Clinical management of STEMI includes?
o Initiation of oxygen therapy
o IV Morphine
o SL Nitroglycerine (decreases catecholamine release and O2 requirements)
o Asprin or P2Y12 inhibitors
o β-blockers when appropriate
Be cautious in heart block or in low CO
o Thrombolytic therapy, coronary angioplasty, CABG if failed PCI, and adjunct medical therapy
Diagnosis of UA/NSTEMI is made by pt exhibiting these 3 principle presentations:
- Angina at rest longer than 20 mins
- Chronic angina that is more frequent and easily provoked
- New onset of angina that is prolonged, disabling, and very severe
• Unstable angina/Non-ST segment elevation result from a reduction in myocardial oxygen supply. Five pathophysiological process contribute cause which are:
o Nonocclusive thrombosis (from coronary plaque)
o Vasoconstriction (from cocaine use, cold, variant angina)
o Atherosclerosis
o Inflammation (ex. vasculitis)
o Increased oxygen demand due to myocardial ischemia
Signs and Symptoms of Unstable Angina/NSTEMI include:
o Hemodynamic instability
o Symptoms of CHF
o EKG abnormalities (ex. ST segment elevation, ST depression, T wave inversion
o New regional wall motion abnormality on ECHO and elevated cardio biomarkers levels establish the diagnosis of an ACUTE MI
