OB Final Comprehensive Flashcards
EKG changes associated with aging
Left Ventricular Hypertrophy - Left axis deviation
Aging and Diastolic dysfunction: LV
LV is thicker and less compliant
Complete relaxation later in diastole
Aging and Diastolic dysfunction: Passive ventricular filling
Passive ventricular filling compromised
Aging and Diastolic dysfunction:atrial kick
Atrial kick becomes very important
Aging and PPVs
Greater sensitivity to PPV, hemorrhage, venodilators
Aging and perioperative pressure
Perioperative hypotension common
Changes with Aging Systolic
There is systolic hypertension
Progressive, gender independent
Systolic HTN due to
Due to fibrosis of elastic tissues
Ventricular wall tension
Raises ventricular wall tensions, workload
Causes hypertrophy of ventricle
It takes pts c/obstructive dz
twice as long to exhale: I:E is 1:2
ETCO2 look like
Shark fin
Obstructive airway shark pattern
Can be seen before actual attack
Shark fin CO2 waveform indicative of
Asthma, COPD, allergic reaction
MAC changes with aging
↓ 6% per decade of age over 40 yrs.
Calculating MAC reduction
Relative MAC or ED50 = 114% - 0.5* (age)
Treating Hypotension
Use direct acting vasopressors
For older adults, Therefore volume of distribution
for lipid soluble is _____
Greater for lipid soluble agents
For older adults, Therefore volume of distribution
for WATER soluble is _____
Decreased
For Older adults, Lipid soluble drugs take
longer to clear because of the larger volume of distribution
MAC of anesthetics is____in the elderly
↓
Most prominent pharmacokinetic effect of aging:
decrease in drug metabolism
Pharmacokinetics: Clearance and Vd
Metabolism
Decrease in clearance and increased volume of distribution at steady state
↓ intravascular volume leads to _____Vd of water soluble drugs = __________ = ___action = _____Dosage
↓ Vd for water soluble drugs = more drug remains available = ↑ action = need to ↓ dosage (i.e. Neuromuscular blockers)
Drug metabolism , there is
Modest reduction in phase I drug metabolism
Decreased liver mass
20-40% decrease in blood flow
Water soluble drugs
Decrease the dose
Lipid soluble drugs
Decrease the dose
Greater effects are seen when drugs encounter a
lower volume of distribution
Lipid soluble drugs take
longer to clear because of the larger volume of distribution
When choosing an anesthetic technique
Pay attention to doses (less is more = A minimal approach is more effective)
Need to ↓ dosage
(i.e. Neuromuscular blockers)
↑ sensitivity to
respiratory depression with non-narcotics
like benzodiazepines.
β adrenergic response in elderly
Marked ↓ in β adrenergic response in elderly
Activity of MAO and COMT
Increase
CBF in elder is
Decrease
Up regulation mechanisms
Depressed in elderly patients
Usually respond to ↓ in neurotransmitters
CSF volume is
Decreased in elderly, greater LA spread (reduce dose)
Epidural space volume is
Decrease
Law of laplace –> Cylinders Applies to ______, formula is
Applies to two situations Laplace
• Cyliners (veins/arteries)
• T = P X R
Law of laplace –> Spheres Applies to ______, formula is
- Spheres (heart)
* T = (P X R)/2
Laplace, What does this mean?
At the same radius and internal pressure, a sphere has half the wall tension as a cylinder
La place, variable
- T = tension in newtons per meter
- P = pressure
- R = radius of cylinder or sphere in meters
Elderly patients
Cannot compensate by increasing CO and HR. They
compensate by vasoconstriction
Elderly patients cannot? how do they compensate?
Cannot compensate by increasing CO and HR. They
compensate by vasoconstriction
Elderly and RV
↑ RV,
Elderly and TLC
stays the same TLC,
Elderly and RR
↑ respiratory rate
Elderly VC and FEV1
↓ VC and FEV1
•Heart rate changes are
usually blunted in elderly
HR changes Affects ability to
compensate for volatiles causing vasodilation
HTN and elderly
Aorta to arterioles stiffen = HTN
• Pressure must ↑ to stretch stiffer vessel
Vital signs changes
RR increase
BP increase
Max HR should =
220 – age
Max HR normally
↓ approximately 1 beat/min/year after 50 yo
Men and women both gain adipose tissue
Men gain 12kg of fat
• Men lose 8kg of muscle
Muscle and elderly
Reduction in muscle mass limits drug removal by muscle
Skeletal muscle mass
Progressive, generalized ↓ of skeletal muscle mass
Total body water and elderly
Total body water is ↓
ALbumin and elderly
↓ Albumin Production
Elderly and bony thorax
↓ of elasticity of bony thorax
ELderly and lung compliance
While lung compliance ↑ → air trapping
Elderly and alveolar gas surgace
↓ alveolar gas surface area
Elderly and nervous system response
• ↓ in nervous system response to hypoxemia and hypercarbia
Elderly and parenchymal compliance
↑ parenchymal compliance
• Takes longer to passively exhale
Vital capacity (VC) and elderly
↓ because of the ↓ in IC and the ↑ in residual
volume.
Elderly and dead space
Increase
Most dramatic change with aging is the
↑ in closing volume (CV) and closing capacity (CC) such
that in very old pts, closing capacity exceeds functional
residual capacity
• Responses to hypoxemia
Decrease
GFR and Cr clearance are
↓
• Renal mass is
↓
Renal blood flow
↓
Serum Cr
remains the same
Creatinine production is
↓
Explain GFR and muscle mass
GFR decreases (should really increase Cr but because there is decrease in muscle mass so less cr)
Parkinson Pathophysiology•
Adult onset degenerative disease of the CNS (extra pyramidal system), characterized by the loss of dopaminergic fibers normally present in the substantia nigra of the brain
The cause is unknown, and males between
The ages of 40 –70 are most typically afflicted.
Parkinson’s and autonomic dysfunction
Autonomic dysfunction (risk for aspiration)
Parkinson short
Decrease Dopamine in the basal ganglia
Parkinson’s and BP
• Labile blood pressure and cardiac dysrhythmias from the
disease and the treatment (levodopa, MAO inhibitors)
Medication exacerbations with levodopa
Be aware of possible orthostatic hypotension,
cardiac dysrhythmias associated with levodopa
Hemodynamics monitoring for Parkinsons : anesthetic management may need
Arterial line
Medication exacerbations with levodopa : Avoid those 2 meds
Avoid droperidol and metoclopramide
Phenothiazines, butyrophenones, and metoclopramide
exacerbate symptoms because antagonism of dopamine in the basal ganglia
Antagonism of dopamine in the basal ganglia 3 meds
Phenothiazines, butyrophenones, and metoclopramide
Ketamine and Parkinson effect:
Exaggerated sympathetic response
Anticholinergics and Parkinson
control the tremors
Post Operative Cogniitive dysfunction
Increased risk from Bypass and Cataract Surgeries
10-60% Hip fractures
Post op delirium Causes
***Advanced Age a strong predictor*** • Polypharmacy • Anticholinergics • Intra op hypotension • Perioperative Arterial Hypoxemia • Opioids or benzodiazepines • Central Cholinergic System always
What is the most important risk factor for delirium?
Co existing dementia most important risk factor
Causes of Delirium (PIA HAH)
• Psycho active drugs • Infections • Alcohol withdrawal • Hypoxemia Acute physical stress • Hypotension
Cortical Dementias
Alzheimer’s, Pick’s, Frontal Lobar degeneration
Sub cortical Dementia
Parkinson’s, Huntington’s, Creutzfeldt Jacob
Progeria also known as
Hutchinson-Gilford Syndrome
Progeria is associated with
Premature Aging
Genetic with Progeria
Autosomal Recessive Disorder
Mean Survival for Progeria
13 years
Progeria Death by
25 common
Progeria difficult airway due to
- Micrognathia
* Mandibular Hypoplasia
Fetal shunt in the liver blood flow through the
Ductus venosus
When Ductus Venosus closes remnant is
LIGAMENTUM VENOSUS
When Ductus Arteriosus closes it becomes
LIGAMENTUM ARTERIOSUM
DUCTUS venosus shunt is
Liver
What are the 4 shunts
Ductus Venosus : Joins IVC blood, blood bypasses liver
Foramen Ovale : right atrium to Left atrium
Ductus Arteriosus: pulmonary artery to Aorta
Placenta
What is the ratio of R to left contribution in fetal circulation
2:1 Right to left ration
Right is 2x LV output because of R to L shunt
Functional closure of shunt happens
Immediately after birth
Order of shunt
Ductus venosus IVC Foramen Ovale Ductus Arteriosus Umbilical arteries (return to placenta)
1st stage pain comes from
T10-L1(L2) DERMATOMES
2nd second stage pain is mediated by
THE SACRAL PLEXUS
T12-L1, S2-S4
This nerve block provides sensory to perineum
The Pudental Block
Not always completely anesthetized with epidural
The Pudental NERVE
Dull, diffuse midline define
Visceral
Sharp, pricking, throbbing,and/or burning sensation
Somatic
1st stage of labor
onset of true labor until cervix is completely dilated (10 cm)
2nd stage of labor
period after cervix dilated to 10cm until the baby is delivered.
1st stage subdivisions
Early labor phase: time of onset until cervix dilated
3cm
Active labor phase: cervix dilates from 3cm to 7cm
Transition phase: cervix dilates from 7cm to 10 cm
1st stage Dull pain transmitters are the
Cervical dilation mediated by
unmyelinated C fibers
Onset perineal pain is associated with
2nd stage.
4 types of Placenta Previa
TPML
Total
Partial
Marginal
Low-lying placenta
What is a TOTAL placenta previa?
Internal cervical OS covered completed by placenta
What is a PARTIAL placenta previa>?
Internal cervical OS partially covered by placenta
What is a MARGINAL placenta previa?
Edge of placenta at margin of internal os
What is a low lying placenta?
Placenta is implanted in lower uterine segment –> Placental edge does not actually reach internal os but in close proximity to it
VASA Previa is
rare condition where fetal vessels from placenta cross entrance of birth canal
3 typical causes of Vasa previa
Bi-lobed placenta
Velamentous insertion of umbilicord
Succenturiate (accessory lobe)
Placenta Accreta vera is
Adherence of basal plate of placenta directly to uterine myometrium without penetrating the decidua layer
Placenta Accreta increta is
Chorionic villi invade myometrium
Placenta accreta percreta is
Invasion through MYOMETRIUM into SEROSA and even adjacent ORGANS (bladder)
Weight estimation (less than 8 )
Wg (kg) = 2 x age (years) + 9 if less than 8
Weight estimation (more than 8 )
age (year) x 3
Weight double by
6 months
Pediatric tongue
larger in proportion to mouth
Pediatric Epiglottis
Floppier more U shaped
Vocal cord pediatric
Upward slant
Larynx of pediatric
Anterior, superior and located between C2-C4
Pediatric
Obligate Nose breathers
Premie EBV
100
Newborn EBV
90
3 months to 1 year
80
3 months to 1 year EBV
80
1 year + EBV
75
Adult EBV
65-75
ABL
EBV (starting - final / starting)
Distance for ETT
age (years) /2 +12
weight (kg)/5 + 12
ETT ID x 3
Succinylcholine dose is
1-2mg/kg IV
4mg/kg IM
Methohexital dose is
1-2mg/kg IV
Propofol dose is
3mg /kg IV
Ketamine IV
1mg/kg IV
Etomidate
0.2-0.3 mkg/kg
Ketamine IM
3-4 mg/kg
Midazolam dose IV/IM
0.1mg/kg
MAX MIDAZOLAM
12 MG
Ketamine PO and rectal dose
6-10mg/kg
Ketamine IM dose for GENERAL INDUCTION
6-10MG/KG
Fentanyl dose is
1MCG/KG
Morphine
0.1mg/kg
Midazolam dose intranasal
0.2mg/kg
Versed+ ketamine
0.4 and 4 mg for successful separation
Airway position and levels
Airway cartilages
Airway Anterior , C2-C3
Afferent signaling provided by
- Peripheral arterial
- Upper airway
- Chest wall
+ central brainstem chemoreceptors
+intrapulmonary receptors
+ muscle mechanoreceptors
Nose, pharynx, larynx contain what?
what can they cause?
pressure, chemical, temperature, and flow receptors
Can cause apnea, coughing, changes in ventilation
Pulmonary receptors in lung parenchyma
What kind of receptors are they ? aka_______
Where are they located?
What do they balance?
These receptors may be involved and Cause what reflex?
That reflex Prevents what?
Slowly adaption receptors (stretch receptors)
In airway smooth muscle
Balance of inspiration/expiration
Might cause Hering-Breuer reflex
Prevents overdistention of lungs via vagal stimulation/ and prevents COLLAPSE OF THE LUNGS
Rapidly adapting receptors located where ?
Triggered by ___________
such as _____________
Between airway epithelial
Triggered by noxious stimuli
Dust, smoke, histamine
Parenchymal receptors located __________
next _________
Juxtacapillary receptors
• Next to alveolar blood vessels
Parenchymal receptors respond to what? (3)
• Respond to hyperinflation, chemical stimuli in pulmn.
circ., interstitial congestion
Chest wall Receptors are
Located in?
Sense changes in
Also have
- Mechanoreceptors
- In muscle spindle endings and tendons of resp. muscles
- Sense change in length, tension, and movement
- Joint properioreceptors
Aryepiglottic fold (paired)
❑Epiglottis to arytenoids
❑False cords
Vestibular folds (Thyroid cartilage to arytenoids)
❑Interarytenoid fold (single)
Bridge
❑True vocal cords
Thyroid cartilage to arytenoids
Larynx position in kids
❑Higher @ C3-4
❑Higher in premature infants
❑Adult @ C4-5
The Larynx of Peds One bone = How many cartilages? What are the single cartilages? Single: Paired:
Hyoid
11
thyroid, cricoid, epiglottic
arytenoid, corniculate, cuneiform, triticeal
- Arytenoid rest on ______
* Suspended by
rest on top, connects with superoposterior part of cricoid cartilage
To access high epidural assess
C6 , around thumb
1st stage of labor mediated by what fibers
Unmyelinated C fibers
Fetal blood flow
Umbilical veins Ductus venosus Foramen Ovale Ductus Arteriosus Umbilical Artery.
Majority of blood flow to uterine
intervillous space
Low fetal O2
Placental HIGH O2 consumption
Admixture of Oxygenated and Unoxygenated blood.
3 parameters increased in the elderly (RESP)
Residual volume
FRC
Closing Capacity
Elastic recoil of lung in the elderly
Loss of elastic recoil
In the elderly , loss of elastic recoil leads to
Air trapping
Why is there no change in TLC
Decreased VC
Increase RV
No net change
Venous capacitance is______Which leads to
decreased (greater lability with BP in OR,
Hypertrophy of LV is
Eccentric
BP and aging
Increase BP
Pulse pressure and aging
Increase
Baroreceptor sensitivity is
DECREASE
Parasympathetic Tone is _______therefore response to anticholinergic is ______
Decreased (decrease response to anticholinergic such as atropine)
Onset of postop Cognitive dysfunction
Weeks to month after surgery
Ease of identificiation delirium vs post op cog
Delirium easy
Post op Cog dys subtle and difficult to pinpoint
Most significant risk factor for post op cog
Advanced age
Neuraxial change in the elderly EPIDURAL why?
Greater spread of LA; reduction of epidural space
Neuraxial change in the elderly SPINAL why?
Greater spread of LA; reduction of in CSF VOLUME
Higher rate of false negative test dose with EPInephrine why?
Decrease beta receptor sensitivity
Aldosterone sensitivity
decreased.
Pseudocholinesterase and aging
decreased
Larger VD for
Lipophillic drugs (may prolong their elimination)
Smaller Vd for
Hydrophillic drugs
Decrease CO prolongs circulation time which leads to
Faster Inhalation inductions
SLOWER IV INDUCTION
Lung compliance and aging
Increase
Chest wall compliance
Decrease
Local anesthetics dose should be
Decreased
Spinal anesthesia duration is
longer
Airway protective reflexes in elderly are
Decreased
Residual volume to lung capacity ration
Increased.
No significant change in PharmoK. Profile of
NMB such as atracurium
Uncuff formula
Age/ 4 + 4
Cuff formul
Age/4 + 3
Insertion distance
Age/2 + 12
Weight/5 + 12
ID x 3
