Maintenance of the Anesthetized Patient Flashcards
Goals of maintenance (7)
maintenance of:
- ) anesthesia
- ) amnesia
- ) analgesia
- ) paralysis
- ) minimize negative effects of anesthetic
- ) fluid maintenance/ balance/ fluid resuscitation
- ) cardiac output and end organ perfusion
Why do anesthetists use monitors?
- ) detect deficit or overdose of anesthetic agents
- ) early detection of adverse events
- ) prevention of perioperative critical events
Respiratory parameters assessed continuously (4)
- ) airway
- ) respiratory rate, depth and quality
- ) oxygen saturation (SPO2)
- ) Capnography
Cardiovascular parameters assessed continuously (4)
- ) heart rate and rhythm
- ) pulse rate and strength
- ) mucous membrane color and capillary refill time
- ) arterial blood pressure
Other parameters assessed continuously
- ) body temperature
- ) anesthetic depth/pt status
- ) Equipment function
Manual monitoring techniques provide valuable information about ___ and ___.
depth of anesthesia; diagnosis of intraoperative complications
Manual monitoring techniques (3)
- ) visual inspection
- ) palpation
- ) auscultation
What do you watch out for during visual inspection? (6)
- ) Diaphoresis
- ) spontaneous movement
- ) respiratory rate and pattern changes esp when spontaneous
- ) abnormal retractions or inspiration
- ) cyanosis
- ) skin color and/or rash
What do you palpate for? (4)
- ) tracheal position
- ) subcutaneous emphysema
- ) pulsus paradoxus
- ) heart rate, rhythm
What do you auscultate for in respiratory system? (3)
- ) endotracheal tube placement/malposition
- ) wheezes/crackles
- ) stridor/decreased air entry
what do you auscultate for in cardiovascular system? (2)
- ) murmurs/bruits
2. ) changes in quality of heart sounds
2 ways to monitor rate and depth of respirations
- ) movement of chest
2. ) reservoir bag
Difficult or labored breathing may indicate the presence of what?
airway obstruction
Normal RR
8-12 breaths/min
abnormally low RR
<6
normal inspiration and expiration lasts how long?
1-1.5 seconds; 2-3 seconds expiration
How do you evaluate respiratory rate and quality of breath sounds?
esophageal stethoscope
What should you do if you see an increased ETCO2 on capnography?
- ) increase minute ventilation (RR or Vt)
2. ) check CO2 absorber
What should you do if you see decreased ETCO2 on capnography?
- ) sudden vs. slowly
- ) decrease ventilation
- ) verify other signs of hypoperfusion
measure how much carbon dioxide is present in the patients breath
capnography
respiratory alkalosis
<35
respiratory acidosis
> 45
Normal capnography
35-45 mmHg
Which gas absorbs infrared waves with wavelengths of 4.5 micrometers?
nitrous oxide
Direct reflection of capnography
elimination of CO2 by the lungs to the anesthesia circuit
Indirect reflection of capnography
production of CO2 by tissues and the circulatory transport of CO2 to the lungs
ETCO2 for a spontaneously ventilated pt
ETCO2 over 45 at incision
Respiratory function of a light patient (3)
- hyperventilation- increased RR/Vt and hypocapnia
- breath holding
- bronchospasm/laryngospasm
Respiratory function of a deep patient (1)
hypoventilation, decreased RR, Vt, and hypercapnia
Examples of non-invasive monitors
- ) expired agents/gases
2. ) end tidal agents/gases
What can you do to the end tidal agent/gases if low and a patient appear light? (2)
- ) increase flow rate
2. ) increase percent of volatile agent delivered from vaporizer
Factors that affect MAC (5)
- ) IV meds
- ) pre-op medications
- ) age
- ) medical conditions/patient health
- ) hypo/hyperthermia
Hypoventilation
decrease in both rate and tidal volume, alveoli can’t inflate and atelectasis
How should you handle an apneic pt?
manually ventilate throughout procedure for 8-12 bpm
increased CO2 in the blood and metabolic acidosis causes what?
tachypnea and hyperventilation
what might happen as a response to surgical stimulus? (2)
hyperventilation, high blood pressure
High ventilatory pressures is an early indication of ____
light anesthetic
Problems associated with high ventilatory pressure (4)
- ) ventilator
- ) breathing circuit
- ) ETT
- ) pulmonary, chestwall compliance
Treatment for high ventilatory pressure (3)
- deepen anesthetic
- paralysis
- reposition/suction/change ETT
percentage of oxygen saturated Hgb and indicates how well the lungs are delivering oxygen to the blood
pulse oximeter (pulseOX) SPO2
pulse ox measures ___ and ___ continuously.
SPO2 and heart rate
pulse ox of 90-95% indicates what?
hemoglobin is not fully saturated and a respiratory or cardio problem may be present
when does a pt become hypoxic
<90%
cyanosis may occur at what SPO2 value?
<85%
How do you asses for heart rate and rhythm?
auscultation
bradycardia may indicate what? (2)
- ) excessive anesthetic depth
2. ) response to vagal stimulation or other causes
Inadequate anesthetic levels might cause?
tachycardia
How should heart beat be assessed?
pulse rate strength and quality
result of respiratory failure or upper airway obstruction
cyanosis
time for color return to a mucous membrane after the application of gentle pressure
capillary refill time
a prolonged capillary refill time >2 seconds may indicate ____ resulting from excessive anesthetic depth or circulatory shock
hypotension
Factors that prolong CRT (4)
- in pts with systolic blood pressure <80 mm Hg
- hypothermia
- vasodilation
- cardiac failure
Ways to monitor arterial blood pressure
- ) automated oscillometric device
- doppler ultrasound probe coupled with a pressure cuff
- ) sphygmomanometer
When a bp cuff is too small what happens?
reading that’s too high and error can be as much as 50 mm hg
minimum acceptable BP
80/40
Causes of hypotension
- excessive anesthetic depth
- hypovolemia (due to intraoperative bleeding or pre-op dehydration)
- hypothermia
- hypoxia
How does general anesthesia affect core body temperature?
Initially, rapid decrease within first 1/2 hour up to slow linear reduction in core temperature up to 2 hours after induction then usually stabilizes after 3-4 hours
basic rule of anesthetic depth of pt
decrease vaporizer setting
eyelash reflex disappear during what stage of anesthesia
stage 2
eyelid reflex is lost during which plane of stage 3 anesthesia
plane I
Types of reflexes (6)
- palpebral
- swallowing
- laryngeal
- jaw tone
- eye position, pupil size, pupillary light response
- heart and respiratory rates
how much MAC do you give for the first several minutes after induction?
1.5-2 MAC
What flow rate should you use for oxygen?
0.5-2 L/min
variable derived from EKG, measures the hypnotic effect of anesthetic
bispectral index
which analgesic is slower onset and longer acting and must be titrated to respiratory rate at end of case?
morphine/hydromorphone
what should you do to the volatile agent if patient is too light?
- ) increase flow rates of O2/air/ N2O
2. ) increase concentration from vaporizer
What should you do to the volatile agent if a patient is too deep?
1.) increase flow rates AND DECREASE vaporizer concentration
The MAC necessary to prevent response to verbal/tactile stimulation
Volatile: 0.3
N20: 0.6
The MAC necessary to blunt the autonomic response to a noxious stimulus
1.6 MAC
the MAC necessary to prevent laryngeal response to endotracheal intubation
1.3 MAC
what should you give if patient has decreased BP, increased HR, decreased urine output ?
fluids
what iv agent is used for awake patients?
midazolam
use when the patient is light and experiencing pain
fentanyl
effects of propofol on the CNS (3)
- ) decreased cerebral blood flow/volume
- ) intracranial pressure
- ) intraocular pressure