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test 2 GP Flashcards

1
Q

General Anesthesia - how long ago was it introduced? what do we know?

A

General Anesthesia was introduced approximately 150 years ago!

Despite more than 100 years of active research – the molecular mechanisms responsible remains an Unsolved Mystery!

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2
Q

3 major reasons that anesthetic drugs are difficult to study

A

Anesthesia is defined: a change in responses of an “intact animal” to external stimuli- link between observed anesthetic state and the state defined in vivo= very difficult
A wide variety of structurally unrelated compounds can produce clinical anesthesia= suggests multiple molecular mechanisms that can produce clinical anesthesia
Anesthetics work at very high concentrations in comparison to drugs; this implies that they have a very low affinity to the receptor and do not stay bound for long= this makes it much more difficult to observe and characterize than high affinity bonding

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3
Q

What is Anesthesia?

A
  • A collection of “component” changes in behavior or perception
  • The components of anesthetic state: unconsciousness, amnesia, analgesia, immobility, and attenuation of autonomic responses to noxious stimuli
  • Difficulty defining anesthesia as our understanding of the mechanisms of consciousness is amorphous at the present (work continuing to be done)
  • New physiologic markers used to define consciousness being studied
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4
Q

How is anesthesia measured?

A
  • Quantitative measures of anesthetic potency must be measured
  • Minimum alveolar concentration (MAC) = partial pressure of gas at which 50% of humans do not respond to surgical stimulation
  • MAC = Dose: Represents the average response of the whole of the population/ not the response of a single subject
  • End-tidal concentration of gas- provides an index of the “free” concentration of drug required to produce anesthesia; since the end-tidal gas concentration is in equilibrium with the free plasma concentration and BIS monitoring
  • MAC only refers to the concentration of agent. NOT the amount of other adjuncts that we have given
  • BIS monitoring has also become a standard of care
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5
Q

Meyer- Overton Rule:

A
  • More than 100yrs ago Meyer and Overton observed that the potency of gases as anesthetics was strongly correlated with their solubility in olive oil- this idea is referred to as: The unitary theory of anesthesia
  • There is a linear relationship between the oil/gas partition coefficient and anesthetic potency (MAC)- theories regarding protein binding also satisfy the Meyer-Overton Rule
  • Anesthetic agents must disrupt the function of neurons mediating behavior, consciousness & memory
  • Anesthesia alters neuronal communication by:
  • altering neuronal excitability- create a more negative rmp= hyperpolarize the neuron which decreases the action potential
  • synaptic transmission- widely considered to be the most likely subcellular site of general anesthetic action
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6
Q

Unitary theory

A

thinking most drugs act same way… but we know there is not one single way so kind of disproven…

Newer research showing more action at the synapses

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7
Q

•GABA activated ION Channels:

A
  • Many anesthetics potentiate GABA in CNS
  • GABA receptors are probable targets (other- glycine, neuronal nicotinic & 5HT3)
  • Relevant targets for Amidate & Propofol
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8
Q

•Where in the CNS do Anesthetics work?

A
  • Suppress circuits in the spinal cord & brainstem
  • Induce immobility & disrupt autonomic homeostasis

no single site does anesthesia

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9
Q

What we know about anesthesia

A

Anesthetics have powerful and widespread effects on synaptic transmition

Volatile anesthetics directly reduce excitatory synaptic transmission of spinal neurons

Propofol depresses activity in ventral horn neurons via GABAergic mechanism

Isoflurane suppresses interneurons of central pattern generators involved in coordinated movements

Anesthetics can alter descending, afferent, efferent & modulating limbs of reflex arcs for reacting to noxious stimulation

It is clear that all anesthetic acctions cannot be localized to a specific site in the CNS – much evidence allows that different components of the anesthetic state are mediated by actions of disparate anatomic sites

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10
Q

•Autonomic Control:

A
  • Anesthetics exert profound effects on cardiopulmonary & thermoregulatory homeostatic circuitry without autonomic centers in the brainstem & hypothalamus
  • Inspiratory neurons in the medulla drive phrenic motor neurons to activate diaphragmatic contraction
  • Halothane suppresses the spontaneous activity of these neurons
  • Anesthetics also have an effect on the cardiovascular reflexes mediated by nuclei in the brainstem
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11
Q

•AMNESIA

A

the hippocampus is a plausible target for suppression of memory formation

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12
Q

•RETICULAR ACTIVATING SYSTEM (RAS)

A

•Is a diffuse collection of brainstem neurons that mediate arousal

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13
Q

•CEREBRAL CORTEX

A
  • Is the major site for generating awareness of the external environment; primary sensory areas
  • Disruption feedback by anesthetics may contribute to impaired consciousness
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14
Q

****Extubating Criteria****

A
  • EXTUBATION OF THE TRACHEA MUST NOT BE CONSIDERED A BENIGN PROCEDURE
  • Oropharynx/ hypopharynx cleared of secretions
  • 5 second head lift; sustained hand grasp
  • Adequate pain control
  • Minimal end expiratory concentration of inhaled agent
  • Vital capacity > or = 10ml/kg
  • Negative inspiratory pressure > 20cm H2O
  • Tidal volume >6cc/kg•Sustained tetany
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15
Q

Report to PACU

A

Greet RN
Offer patients name
Give procedure while hooking up the O2
Put the pulse ox on first
Attach BP cuff and cycle
Put EKG leads on

List antibiotics given
Amount of narcotic
Patient allergies
Any reactions to meds
Any issues with airway or extubating
Make sure the RN is comfortable with patient and report before you leave

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16
Q

Maintenance of LMA General:

A

Get the patient back breathing
Assist when necessary
Let surgeon know that the patient is ready for injection of local
Have propofol ready in case patient moves with the stimulation
Watch over the drapes and make sure that all is well
The Goal is to have patient breathing throughout with little to no support
No vent; no PSV on vent- learn the right way(Is allowable to use PSV-pro setting with LMA- I am just “old school” Follow the K.I.S.S. plan
Depth of anesthesia matters so they don’t get too light or too deep- it’s a nice way to give anesthesia in this situation
I use the patient’s respiratory rate to guide my narcotic administration

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17
Q

Emergence from LMA General:

A

The patient in this case will likely have a nice local block from the orthopod (Orthopedic Surgeon)
Pain isn’t going to be a big issue
Watch over the drapes because tourniquet tolerance is going to be the only thing that will cause discomfort at the end
Back off on gas and perhaps run 70% nitrous oxide (N2O)
If respiratory rate picks up- It’s ok to work in narcotic
As the dressing is going on- 100% FiO2
Increase your flow rate
Untape eyes
Let patient blow off all gas
Reasonable criteria for LMA removal is when the patient is awake- stay out of trouble
LMA is not stimulating, painful or gag inducing
REMEMBER: 2 types of CRNA …..

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18
Q

LMA Removal:

A

Patient opens eyes you pull out the LMA
I put nasal cannula on the patient
Lift the head of the stretcher and ask if they are comfortable and let patient know that everything went well.
Head to PACU (Post Anesthesia Care Unit)

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19
Q

American Society of Anesthesiologists (ASA)

A

Designed a classification system used to define relative risk prior to conscious sedation and surgical anesthesia
There are many other risk assessments available
This one has shown to be the greatest predictor of perioperative risk
Is the most widely used tool

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20
Q

ASA Physical Status Classification of Patients:

A

Class 1: Normal healthy patient
Class 2: Patient with mild systemic disease (no functional limitations)
Class 3: Patient with severe systemic disease (some functional limitations)
Class 4: Patient with severe systemic disease that is a constant threat to life (functionally incapacitated)
Class 5: Moribund patient who is not expected to survive without the operation
Class 6: Brain-dead patient whose organs are being removed for donor purpose
E: If the procedure is an emergency the physical status is followed by an “E”

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21
Q

NPO

A

nothing per ora; (not allowed to orally consume)

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22
Q

PO

A

per ora; (something ingested orally)

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23
Q

Qd

A

each day

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24
Q

BID

A

twice per day

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25
Q

TID

A

Three times per day

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26
Q

QID

A

Four times per day

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27
Q

Q6h

Q8h

A

Q6h- Every six hours
Q8h- Every eight hours

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28
Q

SAB

A

Subarachnoid block (this is a spinal)

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29
Q

LMA

A

LMA- Laryngeal mask airway

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30
Q

OET

A

OET- Oral endotracheal tube

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31
Q

NET

A

NET- Nasal endotracheal tube

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32
Q

GETA

A

GETA- General endotracheal anesthetic

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33
Q

TIVA

A

TIVA- Total Intravenous Anesthetic

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34
Q

MAC

A

MAC- Monitored anesthesia care (not to be confused with minimum alveolar concentration)

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35
Q

LOC

A

LOC- Level of consciousness

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36
Q

MAP

A

MAP- Mean arterial pressure

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37
Q

CSF

A

CSF- Cerebral spinal fluid

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38
Q

PAW

A

PAW- peak airway pressure

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39
Q

CPAP

A

CPAP- Continuous positive pressure ventilation

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40
Q

EBL

A

EBL- Estimated blood loss

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41
Q

IVGA

A

IVGA- Intravenous general anesthesia

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42
Q

PEEP

A

PEEP- Positive end expiratory pressure

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43
Q

Intrathecal

A

Intrathecal- inside the dura

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44
Q

Epidural

A

Epidural- outside of the dura, In the epidural space (which is a potential space)

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45
Q

O’s

A

Oxygen slang

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46
Q

Gas

A

Gas- commonly the way an anesthesia provider refers to volatile anesthetic agents

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47
Q

GCS

A

GCS- Glasgcow coma scale

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48
Q

HOB

A

HOB- Head of bed

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49
Q

CVA

A

CVA- cerebral vascular accident (stroke)

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50
Q

MVA

A

MVA- Motor vehicle accident

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51
Q

GSW

A

GSW- Gun shot wound

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52
Q

OB

A

OB- refers to obstetrics (usually the unit itself)

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53
Q

ED/ER

A

ED/ER- refers to the emergency department/ emergency room (depending upon your age)

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54
Q

PACU

A

PACU- Post anesthesia care unit

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55
Q

Pre-op

A

Pre-op- Preoperative area

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56
Q

Vt

A

Vt- Tidal volume

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57
Q

BBSE

A

BBSE- Bilateral breath sounds equal (a fast way to chart lung sounds that are clear

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58
Q

IOP

A

IOP- Intraocular pressure

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59
Q

ICP

A

ICP- intracranial pressure

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60
Q

CABG

A

CABG- Coronary artery bypass graft (this patient has had CABG- pronounced cabbage)

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61
Q

CBF

A

CBF- Cerebral blood flow

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62
Q

CMR

A

CMR- Cerebral metabolic rate

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63
Q

MDA

A

MDA- Slang term for anesthesiologists, depending on the Doctor they may find this offensive. No other clinical specialty is defined this way and what if they are a D.O.? Will you refer to them as a DOA?? (please don’t) So understand to whom someone is referring but call them anesthesiologist. If you cannot say that word you are in the wrong field.

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64
Q

•Good pre-op evaluation:

A

Can reduce cost of surgery
Can reduce cancellation rates
Increase resource utilization in the OR (Why do we care?)

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65
Q

Components required in a Pre-op Eval:

A

Review of the medical record

History and physical (pertinent to the surgery)

Appropriate diagnostic tests

Appropriate pre-op consultations

Determine whether the patient’s condition can be improved prior to surgery

Answer all questions

Obtain informed consent

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66
Q

Challenges to preop assessment

A

Pt having outpatient same day
Fast turn over
Limited time to get to know pt
Limited time to create relationship
Limited time to engender trust
Limited time to answer questions

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67
Q

three categories used in forms to rate?

A

Forms are Rated using 3 Categories:
Informational Content
Ease of Use
Ease of Reading

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68
Q

Classification of Urgency of Surgical Procedures

A

EMERGENCY- Life, Limb or Organ Saving; surgery <6hours- examples: ruptured aortic aneurysm; major trauma to thorax or abdomen; acute increase in ICP

URGENT- Conditions threaten life, limb or organ; surgery within 6-12 hours- examples: perforated bowel; compound fracture; eye injury

TIME SENSITIVE- Stable but requires intervention; surgery within days-weeks- examples: tendon; nerve injuries; cancer

ELECTIVE- Procedure planned at patient or surgeon convenience; surgery within 1 year- examples: all other procedures that can be planned in advance

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69
Q

Urgency Classifications:

A

Urgency of surgery must be weighed against the optimization of the patient
Consider the implications of urgency (i.e. Bowel obstruction- Increased risk of aspiration = RSI)
Planned procedures: (Carotid) may require neuro exam & cardiac workup/clearance
Positioning & Necessity of blood products: Can surgery be delayed for optimization or will delay increase morbidity?

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70
Q

Quick Overview of Each System: Barash p. 587

A

Dx & Procedure: Anesthetic/surgical Hx; MH/Adverse Rxn; Airway difficulties
Airway: Known difficulty airway; Sleep Apnea; Teeth; Mallampati; Mouth opening; Chin length; Neck size & Mobility
CNS: Seizures; CVA; Syncope; ICP; Mental status; H/A; Weakness; Spinal cord injury; Psych disorder
Infectious: COVID; HIV; VRE; Flu; TB; Foreign travel
Age/Gender/Height/Weight: Allergies; reactions; Medications (over the counter/herbals and illicit drugs)
CV: Congenital disease; HTN; CAD; CHF; Cardiomyopathy; Valvular disorders; Syncope; Arrythmia; Pacer; PVD; Angina; Dyspnea; Orthopnea; Exercise tolerance
GI/Hepatic: Liver disease; Hepatitis; N&V; GERD; Bowel obstruction; EtOH use
Renal: Insufficiency; Failure; Dialysis
Hematology: Anemia; Coagulopathy; Sickle cell; Chemo; Transfusion Hx
Vital Signs: NPO status; IV access; Invasive monitoring; Advanced directives
Pulmonary: URI/Bronchitis; Pneumonia; Smoking; Asthma; COPD; Cough; dyspnea; Sleep apnea; O2/Inhaler/Steroid use; Pneumothorax; Vent settings; Tube size/depth
Endocrine/Metabolic: DM; Thyroid disease; rheumatoid arthritis; steroid use
Other: Pregnancy; Weeks of gestation; Trauma Hx

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71
Q

PONV? risk?

A

Positive Risk Factors: Female; Hx of PONV or motion sickness; non-smoker; age<50yrs; General vs Regional; Volatile agents; Nitrous Oxide; Post-operative opioids; Duration of anesthesia; Type of surgery (chole; laparoscopic; Gyn)
Conflicting Data: ASA; Menstrual cycle; Anesthesia provider experience; Muscle relaxant reversal
Apfel Risk Score:
No risk factors= 10% chance of PONV; 1 risk factor= 20%; 2 risk factors= 40%; 3 risk factors= 60%; 4 risk factors= 80%

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72
Q

OTC Meds

A

Ephedra: (wt. loss) Tachycardia; HTN; increased sympathomimetic effects with others (arrythmia with digoxin and HTN with oxytocin)
Feverfew: (migraines) PLT inhibitor; Increased breathing risk; rebound H/A with cessation
GBL; BD; & GHB (body building/ wt. loss) Illegal; death; seizures; severe bradycardia; unconsciousness
Garlic: (antioxidant/lowers cholesterol) decreased PLT aggregation
Ginger: (anti-nausea) Potent inhibitor of thromboxane synthetase; Increased bleeding time
Gingko: (blood thinner) Increased bleeding in pts on anti-coags
Ginseng: (energy/ antioxidant) Inhibits PLT aggregation
Goldenseal: (laxative/diuretic) Oxytocic= worsens edema & HTN
Kavakava: (Anxiolytic) potentiates sedatives & hepatotoxicity
Licorice: (Tx of gastric ulcers) HTN; Hypokalemia & edema
St John’s Wort (depression/anxiety) prolongs anesthetic effects
Valerian: (anxiolytic/sedative) potentiates sedative effects of anesthesia
Vitamin E: (slows aging) Increases bleeding in conjunction with anti-coagulants & anti-thrombin meds

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73
Q

Estimated Energy Requirements for Various Activities

A

1 MET: Daily self-care; eat; dress; walk indoors; walk a block or 2 on ground level 2-3mph
4METs: Climb a flight of stairs or walk up a hill; walk on ground level 4mph; run a short distance; heavy work around the house; participate in moderate activities (golf, bowling, dancing, doubles tennis)
>10METs: Participate in strenuous sports like swimming; singles tennis; football; basketball or skiing
Exercise tolerance remains one of the MOST important predictors of Peri-op risk for non-cardiac surgery; also helps define the need for further testing

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74
Q

MOST important predictors of Peri-op risk for non-cardiac surgery; also helps define the need for further testing?

A

Excellent exercise tolerance (even in patients with stable angina) suggests that the myocardium can be stressed without failing

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75
Q

Indications for Further Cardiac Testing

A

Based on an algorithm that integrates clinical hx; surgery specific risk & exercise tolerance
Evaluate the urgency of surgery & appropriateness of formal pre-evaluation
Determine if the pt. has undergone a recent revascularization or CV work up

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76
Q

Using the Systems Approach: Airway

A

AIRWAY-
Evaluate the oral cavity
Evaluate dentition
Thyromental Distance
Assess neck size, tracheal deviation or masses
Ability of the patient to flex and extend the neck and head
Evaluation of trauma patients, patients with severe rheumatoid arthritis or Down’s syndrome requires thorough C-spine eval.
The presence of symptoms of cord compression may require X-ray exam
Modified Mallampati Airway Classification:
1- Full view of soft palate, uvula, tonsillar pillars
2- Soft palate and upper portion of uvula
3- Soft palate
4- Hard palate only

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77
Q

Using the Systems Approach:
LUNGS-

A

LUNGS-
History of tobacco use
Dyspnea
Exercise tolerance
Recent upper respiratory infection
Stridor
Snoring
Sleep Apnea
Physical exam:
Respiratory rate; chest excursion; use of accessory muscles; nail color; decreased breath sounds; wheezing; stridor; crackles

History of asthma
Last time use of a rescue inhaler
Last asthma attack

78
Q

Using the Systems Approach:
CARDIOVASCULAR-

A

Look for s/sx of uncontrolled hypertension and unstable cardiac disease (MI, CHF, Valvular disease; arrhythmia)
Dyspnea
Chest pain
Syncope

Racing rhythms
Irregular beats
Palpitations
SOB
Trouble going up and down a flight of stairs
Presence of unstable angina = High perioperative risk of MI
Periop period= catecholamine surges; hypercoagulable state therefore exacerbates underlying issues such as angina leading to MI
Take BP
Listen to the heart for murmur radiating to the carotids= aortic stenosis
Abnormal rhythm or gallop= heart failure
Presence of Bruits over the carotid= needs further work up for stroke risk

M.A.C.E- Major adverse cardiac events
Low risk procedure= <1% risk of MACE
High risk procedure= >1% risk of MACE
Advanced age = increased risk of MACE and ischemic stroke
Hx of CV disease; DM; Cerebrovascular disease= Elevated risk of MACE
The goal is to identify clinical risk and need of pre-op cardiac testing
The Revised Cardiac Risk Index (RCRI)- assigns peri-op risk using clinical variables
The Revised Cardiac Risk Index (RCRI)-
High-risk type of surgery
History of Ischemic Heart Disease
History of Congestive Heart Failure
History of Cerebrovascular Disease
Pre-operative treatment with Insulin
Pre-operative Serum Creatinine (>2mg/dL)

*Cardiac complications increase with increased risk factors*
Clinical evidence of heart failure:
Dyspnea
Limited exercise tolerance
Orthopnea
JVD
Crackles
Third heart sound
Peripheral edema

Diabetes associated with CV disease:
Diabetes accelerates atherosclerotic disease
Diabetics have a higher incidence of silent MI and myocardial ischemia
Diabetes requiring insulin for treatment is a risk factor in the RCRI
The pre-op ECG should be evaluated for presence of Q-waves
Hypertensive disease:
Hypertension is associated with increased incidence of silent MI
Aggressive treatment of BP is associated with reduction in long-term MI risk
Treat SBP > 150mmHg
Treat DBP > 90mmHg (in pts 60yrs old or >)
* Elective surgery should be delayed for DBP >110mmHg*

79
Q

Importance of Surgical Procedure:
cardio

A

Peripheral procedures are associated with extremely low incidence of morbidity and mortality
Major open vascular procedures are associated with the highest incidence of complications
High risk procedures: major vascular; abdominal; thoracic and orthopedic surgeries

80
Q

cardiovascular importance of exercise tolerance

A

One of the most important predictors of perioperative risk for non-cardiac surgery (helps define the need for further testing and invasive monitoring)
Patients with good exercise tolerance that have stable angina suggests that the myocardium can be stressed without failing
Patients with dyspnea associated with chest pain during minimal exertion= extensive CAD and greater perioperative risk

81
Q

Cardiovascular Patients with Coronary Artery Stents:

A

Early surgery after stent placement = adverse cardiac events (incidence of periop death and hemorrhage)
Delay of non-cardiac surgery for 14 days after balloon angioplasty
Delay of non-cardiac surgery for 30 days after bare metal stent placement
Delay of non-cardiac surgery after drug eluding stents = 12 months

82
Q

CARDIOVASCULAR-
Patients with AICDs:

A

These devices can be impaired by electromagnetic interference (Bovie) during surgery
Review the guidelines for AICDs, pacers and arrhythmia monitors

83
Q

****CARDIOVASCULAR-
Risk of re-infarction under general anesthesia after previous MI:*****

A

MI within 3 months or less = 30% incidence
MI within 3-6 months = 15% incidence
MI greater than 6 months = 6% incidence

*IF re-infarction occurs, the mortality rate is 50%!*

84
Q

Presence of pulmonary complications

A

Post-operative pulmonary complications occur more frequently than cardiac in patients having non-cardiac surgery!
Complications include:
Atelectasis; pneumonia; exacerbation of COPD; pulmonary edema and respiratory failure requiring post-op ventilation
*POST-OP RESPIRATORY FAILURE = MAJOR CAUSE OF M&M*

85
Q

Pulmonary Disease-
Pre-operative pulmonary testing:

A

Pulmonary functions testing (PFT) and chest X-rays (CXR)- proven to have limited benefit in predicting peri-operative respiratory failure and complications
Decreased serum Albumin levels & Increased BUN = increased risk of peri-operative pulmonary morbidity
Predictors-
Open aortic, thoracic and upper abdominal procedures are associated with the HIGHEST RISK of peri-operative pulmonary morbidity
Cranial, vascular and neck surgeries are associated with a HIGH RISK of peri-operative pulmonary morbidity
*These surgeries lead to decreased vital capacity; decreased FRC; and diaphragmatic dysfunction= hypoxemia and atelectasis*

86
Q

Pulmonary Disease-

A

Tobacco-
Increased carboxyhemoglobin levels
Decreased ciliary function
Increased sputum production
Cardiovascular stimulation from Nicotine
* 4-8 weeks of smoking cessation is needed in order to decrease the incidence of post-operative complications* (Airways are very Reactive!!)

87
Q

Asthma

A

Find out the patient’s severity!
current status; frequency of bronchodilator use; frequency of hospitalization (r/t asthma) and steroid use
Consider a “stress dose” if patient takes regular corticosteroids d/t adrenal insufficiency

88
Q

OSA- Obstructive sleep apnea

A

defined as periodic obstruction of upper airway during sleep
Leads to chronic sleep deprivation
Chronic pulmonary hypertension
Right heart failure
* These patients are susceptible to respiratory depressants! Use judiciously!*
OSA Characteristics:
Obesity; Large neck; large tonsils; nasal obstruction; upper airway abnormalities
Questions-
Do you snore?
Do you wake yourself up at night from snoring?
Are you tired in the daytime?
Do you have a hard time breathing?

89
Q

•Endocrine Disease-•Diabetes Mellitus-

A

The majority of diabetics develop secondary disease in one or more organ systems
Increased risk for CAD; HTN; CHF & Peri-op MI
Higher incidence of cerebral vascular, peripheral vascular and renal vascular disease
DM is the leading cause of renal failure requiring dialysis!
Increased peripheral neuropathies= careful positioning
Gastroparesis= theoretical increased aspiration risk
Stiff joints d/t glycosylation of proteins (could affect airway)
Thorough H & P
Draw blood glucose on arrival, hgbA1c; Lytes; creatinine and ECG
Type 1 Diabetics= hgbA1c <7.5%
Type 2 Diabetics= hgbA1c <7% - or abnormal lytes or ketonuria = DELAY ELECTIVE SURGERY!!
*optimize these patients then bring them back*
Perioperative sugar management-
The periop experience comes with increased serum glucose d/t stress (cortisol and catecholamine release)
Glycemic control decreases morbidity, infection rate, stroke incident and improves wound healing
Goals- Cardiac surgery= maintain sugar 80-100 mg/dL
Goals- non-cardiac surgery= maintain sugar <200mg/dL
Hold oral hypoglycemic meds the day of surgery
Continue insulin (consider half dose)

90
Q

Endocrine Disease-
Thyroid/ Parathyroid Diseases:

A

Screen for s/sx of hyper/hypothyroidism-
Hypo= hypothermia; hypoglycemia; hypoventilation; hyponatremia & heart failure
Hyper= THYROID STORM- tachycardia; A-fib; CHF; tremor; muscle weakness & anemia

*enlarged thyroid may create airway difficulty*
Hyperparathyroidism= hypercalcemia (draw Ca++)
s/sx= weakness; lethargy; headache; insomnia; apathy; bone pain & epigastric pain

91
Q

Endocrine Disease-
Adrenal cortical suppression:

A

Be suspicious of those on long term steroid use (Cushing’s- moon face; skin striation; truncal obesity & HTN)
Make sure that they get a stress dose if steroids were taken for one month or greater within the last 6-12 months (if more than a minor procedure)
Max dosing= 100mg hydrocortisone IVP before surgery then q8h x 1 day then 50mgIVP— highly debated*

92
Q

Endocrine Disease-
Renal Disease:

A

Assess electrolytes
Make patient euvolemic prior to induction (likely dry if hemodialysis recently)
Be mindful of meds metabolized by kidneys

93
Q

Endocrine disease- Liver disease

A

Coagulopathy (know levels before regional)
Decreased plasma proteins- affects drug binding
Consider labs if increased ETOH history

94
Q

•Laboratory Test Recommendations-

CBC

A

CBC- extremes of age; liver or kidney disease; anticoagulant use; bleeding; hematologic disorders; malignancy; type & invasiveness of surgery

95
Q

Lab testing Coags

A

COAGS- liver or kidney disease; bleeding disorder; anticoagulant use; chemotherapy

96
Q

Lab testing serum chemistry

A

SERUM CHEMISTRY (glucose, lytes, renal & liver function)- liver or kidney disease; DM; CNS disease; Endocrine disorder; Elderly; Malnutrition; type & invasiveness of surgery

97
Q

Lab testing

CXR

A

CXR- pulmonary disease or clinical findings (r/o pneumonia or pulmonary edema); unstable cardiovascular disease; type & invasiveness of surgery

98
Q

Lab testing ECG

A

ECG- CV disease or clinical findings; pulmonary disease; type & invasiveness of surgery

99
Q

Lab testing pregnancy test

A

PREGNANCY TEST- possible pregnancy (child bearing years)
everyone

100
Q

Go forward with surgery?

A

Are risk factors modifiable?
Will delaying the procedure add to peri-op risk or morbidity?
What can we do in the peri-op period to decrease this patient’s risk?
Do we have enough information to make an informed decision?

101
Q

•Aspiration Risk

A

Emergency surgery
Inadequate (light) anesthesia
Abdominal pathology
Obestity
Opiates
Neuro deficits
Lithotomy
Difficult intubation
Reflux
Hiatal Hernia

102
Q

****Aspiration Risk:
Fasting Times-****

A

Clear liquids= 2 hour minimum
Breast milk= 4 hour minimum
Infant formula= 6 hour minimum
Non-human milk= 6 hour minimum
Light meal= 6 hour minimum

103
Q

Aspiration Risk:
Medications-

A

Bicitra: Increases gastric pH in 100% of the cases it is used – Highly effective antacid
Famotidine: Increases gastric pH
Reglan: Increases gastric emptying (obese; pregnant; diabetics; trauma & emergency surgery)

104
Q

Pre-anesthetic Screen

A

Diagnosis/Procedure
Anesthetic/surgical Hx
MH/Adverse rxn
Airway difficulty
Airway
Difficult?
Sleep Apnea
Exam: teeth; mallampati; mouth opening; chin length; neck size and mobility
CNS
Stroke; mini-stroke; seizures; numbness; tingling; weakness
Altered mental status; headaches; neuromuscular disease; spinal cord injury
Psych disorders: anxiety, depression.. Etc..
Infectious
If/When did you have COVID-19; HIV; MRSA; VRE; influenza; TB; foreign travel- Any Sequalae

Age/ Gender/ Height/ Weight
Allergies- adverse med reactions
Medications
Over the counter meds (herbals, illicit drugs)
Cardiovascular
Congenital heart disease; hypertension; coronary artery disease; heart failure; cardiomyopathy; valvular disease; syncope; arrhythmia; pacer; ICD; vascular disease
Chest pain, SOB; racing rhythms; irregular beats; palpitations; able to go up and down stairs without SOB
GI/ Hepatic
Liver disease; reflux (GERD, Hiatal hernia)
Bowel obstruction
Alcohol use
Renal
Insufficiency; failure; dialysis
Hematology
Anemia; coagulopathy; sickle cell; chemo; transfusions (do this in lay terms)
Vital Signs
NPO status; IV access; invasive monitors; advanced directives
Pulmonary
URI; bronchitis; pneumonia; recent cough or cold; asthma
- When’s the last time you used a rescue inhaler?
Have you ever been hospitalized for your breathing?
Endocrine/Metabolic
Diabetes; thyroid; rheumatoid arthritis; steroid use

105
Q

Legalities of Negligence in Patient Positioning

A

Problems arising from positioning such as peripheral neuropathies injuries fall under the doctrine “Res ispa loquitur” “the thing speaks for itself”
This implies the injury sustained is so evident that it would not have occurred without negligence from someone else
Patient only has to prove that there was an injury . . .
This is why documenting pre-existing issues is so important

106
Q

Types of Nerve Injury Following General Anesthesia

A
107
Q

Goal of close claims project

A

•The goal of the Anesthesia Closed Claims Project is to identify major safety concerns, patterns of injury and strategies for prevention to improve patient safety by anesthesiologists working in pain management, operating rooms, labor floor, remote locations and critical care.

108
Q

Perioperative Neuropathy at night…

A

Perioperative neuropathy or soft tissue injury when sleeping naturally
Wakes us up
Hip starts to hurt so we wake up and shift to the other side
We can adjust ourselves when something gets uncomfortable
Both consciously or unconsciously move and reduce the tissue stretch and compression forces that caused the symptoms

109
Q

Mechanisms of Soft Tissue Injury

A

**Tissue stretch and compression** are most commonly associated with positioning-related problems in anesthetized or sedated patients
Stretch (especially > 5% of resting length):
Kinks or decreases lumens feeding arterioles and draining venules
Direct Ischemia from reduced arteriole blood flow
Indirect ischemia from venous congestion
Compression: (neuropraxia or axonotmesis)
Direct pressure reduces local blood flow and disrupts cellular integrity
Results in tissue edema, ischemia and possibly necrosis
Padding

110
Q

Mechanisms of Positioning Injury

A

Don’t really know for sure
Perioperative Inflammatory Responses
Inflammatory neuropathy
Microvascular neuropathies
Autoimmune disease/Viruses/immunosuppression
Radiation-induced
Systemic inflammation from drugs

111
Q

Goals of Proper Positioning

A

Gives the surgical team a clear view of the surgical site
Provides the best access to the surgical site for the surgeon
Gives anesthesia the best position for the optimal administration of drugs
Can reduce bleeding before/during/after the surgery
Decreases the risk of pressure and nerve related injuries
Can prevent or reduce risk of respiratory problems (especially when anesthesia is involved)
Prevents/reduces risks associated with circulatory issues

112
Q

Team Member Responsibilities

A

Surgeon
- Optimal procedural exposure
Anesthesia
- Physiologic requirements (ABC’s)
-Ongoing assessment
-Ensure patient safety
Nursing
-Safe transfer
-Use of adequate padding and positioning aids
- Ongoing assessment

113
Q

Key Points Associated with Positioning

A

A through assessment of risk factors for complications related to positioning should be an interral part of the preoperative evaluation
A history of surgeries related to positioning. Knee back hip of neck surgery may need special positioning considerations

114
Q

Basic Principles of Positioning

A

Shared responsibility
Must document every change and how you protected patient
If head, neck or whole body moves must recheck and document breath sounds
Hypotension biggest physiologic consequence of position changing
Patients are unconscious and relaxed – can often be put in positions not tolerated.

115
Q

Common Perioperative Neuropathies

A

**Ulnar Neuropathies** most common
Brachial Plexopathies
Median Neuropathies
Radial Neuropathies
Lower Extremity Neuropathies

116
Q

Ulnar Neuropathy

A

Most COMMON perioperative neuropathy
Key factors associated with ulnar neuropathy:
Direct extrinsic nerve compression (often medial aspect of elbow)
Intrinsic nerve compression (associated with prolonged elbow flexion)
Inflammation
Male, high BMI, older, prolonged postop bed rest

117
Q

Timing of postoperative symptoms

A

Most develop during postoperative period
Studies suggest that those patients that develop ulnar neuropathy experience their first symptoms at least 24-48 hours postoperatively
Medical patients can also develop ulnar neuropathies during hospitalization

118
Q

Anatomy and Elbow flexion

A

Ulnar nerve passes behind medial epicondyle and under the aponeurosis that holds the two muscle bodies of the flexor carpi ulnaris together
Proximal edge of aponeurosis (cubital tunnel retinaculum) is thick, especially in men
The retinaculum stretches from the medial epicondyle to the olecranon
Flexion of the elbow stretches the retinaculum and puts a lot of stress on the nerve as it passes underneath

119
Q

Impact of elbow flexion

A

Ulnar nerve is the only major peripheral nerve in the body that always passes on the extensor side of a joint…….. the elbow!
All other major peripheral nerves primarily pass on the flexion side
Peripheral nerves start to lose function and can develop ischemia when stretched >5% of their resting length
>90 (110) degree elbow flexion stretches the ulnar nerve

120
Q

Positioning the ulnar nerve

A

Abduct less than 90 degrees
Supinate the arm
Use padding

121
Q

Outcomes of Ulnar Neuropathy

A

About 40% of sensory-only ulnar neuropathies resolve within 5 days
About 80% resolve within 6 months
Only a few combined sensory and motor ulnar neuropathies resolve within 5 days
About 20% resolve within 6 months and most result in permanent motor dysfunction and pain
Compression or stretch injury

122
Q

Ulnar nerve injury

A

Compression at nerve between table and medial epicondyle
Prevent by supination, avoid hypotension and hypoperfusion
Pad arms properly
Manifested by *inability to abduct the 5th finger
Weakness/ atrophy of hand muscles *“claw-hand”*
Numbness, tingling or pain in the lateral aspect of the hand on the side of the ulnar nerve injury

123
Q

Other contributing factors for Ulnar Neuropathy

A

Patient characteristics
prolonged bedrest and high body mass index
Men: 1.5 times larger tubercle of the coronoid process, less adipose tissue, thicker cubital tunnel retinaculum

Abnormal ulnar nerves before surgery (Contralateral neuropathy)
Poorly formed fibrotendinous roof of the cubital tunnel
External compression in the absence of stretch

124
Q

Brachial Plexus Injury

A

Most common is patients undergoing sternotomy (especially those with internal mammary artery mobilization)
Patients in prone and lateral have a higher risk than supine
Things to think about:
Brachial plexus entrapment
Prone positioning
Anatomy of shoulder abduction

125
Q

Brachial Plexus Entrapment

A

Prone and lateral position patients
Brachial plexus can become entrapped between compressed clavicles and rib cage
Prone position
Better if arms can be tucked
Some patients can have somatosensory-evoked potential changes when their arms are abducted (surrender position)

126
Q

Causes of injury to brachial plexus

A

Shoulder braces may compress nerve roots and stretch the plexus
Turing the head (unconscious patient) may stretch the brachial plexus
Spreading the sternal retractor causes the clavicle and rib to pinch the plexus. Unilateral retraction may cause stretching of the nerves.

127
Q

Brachial plexus pic

A
128
Q

Anatomy of shoulder abduction

A

Abduction > 90 degrees places the distal plexus on the extensor side of the joint and possibility of stretching the plexus
Goal is to avoid abduction >90

129
Q

Brachial plexus injury - occurs from

A

Excessive external rotation or abduction of arm
Avoid > 90 degree abduction
Avoid arm falling off of table!
Watch lateral head rotation
If prone watch flexion and abduction of arms overhead
Lateral position requires an axillary (chest) roll which avoids compression of humerus into axilla

130
Q

Long Thoracic Nerve Dysfunction

A

Scapular winging
Serratus anterior muscle that is supplied by the long thoracic nerve that branches immediately from C5-C7, sometimes C8
Long thoracic nerve palsy allows the dorsal protrusion of the scapula
Traumatic in nature
Viral/inflammatory?

131
Q

Nerve Injury - what happens

median, axillary, ulnar, musculocutaneous, radial

A

Manifestations depend on which nerves are injured in the plexus:
Median – “Ape hand” deformity, inability to oppose thumb - Muscular men with large biceps are susceptible to median nerve injury if the arm is fully extended during surgery

Axillary – inability to abduct the arm
Ulnar – “Claw hand” deformity
Musculocutaneous – inability to flex forearm
Radial – wrist drop

132
Q

Axillary Neurovascular Injury

A

Abduction of the arm on the arm board > 90 degrees
Head of the humerus into the axillary neurovascular bundle
Compression and stretch injury
Compression or occlusion of vessels with decreased perfusion
Mastectomy

133
Q

Median Neuropathies

A

Mostly in men between 20 and 40 years old
Men with large biceps and decreased flexibility
Prevents complete extension at the elbow
Creates a shortening of the median nerve over time
Usually motor dysfunction and don’t readily resolve
Around 80% with motor dysfunction are still there 2 years after initial onset
IVs in the antecubital area
Things to think about:
Stretch of the nerve: nerves become ischemia if stretched >5% of their resting length which can kind penetrating arterioles and exiting venules decreasing perfusion pressure
Arm support

134
Q

Arm Support

A

When muscular men are anesthetized, their arms are fully extended at the elbow and placed on armboards
Full extension of the elbow stretches chronically contracted median nerves and promotes ischemia (at the level of the elbow)
Very important to support/pad the forearm and hand to prevent full extension

135
Q

Radial Neuropathies

A

More common that median neuropathies
Injured more often by direct compression (in contrast to median nerve injury due to stretch)
Radial nerve injury is usually compression of the nerve in the mid-humerus area (arising from roots C6-8 and T1)
Things to think about:
Surgical retractors: compression of radial nerve by bars used to hold abdominal retraction holders
Lateral position (impinged by overhead arm boards)
Unsupported arms/ poles/ repeated cycling of the BP cuff

136
Q

The Third Amigo….

A
137
Q

radial nerve pic

A
138
Q

Radial Nerve Injury

A

Can be injured if compressed against spinal groove of humerus and other object (ie. Either screen or excessive cycling NIBP
Symptoms include wrist drop, weakness of abduction of thumb and loss of sensation in web space between thumb and index finger.

139
Q

Lower Extremity Neuropathies

A

Common peroneal
Sciatic nerve
Obturator nerve
Lateral femoral cutaneous nerve
Femoral nerve

140
Q

do you need to be careful positioning the hip?

A

Great care must be exercised when placing the hip in unusual positions. Excessive flexion or abduction can injure the lateral femoral cutaneous or obturator nerves respectively.

141
Q

Obturator Neuropathy

A

Hip abduction >30 degrees can cause strain on obturator nerve
Obturator passes through the pelvis and out the obturator foremen
Excessive hip flexion of thigh can cause compression
Excessive traction in abdominal Sx
Motor dysfunction is common
Inability to adduct the leg with decreased sensation over the medial side of the thigh

142
Q

Lateral Femoral Cutaneous Nerve

A

Prolonged hip flexion >90 degrees can cause ischemia
One third of the nerve’s fibers pass through the inguinal ligament as it passes through the thigh (originates at L2-3)
Hip flexion >90 degrees causes lateral displacement of the anterior superior iliac spine and stretch of the inguinal ligament
Nerve fibers are compressed by the stretch and can become ischemic and dysfunctional
This nerve carries ***only sensory fibers** so no motor disability occurs
But can have disabling pain and dysesthesias of the lateral thigh

143
Q

Sciatic Nerve

A

Can be stretched with external rotation of the leg
Sciatic and its branches (common peroneal and tibial nerves) cross the hip and knee joints and are stretched by hyperflexion of the hips and extension of the knees

144
Q

Peroneal Neuropathy

A

Usually associated with direct pressure of the lateral leg, just below the knee, where the peroneal wraps around head of the fibula
Injured by leg holders (candy cane) that hold the leg and foot
Impinge the nerve around the head of the fibula
Can cause prolonged foot drop and trouble ambulating

145
Q

Saphenous Nerve Injury

A

May be injured when the medial tibial condyle is compressed by leg supports
May be injured during difficult forceps delivery or by excessive flexion of the thigh to the groin

146
Q

Physiological changes related to change in body position

A

Most changes are related to gravitational effects on cardiovascular and respiratory systems
Changes in position redistribute blood within the venous, arterial, and pulmonary vasculature
Pulmonary mechanics also change with varying body positions

147
Q

Cardiovascular changes with Positioning

A

Changing from erect to supine increases venous return and stroke volume
Parasympathetic stimulation regulate heart rate and contractility to adjust to increased preload
Obesity (wedge under Rt hip), pregnancy, and abdominal tumors can reduce venous return (preload) when in the supine procedure

148
Q

Starling’s Law

A

The Frank-Starling law states that the force or tension developed in a muscle fiber depends on the extent to which the fiber is stretched. In a clinical situation, when increased quantities of blood flow into the heart (increasing preload), the walls of the heart stretch.

149
Q

Pulmonary changes with Positioning

A

In supine position, functional residual capacity and total lung capacity are reduced due to changes to the diaphragm
This is exaggerated in obese patients
Anesthesia and muscle relaxants further reduce these volumes due to diaphragm position with relaxation
Trendelenburg position also reduces lung volumes
Any position that limits movement of the diaphragm, chest wall or abdomen may increase atelectasis and intrapulmonary shunt

150
Q

Common Surgical Positions list:

A

Four basic surgical positions:
Supine
Prone
Lithotomy
Lateral
Variations
Trendelenburg
Reverse Trendelenburg
Fowlers
Jackknife
High and low Lithotomy

151
Q

Supine

A

Patient on back
Arms on arm boards or tucked
Check orientation of arm (arms < 90 degrees)
Make sure arm is supinated (palm up)
Place additional padding under elbow if able
Check fingers
Check IV lines and SaO2 probe

FRC is decreased by 20%
Abdominal contents limit movement of the diaphragm
Decreased muscle tone from GA
Small airways close sooner  hypoxia
VQ changes cause shunting hypoxia
Obesity and pregnancy problems
Compression of the IVC
Pressure on occiput alopecia
Pad back of head
Check often in long cases

Keep hips and knees slightly flexed
Blanket/ pillow under knees
Legs uncrossed
Heels, occiput and elbows padded
Cervical, thoracic and lumbar spines should be in straight alignment
Arms
If at side must be padded and tucked
Watch fingers !!!!!
On arm boards
Padded, palms up (supinated) less than 90 degree angle

152
Q

Complications of Supine

A

Peripheral neuropathies which can occur in any position
Backache
Ischemic pressure injuries
Pressure Alopecia
Prolonged compression of hair follicles produce hair loss
Pain and swelling where the occiput has been supporting weight in the head down position
Associated with tight face mask straps, hypotension and hypothermia
Pressure-Point issues
Hypothermia and vasoconstrictive hypotension
Heels, sacrum and elbows

153
Q

Arm Restraints

A

Restraint too tight
Pressure compresses the anterior interosseous nerve (branch of the median nerve) in the upper forearm
Can resemble compartment syndrome in the lower extremity

154
Q

Nerve Injury and Supine Position

A

Brachial plexus neuropathy
Sternal retraction
Long Thoracic Nerve Injury
Axillary trauma from humeral head
Radial nerve compression
Median Nerve Dysfunction
Ulnar Nerve Neuropathy
Back pain
Compartment syndrome

155
Q

Lateral Decubitus

A

Positioned on side often with assistance of supports or bean bag
Arms parallel and padded
Maintain good anatomical alignment
Pillow between legs and feet
Keep bottom leg flexed to stabilize the trunk
Chest roll placed
Check radial pulse of dependent arm

156
Q

Chest Roll

A

Support placed caudad to the downside axilla
Axillary Roll???
Lifts the thorax enough to relieve pressure on the axillary neurovascular bundle
Helps prevent decreases in blood flow to the hand and arm
Questionable
Decrease shoulder pain after postop

157
Q

Common Peroneal Injury and Lateral Position

A
158
Q

Flexed Lateral Decubitus

A

Flexion should be under the iliac crest
Chest roll
Neck neutral
Pillow between knees and flexed
Padding under ankles/feet

159
Q

Flexed Lateral Position

A

Flip the table so the flank and thorax are horizontal
Feet/legs below the atria causing pooling of blood
Lumbar stress
Thoracotomy
Not very common

For Kidney surgery:
Lateral jackknife with elevated kidney rest

160
Q

Lateral decubitus

A

VQ mismatching:
Dependent lung:
Underventilated
More perfusion
Nondependent lung:
Overventilated
Less perfusion
Causes incr. VQ mismatching hypoxia

161
Q

Lithotomy

A

Patient is supine with arms extended laterally <90 degrees
Each lower extremity is flexed at the hip (about 90 degrees) and knees bent parallel to the floor
Extremities should be elevated and lowered slowly and together
Seen most often in GYN and Urology cases
Hip flexion >90 degrees can increase stretch of the inguinal ligaments

162
Q

Lithotomy Stirrups

A

Various types of stirrups
Candy cane
Allen stirrups
Knee cradles
Move legs at same time when positioning patient in and out of lithotomy

163
Q

Lithotomy Positions low high exaggerated

A

Low:
About 30-45 degrees
Reduces perfusion gradients
High:
Suspend the patients feet high with stirrups
Patient’s legs almost fully extended on the thighs flexed 90 degrees or more on the trunk
Significant uphill gradient for arterial perfusion to the feet
Avoid hypotension
Stretch of sciatic nerve
Compression of femoral canal by inguinal ligament
Exaggerated
Pelvis flexed ventrally on the spine, thighs forcibly flexed on trunk and lover legs aimed skyward
Associated with compartment syndrome

164
Q

things to think about Lithotomy

A

Can auto transfuse up to 500 cc of blood
Remember this will shift back when legs go down and can cause a decrease in BP
Can impair ventilation due to upward pressure
More prominent in obese pt’s
Nerve injuries !!!!
Most common problem with lithotomy
Injuries: Sciatic, common peroneal, femoral, saphenous and obturator
Hand injury (fingers in bed)

165
Q

Common Peroneal Nerve

A

Common peroneal nerve damage
Occurs from compression of lateral aspect of fibula head (improper padding against stirrups)
FOOT DROP
Elevate and flex simultaneously
Avoids stretching of one side of the nerve
> 4 hrs in lithotomy increases risk of injury
Ischemia, edema to skin and muscles

166
Q

Femoral Nerve

A

Femoral nerve injury
Excessive angulation of the thigh on the abdomen
Excessive traction during abdominal Sx
Decreased flexion of the hip
Decreased extension of the knee
Loss of sensation over superior aspect of the thigh and medial or anteromedial side of the leg

167
Q

acute compartment syndrome of hand

A

In the immediate postoperative period, she developed compartment syndrome of the right hand that required multiple fasciotomies and multidisciplinary management by plastic surgery, orthopedics, and rehabilitation medicine.

Acute compartment syndrome of the hand is a potentially devastating and infrequent condition observed after trauma, arterial injury, or prolonged compression of the upper limb

168
Q

Compartment Syndrome

A

Perfusion to an extremity is inadequate
Characterized by ischemia, hypoxic edema, elevated tissue pressure within fascial compartments and extensive rhabdomyolysis
Lateral position(arm) and lithotomy (legs)
Associated with:
Systemic hypotension and loss of driving pressure to the extremity (elevation)
Vascular obstruction from excessive flexion, knee or pelvic retractors
External compression from straps
Lithotomy for >5 hours common factor

169
Q

Prone Position

A

Used for posterior fossa of the skull, posterior spine, buttocks and perirectal and lower extremities (Achilles)
Head neutral
ET tube placement and patency
Check bilateral eyes/ears for pressure points
Head turned
Check dependent eye/ear ETT placement
Be aware of potential vascular occlusion
Arms at side or “surrender position” < 90 degrees to prevent stretching of brachial plexus

170
Q

Supine to Prone

A

Need multiple people to assist
Disconnect all lines/monitors if possible
Patient is log rolled gently so there are no abnormal movements or twisting of body parts
Using normal ROM arms are placed beside the pt’s head or brought down to the sides of the body
Chest rolls from below clavicles to iliac crest
Provide adequate lung expansion and help alleviate pressure on abdomen
Protect male genitalia and female breasts
Full monitoring reinstituted ASAP, ET tub positioning reconfirmed

171
Q

Prone

A

Pillow under lower legs and ankles help flex knees and prevent pressure on toes
Head on special pillow with cut out area free of pressure on face/eyes
Head positioned to side may impair drainage on one side or neutral
Elastic stockings and active compression to minimize pooling of venous blood
Cardiac:
Compression of abdominal viscera
Pooling of blood in extremities
Decreased preload, CO, BP, SV
Increased SVR and PVR
Pulmonary
Decreased total lung compliance
Increased work of breathing
ETT dislodgement
Other
Check and document face and eye free of pressure every ? min
Blindness from retinal ischemia
ION- Ischemic optic neuropathy
Corneal abrasions

172
Q

Reverse Trendelenburg

A

Cholecystectomy, head and neck procedures
Shifts the abdominal contents caudad
Prevent patients from slipping off the table
May have hypotension may result in decreased venous return and perfusion to brain
Facilitates exposure, aids in breathing (increased FRC)

173
Q

Trendelenburg

A

Causes further pressure upwards on diaphragm from abdominal contents and further decreases lung expansion
Increases ICP by decreasing venous drainage
Increased IOP (pt with glaucoma)
Activation of baroreceptors
^ pressure; ^ baroreceptor discharge; inhibits systemic vasoconstriction(SNS) & enhances vagal tone
Increased risk of aspiration
Mendelson syndrome: aspiration of > 25cc of gastric contents with a pH of < 2.5

174
Q

What are the physiologic effects and risks associated with Trendelenburg position?

A

Further increases translocation of blood to central compartment (along with lithotomy)
Intracranial and intraocular pressure increases
What should you think about before extubation?
Facial and upper airway edema (Can the patient breath around the ET tube with the cuff deflated)
What pulmonary changes can occur?
Decrease in pulmonary compliance, FRC and vital capacity
Shoulder braces and brachial plexus injury

175
Q

What injuries can occur to the eye?

A

What is the most common injury to the eye?
Corneal abrasion
What are some other injuries to the eye?
Chemical injury, direct trauma (pressure and crush), blurred vision

176
Q

How does the head position affect the position of the ET tube?

A

Flexion of the head may move the endotracheal tube toward the carina; extension moves it away from the carina.

A general rule is that the tip of the endotracheal tube follows the direction of the tip of the patient’s nose.

Sudden increases in airway pressure or oxygen desaturation may be caused by mainstem bronchial intubation.

177
Q

Sitting (Beach Chair)

A
178
Q

Awake Vs Anesthetized in Sitting Position

A

Awake-

MAP, SV, CO, PaO2 all decrease
Alveolar-arterial oxygen gradient and pulmonary and vascular resistance all increase
An autonomic response helps compensate for the above by increasing SVR by up to 50-80%
Cerebral perfusion pressure decreases by about 15%

179
Q

Awake Vs Anesthetized in Sitting Position

A

General Anesthesia:

  • The autonomic response is inhibited by general anesthesia causing vasodilation and decreased CO
  • GA causes vasodilation, myocardial depression, and impaired venous return that further impairs cerebral blood flow
180
Q

More Physiologic Changes in Beach Chair

A

Flexion of the head may obstruct the internal jugular and cause cerebral venous engorgement or hypoperfusion (swelling in the face, eyes)
Extension of the head can impair cerebral blood flow causing cerebral ischemia, obstruction of ET and pressure on the tongue

181
Q

****Cerebral Perfusion Pressure (CPP)****

A

Cerebral vasculature dilates and constricts to maintain constant blood flow to the brain
CPP = MAP – ICP (or CVP)
Autoregulation occurs when MAP in between 50 and 150 m Hg
Poorly controlled HTN the curve is shifted higher to the right

182
Q

CPP and BP in Sitting Position

A

Supine: BP in arm is similar to CPP in the absence of ICP
Beach chair: MAP and BP in the arm is higher than Cerebral perfusion
Monitored at external auditory meatus (represents the base of the brain) which is about 20 cm above the heart (15 mm Hg difference)
Cuff site (blindness and stroke due to inaccurate BP )
1 mm Hg decrease/1.35 cm height (20 cm ~ 15 mmHg change)

183
Q

Sitting Position Complications

A

Potential complications from sitting position
Venous air emboli
Need to take measures to detect and extract VAE
Hypotension (fluids, vasopressors, decrease agent)
Brainstem manipulations resulting in hemodynamic changes
Risk of airway obstruction
Decrease venous return (stockings or compression devices)
Macroglossia (avoid chin against chest)

184
Q

Midcervical Tetraplegia

A

Hyperflexion of the neck, with or without rotation of the head
Stretching of the spinal cord resulting in compromise of the vasculature of the midcervical region
Paralysis below the general level of the 5th cervical vertebra
Sitting position
Prolonged head flexion for intracranial surgery in the supine position

185
Q

Sitting Position……..VAE

A

VAE: venous air embolism
Caused by open venous system above level of the heart
Atmospheric pressure > venous pressure and vein sucks air in
Detection by listening to heart sounds with Doppler at R 2nd intercostal space
A sudden decrease in CO2, hypoxia, arrhythmias, hypotension and a millwheel murmur (usually a late sign)

186
Q

Venous Air Embolism Treatment

A

Stop the problem
Flood area with water if necessary
100% O2 and Stop N2O
Aspirate from CVP
Durant’s position
Vasopressors
Get ready to do CPR

187
Q

Face Masks

A

Can cause pressure damage over nose
Facial nerve damage from fingers over mandible
Face straps can cause injury or even necrosis to face, ears and eyes and alopecia

188
Q

Visual Injuries

A

Corneal abrasions are the most common
Chemical irritation from preparation solutions
Direct trauma from face mask
Pressure from the hands while intubating
Pressure effects from lateral and prone position
Poor eye taping techniques
Blindness more rare
Etiology probably ischemic optic neuropathy
Large volume blood loss
Prolonged hypotension
Duration of surgery
Prone or lateral position
Edema
Patient’s at Risk
DM
Smokers
Obese
ETOH abuse
Anemic
HTN
Consent ALL Patient’s at Risk

189
Q

Potential Etiology of POVL

A

Acute venous congestion of the optic canal
Wilson Frame
Head is lower than the heart
Obesity can increase intraabdominal pressure in prone patients
Long durations
All the above can contribute:
to venous congestion in the optic canal
reduction of optic nerve perfusion pressure

perioperative visual loss. Thought about possibility of visual loss. People need to know it’s a possibility during consent… prone spine surgery- does pt want to know about it 80% of pts want to know… Closed practice claims 5% are for the eye- ( most common is corneal abrasion.
ION ischemic – neuropathy .8 % and corneal is just 1%.
Done surgery if only ive known about blindness I would not have done the procedure. Had to describe it – who will bear responsibility – surgeon cant be pt didn’t understand and anesthesia would check to make sure they understand if didn’t would not start till pt understood. Rare event ION place extreme stroke even death above vision.

190
Q

Ways to Help prevent eye?

A

Reduce venous congestion in the optic canal
Keep head above the heart or at the same level
Colloids vs Crystalloids
Reduce intra-abdominal pressure
Limiting duration of surgery

191
Q

Prevention is the best practice

A

Avoid positions that permit stretching of the nerves
Avoid pressure to areas that carry nerves prone to injury (ulnar cubital tunnel, peroneal)
Padding and support should distribute weight over wide areas
Patients position should be neutral whenever possible
Anesthesia and muscle relaxants increase malposition injuries
Extremes of weight is obviously a risk
ASK the patient what is comfortable

192
Q

Which patients should we position before inducing anesthesia?

A

Patients with a history of back pain or previous surgery
Patients with history of knee and hip arthroplasty
Neck pain
Shoulder pain
Rheumatoid arthritis
Anyone that complains of pre-existing injury….
ALWAYS CHART WHAT YOU DID (patient positioned for comfort in stirrups before induction, neck neutral, hands padded per patient request and comfort)

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