Potential hazards in the OR what

anesthetic gas levels in the or

radiation exposure

fire

noise

infectious hazards

stress

substance abuse

what is the national Institute for occupational safety recommendation for gas exposure?

Not more than 2 ppm for volatile gases

not more than 25 ppm for nitrous oxide.

Potential hazards in the OR

anesthetic gas levels in the or

radiation exposure

fire

noise

infectious hazards

stress

substance abuse

3. What is the number one reason for anesthesia related morbidity and mortality?

Lack of or improper airway management.

(Broken teeth, aspiration, airway trauma, unexpected tracheostomy, brain injury and

cardiopulmonary arrest).

4. What is the division point between the upper and lower airway?

cricoid cartilage.

5. The nasal mucosa supplied by the branches of which arteries?

Maxillary (sphenopalatine branch), ophthalmic and facial (septal branch).

6. What problem can happen that may allow direct communication with the cranium? What are some of the complications associated with this problem?

Disruption of the cribriform plate due to trauma or head injury may allow direct communication with the cranium. Positive pressure ventilation can drive bacteria or foreign material into this area leading to meningitis or sepsis. Nasal airways, nasogastric tubes and nasal tracheal intubation can be inadvertently introduced into the subarachnoid space.

7. How is the nasal mucosa innervated?

The anterior ethmoidal nerve, a branch of the ophthalmic division of the trigeminal nerve, supplies the anterior third of the septum and lateral wall. The maxillary division of the trigeminal nerve via the sphenopalatine ganglion supplies the posterior two thirds of the septum and the lateral wall.

8. Sympathetic innervation and inhibition results in what in the nasal mucosa?

Sympathetic innervation results in vasoconstriction and shrinkage of the nasal tissue. Depression or inhibition of the sympathetic nervous system produces engorgement of the nasal tissues increasing the likelihood of bleeding with manipulation.

9. What does general anesthesia due to the nasal mucosa?

General anesthesia delivers dry air and inhibits the sympathetic nervous system!

10. How much airway resistance is accounted for through the nose?

2/3 of the airway resistance occurs due to the nose.

11. The oral cavity is separated from the nasal cavity by what?

The hard and soft palates. The hard palate is stationary. The soft palate covers the posterior one third of the oral cavity. The soft palate rises during eating to prevent food or liquid movement into the nose. Age, obesity and other conditions causes this structure to stretch and become more mobile. As we sleep or when we paralyze a patient, the soft palate falls back against the nasal passage and blocks air movement causing symptoms of sleep apnea.

12. Name the structures in the mouth and described how they contribute to airway

obstruction?

13. The pharynx is divided into three parts what are they?

The nasopharynx, oropharynx, and laryingopharynx is (also called the hypopharynx).

14. Where is the nasopharynx located? And what is found in the nasopharynx?

Anterior to C-1. The eustachian tubes and adenoids are found in the nasopharynx.

15. Where is the oropharynx located?

The oropharynx is located at C-2 to C-3 and is bound superiorly by the soft palate and inferiorly by the epiglottis.

16. Where is the laryingopharynx located?

C-4 to C-6 bound superiorly by the epiglottis and inferiorly by the cricoid cartilage.

17. Where does the cricoid cartilage set in an adult and what is different in children?

C-5 and C6 Level in an adult. in children the larynx is higher in the neck and therefore the cricoid cartilage is higher.

18. What acts as a barrier to regurgitation in the conscious patient? And where is it located?

19. Describe the structures of larynx. In very general terms.

The larynx begins at the epiglottis and extends to the cricoid cartilage. It has six cartilage structures (three of which are paired).

20. Name of the three unpaired cartilages of the larynx and describe them.

21. What are the three paired cartilages of the larynx?

The arytenoid, cuneiform, and corniculate cartilages. The arytenoid's are shaped like pyramids, and because they are a point of attachment for the vocal cords, allow the opening and closing movement of the vocal cords necessary for respiration and voice. The cuneiform and corniculate cartilages are very small, and have no clear-cut function.

(See slides 22, 23 24 and 25 for illustrations)

22. What is the space between the base of the tongue in the epiglottis called?

Superior vallecula. By applying an upward force (anterior displacement) on the vallecula, the epiglottis can be moved away from glottic opening. The epiglottis is a delicate tissue and can easily be damaged producing edema, bleeding and airway obstruction.

35. What is laryngospasm?

Occurs when there is stimulation in the supraglottic region resulting in protective closure of the glottis.

What would be the afferent branch of laryngospasm? Internal branch of the superior laryngeal nerve.

What would be the efferent branch of laryngospasm? Recurrent laryngeal nerve.

36. Describe the trachea and lower airway

the trachea originates at the inferior border of the cricoid cartilage and extends to the carina (the point where it splits into the left and right bronchus.) The trachea is 10 to 20 cm long in adults. The cricoid cartilage is the only cartilage of the trachea that is a complete ring. The trachea has 16 to 20 C. shaped cartilage rings. C. shaped rings are nonexistent on the posterior trachea. Here, the trachea is divided from the esophagus by a membrane. This allows for some give with swallowing of large foodstuff. The cartilage "rings" continue until the bronchial tree divides to .6 mm in size. Here, the cartilage disappears. This is where the bronchioles begin. Bronchi provide humidification and warning of air. The right and left bronchi bifurcate at the carina. The angle of bifurcation of the right bronchus is 25 to 30°. The right upper lobe bronchus has a takeoff point just 2.5 cm from the Carina. The angle the left main stem is more acute being 45°. The left main stem travels 5 cm before it bifurcates into the upper lobe bronchus.

37. Why is the right main bronchus more susceptible to aspiration and intubation?

Anatomically, the right main bronchus has a less acute angle of 25 to 30° versus the left main bronchus which has an angle of 45°.

38. What is the most common aspiration pattern?

Right upper lobe

39. When should you perform in airway assessment and what would you want to know?

All contribute to potential airway difficulty. A complete airway exam history should be conducted in the pre-operative area. An airway assessment should be conducted whenever possible.

40. What are the five predictors of difficult bag and mask ventilation and oxygenation?

Summarized by the mnemonic obese:

the obese (body mass index greater than 26 kg/m2)

the bearded

the elderly (older than 55 years old)

the snorers

the edentulous

41. Describe assessment of oral pharyngeal space and describe components of a difficult airway.

relationship of the maxillary and mandibular incisors during normal jaw closure (prominent overbite is bad),

relationship of the maxillary and mandibular incisors during voluntary protrusion of the mandible (patient cannot bring mandibular incisors anterior to the maxillary incisors = bad),

interincisor distance (less than 3 cm is bad)

visibility of the uvula (not visible when the tongue is protruded with the patient in a sitting position = bad (Mallampati greater than 2)

shape of the palate (highly arched or very narrow = bad)

compliance of the mandibular space (stiff, indurated, occupied by a mass, or none resilient = bad)

thyromental distance (less than three fingerbreadths = bad)

length of neck (short = bad)

range of motion of the head and neck (unable to touch the tip of the chin to the chest or cannot extend the neck = bad)

42. What is the 3 -- 3 -- 2 rule?

• 3 fingers between the patient's teeth (patient's mouth should be opened adequately to allow for the placement of three fingers between the upper and lower teeth)
• 3 fingers between the tip of the jaw and the beginning of the neck (under the chin)
• 2 fingers between the thyroid notch and the floor of the mandible (top of the neck)

43. What is the thyromental distance?

This is the measurement taken from the thyroid notch to the tip of the jaw with the head extended. The normal distance is 6.5 cm or greater (4 finger widths) and is dependent on the number of anatomical factors including the position of the larynx. If the distance is greater than 6.5 cm, conventional intubation is usually possible. It is less than 6 cm intubation may be impossible.

44. What is the purpose of the Mallampati score and how is it determined?

The purpose is to correlate the oral pharyngeal space structures with the ease of direct laryngoscopy and tracheal intubation.

1. The observer is at eye level

2. Patient in sitting position

3. Patient's head is in the neutral position

4. Opens mouth maximally

5. Protrudes the tongue without phonating

45. Describe Mallampati class I

visualization of the soft palate, fauces, uvula and tonsillar pillars.

46. Describe Mallampati class II

Soft palate, fauces and uvula are visible (tonsillar pillars are missing)

46. Describe Mallampati class III

the soft palate, base of the uvula are visible

47. Describe Mallampati class IV

The soft palate is not visible only the hard palate is visible

class III and IV are classified as difficult

Describe the Flows for the Simple Mask:

What is the minimal O2 flow rate?

Max?

What percentages can I get with different flows?

5-6 L/m= 40%

6-7 l/m = 50%

7-8 L/m = 60%

Flows of at least 5 L/m needed to prevent CO2 accumulation.  Flows > 8 do not improve oxygenation above 60%

What are the 3 axis of the airway?

Which axis are lined up with the sniffing position?

1. Pharyngeal Axis

2. laryngeal Axis

3. Oral Axis

With the sniffing position the Pharyngeal-laryngeal Axis are lined up.

When should oral airways not be used?

When should nasal airways not be used?

Oral:  Pt needs to be anesthetized or airway must be anesthetized.  Inserting an oral airway under light anesthesia can cause laryngospasm.

Nasal:  Anitcoagulated pts, children with prominent adenoids, suspected skull fx.

***Note: advanced at an angle perpindicular to face in unobstructed nostril.****

Macintosh #3

Men who are taller or have longer neck anatomy or larger jaws will require the Mac 4. 

It is always better to have a blade that is a little too long vs. too short.

1. Less Dental Trauma

2. More Room for ETT

3. Less bruising of epiglottis

4. Less Stimulating

What are the common sizes and placement at the lip for ETT in men and women?

What size tube is needed for Bronchoscopy?

Women= 21 cm at the lip.  Average tube size is 7.0

Men= 23 at the lip.  Average tube size is 8.0

7.5 ETT is needed for Bronchoscopy.

The ideal pressure in an ETT tube is:______ to ______

and should never exceed: _______.

What it the proper amt. of air inflation in the balloon of an ETT?

20-30 mmHg

Never exceed 30 mmHg

The proper amt. is "to seal" generally 3-6 cc of air not to exceed 8 cc of air.

Prolonged periods of time with Nitrous can cause an increase in pressure in the balloon because nitrous can diffuse into the balloon.

****Always check pressure in prolonged cases*****

Describe Cormack & Lehane grading

Grade 1

Grade II

Grade III

Grade IV

When the larynx is visualized:

I: Visualization of entire laryngeal aperature (95%)

II: Visualization of post. part of the laryngeal aperature (4%)

III: Visualization of epiglottis only (1%)

IV: not even the epiglottis is visible (0.05%)

-Follows commands

-Clear Oropharynx/ Hypopharynx

-Intact Gag Reflex

- Sustained Head Lift > 5 seconds

- Sustained hand grasp

- Adequate pain control

- Minimal expired concentration of inhaled anesthetics.

- Vital Capacity > 10 ml/ kg

- Peak negative inspiratory pressure >20cmH2O

- Tidal Volume > 6 ml/kg

-Sustained tetanic contraction 5 seconds

- T1/T4 ratio of >0.7

-Alveolar - Arterial PaO2 gradient (on 100%) of < 350 mmHg

1. Pharyngeal pathology

2. Full Stomachs

3. Aspiration risk pathology

4. Airway pathology requiring higher ventilation pressures.

***** Ventilation through the LMA should require < 25 cm H2O pressure.******

The upper esophageal sphincter opens at pressures around 20 cm H2O Therefore use 20 cm H2O as cuttoff point.

Describe Fasting Guidlines for the following:

1) Clear liq.

2) Breast Milk

3) Infant Formula

4) Non- Human Milk

5) Light Meal

6) Fatty or large meal

1) 2 hours

2) 4 hours

3) 6 hours

4) 6 Hours

5) 6 hours

6) 8 Hours

Discuss the fluid distribution in the following (TBW):

Male

Female

Obese

Elderly

Infants

Male: 60%

Female: 55%

Obese: "Less water in obese"

Elderly: 46-52%

Infants: 70- 80 %

2/3 intracellularly

1/3 Extracellularly

3/4 interstitial

1/4 intravascular

1. Hourly Rate

2. Replacement of NPO deficit

3. Maintenance replacement

4. Surgical Loss replacement

5. Insensible and sensible loss replacement

Use the 4-2-1 rule:

4 ml/kg/hr for first 1-10 kg

2 ml/kg/hr for next 11-20 kg

1 ml/kg/hr for > 21 kg

****Shortcut is pt. weight +40*****

Hourly rate x number of NPO hours.

Divide over hours of surgery.

Replace according to pt's condition (ie: how fast you give it.)

How do you calculate Maintenance fluid for the following:

1) Minimal tissue Trauma (hand surgery,small hernia repair, simple ent?)

2) Moderate tissue trauma (open chole,uncomplicated abd. hysterectomy)

3) severe tissue trauma/ exposure (open laparotomy, bowel surgery)

4) Severe tissue trauma + (open chest and abdomen)

1) 2-4 ml/kg/hr

2) 4-6 ml/kg/hr

3) 6-8 ml/kg/hr

4) 8+ ml/kg/hr

Insensible loss does not contain solutes

Sensible loss contains solutes.

700 ml/day

300 via skin

400 via respiratory tract

Adjusting from basline: What are the other factors for insensible loss in the neonate?

How would you adjust for:

1) Prematurity?

2) Tachypnea/ RDS

3) phototherapy

4) Radiant warmer

5) increased temp.

6)Major Skin defect (ie: gastroschisis)

7) increased ambient humidity

8) saran wrap/ inner shield

1) inversely proportional to GA

2) +20 ml/kg/day

3)+ 20 ml/kg/day

4) +20 ml/kg/day

5) +40-80 ml/kg/day

6) +120 ml/kg/day

7) -12ml/kg/day

8) -4-12 ml/kg/day

**************Note all are approx. and are largely dependent upon Gestational Ages.************

- Most practitioners do not account for this loss in their hourly totals in an adult pt.

-Should be considered in the neonatal and infant pt. (refer to chart)

- Sensible loss should be accounted for if pt. is febrile.

(100-150 ml per degree > 37 celsius)

Calculation of Total Blood Volume:

1) Premature neonate

2) Infant

3) Child

4) Adult male

5) Adult female

6) Obese adults

1) 90 ml/kg

2) 85 ml/kg

3) 80 ml/kg

4) 75 ml/kg

5) 65 ml/kg

6) 55 ml/kg

Estimated Blood loss x 20%

Can be used to ballpark allowable blood loss in healthy pts.

1) Determine pt's blood volume

2) Determine Healthy HCT

3) Determine Trigger HCT

4) Multiply each above by blood volume

5) subtract healthy HCT volume from Trigger HCT

6) Multiply this number x 2 to get transfustion trigger point.

For most healthy adults Hgb of 7-8 g/dl or HCT of 21-24%

For elderly the target is set at: 10 g/dl hgb (remember hgb to hct is 1:3 approx)

             Normal     (x)       Acceptable

Premature:   40-45      45          35

Newborn:     45-65      54          30-35

3 months:    30-42      36           25

1 year:         34-42      38         20-25

6 years:        35-43      38         20-25