Apex - Respiratory Monitors & Equipment

List 2 methods of CO2 analysis

1 mainstream (in-line) 2. sidestream (diverting)

Barotrauma risk increases when plateau pressure exceeds:

35 cmH2O

Which will affect reliability of the pulse oximeter? - Polycythemia - hgb F - CPB - vasoconstriction - indigo carmine - indocyanine green - fluorescein - methylene blue - jaundice - acrylic fingernails - shivering - raynaud's disease

Affects reliability - CPB - vasoconstriction - indigo carmine - indocyanine green - methylene blue - raynaud's disease Does not affect reliability - Polycythemia - hgb F - fluorescein - jaundice - acrylic fingernails

How does the location of the pulse oximeter affect response time?

As a general rule, the closer the monitoring site is to the central circulation, the faster it will respond to arterial desaturation - Fast = ear, nose, tongue, esophagus, forehead - middle = finger - slow = toe

Which conditions are MOST likely associated with an airway pressure waveform with an elevated peak pressure with a normal plateau pressure? (Select 3) A. Pneumothorax B. Bronchospasm C. Aspiration of foreign body D. Endobronchial intubation E. Pulmonary edema F. Kinked endotracheal tube

B. Bronchospasm C. Aspiration of forein body F. Kinked endotracheal tube Pattern suggests a reduction in dynamic compliance, which is usually caused by increased airway resistance.

What type of pulmonary compliance is a function of both airway resistance and elasticity of the chest wall?

Dynamic compliance

What is the formula for dynamic compliance?

Dynamic compliance = Vt / (PIP - PEEP)

Which will cause increased EtCO2? - opioid OD - hypothermia - decreased CO - airway obstruction - thyrotoxicosis - tourniquet removal - increased apparatus dead space - V/Q mismatch - Laparoscopy - PE - Hypotension - MH - esophageal intubation - incompetent unidirectional valve

Increased EtCO2 - opioid OD - thyrotoxicosis - tourniquet removal - increased apparatus dead space - Laparoscopy - PE - MH - incompetent unidirectional valve Decreased EtCO2 - hypothermia - decreased CO - airway obstruction - V/Q mismatch - Hypotension - esophageal intubation

Where there is an increase in total lung compliance, what are the expected changes in PIP & Plateau pressure?

Increased PIP & increased PP Examples: - endobronchial intubation - pulmonary edema - pleural effusion - tension pneumothorax - atelectasis - chest wall edema - abdominal insufflation - Ascites - trendelenburg position - inadequate muscle relaxation

When there is an increase in airway resistance, what are the expected changes in PIP & Plateau pressure?

Increased PIP with no change in PP Examples - kinked endotracheal tube - endotracheal tube cuff herniation - bronchospasm - bronchial secretions - compression of the airway - foreign body aspiration

Which will increase pulmonary resistance? - Inadequate muscle relaxation - Tension pneumothorax - Trendelenburg - Foreign body aspiration - Pleural effusion - Kinked ETT - Pulmonary edema - Endobronchial intubation - Abdominal insufflation - Bronchospasm - Atelectasis - Airway compression - Ascites - Bronchial secretions - ETT cuff herniation

Increases pulmonary resistance - Foreign body aspiration - Kinked ETT - Bronchospasm - Airway compression - Ascites - Bronchial secretions - ETT cuff herniation Decreases pulmonary compliance - Inadequate muscle relaxation - Tension pneumothorax - Trendelenburg - Pleural effusion - Pulmonary edema - Endobronchial intubation - Abdominal insufflation - Atelectasis

Which will shift the oxyhemoglobin dissociation curve to the left? - Pyrexia - Hypoxia - Malignant hyperthermia - hgb F - decreased 2,3-DPG - chronic anemia - hgb CO - increased 2,3-DPG - Hypercapnia - Thyroid storm - Hypothermia - hgb Meth - decreased pH - hypocapnia - increased pH

Shift left - hgb F - decreased 2,3-DPG - hgb CO - Hypothermia - hgb Meth - decreased pH - hypocapnia - increased pH Shift right - Pyrexia - Hypoxia - Malignant hyperthermia - chronic anemia - increased 2,3-DPG - Hypercapnia - Thyroid storm

Which method of CO2 analysis will take longer to reveal a circuit disconnect?

Sidestream (diverting)

What is an acceptable margin of error for the pulse oximeter?

SpO2 70-100% = +/- 2-3% SpO2 50-70% = 3%

The mixed venous O2 saturation monitor reads 70%. Estimate the PvO2.

SpO2 90% = PO2 60 mmHg SpO2 80% = PO2 50 mmHg SpO2 70% = PO2 40 mmHg

The pulse oximeter reads 80%. You estimate the PaO2 is approximately?

SpO2 90% = PaO2 60 mmHg SpO2 80% = PaO2 50 mmHg SpO2 70% = PaO2 40 mmHg

What type of pulmonary compliance is a function of the elasticity of the chest wall only?

Static compliance

What is the formula for static compliance?

Static compliance = Vt/(plateau pressure - PEEP)

In which patients is the pulse oximeter MOST likely to provide an inaccurate measurement? (select 2) a. 3yo toxic from EMLA cream OD b. 7yo rescued from a basement fire c. 10yo with jaundice d. 15yo who received fluorescein

a. 3yo toxic from EMLA cream OD b. 7yo rescued from a basement fire

Which conditions are associated with a decreased PaCO2 to EtCO2 gradient? a. dysfunctional inspiratory unidirectional valve b. seizures c. CO2 absorption during laparoscopic surgery d. venous air embolism

a. dysfunctional inspiratory unidirectional valve

Which condition is LEAST likely to affect the reliability of the pulse oximeter? a. jaundice b. left ventricular assist device c. carboxyhgb d. blue nail polish

a. jaundice

During a lap gastric sleeve procedure, the peak inspiratory pressure acutely increases from 38 to 52 cm H2O. The plateau pressure remains unchanged. What are the MOST likely etiologies of these findings? (select 2) a. kinked ETT b. tension pneumothorax c. pulmonary edema d. bronchospasm

a. kinked ETT d. bronchospasm increased PIP w/ unchanged PP = increased airway resistance

Which conditions are MOST likely to cause a reduced EtCO2 waveform? (Select 2) a. metabolic acidosis b. pulmonary embolism c. metabolic alkalosis d. inadequate seal with LMA e. sodium bicarbonate administration f. seizure

a. metabolic acidosis (hyperventilation from increased MV) b. pulmonary embolism d. inadequate seal with LMA

Select the statements that MOST accurately describe pulse oximetry. (Select 2) a. oxygenated hgb absorbs light at 940 nm b. at the peak of the waveform, the ratio of arterial blood to venous blood is reduced c. it is based on the beer-lambert law d. it is based on the doppler effect

a. oxygenated hgb absorbs light at 940 nm - oxygenated absorbs near-infrared light (940nm) - deoxygenated absorbs red light (660nm) c. it is based on the beer-lambert law

Infrared analysis is able to measure: (Select 3) a. xenon b. CO2 c. volatile anesthetics d. oxygen e. N2O f. helium

b. CO2 c. volatile anesthetics e. N2O

Which condition can cause a falsely increased pulse oximeter value? a. tricuspid regurgitation b. carboxyhgb c. flourescein d. red nail polis

b. carboxyhgb

What is the MOST reliable monitor for the detection of bronchial intubation? a. oxygen analyzer b. chest auscultation c. capnograph d. pulse oximeter

b. chest auscultation

Which pulse oximeter location is associated with the slowest response time? a. tongue b. finger c. ear d. nose

b. finger

Placing the pulse oximeter on which finger is MOST likely to cause a corneal abrasion during anesthetic emergence? a. ring b. index c. middle d. pinky

b. index

Determinants of dynamic compliance include all of the following EXCEPT: a. Vt b. plateau pressure c. PIP d. PEEP

b. plateau pressure

Which of the following is the LEAST reliable monitor of endobronchial intubation? a. pressure-volume loop b. pulse oximeter c. fiberoptic bronchoscope d. lung auscultation

b. pulse oximeter

Choose the statement that reflects the MOST complete understanding of pulse oximetry. a. at the trough of the waveform, the sample contains more arterial blood b. it emits two wavelengths of UV light c. 660 nm light is preferentially absorbed by reduced Hgb d. it is based on the coanda effect

c. 660 nm light is preferentially absorbed by reduced Hgb

What is the MOST likely cause of an acute reduction in the EtCO2 concentration? a. convulsions b. rebreathing c. hemorrhage d. opioid OD

c. hemorrhage

When compared to a mainstream CO2 sensor, which of the following is an advantage of a sidestream CO2 sensor? a. absence of a pumping mechanism b. elimination of the water trap c. less apparatus dead space d. faster response time

c. less apparatus dead space

What is the Most common method of measuring exhaled gases inside the breathing circuit? a. mass spectrometry b. raman scattering c. piezoelectric crystals d. infrared absorption

d. infrared absorption

Which monitor is unable to measure the oxygen concentration in the breathing circuit? a. clark electrode b. paramagnetic analysis c. raman scatter spectrometry d. infrared absorption spectrophotometry

d. infrared absorption spectrophotometry

All of the following contribute to an increased PaCO2-EtCO2 gradient EXCEPT: a. PE b. sample line leak c. right-to-left shunt d. laparoscopy

d. laparoscopy

During anesthetic induction, the SpO2 fails to display on the monitor. The circulating nurse notes that the patient is wearing green nail polish. What is the MOST appropriate intervention at this time? a. monitor serial ABGs during the procedure b. switch to a cerebral oximeter c. remove the fingernail polish d. rotate the probe 90 degrees on the finger

d. rotate the probe 90 degrees on the finger

Which of the following is a contraindication to pulse oximetry? a. CPR b. Raynaud's disease c. takayasu arteritis d. there are no contraindications to pulse oximetry

d. there are no contraindications to pulse oximetry

The pulse oximeter is a useful monitor of: a. ventilation b. bronchial intubation c. anemia d. vascular compression

d. vascular compression

Describe the optical characteristics of methemoglobin

equally absorbs near red light (660nm) & near-infrared light (940 nm) - overestimates <85% - underestimates >85%

What wavelength of light is preferentially absorbed in venous blood?

red light = 660 nm