Terms in this set (30)
What does IPPV stand for?
Intermittent positive pressure ventilation
During what phase(s) of respiration is positive pressure maintained in IPPV?
Squeezing an ambu bag is an example of what type of mechanical ventilation?
Intermittent positive pressure (IPPV)
What type of mechanical ventilation is used to open small airways following lung trauma, or secondary to pulmonary edema?
Positive end-expiratory pressure
What is the average tidal volume for small animal patients?
Residual lung volume can be reduced by what anesthetic drug?
What is the difference between hyperpnea, polypnea, and tachypnea?
Hyperpnea = fast, deep breathing
Polypnea = rapid, shallow panting
Tachypnea = increased rate of respiration
What is Cheyne-Stokes respiration?
An increase in rate and depth of respiration, followed by brief apnea
What is Biot's respiration?
Sequences of gasps, apnea, and several deep gasps
What is Kussmaul's respirations
Regular deep respirations without pause
What is apneustic respiration?
The holding of an inspired breath for short periods.
What clinical and physiological parameters determine whether a patient should be ventilated?
Clinical -- patient not breathing adequately on own or is difficult to keep anesthetized
Physiological -- abnormal blood gas values
True or false: all anesthetized patients hypoventilate.
What are some pre-surgical indications for mechanical ventilations?
- Use of neuromuscular blocking drugs
- Intrathoracic surgery
- Surgeries longer than 90 minutes
- Significant metabolic disease
What is the major "goal" of mechanical ventilation?
To maintain the PaCO2 in the normal range (between 35-45 mmHg)
During spontaneous ventilation, what parts of the lungs undergo the greatest volume changes? What changes about this during mechanical ventilation?
In spontaneous ventilation, the peripheral fields (where the most gas exchange occurs) undergo the greatest volume change. With mechanical ventilation, the peribronchial and mediastinal areas of the lung (where the least gas exchange occurs) undergo the greatest volume change.
How does positive pressure ventilation affect lung compliance?
How does positive pressure ventilation affect cardiac output?
How does positive pressure ventilation affect ventilation-perfusion mismatching?
What can you do to minimize the increase in intrathoracic pressure during assisted ventilation?
Deliver the breath over a short period of time (~1 second).
What are the ideal inspiration-expiration ratios for small and large animals, respectively?
Small animals: 1:2
Large animals: 1:1
(both can go as high as 1:4.5)
Name three potentially harmful effects of IPPV?
- Lung injury
- Ventilation-perfusion mismatch
- Over/under ventilation leading to hypo or hypercapnea
What are the two sources of gas in a "double circuit" ventilator?
- The driving gas (outside the bellows) which compresses the bellows
- The patient gas (inside of the bellows) which starts at the anesthesia machine and delivers oxygen & anesthetic
What are the 3 classifications of mechanical ventilators?
- Volume preset
- Pressure preset
- Time cycled
What are the 2 disadvantages of volume-preset ventilators?
- High pressure airways may develop
- They cannot compensate if there are any leaks in the system
Which type of mechanical ventilator has the highest "safety factor"?
Which type of volume-preset bellows are considered safer: ascending or descending?
Classification of ventilator bellows is based on their movement during what stage of respiration?
What are seven causes of apnea following controlled ventilation?
- Decreased PaCO2
- No external stimuli to breathe
- Short procedure done w/ injectable anesthetic
- Use of pre-anesthetic agents
- Deep anesthetic plane
- Use of neuromuscular blocking agents
What are the five steps of weaning a patient off a mechanical ventilator?
1. Decrease rate of and/or tidal volume
2. Decrease anesthetic depth
3. Reverse neuromuscular blockade
4. Antagonize opioid-induced respiratory depression
5. Physically manipulate the patient