Respiratory 2 Flashcards
PaCO2 greater than 45
respiratory acidosis
Hypoventilation (can be due to medications that depress the resp. center)
Pulmonary disease (COPD, pneumonia, pulmonary edema) CNS disturbances that damage the respiratory center in the medulla
PaCO2 less than 35
respiratory alkalosis
Hyperventilation (can be due to anxiety)
Hyperthyroidism
HCO3 less than 22
metabolic acidosis
DM, sepsis, starvation, anaerobic metabolism, chronic diarrhea
HCO3 more than 26
metabolic alkalosis
Vomiting, gastric suction, hypokalemia, antacid abuse
Indications for Mechanical Ventilation
Apnea: post cardiac arrest, alcohol intoxication, medications
Acute Respiratory Failure
Impending Respiratory Failure
Anesthesia-induced hypoventilation
Severe Oxygenation Deficit
Non respiratory indications for mechanical ventilation
Treatment for other disease processes may cause respiratory depression:
- Chemically-induced coma for raised ICP
or cerebral edema. - Surgical healing may require patient to be very still—major abdominal surgery, skin flaps. Patient may be sedated and chemically paralyzed with cisatracurium (Nimbex), others…Atracurium or Vecuronium, for
1-2 days to allow healing of delicate anastomoses.
Risk of airway occlusion from edema—major oral surgery—need for nasal intubation until edema resolves.
Management of severe aggression—trauma resus.
Patients often drug-impaired. May require immediate sedation and intubation to facilitate treatment.
Clinical Objectives
To reverse hypoxemia
To reverse acute respiratory failure
To relieve respiratory distress
To permit sedation and /or neuromuscular block
To decrease systemic or myocardial O2 consumption (decreases work of breathing)
To maintain or improve cardiac output
To reduce intracranial pressure (keep PCo2 around 35 mmHg)
To stabilize the chest (post-cardiac surgery, or traumatic injury)
Ventilator Settings Three Important Settings
- Tidal Volume which is the amount of air pumped into the lungs with each stroke. If we breathe normally, tidal volume is what we normally inhale (approx 5-10mls/kg)
- FiO2 is the percentage of air that is oxygen that the ventilator delivers. Atmospheric air is 21% O2. A ventilator can change the percentage to a more concentrated dose (ie. 50% or 100%)
- Respiratory Rate (RR) is the rate of breaths set by the RT 10-14 range
Types of Mechanical Ventilators
Volume Cycled - Delivers a pre-determined MINUTE VOLUME as ordered by the MD/NP (Minute volume = breaths x tidal volume) This is the most common ventilator we utilize in the acute care setting.
Pressure Cycled or Pressure Control Ventilation- Delivers a set pressure (mostly used with children and infants but now commonly used for adults with decreased lung compliance-ARDS).
External Body Ventilators (Iron Lung) - Assist in spontaneous ventilatory effort by applying negative pressure to the trunk of the body (VERY rarely used today but still available)
Controlled Mandatory Ventilation
The ventilator does ALL the work. The patient is unable to take a spontaneous breath. Useful if the patient is apneic due to chemical paralysis. Allows patient to rest.
Assist Control Mode
Most patients are placed on this mode initially. It means that the machine gives the patient the number of breaths ordered (i.e., AC 12 per minute) at the tidal volume that is ordered and set on the machine (ie 450 ml TV). The ventilator will deliver 12 breaths , each breath 450 ml.
In between those 12 machine breaths, the patient can initiate extra breaths. If he patient inhales just the tiniest bit, the machine will deliver a full (ie. 450 ml) breath at the preset volume.
****Note In the AC mode, the machine does all the work. If the patient wants more air, the machine will give it with no extra work except attempting to take a breath.
SIMV Mode
Synchronized Intermittent Mandatory Ventilation (SIMV)
When a patient is starting to initiate their own breaths, the MD may wish to start “weaning” the patient from the ventilator. To start the weaning process, we encourage the client to “breathe more frequently on their own” while still having the support of the ventilator if they fail.
***Increased PEEP causes a drop in blood pressure
Pressure Support Ventilation
Often used with SIMV and CPAP
Augments a spontaneously generated breath since it adds pressure to the air the patient is inhaling.
The patient’s inspiratory effort is assisted by the ventilator at a preset inspiratory pressure (not volume).
Helps overcome “dead space.” Tubing leading to ventilator plays no part in gas exchange but patient has to expend more energy when breathing because of length of tubing. Pressure support “blows air” at the patient and makes it easier to take a breath in.
Pressure Control (PC)
Used for ARDS to avoid barotrauma and deliver smaller volumes of Vt or used for inverse I:E
PEEP
PEEP (Positive End Expiratory Pressure) is a constant small pressure that keeps the alveoli slightly inflated. PEEP prevents the alveoli from collapsing at the end of the breathing cycle. By keeping the alveoli inflated, oxygen pressure is maintained and oxygenation of the blood improved.
The pressure gauge on the ventilator will tell you if the PEEP is set since the pressure in between breaths does not return to “0”(atmospheric pressure) but is set (ie. at 5,10 or 15 cm.)
CPAP
Continuous Positive Airway Pressure, or Pressure Support Ventilation
*****Patient MUST be breathing SPONTANEOUSLY!
Continuous pressure with or without O2 is delivered to the patient in order to assist respiration, prevent/reverse alveolar collapse
**Can be used as a mode of ventilation when an intubated patient is breathing spontaneously and is being weaned. NO SET RATE. Be off sedation/very minimal to breathe
Can also be used with a tight-fitting face mask in an effort to prevent intubation in a patient with respiratory compromise. This can be VERY uncomfortable and difficult for the patient to tolerate.
CPAP Continued
Full face CPAP mask very tight—patient may not tolerate. Precedex drip often used—mild sedation without respiratory depression.
Need Q2h mouthcare and eyecare.
Nasal CPAP used for patients with sleep apnea—usually obese but not always.
If the ventilator is alarming and you don’t know why….
Ambubag with 100% O2 and call for HELP!
Ventilator Alarms Causes
Causes (most common):
Patient is biting on the ETT (insert bite block if necessary)
Patient is agitated and fighting the ventilator
Patient is coughing
Secretions or mucus in the airway
Water in the tubing or tubing kinked
Pneumothorax
Pulmonary compliance issues (developing ARDS)
Stiffening of the lungs R/T scarring or ischemia
Air trapping and reduced alveolar space-alveolar collapse.
Ventilator Alarms (Low Pressure) Causes
Causes:
Patient is disconnected, Circuit leaks, Airway leaks (ET tube dislodged or balloon deflated), Chest tube leaks
High Inspiratory Rate
The patient is breathing quite rapidly. Pain or agitation might be a reason. If the patient was breathing rapidly on SIMV, it might mean they need to be changed to Assist Control. That way they would expend less energy.
Low Minute Volume Alarm
Low Minute Volume Alarm - means the ventilator could not deliver the preset volume.
Check for tubing disconnection—most common cause.
Nursing Management Vent Alarms
Suction ETT prn. Auscultate breath sounds. Pre-oxygenate with 100% FiO2. All vents have a button that will allow you to place pt on 100% for 1-3 minutes. Suction for NO MORE than 15 seconds. Apply suction upon withdrawel of catheter.
Use closed suction system, such as Ballard.
Do not use saline lavage routinely!
*** “Routine” suctioning is not good practice-can cause traumatic injury to lungs and distress to the patient.
VAP Protocol
Keep HOB up 30 degrees if not contraindicated.
Reposition every 2 hours (aids pulmonary drainage of secretions)
Mouth care AT LEAST every 4 hours, preferably every 2 hours. Bacteria migrate downwards from the oropharynx.
Wrist restraints per hospital policy—LEAST restrictive measures always—BIG with JCAHO!
Alarms on (ventilator and monitor), appropriate parameters set, and AUDIBLE!
Ambubag at bedside and easily accessible. Keep it attached to the O2 so you can turn it on quickly in an emergency.
