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Flashcards in mechanical ventilation Deck (30)
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1
Q

what is mechanical ventilation?

A
  • a machine that generates a controlled flow of gas into a pts airway
  • O2 and air are generated from cylinders or wall outlets
  • the gas is blended according to prescribed “inspried oxygen tension”- FiO2
  • its accumulated in a receptacle in the machine, then delivered to pt via one of many available modes
2
Q

indications for ventilation

A

-ventilatory failure
-inability to protect airway
-failure to clear the airway
(ARB, allergic reactions, etc.)

3
Q

airway accesses

A

-Noninvasive ventilation
-nasal cannula, face mask, non-rebreather mask,
BiPAP
-Laryngeal Mack airway (LMA)
-endotrachial tube
-tracheostomy (for prolonged intubation)

4
Q

types of ventilators

A
  • negative pressure ventilators
  • positive pressure ventilators
  • non-invasive ventilation
5
Q

negative- pressure ventilation

A

-creates negative pressure externally to draw the chest outward and air into the lungs
-mimics spontaneous breathing
-used for individuals with neuromuscular disorders
“iron lung”

6
Q

Positive pressure ventilation

A
  • Pushes air into lungs
  • can be invasive or non-invasive
  • amount of air delivered in: volume (milliliters), specific pressure
  • used for individuals with acute respiratory failure
7
Q

BIPAP

A

noninvasive positive pressure ventilator

  • provides ventilator support, but uses a tight fitting mask
  • used to avoid intubation
  • supportive for patients with: sleep apnea, impending respiratory failure
  • success varies and is limited to pt tolerance
8
Q

Positive pressure ventilators

A
  • normal respiratory properties will be reflected in your mechanical ventilation settings
  • mode (spontaneous vs. mechanical)
  • depth (tidal volume)
  • oxygen (FiO2)
  • rate
9
Q

controlled mechanical ventilation (CMV)

A
  • mode of positive-pressure ventilation
  • breaths are delivered regulatory and independent of the pts own ventilatory efforts
  • used when pt has no drive to breathe (-under anesthesia, chemically paralyzed)
  • very rarely used
10
Q

assist-controlled mechanical ventilation (ACV)

A

-mode of positive-pressure ventilation
-vent breath is triggered by pt inspiration
-used: to initiate mechanical ventilation
those at risk for respiratory arrest
-if the pt does not initiate a breath in a preset time the vent fires a breath at the preset vent rate
allows pt to breath faster but not slower

11
Q

synchronous intermittent mandatory ventilation (SIMV)

A

mode of positive pressure ventilation

  • allows pt to breath spontaneously without vent assistance between delivered vent breaths
  • -vent has preset rate and tidal volume and will not fire when the pt produces their own breath
  • coordinated with the pts own respiratory effort
12
Q

SIMV commonly used

A
  • to support ventilation
  • to exercise the respiratory muscles between vent-assisted breaths
  • during weaning process
13
Q

Respiratory rate - SIMV rate =

A

spontaneous breaths

14
Q

Tidal volume (VT)

A
  • the volume of air delivered during each ventilator-augmented breath
  • normal adult VT is 6-10 mL/kg or approx. 400-500mL
  • increased VT = increased risk of barotrauma & decreased venous return/ CO
  • decreased VT = increased risk of atelectasis
15
Q

Oxygen

A
  • 3% of the body’s oxygen is dissolved in the plasma
  • PaO2=partial pressure of oxygen (mmHg)
    • measures how much oxygen is in the alveoli
  • SaO2 (oxygen saturation) measures the degree of oxygen bound to hemoglobin
16
Q

FiO2

A
  • set at lowest possbile level for adequate tissue perfusion
  • FiO2 can be 21-100% oxygen
  • try to keep
17
Q

hypoxemia

A
  • abnormally low concentration of oxygen in blood
  • results from ventilation or circulatory problems
  • VQ mismatching (shunting)
18
Q

rate of ventilations

A
  • normal RR= 12-20

- initially set at approx. 12-15 vent breaths/min

19
Q

Positive end-expiratory pressure (PEEP)

A

special ventiltor setting

  • used to maintain postive pressure in the lungs at the end of expiration
  • improves the VQ relationship and diffusion across the alveolar- capillary membrane
  • prevents: atelectasis, reduces hypoxemia, allows for lower % of FiO2
20
Q

pressure support ventilation (PSV)

A
  • preset pressure delivery augmenting pt own respiratory effort
  • applies positive pressure during “spontaneous” inspiration
  • can be used with all modes of ventilation
  • used to: over come dead space of circuit & pts airways, decreases the work of breathing
  • pt must be doing some spontaneous breathing
21
Q

continuous positive airway pressure (CPAP)

A
  • special ventilator setting
  • elevates end-expiratory pressure during spontaneous breaths
  • used for intubated and non-intubated pts
  • used ot: maintain open airways, decrease the work of breathing
22
Q

CPAP mask or BiPAP?

A

-used to improve oxygenation on pts who can breath on their own
-used for those experiencing sleep apnea at night
masks must be tight on the face

23
Q

complications of mechanical ventilation-improper tube placement

A
  • inflated lung vs. uninflated lung
  • gastric distention
  • aspiration
  • facial skin necrosis
  • crepitus
  • drying of eyes and mucous membranes
  • stress
  • claustrophobia
  • *need to perform oral and nasal care every 4 hrs
24
Q

complications of mechanical ventilation-hospital acquired pneumonia

A
normal respiratory defense mechanisms bypassed
-open epiglottis
-cough/gag reflexes inhibited/ impaired
-secretions often thick and tenacious 
       -increases risk of atelectasis
hand washing vital in prevention
25
Q

other complications of mechanical ventilation

A
  • aspiration
  • oxygen toxicity
  • resp. acidosis/alkalosis
  • failure to wean
  • decreased BP & CO
  • poss. liver and renal dysfunction
  • increased ICP
  • fistulas
  • barotrauma
  • fluid retention
  • loss of muscular conditioning
  • malnutrition
26
Q

ventilator weaning

A
  • the process of removing ventilator support and re-establishing spontaneous, independent breathing
  • process depends on: preexisting lung condition
  • duration of mechanical ventilation
  • pts general condition-physically and psychologically
27
Q

vent. weaning cont.

A
  • SIMV and PSV are used for weaning
  • when duration of mechanical ventilation has been longer and respiratory muscle reconditioning is needed
  • duration of periods off the vent is gradually increased until pt can maintain adequate independent breathing for several hours
28
Q

using SIMV to wean

A

number of vent assisted breaths are gradually decreased

-when pt is able to tolerate an SIMV of 4 bpm a T piece or CPAP weaning is attempted

29
Q

using PSV to wean

A
  • pressure support levels are gradually decreased

- when PSV is just enough to overcome ETT resistance; support is DC’d; pt is extubated

30
Q

terminal wean

A
  • gradual withdrawal of mechanical ventilation when survival without assisted ventilation is not expected
  • nursing considerations
  • need to discuss option with pt/family/SO
  • When? Where? What?
  • provide education and comfort