Mechanical Ventilation

MECHANICAL VENTILATION

VENTILATORY CONCEPTSMechanical ventilation is

physiologically a supportive not a curative device. But the first step of

any mechanical ventilation. “DO NO HARM”

DEFINITIONMechanical ventilation is a positive or negative pressure

artificial breathing device that can maintain ventilation and oxygen delivery for prolonged periods. (It is indicated when the patient is unable to maintain safe levels of oxygen or CO2

by spontaneous breathing even with the assistance of other oxygen delivery devices

Nov 2006 Kishore P.Critical Care Conference

WHY VENTILATE?

• Improve oxygenation• Increase/maintain minute ventilation and

help CO2 clearance

• Decrease work of breathing• Protect airway

COMPONENTS OF AIRWAY PRESSURE DURING MECHANICAL VENTILATION

1. RESISTIVE PRESSURE2. ELASTIC PRESSURE3. END-EXPIRATORY PRESSURE

Origins of mechanical ventilationOrigins of mechanical ventilation

•Negative-pressure ventilators (“iron lungs”)

•Non-invasive ventilation first used in Boston Children’s Hospital in 1928

•Used extensively during polio outbreaks in 1940s – 1950s

•Positive-pressure ventilators

• Invasive ventilation first used at Massachusetts General Hospital in 1955

•Now the modern standard of mechanical ventilation

The era of intensive care medicine began with positive-pressure ventilation

The iron lung created negative pressure in abdomen as well as the chest, decreasing cardiac output.

Iron lung polio ward at Rancho Los Amigos Hospital in 1953.

IRON LUNG CIRCA 1950’S

MODERN(IZED) IRON LUNG

CHEST CUIRASS

Complications with Negative Pressure Ventilation

• Limited access for patient care.• Inability to properly monitor pulmonary

mechanics.• Patient discomfort.

INDICATIONSMechanical failure of Ventilation1. Neuromuscular disease2. Central nervous system disease3. CNS depression (drug intoxication, respiratory depressants, cardiac arrest)4. Musculoskeletal disease5. Inefficiency of thoracic cage in generating pressure gradient necessary for ventilation (chest injury, thoracic malformation)

Disorders of Pulmonary Gas Exchange1. Acute respiratory failure2. Chronic respiratory failure3. Hypoxemia( not responding to supplemental oxygen and fluid resuscitation)4. Acute hypercapnia ( with worsening acidosis)5. Pulmonary disease resulting in diffusion abnormality6. Pulmonary diseases resulting in ventilation-perfusion mismatch 

Others1. Thoracic and abdominal surgeries2. Inhalation injuries, multiple traumas, shock3. Multiple system failure

Indications For Mechanical Ventilation 1. PaO2 <50 mm Hg with Fio2> 0.602. PaCO2 > 50 mm Hg with pH < 7.253. Vital capacity < 2 times tidal volume4. Negative inspiratory force <25 cm H2O5. Respiratory rate >35/min

Acute Ventilatory Failure/Arrest- A sudden increase in the PaCO2 to greater than 50mmHg with an accompanying respiratory acidosis (pH<7.3)

INDICATIONS CONTD.Impending Ventilatory Failure- Occurs when a patient can maintain marginally normal blood gases, but only at the expense of significantly increased WOB.Severe Hypoxemia- present when a patient has a PaO2 less than 60mmHg on ≥ 50% oxygen or less than 40 mmHg on any FiO2.

UNDERLYING PRINCIPLES1. Variable that control ventilation and oxygenation include:A. Ventilator rate adjusted by rate setting.B. Tidal Volume (VT) adjusted by tidal volume setting; measured as inhaled volume.C. Fraction inspired oxygen concentration (FiO2) Set on ventilator or with an oxygen blender; measured with an oxygen analyzer.D. Ventilator dead space circuitry (tubing) common to inhalation and exhalation; tubing is calibrated.E. PEEP set within the ventilator or with the use of external PEEP devices; measured at the proximal airway.

2. CO2 elimination is controlled by VT rate, and dead space. 3. Oxygen tension is controlled by oxygen concentration and PEEP4. In most cases the duration of inspiration should not exceed inhalation.a. Rate, tidal volume, gas flow in liters per minute and inspiratory pause all control inspiratory time.B. Inverse I: E ratio result in “stacking” of breath or build up of pressure within the airway. Barotrauma and decreased cardiac output can result when inverse I: E ratio is used.5. The inspired gas must be warmed and humidified to prevent thickening of secretions and decrease in body temperature. Sterile or distilled water is warmed and humidified by way of a heated humidifier.

Classification of Ventilators

POSITIVE PRESSURE VENTILATORS

• Volume-cycled– terminate inspiration

after delivering a preset volume of gas

– delivered regardless of required pressure to do so

– volume remains the same unless high peak pressures reached

• Pressure-cycled – terminate inspiration when

a preset pressure is reached– varying degrees of

resistance will interfere with gas flow

– best used with drug overdose patients

– not good for post-operative or severe respiratory infections

Pressure ventilation vs. volume ventilationPressure ventilation vs. volume ventilation

Pressure-cycled modes deliver a fixed pressure at variable volume (neonates)Volume-cycled modes deliver a fixed volume at variable pressure (adults)

•Pressure-cycled modes•Pressure Support Ventilation

(PSV)•Pressure Control Ventilation

(PCV)•CPAP•BiPAP

•Volume-cycled modes•Control•Assist•Assist/Control• Intermittent Mandatory

Ventilation (IMV)•Synchronous Intermittent

Mandatory Ventilation (SIMV)

Volume-cycled modes have the inherent risk of volutrauma.

Negative pressure ventilatorsThey exert a negative pressure on the external chest wall. This causes decreasing the intrathoracic pressure during inspiration which allows air to flow into the lungs, filling its volume. Physiologically this type of assisted ventilation is similar to spontaneous breathing.USES 1. It is used mainly in chronic respiratory failure associated with neuromuscular conditions such as poliomyelitis, muscular dystrophy, amyotrophic lateral sclerosis and myasthenia gravis. 2. Not used for serious patients3. Simple to use4. Do not require intubation5. Adaptable for home use EXAMPLESIron lung, body wrap and chest cuirass

POSITIVE PRESSURE VENTILATORSPositive pressure ventilators inflate the lungs by exerting positive pressure on the airway, similar to bellow mechanism, forcing the alveoli to expand during inspiration. Exhalation is passive. Endotracheal intubation or tracheotomy is necessary in most cases. They are widely used in hospital settings. There are three types of positive pressure ventilators, which are classified by the method of ending the inspiratory phase of respiration:1. Pressure cycled Ventilators2. Time Cycled ventilators3. Volume Cycled Ventilators4. Non-invasive positive pressure ventilator

PRESSURE CYCLED VENTILATORSThe pressure cycled ventilators is a positive pressure ventilator that ends inspiration when a preset pressure is reached. The ventilator cycles on, deliver a flow of air until a predetermined pressure is reached and then cycles off. The major limitation of this type of ventilator is that the volume of air or oxygen can vary as the patient’s airway resistance or compliance changes. The result is an inconsistency in the tidal volume delivered and possible compromised ventilation. Pressure cycled ventilator are intended only for short-term use. The most common type is IPPB-Intermittent positive pressure breathing machine

TIME CYCLED VENTILATORSThey terminate or control inspiration after a preset time. The volume of air patient received is regulated by the length of inspiration and the flow rate of the air. Most ventilators have a rate control that determines the respiratory rate but pure time-cycling is rarely used for adults. They are used in newborns and infants.

VOLUME CYCLED VENTILATORSThey are by far the most commonly used positive pressure ventilators today. With this type of ventilator, the volume of air is delivered with each inspiration is preset. Once the preset volume is delivered to the patient the ventilator cycles off and exhalation occurs passively. From breath to breath, the volume of air delivered by ventilator is relatively constant, ensuring consistent, adequate breath despite varying airways pressures.

NONINVASIVE POSITIVE -PRESSURE VENTILATIONPositive pressure ventilation can be given via face mask that covers the nose and the mouth, nasal masks or other nasal devices. Ventilation can be delivered by volume ventilator, pressure controlled ventilator, continuous positive pressure device or bi-level positive pressure ventilator. The most comfortable mode for the patient is pressure controlled ventilation with pressure support. This eases the work of breathing and enhances the gas exchange.

Indications for NIPPV1. Acute or chronic respiratory failure2. Acute pulmonary edema3. COPD 4. Chronic congestive heart failure with a sleep rated breathing disorder5. Obstructed sleep apnea

Contraindications1. Critically ill patients2. Cognitively impaired patients Nursing consideration for these patients includes assessment for nasal mask intolerance, facial skin breakdown and eye irritation.

NON-INVASIVE VENTILATION

• Potential benefits of noninvasive positive pressure ventilation(NPPV):– Reduce intubation in patients with acute respiratory

failure– Reduce nosocomial pneumonia rates – Reduce upper airway traumatic injury

NON-INVASIVE VENTILATION

• Potential benefits of NPPV (cont):– Increase patient comfort– Allow patient to talk– Potentially reduce mortality, length of mechanical

ventilation, ICU stay, and hospital costs– Increases patient’s comfort & allow patient to talk– Potentially reduces mortality, length of mechanical

ventilation, ICU stay & hospital costs.

NPPV- PATIENT SELECTION• Appropriate diagnosis with potential reversibility

• Moderate to severe respiratory distress – use of accessory muscles, abdominal paradox

• Respiratory acidosis and hypercapnia (PaCO2 > 45 mm Hg and arterial pH < 7.35)

• Tachypnea - rate > 25 breaths/min

NPPV – PATIENT EXCLUSION• Respiratory arrest or imminent respiratory arrest• Hemodynamic instability• Inability to protect airway• Uncooperative patient, severe anxiety• Craniofacial trauma or burns• Life-threatening refractory hypoxemia (eg paO2< 60 mmHg

with 100% FiO2)

BIPAP VentilationThis offers independent control of inspiratory and expiratory pressures while providing pressure support ventilation. It is provided via a nasal or oral mask, nasal pillow, or mouthpiece with a tight seal with a portable ventilator. It is most often used for patients who require ventilator assistance at night, such as patients with severe COPD or sleep apnea.

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Rate

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FiO2

PEEP

Vt

CMV

SIMV

PCV

PSVModesModes

ControlsControls

ConventionalConventional

ACV

CPAP

VOLUME MODES CONTROLLED MODE VENTILATION (CMV) All breaths are controlled by the ventilator. This ventilatory pattern is independent of patient effort, and between ventilator breaths, the inspiratory valve is closed to the patient such that no additional breaths can be taken.Volume controlled ventilators delivered a predetermined tidal volume at a specified inspiratory flow rate and terminate inspiration when that volume has been delivered, irrespective of the developed airway pressures, which are determined by the lung mechanics.Indicated for those whose respiratory drive is absent. Not suitable for patients having their own spontaneous respiratory efforts as it can lead to dyssynchrony between patient’s and ventilator’s effort to ventilate

ASSIST/CONTROL MODEASSIST/CONTROL MODE

•CONTROL MODE•Pt receives a set number of

breaths and cannot breathe between ventilator breaths

•Similar to Pressure Control

•ASSIST MODE•Pt initiates all breaths, but

ventilator cycles in at initiation to give a preset tidal volume

•Pt controls rate but always receives a full machine breath

•ASSIST/CONTROL MODE•Assist mode unless pt’s

respiratory rate falls below preset value

•Ventilator then switches to control mode

•Rapidly breathing pts can overventilate and induce severe respiratory alkalosis and hyperinflation (auto-PEEP)

Ventilator delivers a fixed volume

Nov 2006 Kishore P.

ASSIST CONTROL (A/C)• In addition to a preset number of mandatory breaths, the

ventilator delivers additional full breaths whenever the patient has a spontaneous respiratory effort

• Sensitivity of trigger important

INTERMITTENT MANDATORY VENTILATIONAllows patient to breathe spontaneously through ventilator circuitry. Periodically at preselected rate and volume or pressure cycle to give a “mandated” ventilator breaths. A minimum level of ventilation is provided. In between the mandated breaths, the patient is free to breath at his desired respiratory rate. Indicated for patients who are breathing spontaneously, but at a tidal volume and/or rate less than adequate for their needs. Allows the patients to do some of the work of breathing.

ADVANTAGES1. Between the mandatory breaths the patient is free to choose his own respiratory rate, tidal volume and flow rate.2. The mandatory breath is delivered in synchrony with patient effort, making for comfortable breathing.3. The patients’ respiratory muscles are active and so disuse atrophy is less common.

DISADVANTAGES1. Hypoventilation is possible if the mandatory breath rate is not set high enough.2. Work of breathing may be high if trigger-sensitivity and flow rate are inappropriate to patients needs.3. Excessive work of breathing may occur during the spontaneous breaths unless an adequate level of pressure support is added

SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION(SIMV)1. Allows patient to breath spontaneously through the ventilator circuitry.2. Periodically at a preselected time, a mandatory breath is delivered. The patient may initiate the mandatory breath own inspiratory effort, and the ventilator breath will be synchronized with the patients efforts, or will be “assisted”. If the patient does not provide inspiratory effort breath will still be delivered or “controlled”

The ventilator attempts to synchronize the set number of mandatory breaths with the patients respiratory effortsThe ventilator waits for a patient effort during a sensitive peroid before every breath. In its absence, it gives a controlled breathSpontaneous breaths outside of this sensitive period are unsupportedCommonly used mode

SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION(SIMV)

Machine BreathsMachine Breaths Spontaneous Spontaneous BreathsBreaths

PRESSURE MODES

PRESSURE SUPPORT VENTILATION1. The pressure support ventilation is patient-triggered, flow cycled, pressure supported mode where each inspiratory effort of the patient is augmented by the ventilator at a preset level of inspiratory pressure. 2. During spontaneous inspiration, ventilator circuitry is rapidly pressurized to the predetermined pressure and held this pressure.3. When the inspiratory flow rate decreases to a preset minimum level (20%-25% of peak inspiratory flow), the positive pressure returns to baseline and the patient may exhale.4. The patient ventilates spontaneously, establishing own rate and inspiring the VT that feels appropriate.5. Pressure support may be used independently as a ventilator mode or used in conjunction with CPAP or SIMV.

Advantages1. Maximizing patient control of respiration, thereby enhancing patient comfort on the ventilator.2. Overcoming the work of breathing imposed by endotracheal tubes and ventilator circuitry.3. Allow adjustment of the imposed work of breathing.4. Providing alternative mode of weaning from mechanical ventilation.

Disadvantages1. PSV is not used as a sole ventilator support during acute respiratory failure because of the risk of hypoventilation.2. Not suitable for the management of patient with central apnea.3. Developed of atelactasis due to smaller tidal volume in patients with brief inspiratory times and high respiratory impedance. 4. There may be circuit leak which can cause persistent inspiratory pressure to be delivered. 

SPECIAL POSITIVE PRESSURE VENTILATION TECHNIQUES

POSITIVE END-EXPIRATORY PRESSURE

PEEP refers to the application of a fixed amount of positive pressure to a mechanical ventilation cycle during which

spontaneous breathing is not present. This pressure is also applied during inspiration so that positive pressure is

maintained in the lung throughout the breathing cycle.

PEEP is a ventilator maneuver in which the pressure is applied to the airways during exhalation. Normally during

exhalation airway pressure drops to zero and exhalation occurs passively. With PEEP exhalation remains passive but pressure falls to a preset level greater than zero often 3-20 cm of H2O.

With PEEP lung volume during expiration and between breaths is greater than normal. Thus PEEP increases FRC and

this often improves oxygenation by increased aeration of patent alveoli's, aeration of previously collapsed alveoli and prevention of alveolar collapse throughout the respiratory cycle. Peep is prescribed in terms of 2-5cm of H2O and is

titrated to the point that oxygenation improves without compromising hemodynamic. This is termed as best or

optimal PEEP.

Positive End-expiratory Pressure (PEEP)

What is PEEP?What is the goal of PEEP?

-Improve oxygenation-Diminish the work of breathing-Different potential effects-Increase the surface area of gas-exchange-preventing collapse of alveolar units.Avoiding end expiratory alveolar collapse

ADVANTAGES1. Because a greater surface area for diffusion is available and shunting is reduced, it is often possible to use a lower FiO2 than otherwise would be required to maintain adequate arterial oxygen levels. This reduces the risk of oxygen toxicity in conditions such as acute respiratory distress syndrome (ARDS).2. Positive intra-airway pressure may be helpful in reducing the transudation of fluid from the pulmonary capillaries in situation where capillary pressure is increased (i.e., left sided heart failure).3. Increased lung compliance resulting in decreased work of breathing.

DISADVANTAGES1. Increased mean airway pressure by

PEEP may result in a decrease in cardiac output.

2. The decreased venous return may cause anti diuretic hormone formation to be stimulated, resulting in decreased

urine output.

PEEP

• CONTRAINDICATION:– No absolute CI

– Barotrauma– Airway trauma– Hemodynamic instability– I.C.P.?– Bronchospasm?

CONTINOUS POSITIVE AIRWAY PRESSURECPAP restores functional residual capacity and is similar to PEEP. The pressure in CPAP is continuously delivered during spontaneous breathing, thus preventing the patients’ airway pressure from falling to zero. It is indicated for patients who are capable of maintaining an adequate tidal volume, but who have pathology preventing maintenance of adequate levels of tissue oxygenation or for sleep apnea.

Advantages of CPAP1. Stabilization of upper airwayIncrease in FRC2. Decrease atelactasis3. Reduction in work of breathing in patients with intrinsic PEEP

Disadvantages of CPAP1. Air leaks2. Dynamic hyperinflation3. Pressure lesion on the skin4. Irritation of eyes5. Gastric distention6. Facial pain

NEWER MODES OF VENTILATION

INVERSE RATIO VENTILATION1. I:E ratio is greater than 1, in which inspiration is longer than expiration2. Used in patients with acute severe hypoxemic respiratory failure.3. Used with heavily sedated patients4. Used in ARDS and acute lung injury

Alternative ModesAlternative Modes• I:E inverse ratio ventilation (IRV)

• ARDS and severe hypoxemia• Prolonged inspiratory time (3:1)

leads to better gas distribution with lower PIP

• Elevated pressure improves alveolar recruitment

• No statistical advantage over PEEP, and does not prevent repetitive collapse and reinflation

• Prone positioning• Addresses dependent atelectasis• Improved recruitment and FRC,

relief of diaphragmatic pressure from abdominal viscera, improved drainage of secretions

• Logistically difficult• No mortality benefit demonstrated

• ECHMO• Airway Pressure Release (APR)

•High-Frequency Oscillatory Ventilation (HFOV)•High-frequency, low

amplitude ventilation superimposed over elevated Paw

•Avoids repetitive alveolar open and closing that occur with low airway pressures

•Avoids overdistension that occurs at high airway pressures

•Well tolerated, consistent improvements in oxygenation, but unclear mortality benefits

•Disadvantages• Potential hemodynamic

compromise• Pneumothorax• Neuromuscular blocking

agents

Vent settings to improve Vent settings to improve <ventilation><ventilation>•Respiratory rate

•Max RR at 35 breaths/min •Efficiency of ventilation

decreases with increasing RR• Decreased time for alveolar

emptying

•TV

•Goal of 10 ml/kg•Risk of volutrauma

•Other means to decrease PaCO2

•Reduce muscular activity/seizures

•Minimizing exogenous carb load•Controlling hypermetabolic

states

•Permissive hypercapnea•Preferable to dangerously high

RR and TV, as long as pH > 7.15

RR and TV are adjusted to maintain VE and PaCO2

•I:E ratio (IRV)• Increasing inspiration time

will increase TV, but may lead to auto-PEEP

•PIP•Elevated PIP suggests

need for switch from volume-cycled to pressure-cycled mode

•Maintained at <45cm H2O to minimize barotrauma

•Plateau pressures•Pressure measured at the

end of inspiratory phase•Maintained at <30-35cm

H2O to minimize barotrauma

Initial Settings

• Mode : SIMV with Pressure support (if available)• FiO2 : 1.0 (100%)• PEEP : 5• Tidal Volume : 6-7 ml / kg• Rate : 10-15 / minute• Pressure support : 15 cm H2O / If flow assist: 0.5 sec• Alarms : Max Pressure : 35 cm of H2O

: Min. pressure: 10 cm of H2O

Special consideration in the settings should be shown to COPD and ARDS patients.

ABG – After one hour and adjust the settings

Remember that • PaO2 depends on FiO2 & PEEP

• PaCO2 depends on Tidal volume & Rate

In ICU, our primary aim is • To get a PaO2 of 60-90 mmHg &

• PaCO2 of 30-50mmHg.

• Ensure that plateau inspiratory pressure does not exceed 30cm of H2O ( risk of VALI – Ventilator Associated Lung Injury)

Precaution & Care

• Tracheobronchial Hygiene:

• Placement of tube: Chest movementAuscultationPost intubation X-ray

• Cuff pressure: If insufficient- Leak Displacement of the tube Aspiration

If high pressure - Tracheal stenosis Desired Pressure - 20-30cm water

• Monitoring:

Continuous and Periodic monitoring of

• Vital parameters such as temperature,SpO2, Pulse, BP,ECG pattern, breath rate etc.

• Ventilator settings: All settings should be recorded – as per the doctors order

• Sensorium• Intake and output• Level of comfort• Arterial blood gases

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BUY “EASY TIGER” by RYAN ADAMS

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The ventilator also needs to be assessed to make sure that it is functioning properly and that the settings are appropriate. The nurse is responsible for the patient care, she needs to evaluate how the ventilator affects the patients overall status. In monitoring the ventilator the nurse should note the following:1. Type of ventilator:- volume cycled, pressure cycled, negative pressure2. Controlling mode:-controlled ventilation, assist control ventilation, synchronized intermittent mandatory ventilation3. Tidal volume and rate settings:- tidal volume is usually 10 to 15 ml/kg, rate is usually12 to 16/min4. Fraction of inspired oxygen setting

5. Inspiratory pressure reached and pressure limit:- normal is 15 to 20 cm H2o; this increases in conditions where there is increased airway resistance or decreased compliance6. Sensitivity:- a 2-cm H2O inspiratory force should trigger the ventilator7. Inspiratory- to expiratory ratio:- usually 1:3(1 second of inspiration to 3 seconds of expiration) or 1:28. Minute volume:- tidal volume × respiratory rate usually 6-8L/min9. Sigh settings:- usually 1.5 times the tidal volume and range from 1 to 3 per hour, if applicable10. Water in the tubing, disconnection or kinking of the tubing11. Humidification and temperature12. Alarms:- functioning properly or not13. PEEP and or/or pressure support level, if applicable, PEEP is usually 5 to 15 cm H2O

TROUBLESHOOTING

• Anxious Patient

– Can be due to a malfunction of the ventilator– Patient may need to be suctioned– Frequently the patient needs medication for anxiety or sedation

to help them relax

• Attempt to fix the problem

Low Pressure Alarm Usually due to a leak in the circuit. Cuff deflation, leak or rupture Upward migration of ET tube out of the larynx. Hypoventilation Large BPF with Cx drain in situ Ventilator dysfunction. Clogged HME

High Pressure Alarm• Usually caused by:

– A blockage in the circuit (water condensation)– Patient biting his ETT– Mucus plug in the ETT– ET tube obstruction– Bronchospasm– Low compliance due to- Pulmonary edema Pneumothorax Collapse of a lobe or lung

•Low oxygen concentration alarm -Upper oxygen concentration alarm -Apnea alarm- is activated if no attempt at breathing is made by the patient for atleast 15 seconds

NURSING CARE FOR THE PATIENT ON THE MECHANICAL

VENTILATOR

Nursing Care contd.• Record and document the

following settings per unit standards– Rate (mech and spont)– FiO2– Tidal volume (mech &

spont)– PS/PEEP/CPAP– Peak pressure (PIP)– SpO2

• NEVER use the top of the ventilator as a desk

• NEVER sit liquids on or near the ventilator

• NEVER make changes to ventilator settings

• Refer to RT, MD, NP, or Charge Nurse as needed

Care of the Ventilator Patient contd.• Observe and document

– Airway type, size, and position

– Character of insertion site

– Date airway inserted– Pulmonary assessment

• Inspection• Palpation• Percussion• Auscultation

• Provide oral care prn• Reapply ETT tape q24h and

prn• Provide trach care and

replace inner cannula q12h and prn

• Monitor for complications• Suction as needed• Wean and extubate

Eye & Mouth care • For unconscious patients eyes are

kept closed by taping.

• Goggles can also be used.

• Regular & proper mouth care should be given.

ASSESSMENTThe nurse has a vital role in assessing the patient’s status and the functioning of the ventilator. The nurse evaluates the patient’s physiologic status and psychological coping with mechanical ventilation.PHYSICAL ASSESSMENT It includes systematic assessment of all body systems, with in-depth focus on the respiratory system:1. Vital signs, 2. Respiratory rate and pattern, 3. Breath sounds4. Evaluation of spontaneous ventilator effort, 5. Potential evidence of hypoxia.6. Increased adventitious breath sounds may indicate a need for suctioning. 7. Assessing settings and functioning of mechanical ventilator.8. Comfort level and ability to communicate.9. Adequate nutrition being received or not10. Functioning of GIT and nutritional status. 

Impaired gas exchange related to underlying illness/

ventilator settings adjustment during stabilization or weaning

GOAL: Achievement of optimal gas exchange

NURSING INTERVENTIONS:-to enhance gas exchange 1. Provide adequate humidity via ventilator/nebulizer2. Frequent pulmonary auscultation every 1-2 hours3. Interpretation of ABGs measurement4. Continuously assess the patient for adequate gas exchange, signs of hypoxia and response to treatment5. Judicious administration of analgesics to relieve pain6. Frequent repositioning to prevent collection of secretions7. Monitor for adequate fluid balance by assessing peripheral edema and calculating intake output and monitoring daily weight8. Administration of medicines to control primary disease and monitor potential side effects 

NURSING DIAGNOSISIneffective airway clearance related to

increased mucus production associated with positive pressure ventilation

GOAL: Maintenance of patent airway

NURSING INTERVENTIONS 1. Identify presence of secretions every 2hourly2. Change patients position every 2 hourly and perform postural drainage, vibration and percussion maneuvers when indicated to prevent polling of secretions in the lungs3. Suctioning every 2 hourly to remove polled secretions4. Assess breath sounds every 2 hourly to monitor trends and effectiveness of interventions5. Administration of bronchodilator and mucolytic agents by intravenous or inhalation route6. Assess for adequate systemic hydration and provide supplemental humidification of ventilator delivered gases because these ill assist in thinning of secretions 

NURSING DIAGNOSISRisk for injury related to artificial

airways possible machine malfunction

NURSING INTERVENTIONS 1. Monitor for risk factors such as hypoxemia, hypercapnia, tachycardia, tachypnea etc.2. Begin mechanical ventilation slowly, lower PaCO2 only to patients baselines level o prevent alkalosis, especially in patients with compensated respiratory acidosis.3. Assess patients for possible causes of hyperventilation4. Check ventilator setting to determine if appropriate to clinical situations.5. Turn all alarms on; pause, but do not turn off alarms6. Monitor ventilator tubing every 2 hourly7. Use bite block or oral airway to keep patient from biting and obstructing the ET tube opening.8. Positioning the ventilator tubing so that there is minimal pulling or distortion of the tube in the trachea.

Risk for infection related to exposure to pathogens and loss of

normal protective barrier to infection

NURSING INTERVENTIONS1. Monitor for signs of infections; change in color, quantity, odor and viscosity of sputum.2. Obtain sputum for culture and sensitivity testing3. Keep head of bed elevated to prevent aspiration.4. Keep ventilator tubing cleared of condensed of water to eliminate source of infections5. Use sterile equipments and techniques with suctioning of reduce the risk of infections. 6. Administer anti-infective as ordered and monitor effectiveness.

Impaired physical mobility related to ventilator dependencyNURSING INTERVENTIONS1. Perform active or passive range of motion exercises to prevent muscle atrophy, contractures and venous stasis.2. Use foot board, high top sneakers and frequent foot flexion to prevent foot drop.3. Change patients position 2 hourly

Impaired verbal communication related to endotracheal tube and attachment to ventilator NURSING INTERVENTIONS1. Assess communication abilities and limitations2. Assess level of consciousness and responding to verbal commands and ability to write.3. Offer several appropriate communication options like pad and pencil, magic slate, gesturing communication board or electric larynx.4. Provide assistance of speech therapist.

Defensive coping and powerlessness related to ventilator dependency NURSING INTERVENTIONS 1. Encourage families to verbalize the fears about ventilator patient’s condition 2. Explain the procedures every time they are to be performed3. Encourage the patient o participate in decision about care, schedules and treatment when possible4. Inform about the progress of the patient5. Provide diversions like watching T. V., playing music etc.6. Use stress reduction technique like backrub and other relaxation measures.

Imbalanced nutrition less than body requirementNURSING INTERVENTIONS1. Provide enteral nutrition every 2 hourly2. Aspirate the content before every feed3. Provide high protein, high calorie feeds to the patient4. Assess the placement of the tube before each feed.

Risk for alteration in cardiac functions1. Monitor vital signs and level of consciousness

2. Monitor for signs and symptoms of hypoxia3. Monitor hemodynamic parameters to assess the patients status

Risk for barotraumas and Pneumothorax NURSING INTERVENTIONS1. Record level of peak inspiratory pressure to establish baseline data to evaluate changes in lung compliance2. Observe for sudden increase in peak pressure, sudden patient agitation or coughing, frequent activation of high pressure alarms, sudden change in oxygen saturation or respiratory distress3. Determine minimal tidal volume needed for adequate ventilation to limit risk of volume pressure trauma.4. Notify physician and set up for chest tube insertion immediately because Pneumothorax can convert to a life threatening tension Pneumothorax4. Check and record ventilator settings every 2 hourly to maintain accuracy.

Anxiety related to dependence on CMV for breathing, pain or fear of death and ICU environment

NURSING INTERVENTIONS1. Develop a means of communication2. Be available and visible3. Give simple and honest explanations regarding care and progress.4. Provide diversion therapy like music therapy etc. 5. Place a nurse call device within the client’s reach.6. Medicate as necessary.7. Respect client’s rights and opinions.

Impaired oral mucus membrane related to nothing by mouth status

NURSING INTERVENTIONS1. Provide oral hygiene every 2 hourly.2. Moisten mouth with solutions that do not contain alcohol or lemon as they may further dry mucus membrane.3. Moisten lips with lubricants to prevent drying, cracking or excoriation.4. Suction oral secretions.5. Assess for pressure areas at the time of the mouth from E/T tube.

Indications for extubationIndications for extubation

•Clinical parameters•Resolution/Stabilization of

disease process•Hemodynamically stable• Intact cough/gag reflex•Spontaneous respirations•Acceptable vent settings

•FiO2< 50%, PEEP < 8, PaO2 > 75, pH > 7.25

•General approaches•SIMV Weaning•Pressure Support

Ventilation (PSV) Weaning•Spontaneous breathing

trials• Demonstrated to be

superior

No weaning parameter completely accurate when used alone

Numerical Parameters Normal Range

Weaning Threshold

P/F > 400 > 200

Tidal volume 5 - 7 ml/kg 5 ml/kg

Respiratory rate 14 - 18 breaths/min

< 40 breaths/min

Vital capacity 65 - 75 ml/kg

10 ml/kg

Minute volume 5 - 7 L/min < 10 L/min

Greater Predictive Value Normal Range

Weaning Threshold

NIF (Negative Inspiratory Force)

> - 90 cm H2O

> - 25 cm H2O

RSBI (Rapid Shallow Breathing Index) (RR/TV)

< 50 < 100

.

Spontaneous Breathing TrialsSpontaneous Breathing Trials

•Settings

•PEEP = 5, PS = 0 – 5, FiO2 < 40%

•Breathe independently for 30 – 120 min

•ABG obtained at end of SBT•Failed SBT Criteria

•RR > 35 for >5 min

•SaO2 <90% for >30 sec

•HR > 140•Systolic BP > 180 or < 90mm

Hg•Sustained increased work of

breathing•Cardiac dysrhythmia•pH < 7.32

SBTs do not guarantee that airway is stable or pt can self-clear secretions Causes of Failed

SBTsTreatmentsTreatments

Anxiety/Agitation Benzodiazepines or haldol

Infection Diagnosis and tx

Electrolyte abnormalities (K+, PO4-)

Correction

Pulmonary edema, cardiac ischemia

Diuretics and nitrates

Deconditioning, malnutrition

Aggressive nutrition

Neuromuscular disease

Bronchopulmonary hygiene, early consideration of trach

Increased intra-abdominal pressure

Semirecumbent positioning, NGT

Hypothyroidism Thyroid replacement

Excessive auto-PEEP (COPD, asthma)

Bronchodilator therapy

).

CONCLUSIONThe knowledge of different kind of mechanical ventilators, their modes and the associated nursing implications will enable us to work more efficiently and with confidence. We will be able to work together with other team members and communicate effectively with them. We must continuously keep ourselves well informed about the latest technological advancement related to patient care, which will help us to extend and continue the nursing care in home settings as well.