Mechanical VentilationMechanical Ventilation

Dr. Abdul-Monim BatihaDr. Abdul-Monim Batiha

Assistant ProfessorAssistant ProfessorCritical Care NursingCritical Care Nursing

• Mechanical Ventilation is venti lation Mechanical Ventilation is venti lation of the lungs by art if icial means of the lungs by art if icial means usually by a ventilator. usually by a ventilator.

• A ventilator delivers gas to the A ventilator delivers gas to the lungs with either negative or lungs with either negative or positive pressure.positive pressure.

PurposesPurposes::

• To maintain or improve venti lation, To maintain or improve venti lation, & tissue oxygenation.& tissue oxygenation.

• To decrease the work of breathing To decrease the work of breathing & improve patient& improve patient ’’s comfort.s comfort.

IndicationsIndications::

1- 1- Acute respiratory failure due to:Acute respiratory failure due to:

• Mechanical failureMechanical failure, includes neuromuscular , includes neuromuscular diseases as Myasthenia Gravis, Guillain-Barré diseases as Myasthenia Gravis, Guillain-Barré Syndrome, and Poliomyelitis (failure of the Syndrome, and Poliomyelitis (failure of the normal respiratory neuromuscular system)normal respiratory neuromuscular system)

• Musculoskeletal abnormalitiesMusculoskeletal abnormalities, such as chest wall , such as chest wall trauma (flail chest)trauma (flail chest)

• Infectious diseasesInfectious diseases of the lung such as pneumonia, of the lung such as pneumonia, tuberculosis.tuberculosis.

2-2- Abnormalit ies of pulmonary gas Abnormalit ies of pulmonary gas exchangeexchange

as in:as in:

• Obstructive lung diseaseObstructive lung disease in the form of in the form of asthma, chronic bronchit is or asthma, chronic bronchit is or emphysema.emphysema.

• Conditions such as pulmonary edema, Conditions such as pulmonary edema, atelectasis, pulmonary f ibrosis.atelectasis, pulmonary f ibrosis.

• Patients who has received Patients who has received general general anesthesiaanesthesia as well as as well as post cardiac arrestpost cardiac arrest patients often require venti latory support patients often require venti latory support unti l they have recovered from the unti l they have recovered from the effects of the anesthesia or the insult of effects of the anesthesia or the insult of an arrest.an arrest.

Criteria for institution of Criteria for institution of venti latory supportventi latory support::

ParametersParameters Ventilation Venti lation indicatedindicated

Normal Normal rangerange

A- Pulmonary functionA- Pulmonary function

studiesstudies::

• Respiratory rate Respiratory rate (breaths/min).(breaths/min).• Tidal volume (ml/kgTidal volume (ml/kg body wt)body wt)• Vital capacity (ml/kg Vital capacity (ml/kg body wt)body wt)• Maximum InspiratoryMaximum Inspiratory Force (cm HOForce (cm HO2 ) )

< <3535

> >55

> >1515

->->2020

10-2010-20

5-75-7

65-7565-75

75-10075-100

Criteria for institution of Criteria for institution of venti latory supportventi latory support::

ParametersParameters Ventilation Venti lation indicatedindicated

Normal Normal rangerange

B- Arterial bloodB- Arterial blood GasesGases

• PHPH

• PaOPaO2 (mmHg) (mmHg)

• PaCOPaCO2 (mmHg) (mmHg)

> >7.257.25

> >6060

< <5050

7.35-7.457.35-7.45

75-10075-100

35-4535-45

Types of Mechanical Types of Mechanical venti latorsventi lators::

• Negative-pressure ventilators Negative-pressure ventilators

• Posit ive-pressure ventilators. Posit ive-pressure ventilators.

Negative-Pressure Venti latorsNegative-Pressure Venti lators

• Early negative-pressure ventilators Early negative-pressure ventilators were known as were known as ““iron lungs.iron lungs.””

• The patientThe patient ’’s body was encased in s body was encased in an iron cylinder and negative an iron cylinder and negative pressure was generated .pressure was generated .

• The iron lung are sti l l occasionally The iron lung are sti l l occasionally used today. used today.

• Intermittent short-term negative-pressure Intermittent short-term negative-pressure ventilation is sometimes used in patients ventilation is sometimes used in patients with chronic diseases. with chronic diseases.

• The use of negative-pressure ventilators The use of negative-pressure ventilators is restricted in clinical practice, however, is restricted in clinical practice, however, because because they l imit posit ioning and they l imit posit ioning and movement and they lack adaptabil ity to movement and they lack adaptabil ity to large or small body torsos (chests) .large or small body torsos (chests) .

• Our focus wil l be on the posit ive-pressure Our focus wil l be on the posit ive-pressure ventilators.ventilators.

Posit ive-pressure venti latorsPosit ive-pressure venti lators

• Posit ive-pressure ventilators deliver Posit ive-pressure ventilators deliver gas to the patient under positive-gas to the patient under positive-pressure, during the inspiratory pressure, during the inspiratory phase.phase.

Types of Posit ive-Pressure Types of Posit ive-Pressure Venti latorsVenti lators

1- 1- Volume Ventilators.Volume Ventilators.

2-2- Pressure Ventilators Pressure Ventilators

3-3- High-Frequency Ventilators High-Frequency Ventilators

• The volume venti lator is The volume venti lator is commonly usedcommonly used in crit ical care settings. in crit ical care settings.

• The basic principle of this venti lator is The basic principle of this venti lator is that that a designated volume of air is a designated volume of air is delivered with each breath.delivered with each breath.

• The amount of The amount of pressurepressure required to required to deliver the set volume deliver the set volume depends on :-depends on :-

- Patient- Patient ’’s lung compliance s lung compliance - Patient- Patient––venti lator resistance venti lator resistance

factors. factors.

1-1- Volume Venti lators Volume Venti lators

• Therefore, Therefore, peak inspiratory peak inspiratory pressure pressure (PIP )(PIP ) must be monitored must be monitored in volume modes because it varies in volume modes because it varies from breath to breath. from breath to breath.

• With this mode of venti lation, a With this mode of venti lation, a respiratory rate, inspiratory time, respiratory rate, inspiratory time, and tidal volume are selected for and tidal volume are selected for the mechanical breaths.the mechanical breaths.

• The use of pressure venti lators The use of pressure venti lators is is increasing increasing in crit ical care units. in crit ical care units.

• A typical pressure mode A typical pressure mode delivers a delivers a selected gas pressure to the patient selected gas pressure to the patient early in inspiration, and sustains the early in inspiration, and sustains the pressure throughout the inspiratory pressure throughout the inspiratory phase. phase.

• By meeting the patientBy meeting the patient ’’s inspiratory f low s inspiratory f low demand throughout inspiration, demand throughout inspiration, patient patient effort is reduced and comfort increased.effort is reduced and comfort increased.

2-2- Pressure Venti lators Pressure Venti lators

• Although Although pressure is consistentpressure is consistent with with these modes, volume is not. these modes, volume is not.

• Volume wil l change with changes in Volume wil l change with changes in resistance or compliance, resistance or compliance,

• Therefore, Therefore, exhaled tidal volume is the exhaled tidal volume is the variable to monitor closely. variable to monitor closely.

• With pressure modes, With pressure modes, the pressure level the pressure level to be delivered is selected, and with to be delivered is selected, and with some mode optionssome mode options (i.e., pressure (i .e., pressure controlled [PC], described later), controlled [PC], described later), rate rate and inspiratory t ime are preset as well.and inspiratory t ime are preset as well.

33- - High-Frequency Venti latorsHigh-Frequency Venti lators

• High-frequency venti lators High-frequency venti lators use use small t idal volumes (1 to 3 mL/kg) small t idal volumes (1 to 3 mL/kg) at frequencies greater than 100 at frequencies greater than 100 breaths/minute. breaths/minute.

• The high-frequency ventilator The high-frequency ventilator accomplishes oxygenation by the accomplishes oxygenation by the diffusion of oxygen and carbon diffusion of oxygen and carbon dioxide from high to low gradients dioxide from high to low gradients of concentration.of concentration.

• This diffusion movement is This diffusion movement is increased if the kinetic energy of increased if the kinetic energy of the gas molecules is increased.the gas molecules is increased.

• A high-frequency ventilator would A high-frequency ventilator would be used be used to achieve lower peak to achieve lower peak ventilator pressures, thereby ventilator pressures, thereby lowering the risk of barotraumalowering the risk of barotrauma ..

Classification of posit ive-Classification of posit ive-pressure venti latorspressure venti lators::

• Ventilators are classif ied according to Venti lators are classif ied according to how the inspiratory phase ends.how the inspiratory phase ends. The The factor which terminates the inspiratory factor which terminates the inspiratory cycle reflects the machine type. cycle reflects the machine type.

• They are classif ied as:They are classif ied as:

1- 1- Pressure cycled Pressure cycled venti latorventi lator

2-2- Volume cycled Volume cycled venti latorventi lator

3- 3- Time cycled venti latorTime cycled venti lator

11-- Volume-cycled venti latorVolume-cycled venti lator

• Inspiration is terminated after a Inspiration is terminated after a preset t idal volume has been preset t idal volume has been delivered by the ventilator. delivered by the ventilator.

• The ventilator delivers a preset The ventilator delivers a preset t idal volume (VT), and inspiration tidal volume (VT), and inspiration stops when the preset t idal volume stops when the preset t idal volume is achieved.is achieved.

22-- Pressure-cycled venti latorPressure-cycled venti lator

• In which inspiration is terminated In which inspiration is terminated when a specific airway pressure when a specific airway pressure has been reached. has been reached.

• The ventilator delivers a preset The ventilator delivers a preset pressure; once this pressure is pressure; once this pressure is achieved, end inspiration occurs.achieved, end inspiration occurs.

33- - Time-cycled venti latorTime-cycled venti lator

• In which inspiration is terminated In which inspiration is terminated when a preset inspiratory time, has when a preset inspiratory time, has elapsed. elapsed.

• Time cycled machines are not used Time cycled machines are not used in adult crit ical care settings. They in adult crit ical care settings. They are are used in pediatric intensive care used in pediatric intensive care areas.areas.

Venti lator modeVenti lator mode

• The way the machine ventilates the The way the machine ventilates the patient patient

• How much the patient wil l How much the patient wil l participate in his own ventilatory participate in his own ventilatory pattern. pattern.

• Each mode is different in Each mode is different in determining how much work of determining how much work of breathing the patient has to do.breathing the patient has to do.

Modes of Mechanical Venti lationModes of Mechanical Venti lation

A- A- Volume ModesVolume Modes

B- B- Pressure ModesPressure Modes

A- Volume ModesA- Volume Modes

1- 1- Assist-control Assist-control (A/C)(A/C)

2- 2- Synchronized intermittent Synchronized intermittent mandatory venti lation mandatory venti lation (SIMV)(SIMV)

1- Assist Control Mode A/C1- Assist Control Mode A/C• The venti lator provides the patient with a The venti lator provides the patient with a

pre-set tidal volume at a pre-set rate .pre-set tidal volume at a pre-set rate .

• The patient may The patient may init iate a breath on his init iate a breath on his ownown , but the , but the venti lator assists by venti lator assists by delivering a specif ied t idal volume to the delivering a specif ied t idal volume to the patient.patient. Client can init iate breaths that Client can init iate breaths that are delivered at the preset t idal volume.are delivered at the preset t idal volume.

• Client can breathe at a higher rate than Client can breathe at a higher rate than the preset number of breaths/minutethe preset number of breaths/minute

• The The total respiratory ratetotal respiratory rate is determined is determined by by the number of spontaneous inspiration the number of spontaneous inspiration init iated by the patientinit iated by the patient plus plus the number the number of breaths set on the venti lator.of breaths set on the venti lator.

• In A/C mode, a mandatory (or In A/C mode, a mandatory (or ““controlcontrol””) ) rate is selected.rate is selected.

• If the patient wishes to breathe faster, he If the patient wishes to breathe faster, he or she can or she can trigger the venti lator and trigger the venti lator and receive a full-volume breath.receive a full-volume breath.

• Often used as init ial mode of Often used as init ial mode of venti lat ionventilation

• When the patient is too weak to When the patient is too weak to perform the work of breathing (e.g., perform the work of breathing (e.g., when emerging from anesthesia).when emerging from anesthesia).

Disadvantages:Disadvantages:

• Hyperventi lation, Hyperventi lation,

22-- Synchronized Intermittent Synchronized Intermittent Mandatory Venti lation (SIMV Mandatory Venti lation (SIMV((

• The venti lator provides the patient with a pre-The venti lator provides the patient with a pre-set number of breaths/minute at a specif ied set number of breaths/minute at a specif ied t idal volume and FiOtidal volume and FiO 2 . .

• In between the venti lator-delivered breathsIn between the venti lator-delivered breaths , the , the patient is able to patient is able to breathe spontaneously at his breathe spontaneously at his own tidal volume and rateown tidal volume and rate with no assistance with no assistance from the venti lator.from the venti lator.

• However, unlike the A/C mode, However, unlike the A/C mode, any breaths any breaths taken above the set rate are spontaneous taken above the set rate are spontaneous breaths taken through the venti lator circuit .breaths taken through the venti lator circuit .

• The tidal volume of these breaths can The tidal volume of these breaths can vary drastically from the tidal volume set vary drastically from the tidal volume set on the venti latoron the venti lator , because the tidal , because the tidal volume is determined by the volume is determined by the patientpatient ’’s s spontaneous effort. spontaneous effort.

• Adding pressure supportAdding pressure support during during spontaneous breaths can spontaneous breaths can minimize the minimize the risk of increased work of breathing. risk of increased work of breathing.

• Ventilators breaths are Venti lators breaths are synchronizedsynchronized with with the patient spontaneous breathe.the patient spontaneous breathe.

( no f ighting)( no fighting)

• Used to wean the patient from the Used to wean the patient from the mechanical venti lator.mechanical venti lator.

• WeaningWeaning is accomplished by is accomplished by gradually lowering the set rate and gradually lowering the set rate and allowing the patient to assume more allowing the patient to assume more workwork

B- Pressure ModesB- Pressure Modes1-1- Pressure-controlled venti lation Pressure-controlled venti lation (PCV)(PCV) 2-2- Pressure-support venti lation Pressure-support venti lation (PSV)(PSV)

3-3- Continuous posit ive airway pressure Continuous posit ive airway pressure

(CPAP)(CPAP)

4- 4- Posit ive end expiratory pressure Posit ive end expiratory pressure (PEEP) (PEEP)

5-5- Noninvasive bilevel posit ive airway Noninvasive bilevel posit ive airway pressure venti lation pressure venti lation (BiPAP)(BiPAP)

1- Control Mode (CM)1- Control Mode (CM) Continuous Mandatory Continuous Mandatory Venti lationVenti lation ( CMV)( CMV)• Ventilation is completely provided by the Venti lation is completely provided by the

mechanical venti lator with mechanical venti lator with a preset t idal a preset t idal volume, respiratory rate and oxygen volume, respiratory rate and oxygen concentrat ionconcentrat ion

• Ventilator Venti lator totally controls the patienttotally controls the patient ’’s s venti lat ionventi lat ion i.e. the venti lator init iates and i.e. the venti lator init iates and controls both the volume delivered and the controls both the volume delivered and the frequency of breath.frequency of breath.

• Client does not breathe spontaneously.Client does not breathe spontaneously.

• Client can not init iate breatheClient can not init iate breathe

22- - Pressure-Controlled Pressure-Controlled Venti lat ion Mode Venti lat ion Mode ( PCV( PCV((

• The PCV mode is used The PCV mode is used

– If I f compliance is decreasedcompliance is decreased and and the risk of the risk of barotrauma is high.barotrauma is high.

– It is used when the patient has It is used when the patient has persistent persistent oxygenation problemsoxygenation problems despite a high FiO despite a high FiO 2 and high levels of PEEP. and high levels of PEEP.

• The inspiratory pressure level, respiratory rate, The inspiratory pressure level, respiratory rate, and inspiratoryand inspiratory ––expiratory (I :E) rat io must be expiratory (I :E) rat io must be selected.selected.

22- - Pressure-Controlled Pressure-Controlled Venti lat ion Mode Venti lat ion Mode ( PCV( PCV((• In pressure controlled ventilation the In pressure controlled ventilation the breathing gas flows under constant breathing gas flows under constant pressure into the lungs during the selected pressure into the lungs during the selected inspiratory time.inspiratory time.

• The flow is highest at the beginning of The flow is highest at the beginning of inspiration( i.e when the volume is lowest in inspiration( i.e when the volume is lowest in the lungs).the lungs).

• As the pressure is constant the flow is As the pressure is constant the flow is initially high and then decreases with initially high and then decreases with increasing filling of the lungs.increasing filling of the lungs.

• Like volume controlled ventilation PCV is Like volume controlled ventilation PCV is time controlled.time controlled.

Advantages of pressure Advantages of pressure limitations arelimitations are::

• 1- reduction of peak pressure and 1- reduction of peak pressure and therefore the risk of barotruma and therefore the risk of barotruma and tracheal injury. tracheal injury.

• 2- effective ventilation.2- effective ventilation.• Improve gas exchange Improve gas exchange

• Tidal volume varies with compliance and Tidal volume varies with compliance and airway resistance and must be closely airway resistance and must be closely monitoredmonitored . .

• Sedation and the use of neuromuscular Sedation and the use of neuromuscular blocking agentsblocking agents are frequently indicated, are frequently indicated, because any patientbecause any patient ––venti lator venti lator asynchrony usually results in profound asynchrony usually results in profound drops in the SaOdrops in the SaO 2 . .

• This is especially true when inverse This is especially true when inverse ratios are used. The ratios are used. The ““unnaturalunnatural”” feeling feeling of this mode often requires muscle of this mode often requires muscle relaxants to ensure patientrelaxants to ensure patient ––venti lator venti lator synchrony. synchrony.

• Inverse ratio venti lation (IRV) mode Inverse ratio venti lation (IRV) mode reverses this ratio so that reverses this ratio so that inspiratory inspiratory t ime is equal to, or longer than, t ime is equal to, or longer than, expiratory t ime (1:1 to 4:1). expiratory t ime (1:1 to 4:1).

• Inverse I:E ratios are used in conjunction Inverse I:E ratios are used in conjunction with pressure control with pressure control to improve to improve oxygenationoxygenation by expanding stiff alveoli by by expanding stiff alveoli by using longer distending times, thereby using longer distending times, thereby providing more opportunity for gas providing more opportunity for gas exchange and preventing alveolar exchange and preventing alveolar collapse.collapse.

• As expiratory t ime is decreased, one As expiratory t ime is decreased, one must monitor for the development of must monitor for the development of hyperinflation or auto-PEEP. Regional hyperinflation or auto-PEEP. Regional alveolar overdistension andalveolar overdistension and

barotrauma may occur owing to barotrauma may occur owing to excessive total PEEP.excessive total PEEP.

• When the PCV mode is used, the mean When the PCV mode is used, the mean airway and intrathoracic pressures rise, airway and intrathoracic pressures rise, potentially resulting in a decrease in potentially resulting in a decrease in cardiac output and oxygen delivery. cardiac output and oxygen delivery. Therefore, Therefore, the patientthe patient ’’s hemodynamic s hemodynamic status must be monitored closely.status must be monitored closely.

• Used to l imit plateau pressures that can Used to l imit plateau pressures that can cause barotrauma & Severe ARDScause barotrauma & Severe ARDS

33- - Pressure Support Venti lation Pressure Support Venti lation ( PSV( PSV((• The patient breathes spontaneously The patient breathes spontaneously while the venti lator while the venti lator applies a pre-applies a pre-determined amount of posit ive pressure determined amount of posit ive pressure to the airways upon inspiration.to the airways upon inspiration.

• Pressure support venti lation augments Pressure support venti lation augments patientpatient ’’s spontaneous breaths with s spontaneous breaths with posit ive pressure boost during inspirationposit ive pressure boost during inspiration i.e. assisting each spontaneous i.e. assisting each spontaneous inspiration.inspiration.

• Helps to overcome airway resistance and Helps to overcome airway resistance and reducing the work of breathingreducing the work of breathing ..

• Indicated for patients with Indicated for patients with small small spontaneous tidal volume and spontaneous tidal volume and diff icult to wean patients.diff icult to wean patients.

• Patient Patient must init iate all pressure must init iate all pressure support breaths.support breaths.

• Pressure support venti lat ion may be Pressure support venti lat ion may be combined with other modes such ascombined with other modes such as

SIMVSIMV or or used alone for a used alone for a spontaneously breathing patient.spontaneously breathing patient.

• The patientThe patient ’’s effort determines the s effort determines the rate, inspiratory flow, and tidal rate, inspiratory flow, and tidal volume. volume.

• In PSV mode, In PSV mode, the inspired tidal the inspired tidal volume and respiratory rate must be volume and respiratory rate must be monitored closelymonitored closely to detect changes to detect changes in lung compliance. in lung compliance.

• It is a mode It is a mode used primarily for used primarily for weaning from mechanical weaning from mechanical venti lation.ventilation.

• Constant posit ive airway pressureConstant posit ive airway pressure during during spontaneous breathingspontaneous breathing

• CPAP allows the nurse to observe the CPAP allows the nurse to observe the abil i ty of the patient to breathe abil i ty of the patient to breathe spontaneously while sti l l on the spontaneously while sti l l on the venti lator.venti lator.

• CPAP can be used CPAP can be used for intubated and for intubated and nonintubated patients.nonintubated patients.

• It may be used as It may be used as a weaning modea weaning mode and and for for nocturnal venti lationnocturnal venti lation (nasal or mask (nasal or mask CPAP)CPAP)

44- - Continuous Posit ive Airway Continuous Posit ive Airway Pressure (CPAP Pressure (CPAP((

55- - Posit ive end expiratoryPosit ive end expiratory pressure (PEEP pressure (PEEP((

• Posit ive pressure applied at the end Posit ive pressure applied at the end of expiration during mandatory \ of expiration during mandatory \ venti lator breathventilator breath

• positive end-expiratory pressure positive end-expiratory pressure with posit ive-pressure (machine) with posit ive-pressure (machine) breaths. breaths.

Uses of CPAP & PEEPUses of CPAP & PEEP• Prevent atelactasis or collapse of alveoliPrevent atelactasis or collapse of alveoli

• Treat atelactasis or collapse of alveoliTreat atelactasis or collapse of alveoli • Improve gas exchange & oxygenation Improve gas exchange & oxygenation • Treat hypoxemia refractory to oxygen Treat hypoxemia refractory to oxygen

therapy.(prevent oxygen toxicitytherapy.(prevent oxygen toxicity

• Treat pulmonary edema ( pressure help Treat pulmonary edema ( pressure help expulsion of f luids from alveoli expulsion of f luids from alveoli

66- - Noninvasive Bilateral Positive Noninvasive Bilateral Positive Airway Pressure Ventilation Airway Pressure Ventilation (BiPAP(BiPAP((

• BiPAP is a noninvasive form of BiPAP is a noninvasive form of mechanical venti lation mechanical venti lation provided by provided by means of a nasal mask or nasal prongs, means of a nasal mask or nasal prongs, or a full-face mask.or a full-face mask.

• The system allows the clinician to select The system allows the clinician to select two levels of posit ive-pressure supporttwo levels of posit ive-pressure support ::

• An inspiratory pressure support level An inspiratory pressure support level (referred to as IPAP) (referred to as IPAP)

• An expiratory pressure called EPAP An expiratory pressure called EPAP (PEEP/CPAP level). (PEEP/CPAP level).

Common Venti lator Sett ingsCommon Venti lator Sett ings parameters/ controls parameters/ controls

• Fraction of inspired oxygen (FIOFraction of inspired oxygen (FIO 2 ))• Tidal Volume (VT)Tidal Volume (VT)• Peak Flow/ Flow RatePeak Flow/ Flow Rate• Respiratory Rate/ Breath Rate / Respiratory Rate/ Breath Rate /

Frequency ( F)Frequency ( F)• Minute Volume (VE)Minute Volume (VE)• I:E Ratio (Inspiration to Expiration I:E Ratio (Inspiration to Expiration

Ratio)Ratio)• SighSigh

● ● Fraction of inspired oxygen Fraction of inspired oxygen (FIO(FIO2((

• The percent of oxygen concentration that the patient is receiving from the venti lator. (Between 21% & 100%)

(room air has 21% oxygen content).

• Init ial ly a patient is placed on a high level of FIO 2 (60% or higher).

• Subsequent changes in FIO 2 are based

on ABGs and the SaO 2.

• In adult patients the init ial FiO 2 may be set at 100% unti l arterial blood gases can document adequate oxygenation.

• An FiO 2 of 100% for an extended period of t ime can be dangerous ( oxygen toxicity) but i t can protect against hypoxemia

• For infants, and especially in premature infants, high levels of FiO 2 (>60%) should be avoided.

• Usually the FIO 2 is adjusted to maintain an SaO 2 of greater than 90% (roughly equivalent to a PaO 2 >60 mm Hg).

• Oxygen toxicity is a concern when an FIO 2 of greater than 60% is required for more than 25 hours

Signs and symptoms of oxygen toxicity :-Signs and symptoms of oxygen toxicity :-

1-1- Flushed face Flushed face

2- 2- Dry coughDry cough

3-3- Dyspnea Dyspnea

4-4- Chest pain Chest pain

5-5- Tightness of chest Tightness of chest

6-6- Sore throat Sore throat

● ● Tidal Volume (VTTidal Volume (VT((

• The volume of air delivered to a patient The volume of air delivered to a patient during a venti lator breath. during a venti lator breath.

• The amount of air inspired and expired The amount of air inspired and expired with each breath. with each breath.

• Usual volume selected is between Usual volume selected is between 5 to 5 to 15 ml/ kg body weight)15 ml/ kg body weight)

• In the volume venti lator, Tidal volumes of In the volume venti lator, Tidal volumes of 10 to 15 mL/kg of body weight were 10 to 15 mL/kg of body weight were tradit ionally used. tradit ionally used.

• the large tidal volumes may lead to the large tidal volumes may lead to (volutrauma)(volutrauma) aggravate the damage aggravate the damage infl icted on the lungsinfl icted on the lungs

• For this reason, lower tidal volume For this reason, lower tidal volume targets (6 to 8 mL/kg) are now targets (6 to 8 mL/kg) are now recommended.recommended.

● ● Peak Flow/ Flow RatePeak Flow/ Flow Rate• The speed of delivering air per unit The speed of delivering air per unit

of t ime, and is expressed in l i ters of t ime, and is expressed in l i ters per minute. per minute.

• The higher the flow rate, the faster The higher the flow rate, the faster peak airway pressure is reached peak airway pressure is reached and the shorter the inspiration;and the shorter the inspiration;

• The lower the f low rate, the longer The lower the f low rate, the longer

the inspiration.the inspiration.

● ● Respiratory Rate/ BreathRespiratory Rate/ Breath Rate / Frequency ( FRate / Frequency ( F((

• The number of breaths the venti lator wil l The number of breaths the venti lator wil l deliver/minute deliver/minute (10-16 b/m). (10-16 b/m).

• Total respiratory rate equals Total respiratory rate equals patient rate patient rate plus venti lator rate.plus venti lator rate.

• The nurse double-checks the functioning The nurse double-checks the functioning of the venti lator by observing the of the venti lator by observing the patientpatient ’’s respiratory rate.s respiratory rate.

For adult patients and older For adult patients and older children:- children:-

With COPDWith COPD

• A reduced tidal volume A reduced tidal volume • A reduced respiratory rateA reduced respiratory rate

For infants and younger children:-For infants and younger children:-

• A small t idal volumeA small t idal volume• Higher respiratory rateHigher respiratory rate

● ● Minute Volume (VEMinute Volume (VE((

• The volume of expired air in one The volume of expired air in one minute .minute .

• Respiratory rate times tidal volume Respiratory rate times tidal volume equals minute ventilation equals minute ventilation

VE = VE = (VT x F)(VT x F)

• In special cases, hypoventilation or In special cases, hypoventilation or

hyperventilat ion is desired hyperventilat ion is desired

In a patient with head injuryIn a patient with head injury , ,

• Respiratory alkalosis may be required to Respiratory alkalosis may be required to promote cerebral vasoconstriction, with a promote cerebral vasoconstriction, with a resultant decrease in ICP. resultant decrease in ICP.

• In this case, the t idal volume and In this case, the t idal volume and

respiratory rate are increased respiratory rate are increased ( hyperventi lation) to achieve the desired ( hyperventi lation) to achieve the desired

alkalotic pH by manipulating the PaCOalkalotic pH by manipulating the PaCO 2 . .

In a patient with COPDIn a patient with COPD • Baseline ABGs reflect an elevated PaCOBaseline ABGs reflect an elevated PaCO 2

should not hyperventi lated. Instead, the should not hyperventi lated. Instead, the goal should be restoration of the goal should be restoration of the baseline PaCObaseline PaCO 2 . .

• These patients usually have a large These patients usually have a large carbonic acid load, and lowering their carbonic acid load, and lowering their carbon dioxide levels rapidly may result carbon dioxide levels rapidly may result in seizures. in seizures.

● ● I :E Ratio (Inspiration toI:E Ratio (Inspiration to Expiration RatioExpiration Ratio(:-(:-

• The ratio of inspiratory time to The ratio of inspiratory time to expiratory time during a breath expiratory time during a breath

(Usually (Usually = 1:2)= 1:2)

● ● SighSigh• A deep breath. A deep breath.

• A breath that has a greater volume than the A breath that has a greater volume than the t idal volume.tidal volume.

• I t provides hyperinf lation and prevents It provides hyperinf lation and prevents atelectasis. atelectasis.

• Sigh volumeSigh volume :: ------------------Usual volume is 1.5 ------------------Usual volume is 1.5 ––2 t imes t idal volume.2 t imes t idal volume.

• Sigh rate/ frequency :Sigh rate/ frequency : ---------Usual rate is 4 to 8 ---------Usual rate is 4 to 8 t imes an hour.t imes an hour.

● ● Peak Airway PressurePeak Airway Pressure:-:-

• In adultsIn adults if the peak airway if the peak airway pressure is persistently pressure is persistently above 45 above 45 cmHcmH 2 O, the risk of barotrauma is O, the risk of barotrauma is increasedincreased and efforts should be and efforts should be made to try to reduce the peak made to try to reduce the peak airway pressure. airway pressure.

• In infants and childrenIn infants and children it is unclear it is unclear what level of peak pressure may what level of peak pressure may cause damage. cause damage. In general, keeping In general, keeping peak pressures below 30 is peak pressures below 30 is desirabledesirable . .

● ● Pressure LimitPressure Limit• On volume-cycled venti lators, the On volume-cycled venti lators, the

pressure l imit dial pressure l imit dial l imits the highest l imits the highest pressure allowed in the venti lator circuit.pressure allowed in the venti lator circuit.

• Once the high pressure l imit is reached, Once the high pressure l imit is reached, inspiration is terminated.inspiration is terminated.

• Therefore, if the pressure l imit is being Therefore, if the pressure l imit is being constantly reached, constantly reached, the designated tidal the designated tidal volume is not being delivered to the volume is not being delivered to the patient. patient.

● ● Sensit ivity(Sensit ivity( tr igger Sensitivitytrigger Sensitivity((

• The sensitivity function controls the The sensitivity function controls the amount of patient effort needed to amount of patient effort needed to init iate an inspirationinit iate an inspiration

• Increasing the sensit ivityIncreasing the sensit ivity (requiring less (requiring less negative force) negative force) decreases the amount of decreases the amount of workwork the patient must do to init iate a the patient must do to init iate a venti lator breath. venti lator breath.

• Decreasing the sensit ivity increases the Decreasing the sensit ivity increases the amount of negative pressureamount of negative pressure that the that the patient needs to init iate inspiration and patient needs to init iate inspiration and increases the work of breathing.increases the work of breathing.

• The most common setting for pressure The most common setting for pressure sensitivity are -1 to -2 cm Hsensitivity are -1 to -2 cm H22OO

• The more negative the number the harder The more negative the number the harder it to breath.it to breath.

Ensuring humidif ication and Ensuring humidif ication and thermoregulationthermoregulation• All air delivered by the venti lator passes All air delivered by the venti lator passes

through the water in the humidif ier, where it is through the water in the humidif ier, where it is warmed and saturated. warmed and saturated.

• Humidif ier temperatures should be kept close to Humidif ier temperatures should be kept close to body temperature body temperature 35 35 ººC- 37C- 37 ººC.C.

• In some rare instances (severe hypothermia), In some rare instances (severe hypothermia), the air temperatures can be increased. the air temperatures can be increased.

• The humidif ier should be The humidif ier should be checked for adequate checked for adequate water levelswater levels

• An empty humidifier contributes to drying An empty humidifier contributes to drying the airway, often with resultant dried the airway, often with resultant dried secretions, mucus plugging and less secretions, mucus plugging and less abil i ty to suction out secretions.abil i ty to suction out secretions.

• Humidif ier Humidif ier should not be overfi l ledshould not be overfi l led as as this may increase circuit resistance and this may increase circuit resistance and interfere with spontaneous breathing.interfere with spontaneous breathing.

• As air passes through the venti lator to As air passes through the venti lator to the patient, the patient, water condenses in the water condenses in the corrugated tubingcorrugated tubing . This moisture . This moisture is is considered contaminatedconsidered contaminated and and must be must be drained into a receptacle and not back drained into a receptacle and not back into the steri le humidif ier. into the steri le humidif ier.

• If the water is al lowed to build up, If the water is al lowed to build up, resistance is developed in the circuit and resistance is developed in the circuit and PEEP is generated. In addition, if PEEP is generated. In addition, if moisture accumulates near the moisture accumulates near the endotracheal tube, the patient can endotracheal tube, the patient can aspirate the water. aspirate the water.

• The nurse and respiratory therapist The nurse and respiratory therapist jointly are responsible for preventing this jointly are responsible for preventing this condensation buildup. The humidif ier is condensation buildup. The humidif ier is an ideal medium for bacterial growth. an ideal medium for bacterial growth.

Venti lator alarmsVenti lator alarms:-:-• Mechanical venti lators comprise Mechanical venti lators comprise audible audible

and visual alarm systemsand visual alarm systems , which act as , which act as immediate warning signals to altered immediate warning signals to altered venti lation. venti lation.

• Alarm systems can be categorized Alarm systems can be categorized according to volume and pressure (high according to volume and pressure (high and low). and low).

• High-pressure alarms warn of r ising High-pressure alarms warn of r ising pressures. pressures.

• Low-pressure alarms warn of Low-pressure alarms warn of disconnection of the patient from the disconnection of the patient from the venti lator or circuit leaks. venti lator or circuit leaks.

Complications Complications of Mechanical Venti lat ion:-of Mechanical Venti lat ion:-

I- I- Airway Complications,Airway Complications, II-II- Mechanical complications, Mechanical complications,

III-III- Physiological Complications, Physiological Complications,

IV-IV- Artif icial Airway Complications. Artif icial Airway Complications.

I- Airway ComplicationsI- Airway Complications

1-1- Aspiration Aspiration

2- 2- Decreased clearance of secretionsDecreased clearance of secretions

3-3- Nosocomial or venti lator-acquired Nosocomial or venti lator-acquired pneumoniapneumonia

I I- Mechanical complicationsII- Mechanical complications1-1- Hypoventi lation with atelectasis with respiratory Hypoventi lation with atelectasis with respiratory acidosis or hypoxemia.acidosis or hypoxemia.2- 2- Hyperventi lat ion with hypocapnia and Hyperventi lat ion with hypocapnia and

respiratory alkalosisrespiratory alkalosis3- 3- Barotrauma Barotrauma a- Closed pneumothorax, a- Closed pneumothorax, b- Tension pneumothorax, b- Tension pneumothorax, c- Pneumomediastinum, c- Pneumomediastinum, d- Subcutaneous emphysema.d- Subcutaneous emphysema.4-4- Alarm Alarm ““turned offturned off ””5- 5- Failure of alarms or venti latorFailure of alarms or venti lator6- 6- Inadequate nebulization or humidif icationInadequate nebulization or humidif ication7-7- Overheated inspired air, result ing in Overheated inspired air, result ing in

hyperthermiahyperthermia

III- Physiological ComplicationsIII- Physiological Complications

1-1- Fluid overload with humidif ied air and Fluid overload with humidif ied air and sodium chloride (NaCl) retentionsodium chloride (NaCl) retention2-2- Depressed cardiac function and Depressed cardiac function and hypotensionhypotension3- 3- Stress ulcersStress ulcers4- 4- Paralytic i leusParalytic i leus5-5- Gastric distension Gastric distension6-6- Starvation Starvation7-7- Dyssynchronous breathing pattern Dyssynchronous breathing pattern

IV- Artif icial Airway ComplicationsIV- Artif icial Airway ComplicationsA- Complications related toA- Complications related to

Endotracheal TubeEndotracheal Tube:-:-

1-1- Tube kinked or plugged Tube kinked or plugged2-2- Rupture of piri form sinus Rupture of piri form sinus3-3- Tracheal stenosis or tracheomalacia Tracheal stenosis or tracheomalacia4-4- Mainstem intubation with contralateral Mainstem intubation with contralateral

(( located on or affecting the opposite side of thelocated on or affecting the opposite side of the•lunglung) lung atelectasis) lung atelectasis

5-5- Cuff failure Cuff failure6-6- Sinusit is Sinusit is7- 7- Otit is mediaOtit is media8-8- Laryngeal edema Laryngeal edema

B- Complications related toB- Complications related to Tracheostomy tube Tracheostomy tube:-:-

1-1- Acute hemorrhage at the site Acute hemorrhage at the site2-2- Air embolism Air embolism3-3- Aspiration Aspiration4- 4- Tracheal stenosisTracheal stenosis5-5- Erosion into the innominate artery with Erosion into the innominate artery with

exsanguinationexsanguination6- 6- Failure of the tracheostomy cuffFailure of the tracheostomy cuff7-7- Laryngeal nerve damage Laryngeal nerve damage8-8- Obstruction of tracheostomy tube Obstruction of tracheostomy tube9- 9- PneumothoraxPneumothorax10- 10- Subcutaneous and mediastinal emphysemaSubcutaneous and mediastinal emphysema11- 11- Swallowing dysfunctionSwallowing dysfunction12-12- Tracheoesophageal f istula Tracheoesophageal f istula13- 13- InfectionInfection14-14- Accidental decannulation with loss of airway Accidental decannulation with loss of airway

Nursing care of patients on Nursing care of patients on mechanical venti lat ionmechanical venti lat ion

Assessment:Assessment:

1-1- Assess the patient Assess the patient

2-2- Assess the arti f icial airway Assess the arti f icial airway (tracheostomy(tracheostomy

or endotracheal tube)or endotracheal tube)

3-3- Assess the venti lator Assess the venti lator

Nursing InterventionsNursing Interventions1-1-Maintain airway patency & Maintain airway patency &

oxygenationoxygenation2-2- Promote comfort Promote comfort3-3- Maintain fluid & electrolytes Maintain fluid & electrolytes

balancebalance4- 4- Maintain nutrit ional stateMaintain nutrit ional state5- 5- Maintain urinary & bowel Maintain urinary & bowel

eliminationelimination6-6- Maintain eye , mouth and Maintain eye , mouth and

cleanliness and integrity:-cleanliness and integrity:-7-7- Maintain mobil ity/ musculoskeletal Maintain mobil ity/ musculoskeletal

function:-function:-

Nursing InterventionsNursing Interventions8-8- Maintain safety:- Maintain safety:-9- 9- Provide psychological supportProvide psychological support10-10- Facil itate communication Facil itate communication11- 11- Provide psychological support & Provide psychological support &

information to family information to family 12- 12- Responding to ventilator Responding to ventilator

alarms /Troublshootingalarms /Troublshooting venti lator alarmsventi lator alarms13- 13- Prevent nosocomial infectionPrevent nosocomial infection14- 14- DocumentationDocumentation

Responding To AlarmsResponding To Alarms• If an alarm sounds, respond immediately If an alarm sounds, respond immediately

because the problem could be serious. because the problem could be serious.

• Assess the patient f irstAssess the patient f irst , while you , while you silence the alarm.silence the alarm.

• If you can not quickly identify the If you can not quickly identify the problem, take the patient off the problem, take the patient off the venti lator and venti late him with a venti lator and venti late him with a resuscitation bag connected to oxygen resuscitation bag connected to oxygen source unti l the physician arrives.source unti l the physician arrives.

• A nurse or respiratory therapist must A nurse or respiratory therapist must respond to every venti lator alarm.respond to every venti lator alarm.

• Alarms must never be Alarms must never be ignored or disarmed.ignored or disarmed.

• Venti lator malfunction is a Venti lator malfunction is a

potential ly serious problem.potential ly serious problem. Nursing or respiratory Nursing or respiratory therapists perform venti lator therapists perform venti lator checks every 2 to 4 hours, and checks every 2 to 4 hours, and recurrent alarms may alert the recurrent alarms may alert the clinician to the possibi l i ty of an clinician to the possibi l i ty of an equipment-related issue. equipment-related issue.

• When device malfunction is When device malfunction is suspected, a second person suspected, a second person manually venti lates the patientmanually venti lates the patient while the nurse or therapist while the nurse or therapist looks for the cause. looks for the cause.

• If a problem cannot be promptly If a problem cannot be promptly corrected by venti lator corrected by venti lator adjustment, adjustment, a different machinea different machine is procured so the venti lator in is procured so the venti lator in question can be taken out of question can be taken out of service for analysis and repair service for analysis and repair by technical staff.by technical staff.

Causes of Venti lator Causes of Venti lator AlarmsAlarms

High pressure alarmHigh pressure alarm

• Increased secretionsIncreased secretions• Kinked ventilator tubing or Kinked ventilator tubing or

endotracheal tube (ETT)endotracheal tube (ETT)• Patient bit ing the ETTPatient bit ing the ETT• Water in the ventilator tubing.Water in the ventilator tubing.• ETT advanced into right mainstem ETT advanced into right mainstem

bronchus.bronchus.

Low pressure alarmLow pressure alarm

• Disconnected tubingDisconnected tubing• A cuff leakA cuff leak• A hole in the tubing A hole in the tubing (ETT or (ETT or

venti lator tubing)ventilator tubing)• A leak in the humidifierA leak in the humidifier

Oxygen alarmOxygen alarm • The oxygen supply is insufficient or is not The oxygen supply is insufficient or is not

properly connected.properly connected.

High respiratory rate alarmHigh respiratory rate alarm

• Episodes of tachypnea, • Anxiety,• Pain, • Hypoxia, • Fever.

-

Apnea alarmApnea alarm

• During weaning, indicates that the During weaning, indicates that the patient has a slow Respiratory rate patient has a slow Respiratory rate and a period of apnea. and a period of apnea.

Temperature alarmTemperature alarm

• Overheating due to too low or no Overheating due to too low or no gas flow.gas flow.

• Improper water levelsImproper water levels•

Methods of WeaningMethods of Weaning1-1- T-piece trial, T-piece trial,

2-2- Continuous Posit ive Airway Pressure Continuous Posit ive Airway Pressure (CPAP) weaning,(CPAP) weaning,

3-3- Synchronized Intermittent Mandatory Synchronized Intermittent Mandatory Venti lation (SIMV) weaning,Venti lation (SIMV) weaning,

4-4- Pressure Support Venti lation (PSV) Pressure Support Venti lation (PSV) weaning.weaning.

11- - T-Piece trialT-Piece trial• It consists of It consists of removing the patient from removing the patient from

the venti lator and having him / her the venti lator and having him / her breathe spontaneously on a T-tube breathe spontaneously on a T-tube connected to oxygen source. connected to oxygen source.

• During T-piece weaning, periods of During T-piece weaning, periods of venti lator support are alternated with venti lator support are alternated with spontaneous breathing.spontaneous breathing.

• The goal is The goal is to progressively increase the to progressively increase the time spent off the venti lator.t ime spent off the venti lator.

22--Synchronized Intermittent Synchronized Intermittent Mandatory Ventilation ( SIMV) Mandatory Ventilation ( SIMV) WeaningWeaning

• SIMV is the most common method of SIMV is the most common method of weaning. weaning.

• It consists of It consists of gradually decreasing the gradually decreasing the number of breaths delivered by the number of breaths delivered by the venti latorventi lator to allow the patient to increase to allow the patient to increase number of spontaneous breathsnumber of spontaneous breaths

33--Continuous Positive Airway Continuous Positive Airway Pressure ( CPAP) WeaningPressure ( CPAP) Weaning

• When placed on CPAP, When placed on CPAP, the patient does the patient does all the work of breathing without the aid all the work of breathing without the aid of a back up rate or tidal volume.of a back up rate or tidal volume.

• No mandatory (venti lator-init iated) No mandatory (venti lator-init iated) breaths are delivered in this mode i.e. al l breaths are delivered in this mode i.e. al l venti lation is spontaneously init iated by venti lation is spontaneously init iated by the patient.the patient.

• Weaning by gradual decrease in Weaning by gradual decrease in pressure valuepressure value

44- - Pressure Support Ventilation (PSV) Pressure Support Ventilation (PSV) Weaning Weaning• The patient must init iate all pressure support The patient must init iate all pressure support

breaths. breaths. • During weaning using the PSV mode During weaning using the PSV mode the level the level

of pressure support is gradually decreasedof pressure support is gradually decreased based on the patient maintaining an adequate based on the patient maintaining an adequate t idal volume (8 to 12 mL/kg) and a respiratory t idal volume (8 to 12 mL/kg) and a respiratory rate of less than 25 breaths/minute. rate of less than 25 breaths/minute.

• PSV weaning is indicated for :-PSV weaning is indicated for :-

- - Diff icult to wean Diff icult to wean patientspatients - - Small spontaneous t idal volume.Small spontaneous t idal volume.

Weaning readiness CriteriaWeaning readiness Criteria • Awake and alertAwake and alert

• Hemodynamically stable, adequately Hemodynamically stable, adequately resuscitated, and not requiring resuscitated, and not requiring vasoactive supportvasoactive support

• Arterial blood gases (ABGs) normalized Arterial blood gases (ABGs) normalized or at patientor at patient ’’s baselines baseline

- PaCO- PaCO 2 acceptable acceptable

- PH of 7.35 - PH of 7.35 –– 7.457.45

- PaO- PaO 2 > 60 mm > 60 mm Hg , Hg ,

- SaO- SaO 2 >92% >92% - FIO- FIO 2 ≤40% ≤40%

• Posit ive end-expiratory pressure Posit ive end-expiratory pressure (PEEP) ≤5 cm H(PEEP) ≤5 cm H 2 OO

• F < 25 / minuteF < 25 / minute• Vt 5 ml / kg Vt 5 ml / kg • VE 5- 10 L/m (f x Vt)VE 5- 10 L/m (f x Vt)• VC > 10- 15 ml / kg VC > 10- 15 ml / kg • PEP (positive expiratory pressure) PEP (positive expiratory pressure)

> - 20 cm H2O ( indicates patient> - 20 cm H2O ( indicates patient ’’s s abil ity to take a deep breath & abil ity to take a deep breath & cough),cough),

• Chest x-ray reviewed for Chest x-ray reviewed for correctable factors; treated as correctable factors; treated as indicated,indicated,

• Major electrolytes within normal Major electrolytes within normal range,range,

• Hematocrit >25%,Hematocrit >25%,• Core temperature >36°C and Core temperature >36°C and

<39°C,<39°C,• Adequate management of Adequate management of

pain/anxiety/agitation,pain/anxiety/agitation,• Adequate analgesia/ sedation Adequate analgesia/ sedation

(record scores on flow sheet),(record scores on flow sheet),• No residual neuromuscular No residual neuromuscular

blockade.blockade.

Role of nurse before Role of nurse before weaningweaning:-:-

1- Ensure that indications for the implementation 1- Ensure that indications for the implementation of Mechanical venti lat ion have improvedof Mechanical venti lat ion have improved

2- Ensure that all factors that may interfere with 2- Ensure that all factors that may interfere with successful weaning are corrected:-successful weaning are corrected:-

- Acid-base abnormalit ie - Acid-base abnormalit ie - Fluid imbalance- Fluid imbalance - Electrolyte abnormalit ies- Electrolyte abnormalit ies - Infection- Infection

- Fever- Fever - Anemia - Anemia - Hyperglycemia- Hyperglycemia - Protein - Protein - Sleep deprivation- Sleep deprivation

Role of nurse before Role of nurse before weaningweaning:-:-

3- Assess readiness for weaning 3- Assess readiness for weaning 4- Ensure that the weaning criteria / 4- Ensure that the weaning criteria /

parameters are met.parameters are met.5- Explain the process of weaning to the patient 5- Explain the process of weaning to the patient

and offer reassurance to the patient.and offer reassurance to the patient.

6- Init iate weaning in the morning 6- Init iate weaning in the morning when the patient is rested.when the patient is rested.

7- Elevate the head of the bed & Place 7- Elevate the head of the bed & Place the patient uprightthe patient upright

8- Ensure a patent airway and suction 8- Ensure a patent airway and suction if necessary before a weaning tr ial,i f necessary before a weaning tr ial,

9- Provide for rest period on venti lator 9- Provide for rest period on venti lator

for 15 for 15 –– 20 minutes after suctioning. 20 minutes after suctioning.

10- Ensure patient10- Ensure patient ’’s comfort & administer s comfort & administer pharmacological agents for comfort, such pharmacological agents for comfort, such

asas bronchodilators or sedatives as bronchodilators or sedatives as

indicated.indicated. 11- Help the patient through some of the 11- Help the patient through some of the discomfort and apprehension. discomfort and apprehension.

12- Support and reassurance help the patient12- Support and reassurance help the patient through the discomfort and apprehension through the discomfort and apprehension as remains with the patient after init iationas remains with the patient after init iation of the weaning process. of the weaning process.

13- Evaluate and document the patient13- Evaluate and document the patient ’’s s response to weaning.response to weaning.

Role of nurse during Role of nurse during weaningweaning:-:-

1-1- Wean only during the day. Wean only during the day.2-2- Remain with the patient during Remain with the patient during init iat ion of weaning.init iat ion of weaning.3-3- Instruct the patient to relax and breathe Instruct the patient to relax and breathe normally.normally.4-4- Monitor the respiratory rate, vital signs, Monitor the respiratory rate, vital signs, ABGs, diaphoresis and use of accessory ABGs, diaphoresis and use of accessory muscles frequently.muscles frequently.

I f signs of fatigue or respiratory distress develop. I f signs of fatigue or respiratory distress develop.

• Discontinue weaning tr ials.Discontinue weaning tr ials.

Signs of Weaning Intolerance CriteriaSigns of Weaning Intolerance Criteria

• Diaphoresis

• Dyspnea & Labored respiratory pattern

• Increased anxiety ,Restlessness, Decrease in level of consciousness

• Dysrhythmia,Increase or decrease in

heart rate of > 20 beats /min. or heart rate > 110b/m,Sustained heart rate >20% higher or lower than baseline

• Increase or decrease in blood pressure of > 20 mm Hg

Systolic blood pressure >180 mm Hg or <90 mm Hg

• Increase in respiratory rate of > 10 above baseline or > 30

Sustained respiratory rate greater than 35 breaths/minute

• Tidal volume ≤5 mL/kg, Sustained minute venti lation <200 mL/kg/minute

• SaO2 < 90%, PaO2 < 60 mmHg, decrease in PH of < 7.35.

Increase in PaCO 2

Role of nurse after Role of nurse after weaningweaning

1- Ensure that extubation criteria are1- Ensure that extubation criteria are met .met .

2- Decanulate or extubat2- Decanulate or extubat 2- Documentation 2- Documentation

Good LuckGood Luck