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Ventilator settings are ordered bythe physician and are individualized for each patient. Ventilators are designedto monitor many components of the patient’s respiratory status. Various alarmsand parameters can be set to warn healthcare providers that the patient ishaving difficulty with the settings.RespiratoryRate (RR)The respiratory rate is the number ofbreaths the ventilator delivers to the patient each minute. The rate chosendepends on the tidal volume, the type of pulmonary pathology, and the patient’starget PaCO 2. The respiratory rate parameters are set above andbelow this number and the alarm will then sound if the patient’s actual rate isoutside of the desired range.(The following are guidelines.) Forpatients with obstructive lung disease, the rate should be set at 6-8breaths/minute to avoid the development of auto-PEEP and hyperventilation, or“blowing off CO 2”. Patients with restrictive lung disease usuallytolerate a range of 12-20 breaths/minute. Patients with normal pulmonarymechanics can tolerate a rate of 8-12 breaths/minute.
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The patient should bemonitored on the initial rate setting and adjustments made as necessary.TidalVolume (VT)The tidal volume is the volume of gasthe ventilator delivers to the patient with each breath. The tidal volumeparameters are set above and below the desired number, and the alarm will soundif the patient’s actual tidal volume is outside of the desired range. This isespecially helpful if the patient is breathing spontaneously betweenventilator-delivered breaths, since the patient’s own tidal volume can becompared with the tidal volume delivered by the ventilator.The usual setting is 5-15 cc/kg,based on compliance, resistance, and type of pathology. Patients with normallungs can tolerate a tidal volume of 12-15 cc/kg, whereas patients withrestrictive lung disease may need a tidal volume of 5-8 cc/kg.FractionalInspired Oxygen (FiO 2)The fractional inspired oxygen is theamount of oxygen delivered to the patient. It can range from 21% (room air) to100%. It’s recommended that the FiO 2 be set at 1.0 (100%) upon theinitiation of mechanical ventilation to allow the patient to get used to theventilator without experiencing hypoxia.
However, 100% oxygen should not beused continuously for long periods of time because of the risk of oxygentoxicity. Oxygen toxicity causes structural changes at the alveolar-capillarymembrane, pulmonary edema, atelectasis, and decreased PaO 2. Once thepatient is stabilized, the FiO 2 can be weaned down based on pulseoximetry and arterial blood gas values.
The FiO 2 should only be ashigh as is necessary to keep the PaO 2 in the desired range.Most ventilators have a temporary100% oxygen setting that delivers 100% oxygen for only a few breaths. Thisshould always be used prior to and after suctioning; during bronchoscopy, chestphysiotherapy, or other stressful procedures; and during patient transport.Inspiratory:Expiratory (I: E) RatioThe I: E ratio is usually set at 1:2or 1:1.5 to approximate the normal physiology of inspiration and expiration.Occasionally, a longer inspiratory than expiratory time is desired to allowmore time to oxygenate the patient’s lungs. This is called inverse ratioventilation, and will be discussed later.PressureLimitThe pressure limit regulates theamount of pressure the volume-cycled ventilator can generate to deliver thepreset tidal volume. Because high pressures can cause lung injury, it’srecommended that the plateau pressure not exceed 35 cm H 2O.
If thislimit is reached, the ventilator stops delivering the breath and alarms. Thismay be an indication that the patient’s airway is obstructed with mucus, inwhich case, the high pressure is usually resolved with suctioning. It can alsobe caused by the patient coughing, biting on the ETT, breathing against theventilator, or by a kink in the ventilator tubing.FlowrateThe flow rate is the speed with whichthe tidal volume is delivered. The usual setting is 40-100 liters per minute.Sensitivity/TriggerThe sensitivity determines the amountof effort required by the patient to initiate inspiration. It can be set to betriggered by pressure or flow. Flow triggering is a better setting for patientswho can breathe spontaneously because it reduces the work of breathing.SighThe ventilator can beprogrammed to deliver an occasional sigh with a larger tidal volume. The use offrequent sighs was popular during the 1970s because it was thought that itprevented collapse of the alveoli (atelectasis), which can result from thepatient constantly inspiring the same volume of gas.
DisadvantageThe major disadvantage ofCMV is that it is not synchronized with the efforts of the patient. When thepatient is “out of sync” with the ventilator, he attempts to exhale as theventilator is in the inspiratory phase. As a result, airway pressure builds toabnormally high levels and the remainder of the inspiratory volume is notdelivered. This “bucking” causes a high-pressure alarm. Signs and symptoms ofventilator dys-synchrony include:. Agitation.
Diaphoresis. Tachycardia.
Tachypnea. Paradoxicalthoraco-abdominal breathing pattern. IncreasedPIP (peak inspiratory pressure)Assist Control (A/C)Ventilation TheA/C mode is similar to CMV, but it allows the patient to trigger an assistedbreath at any time.
A/Cdelivers the pre-set volumes at a pre-set rate and a pre-set flow rate inresponse to the patient’s own inspiratory effort, but will initiate the breathif the patient does not do so within the set amount of time. Thepatient CANNOT generate spontaneous volumes, or flow rates in this mode.
Alldelivered breaths, whether mandatory or patient-triggered, will be delivered bythe ventilator according to the set parameters. All breaths in theassist-control mode receive the same FiO 2 and tidal volume. Hyperventilationand respiratory alkalosis may result from occurrences that increase thepatient’s spontaneous rate such as anxiety or neurological factors. A highsensitivity setting that causes the machine to cycle too frequently can alsocause this problem. An increased risk of air trapping with high respiratoryrates may also potentially occur with the A/C ventilation. TheA/C rate is the minimum number of full ventilator breaths the patient willreceive.
The actual respiratory rate is equal to the A/C rate plus anypatient-triggered breaths per minute. Thismode is used for patients who can initiate a breath but who have weakenedrespiratory muscles.
Intermittent MandatoryVentilation (IMV) & Synchronous IMV (SIMV)IMV IMV isthe most commonly used modes of ventilation. Inthis mode the ventilator delivers a preset rate, tidal volume (or inspiratorypressure) and FiO2. Thepatient may also draw spontaneous breaths in-between mandatory breaths. UnlikeA/C, breaths that the patient takes spontaneously do not trigger or cycle theventilator. Patient-initiatedbreaths are completely spontaneous, neither assisted nor supported by theventilator.
SIMV SIMVwas developed as a result of the problem of high respiratory rates associatedwith A/C. SIMVdelivers the preset volume or pressure and rate while allowing the patient tobreathe spontaneously in between ventilator breaths. Each ventilator breath isdelivered in synchrony with the patient’s breaths, yet the patient is allowedto completely control the spontaneous breaths. SIMV allowsthe patient to generate spontaneous breaths, volumes, and flow rates betweenthe set breaths. SIMVis used as a primary mode of ventilation, as well as a weaning mode. Duringweaning, the preset rate is gradually reduced, allowing the patient to slowlyregain breathing on his or her own.
Advantages Maintainsrespiratory muscle strength by avoiding muscle atrophy Decreasesmean airway pressure Facilitatesventilator discontinuation – “weaning” Decreasedchance of hyperventilation, Decreasedatrophy of accessory muscles, and Improveddistribution of gas throughout the lungs by the action of the diaphragm.Disadvantages Thismode may increase the work of breathing and respiratory muscle fatigue. In IMVmode the mechanical rate and spontaneous rate may asynchronous causing“stacking” and that may cause barotrauma or volutraumaSpontaneous Modes ORCustomized Adjuncts to Ventilator ModesPEEP (Positive EndExpiratory Pressure) Accordingto its purest definition, the term PEEP is defined as positive pressure at theend of exhalation during either spontaneous breathing or mechanicalventilation. However, use of the term commonly implies that the patient isalso receiving mandatory breaths from a ventilator. Onemethod of improving the patient’s oxygenation without increasing the FiO 2is the use of PEEP. Basically, PEEP does not allow airway pressure to return tozero at the end of expiration.
PEEPis not a mode of ventilation in itself. It is an adjunctive therapy added toother modes. It is intended to improve oxygenation, not to provide ventilation,which is the movement of air into the lungs followed by exhalation PEEPis added to increase functional residual capacity (FRC) and allow for adecrease in the FiO 2.
PEEP helps to prevent small airway andalveolar collapse, improves alveolar ventilation and may decrease the work ofbreathing (at low levels). PEEP facilitates oxygen diffusion at lower FiO 2levels, which is safer for the patient. PEEPof 5cm H 2O pressure is referred to as “physiologic” PEEP because itis equivalent to the effect of the closed glottis. Therapeutic PEEP usuallyranges from 10-30cm H 2O in adults. PEEPis an effective therapy for disease processes involving atelectasis; it is acornerstone of therapy for ARDS.Disadvantage Decreasedcardiac output with or without hypotension occurs because PEEP increasesintra-thoracic pressure, which in turn decreases the venous return to the heart(preload).
Potentialvolutrauma and barotrauma, Increasedintracranial pressure and Potentialloss of tidal volumeContinuous PositiveAirway Pressure (CPAP) CPAPis similar to PEEP except that it works only for patients who are breathingspontaneously. CPAPis PEEP with no set rate on the ventilator. CPAP is primarily used as a mode ofnon-invasive mechanical ventilation.
It is occasionally used in the finalstages of ventilator weaning, but has minimal application for the mechanicallyventilated patient. Patientson CPAP do not receive positive pressure breaths from the ventilator.
Allbreaths are initiated and ended by the patient; tidal volumes and pressures arevariable from breath to breath. CPAPcan also be administered using a mask and CPAP machine for patients who do notrequire mechanical ventilation, but who need respiratory support; for example,patients with sleep apnea. CPAPaids in promotion of oxygenation in the same way PEEP does. It has no influenceon ventilation.Advantage Ventilatorcan monitor the patient’s breathing and activate an alarm if somethingundesirable occurs Helpfulfor improving oxygenation in patients with refractory hypoxemia and a low FRC CPAPsetting is adjusted to provide the best oxygenation with the lowest positivepressure and the lowest FiO 2. BrunnerLS, Suddarth DS, Smeltzer SCO. Brunner & Suddarth’s textbook ofmedical-surgical nursing. Philadelphia: Lippincott Williams & Wilkins;2008.
NettinaSM, Lippincott Williams & Wilkins. Lippincott manual of nursing practice.Philadelphia: Wolters Kluwer Health: Lippincott Williams & Wilkins;2010. LongoDL, Harrison T.
Harrison’s principles of internal medicine. New York, N.Y.,etc.: McGraw-Hill Medical; 2012. ColledgeNR, Walker BR, Ralston S, Davidson S. Davidson’s principles and practice ofmedicine. Edinburgh; New York: Churchill Livingstone/Elsevier; 2010.
AdultInvasive Mechanical Ventilation.pdf Internet. cited 2012 May 28. Availablefrom: AdultVentilation Management Online Nursing Continuing Education Course Internet.cited 2012 May 28. Available from: CriticalCare Nursing Theory - Mechanical ventilation Internet. cited 2012 May 28.Available from: PatientEducation Series American Thoracic Society Mechanical Ventilation Internet.cited 2012 May 28.
Available from: CoreTopics in Mechanical Ventilation Internet. cited 2012 May 28. Availablefrom: Fundamentalsof Mechanical Ventilation Internet. cited 2012 May 28. Available from: MechanicalVentilation Critical Care Clinic Internet. cited 2012 May 28. Availablefrom: MechanicalVentilation for Nursing.ppt Internet.
cited 2012 May 28. Available from: Mechanicalventilation Skills and techniques Update 2011 Internet. cited 2012 May 28.Available from: MechanicalVentilation.ppt Internet. cited 2012 May 28.
Available from: MechanicalVentilation.ppt Internet. cited 2012 May 28. Available from: Modesof Ventilation ppt Internet. cited 2012 May 28. Available from: Nursingcare of the mechanically ventilated patient: What does the evidence say?
cited 2012 May 28. Available from:NursingCare Of The Ventilated Patient Internet. cited 2012 May 28. Available from:Principleof Mechenical Ventilation Internet. cited 2012 May 28.
Available from: Chapter82 - Mechanical Ventilation Internet. cited 2012 May 28. Available from: respiratory-failure-mechanical-ventilation.pdfInternet. cited 2012 May 28. Available from: AdvancesIn Mechanical Ventilation Internet.
cited 2012 May 28. Available from: Standardof Practice: Care of the Mechanically Ventilated Patient Internet. cited2012 May 28. Available from: InvasiveMechanical Ventilation ppt Internet.
cited 2012 May 28. Available from: Managementof the mechanically ventilated. Patient in the emergency department Internet.cited 2012 May 28. Available from: MechanicalVentilation: A Review and Update for Clinicians Internet. cited 2012 May28.
Available from: How toWithdraw Mechanical Ventilation Internet. cited 2012 May 28. Availablefrom: Mechanicalventilation: Weaning and extubation Internet. cited 2012 May 28. Availablefrom: Withdrawalof Ventilatory Support from the Dying Adult Patient Internet. cited 2012 May28.
Available from: http://jso.imng.com/jso/journal/articles/0203283.pdf.