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1/17/2012 Objectives • Identify types of airways and indications Understanding Mechanical Ventilation and its Implications for Physical Therapy Intervention • Identify common modes of ventilation and describe the assistance that each mode provides • Interpret common alarms associated with mechanical ventilation and indicate actions • Describe possible complications associated with mechanical ventilation Jennifer M. Zanni, PT, DScPT Clinical Specialist, Johns Hopkins Hospital Lecturer, Johns Hopkins University 2 1 Why is mechanical ventilation required?? required Objectives • One of the most common indications for using mechanical ventilation is to decrease the work of the respiratory musculature and improve arterial oxygenation • Discuss and synthesize common weaning parameters and methods • Describe treatment strategies for mobilizing the patient requiring mechanical ventilation • Patients in acute respiratory failure can have 46x the normal inspiratory effort • Discuss current literature regarding rehabilitation of patients requiring mechanical ventilation • Careful selection of vent support and settings is crucial and needs to be individualized to each patient Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001 1/17/2012 3 Why is mechanical ventilation required?? required 4 Why is mechanical ventilation required?? required • In a study of 1638 patients (8 countries) who required mech vent: • Impending or existing respiratory failure – Failure to oxygenate – Failure to Ventilate – Or combination of the two – Acute Respiratory Failure (66%) • ALI/ARDS, heart failure, pneumonia, sepsis, trauma, surgery complications – Coma (15%) – Acute on chronic COPD (13%) – Neuromuscular disorders (5%) • Airway protection Esteban, A et al. Am J Respir Crit Care Med. 2000;161:1450-8. Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001 5 1 1/17/2012 Failure to Ventilate Failure to Oxygenate • Hypercapnic Respiratory Failure • Hypoxic Respiratory Failure – Caused by disorders of CNS, neuromuscular systems, chest wall or airways – Increased PaCO2 > 50 mmHg – s/s include tachypnea, agitation, cyanosis, and decreased mental status • Inadequate exchange of gases at the alveolar level, as seen in ARDS • Decreased PaO2 (<50 mmHg) – Can occur despite normal ventilation – Occurs at pulm-alveolar interface due to pulm edema or fibrosis – Reduced diffusing capacity and V/Q mismatch 8 7 Acute Lung Injury/ Injury/ Acute Respiratory Distress Syndrome Failure to Oxygenate A big challenge in mech ventilation are in alveolar-filling disorders (ALI/ARDS) causing pulm edema and stiffness in the lungs, making them difficult to ventilate • Clinical presentation – Acute onset – Bilateral infiltrates – Severe dyspnea and tachypnea – Hypoxemia • PaO2/FiO2 < 300 (ALI) • PaO2/FiO2 < 200 (ARDS) • Can be caused by a variety of factors, usually inflammatory in nature Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001 – Pulmonary (pneumonia) vs. extra pulmonary (sepsis) 9 Fan E et al., JAMA 2005;294:2889-2896. Respiratory Failure • Patients at risk for alveolar rupture from mech vent • Benefits have been shown with using lower tidal volumes • May benefit from prone positioning to allow ventilation to be distributed more evenly throughout the lungs Types of Ventilation Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001 11 12 2 1/17/2012 Positive vs. Negative Pressure Ventilation Things to consider… • Negative Pressure • What type of airway is in place? • What are the ventilator settings and what do they all mean? • What do I do if the vent alarms? • What to I do if the vent fails? • How do I plan treatment in conjunction with vent weaning? – Mimics more normal chest mechanics with respiration – Assists with failure of ventilation, but not oxygenation – “Iron lung • Positive Pressure – Most common – Opposite of “normal” breathing http://www.ccmtutorials.com/rs/mv/page4.htm Accessed on 12/2/11 13 Airway Management • Endotracheal Tube (ETT) Start with the ABC’s… Airway • Can be placed orally (most common) or nasally • Passes through the vocal cords Airway Management Airway Management • Tracheostomy tube • Cuff vs Cuffless • Inserted below the vocal cords • Used in more longterm airway management • Airway cuffs: – Assists with holding the airway in place – Allows positive pressure ventilation without loss of tidal volume – May reduce risk of aspiration of oral and gastric secretions – If pt can talk or is losing tidal volume…cuff may not be fully inflated 3 1/17/2012 Challenges to Mechanical Ventilation Ventilator Settings • • • • • • Tidal volumes too large can over-inflate lungs and cause alveolar damage Tidal Volume PEEP Mode Rate FiO2 • Tidal volumes too small may increase dead space • The goal is to use vent settings to optimize gas exchange without damaging the lungs • Unfortunately, there is no evidence to support one ideal mode or setting of mech ventilation 20 Actual resp rate PEEP • Type of respiration Positive End-Expiratory Pressure – – – – Mode & Rate FiO2 PEEP Pressure given in expiratory phase to prevent closure of the alveoli and allow increased time for O2 exchange Used in pts who haven’t responded to treatment and are requiring high amt of FiO2 PEEP will lower O2 requirements by recruiting more surface areas Normal PEEP is approximately –5cmH20. Can be as high as –20cmH20 – Risks include barotrauma, ptx, and decreased cardiac output Oxygen Therapy • Prolonged exposure to high levels of oxygen can be toxic to the lungs • High FiO2 (>.5) can lead to atelectasis Modes of Ventilation • Balancing act between FiO2 and PEEP 4 1/17/2012 Modes of Ventilation • Controlled Ventilation Modes of Ventilation • Assist Control (A/C) – Vent provides a preset resp rate, TV, and inspiratory flow rate – Will allow a pt to initiate a breath and then vent will deliver a preset tidal volume – Machine set at a minimum rate so apnea will not occur if the pt does not initiate a breath – Disadvantages: • Hyperventilation if pt has increased resp rate (can lead to resp alkalosis) • Vent dysynchrony, breath-stacking – Vent initiates all breaths at a preset rate and tidal volume – Vent will block any spontaneous breaths – Used mainly in the OR for paralyzed and sedated patients. Modes of Ventilation • Synchronized Intermittent Ventilation (SIMV) Modes of Ventilation • Pressure Support Ventilation (PSV) – Pt initiates breath & vent delivers a preset inspiratory pressure to help overcome airway resistance – Patient controls the rate, tidal volume, flow rate and duration of inspiration – Pts may be more comfortable on PS – Tidal volume is variable – Can be used in conjunction with SIMV or CPAP settings – Similar to A/C, but pts can take own breaths with their own TV between mechanically assisted breaths – Can be used as a primary mode or a weaning mode – May lead to a low resp rate in a pt who does not initiate breaths if rate is set low Modes of Ventilation • Pressure Support Ventilation (PSV) – – – Higher amounts of PS needed when lung compliance is decreased or airway resistance is high or when the patient can only make weak inspiratory efforts PS 5 (low amount) PS 10 or greater (high amount) – Commonly used as a weaning mode Modes of Ventilation • Pressure Control (PC) – – – Similar to pressure support, but a preset resp rate is set if the patient is not spontaneously breathing If the pt is spontaneously breathing, this will function similar to pressure support May be used in ALI/ARDS to avoid barotrauma 5 1/17/2012 Modes of Ventilation • Continuous Positive Airway Pressure (CPAP) – Constant positive airway pressure provided during both inspiration and expiration – Vent provides O2 and alarms, but no respirations – Improves gas exchange and oxygenation in pts able to breathe on their own – Can also be used non-invasively via a face or nasal mask for sleep apnea pts Non--Invasive Ventilation (NIV) Non • Bi-Level Airway pressure (BiPAP) – Delivered by mask, not through an airway – Similar to CPAP, but can be set at one pressure for inhalation and another for exhalation. – Used in sleep apnea but also has been found to be useful in some patients with respiratory failure to avoid intubation Non-Invasive Ventilation (NIV) Non-Invasive Ventilation (NIV) • Allows the patient to be able to speak and eat • Avoids the risks associated with intubation, sedation • No protection against aspiration • Used in decompensated COPD, CHF, hypoxic and hypercapnic respiratory failure, DNI patients • Some emerging evidence in a few small studies that in patients with severe COPD, exercise while on NIV improves 6 MWT, LE muscle fatigue, and oxidative threshold when compared to the use of supplemental O2 alone Borghi-Silva A, et al. Respiratory Care. July 2010(58)7, pp. 885-894. Toledo A, et al. Clinics (Sao Paulo). 2007; 62(2):113-20 Borghi-Silva A, et al. Respirology. 2009, 14, pp. 537-544 Modes of Ventilation • High frequency oscillatory ventilation (HFOV) – Sets a mean airway pressure, but minimal change in tidal volume – Airway pressure is set so that alveoli remain open and “oscillate” – Small tidal volumes minimize barotrauma – Inspiratory and expiratory phase are both active – Was used primarily in neonates, but now also being used in adults with ARDS/ALI. – Goal is to wean back to regular mech vent Modes of Ventilation • Airway Pressure Release Ventilation (APRV) – Differs from conventional vent – Cycles between 2 levels of airway pressures to assist with gas exchange – Elevation of airway pressures with brief intermittent releases of airway pressure – Facilitates oxygenation and CO2 clearance – May be an improved way to treat ALI/ ARDS 6 1/17/2012 Vent Alarms • Vent Alarms High Pressure Alarm (common alarm to come and go…more serious if it continues to alarm) – – – – – – – • – Pt pops off vent – Leak in cuff or tubing connections (if patient can talk around trach, a leak in the cuff is probable) – Extubation Secretions/ needs to be suctioned Pt biting tube/ fighting vent Water in tubing Bronchospasm Pneumothorax Decreased compliance (i.e. ARDS) Kinked tubing/ malposition of ETT Vent Alarms • Other Alarms – – – – – Tidal volume (high, low) Resp rate (high, low, apnea Temperature Oxygen supply Power Vent Alarms • General principles… – Look at the pt first!!! Then follow tubing to the vent to search for any disconnections – If can’t find the problem and the patient is in distress, disconnect the patient from the vent and bag with 100% O2 (and call for help) Complications of Mech Vent • • Asynchrony (“bucking”) Auto PEEP – Pt doesn’t expire full tidal volume and air become trapped • Barotrauma – Damage to alveoli caused by increased pressure and volume Low Exhaled Volume/ Circuit Disconnect Alarm Complications of Mech Vent • • • • • • Hemodynamic compromise Nosocomial infection Anxiety/ Stress/ Sleep deprivation Ulcers/ Gastritis/ Malnutrition Muscle deconditioning/ Vent dependence Increased intrathoracic pressure can cause systemic edema due to decreased venous return 7 1/17/2012 Weaning Parameters • Weaning is one of the most challenging tasks in the ICU • Up to 25% of patients will have resp distress requiring re-initiation of mech vent support Weaning Parameters • However, a patient’s ability to breathe on their own is often underestimated • 50% of patients who self-extubate do not require reintubation Epstein, SK. Contemporary Crit Care. 7(8), Jan 2010, 1-8 1/17/2012 44 43 Weaning Parameters Weaning parameters • No routine application of weaning parameters – Consider weaning only when evidence of clinical improvement, adequate oxygenation, stable hemodynamics, and the patient is able to breathe spontaneously with appropriate resp mechanics • Adequate Oxygenation – PaO2 >60-70 on FiO2 .4 to .5 and PEEP 58cmH20 – PaO2/FiO2 ratio >150-200 • Adequate Ventilation Epstein, SK. Contemporary Crit Care. 7(8), Jan 2010, 1-8 – PaCO2 35-45mmHg – PH 7.3 to 7.45 45 Weaning parameters • Types of weaning trials – Pressure Support/ CPAP – SIMV with Pressure Support – T-piece trial – Extubation to NIV Spontaneous Breathing Trials • Spontaneous breathing trials (whether single or multiple trials) led to extubation more quickly than those receiving Pressure Support and IMV for weaning purposes in patient who are mechanically ventilated for > 1 week Esteban, A et al. (1995, Feb 9). N Engl J Med, 332(6):345-50 . 8 1/17/2012 Weaning Parameters • Signs of distress during weaning… – Increased tachypnea (>30) – Increased heart rate – Irregular breathing pattern or use of accessory muscles – Agitation or panic unrelieved by assurance – Decrease pH to less than 7.25-7.3 with increasing PCO2 Treatment Considerations 50 Treatment Guidelines • Patients weaning from mechanical ventilation – Consider each patient’s case and determine their ability to tolerate both spontaneous breathing trials (SBTs) and rehab sessions – May be optimal to treat prior to SBT or after they are rested – Consider mobility and strengthening 1st, then weaning Treatment Guidelines • Communication and teamwork are essential for optimal treatment coordination . . . . Treatment Guidelines • Consider the need for increased FiO2 or vent support prior to mobilizing a pt in order to maximize their pulmonary status. Communicate with medical team to discuss best settings • Treatment Guidelines • Oxyhemoglobin dissociation curve – Remember that SaO2 below 90% represents large changes in PaO2 Consider reason for resp failure? – – – Failure to oxygenate? Failure to ventilate? Both? 9 1/17/2012 Ambulating a Patient on Mechanical Ventilation Ambulating a Patient on Mechanical Ventilation • Requires teamwork with the entire medical team • Most standard ventilators do not run on battery. Will likely need to use a portable ventilator or a ambu-bag to ventilate the patient while mobilizing Steps to mobilizing a patient on mechanical ventilation • ETT placement – – • Make sure tape is secure prior to moving pt!!! Look at cm mark at lip before and after treatment to assure no movement had occurred May want to talk with team if patient has an FiO2 of .60 or greater and/or if PEEP is -10cm H2O or greater to ensure medical stability Literature Highlights 57 Early Mobility in the ICU 58 Early Mobility in the ICU •Prospective study of 103 consecutive pts admitted to RICU over 6 mo period • 40% of all mobility activities were performed with an endotracheal tube in place •Criteria for inclusion for early activity: • At RICU discharge… –MV requirement >4 days –Neurologic: response to verbal stimuli –Respiratory: FIO2<0.6, PEEP<10 cm H2O –Cardiovascular: No orthostatic hypotension or pressors – 64% (23) of patients age 65 or greater ambulating more than 100ft – 74% (36) of patients less than 65 ambulating more than 100 ft •Activity goal: ambulate >100 ft before ICU d/c Bailey P et al. Crit Care Med. 2007, Vol 3(1) Bailey P et al. Crit Care Med. 2007, Vol 3(1) 10 1/17/2012 Early Mobility in the ICU • Transfer of patients to an ICU which promoted mobility resulted in almost a 3-fold increase in ambulation • This improvement in ambulation was not explained by improvements in physiology Early Mobility in the ICU • RCT with early PT and OT for mechanically ventilated adults (usual care vs. intensive PT/OT co-treatment. Both groups got daily sedation interruption) • Sessions begun with PROM if pt was unresponsive and progressed as patient tolerated to include AAROM/AROM, ADLs, and mobility Schweickert, W.D. et al. (2009, May 30. Lancet. 373(9678), 1874-1882 Thomsen SE et al. (2008). Crit Care Med. 2008. Vol 36(4): 1119-1124. Early Mobility in the ICU • Pts in intervention group had… – Shorter duration of delirium (median 2 vs 4 days) – More ventilator free days (median 23.5 vs 21.1 days) – Improved return to independent functional status (59% vs. 35%) – No difference in LOS Early Mobility in the ICU • Multi-disciplinary QI project to decrease sedation and increase PT and OT services in a medical ICU • Changes in sedation practices made from continuous infusion to a prn basis • Patients were more alert, less delirious, and had low pain scores Needham DM et al. (2010, Apr). Arch Phys Med Rehabil. 91(4):536-42 Schweickert, W.D. et al. (2009, May 30. Lancet. 373(9678), 1874-1882. Early Mobility in the ICU • Results of QI project: – Increased numbers of patients receiving PT and OT services and increased numbers of treatment sessions – Deep sedation was not necessary for patient comfort – Decreased ICU and hospital length of stay (2.1 and 3.1 days respectively) Thank you! [email protected] 1/17/2012 Needham DM et al. (2010, Apr). Arch Phys Med Rehabil. 91(4):536-42 66 11 1/17/2012 Additional References • Bailey, P.P., Miller, R.R., 3rd, & Clemmer, T.P. (2009, Oct). Culture of early mobility in mechanically ventilated patients. Crit Care Med, 37(10 Suppl):S429-35. • Clini, E & Ambrosino, N. (2005, Sep). Early physiotherapy in the respiratory intensive care unit. Respiratory Medicine, (9):1096-104. • Ciesla, N. D. (2004). Physical therapy associated with respiratory failure. In DeTurk, W.E and Cahalin, L.P (Eds.), Cardiovascular and Pulmonary Physical Therapy (pp. 541587). New York: McGraw-Hill. • Dean, E. (2008). Mobilizing patients in the ICU: Evidence and principles of practice. Acute Care Prospectives, Vol. 17(1). Additional References • Hopkins, R.O., & Spuhler, V.J. (2009, Jul-Sep). Strategies for promoting early activity in critically ill mechanically ventilated patients. ACCN Adv Crit Care, 20(3):277-289. • Irwin, S and Tecklin, JS. (2004). Cardiopulmonary Physical Therapy: A Guide to Practice, (4th ed.). St Louis: Mosby. • Perme, C., & Chandraskekar, R.K. (2008). Managing the patient on mechanical ventilation in ICU: Early mobility and walking program. Acute Care Prospectives,Vol 17(1). • Sadowsky, H.S. Monitoring and life support equipment. In E.A. Hillegass and H.S. Sadowsky, Essentials of cardiopulmonary physical therapy. (pp. 509-533). 2001; Philadelphia: Saunders. Additional References • Fessler, H.E. & Hess, D.R. (2007). Respiratory controversies in the critical care setting. Does highfrequency ventilation offer benefits over conventional ventilation in adult patients with acute respiratory distress syndrome? Respiratory Care. 2007. 52, (5), 595605. • Frownfelter, D. (1987). Chest Physical Therapy and Pulmonary Rehabilitation. (pp. 729-744). St. Louis: Mosby. • Frowley PM and Habashi, NM. Airway Pressure Release Ventilation: Theory and Practice. AACN. 2001;Vol 12(2), 234-246. Additional References • Stawicki, S.P., Goval, M., & Sarani, B. (2009, Jul-Aug). Frequency oscillatory ventilation (HFOV) and airway pressure release ventilation (APRV): a practical guide. J Intensive Care Med, 24(4):215-29. Epub 2009 Jul 17. • Tobin, MJ. (2001, June 28) Advances in mechanical ventilation. NEJM, 344(26) Yosefy, C., Hay, E., & Ben-Barak, A. (2003). BiPAP ventilation as assistance for patients presenting with respiratory distress in the department of emergency medicine. American Journal of Respiratory Medicine. 2(4), 343-7. • Zanni, J.M., & Needham, D.M. (2010, May). Promoting early mobility and rehabilitation in the intensive care unit. PT in Motion, 32-39 12