Alterações na Pressão Arterial durante Ventilação Mecânica. Rafael Lisboa de Souza Especialista em Medicina Intensiva pela UFSC e AMIB

Transcription

1 Alterações na Pressão Arterial durante Ventilação Mecânica Rafael Lisboa de Souza Especialista em Medicina Intensiva pela UFSC e AMIB

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5 Changes in Arterial Pressure during Mechanical Ven4la4on. Michard, Frederic Anesthesiology. 103(2): , August Fig. 2 Phasic flow tracings of vena cava blood flow, pulmonary artery blood flow, and aorrc blood flow. PosiRve- pressure inspiraron induces successively a decrease in vena cava blood flow ( 1), a decrease in pulmonary artery blood flow (2), and a decrease in aorrc blood flow (3). From Morgan et al. 31; used with permission American Society of Anesthesiologists, Inc. Published by Lippinco@ Williams & Wilkins, Inc. 3

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7 Changes in Arterial Pressure during Mechanical Ven4la4on. Michard, Frederic Anesthesiology. 103(2): , August Fig. 3 Physiologic effects of mechanical venrlaron in hypovolemic condirons. Right ventricular preload decreases because the increase in pleural pressure induces a compression of the superior vena cava ( 1) and an increase in intramural right atrial pressure (2), while the transmural right atrial pressure decreases. In West zones I (pulmonary arterial pressure 3). In West zones III (alveolar pressure 4). The increase in pleural pressure induces a decrease in lex ventricular axerload (5). LA = lex atrium; LV = lex ventricle; Palv = alveolar pressure; Ppl = pleural pressure; RA = right atrium; RV = right ventricle American Society of Anesthesiologists, Inc. Published by Lippinco@ Williams & Wilkins, Inc. 4

8 Changes in Arterial Pressure during Mechanical Ven4la4on. Michard, Frederic Anesthesiology. 103(2): , August Fig. 4 Physiologic effects of mechanical venrlaron in hypervolemic condirons. The vena cava and right atrium are poorly compliant and compressible and hence relarvely insensirve to changes in pleural pressure. West zones III (alveolar pressure 4). The increase in pleural pressure induces a decrease in lex ventricular axerload (5). LA = lex atrium; LV = lex ventricle; Palv = alveolar pressure; Ppl = pleural pressure; RA = right atrium; RV = right ventricle American Society of Anesthesiologists, Inc. Published by Lippinco@ Williams & Wilkins, Inc. 5

9 Changes in Arterial Pressure during Mechanical Ven4la4on. Michard, Frederic Anesthesiology. 103(2): , August Fig. 1 AnalyRcal descripron of respiratory changes in arterial pressure during mechanical venrlaron. The systolic pressure and the pulse pressure (systolic minus diastolic pressure) are maximum (SPmax and PPmax, respecrvely) during inspiraron and minimum (SPmin and PPmin, respecrvely) a few heartbeats later, i.e., during the expiratory period. The systolic pressure variaron (SPV) is the difference between SPmax and SPmin. The assessment of a reference systolic pressure (SPref) during an end- expiratory pause allows the discriminaron between the inspiratory increase ([DELTA]up) and the expiratory decrease ([DELTA]down) in systolic pressure. Pa = arterial pressure; Paw = airway pressure American Society of Anesthesiologists, Inc. Published by Lippinco@ Williams & Wilkins, Inc. 2

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20 Changes in Arterial Pressure during Mechanical Ven4la4on. Michard, Frederic Anesthesiology. 103(2): , August Fig. 7 Techniques available at the bedside to assess the respiratory variaron in lex ventricular stroke volume induced by mechanical venrlaron. The abdominal aorrc blood velocity variaron and the pulse oximeter signal variaron have not been validated to predict fluid responsiveness American Society of Anesthesiologists, Inc. Published by Lippinco@ Williams & Wilkins, Inc. 8

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28 Changes in Arterial Pressure during Mechanical Ven4la4on. Michard, Frederic Fig. 9 Anesthesiology. 103(2): , August Fig. 9 How to assess the respiratory variaron in arterial pressure in clinical pracrce. CO = cardiac output; [DELTA] PP = arterial pulse pressure variaron; PEEP = posirve end- expiratory pressure; SV = stroke volume; Svo2 = mixed venous oxygen saturaron; VT = Rdal volume American Society of Anesthesiologists, Inc. Published by Lippinco@ Williams & Wilkins, Inc. 11

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41 OBRIGADO!