Volume 85, Issue 5, Pages 656-668 (May 1984) Cardiovascular-Pulmonary Monitoring in the Intensive Care Unit (Part 2)  Herbert P. Wiedemann, M.D., Michael A Matthay, M.D., F.C.C.P, Richard A. Matthay, M.D., F.C.C.P  CHEST  Volume 85, Issue 5, Pages 656-668 (May 1984) DOI: 10.1378/chest.85.5.656 Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 13 Portable chest roentgenogram of an ICU patient showing a pulmonary infiltrate which developed distal to the tip of the Swan-Ganz catheter in the right lower lobe. The tip of the catheter is located too far peripherally. At autopsy, there was a hemorrhagic infarct of the lateral basal segment of the right lower lobe. Thrombus was found in the pulmonary artery segment immediately proximal to the infarcted area. CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 14 Upper panel, Some proposed mechanisms for pulmonary artery perforation or rupture by the Swan-Ganz. Lower panel, Design modifications that have been proposed to lessen the risk of pulmonary artery trauma. The suggestion for using a temperatureinsensitive material for the catheter shaft is pertinent to the special situation of cardiopulmonary bypass surgery. The cooled perfusate makes the catheter rigid and is perhaps one reason why cardiopulmonary bypass presents a higher risk for pulmonary artery rupture than routine ICU monitoring (see text). (Reproduced from reference 112 with permission.) CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 15 Relationship of tidal volume, air flow rates, and ventilator dial reading in a patient receiving mechanical ventilation with 10 cm H2O of PEEP. The static pressure is more apparent if expiratory retard or inspiratory hold is used, or if the expiratory tubing is momentarily occluded or pinched. Static compliance = tidal   volume static   pressure   −   PEEP In this example, static compliance equals 500 ÷ (20-10) = 50 ml/cm H2O. The normal static compliance of the lung and chest wall in a mechanically ventilated patient is about 50 to 70 ml/cm H2O. If lung and chest wall compliance is reduced (<25 ml/cm H2O), the increased work of breathing will hinder weaning. If flow is also measured (requires a pneumotachograph), then airway resistance (Raw) can be calculated: Raw= peak   pressure   −   static   pressure flow In this example (40-20) ÷ 2 = 10 cm H2O/L/second. Normal Raw is between 2 and 3 cm H2O/L/second. Increased airways resistance might be due to bronchospasm or secretions, for instance. (Reproduced from reference 146 with permission.) CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 16 Pressure-volume curves may aid in the differential diagnosis of acute respiratory distress in ventilated patients. The peak and static airway pressures (see Fig 15) are determined at various tidal volumes. The resulting dynamic characteristic curve and static compliance curve are plotted. Airway events (bronchospasm, secretions) will cause more shift of the dynamic characteristic curve than the static compliance curve. In contrast, many other lung pathologies will shift the curves about equally from the baseline. (Reproduced from reference 149 with permission.) CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 17 This is an AP portable chest roentgenogram taken on a patient receiving mechanical ventilation for acute respiratory failure secondary to Guillain-Barré syndrome. The tip of the endotracheal tube (arrow) lies in the right mainstem bronchus. The roentgenogram demonstrates atelectasis of the left lung with shift of the mediastinal structures, including the heart and the esophagus (containing air), toward the left. The first evidence of this problem was a rise in the peak airway pressure from 28 cm H2O to 50 cm H2O. Auscultation of the chest revealed decreased breath sounds on the left, and this chest roentgenogram confirmed that the endotracheal tube had slipped into the right mainstem bronchus. CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 18 Schematic for full respiratory monitoring. Airflow, pressure, and gas concentrations are continuously assessed. Calculations are made by computer utilizing this input and other data (eg, arterial blood gas values). Such a system is not yet practical for routine ICU use. (Reproduced from reference 146 with permission.) CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 19 Assessment of lung water by the thermal dye technique in four groups of ICU patients. Group 1 was a diverse group of patients without sepsis or roentgenographic pulmonary edema; group 2 consisted of patients with acute sepsis or inflammation but no roentgenographic evidence of pulmonary edema; group 3 consisted of those with heart disease and roentgenographic evidence of pulmonary edema; group 4 had radiographically defined pulmonary edema with no apparent cardiac disease. Lung water was greater in group 4 than group 3, despite a significantly lower wedge pressure (PCWP) in group 4. This presumably reflects the influence of an increase in capillary permeability in group 4. * = Significantly different from group 3; + significantly different from groups 1, 2, and 4. (Reproduced from reference 163 with permission. CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 20 Diagram of the principles underlying application of the multiple-indicator dilution technique to measurement of lung clearance properties. A bolus injection of a “reference” tracer and a “removable” tracer is given into the right atrial port of the Swan-Ganz catheter. The reference tracer (such as cardiogreen) passes through the lungs with no uptake or metabolism. The “removable” tracer (such as 5-hydroxytryptamine or 5-HT) is taken up and metabolized by the pulmonary endothelial cell. Blood is sampled at one-second intervals from the radial artery by using an external pump and fraction collector. The concentration of the tracers in each fraction is measured. At each time point, the ratio of the difference between the concentration of the reference and removable tracer (both normalized to total amount injected) to the concentration of the reference tracer provides a measure of removal. Assessment of endothelial cell function in this manner may provide a sensitive method of detecting early lung injury or subsequent repair. (Reproduced from reference 166 with permission.) CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 21 Left ventricular ejection fraction (LVEF) curves during one cardiac cycle in two different patients. The curves are generated by detection of equilibrium blood-pool radionuclide label by a miniature cadmium telluride detector module placed directly on the chest wall. There is clear delineation of end-diastole (peaks) and endsystole (valley). LVEF is determined by the difference in height of the curve at end-diastole and end-systole (in this photograph, the curves are displayed after background correction). This technology offers the possibility for noninvasive, continuous beat-to-beat monitoring of LVEF in ICU patients. (Reproduced from reference 170 with permission.) CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions

Figure 22 Sequence of changes in a patient during a 20-minute attempt to discontinue mechanical ventilation. The initial change was a fall in the ratio of high- to low-frequency power of the respiratory muscles as detected by surface electromyography. After the change in high/low ratio, there was a progressive rise in respiratory rate and an initial respiratory alkalosis. After the onset of paradoxic respiration, minute ventilation progressively decreased and hypercapnia and respiratory acidosis developed. Thus, the fall in high/low ratio may be a useful predictor of diaphragmatic fatigue that precedes clinical evidence of impending respiratory failure. (Reproduced from reference 173 with permission.) CHEST 1984 85, 656-668DOI: (10.1378/chest.85.5.656) Copyright © 1984 The American College of Chest Physicians Terms and Conditions