RT Book, Section A1 Butterworth IV, John F. A1 Mackey, David C. A1 Wasnick, John D. SR Print(0) ID 1161434332 T1 Inhalation Therapy & Mechanical Ventilation in the PACU & ICU T2 Morgan & Mikhail's Clinical Anesthesiology, 6e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259834424 LK accessmedicine.mhmedical.com/content.aspx?aid=1161434332 RD 2024/03/28 AB KEY CONCEPTS Hyperoxia and hypoxia are risk factors for but not the primary causes of retinopathy of prematurity (ROP). Neonates’ risk of ROP increases with low birth weight and complexity of comorbidities (eg, sepsis). The disadvantage of conventional PCV is that tidal volume (VT) is not guaranteed (although there are modes in which the consistent delivered pressure of PCV can be combined with a predefined volume delivery). Pressure control ventilation (PCV) is similar to pressure support ventilation in that peak airway pressure is controlled but is different in that a mandatory rate and inspiratory time are selected. As with pressure support, gas flow ceases when the pressure level is reached; however, the ventilator does not cycle to expiration until the preset inspiration time has elapsed. Both nasotracheal and orotracheal intubation appear to be relatively safe for at least 2 to 3 weeks. When left in place for more than 2 to 3 weeks, both orotracheal and nasotracheal tubes predispose patients to subglottic stenosis. If longer periods of mechanical ventilation are necessary, the tracheal tube should generally be replaced by a cuffed tracheostomy tube. The major effect of positive end-expiratory pressure (PEEP) on the lungs is to increase functional residual capacity (FRC). In patients with decreased lung volume, appropriate levels of either PEEP or continuous positive airway pressure (CPAP) will increase FRC and tidal ventilation above closing capacity. This will improve lung compliance and will correct ventilation/perfusion abnormalities. Compared with a VT of 12 mL/kg, a VT of 6 mL/kg and plateau pressure (Pplt) less than 30 cm H2O have been associated with reduced mortality in patients with acute respiratory distress syndrome. A higher incidence of pulmonary barotrauma is observed with excessive PEEP or CPAP at levels greater than 20 cm H2O. Maneuvers that produce sustained maximum lung inflation, such as the use of an incentive spirometer, can be helpful in inducing cough as well as preventing atelectasis and preserving normal lung volume.