Monitoring during mechanical ventilation

摘要: SUMMARY Monitoring is the continuous, or nearly evaluation of physiologic function a patient in real time to guide diagnosis and management decisions - including when make therapeutic interventions assessment those interventions. Many parameters can be monitored during mechanical ventilation, pulse oximetry, capnography, ventilator graphics. Although its impact on outcomes has not been well studied, monitoring become an integral part care mechanically ventilated patients. Continuous oximetry standard for critically ill Two wavelengths light (660 nm 940 nm) are passed through pulsating vascular bed using two light-emitting diodes photodetector. This translated into plethysmographic waveform ratio amplitudes these waveforms display oxygen saturation. A number limitations should recognized, appreciated, understood by everyone who uses data. Most oximeter errors explained as too little signal (e.g., low perfusion, improper probe placement) much noise motion, ambient light). The newest generation oximeters affected less potential errors. At saturations >80%, accuracy about 4–5%. Below 80%, worse, but clinical importance this questionable. New also measure carboxyhemoglobin methemoglobin addition Capnometry measurement CO2 at airway opening ventilatory cycle. relationship between PaCO2 end-tidal PCO2 will vary depending upon relative contributions various V/Q units lungs. Thus, caution exercised extrapolating PaCO2. End-tidal determine proper endotracheal tube position (no exhaled with esophageal placement). slope capnogram increased patients obstruction. Volume-based capnography used assess carbon dioxide production (metabolic rate) dead space ventilation. Using volume-based it possible nonnvasively cardiac output partial rebreathing technique. Pulmonary mechanics expression lung func