Ngón tay, tai, da truyền thăm dò các biện pháp hoặc phản xạ của ánh sáng đỏ và hồng ngoại thông qua hấp thụ mô đụng kêu ("đánh bại-to-beat") xác định tỷ lệ phần trăm của oxyhemoglobin Oxyhemoglobin máu, carboxyhemoglobin, methemoglobin đọc là "oxyhemoglobin" đụng kêu dạng sóng cần thiết tính, tưới máu thấp | 20 Current Essentials of Critical Care Pulse Oximetry Essential Concepts Finger ear or other cutaneous probe measures transmission or reflectance of red and infrared light through tissue Pulsatile absorbance beat-to-beat determines percentage of oxyhemoglobin in blood Oxyhemoglobin carboxyhemoglobin and methemoglobin read as oxyhemoglobin Pulsatile waveform essential for calculation low perfusion hypotension arterial disease motion artifacts interfere with measurement Correlates well with arterial blood O2 saturation Essentials of Management Use for routine monitoring of patients in ICU and during endoscopy bronchoscopy minor surgery suctioning sleep apnea episodes bronchodilator therapy Use to adjust supplemental oxygen therapy including mechanical ventilation Provides estimate of arterial oxygenation still need arterial blood gases for PaCO2 and pH. Do not use to exclude significant carboxyhemoglobinemia eg after smoke inhalation May not be accurate during cardiopulmonary resuscitation Attach to ear lobe or finger according to manufacturer s instructions Check for pulsatile waveform on monitor if provided If waveform is poor or pulse oximeter does not provide an adequate reading try other locations Pearl Very high methemoglobin levels have the peculiar effect of causing the pulse oximeter to read 75 regardless of concentration or oxygenation. Reference Lee WW et al The accuracy of pulse oximetry in the emergency department. Am J Emerg Med 2000 18 427. PMID 10919532 Chapter 1 Monitoring Support 21 Upper GI Bleeding Prevention Essential Concepts 10-25 incidence of shallow stress-induced ulceration of gastric mucosa with subclinical or clinically important upper GI bleeding in critically ill patients associated with poor outcome increased mortality May have clinical bleeding or persistent unexplained fall in hemoglobin Risk factors mechanical ventilation coagulopathy thrombocytopenia renal failure burns postsurgical possibly lack of enteral feeding aspirin may be .
