Castro Danny, Patil Sachin M., Zubair Muhammad, Keenaghan Michael
Baylor College of Med & TX Children Hosp
University of Missouri Columbia MO
Blood gas analysis is a commonly used diagnostic tool to evaluate the partial pressures of gas in blood and acid-base content. Understanding and using blood gas analysis enables providers to interpret respiratory, circulatory, and metabolic disorders. A "blood gas analysis" can be performed on blood obtained from anywhere in the circulatory system (artery, vein, or capillary). An arterial blood gas (ABG) explicitly tests blood taken from an artery. ABG analysis assesses the patient's partial pressures of oxygen (PaO) and carbon dioxide (PaCO). PaO provides information on the oxygenation status, and PaCO offers information on the ventilation status (chronic or acute respiratory failure). PaCO is affected by hyperventilation (rapid or deep breathing), hypoventilation (slow or shallow breathing), and acid-base status. Although oxygenation and ventilation can be assessed non-invasively via pulse oximetry and end-tidal carbon dioxide monitoring, respectively, ABG analysis is the standard. When assessing the acid-base balance, most ABG analyzers measure the pH and PaCO directly. A derivative of the Hasselbach equation calculates the serum bicarbonate (HCO) and base deficit or excess. This calculation frequently results in a discrepancy from the measured value due to the blood CO unaccounted for by the equation. The measured HCO uses a strong alkali that liberates all CO in serum, including dissolved CO, carbamino compounds, and carbonic acid. The calculation only accounts for dissolved CO; this measurement uses a standard chemistry analysis and will likely be called a "total CO". Therefore, the difference will amount to around 1.2 mmol/L. However, a more considerable difference may be seen in the ABG compared to the measured value, especially in critically ill patients. The calculation has been disputed as both accurate and inaccurate based on the study, machine, or calibration used and must be interpreted appropriately based on institutional standards. Emergency medicine, intensivist, anesthesiology, and pulmonology clinicians frequently order arterial blood gases, which may also be used in other clinical settings. Healthcare professionals evaluate many diseases using an ABG, including acute respiratory distress syndrome (ARDS), severe sepsis, septic shock, hypovolemic shock, diabetic ketoacidosis, renal tubular acidosis, acute respiratory failure, heart failure, cardiac arrest, asthma, and inborn errors of metabolism.
血气分析是一种常用的诊断工具，用于评估血液中气体的分压和酸碱含量。理解并运用血气分析能使医疗人员解读呼吸、循环和代谢紊乱情况。“血气分析”可对从循环系统任何部位（动脉、静脉或毛细血管）获取的血液进行检测。动脉血气（ABG）明确检测从动脉采集的血液。ABG分析评估患者的氧分压（PaO）和二氧化碳分压（PaCO）。PaO提供有关氧合状态的信息，PaCO提供有关通气状态（慢性或急性呼吸衰竭）的信息。PaCO受过度通气（快速或深呼吸）、通气不足（缓慢或浅呼吸）以及酸碱状态影响。尽管可分别通过脉搏血氧饱和度测定法和呼气末二氧化碳监测进行无创性的氧合和通气评估，但ABG分析仍是标准方法。在评估酸碱平衡时，大多数ABG分析仪直接测量pH值和PaCO。通过Hasselbach方程的一个衍生公式计算血清碳酸氢盐（HCO）以及碱缺失或碱过剩。由于该方程未考虑血液中的CO，此计算结果常常与测量值存在差异。测量的HCO使用强碱来释放血清中所有的CO，包括溶解的CO、氨基甲酸盐化合物和碳酸。该计算仅考虑溶解的CO；此测量采用标准化学分析，可能会被称为“总CO”。因此，差异约为1.2 mmol/L。然而，与测量值相比，ABG中可能会出现更大的差异，尤其是在危重症患者中。根据所使用的研究、仪器或校准情况，该计算的准确性一直存在争议，必须根据机构标准进行恰当解读。急诊医学、重症医学、麻醉学和肺病学的临床医生经常开具动脉血气检查单，其也可用于其他临床场景。医疗专业人员使用ABG评估多种疾病，包括急性呼吸窘迫综合征（ARDS）、严重脓毒症、脓毒性休克、低血容量性休克、糖尿病酮症酸中毒、肾小管酸中毒、急性呼吸衰竭、心力衰竭、心脏骤停、哮喘以及先天性代谢缺陷。
