| Abstract: | 加護病房中的病童多以脈動式氧合測量器監測氧氣飽和度(SpO2)，但在臨床上有SpO2值與SaO2值相差甚遠的情形存在。因此，本研究目的探討：一、SpO2值與SaO2值是否有差異？二、SpO2值的正確性受到那些因素的影響？三、SpO2值與SaO2值相關程度為多少？四、是否能以SpO2值預測SaO2值？五、臨床上SpO2值的警戒線為何？本研究採橫斷面描述型的調查研究法。以中部某醫學中心小兒心臟加護病房的病童為可及母群體，記錄SpO2值及SaO2值，且收集記錄病童臨床病況，共收集46名個案，458筆資料。將收集的資料針對SpO2值與SaO2值進行統計分析，其結果為：本研究樣本的SpO2值與SaO2值有差異性存在，但兩者相關性高；SpO2值之正確性與病患的血球容積、膽紅素值、動脈血中的酸鹼度、動脈血中二氧化碳濃度、動脈血中氧濃度、是否靜脈注射冠狀動脈擴張劑（NTG）及是否靜脈滴注PGE1等變項間有關，而與病患的體溫、脈動式氧合測量器置放的部位、血中鈣離子濃度、血紅素濃度及是否靜脈輸注血管收縮劑等變項與SpO2值之正確性之間無關；以SpO2值能夠有效預測SaO2值，所得的迴歸方程式為：SaO2檢驗值＝－9.029＋1.085 SpO2測量值；當脈動式氧合測量器的測量值小於93﹪時，臨床工作人員需密切注意病患是否出現缺氧的徵象。由本研究可了解醫護人員在使用脈動式氧合測量器時，需對其系統之原理、使用限制和適應症有所了解，才能更有效預測病人的病況，進而促進護理品質。
Pulse oximetry is widely used as a monitoring technology in operation room, intensive care unit, and other areas. This method is noninvasive, simple to operate, and adaptable to various patient population. But, some clinical limitations of pulse oximetry had been highlighted. The aim of the study was to detect relationship between SpO2and SaO2.
This was a descriptive study. There were 46 pediatric patients with congenital heart disease (CHD), whom were studied in pediatric intensive care unit (PICU). We collected patients’ conditions, SpO2 values, and SaO2 values. Noninvasive SpO2 was determined by a pulse oximetry (N-25; Nellor Oxisensor II N-25), was compared with direct arterial blood oxygen saturation (SaO2) measured by a cooximetry (GEM-PREMIER: blood gas/ electrolyte analyzer, model 5300).
SpO2 values and SaO2 values were compared using paired t-test, a significant difference was found (t=5.984, p<0.01). Pearson correlation coefficients between pulse oximetry (SpO2) and direct blood oxygen saturation (SaO2) measurement was 0.920 (p<0.01). For SpO2 values and SaO2 values, there was significant correlation between hematocrit (Hct), bilirubin level, arterial oxygen partial pressure (PaO2), arterial carbon dioxide partial pressure (PaCO2), arterial blood of acid-base level (PH), NTG use, and PGE1 use. For SpO2 values and SaO2 values, there was no significant correlation between patient’s temperature, calcium level, position of pulse oximetry, and vasoconstrictor use. The linear regression equation for predicting SaO2 values from SpO2 values was found to be Y= -9.029 + 1.085X. Bland and Altman method was applied. The difference between the two methods (arterial oxygen saturation, determined noninvasively by pulse oximetry of SpO2, and in vitro analysis of SaO2), was -1.70%, with SpO2 values higher than SaO2 values, and limits of agreement (mean±2SD) ranged from -10.07% to 6.67%.
The ability of pulse oximetry to reliably predict change in SaO2 based on change in pulse oximetry was limited. We recommend measurement PaO2 or SaO2 for important clinical decisions. Nursing care based on knowledge of these limitations and controversial factors associated with the device will enhance the quality of clinical care. |
