ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

One hundred and six critically ill adult patients were monitored continuously with a transcutaneous oxygen sensor (PtcO2); they also were intermittently monitored with conventional invasive hemodynamic and oxygen transport variables. A total of 1073 data sets were taken on 41 patients in the ICU and 65 patients in the operating room. The patients were divided into three groups by cardiac index (CI): relatively normal flow, CI > 2.2 L/ min μ M2; moderate low flow shock, 2.2 > CI > 1.5 L/ min μ M2; and severe low flow shock, CI < 1.5 L/min μ M2. PtcO2and arterial oxygen tension (Pao2) were compared in two ways; first by linear regression and second by a more simple clinical guide by indexing each transcutaneous value by its respective arterial value (Ptco2index = Ptco2/Pao2). For 934 data sets taken on 92 patients not in shock, there was a correlation coefficient (r) of 0.89 and a Ptco2index 0.79 ± 0.12 (SD). In 5 patients with moderate shock, the r was 0.78 and the Ptco2index was 0.48 ± 0.07. In 9 patients with severe shock, there was no correlation between Ptco2and Pao2and the Ptco2index was 0.12 ± 0.12. In all cases of severe shock, the Ptco2value responded quickly to changes in blood flow with an approximate 1 min response time (95%). The patients not in shock responded to changes in inspired oxygen concentration (FIO2) with changes in Pao2and PtcO2values; the 95% response time was approximately 2 min. The authors conclude that the normal value for PtcO2for adult surgical patients who are hemodynamically stable is 79 ± 12% of the PaO2and that PtcO2values were reliable, continuous, noninvasive trend monitors of PaO2in these patients. During circulatory problems when PtcO2values were compared to PaO2values (PtcO2index), the changes reflected trends in the severity of low flow shock.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

The value of continuous transcutaneous oxygen (PtcO2) monitoring in the presence of halothane and nitrous oxide (N2O) was studied in 10 infants. All infants were continuously monitored during the study with a Clark-type skin electrode with Mylar membrane. The polarization voltage of the membrane was changed to 600 mV to make it insensitive to N2O and halothane. The accuracy of PtcO2electrode was compared with simultaneously measured PaO2at different intervals. Correlation of PaO2with PtcO2was sought during hypoxic-normoxic state (PaO2between 27–92 torr) and hyperoxic state (PaO2between 105–439 torr). During hypoxic-normoxic state, the correlation between PaO2and PtcO2values was 0.94. During the hyperoxic state, poor correlation existed between PaO2and PtcO2(r = 0.51). Although PtcO2did not correlate with PaO2during hyperoxia, it consistently overestimated PaO2and thereby, provided a predictive ability by over-diagnosing hyperoxia. When combined with continuous monitoring of inspired oxygen tension to maintain normoxia, continuous monitoring of PtcO2will reduce the frequency of PaO2analysis and improve patient care during anesthesia.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID

摘要:

Several variables may account for the response of electrochemical skin surface PO2sensors to anesthetic gases: cathode material and size, pH of the electrolyte and membrane material. These variables cannot be chosen arbitrarily and their influence has been tested with two types of sensors. In one type (LSC), a large size cathode (mm range) and a membrane with low permeability for oxygen such as mono-axially oriented polyethylene is used. The other type (MC) contains one or more microcathodes (μ range) and a membrane which is highly permeable for oxygen, such as Teflon PTFE.With the LSC sensor, the N2O interference current is smaller than 5% of the air current when the sensor is polarized at –600 mV. The interference current with 2% halothane is smaller than 3% of the air current. With the MC sensor, the N2O interference may be up to 40% of the current in air when the sensor is polarized at –800 mV. The magnitude of this interference depends considerably on the silver deposition on the platinum cathode. At –600 mV the N2O interference is negligible. However, at this polarization voltage, the sensor is not operated within the limiting current plateau of oxygen. The interference current with 2% halothane may be up to 30% of the current in air. With both types of sensors there was no measurable interference by 2% enflurane. The authors conclude that to reduce the interference of anesthetic gases at skin surface sensors for oxygen to a reasonable level, it is necessary to use a membrane with low permeability for oxygen and a polarization voltage of approximately –600 mV. These two conditions can be fulfilled optimally only with a sensor design in which a large size cathode is used.At Stowe-Severinghaus type skin surface sensors for PCO2, there is no measurable interference by N2O, halothane or enflurane.

ISSN:0090-3493    

出版商:OVID    

年代:1981

数据来源: OVID