The Sensitivity And Accuracy Of Transesophageal Oxygen Saturation Monitoring

Part OneA Clinical Study of Continuous Earlobe SeO₂ Monitoring by Reflecting ModeObjective Use of the pulse oximeter is standard in anaesthesia, intensive care, surgery, emergency medicine and general ward care. The goal of arterial oximetry monitoring is to ensure adequate organ blood flow and oxygen supply. Th ordinarily mode of pulse oximetry when probes are applied to peripheral parts of the body are transmission by emitter to sensor. However, it may be compromised in certain clinical situations, such as those who suffered burns or injury of locus. And clinical signs of organ perfusion have limited value in estimation of tissue perfusion. Therefore we investigate the method of transearlobe arterial oxygen saturation(SeO₂) measurements by reflecting mode. To compare oximetric readings from the earbal SeO₂ and the skin(finger) SpO₂. Methods 30 children were involved after coming into postanesthesia care unit(PACU) . A kind of one-off pediatric pulse oximetry probe (Nellcor D20 II ) was sticked on the suface of earlobe for SeO₂, which the emitter and sensor were side by side in the trial group. Another similar one was located around the end of oneself finger in the control group for SpO₂. SeO₂, SpO₂, heart rate andpulse were observed continuously and recorded per 5min simultaneously. The results of basic, 5min,10min, 20 min, 30 min, 60 min were contrasted with SeO2 and SpO2.Results l.In this syudy, 225 signs of SeO2 and SpO2 were collected synchronously. The most of readings were equal to SeC>2 and SpC>2, which was 89.8%(202/225). SeO2 was 98.0±1.4% in this course. And SpO2 was 98.4 + 1.8%. A few signs were difference, which were -1% 3%(1.4± 1.1%). Their changes of SpC>2 and SeO2were no significance^ >0.05).And the statistical Kappa was O.S3(Kappa > 0.75).Conclusion The investigation indicates that SeC>2 is credible. It also is feasible and simple that transearlobe arterial oxygen saturation continuously monitoring easurements by reflecting mode.This outcome also shows that the arterial oxygen saturation may be obtained by reflexing mode, witch close to come from arterial tissues, such as oesophagus.Part twoTransesophageal Arterial Oxygen Saturation Monitoring: An Experimental StudyObjective Use of the pulse oximeter of surface is convenience and popularization. However, the reliability of pulse oximetry when probes are applied to peripheral parts of the body may be compromised in certain patients, such as those who become hypovolaemic or have decresed cardiac output, and suffered injury of locus, peripheral vasoconstriction. Thus, SpC>2 readings are often unobtainable in situations where they would be most valuable. Arterial blood samples (SaO2) is a gold standard , but more invasive monitoring and no successive. Less invasive techniques are also constantly sought. Transoesophageal echocardiography (TEE) is a valuable monitor in anaesthetized patients and in intensive care settings, but it requires a trained operator and is time-consuming. We hypothesized that oximetry singals could be acquired from the inferior esophagus closing to descending aorta. Therefore,we investigate the method of transesophageal arterial oxygen saturation(SteO2) measurement. To assess the sensitivity and accuracy of from the esophagus and the surface of lingual mucosa oximetry (SmO2) with thoseobtained from arterial blood samples (SaO2).Methods Nine dogs were involved in this study. A disposable oximetry probe was gluded at the tip of a gastrointestinal tube, which was made by ourselves. Immediately after the induction of anesthesia , the probe was placed in the lower segment of esophagus to monitor SteC>2, a Nellor digital sensor was also pasted on the surface of lingual mucous membrane to monitor SmO2 ,and a femoral artery cannulated and SaC>2 was measured. When the signals and readings of SteC>2 and SmO2 were stable, arterial blood sample was taken and SaC>2 was measured. Then the FiC>2 was reduced and the changes of SteO2 and SmO2 were recorded until SteO2 reached to 60%, a few blood samples were taken for SaO2 measurements during this period of time. Then ventilator was re-connected with pure oxygen and the recovery rates of SteC>2 and SmCh were observed. The levels of agreement between Sted and SaC>2, SmCh and SaO2were calculated using the between-mathod differerces analysis outlined by Bland & Altman. Results1. SteC>2 readings were better and successive. Before hypoxia there was no difference in ability of the sensors to obtain readings and no difference in the accuracy of those readings. There were no significant differences in MAP, HR, ECQPetCO2andT.2. The readings of SteC>2 were precedence than SmO2 under hypoxiaoccurrenc or reversion. During hypoxia especially after nearly minuts, the SteC>2 sensor gave readings earlier and at a lower oximetry. When SteC>2 and SmO2 descend from 100% to 95%, time were recorded 201.1 ± 30.2s and 290.8 +40.7s respectively. Anoxic response with SteO2 was significantly higher than SmO2 (P < 0.05), which time was early about 90s with SteCh to SmO2.3. The deviation of SteC>2 and SmO2 from SaO2- Calculation their relative and absolute deviations by E I PrP2 I /N and I Pj-P2 I /P2/N between SteO2 and SmO2 from arterial blood samples SaC>2 . The results were 1.6% and 1.2% (SteO2 from SaO2), 7.6% and 6.1% (SmO2 from SaO2 ) respectively. SaO2 was better related with SteO2 and SmO2(R2: 0.9884 and 0.8462) respectively.4. After re-ventilation of pure oxygen, the startup was earlier with SteC>2 to SmO2. Time was early about 25s for SteCh, it was significantly than SmO2 (P < 0.05).5.Bland & Altman plot for the difference between SteO2 and SaC>2 values against their mean. Bias (mean difference ) and limits of agreement (mean difference ±2 SD) for two methods were 0.3 + 4.0%. 95% confidence interval of the difference was -1.7% to 2.3%. And SmC^and SaC>2 values against their mean. Bias (mean difference ) and limits of agreement (mean difference ± 2SD) for two methods were 3.0 + 3.9%. 95% confidence interval of thedifference was 1.4% to 4.5%.Conclusion1. This study shows that SteC>2 monitoring is sensitive. It could accurately reflet the arterial oxygen saturation not only in the normal condition but also hypoxia SteC>2 responds faster and is closer to SaC>2 than SmO2 measurements.2. The result indicates that SteC>2 monitoring can be an alternative way of oxygen satuation monitoring. It also directs that SteO2 information may be obtained early if the technic takes patients.Part ThreeTransesophageal Arterial Oxygen Saturation monitoring: A Clinical Study (Section A)Objective Pulse oxygen saturation monitoring is an one of essential measurement for the patients. The reliability of pulse oximetry depends on the the tissue perfusion. The responses of oxygen saturation and dis-saturation are some delayed when the extremeties are used for pulse oximetry. Under some clinical circumstances, the peripheral tissue perfusion may be very poor which makes the pulse oxygen satuation mornitoring unreliable or impossible. Some patients are not able to provide figures for monitoring. In the past research, we had fund that oximetry singals may be acquired from the lower segment esophagus which closes to the descending aorta. This study examined it's clinical accuracy and sensitivity as a new monitoring site for descending aortic oximetry(SteO2), and compares it's reponses with the oximetry from the figures(SpO2) and arterial blood sample(SaC>2) under normal condition and hypoxia.Method A total of 45 surgical patients undergoing general anesthesia were included in this study. The patients' age was averaged at 40.9 ± 16.2 yrs(rang: 14 to 79 yrs) with 36 men and 9 women. They were ASA I-III and without a history of esophageal desease and trauma. Immediately after the induction of anesthesia , the disposable oximetry probe which was made by ourselves was placed in the lower segment of esophagus to monitor transesophgeal oxygen satuation (SteC^), a Nellor digital sensor was also attached to the forefinger to monitor SpO2 at the same time, and a radial artery cannulated and SaO2 was measured . When the signals and readings of SteC>2 and SpO2 were stable, arterial blood sample was taken and SaC>2 was measured. Then the ventilator was disconnected and the changes of SteC>2 and SpC>2 were recorded until SteO2 reached to 90%, a few blood samples were taken for SaC>2 measurements during this period of time. Then ventilator was re-connected and the recovery rates of SteCh and SpC>2 were observed. The levels of agreement between SteC>2 and SaC>2, SpO2 and SaC>2 were calculated using the between-method difference analysis outlined by Bland & Altaian. Results 1. SteO2, SpO2 and SaC>2 were 100% when the patients ventilated with 100% oxygen. When the ventilator disconnected, SteO2 dropped much earlier than SpC>2 It went down faster which took 286.1 ± 15.3s for SteO2 to drop from 100% to 95% while SpO2 took 397.5 + 27.7s from 100% to 90%. It also went down faster which took 323.6 ± 20.5 s for SeO2 to drop from 100% to 90% while SpO2took 418.3 + 21.3s from 100% to 90%. SteO2 values were much closer to SaC>2 than SpC>2 during this period of time. Thetime was shorted about 110s as SteO2 values to drop from 100% to 95% or 90% than SpO2 during hypoxia (P < 0.001).2. When SteO2 took from 100% to 90%, the relative deviation of SteO2 (E I Pi-P2 I /N) , which compared with the "gold standand " SaO2 , was 6.8% and the absolute deviation of SteO2 ( I P1-P2 I /P2/N ) was 1.5%. The relative deviation of SpC>2 was 11.3% and the absolute deviation of SpC>2 was 3.1%. While SpO2 took from 100% to 90% the relative deviation of SteO2 , which compared with the "gold standand " SaCh, was 5.3% and the absolute deviation of SteC>2 was 5.0%.The relative deviation of SpC>2 was 7.6% and the absolute deviation of SpO2 was 6.0%.3. Bland & Altman plot for the difference between SteO2 and SaO2 values against their mean. Bias (mean difference ) and limits of agreement (mean difference ±2 SD) for two methods were 0.3 ± 4.3%. 95% confidence interval of the difference was -0.3% to 0.7%. And SpO2 and SaO2 values against their mean. Bias and limits of agreement (mean difference ±2 SD) for two methods were 6.8 + 5.6%. 95% confidence interval of the difference was 6.2% to 7.4%.4. When the ventilatior was re-connected, the response of SteO2 was much faster than SpO2 . hi two hemorrhagic shock patients, the SpO2 failed to show the values for at least 30 min of 2h. While the esophageal SteO2 readings remained the same as SaO2.Conclution Our study shows that tranesophageal SteO2 monitoring is sensitive and feasible in clinic. It reflexes the arterial oxygen saturation accurately under normal condition, during hypoxia or the recovery of hypoxia. It responds faster and closer to SaO2 than SpO2 measurements. The results indicate that SteO2 monitoring may be an alternative way of oxygen satuation monitoring for the patients during anesthesia, in intensive care unit and in emergency deparment.Part ThreeTransesophageal Arterial Oxygen Saturation Monitoring: A Clinical Study (Section B)This study examined SteCb clinical practicality. To compare their responses with SteO2 or SpO2 from 100% dropped to 95% under hypoxia. Than the ventilator was re-connected with 100% oxygen until SteC>2 or SpCh from the lowerst to get-back to 100%.Method A total of 20 surgical patients undergoing general anesthesia were included in this study. ASA I-III and without a history of esophageal disease and trauma. Immediately after the induction of anesthesia , the one-off oximetry probe, which was made by ourselves was placed in the lower segment of esophagus to monitor transesophgeal oxygen satuation (SteCy, a Nellor digital sensor was also attached to the forefinger to monitor SpO2 at the same time, and a radial artery cannulated and SaC>2 was measured . When the signals and readings of SteC>2 and SpC>2 were stable, arterial blood sample was taken and SaC>2 was measured. Then the ventilator was disconnected and the changes of SteC>2 and SpC>2 were recorded until leave each other of SteO2 and SpC^ reached to 95%, a few blood samples were taken for SaC>2 measurementsduring this period of time. Then ventilator was re-connected and the recovery rates of SteO2 and SpO2 were observed. The levels of agreement between SteO2 and SaO2, SpO2 and SaO2 were calculated using the between-method difference analysis outlined by Bland & Altman. Results1. SteO2, SpO2and SaO2 were 100% when the patients ventilated with 100% oxygen. When the ventilator disconnected, SteO2 dropped much earlier than SpO2. SpO2 was higher levele which took 99.5 + 0.8% for SteO2 to drop from 100% to 95%, while SaO2 took 93.6 + 1.6% at the same time. The ventilator was re-connected and oximetry failed to lower line continuously and came back later. The lowest figures of SteO2 and SaCh were 93.1%± 1.6% and 92.9 + 2.9%, While SpO2 was 98.5% +1.8%. There was no sigm'ficance(P>0.05) between SteO2 and SaO2, but there was difference between SpO2 and SaO2 (P<0.05).2. SteO2 went down faster which took 87.6 + 4.0% for SpO2 to drop from 100% to 95% while SaO2 took 87.9 + 4.3% simultaneitily. The ventilator was re-connected and oximetry also dropped to lower plane continuously and get back later. The lowest readings of SteO2 and SaO2 were 83.0% + 4.3% and 85.6±2.4%. But The lowest figures of SpO2 was 92.0%±2.3%. There was no significance(P>0.05) between SteO2 and SaO2, but there was difference between SpO2 and SaO2 (P <0.05).3. Bland & Altman plot for the difference between SteO2 and SaO2 values against their mean. Bias (mean difference ) and limits of agreement (mean difference ±2 SD) for two methods were -1.6% to 1.8% respectively. 95% confidence interval of the difference was -0.7% to 0.9%. And SpO2 and SaO2 values against their mean. Bias (mean difference ) and limits of agreement (mean difference + 2 SD) for two methods were -1.5% to 15.7% respectively. 95% confidence interval of the difference was 4.7% to 9.4%.Conclution 1. This indicates that the changes of tranesophageal SteO2 monitoring is early than SpO2 during hypoxia. It responds faster and closer to SaO2 than SpO2 measurements. So SteO2 is an important index and partially may be substitute to some invasive measurements for emergency cases.2. The information of SpO2 may be not singleness from arterial signs. But it may be mixed by tissue oxygenation.Part FourPatent of Arterial Oxygen Saturation Detection EquipmentThis is a kind of detection equipment to detect arterial oxygen saturation of aorta thoracica, which is comprised of a light emitter, a light receptor, a carrier and a connector to electrocardiogram monitor. The carrier can be a electric conductor or a non-electric conductor which is made of medical giant molecule material. If a electric conductor is used as the carrier, the light emitter and receptor can be fixed in the part of the carrier which enters human esophagus. The light emitter and receptor are fixed in the same side of the carrier. The connecter is linked to the other end of the carrier which is exposed. The receptor is linked to the connector through the carrier. If the carrier is made of medical giant molecule material, another electric conductor(a connecting lead) is required. The light emitter, receptor and connecting lead are fixed in the same side of the carrier. The exposed end of the connecting lead is linked to the connector. The receptor is linked to the connector through the connecting lead. This detection equipment is characterized of detecting body central arterial oxygen saturation accurately and indicating the oxygenation and the oxygensupply of important organs promptly.