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At least 19 recordsLinked to original sources

PubMed1991

[Intra-arterial catheter oximetry and pulse oximetry in comparison with CO-oximetry in heart surgery].

This study evaluates the measurement of oxygen saturation by arterial catheter oximetry and pulse oximetry. The values are compared to values obtained by CO-oximetry. METHODS. In eight patients undergoing cardiac surgery, we determined the oxygen saturation of arterial and mixed-venous blood by CO-oximetry (IL 282, Instrumentation Lab) at prospectively defined points of measurement before, during, and after extracorporeal circulation. At the same points of measurement, saturation readings obtained by arterial catheter oximetry (U425C, Abbott) and pulse oximetry (Siemens/Nellcor) were recorded. RESULTS. The mean saturation values determined by both catheter oximetry and pulse oximetry differed from the mean values obtained by CO-oximetry by less than 1% (= bias). The standard deviations of the readings in relation to readings of CO-oximetry (= precision) were +/- 0.5% to +/- 1.0% for catheter oximetry and +/- 1.0% to +/- 1.3% for pulse oximetry. Furthermore, it was possible to obtain saturation readings in 99%-100% of measurements by catheter oximetry; in contrast, this was possible by pulse oximetry in only 59%-84% of measurements. Low mixed-venous saturation values were not indicated by any of the arterial methods of measurement. CONCLUSIONS. Catheter oximetry was superior to pulse oximetry with regard to both precision of saturation values and reliability to obtain values. Invasiveness and high costs are disadvantages of catheter oximetry, but if reliable and exact measurements are important at any time during surgery or intensive therapy, intra-arterial catheter oximetry is preferable to pulse oximetry.

Cardiac Surgical Procedures↗

PubMed1992

Continuous intra-arterial oximetry, pulse oximetry, and co-oximetry during cardiac surgery.

This study evaluated arterial catheter oximetry versus pulse oximetry in eight patients (ASA III-IV) who underwent cardiac surgery. Co-oximeter saturation values served as the standard. Arterial oxygen saturation was determined simultaneously with these three methods at 162 prospectively defined points of measurement before, during, and after cardiopulmonary bypass (CPB). At the same times before and after CPB, arterial, pulmonary arterial, and central venous pressures, and cardiac output determinations were recorded. Saturation readings were obtained in more than 99% of measurements with catheter oximetry and in only 59% to 84% of measurements with pulse oximetry. Failure of pulse oximetry correlated with low mean arterial pressures and low cardiac outputs, but not with high systemic vascular resistance. The mean saturation values determined by catheter oximetry as well as by pulse oximetry differed from the mean values obtained by co-oximetry by less than 1% (= bias). The standard deviations of the individual differences between readings of catheter or pulse oximetry and readings of co-oximetry (= precision) were +/- 0.5% to +/- 1.0% for catheter oximetry and +/- 1.0% to +/- 1.2% for pulse oximetry. In summary, catheter oximetry was superior to pulse oximetry with regard to obtaining readings and to reliability of the obtained readings. Invasiveness and high costs influence the decision as to whether to use catheter oximetry, but if reliable and precise measurements of saturation are important at any time during surgery, pulse oximetry is an insufficient method and co-oximetry is a time-consuming method of analysis, whereas catheter oximetry is quick, reliable, and precise.

Adult↗

PubMed1997

Multicenter study on the clinical value of fetal pulse oximetry. II. Compared predictive values of pulse oximetry and fetal blood analysis. The French Study Group on Fetal Pulse Oximetry.

OBJECTIVE: Our purpose was to compare the predictive value of intrapartum fetal pulse oximetry with that of fetal blood analysis for an abnormal neonatal outcome in case of an abnormal fetal heart rate. STUDY DESIGN: A prospective multicenter observational study was conducted from June 1994 to November 1995. Fetal oxygen saturation was continuously recorded with a Nellcor N-400 fetal pulse oximeter in case of an abnormal fetal heart rate during labor. Simultaneous readings of fetal oxygen saturation and fetal blood analysis obtained before birth (i.e., either at full dilatation or before cesarean section when indicated) were compared with the neonatal status. The criteria for an abnormal neonatal outcome were (1) an umbilical arterial blood pH < or = 7.15 and (2) a combined variable including 5-minute Apgar score < or = 7, umbilical arterial pH < or = 7.15, secondary respiratory distress, transfer in a neonatal care unit, or neonatal death. RESULTS: At a 7.20 threshold for fetal scalp pH and 30% for fetal oxygen saturation (i.e., the 10th percentile in the study population), the predictive value of fetal pulse oximetry was similar to that of fetal blood analysis for an arterial umbilical pH < or = 7.15 and for an abnormal neonatal outcome (positive predictive value 56% vs 55%, negative predictive value 81% vs 82%, sensitivity 29% vs 35%, and specificity 93% vs 91%, respectively). The receiver-operator characteristic curve showed similar performance of either technique for cutoff values < or = 7.20 for fetal blood pH and < or = 30% for fetal oxygen saturation, whereas fetal pulse oximetry became superior at higher thresholds. CONCLUSION: The predictive value of intrapartum fetal pulse oximetry can be favorably compared with that of fetal blood analysis. Randomized controlled management trials can now be performed to assess potential clinical benefits of this new tool.

Apgar Score↗

PubMed2001

Pulse oximetry for perioperative monitoring.

BACKGROUND: Monitoring with pulse oximetry might improve patient outcome by enabling an early diagnosis and consequently, correction of perioperative events that might cause postoperative complications or even death. Only a few randomised clinical trials of pulse oximetry have been performed during anaesthesia and in the recovery room which describe perioperative hypoxaemic events, postoperative cardiopulmonary complications and cognitive dysfunction. OBJECTIVES: To study the effect of perioperative monitoring with pulse oximetry to clearly identify the adverse outcomes that might be prevented or improved by the use of pulse oximetry. SEARCH STRATEGY: Trials were identified by computerised searches of the Cochrane Library, MEDLINE, EMBASE, and by checking the reference lists of trials and review articles. SELECTION CRITERIA: All controlled trials that randomised patients to either pulse oximetry or no pulse oximetry during the perioperative period, including the operating and recovery room. DATA COLLECTION AND ANALYSIS: We collected data in relation to events detectable by pulse oximetry, any serious complications that occurred during anaesthesia or in the postoperative period, intra- or postoperative mortality, and duration of recovery or intensive care stay. Formal statistical synthesis of individual trials was not performed in view of the variety of outcomes studied. MAIN RESULTS: Searching identified six reports; four studies with data from a total of 21,773 patients were considered eligible for analysis. Only two studies specifically addressed the outcomes in question; both found no effect on the rate of postoperative complications using perioperative pulse oximetry. Two studies used hypoxaemia detectable by pulse oximetry to assess the value of perioperative monitoring, although outcomes were not given. It was found that hypoxaemia was reduced in the pulse oximetry group both in the operating theatre and in the recovery room. During observation in the recovery room, the incidence of hypoxaemia in the pulse oximetry group was 1.5-3 times less. The postoperative cognitive function using the Wechsler memory scale and continuous reaction time was independent of perioperative monitoring with pulse oximetry. The other study showed that postoperative complications occurred in 10% of the patients in the oximetry group and in 9.4% in the control group. The two groups did not differ in cardiovascular, respiratory, neurologic, or infectious complications. The duration of hospital stay was a median of 5 days in both groups, and an equal number of in-hospital deaths was registered in the two groups. REVIEWER'S CONCLUSIONS: The studies confirmed that pulse oximetry can detect hypoxaemia and related events. However, we have found no evidence that pulse oximetry affects the outcome of anaesthesia. The conflicting subjective and objective results of the studies, despite an intense, methodical collection of data from a relatively large population, indicates that the value of perioperative monitoring with pulse oximetry is questionable in relation to improved reliable outcomes, effectiveness and efficiency.

Humans↗

PubMed2001

Ear oximetry: a noninvasive method for detection of patent foramen ovale: a study comparing dye dilution method and oximetry with contrast transesophageal echocardiography.

BACKGROUND AND PURPOSE: Patent foramen ovale (PFO) may play an important role as a risk factor for ischemic stroke and some other neurological conditions. There is a need for low-cost and noninvasive methods for the detection of PFO. This study evaluates the accuracy of two simple bedside tests, the dye dilution method and ear oximetry, in the detection of PFO. METHODS: Dye dilution curves and ear oximetry recordings with a noninvasive ear densitometer were obtained from consecutive cryptogenic stroke patients referred for contrast transesophageal echocardiography (TEE). All test results were blindly assessed for the presence of PFO. Sensitivity and specificity were calculated with TEE used as a reference method. kappa statistics were used to measure interrater agreement. RESULTS: Dye dilution curves were obtained from 67 patients. Dye dilution correctly diagnosed 35 of the 46 patients who had PFO in TEE and all the 21 patients without PFO. Thus, the sensitivity (95% CI) of the dye dilution method was 76% (61% to 87%) and its specificity 100% (84% to 100%). Ear oximetry was done on 83 patients. Oximetry correctly diagnosed 45 of the 53 patients who had PFO in TEE and all of the 30 patients without PFO. Thus, the sensitivity of ear oximetry was 85% (72% to 93%) and its specificity 100% (88% to 100%). The interrater agreement was excellent (kappa value 0.94 for dye dilution and 0.90 for oximetry). CONCLUSIONS: Dye dilution and oximetry are both sensitive and specific methods for the detection of PFO. Oximetry has the following primary advantages over the currently available diagnostic methods: it is noninvasive, safe, and inexpensive and causes no discomfort for the patient. We suggest that oximetry could be used as a first-line screening method for PFO in patients with cryptogenic stroke. Ear oximetry also has potential use in epidemiological studies.

Adult↗

PubMed1993

[Pulse oximetry in the air rescue service. 2: Methods of increasing the stability of pulse oximetry measurements--ECG-synchronized pulse oximetry and adhesive sensors].

Pulse oximetric monitoring in air rescue service (rescue helicopter) is primarily influenced by motion artifacts (especially those of a passive nature), by low perfusion and by the problem of probe dislocation. In a prospective study involving 162 unselected emergency patients treated by the medical team of the emergency helicopter service "Christoph 22" (Ulm), we studied the possibility of reducing these adverse factors by applying available state-of-the-art technology, such as ECG-synchronization and adhesive probes. By applying the thus modified methods of monitoring, the interference factor was reduced to S = 0.056, that is only 5.6% of measurement time was adversely effected. The increase in measurement stability resulted from the reduction in number of described artifacts (motion artifacts and low perfusion), as well as from the reduction in duration of interfered measurement time. ECG-synchronization very effectively influenced the passive motion artifacts. Their frequency was reduced by the factor 8.2, respectively 42. An effective reduction in number of probe dislocations can be achieved by applying adhesive probes. The high costs of such probes presently limits their application. Radiation can be eliminated by redesigning the probe. ECG-synchronization of pulse oximetric signal has proved to be a method to reduce the artifacts frequently experienced in air rescue and has considerably contributed to the increase of emergency patient safety.

Aircraft↗

PubMed2000

Comparison of a prototype esophageal oximetry probe with two conventional digital pulse oximetry monitors in aortocoronary bypass patients.

OBJECTIVE: Pulse oximetry (SpO2) is the non-invasive standard for monitoring arterial oxygen saturation in patients undergoing anesthesia, but is subject to external interference by motion artifact, peripheral vasoconstriction, and low cardiac output. We hypothesized that oximetry signals could be acquired from the esophagus when peripheral pulse oximetry is unobtainable. Therefore, we tested an esophageal stethoscope which incorporates transverse oximetry photodetectors and emitters in patients undergoing coronary bypass surgery. METHODS: Immediately after induction of general anesthesia in 10 coronary artery bypass (CABG) patients, Criticare and Nellcor digital probes were positioned on the left hand, concurrent with placement of an esophageal SpO2 probe. A computer recorded 5,910 matched oximetry signals every 15 sec during an average of 2.5 hrs. All SpO2 measurements were before, and immediately after non-pulsatile, hypothermic cardiopulmonary bypass. Data represent the percentage (median value [range]) of the total monitored time that a SpO2 value was displayed. RESULTS: The Nellcor (99.8%, range 6.5-100%) and Criticare (99.7%, range 36.6-100%) acquired and displayed saturation signals more frequently (p = 0.003) than the esophageal monitor (75.3%, range 42.1-95.8%). The two standard digital oximeters had a mean difference of 0.9%, with a standard deviation of the differences of 0.9. The esophageal probe had a mean difference of -5.2% and -4.8%, with standard deviation of differences of 8.0 and 7.7 (compared to the Nellcor and Criticare monitors, respectively). A second-generation prototype shielded from electrocautery interference was tested in an additional 4 patients. The shielded prototype displayed signals more frequently (96.7%, range 68.4-100%) than the original esophageal prototype. CONCLUSIONS: Digital pulse oximetry failure is common in CABG patients, probably because of marginal cardiac output and peripheral vasoconstriction associated with hypothermia. Our study could not confirm that esophageal technology, which utilizes the esophagus as a site of transflectance oximetry, was superior to conventional digital pulse oximetry.

Adult↗

PubMed1993

Randomized evaluation of pulse oximetry in 20,802 patients: I. Design, demography, pulse oximetry failure rate, and overall complication rate.

BACKGROUND: Although pulse oximetry is currently in widespread use, there are few data documenting improvement in patient outcome as a result of the use of oximetry. The authors describe the study design, patient demographic findings, data validation, pulse oximetry failure rate, and overall postoperative complication rates in the first large prospective randomized multicenter clinical trial on perioperative pulse oximetry monitoring. METHODS: In five Danish hospitals, by random assignment, monitoring did or did not include pulse oximetry for patients 18 yr of age and older, whether scheduled for elective or emergency operations, or for regional or general anesthesia, except during cardiac and neurosurgical procedures. Operational definitions were established for perioperative events and postoperative complications. The data were collected preoperatively, during anesthesia, in the postanesthesia care unit, and until the day of discharge from the hospital or the seventh postoperative day. RESULTS: Of 20,802 patients, 10,312 were assigned to the oximetry group and 10,490, to the control group. In general, the demographic data, patient factors, and anesthetic agents used were distributed evenly. A slight intergroup difference was found in the distribution of age, duration of surgery, some types of surgery, and some types of anesthesia. The total failure rate of the oximetry was 2.5%, but it increased to 7.2% in patients with American Society of Anesthesiologists physical status 4 (P < 0.00001). In 14.9% of the patients, one or more events occurred in the operating room and 13.5% in the postanesthesia care unit. The overall postoperative complication rate was 9.7%. The total rates of cardiovascular and respiratory complications were 2.78% and 3.50%, respectively. Within the first seven postoperative days, 0.47% of the patients died. Anesthesia was not thought to have been solely responsible for any death, but in 7 patients (1 per 3,365), it was a possible contributory factor. CONCLUSIONS: Despite the finding of a few significant inter-group differences, the randomization was well balanced with a high validity of data. The overall postoperative complication rate was similar to that in other recent morbidity and mortality studies.

Adult↗

PubMed1996

Comparison of oxygen saturation by pulse oximetry and co-oximetry during exercise testing in patients with COPD.

INTRODUCTION: Measurement of oxygen saturation by pulse oximetry (SpO2) is frequently performed during exercise testing of patients with COPD to monitor for hypoxemia. The purpose of this study was to assess the accuracy and precision of pulse oximetry during exercise. We hypothesized that the SpO2 would more closely reflect oxygen saturation as measured by co-oximetry (SaO2) when it was corrected for carboxyhemoglobin (COHb). We also hypothesized that SpO2 would more closely reflect SaO2 when the pulse rate by oximeter was equivalent to the heart rate by ECG. Finally, we hypothesized that SpO2 would be a better measure of SaO2 at maximal workloads than at rest or submaximal workloads. METHODS: Eight white men with severe COPD (mean +/- SD FEV1, 0.91 +/- 0.37) underwent progressive, symptom-limited exercise testing by cycle ergometry. SaO2 was measured from arterial blood at each workload using a co-oximeter. SpO2 and pulse rate were obtained by a pulse oximeter (Ohmeda 3700). Heart rate was continuously monitored by ECG. RESULTS: Reliable oximetric values as determined by a dicrotic notch in each waveform and adequate signal intensity were obtained in all eight patients. SpO2 was a moderately accurate measure of SaO2 (bias, 1.7%; precision, 2.9). The bias actually increased (4.1%) when SpO2 was corrected for COHb. Accuracy of SpO2 was not improved when pulse rate by oximetry and heart rate by ECG were equivalent, nor was the accuracy improved at maximal workloads relative to submaximal workloads during the exercise test. CONCLUSION: Oxygen saturation as measured by pulse oximetry (SpO2) in patients with COPD undergoing exercise testing is not sufficiently accurate to replace SaO2 as the gold standard for oxygen saturation.

Carboxyhemoglobin↗

PubMed1999

[Clinical importance of fetal pulse oximetry. II. Comparative predictive values of oximetry and scalp pH. Multicenter study].

OBJECTIVE: To compare the predictive value of intrapartum fetal pulse oximetry to that of fetal blood analysis for an abnormal neonatal outcome in case of abnormal fetal heart rate (FHR). STUDY DESIGN: A prospective multicenter observational study, from June 1994 to November 1995. Fetal oxygen saturation was continuously recorded using a Nellcor N-400 fetal pulse oximeter in case of abnormal FHR during labor. Simultaneous readings of fetal oxygen saturation and fetal blood analysis obtained before birth, i.e. either at full dilatation, or before cesarean section when indicated, were compared with the neonatal status. The criteria for an abnormal neonatal outcome were 1) an umbilical arterial blood pH < or = 7.15 and 2) a combined variable including: 5 min. Apgar score < or = 7, umbilical arterial pH < or = 7.15, secondary respiratory distress, transfer in a neonatal care unit, or neonatal death. RESULTS: At a 7.20 threshold for fetal scalp pH, and 30% for fetal oxygen saturation (i.e. the tenth centile in the study population), the predictive value of fetal pulse oximetry was similar to that of fetal blood analysis for an arterial umbilical pH < or = 7.15, and for an abnormal neonatal outcome (positive predictive value 56% vs 55%, negative predictive value 81% vs 82%, sensitivity 29% vs 35%, and specificity 93% vs 91% respectively). The receiver operating curve showed similar performance of either technique for cut-off values < or = 7.20 for fetal blood pH and < or = 30% for fetal oxygen saturation, whereas fetal pulse oximetry became superior at higher thresholds. CONCLUSION: The predictive value of intrapartum fetal pulse oximetry can be favorably compared with that of fetal blood analysis. Randomized controlled management trials can now be performed to assess potential clinical benefits of this new tool.

Female↗

PubMedDate not supplied

Correlation of pulse oximetry and co-oximetry.

Pulse oximetry is an important advancement in noninvasive monitoring and assessment of arterial blood oxygenation. The purpose of this study was to assess the correlation of arterial oxygen saturation (SaO2) and pulse oximetry (SpO2) in critically ill patients using the ear and finger probes. Arterial oxygen saturation was measured simultaneously by pulse oximetry with a finger and ear probe and an arterial blood gas sample. Results indicated that SpO2 does trend SaO2 but it appears that SpO2 measured by the finger probe is more closely correlated to SaO2 than SpO2 measured with an ear probe in this study sample.

Adolescent↗

PubMedDate not supplied

[Cerebral oximetry in neurosurgical patients with cerebrovascular diseases. II. Comparison of electrophysiological methods of examination and cerebral oximetry].

Simultaneous monitoring by cerebral oximetry and electrophysiological methods (electroencephalography and electrocorticography) was performed in 21 patients with arterial cerebral aneurysms during direct intracranial interventions, endovascular interventions, and Matas' test. Electrophysiological methods are sufficiently accurate indicators of cerebral ischemia even at a functionally reversible level. The results of simultaneous monitoring were similar in 80% cases, indicating cerebral ischemia even at functionally reversible level, which was detected by both electrophysiological methods and cerebral oximetry. Variously directed shifts were detected in 4 cases; the causes are discussed. Cerebral oximetry detects cerebral ischemia with a sensitivity similar to that of electrophysiological methods. The method does not depend on temperature or anesthetics. Limitations of the method are due to its local application.

Adult↗

PubMed1990

[Can oximetry contribute to the detection of apnea? The use of a mathematical analysis of the oximetry signal].

The aim of this study was to test the efficacy of nocturnal oximetry as a means of continuous recording of SaO2 in the identification of apnoeic events in the recognition of non-apnoeic desaturation. The oscillations of SaO2 in relation to successive periods of apnoea during the course of the sleep apnoea syndrome (SAS) or with apnoeic episodes in patients with chronic airflow obstruction (BPCO) or restricted disease, were identified using a new delta index quantifying the variations of SaO2 during the night. 26 successive patients in whom there was an indication for nocturnal oximetry were included in a prospective study comparing nocturnal oximetry and polysomnography during 34 nights. In the apnoeic patients we found a strong correlation (r = .85. p. less than .01) between the apnoeic period and the delta index. In BPCO the number of apnoea was correlated with the delta index (r = .96. p. less than .01). A minimal threshold of the delta index fixed at 1.5 was satisfactory for detecting apnoea if the initial SaO2 was less than 93%. The value of the adequate for affected detection ought to be fixed at .8 (95% sensitivity) when the initial SaO2 was greater than 93%. A detection of apnoeic events thus seems possible by this method.

Apnea↗

PubMed1992

Tongue oximetry in children with extensive thermal injury: comparison with peripheral oximetry.

We undertook a prospective study of standard peripheral pulse oximetry versus a modified pulse oximeter probe applied to the tongue in order to determine the efficacy of this alternative monitoring site in children with thermal injuries. Ten patients with a mean age (+/- SD) of 7.5 +/- 4.5 yr were studied on 15 occasions. The mean weight (+/- SD) was 31.4 +/- 13.7 kg and percent surface area burn (+/- SD) was 56 +/- 21%. A total of 1,992 min of anaesthesia time was monitored. Both sites functioned simultaneously 47% of the time; the lingual but not the peripheral site functioned 28% of the time and only the peripheral site and not the lingual functioned 22% of the time. Neither site functioned 3% of the time. The tongue oximeter provided 563 min more monitoring time than the peripheral sites. The tongue oximeter also functioned in children with peripheral vasoconstriction when the peripheral sensor failed and was less susceptible to electrocautery interference. The tongue oximeter is a reasonable adjunct but not a substitute for peripheral oximetry since its application is limited to paralyzed, intubated patients.

Adolescent↗

PubMed1997

Multicenter study on the clinical value of fetal pulse oximetry. I. Methodologic evaluation. The French Study Group on Fetal Pulse Oximetry.

OBJECTIVE: Our purpose was to evaluate the feasibility of intrapartum fetal pulse oximetry, the distribution of fetal oxygen saturation values, and the relationship with the neonatal outcome in a population with an abnormal fetal heart rate. STUDY DESIGN: A prospective multicenter observational study was performed from June 1994 to November 1995. Fetal oxygen saturation was continuously recorded with use of a Nellcor N-400 fetal pulse oximeter in case of an abnormal fetal heart rate during labor. Simultaneous readings of fetal oxygen saturation and fetal blood analysis were obtained at inclusion and before birth. Feasibility, adverse effects, distribution of fetal oxygen saturation values, and relationship with neonatal outcome were assessed. RESULTS: One hundred seventy-four patients were included. From 172 attempted sensor placements, the procedure was impossible in three cases and fetal oxygen saturation values were obtained in 164 cases (95.3%). Physicians considered sensor placement an easier task than an attempt at fetal blood analysis (easy in 87.5% vs 78.9% for fetal blood analysis, p = 0.03). The mean reliable signal time (+/- SD) was 64.7% +/- 32% during the first stage. There were no serious adverse effects in the study population. The mean fetal oxygen saturation during the first stage of labor was 42.2% +/- 8.0% (10th to 90th percentile range 30% to 53%). Fetal oxygen saturation was significantly correlated with scalp pH (r = 0.29, p = 0.01) but not with neonatal umbilical artery pH or gas values. There was a significant association between low fetal oxygen saturation (< 30%) and poor neonatal condition. CONCLUSION: The feasibility of fetal pulse oximetry is satisfactory in clinical practice. It is easy to use and provides a fair rate of recorded values, even in a population with suspicion of fetal distress. A low fetal oxygen saturation is significantly associated with an abnormal neonatal outcome.

Adult↗

PubMed2000

A pilot study of pharyngeal pulse oximetry with the laryngeal mask airway: a comparison with finger oximetry and arterial saturation measurements in healthy anesthetized patients.

UNLABELLED: We compared pharyngeal SpO(2) by using the laryngeal mask airway (LMA) to finger SpO(2) and oxygen saturation from arterial blood samples (SaO(2)). We studied 20 hemodynamically stable, well oxygenated, anesthetized patients (ASA physical status I-III, aged 18-80 yr). A single-use pediatric pulse oximeter was attached to the back plate of a size 5 LMA. Pharyngeal and finger SpO(2) (dominant index finger) and SaO(2) (nondominant radial artery) were measured with the cuff volume at 0-40 mL in the neutral position. The intracuff pressure was then set at 60 cm H(2)O in the neutral position, and readings were taken with the head-neck flexed, extended, and rotated. SaO(2) was the same as pharyngeal SpO(2) at 20 and 30 mL cuff volume, but higher than pharyngeal SpO(2) at all other cuff volumes and head-neck positions (P < 0.04). SaO(2) was always higher than finger SpO(2) (P < 0.01). Pharyngeal SpO(2) was higher than finger SpO(2) at cuff volumes 10-40 mL and in the flexed and rotated head-neck positions (all: P < 0.007), but was lower at 0 cuff volume (P < 0.0001) and similar in the extended head-neck position. There was an increase in pharyngeal SpO(2) between 0 and 10 mL cuff volume (P < 0.0001), but no changes thereafter. Pharyngeal SpO(2) was similar in the flexed, rotated and extended head-neck positions. Pharyngeal SpO(2) agrees more closely with SaO(2) (mean difference < 0.7%) than finger SpO(2) (mean difference > 1.1%) at 10-40 mL cuff volume and in head-neck flexion. The standard error of limits was identical (0.09) for both finger SpO(2) and pharyngeal SpO(2) if data at 0 cuff volume are excluded. We conclude that pharyngeal SpO(2) with the LMA is feasible and generally provides more accurate readings than finger SpO(2) in hemodynamically stable, well oxygenated, anesthetized patients. IMPLICATIONS: Pharyngeal oximetry with the laryngeal mask airway is feasible and generally provides more accurate readings than finger oximetry in hemodynamically stable, well oxygenated, anesthetized patients.

Adult↗

PubMed1999

[Clinical importance of fetal pulse oximetry. I. Methodological evaluation. Multicenter study. French Study Group on Oximetry of Fetal Pulse].

OBJECTIVE: To evaluate the feasibility of intrapartum fetal pulse oximetry, the distribution of fetal oxygen saturation values, and the relation with the neonatal outcome in a population with an abnormal fetal heart rate (FHR). STUDY DESIGN: A prospective multicenter observational study, from June 1994 to November 1995. Fetal oxygen saturation was continuously recorded using a Nellcor N-400 fetal pulse oximeter in case of abnormal FHR during labor. Simultaneous readings of fetal oxygen saturation and of fetal blood analysis (FBA) were obtained at inclusion and before birth. Feasibility, adverse effects, distribution of fetal oxygen saturation values and relation with neonatal outcome were assessed. RESULTS: 74 patients were included. From 172 attempted sensor placements, the procedure was impossible in three cases and fetal oxygen saturation values were obtained in 164 cases (95.3%). Physicians considered sensor placement an easier task than FBA attempt (easy in 87.5% vs 78.9% for FBA, p = 0.03). The mean reliable signal time (+/- SD) was 64.7 +/- 32% during the first stage. There were no serious adverse effects in the study population. The mean fetal oxygen saturation during the first stage of labor was 42.2 +/- 8.0% (10th-90th centile range: 30-53%). Fetal oxygen saturation was significantly correlated with scalp pH (r = 0.29; p = 0.01) but not with neonatal umbilical artery pH or gas values. There was a significant association between a low fetal oxygen saturation (< 30%) and a poor neonatal condition. CONCLUSION: The feasibility of fetal pulse oximetry is satisfactory in clinical practice. It is easy to use and provides a fair rate of recorded values, even in a population with suspicion of fetal distress. A low fetal oxygen saturation is significantly associated with an abnormal neonatal outcome.

Adult↗

PubMed1994

[Noninvasive patient observation in veterinary medicine: pulse oximetry and capnography. I. Pulse oximetry].

Two non-invasive continuous techniques for monitoring the respiratory function during anaesthesia have been established during the last year: pulse oximetry for monitoring the adequate oxygen supply and capnography for measuring the carbon dioxide elimination. In human medicine both are accepted as essential monitors with great reliability. Whether clinical use and interpretation can be transferred to animals without any restrictions will be discussed by looking on the physical and engineering background as well as the physiologic interpretation of the measured variable and their capability to detect critical events during administration of anaesthesia. Part I: Pulse oximetry measures the arterial oxygen saturation continuously and non-invasively. Its application in veterinary medicine must be discussed critically concerning the method as well as the interpretation. The information obtained is very different during injectable and inhalant anaesthesia. Respiratory depression is easy to detect while the animal breathes room air spontaneously. Is the inspired air enriched with oxygen, like during inhalant anaesthesia, normal values of oxygen saturation can mask the respiratory insufficiency and may give a false sense of security.

Anesthesia↗