Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “OXIMETRY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMedDate not supplied

Pulse oximetry for the assessment of autonomic neuropathy in diabetic patients.

Altered vascular responses to various thermal stimuli correlate well with the changes of autonomic neuropathy. These responses were assessed by the use of pulse oximetry. Standard cardiac autonomic function tests were performed in normal subjects (n = 12), diabetic patients without autonomic neuropathy (n = 8), and diabetic patients with autonomic neuropathy (n = 7). Autonomic functions in the same patients then were assessed by estimating the severity of vasospasm in response to cold stimulus with the help of pulse oximetry. Percentage fall in oxygen saturation at 15, 30, 60, 90, and 120 sec of exposure to cold stimulus was recorded on pulse oximeter. Time required for recovery and presence or absence of rebound rise following removal of cold stimulus were noted. In diabetics with autonomic neuropathy, the rate of fall in percentage oxygen saturation was significantly slower (p < 0.0001), less intense (p < 0.0001) and with delayed subsequent recovery (p = 0.013), compared to normal subjects. Rebound rise in oxygen saturation was absent in all the diabetics with autonomic neuropathy, compared to 2 of 12 normal subjects (p < 0.0001). We conclude that pulse oximetry may be a potentially useful, simple, and noninvasive bedside method for assessment of diabetic autonomic neuropathy.

Adult↗
PubMed2005

Oximetry-derived perfusion index for intraoperative identification of successful thoracic sympathectomy.

BACKGROUND: Endoscopic thoracic sympathectomy treats patients with hyperhidrosis. Laser Doppler flow and changes in palmar temperature have been advocated for intraoperative monitoring. The pulse oximetry-derived perfusion index (PI) is used to quantify pulsatile blood flow at the pulse oximeter. Upper limb sympathectomy is associated with increased flow to the ipsilateral extremity; thus we postulate that it will increase PI. We evaluated changes in intraoperative PI as a monitor of successful thoracic sympathectomy. METHODS: After institutional review board approval and informed consent, 10 adult patients undergoing bilateral endoscopic thoracic sympathectomy under general anesthesia were studied. Finger pulse-oximetry probes were placed on each hand, and reference probes on each earlobe. Hemodynamic variables and PI were continuously monitored. Data were collected immediately before and every minute after sympathectomy for 5 minutes. Anesthetic management remained constant throughout. A successful sympathectomy was defined by a twofold increase in PI on the ipsilateral arm. Data were analyzed with analysis of variance and Student's t tests; a p < 0.05 was considered significant. RESULTS: Baseline oximetric waveforms were adequate in all subjects. Right sympathectomy was associated with a 372% increase in PI (p < 0.0001), and left sympathectomy with a 316% increase in PI (p < 0.029). This occurred as early as 1 minute after transection of the sympathetic chain. The PI in the reference probes as well as the hemodynamics remained constant. All patients had postoperative resolution of their hyperhidrosis symptoms. CONCLUSIONS: In patients with hyperhidrosis of the upper extremity, the intraoperative PI derived from pulse oximetry is an additional indicator of successful thoracic sympathectomy.

Adolescent↗
PubMed2004

Fetal pulse oximetry: a critical appraisal.

Despite 40 years of cumulative clinical experience, and a number of randomized clinical trials, electronic fetal heart rate monitoring is perceived by many obstetrical caregivers as a suboptimal method of intrapartum fetal assessment. Fetal pulse oximetry emerged 15 years ago as a promising new technology intended to improve assessment of fetal condition during labor. A large amount of physiologic data and one large randomized clinical trial have brought this technology into clinical practice. We know that fetal acidemia is rare when the arterial oxygen saturation is >30% but fetal pulse oximetry as currently understood and applied does not reduce the overall cesarean rate. Thus, many clinicians remain unconvinced of the benefit of this technology and its utilization has stalled in the US and Europe. We need to further understand if there is a way to use fetal pulse oximetry in the setting of labor dystocia and a non-reassuring fetal heart rate pattern. Although hypoxemia is an accepted mechanism of fetal brain injury, other potential mechanisms should be explored. Current controversies and fertile areas of research are presented.

Acid-Base Imbalance↗
PubMed2004

Effect of RSR13, an allosteric hemoglobin modifier, on oxygenation in murine tumors: an in vivo electron paramagnetic resonance oximetry and bold MRI study.

PURPOSE: RSR13, an allosteric modifier of hemoglobin, reduces hemoglobin-oxygen binding affinity facilitating oxygen release from hemoglobin, resulting in increases in tissue pO(2). The purpose of this study was noninvasively to monitor the time course and effect of RSR13 on tumor oxygenation, directly using in vivo electron paramagnetic resonance (EPR oximetry), and indirectly using blood oxygen level dependent magnetic resonance imaging (BOLD MRI). METHODS AND MATERIALS: The study was performed in transplanted radiation-induced fibrosarcoma tumors (RIF-1) in 18 female C3H/HEJ mice, which had two lithium phthalocyanine (LiPc) deposits implanted in the tumor when the tumors reached about 200-600 mm(3). Baseline EPR measurements were made daily for 3 days. Then, for 6 consecutive days and after an initial baseline EPR measurement, RSR13 (150 mg/kg) or vehicle (same volume) was injected intraperitoneally, and measurements of intratumoral oxygen were made at 10-min intervals for the next 60 min. In each mouse, every third day, instead of EPR oximetry, BOLD MRI measurements were made for 60 min after administration of the RSR13. RESULTS: Based on EPR measurements, RSR13 produced statistically significant temporal increases in tumor pO(2) over the 60-min time course, which reached a maximum at 35-43 min postdose. The average time required to return to the baseline pO(2) was 70-85 min. The maximum increase in tumor tissue pO(2) values after RSR13 treatment from Day 1 to Day 5 (8.3-12.4 mm Hg) was greater than the maximum tumor tissue pO(2) value for Day 6 (4.7 mm Hg, p < 0.01). The maximum increase in pO(2) occurred on Day 2 (12.4 mm Hg) after RSR13 treatment. There was little change in R(2)*, indicating that the RSR13 had minimal detectable effects on total deoxyhemoglobin and hemoglobin-oxygen saturation. CONCLUSION: The extent of the increase in tumor pO(2) achieved by RSR13 would be expected to lead to a significant increase in the effectiveness of tumor radiotherapy. The lack of a change in the BOLD MRI signal suggests that the tumor physiology was largely unchanged by RSR13. These results illustrate a unique and useful capability of in vivo EPR oximetry and BOLD MRI to obtain repeated measurements of tumor oxygenation and physiology. The dynamics of tumor pO(2) after RSR13 administration may be useful for the design of clinical protocols using allosteric hemoglobin effectors.

Aniline Compounds↗
PubMed2005

Intraoperative determination of intestinal viability: a comparison with transserosal pulse oximetry and histopathological examination.

BACKGROUND: In this study, we aimed to measure the O2 saturation of ischemic intestinal segments and the relationship between these measures and concomitant pathological gradings. MATERIALS AND METHODS: We used 14 New Zealand White rabbits, anesthetized with a combination of 80 mg/kg (i.m.) Ketamine hydrochloride and 10 mg/kg Acepromazine (i.m.). The superior mesenteric artery (SMA) was explored, and O2 saturation was measured by pulse oximetry 5 cm proximal to the ileocecal valve at the 0th hour. At the same time a 0.5-cm full-thickness wedge biopsy was taken from the same region. Thereafter, the SMA was ligated and the abdomen was closed. All rabbits were undertaken relaparotomy at the 4th hour; O2 saturation was measured by pulse oximetry at 5 cm away from the region of the first biopsy and a 0.5-cm full-thickness wedge biopsy was taken. The abdomen was then closed. The same procedure was performed at the 8th and the 12th hour. Mucosal hemorrhage, transmural congestion, mucosal necrosis, and transmural necrosis were examined in the specimens. RESULTS: Pathologically, transmural necrosis was concomitant with 64% O2 saturation (sensitivity: 100%; specificity: 86%). Mucosal necrosis was concomitant with 76% O2 saturation values (sensitivity: 100%; specificity: 75%). Transmural congestion was concomitant with 81% O2 saturation values (sensitivity: 89%; specificity: 58%). Mucosal hemorrhage was concomitant with 91% O2 saturation (sensitivity: 100%; specificity: 31%). CONCLUSION: O2 saturation measures > 76% may indicate reversible changes as mucosal necrosis, transmural congestion, or mucosal hemorrhage, and O2 saturation measures < 64% may indicate permanent transmural necrosis. As a result, intraoperative evaluation of intestinal viability by pulse oximetry may give us an idea about the degree of pathological changes and subsequently might reduce the number of second-look operations.

Animals↗
PubMed1994

Artifacts in fetal pulse oximetry: nonarterial pulsatile signals.

OBJECTIVE: We wished to investigate the effect of caput succedaneum on pulse oximetry readings. STUDY DESIGN: Oxygen saturation was measured by reflection pulse oximetry on various sites of scalps of 18 healthy neonates. The pulse rate obtained from the oximeter was checked against the heart rate from the electrocardiogram to see whether they were in agreement and synchronized. RESULTS: Nonsynchronized saturation values had a much wider range (30 to 97 vs 70 to 98) and a significantly lower mean (70 vs 84) than did synchronized values. Synchronized readings were obtainable in all 18 subjects over the temporal region but in only 39% of cases over the occipital region. Fourteen neonates had caput succedaneum, and in nine (61%) of these synchronized readings were not possible. It was noted that falsely low saturation values can be derived from pulsating waveforms, which have a slower rate than the electrocardiogram rate. CONCLUSIONS: The observed low pulsation rate is either of venous origin or represents modulated transmission of arterial signal through an edematous or congested scalp. This artifact will result in nonarterial oxygen saturation readings, and its exclusion is of importance in the development of pulse oximetry for intrapartum monitoring of the fetus.

Artifacts↗
PubMed1999

Doppler ultrasonographic evidence of intrapartum brain-sparing effect in fetuses with low oxygen saturation according to pulse oximetry.

OBJECTIVE: This study was undertaken to verify by means of Doppler ultrasonography and simultaneous fetal pulse oximetry the redistribution of fetal blood flow in favor of the brain during intrapartum hypoxemia. STUDY DESIGN: During labor 11 term fetuses with abnormal heart rate patterns and arterial oxygen saturation <30% and 14 control term fetuses with normal oxygen saturation were simultaneously monitored by pulse oximetry and Doppler ultrasonography. The results were compared with the Student t test. RESULTS: The blood flow velocity in the middle cerebral artery was significantly higher in the presence of reduced oxygen saturation, implying lower pulsatility and resistance indices (P <.001). The reduction of blood flow in the umbilical artery was not significant (P =.61). CONCLUSION: Simultaneous intrapartum pulse oximetry and Doppler ultrasonography proved that reduced arterial oxygen saturation (<30%) is associated with profound changes in fetal hemodynamics and could be tolerated for only a limited period, which should be the subject of further studies.

Adult↗
PubMed1997

Standardized exercise oximetry predicts postpneumonectomy outcome.

BACKGROUND: We have developed a safe, simple, and easily performed standardized exercise oximetry outpatient test to assess patients undergoing lung resections. We studied its ability to predict outcome after pneumonectomy in 46 consecutive patients over a 5-year period. METHODS: Room air oximetry is initially performed at rest. The patient then begins to exercise on a stair-stepper apparatus (Stamina Stepper), which provides uniform resistance to stepping. Oxygen saturation values are noted at 10, 20, and 30 steps, equivalent to climbing three flights of stairs. Group 1 consisted of the patients who either had a resting saturation less than 90%, or desaturation greater than or equal to 4% during exercise. Group 2 consisted of all patients who had a preoperative forced expiratory volume in 1 second of 60% or less. Group 3 consisted of all patients who had a predicted postoperative forced expiratory volume in 1 second of 40% or less. Group 4 consisted of patients who had a predicted postoperative diffusing capacity of 40% or less. RESULTS: There were four deaths (8.6%), 12 patients (26%) remained in the intensive care unit 4 or more days, and 11 patients (23%) suffered major morbidity. Desaturation during exercise (group 1) significantly predicted longer intensive care unit stay (p = 0.0002) and incidence of major morbidity (p < 0.0001). Groups 2, 3, and 4 were not significantly predictive of either longer intensive care unit stay or major morbidity. CONCLUSIONS: Standardized exercise oximetry performed in the outpatient facility is highly predictive of major morbidity and prolonged intensive care unit stay after pneumonectomy.

Adult↗
PubMed2002

In vivo assessment of nodularin-induced hepatotoxicity in the rat using magnetic resonance techniques (MRI, MRS and EPR oximetry).

Acute nodularin-induced hepatotoxicity was assessed in vivo, in rats using magnetic resonance (MR) techniques, including MR imaging (MRI), MR spectroscopy (MRS), and electron paramagnetic resonance (EPR) oximetry. Nodularin is a cyclic hepatotoxin isolated from the cyanobacterium Nodularia spumigena. Three hours following the intraperitoneal (i.p.) administration of nodularin (LD50), a region of 'damage', characterized by an increase in signal intensity, was observed proximal to the porta hepatis (PH) region in T2-weighted MR images of rat liver. Image analysis of these regions of apparent 'damage' indicated a statistically significant increase in signal intensity around the PH region following nodularin administration, in comparison with controls and regions peripheral to the PH region. An increase in signal intensity was also observed proximal to the PH region in water chemical shift selective images (CSSI) of nodularin-treated rat livers, indicating that the increased signal observed by MRI is an oedematous response to the toxin. Microscopic assessment (histology and electron microscopy) and serum liver enzyme function tests (aminotransferase (ALT) and aspartate ALT (AST)) confirmed the nodularin-induced tissue injury observed by MRI. In vivo and in vitro MRS was used to detect alterations in metabolites, such as lipids, Glu+Gln, and choline, during the hepatotoxic response (2-3 h post-exposure). Biochemical assessment of perchloric acid extracts of nodularin-treated rat livers were used to confirm the MRS results. In vivo EPR oximetry was used to monitor decreasing hepatic pO2 (approximately 2-fold from controls) 2-3 h following nodularin exposure. In vivo MR techniques (MRI, MRS and EPR oximetry) are able to highlight effects that may not have been evident in single end point studies, and are ideal methods to follow tissue injury progression in longitudinally, increasing the power of a study through repeated measures, and decreasing the number of animals to perform a similar study using histological or biochemical techniques.

Alanine Transaminase↗
PubMed2002

Intrapartum cardiotocography and fetal pulse oximetry in assessing fetal hypoxia.

OBJECTIVES: A retrospective analysis of short-term variability (STV), a cardiotocography (CTG) parameter, in relation to fetal blood saturation values (FSpO(2)) obtained by fetal pulse oximetry. METHODS: The study included 26 healthy pregnant women monitored continuously during delivery with both cardiotocography and fetal pulse oximetry. RESULTS: Lower FSpO(2) values were observed in the group showing STV levels 6.0 ms (34.4+/-2.9% vs. 43+/-7.2%; P<0.001). A positive correlation was found between STV levels <or=6.0 ms and mean FSpO(2) values in the 2nd stage of labor. CONCLUSIONS: 1. A significant relationship was observed between short-term variability in the cardiotocographic records and fetal blood saturation levels in the 2nd stage of labor. 2. Fetal pulse oximetry can be valuable in assessing fetal wellbeing, especially when CTG records are abnormal.

Cardiotocography↗
PubMed1994

A practical and reliable method of measuring blood pressure in the neonate by pulse oximetry.

OBJECTIVE: We investigated the reliability of the plethysmographic waveform of the pulse oximeter to measure systolic blood pressure in sick neonates. METHODS: Fifty infants admitted to the neonatal intensive care unit, with indwelling arterial catheters placed for their ongoing care, were enrolled. Median gestational age was 31 weeks (range, 24 to 40 weeks), and the mean birth weight was 1711 gm (range, 546 to 3856 gm). Blood pressure was recorded by an oscillometric method as well as from a transducer connected to an arterial catheter. Additionally, pulse oximeter blood pressures were obtained by gradually inflating an appropriately sized blood pressure cuff in increments of 2 to 5 mm Hg, on the same extremity as the oximeter probe, until the waveform just disappeared. The cuff was then rapidly inflated another 20 mm Hg and then gradually deflated in increments of 2 to 5 mm Hg until the waveform reappeared on the oximeter screen display. The pulse oximeter blood pressures were calculated both as the blood pressure noted at disappearance of the pulse oximeter waveform and as the blood pressure noted by the average pulse oximeter blood pressure at the disappearance and reappearance of the waveform. The mean intraarterial systolic blood pressure was 54 mm Hg (range, 36 to 82 mm Hg). RESULTS: Blood pressures obtained by pulse oximetry showed a significantly better correlation with intraarterial measurements in comparison with those obtained by oscillometric instruments. Additionally, the limits of agreement (mean difference +/- 2 SD) between blood pressures obtained by intraarterial measurements and those obtained by pulse oximetry were within a clinically acceptable range as opposed to those obtained by the comparison of intraarterial and oscillometric methods. CONCLUSION: Measurements of blood pressure in the neonate by means of pulse oximetry waveform analysis are easily obtainable and more accurate than those obtained by the oscillometric method.

Blood Pressure Determination↗
PubMed2000

Continuous pulse oximetry in acute hemiparetic stroke.

BACKGROUND AND PURPOSE: Hypoxemia can adversely affect ischemic brain tissue in laboratory animals. The aim of this study was to assess the value of early continuous monitoring with pulse oximetry in detecting arterial oxygen desaturations in patients with acute hemiparetic stroke, and the effects of oxygen administration. METHODS: Over a period of 6 months 49 consecutive patients with acute hemiparetic stroke of </=12 h duration were monitored for the first 48 h with pulse oximetry. Patients in whom arterial oxygen saturation (SaO(2)) fell beneath 96% for a period longer than 5 min were treated with oxygen administered via nasal prongs or oxygen mask. RESULTS: Thirty-one patients (63.3%) developed arterial oxygen desaturations. Of these patients 28 could effectively be treated with oxygen up to a flow-rate of 5 l/min. Only 3 patients required higher oxygen concentrations from 6 to 10 l/min. No acute adverse effects of oxygen treatment were observed. All patients with a history of cardiac and pulmonary disease developed drops in SaO(2). The occurrence of arterial oxygen desaturations was related to stroke severity (P=0.024), the presence of dysphagia (P=0.047), and older age (P=0.037). CONCLUSION: Patients with acute hemiparetic stroke frequently develop arterial oxygen desaturations. Continuous monitoring with pulse oximetry in this group of patients is a simple and useful method to detect drops in SaO(2) and to titrate oxygen administration.

Acute Disease↗
PubMed1996

Detection of pulpal circulation in vitro by pulse oximetry.

Evaluation of pulse oximetry as a potential method of determining pulp vitality was the subject of this research. An in vitro model of pulpal circulation was fabricated to test the design for a dental pulse oximetry sensor. Blood samples equilibrated with hypoxic gas mixtures were circulated through the model by a peristaltic pump. A pulse was simulated by introduction of gas bubbles into the blood circulation. Pulse oximeter readings for saturation were recorded and compared with blood gas analysis results. Statistical analysis revealed no difference between pulse oximetry and blood gas analysis with a highly significant correlation coefficient. Clinical evaluation of this application is currently in progress.

Dental Pulp↗
PubMed2002

Simultaneous use of intrapartum fetal pulse oximetry and amnioinfusion in meconium stained amniotic fluid.

OBJECTIVE: Fetal pulse oximetry is a minimally invasive, simple technique which continuously helps to reflect in utero well-being. The presence of meconium in the amniotic fluid may be a clinical sign of fetal hypoxaemia. Amnioinfusion has a beneficial effect on the incidence of meconium aspiration syndrome (MAS), and the presence of meconium below the level of the vocal cords. STUDY DESIGN: We studied the impact of amnioinfusion combined with fetal pulse oximetry on the incidence of meconium aspiration syndrome and operative delivery. RESULTS: The retrospective analysis revealed that the presence of meconium below the level of vocal cords was significantly reduced. The frequency of cesarean section is decreased, however, it did not reach statistical significance. CONCLUSION: Fetal pulse oximetry may be used in combination with amnioinfusion and cardiotocography (CTG) to reduce the risk of meconium aspiration syndrome and the number of instrumental deliveries and improve perinatal outcome.

Adolescent↗
PubMed1996

[Pulse oximetry in pediatrics].

Pulse oximetry has become the leading technique for monitoring hemoglobin oxygen saturation whenever a risk of hypoxia exists. It is based upon the principle of light absorbance of pulsatile arterial blood. Since it uses 2 wavelengths, it can only measure oxyhemoglobin and reduced hemoglobin. Thus, in case of increased methemoglobin or carboxyhemoglobin, pulse oximetry values are not reliable. Low tissue perfusion can also be responsible for inaccurate values. Nevertheless pulse oximetry is a reliable and easy-to-use technique in most of the clinical situations. This article reviews the physical basis, the reliability, the pediatric aspects, and the limitations of the technique.

Child↗
PubMed1997

False low pulse oximetry reading associated with the concomitant use of a peripheral nerve stimulator and an evoked-potential stimulator.

One of the sources of error in pulse oximetry readings is associated with an abnormal signal-to-noise ratio. The pulse oximeter distinguishes the light absorbance of arterial blood from that of other absorbers by differentiating between a constant component and a pulsating component. The pulsating component is almost exclusively the result of arteriolar bed pulsations. Because pulse oximetry is based on the assumption that arterial blood is the only pulsatile absorber, any other fluctuating phenomenon could constitute a source of error. We report a case in which a low pulse oximetry reading was associated with concomitant use of a pulse oximeter and a peripheral nerve stimulator on the same arm. Further tests conducted using a nerve stimulator and a sensory evoked potential stimulator with different amplitudes and frequencies confirmed the association and delineated the relationship between frequency and amplitude of stimulation and the degree of artificial desaturation. A theoretical explanation for this phenomenon is presented.

Electric Stimulation↗
PubMed1998

The use of near-infrared cerebral oximetry in awake carotid endarterectomy.

STUDY OBJECTIVE: To determine the utility of cerebral oximetry for monitoring the adequacy of cerebral blood flow (CBF) during carotid cross-clamp. DESIGN: Prospective study. SETTING: University hospital. PATIENTS: 16 consecutive ASA physical status III (or higher) patients for awake carotid endarterectomy (CEA). INTERVENTIONS: Regional cerebral oxygen saturation (SaO2) was monitored continuously during CEA, which was performed by the same surgeon, and with standard regional anesthetic, sedation, monitoring, and operative techniques. Data were recorded and analyzed using repeated measures analysis of variance (ANOVA). MEASUREMENTS AND MAIN RESULTS: 14 hemodynamically stable patients demonstrated significant decreases in cerebral SaO2 from baseline: 69 + 1.8% to 64 + 1.2% at carotid cross-clamp (p < 0.001). After 5, 10, and 15-minute cross-clamp time, cerebral SaO2 was 63 + 1.4%, 64 + 1.5%, and 63 + 1.4%, respectively (p < 0.001, vs. baseline). On cross-clamp removal, cerebral SaO2 rose significantly: 67 + 1.6% (p < 0.01 vs. 5, 10, and 15 min). Two hypotensive patients (mean arterial pressures of 40 and 43 mmHg) developed signs and symptoms of global cerebral ischemia, with a concomitant decrease in cerebral oximetry (40% and 48%, respectively). These changes resolved with correction of hypotension. CONCLUSION: Cerebral SaO2 decreased significantly on carotid cross-clamp in patients undergoing awake CEA. Hemodynamically stable patients demonstrated no evidence of regional brain failure when SaO2 decreased to 63% (mean decrease of 7.2%). Two hemodynamically unstable patients had evidence of global brain failure when SaO2 was less than 48% (mean decrease of 36%). Our findings suggest that cerebral oximetry reflects CBF, and it may be an effective, noninvasive method of monitoring regional cerebral oxygenation changes during CEA. Significant reductions in regional SaO2 may be tolerated without evidence of brain failure. Further studies are needed to define an SaO2 threshold that reflects regional brain failure.

Aged↗
PubMed1998

Screening patients in general practice with COPD for long-term domiciliary oxygen requirement using pulse oximetry.

Epidemiological data suggest long-term oxygen therapy (LTOT) delivered by oxygen concentrators in patients with severe hypoxic chronic obstructive pulmonary disease (COPD) is under-prescribed by General Practitioners (GPs) in England and Wales. One reason for this may be the unavailability to GPs of a measure of arterial oxygenation needed to fulfil the defined prescription criteria. Provision of a non-invasive measure of oxygenation may improve detection of hypoxic subjects and increase appropriate prescribing. This study aimed to evaluate pulse oximetry in a general practice setting and to screen for severe undetected hypoxaemia fulfilling the LTOT prescription criteria in patients with COPD. All COPD patients attending surgery in two practices were screened with oximeters for hypoxaemia. Those with an oxygen saturation of < or = 92% were referred to hospital for formal arterial blood gas analysis and an oxygen concentrator assessment. GPs were asked to evaluate their experience in the ease of use and application of oximetry. The number of patients receiving oxygen by concentrator before the study was compared with the national rate and the number after the study with the estimated need suggested by epidemiological studies. Over a 12-month period a total of 114 patients were screened in the two practices with a combined list size of 15,742. Thirteen patients had saturations of < or = 92%. Two refused and 11 underwent formal arterial gas analysis. Three had PaO2 < 7.3 kPa and new prescriptions for oxygen concentrators were made in these previously unsuspected severely hypoxaemic subjects as a result. One other hypoxaemic subject was referred and found to have another treatable medical condition. The initial prevalence of concentrator prescription (0.013% CI 0.003, 0.047) was similar to the national rate (0.024%) and the prevalence observed after screening (0.031%, CI 0.013, 0.073) fell within the lower suggested prescription need of previous epidemiological data (0.02-0.10%). All practitioners found the oximeters simple to use and helpful in assisting with assessment of the severity of their patient's condition. Oximetry provides a readily usable non-invasive method of screening and when applied to all COPD patients seen in general practice can reveal those fulfilling the criteria for long term oxygen who would otherwise not be identified as needing this treatment.

Aged↗