Oximetry

To assess the potential role of multiple bronchoalveolar lavages (BALs) in the treatment of children with lipoid pneumonia (LP). This prospective study included 10 children (7 female, 3 male) with LP secondary to mineral oil aspiration. The age ranged from 3 months to 7 years and 1-60 days history of mineral oil intake, with a 6 months clinic follow-up. High-resolution computer tomography (CT) was performed 1-7 days prior to treatment and 2-20 days after the last therapeutic BAL, and reviewed by two experienced chest radiologists. Oxygen saturation was measured with digital oximetry. Therapeutic BAL was performed weekly until BAL fluid was nearly transparent and the cell count returned to normal range values. In all children, the initial CT scans showed multifocal bilateral consolidation involving mainly the dorsal and central regions. The areas of consolidation had foci of decreased attenuation in eight patients. Following a total of 4-10 therapeutic BALs, the CT scans returned to normal in 3 patients, improved considerably in 5, and showed only slight improvement in 2. Oxygen saturation increased from 88.8 +/- 3.4% at presentation to 96.2 +/- 0.8% after treatment (P < 0.0001). Multiple lavages reduced (P < 0.003) numbers of lipid-laden macrophages and restored BAL cellularity to normal range values. Multiple therapeutic BAL of children with LP results in significant improvement of CT findings, oxygen saturation, restoration of BAL fluid cellularity and clinical recover without any evidence of respiratory distress at the end of treatment and 6 months after the last BAL.

Objectives: The objective of this study was to describe the prevalence of pneumonia-like signs and symptoms in patients admitted from the emergency department (ED) with a diagnosis of community acquired pneumonia (CAP) but subsequently discharged from the hospital with a nonpneumonia diagnosis. Methods: A retrospective, structured, chart review of ED patients with CAP at 3 academic hospitals was performed by trained extractors on all adult patients admitted for CAP. Demographic data, Pneumonia Patient Outcomes Research Team scores, and discharge diagnosis data (International Classification of Diseases, Ninth Revision [ICD-9] codes) were extracted using a predetermined case report form. Results: A total of 800 patients were admitted from the ED with a diagnosis of CAP from the 3 hospitals, and 219 (27.3%; 95% confidence interval [CI], 24-31) ultimately had a nonpneumonia diagnosis upon discharge. Characteristics of this group included a mean age of 62.6 years, 50% female, and a history of congestive heart failure (CHF) (14%) or cancer (12%). After excluding patients with missing data, 123 patients (65%) had an abnormal chest x-ray, and 13% had abnormal oxygen saturation. Cough, sputum production, fever, tachypnea, or leukocytosis were present in 91.5% of this cohort, and 63.8% had at least 2 of these findings. Twenty alternate ICD-9s were identified, including non-CAP pulmonary disease (18%; 95% CI, 13-24), renal disease (16%; 95% CI, 13-19), other infections (9%; 95% CI, 7-11), cardiovascular diseases (3%; 95% CI, 2-4), and other miscellaneous diagnosis (28%; 95% CI, 25-31). Conclusions: Our data suggest that the ED diagnosis of CAP frequently differs from the discharge diagnosis. This may be due to the fact that a diagnosis of CAP relies on a combination of potentially nonspecific clinical and radiographic features. New diagnostic approaches and tools with better specificity are needed to improve ED diagnosis of CAP.

The efficacy and safety of the combination of medetomidine and ketamine was examined in order to establish an adequate chemical immobilization protocol in the Eurasian otter (Lutra lutra) for use during translocation projects in Spain. Thirty-eight Eurasian otters ranging in body mass from 3 to 8.7 kg (mean 5.3 kg) were successfully anesthetized on 82 occasions. The dosage of ketamine was 5.1 Ϯ 0.8 (3.4-6.6) mg/kg (mean Ϯ SD; range) combined with medetomidine at a dosage of 51 Ϯ 8 g/kg (34-66 g/kg). In most cases anaesthetic effect occurred within 3 min and the mean induction time was 5.5 Ϯ 3.2 min. The mean pulse rate was 95 beats/ min. The mean respiratory rate was 32 respirations/min while the relative oxyhemoglobin saturation was 93%. According to these results, this anesthetic protocol is considered safe and can be recommended in wild caught Eurasian otters for immobilization during translocation projects. It is safe, rapid and can be reversed when needed with atipamezole. However caution is required as heart depression resulting in bradychardia may occur.

Oxygenation measurements are widely used in patient care. However, most clinically available instruments currently consist of contact probes that only provide global monitoring of the patient (e.g., pulse oximetry probes) or local monitoring of small areas (e.g., spectroscopy-based probes). Visualization of oxygenation over large areas of tissue, without a priori knowledge of the location of defects, has the potential to improve patient management in many surgical and critical care applications. In this study, we present a clinically compatible multispectral spatial frequency domain imaging (SFDI) system optimized for surgical oxygenation imaging. This system was used to image tissue oxygenation over a large area (16×12 cm) and was validated during preclinical studies by comparing results obtained with an FDA-approved clinical oxygenation probe. Skin flap, bowel, and liver vascular occlusion experiments were performed on Yorkshire pigs and demonstrated that over the course of the experiment, relative changes in oxygen saturation measured using SFDI had an accuracy within 10% of those made using the FDA-approved device. Finally, the new SFDI system was translated to the clinic in a first-in-human pilot study that imaged skin flap oxygenation during reconstructive breast surgery. Overall, this study lays the foundation for clinical translation of endogenous contrast imaging using SFDI.

LTMS-S is a new wearable system for the monitoring of several physiological signals -including a twolead electrocardiogram (ECG) -and parameters, such as the heart rate, the breathing rate, the peripheral oxygen saturation (SpO2), the core body temperature (CBT), and the physical activity. All signals are measured using only three sensors embedded within a vest. The sensors are standalone with their own rechargeable battery, memory, wireless communication and with an autonomy exceeding 24 hours. This paper presents the results of the clinical validation of the LTMS-S system.

Motion and noise artifacts (MNA) are a serious obstacle in utilizing photoplethysmogram (PPG) signals for real-time monitoring of vital signs. We present a MNA detection method which can provide a clean vs. corrupted decision on each successive PPG segment. For motion artifact detection, we compute four time-domain parameters: (1) standard deviation of peak-to-peak intervals (2) standard deviation of peak-to-peak amplitudes (3) standard deviation of systolic and diastolic interval ratios, and (4) mean standard deviation of pulse shape. We have adopted a support vector machine (SVM) which takes these parameters from clean and corrupted PPG signals and builds a decision boundary to classify them. We apply several distinct features of the PPG data to enhance classification performance. The algorithm we developed was verified on PPG data segments recorded by simulation, laboratory-controlled and walking/ stair-climbing experiments, respectively, and we compared several well-established MNA detection methods to our proposed algorithm. All compared detection algorithms were evaluated in terms of motion artifact detection accuracy, heart rate (HR) error, and oxygen saturation (SpO 2) error. For laboratory controlled finger, forehead recorded PPG data and daily-activity movement data, our proposed algorithm gives 94.4, 93.4, and 93.7% accuracies, respectively. Significant reductions in HR and SpO 2 errors (2.3 bpm and 2.7%) were noted when the artifacts that were identified by SVM-MNA were removed from the original signal than without (17.3 bpm and 5.4%). The accuracy and error values of our proposed method were significantly higher and lower, respectively, than all other detection methods. Another advantage of our method is its ability to provide highly accurate onset and offset detection times of MNAs. This capability is important for an automated approach to signal reconstruction of only those data points that need to be reconstructed, which is the subject of the companion paper to this article. Finally, our MNA detection algorithm is realtime realizable as the computational speed on the 7-s PPG data segment was found to be only 7 ms with a Matlab code.

We designed this study to determine the effect of the menstrual cycle on the hemodynamic response to tracheal intubation (TI). Sixty-two ASA I women who were either in the follicular phase (group F, n ϭ 31) or luteal phase (group L, n ϭ 31) of their menstrual cycle were included in the study. Patients received propofol and rocuronium for intubation. Hemodynamic variables were recorded before administration of the IV anesthetic, as well as after TI. Rate pressure products were calculated. Groups were similar in terms of demographic data. Rate pressure products values at the first minute after TI were significantly increased in group L than were those in group F (P Ͻ 0.001). We conclude that the phase of the menstrual cycle is an important factor in the hemodynamic response

Coulange M, Barthelemy A, Hug F, Thierry AL, De Haro L. Reliability of new pulse CO-oximeter in victims of carbon monoxide poisoning. Undersea Hyperb Med 2008; 35(2):107-111. Study objective: The purpose of this study was to evaluate the reliability of noninvasive real-time measurement of carboxyhemoglobin (COHb) using a pulse CO-oximeter in victims of carbon monoxide poisoning (COP). Methods: During the 7-month study period, pulse CO-oximetry was measured on patients admitted to the emergency department (ED) for suspected COP. Each patient included in the study underwent concomitant assessment of COHb by blood sampling and noninvasive pulse CO-oximetry (SpCO). Results: Twelve non-smoker patients were included. Mean age was 40 ± 17 years. No difference was found between the two COHb assessment techniques (p>0.05). Analysis using the Bland and Altman procedure suggested good alignment of the two techniques with a slight bias (i.e. -1.5%) indicating slight overestimation by the pulse CO-oximeter. Analysis using the Passing and Bablok statistical protocol further documented the reliability of the two methods. Conclusion: This study documents the precision of the correlation between readings obtained with the noninvasive pulse CO-oximeter and COHb measurements from blood samples. This preliminary result demonstrates that this simple rapid noninvasive technology could be useful before and after arrival at the ED.

58 patients who underwent on-pump coronary artery bypass graft surgery were evaluated for changes in regional cerebral oxygen saturation (rSO2) measured by near infrared spectroscopy (NIRS). If rSO2 during the operation fell to more than 20% under the baseline, standardized interventions were undertaken to maintain rSO2. Despite those interventions, in some cases we observed inability to maintain rSO2 above this threshold. Therefore we divided patients in two subgroups: 1. without prolonged rSO2 desaturation; 2. with prolonged rSO2 desaturation (area under the curve >150 min% for rSO2<20% of baseline and >50 min% for rSO2<50% of absolute value). The data were analyzed to determine whether there were major differences in outcome of these two groups. 18 out of 58 patients (31%) had prolonged rSO2 desaturation during operation. There was significantly higher number of diabetic patients in group with prolonged rSO2 desaturation (p=0.02). Intraoperative data revealed signific...

Inhaled nitric oxide (NO) is used as a therapy of pulmonary hypertension in children after cardiac surgery. Hemoglobin binds to NO with great affinity and forms methemoglobin by oxidation in the erythrocyte. Once produced, methemoglobin is unable to transport and unload oxygen in the tissues. The amount of available hemoglobin in the body for oxygen transport is thereby reduced. Anemia, acidosis, respiratory compromise and cardiac disease may render patients more susceptible than expected for a given methemoglobin level. The goal of the present study was to review the cumulative effect of inhaled NO on methemoglobin formation in critically ill children. We therefore looked for methemoglobin levels in children with congenital heart disease after cardiac surgery who were treated with inhaled NO in a range of 5-40 ppm. We retrospectively reviewed the medical charts of 38 children with congenital heart disease after cardiac surgery. We extracted demographic data and physiological measur...

Technology development in wearable sensors and biosignal processing has made it possible to detect human stress from the physiological features. However, the intersubject difference in stress responses presents a major challenge for reliable and accurate stress estimation. This research proposes a novel cluster-based analysis method to measure perceived stress using physiological signals, which accounts for the intersubject differences. The physiological data are collected when human subjects undergo a series of task-rest cycles, incurring varying levels of stress that is indicated by an index of the State Trait Anxiety Inventory. Next, a quantitative measurement of stress is developed by analyzing the physiological features in two steps: 1) a k -means clustering process to divide subjects into different categories (clusters), and 2) cluster-wise stress evaluation using the general regression neural network. Experimental results show a significant improvement in evaluation accuracy ...

Secondary brain injury is associated with a reduction in cerebral blood jlow, oxygenation and perfusion related to hypotension, hypoxemia and raised intracranial pressure. This has been confirmed on autopsy and is associated with a higher mortality rate, as supported by many studies I-". The primary goal of nursing management in severe head trauma is to maintain adequate cerebral perfusion and improve cerebral blood flow in order to prevent cerebral ischaemia and secondary injury to the brain.

what information is important and how it should be displayed and analyzed. The Neurocritical Care Society in collaboration with the European Society of Intensive Care Medicine, the Society for Critical Care Medicine, and the Latin America Brain Injury Consortium organized an international, multidisciplinary consensus conference to begin to address these needs. International experts from neurosurgery, neurocritical care, neurology, critical care, neuroanesthesiology, nursing, pharmacy, and informatics were recruited on the basis of their research, publication record, and expertise. They undertook a systematic literature review to develop recommendations about specific topics on physiologic processes important to the care of patients with disorders that require neurocritical care. This review does not make recommendations about treatment, imaging, and intraoperative monitoring. A multidisciplinary jury, selected for their expertise in clinical investigation and development of practice guidelines, guided this process. The GRADE system was used to develop recommendations based on literature review, discussion, integrating the literature with the participants' collective experience, and critical review by an impartial jury. Emphasis was placed on the principle that recommendations should be based on both data quality and on trade-offs and translation into clinical practice. Strong consideration was given to providing pragmatic guidance and recommendations for bedside neuromonitoring, even in the absence of high quality data.

The lowest values of pulse pressure (dPP) and peripheral temperature (Tp) associated with reliable readings from three different pulse oximeters (Biox Ohmeda 3700, Datex Satlite, and Nellcor N-200) were assessed, along with the ability of the pulse oximeters to work immediately before and after total cardiopulmonary bypass (CPB). The lowest mean dPP with a reliable 0, saturation reading was 13 mm Hg

Pulse oximeters are known to be inaccurate in the presence of elevated concentrations of carboxyhemoglobin and methemoglobin. This paper attempts to alleviate some of the confusion that exists between fractional and functional saturation, and to clarify the comparison of each with SpO2. A series of theoretical relationships between pulse oximeter reading (SpO2) and actual oxygen saturation (both fractional and functional) is derived using simple absorption theory. The theoretical relationships are checked using an experimental in vitro test system. This consists of a blood circuit containing a model finger, capable of simulating the pulsatile transmission signals through a real finger. Theoretical predictions and experimental results are compared and are found to agree well in the presence of carboxyhemoglobin, but less well with methemoglobin. Possible reasons are discussed.

OBJECTIVE: The purposes of the study were to: (1) describe the aggregate strength of the relationship of arterial oxygen saturation as measured by pulse oximetry with the standard of arterial blood gas analysis as measured by co-oximetry, (2) examine how various factors affect this relationship, and (3) describe an aggregate estimate of the bias and precision between oxygen saturation as measured by pulse oximetry and the standard in vitro measures.

Version 2.2 of the American Academy of Sleep Medicine (AASM) Manual for the Scoring of Sleep and Associated Events was released on July 1, 2015. The Scoring Manual Editorial Board (previously the Scoring Manual Committee) would like to call attention to the most important changes. As discussed below, there are two new major sections providing rules for the staging of infant sleep and scoring respiratory events in home sleep apnea testing (HSAT) studies. The new sections were approved by the AASM Board of Directors to fill two obvious gaps in the Scoring Manual. The Scoring Manual Editorial Board would like to emphasize that any changes proposed in the manual are done so after long deliberation and consultation with area content experts.

Background To avoid ischemic hand complications, the percutaneous transradial approach is only performed in patients with patent hand collateral arteries, which is usually evaluated with the modified Allen's test (MAT). This qualitative test measures the time needed for maximal palmar blush after release of the ulnar artery compression with occlusive pressure of the radial artery. The objectives were to evaluate the patency of the hand collateral arteries and to compare MAT with combined plethysmography (PL) and pulse oximetry (OX) tests before the percutaneous transradial approach.

Background: The pulse oximeter perfusion index (PI) has been used to indicate sympathectomy-induced vasodilatation. We hypothesized that pulse oximeter PI provides an earlier and clearer indication of sympathectomy following epidural anesthesia than skin temperature and arterial pressure.Methods: Forty patients received lumbar epidural catheters. Patients were randomized to receive either 10 ml 0.5% bupivacaine or 10 ml 0.25% bupivacaine. PI in the toe, mean arterial pressure (MAP) and toe temperature were all assessed at baseline and at 5, 10 and 20 min following epidural anesthesia. The effect of epidural anesthesia over time was assessed by repeated measures analysis of variance. Additionally, we defined clinically evident sympathectomy criteria (a 100% increase in the PI, a 15% decrease in MAP and a 1 °C increase in toe temperature). The numbers of patients demonstrating these changes for each test were compared using the McNemar test for each time point.Results: Twenty-nine subjects had photoplethysmography signals that met a priori signal quality criteria for analysis. By 20 min, PI increased by 326%, compared with a 10% decrease and a 3% increase in MAP and toe temperature, respectively. For PI 15/29, 26/29 and 29/29 of the subjects met the sympathectomy criteria at 5, 10 and 20 min, respectively, compared with 4/29, 6/29 and 18/29 for MAP changes and 3/29, 8/29 and 14/29 for toe temperature changes.Conclusions: PI was an earlier, clearer and more sensitive indicator of the development of epidural-induced sympathectomy than either skin temperature or MAP.

Die Überwachung der zerebralen Sauerstoffsättigung mithilfe der Nahinfrarotspektroskopie erlaubt nichtinvasiv eine Abschätzung des zerebralen Verhältnisses von Sauerstoffangebot und -bedarf. Eine zunehmende Zahl an Untersuchungen deutet darauf hin, dass dieses Verfahren darüber hinaus -unter Berücksichtigung methodenimmanenter Limitationen -auch zur Evaluation der systemischen Perfusion herangezogen werden kann. Obwohl die Anästhesie erheblichen Einfluss auf zerebrale Funktionen nimmt, Patienten immer älter werden und in höherem Alter neurologische Komplikationen wie postoperatives Delir oder kognitive Funktionsstörungen nach operativen Eingriffen deutlich zunehmen [1], gehört die perioperative Überwachung des Gehirns vielerorts nicht zur anästhesiologischen Routine. Mit der zerebralen Oximetrie steht ein nichtinvasives Messverfahren der intraoperativen Oxygenierung zur Verfügung, das sich in klinischen Bereichen mit besonderer Gefährdung der zerebralen Integrität wie der Herz-und Gefäßchirurgie zunehmend etabliert hat [2, 3, 4].

Peripheral perfusion is often poor and barely pulsatile in patients undergoing prolonged major surgery. Hence, the arterial blood oxygen saturation (SpO 2) readings from commercial finger pulse oximeters can become unreliable or cease when they are most needed. To overcome this limitation, the esophagus has been investigated as an alternative measurement site, as perfusion may be preferentially preserved centrally. A reflectance esophageal pulse oximeter probe, and a processing system implemented in LabVIEW were developed. The system was evaluated in clinical measurements on 49 cardiothoracic surgery patients. The SpO 2 values from the esophagus were in good agreement with arterial blood oxygen saturation (SaO 2) values obtained from blood gas analysis and CO-oximetry. The means (SD) of the differences between the esophageal SpO 2 and SaO 2 results from blood gas analysis and CO-oximetry were 0.02 0.88% and 0.73 0.72%, respectively. In five (10.2%) of the patients, the finger pulse oximeter failed for at least 10 min while the esophageal SpO 2 readings remained reliable. The results confirm that the esophagus may be used as an alternative monitoring site for pulse oximetry even in patients with compromised peripheral perfusion.

Background: Bright constant light levels in the NICU may have negative effects on the growth and development of preterm infants Objective: The aim of this study is to evaluate the benefits of an alternating light/dark cycle in the NICU on weight gain and early discharge from the therapy in premature infants. Patients and methods: A randomized interventional study was designed comparing infants in the NICU of Hospital Juarez de México, exposed from birth either to an LD environment (LD, n = 19) or to the traditional continuous light (LL, n = 19). The LD condition was achieved by placing individual removable helmets over the infant's heads. Body weight gain was analyzed, as the main indicator of stability and the main criteria for discharge in preterm infants born at 31.73 ± 0.31 week gestational age. Results: Infants maintained in an LD cycle gained weight faster than infants in LL and therefore attained a shorter hospital stay, (34.37 ± 3.12 vs 51.11 ± 5.29 days; P N 0.01). Also, LD infants exhibited improved oxygen saturation and developed a daily melatonin rhythm. Conclusions: These findings provide a convenient alternative for establishing an LD environment for preterm healthy newborns in the NICU and confirm the beneficial effects of an alternating LD cycle for growth and weight gain and for earlier discharge time. Here we provide an easy and practical alternative to implement light/dark conditions in the NICU.

what information is important and how it should be displayed and analyzed. The Neurocritical Care Society in collaboration with the European Society of Intensive Care Medicine, the Society for Critical Care Medicine, and the Latin America Brain Injury Consortium organized an international, multidisciplinary consensus conference to begin to address these needs. International experts from neurosurgery, neurocritical care, neurology, critical care, neuroanesthesiology, nursing, pharmacy, and informatics were recruited on the basis of their research, publication record, and expertise. They undertook a systematic literature review to develop recommendations about specific topics on physiologic processes important to the care of patients with disorders that require neurocritical care. This review does not make recommendations about treatment, imaging, and intraoperative monitoring. A multidisciplinary jury, selected for their expertise in clinical investigation and development of practice guidelines, guided this process. The GRADE system was used to develop recommendations based on literature review, discussion, integrating the literature with the participants' collective experience, and critical review by an impartial jury. Emphasis was placed on the principle that recommendations should be based on both data quality and on trade-offs and translation into clinical practice. Strong consideration was given to providing pragmatic guidance and recommendations for bedside neuromonitoring, even in the absence of high quality data.

OBJECTIVE To review the published, peer-reviewed studies to date on use of the new-generation pulse oximeters, which are manufactured with algorithms to filter out patients' body motions, and describe the application of new-generation pulse oximetry in clinical practice in critical care. • METHODS MEDLINE was used to locate appropriate articles on pulse oximetry for the years 1995 to 2003. Each article was examined for scientific merit, content, and applicability to clinical practice. • RESULTS A total of 17 relevant articles on the clinical performance of the new-generation pulse oximeters were reviewed, and the data were organized into a table. • CONCLUSIONS The combination of studies done in both clinical and laboratory settings did not provide any strong and convincing evidence that the performance of any single new-generation device was superior to that of any other new-generation device. However, the clinical performance of all the newgeneration pulse oximetry devices was better than that of earlier devices.

Pulse oximetry provides a simple, non-invasive approximation of arterial oxygenation in a wide variety of clinical settings including emergency and criticalcare medicine, hospital-based and ambulatory care, perioperative monitoring, inpatient and outpatient settings, and for specific diagnostic applications. Pulse oximetry is of utility in perinatal, paediatric, adult and geriatric populations but may require use of agespecific sensors in these groups. It plays a role in the monitoring and treatment of respiratory dysfunction by detecting hypoxaemia and is effective in guiding oxygen therapy in both adult and paediatric populations. Pulse oximetry does not provide information about the adequacy of ventilation or about precise arterial oxygenation, particularly when arterial oxygen levels are very high or very low. Arterial blood gas analysis is the gold standard in these settings. Pulse oximetry may be inaccurate as a marker of oxygenation in the presence of dyshaemoglobinaemias such as carbon monoxide poisoning or methaemoglobinaemia where arterial oxygen saturation values will be overestimated. Technical considerations such as sensor position, signal averaging time and data sampling rates may influence clinical interpretation of pulse oximetry readings.

The current diversity of opinions in endodontic diagnosis has been a source of interest and academic debate by clinicians and researchers. Currently, no single pulp testing technique can reliably diagnose all pulpal conditions neither it has been proven to be superior in all aspects. Despite improvements of various aspects of this process, there are no historically dramatic changes, or consensus for pulpal status in health or disease in addition to a lack of relative systematic reviews. In this review, the past, present and future most debated and critically questioned issues of endodontic diagnosis are discussed. The aim of this review is to provide insights in future diagnostic modalities and areas for further study in endodontic practice pertinent to diagnosis.