Pulse oximeters measure the arterial oxygenation by determining the color of the blood between a light source and a photodetector. The light source consists of two light-emitting diodes (LEDs) that emit light at known wave lengths, 660 nm red light and 940 nm infrared light. The ratio of pulse-added red absorbance at 660 nm to pulse-added infrared absorbance at 940 nm is used to generate the oximeter's estimate of arterial saturation (SpO2). Pulse oximeters can determine the concentration of only two hemoglobins, reduced (HHb) and oxyhemoglobin (HbO2), so they can't distinguish the dyshemoglobins (methemoglobin, carboxyhemoglobin) which have light absorbances similar to that of HHb or HbO2. If the concentration of dyshemoglobin is above the normal range, pulse oximeters would give erroneous SpO2 readings. We experienced a case which showed a low SpO2 reading but had normal ABGA findings due to unsuspected methemoglobinemia.
Methemoglobinemia* ; Oxygen ; Oxyhemoglobins ; Reading ; Reference Values

BACKGROUND: Plasma hemoglobin has usually been determined by the spectrophotometric method of Harboe. This method is known to show interference by bilirubin and turbidity, although the method is easy. In order to correct the spurious increase of plasma hemoglobin concentration caused by hyper-bilirubinemia, we compared plasma hemoglobin assays by using various spectrophotometry methods and tried to select the method of minimal interference. METHODS: We performed five plasma hemoglobin assays based on spectrophotometry (Harboe, Noe, Kahn, Fairbanks 1, and Fairbanks 2) and three bilirubin assays (Fairbanks 1, Fairbanks 2, and bilirubin oxidase) on 100 patients without hemolysis and lipemia. RESULTS: The method of Kahn, et al. and the method 2 of Fairbanks, et al. of the plasma hemoglobinassay seemed to minimally interfere with the bilirubin. Only plasma oxyhemoglobin was measured by the method of Kahn, et al .; on the other hand, plasma hemoglobin and bilirubin could be measured one at a time by the method 2 of Fairbanks, et al. Method 1 of Fairbanks, et al. seemed to interfere extremely with bilirubin. CONCLUSIONS: Method 2 of Fairbanks, et al. is the first choice for the plasma hemoglobin assay considering the interference with bilirubin.
Bilirubin ; Hand ; Hemolysis ; Humans ; Hyperbilirubinemia* ; Hyperlipidemias ; Oxyhemoglobins ; Plasma* ; Spectrophotometry

OBJECTIVE: To report successful cases of extubation from invasive mechanical ventilation at our institution using pulmonary rehabilitation consisting of noninvasive ventilation (NIV) in neuromuscular patients with experience of reintubation. METHODS: Patients who experienced extubation failure via the conventional weaning strategy but afterwards had extubation success via NIV were studied retrospectively. Continuous end-tidal CO₂ (ETCO₂) and pulse oxyhemoglobin saturation (SpO₂) monitoring were performed. Extubation success was defined as a state not requiring invasive mechanical ventilation via endotracheal tube or tracheotomy during a period of at least 5 days. RESULTS: A total of 18 patients with ventilatory failure who initially experienced extubation failure were finally placed under part-time NIV after extubation. No patient had any serious or long-term adverse effect from NIV, and all patients left the hospital alive. CONCLUSION: NIV may promote successful weaning in neuromuscular patients with experience of reintubation.
Humans ; Neuromuscular Diseases* ; Noninvasive Ventilation* ; Oxyhemoglobins ; Rehabilitation ; Respiration, Artificial ; Retrospective Studies ; Tracheotomy ; Weaning*

The reactions of cerebral pial vessels following the injection of normal saline(0.05cc, at 37 degrees C, pH7.4) and autogenous hemolytic blood(0.05cc, 0.1cc 0.2cc) into the cisterna magna of rabbits were tested in vivo. This experiment was performed in order to observe the effect of intravenous nimodipine(30 microgram/kg) injection at the maximally constricted time of the pial vessels, about 6 hours after intracisternal injection of autogenous hemolytic blood. The diameter changes of the pial vessels were measured under operating microscope through a cranial window on craniectomized area. Pial vessels were not significantly changed after an intracisternal injection of normal saline. But after intracisternal injection of autogenous hemolytic blood(0.05cc, 0.1cc, 0.2cc), pial vessels were maximally constricted at 6 hours and the constriction was continued during the experiments. Percentile constriction was increased as the amount of subarachnoid hemolytic blood increased. According to the results, pial vessels, especially small pial artery, were constricted by autogenous hemolytic blood containing oxyhemoglobin. Nimodipine, calcium antagonist, showed dilating effect on vasospasm after experimental subarachnoid hemorrhage with autogenous hemolytic blood in rabbits.
Administration, Intravenous* ; Arteries ; Calcium ; Cisterna Magna* ; Constriction ; Nimodipine* ; Oxyhemoglobins ; Rabbits* ; Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE: Periodic limb movements (PLM) during sleep (PLMS) are associated with cortical and cardiovascular activation. Changes in cerebral hemodynamics caused by cortical activity can be measured using near-infrared spectroscopy (NIRS). We investigated oscillatory components of cerebral hemodynamics during PLM and different sleep stages in restless legs syndrome (RLS) patients with PLMS. METHODS: Four female RLS patients with PLMS, and four age- and sex-matched normal controls were included. PLM and sleep stages were scored using polysomnography, while the spontaneous cerebral hemodynamics was measured by NIRS. The phase and amplitude of the cerebral oxyhemoglobin concentration [HbO] and the deoxyhemoglobin concentration [Hb] low-frequency oscillations (LFOs) were evaluated during each sleep stage [waking, light sleep (LS; stages N1 and N2), slow-wave sleep (stage N3), and rapid eye movement (REM) sleep]. In RLS patients with PLMS, the cerebral hemodynamics during LS was divided into LS with and without PLM. RESULTS: The cerebral hemodynamics activity varied among the different sleep stages. There were changes in phase differences between [HbO] and [Hb] LFOs during the different sleep stages in the normal controls but not in the RLS patients with PLMS. The [HbO] and [Hb] LFO amplitudes were higher in the patient group than in controls during both LS with PLM and REM sleep. CONCLUSIONS: The present study has demonstrated the presence of cerebral hemodynamics disturbances in RLS patients with PLMS, which may contribute to an increased risk of cerebrovascular events.
Extremities* ; Female ; Hemodynamics* ; Humans ; Oxyhemoglobins ; Polysomnography ; Restless Legs Syndrome* ; Sleep Stages ; Sleep, REM ; Spectroscopy, Near-Infrared*

Postoperative brain damage is one of most serious complications of cardiopulmonary bypass (CPB). To prevent brain damage during CPB, adequate cerebral perfusion for cerebral oxygen demand should be maintained. This study monitored jugular venous oxyhemoglobin saturation (SjO₂), which reflects the overall balance of cerebral oxygen supply and demand, intermittently in 10 patients undergoing cardiac surgery. At the initiation of CPB, in spite of a significant decrease in mean arterial pressure, SjO₂ did not change, and it was stable during the hypothermic period of CPB. But a significan reduction in SjO₂ was observed during the rewarming period, and SjO₂ had an inverse linear correlation with esophageal temperature. Furthermore, the percent decrease of SjO₂ was related to rewarming speed. Therefore, therapeutic approaches for SjO₂ desaturation include slower rewarming, increasing cerebral blood flow, decreasing the cerebral metabolic rate for oxygen, increasing oxygen content, and increasing perfusion flow rate.
Arterial Pressure ; Brain ; Cardiopulmonary Bypass ; Cerebrovascular Circulation ; Humans ; Oxygen ; Oxyhemoglobins* ; Perfusion ; Rewarming ; Thoracic Surgery

For obtaining P50 in mongrel dogs at normal body temperature (37degrees C), pH(7.4) and PaCO2 (40 mmHg), we performed arterial blood gas analysis in 14 mongrel dogs by using ABL 30 blood gas analyzer ( Radiometer, Copenhagen, Denmark) after inhalation of various concentration of oxygen. The oxyhemoglobin dissociation curve was made by plotting of arterial O2 saturation against each PaO2, and P50 was obtained by using linear regression equation. The result shows that P50 in mongrel dogs is 28.5+/-0.8 mmHg (mean+/-DS).
Animals ; Blood Gas Analysis ; Body Temperature ; Dogs* ; Inhalation ; Linear Models ; Oxygen ; Oxyhemoglobins

For obtaining P50 in mongrel dogs at normal body temperature (37degrees C), pH(7.4) and PaCO2 (40 mmHg), we performed arterial blood gas analysis in 14 mongrel dogs by using ABL 30 blood gas analyzer ( Radiometer, Copenhagen, Denmark) after inhalation of various concentration of oxygen. The oxyhemoglobin dissociation curve was made by plotting of arterial O2 saturation against each PaO2, and P50 was obtained by using linear regression equation. The result shows that P50 in mongrel dogs is 28.5+/-0.8 mmHg (mean+/-DS).
Animals ; Blood Gas Analysis ; Body Temperature ; Dogs* ; Inhalation ; Linear Models ; Oxygen ; Oxyhemoglobins

Aluminum phosphide is commonly used as a rodenticidal agent in agricultural workplaces. However, reported cases of aluminum phosphide poisoning in Korea are rare. Upon contact with moisture in the air, aluminum phosphide releases highly toxic phosphine gas (PH3). PH3 is readily absorbed through lung epithelium and into the bloodstream. Phosphine may cause denaturing of oxyhemoglobin and enzymes important to respiration and metabolism, and also may effect cellular membranes. There are numerous complications associated with acute aluminum phosphide poisoning including gastrointestinal, respiratory, and cardiac toxicities. We report the case of a 46-year-old man who suffered from respiratory and cardiac toxicities after unintentional aluminum phosphide exposure. More intensive education for prevention is recommended.
Aluminum ; Aluminum Compounds ; Epithelium ; Humans ; Korea ; Lung ; Membranes ; Middle Aged ; Oxyhemoglobins ; Phosphines ; Respiration

The paper first analyses the principles of measurement of the two-wave oximeter and their limitations in technology. We propose to filter off motion interference from pulse oximeter signal using an algorithm based on the Beer-Lambert law that requires a three-wave probe (660 nm, 850 nm, and 940 nm). Based on the new algorithm, this paper describes the design principle of the circuitry and the software flowchart. Also, we study the calibration method of the pulse oximeter sensor and discuss the results in this paper.
Calibration ; standards ; Equipment Design ; Humans ; Oximetry ; instrumentation ; Oxygen ; metabolism ; Oxyhemoglobins ; analysis