OBJECTIVETo investigate the relationship between blood nitrogen monoxide(NO) and PaO2 or PaCO2 levels in patients with severe and moderate acute carbon monoxide poisoning.

METHODThe blood levels of NO in patients with severe and moderate acute carbon monoxide poisoning was assayed with nitrate reductase method, and its correlation with the blood levels of PaO2 and PaCO2 was analyzed.

RESULTSThe blood level of NO in patients with severe and moderate acute carbon monoxide poisoning were (36.6 +/- 9.9) and (35.7 +/- 10.7) mumol/L respectively, significantly lower than that of control group[(64.9 +/- 14.3) mumol/L, P < 0.01], but there was no significant difference between moderate and severe patients(P > 0.05). The analysis of linear correlation showed that there was significant positive correlation between NO and PaO2 but not PaCO2.

CONCLUSIONAnoxia of patients with acute carbon monoxide poisoning may be an important cause to reduce NO level in blood. This study provides the basis for low NO concentration inhalation in treatments of acute carbon monoxide poisoning.

Acute Disease ; Carbon Dioxide ; blood ; Carbon Monoxide Poisoning ; blood ; Humans ; Nitric Oxide ; blood ; Oxygen ; blood

The recording of middle cerebral artery (MCA) flow veloeity by transcrsnisl Doppler technique offers s new, noninvasive, and continuous technique for studies of cerebral circu lation. The influence of changes in PaCO2 on MCA flow velocity were observed during hypothermic cardiopulmonary bypass(CPB) surgery by means of transcranial Doppler tech- niques. In ten patients who were undergoing hypothermic CPB surgery, the right MCA flow velocity was measured before initiation of CPB(prebypass period) and after the termination of CPB (postbypass period). During steady state CPB(constant hematocrit, constant temperature, and constant total pump flow), baseline MCA flow velocity(CPB I period) was measured and then repeated after specific alteration of PaCO2 achieved by changing of fresh gas flow to oxygenetors(CPB II period). And carbon dioxide reactivity defined as percent change of MCA flow velocity per mmHg changes in PaCO2 was observed during stable hypothermic CPB. MCA flow veocity showed no statistical difference between the prebypass value(56.9+/-13.5 cm/sec) and the postbypass value(64.7+/-29.7 cm/sec). PaCO2 of 20.5+/-2.5 mmHg was associated with MCA flow velocity of 25.2+/-10.1 cm/sec in the CPB I period while PaCO2 of 27.1+/-3.5 mmHg was associated with MCA flow velocity of 35.3+/-12.9 cm/sec. MCA flow velocity carbon dioxide reactivity during steady state hypothermie CPB was 6.68+/-2.26 %/ mmHg. These results have demonstrated that the response of MCA flow velocity to changes in PaO2 was well maintained during hypothermic CPB and the use of transcrsnial Doppler would give valuable results in the study of cerebral circulation during hypothermic CPB.
Blood Flow Velocity* ; Carbon Dioxide* ; Carbon* ; Cardiopulmonary Bypass* ; Hematocrit ; Humans ; Middle Cerebral Artery

Intravenous membrane oxygenator (IVOX), an artificial lung usually located in vena caval system, can provide extra oxygen outside the lung for patients suffering from respiratory failure. However, gas exchange areas of IVOX are limited because of confined space in caval system. The increase of the diameter of IVOX may impede the return of venous blood to heart, and result in serious low blood pressure. Thus, it is important to increase the efficiency of IVOX by reducing the diffusive resistance of boundary layers. In the present study, the hollow member fiber of IVOX was weaved in braids; we tested the oxygen transfer efficiency and blood flow resistance of this IVOX in vitro. The results showed that the total transferred oxygen, the oxygen transfer rate and blood resistance increased with the increase of blood flow. The oxygen volume transferred by the IVOX and the oxygen transfer rate were (55.97 +/- 0.51) ml/min and (127.19 +/- 0.66) ml/(min x m)2 respectively at the blood flow of 5 L/min and hemoglobin of 120 g/L. They were significantly higher than those at 4 L/min and 3.5 L/min, respectively. The pressure drop also increased from (11.87 +/- 1.57) cmH2O at 3.5 L/min of blood flow to (18.53 +/- 0.99) cmH2O at 4 L/min and 19.77+/- 0.51 cmH2O at 5 L/min. However, they are safe to the patients (< 20 cmH2O). These results suggest that this braid type of IVOX can safely provide 20%-30% oxygen outside the lung for an adult patient.
Animals ; Carbon Dioxide ; blood ; Hemoglobin A ; analysis ; Oxygen ; blood ; Oxygenators, Membrane ; classification ; Regional Blood Flow ; Swine

In order to simplify the technique of extracorporeal membrane oxygenation (ECMO) and apply extracorporeal life support ( ECLS) broadly for assisting the treatment of severe respiratory failure patients, we have developed a blood-gas exchanger (BGE) with the characteristics of small volume and simple structure. The exchange between blood and gas of BGE adopts cross-flowing model; blood flows along the outer hollow fiber and gas flows in the inner hollow fiber with the reverse direction of blood flowing. The interface of blood flow in and out was designed as the internal spiral, and the caliber of BGE is matched with the blood interface of dialysis. Thus it may successfully make single-use spiral connectors link up mutually in the extracorporeal blood circulation of dialysis, may help clinical operations become safe, convenient and easily-controlled, and may simplify the technique of EGMO.
Carbon Dioxide ; blood ; Equipment Design ; Extracorporeal Membrane Oxygenation ; instrumentation ; Humans ; Life Support Care ; instrumentation ; Oxygen ; blood

Blood Circulation ; Carbon Dioxide ; blood ; Humans ; Medicine, Chinese Traditional ; Meridians ; Qi ; Science

The key to the treatment of septic shock is to provide adequate oxygen supply and improve tissue perfusion. Lactate and central venous oxygen saturation (ScvO) are commonly used as the indices of oxygen metabolism, but tissue hypoxia may still exist even when lactate and ScvOare within the normal range. Arteriovenous difference in carbon dioxide partial pressure (COgap) can accurately reflect oxygen delivery when ScvOis in the normal range. This article reviews the advantages and shortages of lactate, lactate clearance rate, ScvO, and COgap in evaluating tissue hypoxia, in order to provide a reference for treatment and severity evaluation of septic shock.
Carbon Dioxide ; blood ; Humans ; Lactic Acid ; metabolism ; Metabolic Clearance Rate ; Oxygen ; blood ; Shock, Septic ; metabolism

PURPOSE: To determine the concordance of transcutaneous CO2 (PtcCO2) versus arterial CO2 (PaCO2), end-tidal CO2 (PetCO2) versus PaCO2, and transcutaneous O2 (PtcO2) versus arterial O2 (PaCO2) among healthy adult volunteers, and to determine the normal values of the PtcCO2/PtcO2 and PtcO2/PaO2 that will be used as early signs of shock or as prognostic factors for critically ill patients. METHODS: We measured the PtcO2, PtcCO2, PetCO2, PaO2, and PaCO2 from 11 healthy volunteers while breathing room air or O2 at a flow rate of 6 L/min via nasal cannula. The PtcO2 and PtcCO2 were measured using a Radiometer's transcutaneous sensor that interfaced with the Solar 8000 patient monitor system. The PetCO2 was measured using a side stream capnometer that sampled air from a nasal catheter. The PaO2 and PaCO2 were measured from arterial blood samples. The concordances of the PtcCO2 versus the PaCO2, the PtcO2 versus the PaO2, and the PetCO2 versus the PaCO2 were analyzed using a Bland-Altman plot. We defined the normal values of the P(a-tc)CO2, PtcO2/PaO2, and PtcCO2/PtcO2. RESULTS: Twenty-two pairs of the PtcCO2 versus PaCO2, PtcO2 versus PaO2, and PetCO2 versus PaCO2 were obtained. The mean (+/-SD) values of the P(a-tc)CO2, P(atc) O2, and P(a-et)CO2 were 0(+/-2.2) mmHg, 35.4(+/-24.1) mmHg, and 1.4(+/-1.3) mmHg, respectively (p=0.947, p<0.001, and p<0.001 by paired t-test, respectively). The P(a-tc)CO2 and P(a-et)CO2 showed a high concordance of 95.5% within a range of +/-4 mmHg. The median (25~75%) values of the PtcCO2/PtcO2 and PtcO2/PaO2 at room air were 54.8%(46.8%~62.7%), respectively. CONCLUSION: The PtcCO2 and PetCO2 had a reliable concordance with the PaCO2. However, the PtcO2 was discordant with the PaO2 and this discordance was increased when inspiring O2. Therefore, the absolute values of the PtcO2 cannot be used as a surrogate measurement of the PaO2. However, because the O2 supply did not increase the PtcCO2, but rather the PtcO2, we can use the trend in the change in the PtcCO2/PtcO2 or PtcO2/PaO2 in shock patients.
Adult ; Blood Gas Monitoring, Transcutaneous ; Carbon ; Carbon Dioxide ; Catheters ; Critical Illness ; Humans ; Organothiophosphorus Compounds ; Oxygen ; Reference Values ; Respiration ; Rivers ; Shock

BACKGROUND: CO laser emiis energy in the mid portion of the infrared spectrum at a wavelengt,h of 10,600nm. The CO laser is the workhorse laser in the treatment of cuianeous disease. With water as the chromophore(light-absorbing compound), CO laser light is highy absorbed in biologic tissue. Human body tissue comprises between 75% to 90% of water. The CO laser is superficially absorbed by tissue water, with little scatter, limiting penetration into the skin to less than 0.1 mm. The beam can be delivered with a large spot size and low power density(defocus mode) or focused tightly with great power density(focused mode). AS A RESULT: the CO laser may be used both to vaporize and to cut tissue while coagulating blood vessels, providing a relatively bloodless su gical field. OBJECTIVE: The purpose of this study was to evaluate the therapeutie effect of the CO laser on benign cutaneous tumors. MEHTODS: 114 cases of benign cutaneous tumors treated with the CO laser between October 1987 and September 1992 were subjected to detailed analysis, The CO later is Pizer Laser system(U.S.A., Ca) Model 20-C CO. The laser produces power output that ranges from 0 to 25 W of continuous wave. Spot size is variable, between 0.3mm and 2mm. RESULTS: 1. Angiofibromas and seborcheic keratoses showed very good response(95.3%, 92.8% ). 2. Syringomas showed a good esponse(82.8%). 3. Epidermal nevus and trichovpitheliomas showed a fair response(58.5%, 60%). 4. There were hypertrophic scars(10.5%) and transient hypopigmentation. CONCLUSION: The Co laser was a very effective modality for the treatment of benign cutaneous tumors such as angiofibromas, seborrheic keratosis and syringomas.
Angiofibroma ; Blood Vessels ; Carbon Dioxide* ; Carbon* ; Human Body ; Hypopigmentation ; Keratosis ; Keratosis, Seborrheic ; Lasers, Gas* ; Nevus ; Skin ; Syringoma ; Water

BACKGROUND: The reduction is cerebral blood flow (CBF) caused by hypocapnia is an important element of anesthetic techniques for neurosurgery as well as for nonneurologic surgery in patients with reduced intracranial compliance. Accordingly, the impact of anesthetic agents on the CO2 responsiveness of the cerebral circulation has important implications with regard to anesthetic selection. The purpose of this study was to investigate the effects of isoflurane-N2O and propofol-N2O anesthesia on the CBF response to changes in end-tidal CO2 in healthy patients. METHODS: 19 healthy patients with nonneurological operation were selected. In group 1, anesthesia was induced with thiopental sodium 4 mg/kg, fentanyl 1 g/kg, succinylcholine 1~1.5 mg/kg and was maintained with isoflurane 0.5~1.5 vol%. In group 2, anesthesia was induced with propofol 2~2.5 mg/kg, fentanyl 1 g/kg, succinylcholine 1~1.5 mg/kg and was maintained with a propofol infusion of 10 mg/kg/h for 10 min and then 8 mg/kg/h for 10 min and then was reduced 3~6 mg/kg/h of the remainder of the study. All patients were ventilated with N2O in O2 (FIO2 0.5) and measured end-tidal CO2 (PETCO2). Mean blood flow velocity of middle cerebral artery was measured using transcranial Doppler in PETCO2 45, 40, 35, 30, 25, 20 mmHg. RESULT: CO2 reactivity of MCA flow velocity during isoflurane-N2O and propofol-N2O anesthesia was 5.1 +/- 1.8 %/mmHg, 4.4 +/- 1.0 %/mmHg respectively. CONCLUSION: The cerebral vasculature in healthy patients remains responsive to changes in PETCO2 during isoflurane-N2O and propofol-N2O anesthesia.
Anesthesia* ; Anesthetics ; Blood Flow Velocity* ; Carbon Dioxide* ; Carbon* ; Compliance ; Fentanyl ; Humans ; Hypocapnia ; Isoflurane ; Middle Cerebral Artery* ; Neurosurgery ; Propofol ; Succinylcholine ; Thiopental

This study was attempted to observe the rate of fall of arterial oxygen tension and the rate of rise of artetrial carbon dioxide tension after denitrogenation with 100%(Group I, n=10) or 50% oxygen(Group II, n=15) in 25 healthy ASA class I patients scheduled for ear, oromaxillary, head and orthopedic surgery that do not affect respiration or pulmonary function. After 30 minutes of denitrogenation under supine position, apnea was carried out by dis- connecting the endotracheal tube and rebreathing circuit until arterial oxygen saturation decreased to 90-95% by pulse oximetry which was placed at index finger. We calculated the mean rate of decrease of arterial oxygen tension (PaO2(tn)-PaO2(tn+1)) and the mean rate of increase of arterial carbon dioxide tension (PaCO2(tn+1)-PaCO2(tn)) minute by minute by arterial blood gas analysis. The results are as follows. 1) The mean rate of decrease of arterial oxygen tension after apnea was 40.96+/-11.02 in Group I and 43.22+/-5.49 mmHg/min. in Group II 2) The rate of increase of arterial carbon dioxide tension during the first one minute of apnea was 5.94+/-0.85 in Group I and 5.56+0.64 mmHg in Group II 3) The mean rate of increase of arterial carbon dioxide tension after first one minute was 2.46+/-0.78 in Group I and 2.47+/-0.71 mmHg/min. in Group II With the above results, we concluded that healthy human subject who was denitrogenated with 100% oxygen about 30 minutes can withstand apnea as far as 7 minutes, and those who denitrogenated with 50% oxygen can withstand apnea as far as 3 minutes without hypoxic insult.
Anesthesia* ; Anoxia ; Apnea* ; Blood Gas Analysis ; Carbon Dioxide* ; Carbon* ; Ear ; Fingers ; Head ; Humans ; Orthopedics ; Oximetry ; Oxygen* ; Respiration ; Supine Position