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

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

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

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

One hundred patients with hyperventilation syndrome presenting to emergency department(ED) were studied. Those were diagnosed on clinical basis by emergency medical physician. The male to female ratio was 15 : 85. In monthly distribution, the numbers of patients were increased during the two months, June and July. The 41% of patients visited the emergency center from 9:00 p.m. to 3:00 a.m.. The most common predisposing factors were the domestic problems, especially those between husband and wife(37%). Presenting complaints were dyspnea(34), paresthesia(30), muscle spasm(24), dizziness(6) and palpitation(6 patients). The initial examination of the patients in the ED were as follows, systolic blood pressure(134+/-7.15mmHg), heart rate(87.67+/-14.34/minute), respiratory rate(22.21+/-3.34/minute) and body temperature(36.61+/-0.31 degrees C, n=98). Arterial blood gas analysis showed alkalemia(pH 7.51+/-0.09) and hypocapnia(PCO2 26.67+/-8.30mmHg). After emergency cares, including carbone dioxide re-breathing and antianxietics, most of the symptoms were disappeared. The mean duration of stay in ED was 3.27+/-0.23 hours. The most important considerations in diagnosis of hyperventilation syndrome was the patients's history and the effective management was carbon dioxide rebreathing for a few minutes and antianxietics.
Blood Gas Analysis ; Carbon ; Carbon Dioxide ; Causality ; Diagnosis ; Emergencies* ; Emergency Service, Hospital* ; Female ; Heart ; Humans ; Hyperventilation* ; Male ; Spouses

BACKGROUND: Propofol is a relatively new intravenous anesthetic agent, and the cerebral blood flow (CBF) response to changes in PaCO2 during propofol anesthesia has not been extensively studied. The purpose of this study was to investigate the effects of propofol anesthesia on the CBF response to changes in PaCO2 in dogs. METHODS: In six dogs, after surgical preparation for posterior sagittal sinus outflow method, loading dose of propofol 5~6 mg/kg was injected and then anesthesia was maintained with a propofol infusion of 20 mg . kg-1 . hr-1 during study. Ventilation was controlled to hypocapnia(PaCO2 20~35 mmHg), normocapnia(PaCO2 35~45 mmHg) and hypercapnia(PaCO2 45~60 mmHg) by adjustment of minute ventilation. Posterior sagittal sinus blood flow was measured by metered syringe and then CBF was calculated. Cerebral metabolic rate for oxygen(CMRO2) was calculated with arterial and sagittal sinus blood analysis. RESULTS: CBF at normocapnia (PaCO2 41+/-5 mmHg) was 28.7+/-11.6 ml . 100 g-1 . min-1 which increased to 46.5+/-14.4 ml . 100 g-1 . min-1 and decreased to 22.1+/-8.9 ml . 100 g-1 . min-1 on increasing PaCO2 (63+/-18 mmHg) and decreasing PaCO2 (33+/-3 mmHg), respectively. The slope of CBF versus PaCO2 was 1.29 ml . 100 g-1 . min-1 . mmHg. Blood pressure, herat rate, PaO2, CMRO2 were not changed between groups. CONCLUSIONS: CBF response to changes in PaCO2 during propofol anesthesia is maintained and the slope of the CBF-CO2 response is similar to that found during anesthesia with other intravenous agents such as thiopental, midazolam, etomidate, opioids.
Analgesics, Opioid ; Anesthesia* ; Anesthetics ; Animals ; Blood Pressure ; Carbon Dioxide* ; Carbon* ; Dogs* ; Etomidate ; Midazolam ; Propofol* ; Syringes ; Thiopental ; Ventilation

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