Experimental and modelling studies of carbon dioxide capture onto pristine,nitrogen-doped,and activated ordered mesoporous carbons

The search for suitable materials for carbon dioxide capture and storage has attracted the attention of the scientific community in view of the increased global CO₂ levels and its after-effects. Among the different materials under research, porous carbons and their doped analogues are extensively debated for their ability to store carbon dioxide at high pressures. The present paper examined high-pressure carbon dioxide storage studies of 1-D hexagonal and 3-D cubic ordered mesoporous pristine and N-doped carbons prepared using the nano-casting method. Excess carbon dioxide sorption isotherms were obtained using the volumetric technique and were fitted using the Toth model. Various parameters that influence CO₂ storage on metal-free ordered mesoporous carbons, such as the effect of pore size, pore dimension, pyrolysis temperature, the impact of nitrogen substitution, and the effect of ammonia activation are discussed. It was observed that the carbon dioxide storage capacity has an inverse relation to the total nitrogen doped, the amount of pyridinic nitrogen functionality, and the pyrolysis temperature, whereas the pore size seems to have a linear relationship. On the other hand, the presence of oxygen has a positive effect on the sorption capacity. Among the prepared ordered mesoporous carbons, the ammonia-treated one has shown the highest adsorption capacity of 37.8 mmol g⁻¹ at 34 bar and 0 °C.

The present paper discusses the shaping factors of metal-free ordered mesoporous carbon synthesis for carbon dioxide sorption at high pressures. These results can be used as future guidelines in preparing carbon for gas adsorption studies.     

Multiple complications and withdrawal syndrome associated with quetiapine/venlafaxine intoxication

OBJECTIVE: To report a case of quetiapine/venlafaxine intoxication associated with multiple complications and to review their possible relationship with these 2 drugs. CASE SUMMARY: A 53-year-old white man was admitted to the hospital for loss of consciousness secondary to voluntary intoxication with venlafaxine and quetiapine. Several complications were attributable to this intoxication including seizures, prolonged coma, respiratory depression, neuroleptic malignant syndrome, prolonged QRS and QTc intervals, and a possible venlafaxine withdrawal syndrome. DISCUSSION: Quetiapine could be responsible for the neuroleptic malignant syndrome presented in this case. Moreover, venlafaxine intoxication, fever, autonomic instability, and myoclonus presented serotonin syndrome as a differential diagnosis. Potential causes of seizures and prolongation of the QRS and QTc intervals are reviewed. Finally, prolonged coma and late venlafaxine withdrawal are discussed with regard to the pharmacodynamics and pharmacokinetics of drug elimination in the context of intoxication. CONCLUSIONS: Clinicians should be aware of possible complications following intoxication with atypical antipsychotics and anti-depressants, including protracted altered mental status.     

Li-doped beryllonitrene for enhanced carbon dioxide capture

In recent years, the scientific community has given more and more attention to the issue of climate change and global warming, which is largely attributed to the massive quantity of carbon dioxide emissions. Thus, the demand for a carbon dioxide capture material is massive and continuously increasing. In this study, we perform first-principle calculations based on density functional theory to investigate the carbon dioxide capture ability of pristine and doped beryllonitrene. Our results show that carbon dioxide had an adsorption energy of −0.046 eV on pristine beryllonitrene, so it appears that beryllonitrene has extremely weak carbon dioxide adsorption ability. Pristine beryllonitrene could be effectively doped with lithium atoms, and the resulting Li-doped beryllonitrene had much stronger interactions with carbon dioxide than pristine beryllonitrene. The adsorption energy for carbon dioxide on Li-doped beryllonitrene was −0.408 eV. The adsorption of carbon dioxide on Li-doped beryllonitrene greatly changed the charge density, projected density of states, and band structure of the material, demonstrating that it was strongly adsorbed. This suggests that Li-doping is a viable way to enhance the carbon dioxide capture ability of beryllonitrene and makes it a possible candidate for an effective CO₂ capture material.

Lithium-doped beryllonitrene monolayer can effectively chemisorb carbon dioxide molecules.     

Partial pressure of end-tidal carbon dioxide successful predicts cardiopulmonary resuscitation in the field: a prospective observational study

Introduction

Prognosis in patients suffering out-of-hospital cardiac arrest is poor. Higher survival rates have been observed only in patients with ventricular fibrillation who were fortunate enough to have basic and advanced life support initiated soon after cardiac arrest. An ability to predict cardiac arrest outcomes would be useful for resuscitation. Changes in expired end-tidal carbon dioxide levels during cardiopulmonary resuscitation (CPR) may be a useful, noninvasive predictor of successful resuscitation and survival from cardiac arrest, and could help in determining when to cease CPR efforts.

Methods

This is a prospective, observational study of 737 cases of out-of-hospital cardiac arrest. The patients were intubated and measurements of end-tidal carbon dioxide taken. Data according to the Utstein criteria, demographic information, medical data, and partial pressure of end-tidal carbon dioxide (Pet CO ₂) values were collected for each patient in cardiac arrest by the emergency physician. We hypothesized that an end-tidal carbon dioxide level of 1.9 kPa (14.3 mmHg) or more after 20 minutes of standard advanced cardiac life support would predict restoration of spontaneous circulation (ROSC).

Results

Pet CO ₂ after 20 minutes of advanced life support averaged 0.92 ± 0.29 kPa (6.9 ± 2.2 mmHg) in patients who did not have ROSC and 4.36 ± 1.11 kPa (32.8 ± 9.1 mmHg) in those who did (P < 0.001). End-tidal carbon dioxide values of 1.9 kPa (14.3 mmHg) or less discriminated between the 402 patients with ROSC and 335 patients without. When a 20-minute end-tidal carbon dioxide value of 1.9 kPa (14.3 mmHg) or less was used as a screening test to predict ROSC, the sensitivity, specificity, positive predictive value, and negative predictive value were all 100%.

Conclusions

End-tidal carbon dioxide levels of more than 1.9 kPa (14.3 mmHg) after 20 minutes may be used to predict ROSC with accuracy. End-tidal carbon dioxide levels should be monitored during CPR and considered a useful prognostic value for determining the outcome of resuscitative efforts and when to cease CPR in the field.     

Limitations of the triolein breath test.

Patients being investigated for intestinal absorptive capacity were classified as normals or malabsorbers on the basis of three fat absorption tests. Malabsorbers were further classified as mild, moderate, severe or gross according to severity of malabsorption. Using this classification system the triolein breath test was evaluated in 53 patients. Seventeen patients were excluded because their graph of percentage breath [14C]carbon dioxide versus time was exponential indicating that the peak [14C]-carbon dioxide may be occurring later than the six hour duration of the test. The sensitivity and specificity of the triolein breath test were found to be 100% and 96%, respectively and moderate correlations with the individual fat absorption tests were found. However, the breath test was limited in its capacity to predict the severity of malabsorption. Carbon dioxide output was also measured in order to determine the applicability of using an assumed value. The respiratory quotient and variability of results were high in nineteen patients indicating possible hyperventilation. In 32 patients with reproducible results and normal respiratory quotients the average carbon dioxide output was 8.66 mmol/kg per hour with a wide range of 5-12.4 mmol/kg per hour. Consequently the use of an assumed carbon dioxide output can introduce considerable errors in the triolein breath test. This study highlights drawbacks of the triolein breath test, particularly problems in using an assumed carbon dioxide output for its calculation, its inability to predict the severity of malabsorption and the nature of the dietary load used.     

End-tidal carbon dioxide measurements as a prognostic indicator of outcome in cardiac arrest.

PURPOSE: To evaluate the use of end-tidal carbon dioxide values in predicting survival in cardiopulmonary arrest. BACKGROUND: The decision about when to terminate resuscitative efforts for patients with cardiopulmonary arrest is often subjective. End-tidal carbon dioxide values have been suggested as potential objective criteriafor making this decision. METHODS: This study was a cooperative effort of the St Louis chapter of the American Association of Critical-Care Nurses and its members and involved 6 hospitals and an air evacuation service. All adult patients who had a cardiopulmonary arrest were eligiblefor the study. Once a patient with cardiac arrest was intubated, end-tidal carbon dioxide and cardiac rhythms were measured and recorded every 5 minutes for 20 minutes or until resuscitation efforts were terminated. Patients' survival at the time of the arrest, survival 24 hours after the arrest, and discharge status were followed up. RESULTS: A total of 127 patients were enrolled in the study. All but 1 patient with end-tidal carbon dioxide values less than 10 mm Hg died before discharge. End-tidal carbon dioxide values greater than 10 mm Hg were associated with various degrees of survival. Overall survival to discharge was less than 14%, regardless of the end-tidal carbon dioxide value. CONCLUSION: Measurements of end-tidal carbon dioxide can be used to accurately predict nonsurvival of patients with cardiopulmonary arrest. End-tidal carbon dioxide levels should be monitored during cardiopulmonary arrest and should be considered a useful prognostic value for determining the outcome of resuscitative efforts.     

Effects of interventional lung assist on haemodynamics and gas exchange in cardiopulmonary resuscitation: a prospective experimental study on animals with acute respiratory distress syndrome

Introduction  

Interventional lung assist (ILA), based on the use of a pumpless extracorporeal membrane oxygenator, facilitates carbon dioxide (CO₂) elimination in acute respiratory distress syndrome (ARDS). It is unclear whether an ILA system should be clamped during cardiopulmonary resuscitation (CPR) in patients with ARDS or not. The aim of our study was to test the effects of an ILA on haemodynamics and gas exchange during CPR on animals with ARDS and to establish whether the ILA should be kept open or clamped under these circumstances.     

Carbon monoxide poisoning: A Review epidemiology,pathophysiology, clinical findings,and treatment options including hyperbaric oxygen therapy

Abstract

Carbon monoxide (CO) poisoning is the leading cause of poisoning deaths (accidental and intentional) in the United States. While confirmation of CO poisoning is easily obtained via assessment of carboxyhemoglobin (COHgb) levels, evaluation of the severity of intoxication is both difficult and inconsistent. Acute intoxication most commonly results in neurologic dysfunction and/or myocardial injury. Delayed neurologic sequelae are observed in approximately 10% of patients. New information from clinical observations and animal research has prompted a re-evaluation of the clinical assessment of the severity of CO intoxication and its resultant pathophysiology. Patients at the extremes of age (the very young and the elderly), those with pre-existing cardiovascular and/or pulmonary disease, as well as pregnancy are at increased risk. Once the diagnosis of CO poisoning has been established, treatment with 100% 0₂ is indicated. Based on the body of clinical, basic and scientific information currently available, patients who manifest signs of serious intoxication (i.e., unconsciousness or altered neurologic function, cardiac or hemodynamic instability) should be considered candidates for hyperbaric oxygen therapy (HBO) in addition to other appropriate supportive and intensive care. Any patient who has suffered an interval of unconsciousness, regardless of the patient's clinical exam on arrival, warrants HBO therapy. Treatment plans based on any specific COHgb level are not well founded.     

STUDIES ON THE BLOOD VESSELS IN THE MEMBRANES OF CHICK EMBRYOS : PART IV. MODIFICATION OF IRRITABILITY OF THE BLOOD VESSELS

When faradic stimulation was undertaken of vessels irrigated with Ringer''s solution, which alternately contained and was free from carbon dioxide, it was observed that the reaction was far less when the solution contained carbon dioxide. A reversal of the effect could be obtained many times. It appears, therefore, that when Ringer''s solution contained carbon dioxide in the concentration described, the irritability of the vessels to electrical stimuli decreased, although carbon dioxide by itself and in the absence of the application of the stimuli, appeared to be void of effect upon the vessels. The rare, divergent results were traced to technical errors. We attempted to discover whether the observed decrease in irritability of the vessels might not be due to the absence of oxygen. For this purpose we irrigated the vessels with Ringer''s solution alternately containing nitrogen and oxygen. When nitrogen caused any change this was due to an influence on the rate of the heart and not on the irritability or reactivity of the arteries. In whatever way we tried we were unable to bring about a change in reactivity of the arteries by creating a condition of oxygen lack independently of a change in the rate of the heart beat. We attempted to study also the effect of other acids beside carbon dioxide on the changed reactivity of the arteries. Irrigation with various concentrations of lactic acid was without result. We also employed solutions buffered with potassium and sodium phosphate. When the irrigation was undertaken with these solutions having a pH range varying from 7.7 to 5.9 we observed neither a direct action nor one which modified the preparation in such a way as to change its susceptibility to faradic stimulation. Important investigations have been published recently by Atzler and Lehmann (2) on the direct influence of the hydrogen ion concentration on the behavior of blood vessels. Hammett and Zoll believed that, as the result of their experiments in which they attempted to bring about stimulation with solutions of concentrated carbon dioxide, they were able to exclude the possibility of action due to acid alone and therefore ascribed to carbon dioxide a specific effect. In our own experiments the method of irrigation does not permit an inference whether, or how far, an acid effect plays a rôle in the carbon dioxide experiments. For beside the question of hydrogen ion concentration and of buffering, the question of the penetration of substances from the surface to the contractile elements of the wall of the vessels requires to be considered. Carbon dioxide has an ability, beyond that of all other substances, to penetrate through tissues (3). It may be owing to this property that we could influence the reactivity of the blood vessels with it and it alone. This possibility must be further investigated. In these experiments, however, it was our object to show only that it was possible to influence the irritability of blood vessels experimentally. The conclusion is justified by our experiments that carbon dioxide in small concentrations reduces the threshold of irritability for electrical stimuli of the blood vessels of the embryonic membrane.     

Hypercapnic Coma Due to Spontaneous Pneumothorax: Case Report and Review of the Literature

Background: Hypercapnic coma is a rare differential diagnosis in the unconscious patient. One underlying mechanism may be hypoventilation due to spontaneous pneumothorax. Although hypercapnia is not a typical finding in spontaneous pneumothorax in patients with otherwise healthy lungs, under certain circumstances, hypercapnia may readily develop. Objectives: We report a rare case of profound hypercapnic coma due to spontaneous pneumothorax after contralateral pneumonectomy. In addition, we review other causes of hypercapnic coma and its outcome and discuss the relationship between arterial carbon dioxide partial pressure and level of consciousness. Case Report: An 85-year-old man without evidence of trauma or intoxication presented unconscious to our Emergency Department. The physical examination and X-ray study revealed a left-sided spontaneous pneumothorax. A right-sided pneumonectomy 25 years earlier had promoted the development of profound hypercapnic coma. After insertion of a thoracic drain, the coma rapidly resolved without any neurological deficit. Conclusions: Although severe hypercapnia is usually due to decompensation of chronic lung disease, pneumothorax potentially may cause hypercapnic coma. Review of the literature suggests that there is no close correlation between arterial pCO₂ (partial pressure of CO₂) levels and the degree of impairment of consciousness; however, levels exceeding 80 mm Hg are likely associated with significantly impaired consciousness. Hypercapnic coma usually resolves without neurological deficit as arterial pCO₂ tensions decline.     

Carbon dioxide kinetics and capnography during critical care

Greater understanding of the pathophysiology of carbon dioxide kinetics during steady and nonsteady state should improve, we believe, clinical care during intensive care treatment. Capnography and the measurement of end-tidal partial pressure of carbon dioxide (PETCO₂) will gradually be augmented by relatively new measurement methodology, including the volume of carbon dioxide exhaled per breath (VCO_2,br) and average alveolar expired PCO₂ (PǢCO₂). Future directions include the study of oxygen kinetics.     

An Educational Intervention to Improve Comfort with Applying and Interpreting Transcutaneous CO2 and End-tidal CO2 Monitoring in the PACU

PurposeThe purpose of this study was to assess the effectiveness of an educational program about measuring ventilation using devices that assess carbon dioxide levels in patients recovering from a surgical procedure.DesignA pre-post survey of knowledge attainment from an educational intervention about measuring ventilation using end-tidal carbon dioxide (EtCO₂) and transcutaneous carbon dioxide (tcPCO₂) devices in the postanesthesia care unit (PACU) was distributed to current members of the American Society of PeriAnesthesia Nurses.MethodsParticipants received a 12-question pre-intervention (five were related to demographics) and a five-question post-intervention survey. Non-demographic survey questions used a one to five Likert scale to assess comfortability or confidence. The intervention created was a voice-over presentation designed to improve PACU RN's comfort and confidence with using and interpreting tcPCO₂ or EtCO₂ in the PACU.FindingsPACU RNs (N = 108) reported they ‘never’ or ‘rarely’ used EtCO₂ (n = 57, 52.7%) monitoring or tcPCO₂ (n = 93, 86.1%) monitoring in the PACU. A paired t test revealed statistically significant differences in the PACU RN's pre-survey and posttest comfortability of applying and interpreting EtCO₂ or tcPCO₂ monitors (P < .05).ConclusionsCapnography monitoring should be considered a standard of care for PACU patients. Education of registered nurses working in the PACU is critical before implementing EtCO₂ or tcPCO₂ monitoring.     

Anionic CO2 activation in the anionic and di-anionic state of aza-naphthalene

Nitrogen-containing polycyclic aromatic hydrocarbon (PAH) is the single basic moiety in N-doped graphene, the only metal-free catalyst reported to date to successfully produce the oxygen reduction reaction. N-doped graphene is quite promising as a material to increase the efficiency of oxygen reduction. In addition, it is known that when carbon dioxide is added to aza-benzene, there will be an associative chemical reaction upon electron attachment between the anionic nitrogen atoms in the aza-benzene and the carbon atom in the carbon dioxide; however, it has previously been reported that when there are more nitrogen atoms in the small aza-benzene moiety, the associative reaction does not always occur. In this study, we carried out a theoretical simulation to determine whether more electrons increase the CO₂ reductive reactivity of the aza-naphthalene as a model system of a nitrogen-containing polycyclic aromatic hydrocarbon. We found that even though an associative chemical reaction between nitrogen atoms in the N-PAH and carbon atoms in carbon dioxide did not occur in anionic complexes of aza-naphthalene and carbon dioxide, chemical reactions did occur in all the nitrogen atoms of these complexes when we added an extra excess electron. Therefore, we conclude that the efficiency of CO₂ reduction will be increased in nitrogen atoms when more electrons are added to increase their anionic properties.

Nitrogen-containing polycyclic aromatic hydrocarbon (PAH) is the single basic moiety in N-doped graphene, the only metal-free catalyst reported to date to successfully produce the oxygen reduction reaction.     

百草枯中毒的早期急救及预后因素分析

目的分析影响急性百草枯中毒患者预后的因素以及治疗方法,以提高患者生存率,为临床急救提供依据。方法对本院急诊2012年4-12月收治的36例急性百草枯中毒患者的资料进行回顾性分析,按是否生存将患者分为存活组和死亡组,对2组患者服毒量、服毒至洗胃时间、首次血液净化时间、白细胞计数（WBC）、丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）、总胆红素（TBIL）、结合胆红素（DBIL）、动脉血二氧化碳分压（PCO2）进行比较。结果存活组与死亡组在服毒量、WBC、ALT、AST、TBIL、DBIL、PCO2方面差异均有统计学意义（P〈0．05）。结论百草枯中毒病情危重,死亡率极高,早期进行全面抢救治疗可延长患者生命,同时密切关注上述血生化指标,能较好地评估患者病情严重程度以及预后。     

Sensitivity of a disposable end-tidal carbon dioxide detector

A small disposable carbon dioxide detector that can be used to provide evidence of correct endotracheal tube placement is now commercially available (FEF). The device contains an indicator that changes color when exposed to carbon dioxide. This study measured the lowest concentration of carbon dioxide causing a perceivable color change in the device. Ten volunteers were blinded to the concentrations of carbon dioxide in an airway circuit/lung model, and the minimal concentration of carbon dioxide that caused a perceivable color change was recorded. The mean minimum concentration required for detection of a color change was 0.54% (4.1 mm Hg) and ranged from 0.25 to 0.60% (1.9 to 4.6 mm Hg). We conclude that this device should produce a detectable color change even in patients with low end-tidal carbon dioxide, as might be observed during cardiopulmonary resuscitation.Presented in part at the annual meeting of the American Society of Anesthesiologists, New Orleans, October 1989.     

THE EFFICIENCY OF VARIOUS DIURETICS IN THE ACUTELY NEPHROPATHIC KIDNEY,PROTECTED AND UNPROTECTED BY SODIUM CARBONATE. II

The outline which has been given of the relative toxicity of Gréhant''s anesthetic in normal animals, in animals that were nephropathic from uranium and protected against the anesthetic by an alkaline solution, and in those animals which were unprotected by such a solution, furnishes the basis for the following summary. The kidney of the normal dog is relatively non-susceptible to the toxic action of Gréhant''s anesthetic. The kidneys have failed to show any change in their histological structure during the period of anesthesia. These animals have remained diuretic during the period of anesthesia and have responded to diuretics such as theobromine, pituitrin, and solutions of urea and sodium chloride. Normal animals anesthetized with Gréhant''s mixture for 1½ hours usually show at the end of the experiment either no change, or only a slight variation from the normal, in the hydrogen ion content of the blood, the alkali reserve of the blood, and in the tension of carbon dioxide. In several normal dogs which were over 4 years of age, by the end of an anesthesia of such a duration the animals have shown a reduction in the alkali reserve of the blood and also a decrease from the normal in the carbon dioxide tension of alveolar air. From this observation it would appear that even in a normal animal Gréhant''s anesthetic tends to induce an acid intoxication, and as was the case with normal animals which were being intoxicated by uranium, such an intoxication is more readily induced in an old animal than in a young one. The nephropathic animals which have been anesthetized by Gréhant''s anesthetic and in which an attempt has been made to protect these animals against the toxic effect of the anesthetic by the use of asolution of sodium carbonate fall into two clear-cut groups. Those animals of the series not over 1½ years old have shown at the end of the uranium intoxication and prior to the use of the anesthetic a less severe acid intoxication than have the animals of the series which were over 1½ years old. In this younger group of animals the intravenous injection of a 3 per cent solution of sodium carbonate immediately before the animals were anesthetized has succeeded in protecting these animals against the toxic action of the anesthetic. During the following 1½ hours of anesthetization these animals have not developed a severe grade of acid intoxication, and in several of the animals at the end of the experiment the alkali reserve of the blood was in excess of what it was at the end of the uranium intoxication and before an anesthetic was administered. Animals of this protected group have remained diuretic throughout the experiment and have shown an active diuresis from pituitrin, theobromine, and solutions of urea and sodium chloride. The kidneys of such animals have shown histologically a normal vascular tissue, a convoluted tubule epithelium which gave the appearance of being hyperactive, and only occasionally were tubules encountered which showed signs of an early epithelial degeneration. The nephropathic animals of the series in which a solution of sodium carbonate failed to afford any protection against Gréhant''s anesthetic were animals over 1½ years old in which the uranium intoxication had resulted in a severer grade of add intoxication than in the younger animals. When these older animals were given intravenously the carbonate solution and were anesthetized, it was found impossible to increase the alkali reserve of the blood to the same extent as was possible in the younger animals. Furthermore, the alkaline solution during the period of anesthesia is rapidly used up so that by the termination of these experiments the animals may have an alkali reserve of the blood which may be even lower than was the alkali reserve before the use of the carbonate. These animals have remained completely anuric throughout the experiments and have shown no diuretic effect from those diuretics which in the animals that were successfully protected by the carbonate induced free diuresis. The kidneys of these anuric animals show no degenerative changes in the glomerular vessels. The capillaries are not distended with blood as has been the case with the diuretic group. The epithelium of the convoluted tubules is acutely swollen. The swelling has frequently taken place to such an extent that the lumen of the tubules has become obliterated. The nephropathic animals of the series which served as control animals and which were given a solution of sodium chloride equimolecular with the carbonate solution, following Gréhant''s anesthetic became completely anuric. The sodium chloride solution furnished no protection against the anesthetic. The animals of all ages became anuric and unresponsive to the diuretic substances which have been used during this study. With the establishment of a state of anuria in these control animals the hydrogen ion content of the blood has increased, the alkali reserve of the blood has been rapidly depleted, and associated with this change the carbon dioxide tension has been reduced. The rapidity with which these changes develop and the degree of acid intoxication which is induced is more marked in these animals than in any of the other series. The kidneys of the control animals show the severest grade of degeneration of any of the nephropathic animals. The epithelium of the convoluted tubules is not only severely swollen but the cells frequently show necrosis. The loops of Henle contain more stainable fat than has been demonstrated in the kidneys of the carbonate animals.     

Development of hypoglycemia is associated with death during carbon monoxide poisoning

A significant fraction of carbon monoxide (CO) poisoning victims die before discovery or rescue. Although survivors usually show normal or elevated blood glucose, data from an animal model now suggest an association between low blood glucose and death during CO poisoning. Hypoglycemia observed during the later stages of CO poisoning in the rat was intensified by increased CO concentration (2,400 ppm, 2,700 ppm, 3,000 ppm) and by the infusion or injection of normal saline, both in survivors and in nonsurvivors, but glucose lowering was especially marked in the latter group. Mortality rate was similarly increased by these two conditions. Based on the change in blood glucose concentration early in CO poisoning, it should be possible to identify survivors and nonsurvivors. Survivors showed a hyperglycemic “rebound” 2 hours after CO. Nonsurvivors tended to maintain a higher body temperature and heart rate, and a relatively smaller decrease in blood pressure during CO exposure, presumably due to a higher metabolic rate. This is possibly a major factor responsible for the rapid lowering of blood glucose concentration. Concurrent administration of ethanol to two to four times the legal intoxication blood level in humans did not alter the severity of CO-induced hypoglycemia in either survivors or nonsurvivors, but did increase survival and exacerbated “rebound” hyperglycemia in survivors. Blood ethanol concentration is elevated by CO poisoning in a dose-dependent manner. The likely mechanisms) underlying CO-induced hypoglycemia, the complicating effect of concurrent ETOH intoxication, and their clinical relevance are discussed.     

Volumetric and reflective device dead space of anaesthetic reflectors under different conditions

Inhalation sedation is increasingly performed in intensive care units. For this purpose, two anaesthetic reflectors, AnaConDa? and Mirus? are commercially available. However, their internal volume (100 ml) and possible carbon dioxide reflection raised concerns. Therefore, we compared carbon dioxide elimination of both with a heat moisture exchanger (HME, 35 ml) in a test lung model. A constant flow of carbon dioxide was insufflated into the test lung, ventilated with 500 ml, 10 breaths per minute. HME, Mirus and AnaConDa were connected successively. Inspired (insp-CO₂) and end-tidal carbon dioxide concentrations (et-CO₂) were measured under four conditions: ambient temperature pressure (ATP), body temperature pressure saturated (BTPS), BTPS with 0.4 Vol% (ISO-0.4), and 1.2 Vol% isoflurane (ISO-1.2). Tidal volume increase to maintain normocapnia was also determined. Insp-CO₂ was higher with AnaConDa compared to Mirus and higher under ATP compared to BTPS. Isoflurane further decreased insp-CO₂ and abolished the difference between AnaConDa and Mirus. Et-CO₂ showed similar effects. In addition to volumetric dead space, reflective dead space was determined as 198?±?6/58?±?6/35?±?0/25?±?0 ml under ATP/BTPS/ISO-0.4/ISO-1.2 conditions for AnaConDa, and 92?±?6/25?±?0/25?±?0/25?±?0 ml under the same conditions for Mirus, respectively. Under BTPS conditions and with the use of moderate inhaled agent concentrations, reflective dead space is small and similar between the two devices.     

A Stochastic Control Program to Predict Outcome and to Support Therapeutic Decisions: A Preliminery Report

Background and Objectives. Early noninvasive hemodynamic monitoring with an outcome predictor and a therapeutic decision support system may be useful to identify and correct hemodynamic deficiencies in emergency patients. The first aim was to apply a stochastic (probability) search and display model to predict outcome as early as possible. The second aim was to explore the usefulness of a therapeutic decision support system to evaluate the relative effectiveness of various therapies. Methods. A stochastic control and display program based on noninvasive hemodynamic monitoring was applied in 100 consecutive critically ill patients admitted to the emergency department of an inner city public hospital. The program continuously displayed the noninvasive hemodynamic data and the patient's predicted survival probability (SP) that was based on the patient's diagnosis, covariates, and hemodynamic data. The accuracy of the SP at the initial resuscitation on admission to the emergency department (ED) was evaluated by the actual outcome at hospital discharge. The therapeutic decision support program evaluated the relative effectiveness of various therapies on based on their hemodynamic and SP responses and outcome of patients with similar clinical-hemodynamic states. Results. The cardiac index, mean arterial pressure, arterial saturation, transcutaneous oxygen and carbon dioxide tensions were appreciably higher in survivors than in nonsurvivors in the initial resuscitation. Heart rate was higher in the nonsurvivors. The calculated Survival Probability (SP) of survivors averaged 81 ± 1.4% in the first 24-hour observation period. It was 58 ± 2.2% for nonsurvivors during this period. Misclassifications were 10/100 or 10%. The content of the information does not necessarily reflect the position or policy of the Government, and no official endorsement should be inferred.