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PubMed1976

[Alteration of textilfibres by explosion gases expelled distant from the muzzle (author's transl)].

This paper presents the reconstruction of an unusual case of suicide. After raiding a branch-bank a robber fled shooting with his Sauer-Western revolver caliber .44 magnum at the pursuing policemen and succeeded in wrestling a pistol Walther caliber 7,65 mm from them. Under the fire of sub-machine guns he destroyed himself by a shot to the neck. Our investigations concerned a textile damage at the front of the sweater of the deceased surrounded by primer residue, showing characteristics of a close-up shot. The damage was identified as effect of explosion gases exhausting far-off the muzzle. The distance between this injury and the bullet hole corresponded with the length of the barrel of the Sauer-Western revolver and could be used for identification; it confirmed the diagnosis of a close-up shot at the neck, too. Collateral experiments with shots from distant ranges developed spadiceous melt figures of textile fibers around the bullet hole, the appearance of which is considered proof for a close-up shot commonly.

Autopsy↗
PubMed1990

Effect of endotracheal suctioning on arterial blood gases in children.

The occurrence of hypoxia during endotracheal tube suctioning and its prevention was examined in 25 hemodynamically stable and non-cyanosed pediatric patients. In each patient 4 suction and treatment protocols were studied: 1. pre- and post-suction arterial blood gases (ABG) with no treatment (control). 2. ABG with pre-suction oxygenation. 3. ABG with presuction hyperinflation. 4. ABG with postsuction hyperinflation. With no presuction treatment the PO2 and saturation fell significantly after suctioning from control level of 116.6 +/- 9.4 mmHg to 93 +/- 9.3 mmHg post-suction and 97.2 +/- 0.4% to 92.8 +/- 1.4% (p less than 0.001) respectively. In 6 patients with low but adequate pre-suction PO2, hypoxic levels (PO2 less than 60 mmHg) were found post-suction. The significant fall in PO2 was completely prevented by pre-suction oxygenation. Post-suction hyperinflation induced a rapid return of the PO2 to control levels. These results suggest that severe hypoxia might occur during endotracheal suctioning and can be prevented by pre-oxygenation. We recommend 1 min oxygenation with FiO2 1.0 prior to suctioning procedures and intermittent hyperinflation with 100% oxygen during repeated endotracheal suction passes to prevent hypoxia, especially in children in respiratory failure who already have low or borderline pre-suction PO2.

Blood Gas Analysis↗
PubMed1977

Prevention of obstruction of nasopharyngeal CPAP tubes by adequate humidification of inspired gases.

Nasopharyngeal CPAP is a simple and useful technique for increasing FRC and stimulating respiration in small premature infants. However, as it is essentially a non-rebreathing technique, the gases used should be warmed and saturated to the level normally found in the pharynx with no artificial airway present (31 degrees to 33 degrees C, 90 per cent plus relative humidity). If this is not done, crusting, mucous plugging, atelectasis, hypoxia, and infection will occur rapidly. Excess humidity should also be avoided.

Humans↗
PubMed1992

[The measurement of pH and gases in the blood using microanalysis: the effect of storage at 4 degrees C for an hour. A study in the rat].

The effects of one hour storage at 4 degrees C on micro blood gas samples (150 microliters) were studied for a wide range of values (pH: 7.11-7.58; PCO2: 26-97 mmHg; PO2: 31-503 mmHg) in 20 rats with indwelling carotid artery catheters. Blood gas values were modified by varying the composition of inspired gases: normoxia, hypocapnic hypoxia, hyperoxia, hypercapnia (in this case eight animals were anaesthetized with halothane 1.1%). One hundred and eight double micro-samples were taken. For each double sample, one was analysed immediately (H0) and compared with the second sample after one hr storage at 4 degrees C (H1). The Bland and Altman method was used for the statistical analysis of results. After one hr storage at 4 degrees C, the PCO2 was slightly higher than at H0 (mean difference +/- SD: +1.08 +/- 1.7 mmHg) and arterial pH was slightly lower (mean difference +/- SD: -0.016 upH +/- 0.011 upH). These results show that for these two variables, in the range studied, one hour storage at 4 degrees C had little effect. In contrast, for arterial PO2 the mean difference between all measurements between H1 and H0 was -17 +/- 25 mmHg. If results lower than 200 mmHg (56 double samples) are considered separately, the mean difference between values at H1 and H0 was only -0.98 +/- 5.3 mmHg. For PaO2 greater than 200 mmHg (52 double samples), the mean difference was -34 +/- 26.3 mmHg; this may be due to low reproducibility of measurements of elevated PO2 levels and to the effects of cellular metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed1997

[The i-STAT analyzer. A new, hand-held device for the bedside determination of hematocrit, blood gases, and electrolytes].

UNLABELLED: Exact and quick measurements of basic laboratory parameters are important in selected patients in the perioperative period. Depending on the capabilities of a hospital's central laboratory, the anaesthesiologist may only obtain such laboratory tests after unacceptable delays. This problem may be overcome by a new bedside measurement device that has become available from i-STAT Corporation, Princeton, USA. The hand-held, battery-driven analyser accepts blood specimens that are injected into a disposable cartridge (EG7+) and measures acidity, blood gas tensions, haematocrit, and electrolytes. The aim of this study was to determine the accuracy of such measurements by comparing them with measurements obtained by conventional laboratory test methods. METHODS: Heparinised arterial blood specimens were collected in duplicate from 49 surgical patients. Measurements of ionised calcium (Ca), sodium (Na), potassium (K), pH, pCO2, pO2, base excess (BE), haematocrit (Hct), and haemoglobin (Hb) obtained by the i-STAT analyser were compared with measurements from the calibrated analysers ABL 615 and EML 100 (Radiometer, Copenhagen). Because the i-STAT analyser calculates the Hb concentration from a conductometrically measured Hct, 19 blood specimens were centrifuged in order to compare test results with conventionally obtained Hct and Hb values. As the Hct test sensitivity with the i-STAT changes with diluted blood due to its low albumin concentration, Hct and Hb measurements during cardio-pulmonary bypass (CPB) must be corrected by activating an analyser-implemented correction algorithm (Hct/CPB and Hb/CPB). Correlation analysis was performed between conventional measurements and i-STAT values (Ca, Na, K, Hct, pCO2, pO2), between values that the i-STAT analyser derives (Hb, HCO3, BE) and conventionally obtained results, and between normal and CPB-corrected Hct and Hb values. Accuracy was judged according to the national quality standard, which requires test results to lie within the 95% confidence interval of conventional tests. RESULTS: Each blood specimen was analysed: erroneous results or technical failures did not occur. Measurement of one set of i-STAT values required 2.5 min. Correlation coefficients (r) between conventional and i-STAT results were: 0.85 for CA, 1.0 for K; 0.86 for Na; 0.99 for pH; 0.98 for pCO2; 0.99 for pO2; 0.93 for HCO3; 0.93 for BE; 0.46 for Hb values not corrected for CPB and 0.95 for CPB-corrected Hb; and 0.74 for Hct values not corrected for CPB and 0.98 for CPB-corrected Hct. The correlation coefficient for Hct between centrifuged and CPB-uncorrected i-STAT values was 0.81 and that for CPB-corrected values was 0.98. National accuracy requirements were not met for tests of: Ca (by 0.02 mmol/l); pH (by 0.01); pO2 including hyperoxic values (by 26.7 mmHg, but were met for pO2 values < 200 mmHg); Hb (by 1.6 g/dl); Hb/CPB (by 0.8 g/dl); and Hct (by 6.5%, but were met for Hct/CPB values). All other tests fulfilled the required standards. CONCLUSION: This analyser is easy to use, reliable, and portable, and therefore suitable for the operating room, for analyses during emergencies, on peripheral wards, for preclinical screening, or at times when availability of lab tests is time-consuming or limited. The test accuracy for electrolytes, blood gases, and Hb is high enough to justify routine use of the i-STAT analyser in clinical practice. That the nationally required quality standards for Ca, pH, and Hb were not met is not of importance because the measured deviation was too small to have clinical relevance. When analysing diluted blood with a low Hct and low oncotic pressure, it is important to activate the analyser's correction algorithm "CPB", because the obtained results will then comply with the required accuracy.

Blood Gas Analysis↗
PubMed2002

Bose-Einstein condensation in dilute atomic gases.

Bose-Einstein condensation is one of the most curious and fascinating phenomena in physics. It lies at the heart of such intriguing processes as superfluidity and superconductivity. However, in most cases, only a small part of the sample is Bose-condensed and strong interactions are present. A weakly interacting, pure Bose-Einstein condensate (BEC) has therefore been called the "holy grail of atomic physics". In 1995 this grail was found by producing almost pure BECs in dilute atomic gases. We review the experimental development that led to the realization of BEC in these systems and explain how BECs are now routinely produced in about 25 laboratories worldwide. The tremendous experimental progress of the past few years is outlined and a number of recent experiments show the current status of the field. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00114-001-0277-8.

Journal Article↗
PubMed2006

Laser-induced ablation of a steel sample in different ambient gases by use of collinear multiple laser pulses.

The sensitivity of laser-induced breakdown spectroscopy of solid samples depends on the number of ablated and excited analytes. Laser ablation of solid samples can be enhanced by using collinear multiple laser pulses, for example double or triple pulses, rather than single laser pulses with the same total laser pulse energy. The ablation rates and the plasma conditions are affected by the ambient gas. In this study laser ablation was examined by varying the interpulse separation of the multiple pulses, within double and triple-pulse bursts, and the gas mass density at constant gas pressure. Different ambient gases and gas mixtures consisting of argon, oxygen, and nitrogen were used to study their effect on ablation rates. In a pure argon atmosphere (99.999% v/v Ar) the ablation burst number required to penetrate a steel plate of thickness 100 microm is reduced by a factor of approximately six by use of triple-pulse bursts with a symmetric interpulse separation of 15 micros rather than single pulses with the same total burst energy of 105 mJ. For double and single pulses the factors are 1.6 for Ar and 2.8 for synthetic air. Analyte lines are 4 to 8 times more intense if an argon atmosphere, rather than air, is used.

Journal Article↗
PubMed2000

Ultra trace detection of perfluorocarbon tracers in reservoir gases by adsorption/thermal desorption in combination with NICI-GC/MS.

A new method for the analysis of perfluorocarbon tracers (PFTs) in reservoir samples based on adsorption/thermal desorption in combination with NICI-GC/MS is presented. The tracer compounds were trapped in tubes filled with a carbon molecular sieve and in a two-step procedure thermally desorbed before they were analyzed with NICI-GC/MS. The chromatographic background noise, visible on GC/ECD-systems, due to compounds normally present in petroleum reservoir gases, could not be seen with NICI-GC/MS. Determination of the perfluorocarbons in reservoir gas samples confirmed the applicability of the method. Tracer concentrations as low as 42 femtoliter/liter were detected.

Journal Article↗
PubMed1996

The use of different plasma gases (Ar, N(2) and air) for CMP-OES: figures of merit and temperature measurements.

A comparative study of a 600 W capacitively coupled microwave plasma (CMP) operated with different plasma gases (Ar, N(2) and air) with respect to the achieved detection limits for Fe, Cr, Zn, Ca and Mg have been carried out. Radially and axially resolved rotational temperatures (T(rot)), excitation temperatures (T(exc)) and electron number densities (n(e)) of these plasmas have been determined using OH (T(rot)), Fe (T(exc)) and Mg (n(e)) as thermometric species. The influence of different gas flow rates on T(rot), T(exc) and n(e), and of Li as an easily ionized element on T(exc) has been investigated.

Journal Article↗
PubMed1997

Bacterial degradation of styrene in waste gases using a peat filter.

A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12 g m-3 h-1 (max. 30 g m-3 h-1). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH to a neutral level and efficient control of the humidity. Maintenance of the water balance was easier in a down-flow than in an up-flow process, the former consequently resulting in much better filtration efficiency. The optimum operation temperature was around 23 degrees C, but the styrene removal was still satisfactory at 12 degrees C. Seven different bacterial isolates belonging to the genera Tsukamurella, Pseudomonas, Sphingomonas, Xanthomonas and an unidentified genus in the gamma group of the Proteobacteria isolated from the microflora of active peat filter material were capable of styrene degradation. The isolates differed in their capacity to decompose styrene to carbon dioxide and assimilate it to biomass. No toxic intermediate degradation products of styrene were detected in the filter outlet gas or in growing cultures of isolated bacteria. The use of these isolates in industrial biofilters is beneficial at low styrene concentrations and is safe from both the environmental and public health points of view.

Biodegradation, Environmental↗
PubMed1998

[Duplex ultrasound examinations of retinal circulation after inhalation of various mixed respiratory gases].

BACKGROUND: Hyperoxic-hypercapnic inhalation is a therapeutic option in vascular disorders of the retina. The effect of hyperoxic and/or hypercapnic inhalation on the perfusion of the retina was examined. METHODS: Twenty-five young adults between 18 and 35 years were investigated in a prospective study. They inhaled one of three different mixtures of breathing gases: (1) 100% O2, (2) Carbogen 240 (95% O2 and 5% CO2), (3) 92% O2 with 8% CO2 and were examined by color Doppler imaging of the CRA and OA before and after inhalation. The resistance index (RI) was calculated. RESULTS: The majority of the subjects showed an Increase in the RI in both ophthalmic vessels after inhalation of pure O2, a decrease after breathing in 92% O2 and 8% CO2 and it remained almost constant with inhalation of 95% O2 and 5% CO2. CONCLUSIONS: Inhalation of 92% O2 and 8% CO2 is a possibility for decreasing the peripheral resistance of OA and CRA. No change in blood flow was observed with Carbogen 240.

Adolescent↗
PubMed2002

Impact of laparoscopic gases on peritoneal microenvironment and essential parameters of cell function.

UNLABELLED: Several experimental studies confirm the hypotheses that laparoscopic gases influence the development of tumor metastases [12, 14, 23]. The mechanism for this alteration of malignant tumor growth is still unknown. One reason might be an influence of the in sufflation gas on essential cell function regulating parameters. To investigate the changes of the intra- and extracellular milieu, four parameters--extra- and intracellular pH, intracellular free calcium levels, and tissue oxygen partial pressure--were measured during insufflation with carbon dioxide (CO2), helium (He), or a nonhypoxic gas mixture consistent of 80% CO2 and 20% O2. STUDY DESIGN: (In vitro experiments) Intracellular calcium and pH levels were measured in DHD/K12/TRb colon adenocarcinoma cells using fluorescence imaging microscopy. (In vivo experiments) Tissue oxygen partial pressure was measured using a flexible micro catheter (Licox CMP) implanted in the abdominal wall of rats. After establishing the pneumoperitoneum an optical system and an aspirator were inserted to control the position of the micro catheter and to aspirate wound exudates for pH measurements of the wound fluid. RESULTS: Creating of pneumoperitoneum with both CO2 and helium caused a decrease in partial pressure of oxygen in the abdominal wall to about 5 mm Hg whereas insufflation with a nonhypoxic gas mixture (80% CO2 and 20% O2) induced no significant changes. The intra- and extra cellular pH values dramatically decreased during CO2 insufflation (7.4 to 6.2) in vitro. Helium caused a pH increase up to 7.6. Free intracellular calcium was enhanced during CO2 insufflation, whereas helium insufflation did not cause any changes in [Ca2+]i. Nevertheless, a significant decrease of [Ca2+]i was observed during reoxygenation following helium-induced hypoxia. CONCLUSION: Our study demonstrates that insufflation with either CO2 or He causes significant changes of intra- and extracellular parameters regulating essential cell functions such as oxidative phosphorylation to produce ATP, cell proliferation, or onset of apoptosis.

Acidosis↗
PubMed2001

Liver metastasis following pneumoperitoneum with different gases in a mouse model.

BACKGROUND: The validity of using CO2 in laparoscopic tumor surgery has not yet been established. To address this question, we investigated the growth of liver metastases following insufflation with different gases in a mouse laparoscopy model. METHODS: Male BALB/C mice inoculated intraportally with colon 26 cells were randomized to undergo pneumoperitoneum with CO2 (n = 16), helium (n = 16), argon (n = 16), or air (n = 17), or to act as controls without insufflation (n = 17). RESULTS: The growth of cancer nodules on the liver 14 days after surgery was greater in mice following insufflation with CO2 (p < 0.01), helium (p < 0.01), argon (p = 0.01), and air (p = 0.07) than in control mice. No significant differences were found between the four insufflation groups in the growth of liver metastases. CONCLUSION: These results suggest that insufflation plays an important role in the development of liver metastases but that the choice of gas may not affect their growth.

Analysis of Variance↗
PubMed1987

A computer program for studying blood gases in respiratory care.

We developed a computer program in a style of a game to help study blood gases in respiratory care. The program generates five simulated patients from a pool of 11. The player selects one patient, then the program calculates the patient's condition according to initial condition and selected treatment. Condition of the simulated patient may improve or deteriorate accordingly. Every two hours, the program display the data, requests the diagnosis and asks addition/change of treatment. The program then judges if diagnosis is correct. This process is repeated up to 48 hours. Finally a score and comments are displayed according to the performance of the patient and of the player. Students and young physicians used the original disk 312 times and more than 30 copies are distributed throughout the country. It is useful by itself as a self-teaching tool, but even more useful when combined with verbal teaching by instructors.

Journal Article↗
PubMed1989

Effects of tracheal insufflation of oxygen (TRIO) on blood gases during external cardiac compressions in dogs under ventricular fibrillation.

Tracheal insufflation of oxygen (TRIO) is a form of constant-flow ventilation. We studied the effect of TRIO at a flow rate of 2 L/kg/min on arterial blood gases during external cardiac compressions in dogs with ventricular fibrillation. During the combined application of TRIO and external cardiac compressions, all animals were adequately oxygenated and hyperventilated except in cases where lung edema developed in the course of cardiopulmonary resuscitation (CPR). No pulmonary barotrauma was observed. The findings suggest that TRIO might be used as a temporary measure for emergency ventilation when CPR is performed in certain situations such as upper airway abnormalities or cardiac arrest outside the hospital setting, where intermittent positive pressure ventilation is not feasible.

Journal Article↗
PubMed1975

Arterial blood gases and pH during sleep in chronic obstructive pulmonary disease.

Arterial blood gases were measured during 7 hours of sleep in 15 patients with severe stable chronic obstructive pulmonary discrease (COPD); 6 awake patients with COPD studies in recumbency for an average of 5 hours served as controls. Mean maximal decrease in arterial oxygen partial pressure (PaO2) (plus or minus SD) was 13.5 plus or minus 3.9 mm Hg for sleeping patients (p less than 0.005) and 5.5 plus or minus 1.7 mm Hg for controls (p less than 0.1), respectively. Changes in pH during sleep were of the magnitude expected with acute changes in arterial carbon dioxide partial pressure (PaCO2) in patients with chronic hypercapnia. Consistent changes in heart rate, respiratory frequency or cardiac rhythm were not observed during sleep. Nocturnal worsening of hypoxemia could be explained by alveolar hypoventilation in six sleeping patients and in five controls; in nine sleeping patients, further impariment of ventilation-perfusion mismatch also contributed to worsening of hypoxemia. There was no relationship between the decrease in PaO2 during sleep and the degree of airways obstruction or the PaO2 level when awake. Because of low PaO2, when awake, a fall in PaO2 during sleep brings values into the steep part of the oxyhemoglobin dissociation curve where slight changes in PaO2 result in marked changes in oxygen content. All patients with COPD whose waking PaO2 was below 60 mm Hg had PaO2 below 50 mm Hg during sleep; nocturnal oxygen therapy should be considered in such patients, particularly in the presence of polycythemia or troublesome right-sided heart failure.

Adult↗
PubMed1983

The effect of neuromuscular blockade on oxygen consumption and blood gases in the fetal lamb.

In seven experiments on five chronically monitored fetal lambs (114 to 136 days' gestation), oxygen consumption, umbilical blood flow, and blood gases were measured before and after temporary paralysis of the fetus by the intravenous injection of gallamine. In two of the experiments, breathing movements were absent in the control, pre-gallamine period, and no change in oxygen consumption (VO2) was observed after the drug. In the other five experiments, breathing activity was present in the control period. After gallamine, Vo2 fell by 17%, as a result of a decline in umbilical oxygen extraction; there was no change in umbilical blood flow. In all experiments, umbilical arterial and venous Po2 values rose after paralysis, by 14% and 18%, respectively. The changes in Po2 values are probably secondary to the fall in fetal oxygen consumption. The data indicate that fetal skeletal muscle activity, in the form of breathing activity and perhaps gross body movements, contributes significantly to total fetal oxygen demands. Conversely, cessation of fetal activity in adverse situations, when oxygen supplies are limited, could aid in maximizing the delivery of the available oxygen to vital organs, such as the heart and brain.

Animals↗
PubMed1995

Relationship between placental histologic features and umbilical cord blood gases in preterm gestations.

OBJECTIVE: Our purpose was to test the hypothesis that placental histologic lesions reflect abnormal placental respiratory function in preterm gestations. STUDY DESIGN: A retrospective study of preterm deliveries from 22 to 32 weeks revealed 431 patients with umbilical venous or arterial blood gas values. Excluded were stillbirth, multiple gestations, placenta previa, maternal medical diseases, and fetal anomalies. Charts were reviewed for principal indication of delivery, diagnosis of labor, and mode of delivery. Blood gases were studied within 10 minutes of delivery on a model 178 automatic pH analyzer (Corning Med, Boston). Placental data included uteroplacental vascular lesions and related villous lesions, lesions of acute inflammation, chronic inflammation, and coagulation. Contingency tables and analysis of variance considered p < 0.05 as significant. RESULTS: Mean +/- SD umbilical vein pH was 7.36 +/- 0.07 (range 6.94 to 7.56) and umbilical artery pH was 7.30 +/- 0.08 (range 6.83 to 7.55). Increasing severity of uteroplacental thrombosis, villous lesions reflective of uteroplacental vascular pathologic mechanisms, avascular villi, histologic evidence of abruptio placentae, chronic villitis, and increased circulating erythrocytes were associated with decrease in umbilical vein and artery pH, increase in umbilical vein and artery PCO2, and decrease in umbilical vein and artery PO2. Histologic evidence of acute infection and villous edema were associated with a higher pH and PO2 and a lower PCO2 in both umbilical vein and artery. Umbilical vein or artery base excess was not related to placental lesions. Labor was not related to blood gas values in this data set, although a subset of cases of extremely preterm premature rupture of membranes and preterm labor who labored and were delivered by cesarean section had significantly poorer umbilical venous and fetal arterial blood gas values (all p < 0.005). Lesions related to poorer blood gas values were significantly more frequent in preterm preeclampsia and nonhypertensive abruptio placentae than in premature rupture of membranes or preterm labor. CONCLUSIONS: Changes in umbilical vein and artery pH, PO2, and PCO2 are significantly related to lesions of uteroplacental vascular pathologic mechanisms and intraplacental thrombosis. Placental lesions may be associated with chronic fetal distress by altering fetal oxygen availability and acid-base status. Placental immaturity resulting from prematurity may be associated with inefficient placental respiratory function and an increased likelihood of cesarean delivery in cases of premature rupture of membranes or preterm labor. Altered fetal acid-base balance plus excess numbers of circulating nucleated erythrocytes suggests that placental respiratory function is functionally abnormal when these lesions are present and leads to fetal tissue hypoxia.

Acidosis↗