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Hempleman S C - - 1994
We quantified the neural discharge of intrapulmonary chemoreceptors (IPC) innervating the left lungs of anesthetized Pekin ducks. Right and left lungs were separately unidirectionally ventilated. Alternating steps in CO2 concentration (0-6%, 11-s period) were delivered to the left lung under control conditions [mixed venous PCO2, (PVCO2) 43 +/- 4 Torr] ...
Luz C M - - 1994
Extended laparoscopic operations are being performed increasingly in high-risk patients. To assess the effects of increased intraabdominal pressure (IAP) and positive end-expiratory pressure (PEEP) on the hemodynamic and respiratory system during extended procedures a carbon dioxide pneumoperitoneum was artificially induced in 10 dogs undergoing laparoscopic pelvic lymphadenectomy. An increase in ...
Monge C - - 1994
At the end of incubation, the partial pressures of oxygen and carbon dioxide in the air cell of sea-level avian eggs are similar to those in the expiratory air of adult birds. At high altitude, changes in the permeability of the shell and probably in the embryo metabolism partially compensates ...
White R D - - 1994
STUDY OBJECTIVE: To assess the feasibility and potential usefulness of quantitative measurement of end-tidal carbon dioxide pressure (PETCO2) during out-of-hospital cardiac arrest. DESIGN: Emergency medical technician-paramedics (EMT-Ps) were instructed in the operation of a portable battery-powered capnograph, the sensor for which was attached to the endotracheal tube following intubation. This ...
Sorkine P - - 1994
OBJECTIVE: To evaluate the short-term metabolic and haemodynamic effects of continuous veno-venous haemofiltration (CVVH) in critically ill patients with acute renal failure (ARF). DESIGN: Prospective study of nine consecutive critically ill patients with established acute oliguric renal failure. SETTING: A general ICU in an 800-bed university hospital. PATIENTS: Critically ill ...
Morielli A - - 1993
Pediatric obstructive sleep apnea (OSAS) is characterized by partial airway obstruction, alveolar hypoventilation, and elevated arterial CO2 (PaCO2). Thus, a reliable, practical method of estimating CO2 is needed for pediatric polysomnography. Therefore, we measured both transcutaneous CO2 (PtcCO2) and end-tidal CO2 (PETCO2) in 15 pediatric polysomnographic evaluations. Sleep state, the ...
Bharma S - - 1993
In this study, three series of experiments were conducted on euthermic, anesthetized, artificially ventilated golden mantled ground squirrels (Spermophilus lateralis), each of which altered pHa in a different fashion. In Series I, animals were randomly hypo- or hyper-ventilated. On average, pHa changed from 7.13 to 7.59, PaCO2 from 59.2 to ...
Spahr-Schopfer I A - - 1993
The laryngeal mask airway (LMA), an alternative to tracheal intubation in certain situations, has gained popularity in recent years. Initially designed for use in adults it has now become available in suitable sizes for paediatric anaesthesia. The objectives of this study were to identify the preferred site of sampling the ...
Adamson T P - - 1993
We found conflicting reports regarding the relationship between intrapulmonary PCO2 and sensitivity to PaCO2 in the chicken. To resolve this, we anesthetized eight cockerels with sodium pentobarbital (25-35 mg/kg), cannulated the cutaneous ulnar vein and carotid artery, opened the thorax and ventilated right and left lungs independently. We established PaCO2 ...
Kubota K - - 1993
Respiratory function and hemodynamics were studied during laparoscopic cholecystectomy (LC) under a 10 mmHg pneumoperitoneum (PP) by carbon dioxide insufflation. Blood-gas analysis and measurement of cardiac function by using a Swan-Ganz catheter were performed. Creatinine clearance rate was measured preoperatively and intraoperatively. Compared with values obtained before the institution of ...
Borel C O - - 1993
OBJECTIVE: To test the hypothesis that either decreased ventilatory drive or decreased CO2 responsiveness accounts for the hypoventilation observed in patients during acute ventilatory failure from myasthenia gravis or Guillain-Barré syndrome. DESIGN: Prospective, consecutive case series evaluating trials of ventilatory muscle performance, ventilatory drive, and CO2 response in patients during ...
Dahod S K - - 1993
A silicone tubing probe was used to measure dissolved carbon dioxide in two industrial fermentation processes. The two processes differed markedly in their broth viscosities: one had high viscosity (2000-3000 cP) and the other had low viscosity (< 100 cP). The goal was to study changes in dissolved carbon dioxide ...
Tweed W A - - 1993
We have constructed a simple system for field anaesthesia by using a Farman entrainer and a semi-open circuit to convert a draw-over apparatus to a continuous flow air/O2 system. Compressed O2 was the driving gas for the entrainer; fresh gas (FG) delivered to the semi-open circuit was a mixture of ...
Kotzampassi K - - 1993
The purpose of this experimental study was to determine the hemodynamic conditions of intraperitoneal viscera during pneumoperitoneum by using either CO2 gas or helium (He) for insufflation. In 16 mongrel dogs (divided into a CO2 group and an He group) subjected to 14 mmHg pneumoperitoneum for 60 min, the following ...
Rapoport D M - - 1993
The Bohr/Riley model of CO2 homeostasis describes the relationship between CO2 production, ventilation, and arterial PCO2 and assumes that ventilation and CO2 delivery to the lung are both anatomically and temporally well matched. In contrast to normal breathing, periodic patterns of ventilation show temporal mismatch of ventilation to CO2 delivery. ...
Zhang H - - 1993
Recent reports have suggested that increases in venoarterial difference in PCO2 (VAPCO2) and arteriovenous difference in pH (AVpH) represent valuable markers of tissue hypoxia in shock states associated with low cardiac output. We compared the values of VAPCO2 and AVpH with that of blood lactate in their relationship to changes ...
Morimoto Y - - 1993
OBJECTIVES: To evaluate a) whether end-tidal CO2 values change under constant cardiac output during cardiopulmonary resuscitation (CPR), and b) what factors are responsible for the change. DESIGN: A cohort study. SETTING: University research laboratory. SUBJECTS: Nine mongrel dogs. INTERVENTIONS: Ventricular fibrillation was electrically induced. After 2 mins, open-chest cardiac massage ...
McMahon A J - - 1993
As part of a randomized trial, ventilatory and arterial blood gas changes were assessed during open (n = 30) and laparoscopic (n = 30) cholecystectomy. Measurements were made during anaesthesia before the start of surgery and at the time of removal of the gallbladder. Despite an increase in minute ventilation ...
Christensen P - - 1993
OBJECTIVE: To evaluate the accuracy of a modification of the carbon monoxide method of estimating the circulating blood volume. DESIGN: Prospective, clinical study comparing two methods for estimating the circulating blood volume. Carbon monoxide kinetics were studied by computer simulation. SETTING: Intensive care unit in a university hospital. PATIENTS: Intensive ...
Anderson D - - 1993
Elevated carbon dioxide concentrations frequently encountered in diving operations may have cardiovascular effects. If so, changes in nitrogen loading and elimination may be induced. To study this possibility, whole body nitrogen elimination rates were determined using a rebreathing apparatus and gas chromatographic measurement of N2 in expired gas in six ...
Burke W C - - 1993
Tracheal gas insufflation (TGI) improves the efficiency of CO2 elimination accomplished by conventional mechanical ventilation, primarily by reducing the anatomic (series) dead space volume. Dead space proximal to the catheter tip can be reduced by two methods. Fresh gas introduced at the carinal level during inspiration may effectively "bypass" the ...
Fullerton D A - - 1993
Disturbances of respiratory acid-base status are common in patients supported with mechanical ventilation of the lungs after cardiac operations. This study was conducted with two protocols. The purpose was to determine whether respiratory acid-base status influences pulmonary vascular resistance in adults after cardiac operations and whether the influence is mediated ...
Reeves J T - - 1993
There is considerable variation among individuals in the extent of, and the time required for, ventilatory acclimatization to altitude. Factors related to this variation are unclear. The present study tested whether interindividual variation in preascent ventilation or magnitude of hypoxic ventilatory response related to ventilatory acclimatization to altitude. Measurements in ...
Nahum A - - 1993
Tracheal gas insufflation (TGI) improves the efficiency of CO2 elimination by replacing CO2 in the anatomic dead space proximal to the catheter tip with fresh gas during expiration. Turbulence generated by gas exiting the catheter tip may also contribute to alveolar ventilation. To separate distal (turbulence-related) and proximal (washout of ...
Domino K B - - 1993
We studied the effect of inspired CO2 on ventilation-perfusion (VA/Q) heterogeneity in dogs hyperventilated under two different tidal volume (VT) and respiratory rate conditions with the use of the multiple inert gas elimination technique. Dogs anesthetized with pentobarbital sodium were hyperventilated with an inspired fraction of O2 of 0.21 by ...
Bongard F S - - 1993
Laparoscopic surgical procedures are becoming simultaneously more commonplace and complex. However, carbon dioxide (CO2) pneumoperitoneum required for these procedures causes a respiratory acidosis. We undertook this study to determine if an alternate insufflating gas, such as helium, prevents this sequelae. Twenty patients undergoing elective laparoscopic cholecystectomy were randomized to receive ...
Ho H S - - 1993
BACKGROUND: Carbon dioxide (CO2), the primary gas currently used for pneumoperitoneum, has been known to cause systemic effects on acid-base balance and hemodynamic stability. We studied the hemodynamic effects of CO2 pneumoperitoneum in a hemorrhagic shock model to assess the safety of laparoscopic procedures in acute trauma patients. METHODS: After ...
Nguyen T T - - 1993
The intravenacaval blood gas exchanger (IVOX) developed by Cardiopulmonics, Inc. has been tested in animals and in human clinical trials for partial support of gas exchange (25-30%) to allow reduction in mechanical ventilatory support and barotrauma during acute respiratory failure. After recognizing the limitations of the device and limited clinical ...
Critchley L A - - 1993
Using transthoracic electrical bioimpedance with the BoMed NCCOM3-R7, we measured cardiovascular changes in 16 ASA I and II Chinese patients undergoing laparoscopic cholecystectomy. The peritoneal cavity was insufflated with carbon dioxide to a pressure up to 15 mm Hg. Tidal volume, minute volume and end-tidal carbon dioxide partial pressure were ...
Jones D R - - 1993
Thoracic procedures once requiring open thoracotomy are now being performed with video-assisted thoracoscopy. To visualize adequately the intrathoracic structures, creation of an artificial pneumothorax by carbon dioxide insufflation under positive pressures has been advocated. We hypothesized that positive-pressure insufflation during thorascopy would cause significant hemodynamic compromise. Eight healthy female pigs ...
Cunningham A J - - 1993
We have measured cardiovascular changes associated with insufflation of carbon dioxide and the reverse Trendelenburg position during laparoscopic cholecystectomy, using transoesophageal echocardiography in 13 healthy patients. End-tidal carbon dioxide values increased after insufflation of carbon dioxide, with values significantly (P < 0.05) increased after lateral tilt positioning. Creation of a ...
Leighton T A - - 1993
The recent surge in enthusiasm for laparoscopic surgery has created concern that abdominal insufflation with carbon dioxide produces a respiratory acidosis. This may be because of both transperitoneal gas absorption and impaired ventilation with increased dead space from elevated intraabdominal pressure. To examine the relative contributions of these factors, we ...
Vielle B - - 1993
A model taking into account the cyclic character of respiration in humans is developed using two classical simplifications: CO2 is the only respiratory gas involved; and respiration is regulated only by a CO2 linear controller. The model is used to investigate two important clinical aspects of respiratory disease: asymmetrical ventilation ...
Murciano D - - 1993
Patients with severe chronic obstructive pulmonary disease (COPD) commonly complain of insomnia, but hypnotic drugs are generally not recommended due to their depressant effect on the respiratory centres. The aim of this study was, therefore, to compare the effects of a single dose of the benzodiazepine hypnotics, triazolam 0.25 mg ...
Cox C S CS - - 1993
Initial studies have shown that the intravascular oxygenator and carbon dioxide removal device (IVOX, Cardiopulmonics, Inc., Salt Lake City, UT) removes approximately 30% of VCO2. After noting increased CO2 removal with increased venous CO2, we developed a conceptual analytical model based on data obtained from patients and laboratory experiments. Increasing ...
Wetterberg T - - 1993
Anesthetized, paralyzed and mechanically ventilated pigs were hypoventilated to extreme hypercapnia (PaCO2 approximately 20 kPa) at FiO2 0.5, and allotted to a hypothermic group (31.5 +/- 0.1 degrees C, n = 6) or a control group (39.6 +/- 0.2 degrees C, n = 6). Compared with the controls, the hypothermic ...
Grotzinger J P - - 1993
The Precambrian record of carbonate and evaporite sedimentation is equivocal. In contrast to most previous interpretations, it is possible that Archean, Paleoproterozoic, and to a lesser extent, Meso to Neoproterozoic seawater favored surplus abiotic carbonate precipitation, as aragonite and (hi-Mg?) calcite, in comparison to younger times. Furthermore, gypsum/anhydrite may have ...
Christopherson T J - - 1993
A small number of animal studies have suggested that during the delayed postischemic hypoperfusion state, CO2 reactivity of the cerebral vasculature is lost whereas autoregulation is retained. These findings, however, are inconsistent with the bulk of experimental evidence which demonstrates that CO2 reactivity is more robust and may be retained ...
Wahba R W - - 1993
The purpose of this clinical study was to determine: (1) the increase in minute ventilation required to maintain preinsufflation arterial carbon dioxide tension (PaCO2) during laparoscopic cholecystectomy, and (2) whether end-tidal PCO2 (PETCO2) can be used as an index of PaCO2 and, therefore, of the adequacy of minute ventilation during ...
Kishimoto T - - 1993
A crossover study to compare the effects of seven different dialysers on blood gas conditions during dialysis using acetate-containing dialysate was carried out at five centres in four countries. A significant decrease in pO2 was noted at both 15 and 60 min after the start of dialysis for all dialysers, ...
Aoki A - - 1993
Acid-base status of the blood and tissue fluids and pulmonary gas exchange were continuously observed during intra-abdominal CO2 insufflation for 2 h in 8 paralyzed and artificially ventilated patients who underwent laparoscopic cholecystectomy or resection of the sigmoid colon. Carbon dioxide pressure in the arterial and mixed venous blood as ...
Williams M D - - 1993
Recently we have used the laparoscope to remove the gallbladder in critically ill patients in order to spare them the operative trauma of laparotomy. However, increased intraperitoneal pressure may have deleterious cardiopulmonary effects. This was investigated in a dog model. Insufflation of the abdomen with carbon dioxide decreased the mean ...
Czosnyka M - - 1993
A mathematical model is described that demonstrated the properties of cerebral vascular resistance and compliance expressed as a function of cerebral perfusion pressure (CPP) and arterial CO2 partial pressure (PaCO2). The hypercapnic induced shift of the lower limit of autoregulation to a higher range of CPP, as shown by this ...
Doughty M J - - 1993
The aqueous humors of 100 freshly enucleated rabbit eyes were assessed within 10 min postmortem by taking samples in the last stage of corneal dissection following the Dikstein-Maurice procedure. Aqueous levels of partial pressure of carbon dioxide (pCO2) averaged 58.2 +/- 8.5 mm Hg to give calculated tCO2 and bicarbonate ...
Domino K B - - 1993
BACKGROUND: Hyperventilation frequently is employed to reduce carbon dioxide partial pressure in patients in the operating room and intensive care unit. However the effect of hypocapnia on oxygenation is complex and may result in worsening in patients with preexisting intrapulmonary shunt. To better define the interplay between hypocapnia and oxygenation, ...
Leighton T - - 1992
Hypercarbia occurs during laparoscopy with carbon dioxide (CO2) insufflation. This may be due to increased ventilatory dead space after expansion of the peritoneal cavity with impairment of diaphragmatic excursion, or to increased absorption of CO2 from the peritoneum. To separate these effects, the authors examined the consequences of different insufflating ...
Gavriely N - - 1992
Respiratory insufficiency patients who need only partial ventilatory support are, nevertheless, intubated and connected to a respirator. In search of a partial respiratory assistance method we evaluated the gas exchange, mechanisms, and hemodynamic effects of intratracheal insufflation (ITI) via a narrow (0.2-cm) catheter. The effects of flow rate (0.05-0.2 liter/min ...
Nahum A - - 1992
In the setting of acute lung injury, ventilatory strategies that adjust minute ventilation (VE) to achieve eucapnia often lead to alveolar rupture or damage. Tracheal gas insufflation (TGI) reduces the VE requirements of conventional mechanical ventilation by decreasing the effective dead-space fraction (VD/VT) of each breath. We studied the effect ...
Kiaer T - - 1992
Pathological changes in bone have been related to a preceding impediment of the arterial or venous bone circulation and hypoxia. In this study, we analyzed the feasibility of mass spectrometry in measuring intraosseous oxygen and carbon dioxide. The partial pressures were also measured in intraosseous blood samples, and blood flow ...
Bystritsky A - - 1992
Six panic disorder patients and six matched control subjects were studied using a new technique allowing continuous and simultaneous monitoring of physiological responses (blood pressure, heart rate, respiration) and subjective reports of anxiety and panic. This was done before, during, and after CO2 inhalation. Panic patients had significantly higher variability ...
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