Search Results
Results 551 - 600 of 1378
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Levine R L - - 1997
BACKGROUND: Survival after cardiac arrest occurring outside the hospital averages less than 3 percent. Unfortunately, the outcome of prolonged resuscitative attempts cannot be predicted. End-tidal carbon dioxide levels reflect cardiac output during cardiopulmonary resuscitation. We prospectively determined whether death could be predicted by monitoring end-tidal carbon dioxide during resuscitation after ...
Kreutzer C - - 1997
In this study we report the results of the use of a closed hood with no external administration of CO2 to increase pulmonary vascular resistance by lowering the inspired fraction of oxygen (FiO2) and raising the inspired fraction of carbon dioxide (FiCO2) in patients with congenital heart disease and increased ...
Heyer L - - 1997
The aim of this study was to compare the effect of inspiratory pressure support (IPS) on the respiratory CO2 response in 13 stable COPD patients and in 13 normal subjects. Without IPS, the slopes of the ventilatory response to CO2 were lower in the patients than in the normal subjects ...
Tantucci C - - 1997
To investigate the effects of the autonomic nervous system on control of breathing, the neuromuscular (mouth occlusion pressure at 0.1 s after onset of inspiration [P0.1]) and ventilatory (minute ventilation [VE]) response to progressive hyperoxic hypercapnia was assessed in diabetic patients with autonomic dysfunction of different severity. Eighteen diabetics with ...
Gomersall C D - - 1997
Splanchnic ischaemia is thought to be of central importance in the development of multi-organ failure and hence death in critically ill patients. It has been suggested that the arterial to gastric intramucosal pH gradient and the difference in partial pressure of carbon dioxide between gastric mucosa and arterial blood are ...
Meyer K - - 1997
Eleven men with severe chronic heart failure (peak cardiac index 4.0 +/- 0.2 L/m2/min), six on a heart transplantation waiting list, were prospectively assessed. To determine reproducibility of cardiopulmonary and hemodynamic variables for clinical purposes during ramp bicycle ergometry, the patients underwent two ramp bicycle ergometer tests (3 minutes unloaded, ...
Enomoto A - - 1997
In order to elucidate the sterilization mechanism underlying the explosive decompression system, baker's yeast was pressurized with CO2, N2O, N2, or Ar gas at 40 atm and 40 degrees C for 4h, and then explosively discharged. The survival ratio was markedly decreased only by the treatments with CO2 and N2O, ...
Abramo T J - - 1997
OBJECTIVE: To determine the reliability and clinical value of end-tidal CO2 by oral/nasal capnometry for monitoring pediatric patients presenting post ictal or with active seizures. DESIGN: Clinical, prospective, observational study. SETTING: University affiliated children's hospital. INTERVENTIONS: One hundred sixty-six patients (105 patients with active seizures, 61 post ictal patients) had ...
Meijer D W - - 1997
BACKGROUND: Disadvantages related to CO2 pneumoperitoneum have led to development of the abdominal wall retractor (AWR), a device designed to facilitate laparoscopic surgery without conventional pneumoperitoneum (15 mmHg CO2). We investigated the effects of the AWR on hemodynamics and gas exchange in humans. We also investigated whether the use of ...
McArthur C - - 1997
Indirect calorimetry can be a useful tool to define nutritional status, determine nutritional requirements, and assess response to nutritional interventions. Measurements of oxygen consumption and carbon dioxide production may be used to determine cardiac output and work of breathing, and estimate the components of minute ventilation. An understanding of the ...
Berkenbosch A - - 1997
BACKGROUND: The ventilatory response to hypoxia is composed of the stimulatory activity from peripheral chemoreceptors and a depressant effect from within the central nervous system. Morphine induces respiratory depression by affecting the peripheral and central carbon dioxide chemoreflex loops. There are only few reports on its effect on the hypoxic ...
Casati A - - 1997
METHODS: One hundred and five ASA I-II patients, scheduled for elective surgical procedures were studied in order to evaluate the effect of different surgical postures on physiological pulmonary dead space (VDphys/ VT) and arterial to end-tidal carbon dioxide gradient [P(a-Et)CO2]. Patients were divided into four groups according to their position ...
Georgopoulos D - - 1997
Inspiratory muscle output is downregulated when the mechanical load is reduced in awake humans. It is not known whether this is related to reduction in PCO2 or to removal of load-related neural responses. To address this issue, we did Read CO2 rebreathing tests in 13 normal subjects with and without ...
Okamoto K - - 1997
STUDY OBJECTIVE: We hypothesized that the continuous gas flow administration delivered through an insufflation catheter positioned above the carina during airway pressure release ventilation (APRV) would facilitate carbon dioxide (CO2) elimination, resulting in normocarbia with a substantially reduced peak airway pressure (Paw). To test this hypothesis, we compared intermittent positive ...
Schilling M K - - 1997
BACKGROUND: Splanchnic macrocirculatory changes during high-pressure CO2 pneumoperitoneum include a decrease in mesenteric arterial blood flow, and decreased gastric perfusion with a drop in gastric pH in experimental studies. Microcirculatory changes in abdominal organs under clinical conditions with a low pressure CO2 pneumoperitoneum are unknown. STUDY DESIGN: In 18 patients ...
Wallace D H - - 1997
BACKGROUND: The factors affecting cardiorespiratory changes and postoperative pain after laparoscopic cholecystectomy are poorly understood. The aim of this study was to assess these changes in patients undergoing laparoscopic cholecystectomy at an insufflation pressure of 7.5 or 15 mmHg. METHODS: Forty patients with similar preoperative characteristics were randomized, 20 to ...
Tao W - - 1997
OBJECTIVES: To quantify CO2 removal using an extracorporeal low-resistance membrane gas exchanger placed in an arteriovenous shunt and evaluate its effects on the reduction of ventilatory volumes and airway pressures during severe respiratory failure induced by smoke inhalation injury. DESIGN: Prospective study. SETTING: Research laboratory. SUBJECTS: Adult female sheep (n ...
Roberts M W - - 1997
BACKGROUND: Carbon dioxide is the current gas of choice for pneumoperitoneum, but hemodynamic and acid-base effects secondary to its systemic absorption have been reported. Various studies have suggested inert gases as alternatives. METHODS: We studied the cardiopulmonary responses to intravenous infusion of carbon dioxide, nitrous oxide, argon, helium, and nitrogen ...
Zollinger A - - 1997
Arterial blood gases were studied prospectively using continuous intraarterial blood gas monitoring during thoracoscopic volume reduction surgery (VRS) in 24 patients with advanced diffuse pulmonary emphysema. Additionally, the early postoperative course (48 h) of arterial blood gases was studied retrospectively. Twenty-six operations were performed using a combination of thoracic epidural ...
Hamilton-Davies C - - 1997
OBJECTIVE: The gastrointestinal tonometer, which allows measurement of gastrointestinal mucosal CO2 and subsequent derivation of gut intramucosal pH (pHi), has been demonstrated to be a sensitive predictor of outcome following major surgery. Current theory suggests that the origin of the low pH may be hypovolaemia. This study was designed to ...
Junghans T - - 1997
OBJECTIVE: To evaluate the effects of pneumoperitoneum with carbon dioxide, argon, and helium; different abdominal pressures (ie, 8, 12, and 16 mm Hg); and different positions (ie, head up, head down, supine) on hemodynamic and respiratory function in a porcine model. DESIGN: Prospective randomized trial. SETTING: Animal research laboratory. ANIMALS: ...
Giebler R M - - 1997
Both retroperitoneoscopic and laparoscopic surgical approaches to kidney and adrenal gland have been reported but their cardiopulmonary pathophysiology has been incompletely characterized. To test the hypothesis that these approaches have markedly different impact on the circulatory and respiratory systems, we assessed at similar insufflation pressures alterations in cardiovascular and respiratory ...
Fleming R Y - - 1997
BACKGROUND: A search for alternative methods of abdominal insufflation has been prompted by the fact that CO2 insufflation may cause acidosis, decreased cardiac output, increased systemic vascular resistance, and increased cardiac filling pressures. This study evaluates the safety and the cardiopulmonary effects of helium abdominal insufflation (HAI). METHODS: Thirteen ASA ...
Voipio J - - 1997
1. CO2-H(+)-sensitive microelectrodes were used for simultaneous measurements of the partial pressure of CO2 (PCO2) and extracellular pH (pHo) in the ventral respiratory group (VRG) of the isolated brainstem-spinal cord of neonatal rats. Some of the data were analysed using diffusion equations. 2. With increasing recording depth within the boundaries ...
Hoffman W E - - 1997
OBJECTIVE: The purpose of this study was to determine whether baseline partial pressure of oxygen (PO2), partial carbon dioxide pressure (PCO2), and pH in brain tissue adjacent to arteriovenous malformations (AVMs) are different from those in control patients. In addition, PO2, PCO2, and pH changes were measured during resection of ...
Westfelt U N - - 1997
BACKGROUND: Because of the potential toxicity of nitric oxide (NO) and its oxidising product nitrogen dioxide (NO2), any system for the delivery of inhaled NO must aim at stable and predictable levels of NO and as low concentrations as possible of NO2. METHODS: In a laboratory set-up, we have evaluated ...
Rapanos T - - 1997
The ventilatory response to acute progressive hypoxia below the carbon dioxide threshold using rebreathing was investigated. Nine subjects rebreathed after 5 min of hyperventilation to lower carbon dioxide stores. The rebreathing bag initially contained enough carbon dioxide to equilibrate alveolar and arterial partial pressures of carbon dioxide to the lowered ...
Quaranta A J - - 1997
Cheyne-Stokes respiration (CSR) is a form of sleep-disordered breathing seen in approximately 40% of congestive heart failure patients with a left ventricular ejection fraction of < 40%. It is characterized by a crescendo-decrescendo alteration in tidal volume separated by periods of apnea or hypopnea. Sleep is generally disrupted, often with ...
Ferzli G S - - 1997
Pneumothorax was identified as a complication of endoscopic hernia repair in two patients with insufflation pressures of 15 mmHg and operating times exceeding 2 h. These patients also showed intraoperative perturbations in both oxygen saturation and end-tidal CO2 production. A prospective study was undertaken to determine whether similar complications would ...
Mann C - - 1997
BACKGROUND: The aim of the study was to compare the value of transesophageal Doppler and end-tidal carbon dioxide monitoring to detect venous carbon dioxide embolism in pigs during laparoscopic cholecystectomy. METHOD: Ten pigs were anesthetized under constant ventilation, and instrumented for laparoscopic cholecystectomy. CO2 pneumoperitoneum was performed at 15 mmHg ...
Rogers G G - - 1997
We investigated the reproducibility of the carbon dioxide (CO2) rebreathing extrapolation technique of Defares to determine the mixed venous partial pressure of CO2 (PvCO2) using a direct, rather than the commonly used indirect, extrapolation method. The PvCO2 determinations were made five times a day on four subjects who exercised for ...
Chhibber A K - - 1997
The laryngeal mask airway (LMA) has become a popular tool for airway management in selected adult and pediatric patients undergoing routine surgical procedures. The relationship between end-tidal and arterial carbon dioxide during controlled ventilation via the LMA in infants under 10 kg has not been reported. After induction of general ...
Corey K A - - 1997
A 34-day functional test was conducted in Johnson Space Center's Variable Pressure Growth Chamber (VPGC) to determine responses of a wheat stand to reduced pressure (70 kPa) and modified partial pressures of carbon dioxide and oxygen. Reduced pressure episodes were generally six to seven hours in duration, were conducted at ...
Corey K A - - 1997
The variable pressure growth chamber (VPGC) was used in a 34-day functional test to grow a wheat crop using reduced pressure (70 kPa) episodes totalling 131 hours. Primary goals of the test were to verify facility and subsystem performance at 70 kPa and to determine responses of a wheat stand ...
Fukuda K - - 1997
When using a nasal cannula to sample gases expired by a patient, air from the room may dilute the sample. For this reason, the accuracy of the partial pressure of end-tidal carbon dioxide (ETCO2) measurements is questionable. We experimentally examined the reliability of ETCO2 measurements through a nasal cannula and ...
Cruz A M - - 1996
BACKGROUND: Laparoscopic surgical procedures are being performed in pregnant women with increasing frequency. Maternal-fetal physiologic changes occurring during intraabdominal carbon dioxide insufflation are poorly understood, and maternal-fetal safety is of concern during carbon dioxide pneumoperitoneum. A previous pilot study using end-tidal carbon dioxide-guided ventilation resulted in maternal and fetal acidosis ...
Jolliffe M P - - 1996
An abrupt decrease in end-tidal carbon dioxide (CO2) occurred in an anesthetized male who was placed in the head down position during radical perineal prostatectomy. The end-tidal CO2 was restored after insertion of a wet pack into the operative site, which strongly indicated venous air embolism as the cause. Predisposing ...
Yavari P - - 1996
Stimulation of the upper respiratory tract with air-borne irritants can result in dramatic alterations of cardiorespiratory rhythms that include apnea, bradycardia and selective peripheral vasoconstriction. Since carbon dioxide can stimulate receptors in the nasal passages, we wanted to determine if this odorless gas can induce the same autonomic changes as ...
Steiger H J - - 1996
BACKGROUND AND PURPOSE: Both ischemia and hyperperfusion are known phenomena that follow traumatic brain injury. Cerebral carbon dioxide reactivity is diminished in both conditions. Differentiation is important because ischemia is thought to be a major factor of secondary neuronal loss and is potentially amenable to therapy by manipulation of cerebral ...
Roupie E E - - 1996
OBJECTIVE: To evaluate the clinical performance of a new, continuous intra-arterial blood gas monitoring system (CIABG) in abnormal ranges of blood gases, and during episodes of low blood pressure, in critically ill patients. DESIGN: Prospective study. SETTINGS: Medical ICU, University Hospital. METHODS: The CIABG system, based on fluorescent dyes, consists ...
Schäublin J - - 1996
We have examined a new approach, using fuzzy logic, to the closed-loop feedback control of mechanical ventilation during general anaesthesia. This control system automatically adjusts ventilatory frequency (f) and tidal volume (VT) in order to achieve and maintain the end-tidal carbon dioxide fraction (FE'CO2) at a desired level (set-point). The ...
Hoffman W E - - 1996
We tested whether cerebral arteriovenous malformations (AVM) alter brain tissue oxygen pressure, PO2, carbon dioxide pressure PCO2, and pH before, during, and after hypercapnia. A craniotomy was performed and a sensor inserted into normal brain tissue (control) (n = 7) or into tissue adjacent to an AVM (n = 9). ...
Gowski D T - - 1996
New management options for acute respiratory failure aim at avoiding ventilator-induced lung injury while maintaining adequate gas exchange. Selected approaches examined in this article include methods to augment carbon dioxide elimination with tracheal gas insufflation, venovenous extracorporeal carbon dioxide removal, and intravascular oxygenation. Improving oxygenation can be accomplished by judicious ...
Clancy J - - 1996
Respiratory homeostasis is concerned with the regulation of a blood gas composition that is compatible with maintaining cellular homeostasis. Provided that the lung-capillary exchange barrier does not prevent the exchange of gases, then blood leaving the lung will have oxygen and carbon dioxide partial pressures that are similar to the ...
Desmecht D J - - 1996
To explore the pathophysiology of respiratory failure in an experimental pneumonia, a Pasteurella haemolytica broth culture was injected intratracheally into 12 calves, which were then studied over a period of 10 h. Measurements were made of inspired minute ventilation (VE), ventilatory pattern [inspiratory time (TI), expiratory time (TE), respiratory rate ...
Marathe U S - - 1996
BACKGROUND: Carbon dioxide (CO2) pneumoperitoneum has been shown to adversely affect hemodynamics in patients. This study specifically examines the potential contribution of altered left ventricular contractility (LVC) to hemodynamic changes observed during CO2 pneumoperitoneum. METHODS: In a canine model, LV volumes, LV pressure, and intrathoracic and central venous pressures were ...
Wilson R F - - 1996
BACKGROUND: To determine the relationship between the prognosis of seriously injured patients requiring emergency surgery and intraoperative end-tidal CO2 variables and "excess Pco2." METHOD: Retrospective chart review of 100 seriously injured patients admitted to Detroit Receiving Hospital and requiring major surgery (mortality rate of 40%). Standard intraoperative monitoring, including continuous ...
Arnold J H - - 1996
OBJECTIVE: To examine the utility of single breath CO2 analysis as a noninvasive measure of cardiac output. SETTING: An animal laboratory in a university-affiliated medical center. DESIGN: A prospective, animal cohort study comparing 21 parameters derived from single breath CO2 analysis with cardiac output determined by an ultrasonic flow probe. ...
Ortega A E - - 1996
BACKGROUND: The effects of carbon dioxide pneumoperitoneum on venous return and cardiac hemodynamics during laparoscopic surgery were studied. METHODS: Twelve adult pigs underwent placement of an electromagnetic flow meter across the infrarenal vena cava (IVC) as well as placement of Swan Ganz and arterial monitoring catheters. Measurements of the flow ...
Schöb O M - - 1996
BACKGROUND: Previous studies have suggested that diagnostic laparoscopy may be contraindicated in multiple trauma patients with closed head injuries because of the detrimental effects of carbon dioxide (CO2) pneumoperitoneum on intracranial pressure (ICP). In this study we compared the effects of two alternative inflation gases, helium (He) and nitrous oxide ...
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