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Results 701 - 750 of 1375
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Domino K B - - 1994
BACKGROUND: Hyperventilation has been recommended to increase blood pH during metabolic acidosis. However, hypocapnia may adversely affect arterial blood oxygenation, especially in the presence of lung disease. We therefore studied the effects of metabolic acidosis, with and without normalization of pH by hyperventilation, on pulmonary gas exchange in dogs with ...
Tobias J D - - 1994
We prospectively examined the cardiorespiratory changes seen with general anesthesia by mask with spontaneous ventilation during brief laparoscopic inspection of the peritoneum in children. Anesthesia consisted of isoflurane in 50% oxygen/air and a caudal epidural block. The patient was allowed to ventilate spontaneously without assistance. Baseline measurements of heart rate, ...
Weissman C - - 1994
OBJECTIVE: To determine the ability of the Puritan-Bennett 7250 metabolic monitor to measure CO2 production and oxygen consumption (VO2) under simulated clinical conditions. DESIGN: An in vitro validation study. SETTING: Laboratory of a large university medical center. METHODS: An in vitro evaluation was performed by adding precise amounts of CO2 ...
Wren K R - - 1994
The use of capnography during general anesthesia has become not only state of the art but also a recommended standard of care. In intubated patients, measurements of partial pressure of carbon dioxide in exhaled pulmonary gases approximate partial pressure of carbon dioxide in arterial blood under stable conditions. End-tidal carbon ...
Porszasz J - - 1994
We evaluated the effect of airflow and gas composition on the linearity of measurement of airflow by a new disposable flowmeter. The flowmeter is based on the principle of differential pressure measurement across two symmetrically disposed Pitot tubes. Nonlinearities arising from the pressure-to-airflow relationship and sensitivity to changes in gas ...
Kuna S T - - 1994
Laryngeal airway resistance (Rlar) was measured in eight normal adult humans during progressive hyperoxic hypercapnia. In most subjects, the translaryngeal pressure-flow relationship appeared linear under normocapnic conditions. During hypercapnia, the pressure-flow relationship on inspiration and expiration was curvilinear with increasing translaryngeal pressure associated with progressively smaller increments in flow. Translaryngeal ...
Shibutani K - - 1994
In anesthetized patients, acute decreases in cardiac output (CO) are often reflected as decreases in end-tidal CO2 tension (PETCO2), but the quantitative relationship between the changes in CO and the changes in PETCO2 is uncertain. We hypothesize that a quantitative relationship can be demonstrated if timing of the measurements in ...
Wheeler R M - - 1994
Soybean and potato plants were grown in controlled environments at carbon dioxide (CO2) partial pressures ranging from 0.05 to 1.00 kPa. The highest yields of edible biomass occurred at 0.10 kPa for both species, with higher CO2 levels being supraoptimal, but not injurious to the plants. Stomatal conductance rates of ...
Couture P - - 1994
We evaluated the effects of CO2 embolism on end-tidal carbon dioxide (ETCO2) and compared four methods for detection of gas embolism. Fourteen pigs were monitored for CO2 embolism with transesophageal echocardiography (TEE), changes in ETCO2, changes in mean pulmonary artery pressure (MPAP), and precordial auscultation (AUSC). Serial injections of CO2 ...
Adamson T P - - 1994
Intrapulmonary chemoreceptors (IPC) and extrapulmonary afferents (EPA) have been shown to interact in ventilatory control in the chicken. It is not clear, however, if all or only some of the EPA are involved in this interaction with IPC. We therefore designed this study to determine if afferents carried in the ...
Chang D T - - 1994
Oliguria is infrequently viewed as a complication of laparoscopic surgery. The rate of urine output in six healthy patients undergoing laparoscopic surgery was measured during the period of CO2 pneumoperitoneum and for several hours after desufflation. The average hourly urine output during insufflation was 0.30 +/- 0.14 mL/kg despite an ...
Esper E - - 1994
Carbon dioxide pneumoperitoneum (PP) during laparoscopic cholecystectomy (LC) causes hypercapnia and acidemia. Thermocautery carbon monoxide formation during LC was studied in 15 patients. CO samples were read by electrochemical sensor as parts per million (ppm) and obtained intraperitoneally at PP, gallbladder takedown (GBTD), and exhalation. In blood, CO was measured ...
Baraka A - - 1994
An investigation was carried out on 13 ASA class 1 or 2 adult patients undergoing laparoscopic cholecystectomy. Throughout laparoscopy, the end-tidal PCO2 was continuously monitored by capnography and the arterial hemoglobin oxygen saturation by pulse oximetry. Also, repeated measurements of arterial blood gases were done. Ventilation was controlled using an ...
Nyarwaya J B - - 1994
Cardiorespiratory changes induced by pneumoperitoneum and head-up tilt may generate alveolar ventilation to perfusion ratio changes and increased systemic vascular resistances. The reliability of end-tidal carbon dioxide tension and pulse oximetry in predicting arterial carbon dioxide partial pressure and arterial oxygen saturation may therefore be affected. The 35 ASA 1-2 ...
Graham A J - - 1994
Adult intraabdominal surgery performed with the minimal-access technique has created a revolution in surgery. This technique has remained largely unused for pediatric surgical procedures because of concerns regarding its safety and efficacy. Presently, intraabdominal insufflation of CO2 is the preliminary step to performing minimal access surgery. In this study, an ...
Lunkenheimer P P - - 1994
OBJECTIVE: Controversy exists as to whether high-frequency oscillatory ventilation can be used on babies and small laboratory animals only, or whether high-frequency oscillatory ventilation can also be efficient in the adult patient and large (> 65 kg body weight) laboratory animals. Moreover, controversy exists as to whether limitations in high-frequency ...
Bremner P - - 1994
BACKGROUND: The reason for the increased risk of death with fenoterol and isoproterenol in asthma is unknown but may relate to their cardiovascular effects. Deaths from asthma usually occur outside hospital where hypoxemia, with or without hypercapnia, may exist. Both of these states can influence the cardiovascular system. We investigated ...
Morimoto Y - - 1994
The present study was designed to determine whether lactate changes the critical pH point at which the recovery of rat population spike is inhibited following glucose-oxygen deprivation and second, which degree of lactic acidosis is similar to the effect of CO2 acidosis. The population spike was recorded from the hippocampal ...
Liem T - - 1994
Laparoscopic procedures requiring abdominal CO2 insufflation are applied with increasing frequency to the pediatric age group. Whereas the physiological effects accompanying insufflation have been studied in laboratory and clinical adult subjects, little is known of these effects in the juvenile subject. Young swine (weight, 10 to 12 kg, approximate age, ...
Lee T S - - 1994
Acetazolamide, a carbonic anhydrase inhibitor, may cause significant disturbances in carbon dioxide transport and elimination. In this study, end-tidal carbon dioxide monitoring has been used to study the correlation between arterial carbon dioxide (PaCO2) and end-tidal carbon dioxide partial pressure (PE'CO2) in rabbits treated with acetazolamide. A significant difference in ...
Sanders M H - - 1994
STUDY OBJECTIVE: Although it is intuitively desirable, the measurement of arterial carbon dioxide tension (PaCO2) during diagnostic polysomnography and nocturnal trials of positive pressure therapy is invasive and potentially expensive. The accuracy of end-tidal carbon dioxide tension (PETCO2) and transcutaneous carbon dioxide (tcPCO2) monitoring in these contexts has not been ...
Uchiyama T - - 1994
We examined whether pyridoxalated hemoglobin-polyoxyethylene conjugate (PHP) could be life-relievable for carbon monoxide (CO) intoxication. Toxic gas (O2, 5.0%; CO2, 16.0%; CO, 1.8%; and N2, 77.2%) was inhaled by rabbits anesthetized with urethane and the following parameters were measured: blood pressure, arterial and venous Po2, Pco2, pH, and carboxyhemoglobin (COHb). ...
Wolfer R S - - 1994
As more complex thoracoscopic procedures are performed, adequate exposure becomes increasingly more important. The insufflation of CO2 has been demonstrated to aid in the compression of lung parenchyma and the effacement of subpleural lesions, and to act as a retractor when combined with changes in patient position. However, a recent ...
Linér M H - - 1994
Alveolar gas exchange was studied in 11 submerged subjects during and after 75-s breath holds with or without a transient increase of ambient pressure to 3 ATA (20 msw). During surface breath holds (SBH), cardiac index fell to 73% of eupneic control but was partially restored at depth to 88% ...
Scheid P - - 1994
To investigate ventilatory CO2 sensitivity during inspiratory pressure support (IPS), we administered inspiratory CO2 [fractional concn (FICO2) 0.01, 0.03, or 0.05] in eight normal subjects without (CTRL) or with (Pinsp) positive inspiratory airway pressure (5 or 10 cmH2O). At CTRL and low IPS, CO2 inhalation led to a significant increase ...
McMahon A J - - 1994
Laparoscopic cholecystectomy with carbon dioxide pneumoperitoneum may result in hypercarbia and acidosis in patients with cardiorespiratory disease. The aim of the present study was to assess helium as an alternative to carbon dioxide for creating the pneumoperitoneum. Ventilation requirements and carbon dioxide levels were assessed at the beginning and end ...
Zwischenberger J B - - 1994
IVOX (intravenous oxygenator and CO2 removal device) augments venous gas exchange in patients with severe respiratory failure. Controlled hypoventilation with permissive hypercapnia reduces airway pressures during mechanical ventilation and augments CO2 exchange through the IVOX. To quantify the additive effects of gradual permissive hypercapnia and IVOX on gas exchange and ...
Otto K - - 1994
Changes in cardiopulmonary function and platelet count were determined in 22 dogs of various breeds that underwent total hip replacement with cemented femoral prostheses. In 11 dogs (group I) polymethylmethacrylate (PMMA) was inserted without venting the reamed and lavaged femoral canal. In a second group of 11 dogs (group II) ...
Rademaker B M - - 1994
We studied the haemodynamic effects of intra-abdominal insufflation with either CO2 (n = 15) or N2O (n = 15) in patients undergoing laparoscopic surgery. Haemodynamic variables were measured at increasing levels of intra-abdominal pressure up to 20 mmHg. In the CO2 group cardiac index decreased from 2.6 +/- 0.6 to ...
Sato M - - 1994
Hypoxic ventilatory response (HVR) and hypoxic ventilatory depression (HVD) were measured in six subjects before, during, and after 12 days at 3,810-m altitude (barometric pressure approximately 488 Torr) with and without 15 min of preoxygenation. HVR was tested by 5-min isocapnic steps to 75% arterial O2 saturation measured by pulse ...
Swenson E R - - 1994
We studied the effect of low concentrations (2 to 4%) of inspired CO2 on gas exchange and ventilation-perfusion (VA/Q) relationships in healthy normocapnic anesthetized dogs during constant mechanical ventilation by the multiple inert gas elimination technique (MIGET). One group was studied at normal tidal volumes (12 to 14 ml/kg) and ...
Gardner W - - 1994
This article describes the basic principles of the measurement of end-tidal carbon dioxide (CO2) and oxygen (O2) in humans. The description includes definitions of the major parameters of breathing (e.g., the composition of atmospheric air, arterial and venous blood; metabolism; lung capacity; volumetric measures of tidal volume, minute volume, and ...
Ghosh T K - - 1994
Effects of intralaryngeal CO2 on the response of superior laryngeal afferents to negative pressure were investigated in 20 anesthetized spontaneously breathing adult cats. Single-fiber action potentials were recorded from the peripheral cut end of the superior laryngeal nerve. The larynx was exposed to negative pressure during inspiration when the animal ...
Pillunat L E - - 1994
The vascular reactivity to breathing carbon dioxide represents a widely used method in neurology to diagnose microvascular cerebral disorders. Fifteen eyes of 15 patients suffering from confirmed normal pressure glaucoma were included in the study. The ocular carbon dioxide reactivity was determined by recording ocular pulse amplitudes (OPA) by means ...
Pearson M R - - 1994
We measured plasma potassium concentrations in five anaesthetized pigs over a 3.5 h period during which a carbon dioxide pneumoperitoneum was maintained. During this period the abdominal pressure was kept at 1.96 kPa and normocapnia was maintained by intermittent positive pressure ventilation. The potassium concentration was found to increase with ...
Warren D W - - 1994
OBJECTIVES: To examine: a) the rate and extent of delivery of radioactive tracers to the central circulation from the tibial, medial malleolar, distal femoral, and humeral intraosseous sites, as well as from a peripheral intravenous site; and b) the end-tidal CO2 response to injected sodium bicarbonate at these sites. DESIGN: ...
Bongard F - - 1994
Postoperative respiratory monitoring of surgical patients requires assessment of both oxygenation and ventilation. Arterial blood gas (ABG) measurements traditionally have been used to detect elevated arterial carbon dioxide (PaCO2) concentrations. The recent availability of a noninvasive technique for end-tidal CO2 measurements (EtCO2) may allow substitution of this real-time modality for ...
Kohshi K - - 1994
We have studied how in situ arterial (PaCO2) and brain tissue PCO2 (PbCO2) responses to acetazolamide (AZ) are affected by respiratory patterns. Sixteen cats were anesthetized with ketamine. Group 1 cats (n = 7) breathed air spontaneously. Group 2 cats (n = 6) were paralyzed and ventilated mechanically to maintain ...
Watt J W - - 1994
Transcutaneous blood gases were recorded for 60 min when awake and asleep in 10 ventilator-dependent patients with high tetraplegia who used a pressure-limited ventilator and uncuffed tracheostomy tube. The mean arterial oxygen tension awake was 16.0 kPa compared with 15.2 kPa when asleep; the mean arterial carbon dioxide tension awake ...
Baraka A - - 1994
An investigation of end-tidal carbon dioxide tension changes was carried out in 19 healthy adult patients undergoing laparoscopic cholecystectomy. Following induction of anaesthesia, and throughout surgery, the end-tidal carbon dioxide tension was continuously monitored by capnography. The value following carbon dioxide insufflation increased with time to reach a maximum value ...
Eisenhauer D M - - 1994
The hemodynamic effects of argon pneumoperitoneum were studied to define its possible role as an alternative gas for intraperitoneal insufflation during minimally invasive surgery. Adult pigs were anesthetized and placed on mechanical ventilation. Parameters measured or determined included mean arterial (MAP), pulmonary arterial (PAP), pulmonary arterial wedge (PAWP), right atrial ...
Smith L J - - 1994
Quantitative electroencephalography was assessed in 6 dogs anesthetized with 1.8% end-tidal halothane, under conditions of eucapnia, hypocapnia, and hypercapnia. Ventilation was controlled in each condition. Heart rate, arterial blood pressure, core body temperature, arterial pH, blood gas tensions, end-tidal CO2 tension, and end-tidal halothane concentration were monitored throughout the study. ...
Bach J R - - 1994
The purpose of this study was to determine longitudinal changes in nocturnal blood gas tensions in individuals with stable traumatic tetraplegia. Ten individuals initially evaluated at least 6 months postinjury were reevaluated 5 years later. When initially evaluated, all the patients had normal daytime blood gases. Six (60%), however, had ...
Russell G B - - 1994
The accuracy and reliability of the relationship between arterial and end-tidal carbon dioxide (PETCO2 and PaCO2), expressed as the gradient, P(a-ET)CO2, was assessed with 171 comparisons in nine mechanically ventilated trauma patients. The P(a-ET)CO2 was 14 +/- 11 mm Hg. (mean +/- standard deviation.) The positive correlation between PaCO2 (44 ...
Hopper A O - - 1994
End-tidal PCO2 (PETCO2) measurements from two commercially available neonatal infrared capnometers with different sampling systems and a mass spectrometer were compared with arterial PCO2 (PaCO2) to determine whether the former could predict the latter in mechanically ventilated rabbits with and without lung injury. The effects of tidal volume, ventilator frequency ...
Hill R C - - 1994
Goats (N = 7) were decompressed from 1,500 m to 9,150, 9,750, or 10,400 m simulated altitude while breathing CO2 tensions of 0, 15, 30, or 46 mm Hg in O2 during 15-min prebreathing and 30-min peak altitude exposures. Risk of decompression sickness was determined by detecting venous gas emboli ...
Maeda H - - 1994
OBJECTIVE: To evaluate hypertensive cerebral involvement before cerebrovascular accidents. DESIGN: Cerebral microvascular responses to changes in the arterial partial pressure of CO2 (pCO2; the CO2 reactivity) were compared among patients with different stages and severity of hypertensive disease. PATIENTS: Fifty-eight patients with hypertension, 11 with borderline hypertension, 15 hypertensives with ...
Benton B J - - 1994
Reversal of saxitoxin (STX; 10 micrograms/kg, ip) induced cardiorespiratory effects by oxygen ventilation and burro-raised alpha-STX antitoxin (60 mg/kg, i.v.) was studied in urethane-anesthetized guinea pigs acutely instrumented for concurrent monitoring of medullary respiratory-related single units, diaphragm EMG, Lead II electrocardiogram, arterial blood pressure (BP), arterial pH, and O2/CO2 tensions, ...
Lister D R - - 1994
BACKGROUND: Carbon dioxide absorption into the blood during laparoscopic surgery using intraperitoneal carbon dioxide insufflation may lead to respiratory acidosis, increased ventilation requirements, and possible serious cardiovascular compromise. The relationship between increased carbon dioxide excretion (VCO2) and intraperitoneal carbon dioxide insufflation pressure has not been well defined. METHODS: In 12 ...
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] ...
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