The effect of partial pressure of isoflurane on its solubility in blood of different haematocrit was determined at different isoflurane partial pressures, using a syringe--flask method and gas chromatography with blood from one donor. The solubility of isoflurane decreased with increasing blood haematocrit (39.5%, 51.9% and 61.9%) and isoflurane partial ...

In this study we have investigated the effects of breath holding and of the physical properties of gases on four different respiratory dead spaces (VD): the Fowler, the physiological, the washout and the inert gas dead space. The experiments were performed with dogs which were ventilated artificially with breathing patterns ...

Laboratory-based blood gas analyzers have reliably produced pH, PCO2, and PO2 analyses for several decades. Over this time, their design changes reduced maintenance procedures, microprocessor-controlled functions simplified operation, and regulations governing their use have expanded. This article presents the electrochemical principles of the pH and blood gas electrodes and the ...

We have examined the predictability of inspired isoflurane concentration during low-flow anaesthesia using a to-and-fro breathing system. Twenty one adult patients requiring mechanical ventilation of the lungs during surgery took part in this study. Using a fresh gas flow of 2 l.min-1, the ratio of inspired isoflurane concentration to isoflurane ...

A 46-year-old man with schizophrenia, died in hospital. Autopsy revealed numerous facial injuries and the direct cause of death was apparently asphyxia as a large amount of coagulated blood was present in the lower part of the trachea and bronchi. The blood derived from a lacerated wound of the mouth. ...

Argon, CO2, and N2 gasses were each evaluated in a broiler chicken gas killing system. Birds were killed by individual exposure to one of the three gasses for 2 min in a flow-through system. The gasses were evaluated by determining the time, in seconds, for the following responses: first reaction ...

Hypothermia is a common postsurgical problem, yet information documenting the impact of laparoscopy on perioperative heat balance is scarce. This paper quantifies the changes in core temperature over a 3-h period of high-flow CO2 insufflation in a randomized, controlled trial of six pigs. Each animal was anesthetized and studied on ...

In the present study we evaluated the occupational exposure to N2O and isoflurane during open circuit (OC) (fresh gas flow > or = minute volume) and low flow (LF) (fresh gas flow = 1.5 l/min) anaesthesia. The effects of active scavenging and of a charcoal filter positioned on the exhausting ...

Terminology in blood pH and gas analysis can be confusing, both because more than one name has been used for the same quantity, and because the same name has been used for more than one quantity. In addition, several calculated quantities are commonly used, but in some cases many different ...

Nuclear magnetic resonance (NMR) imaging shows promise in the measurement of human cerebral blood flow (CBF) in that nonradioactive indicators may be used. Our earlier investigations with trifluoromethane (FC-23) gas have shown that this compound can be used to safely and effectively measure CBF in anesthetized animal models. In this ...

An enclosed efferent, afferent reservoir breathing system (Maxima, Life Air Pty Ltd), being valveless, was compared to a simple afferent reservoir system (Humphrey ADE, A mode), having a valve, by assessing fresh gas flow (VF) requirements, with respect to ventilation (VE), that prevents rebreathing in volunteers, awake and breathing spontaneously. ...

We report a case where misleading readings form a pulse oximeter were compared with the results obtained from a continuous multiparameter blood gas sensor (Paratrend 7 - Biomedical Sensors UK). The continuous mode of recording was useful in determining the right clinical course for the patient and serves to show ...

In a double-blind, placebo-controlled study, pharmacokinetics and pharmacodynamics of 12 g piracetam in 2 different formulations were investigated utilizing blood gas analysis, EEG mapping and psychometry under a transient, reversible, hypoxic hypoxidosis. The latter was induced by a fixed gas combination of 9.8% oxygen (O2) and 90.2% nitrogen (N2, found ...

Pre-analytical variables, e.g., specimen collection, transport, and storage, can contribute significantly to inaccurate pH, blood gas, and electrolyte values. The International Federation of Clinical Chemistry (IFCC), through its Committee on pH, Blood Gases and Electrolytes, has developed specific recommendations to minimize the undesirable effects of pre-analytical variables. The Committee has ...

The medical use of ozone intraarterially, subcutaneously, intramuscularly and externally and in autohaemotransfusion or as a gas introduced into body cavities, as well as drops, compresses or liquids for rinsing etc. brings about very good therapeutic results. Ozone exerts a positive effect on oxygen and nutrient supply of cells, it ...

The gas composition of the middle ear differs from that of air, and resembles the gas composition of mixed venous blood. This observation suggests the existence of a bi-directional route for gas diffusion between the middle ear and blood. In an attempt to demonstrate this route in a direct way, ...

In order to compare the effects of intraperitoneal and extraperitoneal insufflation of CO2, we obtained blood gas measurements and chest radiographs in dogs during insufflation into three sites: the peritoneal cavity alone, the retroperitoneal space with communication into the peritoneal cavity, and the retroperitoneal space alone. The blood pH fell ...

Low-flow intratracheal gas insufflation is known to be an effective means of providing partial ventilatory support in respiratory failure. We studied the effects of catheter position on intraluminal CO2 concentration profiles and gas transport resistance during intra-airway insufflation at 0.15 l.kg-1.min-1 in six anesthetized paralyzed mechanically hypoventilated dogs. The two ...

OBJECTIVES: The central hypothesis of this study was that microbubble survival, and subsequent left ventricular and myocardial ultrasound contrast, could be improved by altering microbubble gas to consist of a higher molecular weight (less diffusible) and less soluble gas. BACKGROUND: Microbubble survival after intravenous injection is shortened because of rapid ...

STUDY OBJECTIVE: To determine whether the lower solubility of desflurane, over that of isoflurane, enflurane, and halothane, favors its use in low-flow anesthesia. DESIGN: Prospective clinical study. SETTING: Technical University of Munich. PATIENTS: 40 elderly (> or = 65 yrs), ASA physical status II and III surgical patients. INTERVENTIONS: All ...

A prototype for the control of blood gases during extracorporeal circulation (ECC) has been built. It is composed of a CDI300 continuous gas blood analyzer, a programmable gas blender and an IBM PC. The air blender is composed of three mass flow controllers (air, oxygen and total flow rate). The ...

OBJECTIVE: The objective of our study was to evaluate the precision and safety of administering nitric oxide (NO) during full and partial ventilatory support. METHODS: NO was administered either using a microprocessor-controlled servo ventilator, substituting an NO-N2 mixture for the ventilator's usual air supply or by adding an NO-N2 mixture ...

In this study, we compared three gas compositions to determine if the duration of apnoea for SpO2 to decrease is proportionate to the oxygen fraction of the gas prior to apnoea. Twenty-five patients ASA physical status 1-2 aged two months to 12 years were included in the study. Anaesthesia was ...

Continuous intra-arterial blood gas monitoring is a new technique, possibly offering therapeutic advantages through improved monitoring in patients prone to hypoxaemia, hypercapnia and/or respiratory acidosis. Therefore, we studied the clinical applicability, reliability, precision and side effect of long-term continuous intra-arterial blood gas monitoring in patients suffering from severe acute respiratory ...

In vitro blood gas analysers inherently limit the frequency of serial blood gas measurements because of blood loss and cost. In vivo blood gas monitors eliminate an inherent cost and blood loss associated with measurement. Optode microsensing is a technology that can be readily adapted to in vivo measurement of ...

In order to analyse the effects of various physiological parameters including blood gas data on the cerebral oxygenation, we developed a model to enable us to estimate PtO2 (tissue PO2) from these physiological parameters. This model was applied successfully to a set of blood gas data of a patient who ...

During recent years interest has focused on two completely fluorinated ethers, desflurane and sevoflurane, which promise a shorter induction of and emergence from anesthesia. Their physicochemical properties differ from isoflurane, enflurane and halothane, thus requiring new technical equipment and leading to a change in anesthesiological procedures. Low-flow anesthesia with desflurane ...

Effects of 'cardiogenic oscillations' on alveolar plateau gas concentration slope measurements, constant expiratory pulmonary capillary blood flow, and DLCO determination have not been previously described. We examined cardiogenic oscillations during constant expiratory maneuvers to assess factors influencing magnitude of oscillations as well as effect of oscillatory phase at the start ...

The vaporization rates of enflurane were measured in 412 anaesthetics using appropriate fresh gas flow rates in Bain (12 litre min-1), Magill (6 litre min-1) and circle systems (3 litre min-1, 1 litre min-1 and "closed"). In all patients reducing the fresh gas flow rate resulted in lower enflurane consumption. ...

The clinical effect of inhaled radio-labeled (Technetium-99m diethylenetriamine-pentaacetic acid) methacholine was studied in two separate experiments performed in eight symptom-free asthmatics with bronchial hyperresponsiveness. Aerosols were formed by two different nebulizers, producing either mainly small aerosol particles (2-microns mass median aerodynamic diameter [MMAD]) for peripheral, or mainly large aerosol particles ...

In vitro testing of a new prototype intravenous membrane oxygenator (IMO) is reported. The new IMO design consists of matted hollow fiber membranes arranged around a centrally positioned tripartite balloon. Short gas flow paths and consistent, reproducible fiber geometry after insertion of the device result in an augmented oxygen flux ...

The coaxial Mapleson D (Bain) circuit is close to an ideal anaesthetic breathing circuit but it requires a high fresh gas flow (VF). The CO2 absorber circuit can be used with a low VF but the patient end is clumsy and hyperventilation is common unless a small tidal volume (VT) ...

For at least 170 years, attempts have been made to alleviate inadequate gas exchange of patients with respiratory failure. Major milestones in the struggle to assist failing natural lungs to achieve adequate blood gas exchange include utilization of oxygen inhalation therapy, mechanical ventilatory assistance, and development of both extracorporeal and ...

OBJECTIVE: Our objective was to investigate the accuracy of a new intravascular blood gas sensor, the Paratrend 7 (P7) (Biomedical Sensors Ltd, Pfizer Hospital Products Group, High Wycombe, England) in a porcine model. METHODS: A total of 12 sensors were inserted into 10 animals under total intravenous anesthesia. Changes in ...

The dominant problem in the design of an intracorporeal oxygenator is achieving gas transfer rates sufficient for physiological needs in the space available with acceptably low flow resistance to blood. Design problems still to be solved, when configurations with sufficient gas transfer effectiveness are well identified, are biological tolerance (including ...

The most proximal site to sample end-tidal CO2 with reasonable accuracy in infants during pulmonary ventilation using a Mapleson D circuit remains controversial. The utilisation of high fresh gas flow near the site of gas sampling dilutes the expired gas and causes an underestimation of end-tidal CO2. In this study ...

A mathematical model of an intravascular hollow-fiber gas-exchange device, called IVOX, has been developed using a Krogh cylinder-like approach with a repeating unit structure comprised of a single fiber with gas flowing through its lumen surrounded by a coaxial cylinder of blood flowing in the opposite direction. Species mass balances ...

A case involving a fatal overdose of mexiletine is presented. Quantitation of the drug was accomplished by gas chromatography with a flame-ionization detector. The presence of mexiletine was confirmed by gas chromatography-mass spectrometry. Toxicological analysis revealed the following tissue distribution of mexiletine: heart blood, 44.8 micrograms/mL; femoral blood, 10.0 micrograms/mL; ...

A study was conducted to investigate whether aspiration of amniotic fluid is associated with a deleterious effect on absorption of colostral immunoglobulins or on blood gas and acid-base values of healthy newborn calves. Fourteen calves purchased from commercial sources were transported to a research facility immediately after birth and fed ...

BACKGROUND: We compared the performance of a new, continuous intraarterial blood gas (CIABG) monitor with arterial values obtained periodically and analyzed by conventional equipment. METHODS: A CIABG monitoring system consisting of a sterile, disposable, fiberoptic sensor and a microprocessor-controlled monitor with a self-contained calibration unit and detachable display panel was ...

Pre-analytical variables, e.g., specimen collection, transport, and storage, can contribute significantly to inaccurate pH, blood gas, and electrolyte values. The International Federation of Clinical Chemistry (IFCC), through its Committee on pH, Blood Gases and Electrolytes, has developed specific recommendations to minimize the undesirable effects of pre-analytical variables. The Committee has ...

This study was designed to evaluate the impact of routine end-tidal anesthetic gas monitoring on the intraoperative hemodynamic stability and early recovery profile in 253 consenting ASA physical status I-III patients undergoing elective otolaryngologic procedures with isoflurane or enflurane anesthesia. Patients were randomly assigned to one of six treatment groups: ...

The new Tec 6 desflurane vaporizer is an electrically heated, pressurized, electromechanically coupled dual-circuit blender. We hypothesized that carrier gas viscosity should affect the electromechanical coupling of the fresh gas and vapor circuits, and that desflurane output should vary with different carrier gases. In the first portion of the study, ...

We present an automatic closed circuit anaesthesia ventilator designed for routine clinical use. The ventilator combines the benefits of high flow systems and true closed circuits, without their disadvantages. The system can be used with any FiO2, with air or nitrous oxide as carrier gas. Servo controlled delivery of modern ...

We investigated the vaporization of liquid isoflurane when infused directly into a circuit. Pooling of isoflurane occurred within the circuit tubing at infusion rates used during clinical practice when constant gas flows were used. Despite pooling, the concentration of isoflurane was linearly related to infusion rate. Cyclical gas flow, such ...

BACKGROUND: Sevoflurane reacts with soda lime, generating degradation products. The concentrations of sevoflurane degradation products in a low-flow circuit have been reported for anesthesia times of less than 5 h. In this study, sevoflurane degradation products generated during low-flow anesthesia exceeding 10 h were examined. METHODS: Sixteen patients received sevoflurane ...

It has been demonstrated in an experimental study in swine using the scanning electron microscope that a rebreathing technique utilising minimal fresh gas flowrates significantly improves climatization of anaesthetic gases. Consequently, effects of various anaesthetic techniques on airway climate must be assessed, which covers the need for suitable measuring devices. ...

Miniaturized sensors, based upon the principles of optical fluorescence, can measure in vivo the pH, pCO2 value and pO2 value of blood. In this report we studied continuous intra-arterial blood gas monitoring in 27 patients undergoing cardiac surgery (no. 16 coronary artery by-pass grafting, no. 2 valvular surgery) and major ...

The search for alternatives to carbon dioxide (CO2) for insufflation during laparoscopy has included the consideration of helium. Helium is attractive because it is noncombustible and has no pharmacologic effects. Unfortunately, it is also relatively insoluble in blood, which potentially could exacerbate a venous gas embolism. We performed rapid intravenous ...

The benefit of a continuous intra-arterial blood gas monitor is apparent to any physician who has ever waited for the return of blood gas values at the bedside of a critically ill patient. The potential for rapid detection and prompt treatment of blood gas changes, coupled with immediate evaluation of ...