New technologies for the noninvasive assessment of oxygen and carbon dioxide are transforming clinical practice. Transcutaneous monitoring of PO2 (PtcO2) and PCO2 (PtCO2) provides an approximation of PaO2 and PaCO2 values in hemodynamically normal individuals, but both PtcO2 and PtcCO2 diverge from the corresponding arterial values when cardiac output is reduced, even in the absence of hypotens...

47cc-2-2-043 Introduction Tracheal gas insufflation (TGI) is an adjunctive ventilatory technique that delivers fresh gas into the trachea either continuosly or only during a specific segment of the respiratory cycle (phasic flow) [1-4]. Two mechanisms are responsible for improving the efficacy of conventional tidal breaths during TGI [5-7]. First, fresh gas introduced by the catheter during exp...

EDITOR: Standard non-invasive monitoring during anaesthesia usually includes pulse oximetry saturated pressure of oxygen (SPO2) and end-tidal carbon dioxide (end-tidal CO2). They frequently fail to monitor blood gas changes during cardiac surgery due to reduction in perfusion, ambient light, hypothermia and the use of vasoconstrictors [1]. It is also impossible to monitor SPO2 during cardiopulm...

Prone maximal restraint position (PMRP, also known as hogtie or hobble) is often used by law enforcement and prehospital personnel on violent combative individuals in the field setting. Weight force is often applied to the restrained individual's back and torso during the restraint process. We sought to determine the effect of 25 and 50 lbs weight force on respiratory function in human subject ...

QUESTION What is the effect of the Mapleson C circuit compared with the Laerdal circuit in removing secretions and improving ventilation and gas exchange during manual hyperinflation? DESIGN Prospective, randomised, cross-over trial. PARTICIPANTS Twenty patients from a tertiary-level intensive care unit who were being mechanically ventilated. INTERVENTION Manual hyperinflation in side-lyi...

BACKGROUND The administration of a high FIO2 to COPD patients breathing spontaneously may result in hypercapnia, due to reversal of preexisting regional hypoxic pulmonary vasoconstriction, resulting in a greater dead space. Arterial blood gas trends have not been reported in these patients. In a 31-bed medical ICU in a teaching hospital we prospectively investigated the response of 17 CO2-retai...

Measurements of lung mechanical behaviour as a function of respiratory frequency may be associated with significantly increased ventilation at high breathing rates. It follows that these measurements may be influenced by hypocapnia which has been shown to increase airflow resistance and to decrease dynamic compliance. To examine this possibility we continuously monitored the end-tidal CO2 tensi...

Salt marshes are among the most productive ecosystems on Earth, and play an important role in the global carbon cycle. Net carbon dioxide (CO2) ecosystem exchanges in coastal salt marshes remain poorly investigated. In Spartina alterniflora dominated North American Atlantic coast marshes, the lack of a clear understanding of how Spartina alterniflora responds to flooding limits our current abil...

1. The pattern of breathing in 12 patients with severe irreversible airflow obstruction has been studied during ventilatory stimulation by rebreathing CO2. Mean maximum tidal volume response was only 1.23 +/- 0.30 litres (mean +/- SD); this represented 65% of mean measured vital capacity and 82% of mean measured inspiratory capacity. During the course of rebreathing mean total breath duration w...

The purpose of this study was to evaluate the effects of flumazenil (1 mg i.v.) on the ventilatory response of premedicated patients receiving a continuous infusion of midazolam for sedation. After assessing baseline ventilatory function using a modified Read rebreathing method for determining hypercapnic ventilatory drive, 16 healthy outpatients were administered fentanyl, 50 micrograms i.v., ...