Comparison of two semicontinuous cardiac output pulmonary artery catheters after valvular surgery

SummaryThe aim of this study was to investigate the pharmacokinetics of sevoflurane uptake into the brain and body by comparing sevoflurane concentrations in internal jugular-bulb blood (Jsev), arterial blood (Asev) and pulmonary arterial blood (PAsev) over a fixed inspired sevoflurane concentration. Ten patients (aged 51-73 years), undergoing coronary artery bypass grafting surgery were enrolled in this study. They were anaesthetised using a constant 3.5% inspired sevoflurane concentration (C I sev) during the first hour of anaesthesia. During constant volume-controlled ventilation, we measured C I sev and end-tidal sevoflurane (C E sev) using infrared analysis. The sevoflurane concentration in the blood was analysed using gas chromatography, and cardiac output was measured using an Opti-Q pulmonary artery catheter. We found that it took 40 min for the brain concentration to equilibrate with arterial blood (Asev). Both C I sev-C E sev and Asev-PAsev gradients persisted during the study period. There was no further uptake of sevoflurane into the brain after 40 min; however, there was near-constant uptake into the body. Sevoflurane is widely used in clinical anaesthesia because of its relative lack of airway irritation or myocardial suppression effects. It has rapid induction and emergence characteristics compared with other available inhalation anaesthetic agents [1][2][3]. Sevoflurane, has a low blood ⁄ gas solubility coefficient and has been thought to have rapid uptake pharmacokinetics in human volunteers [4,5]. The brain ⁄ blood partition coefficient of volatile anaesthetics is important in determining the rate of brain tissue wash-in and wash-out, and wash-in and wash-out characteristics are the main determinants of the rate of induction of and recovery from anaesthesia.The uptake pattern of sevoflurane remains poorly quantified and its uptake into the brain and body has not yet been fully elucidated. However, it has been shown that there is a well-defined relationship between volatile anaesthetic partial pressure in the brain and anaesthetic effects [6,7]. The aim of inhalation anaesthesia is to produce, safely and conveniently, a partial pressure adequate for anaesthesia. The aim of this study was to establish the time required for sevoflurane changes in arterial blood (Asev), right internal jugular-bulb blood (Jsev) and pulmonary arterial blood (PAsev) under constant inspired concentrations of sevoflurane during the first hour of anaesthesia. The primary purpose of this study was to explore the relationship among end-tidal sevoflurane concentrations (C E sev), Asev, PAsev and Jsev at a fixed inspired sevoflurane concentration during the first hour of sevoflurane anaesthesia. Second, we compared the different uptake patterns of sevoflurane in the Anaesthesia, 2003, 58, pages 951-956

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Pharmacokinetics of sevoflurane uptake into the brain and body

Lu¹,

Tsai²,

et al. 2003

“…A nasopharyngeal thermistor was used to measure body temperature, which was allowed to decrease passively to 34–36 °C during the study period. Cardiac output was continuously measured using the Opti‐Q catheter (Abbott Critical Care System, Mountain View, CA) [11] with the Q‐Vue continuous cardiac output computer (Abbott Critical Care System).…”

Section: Methodsmentioning

confidence: 99%

Pharmacokinetics of desflurane uptake into the brain and body

Lu¹,

Tsai

et al. 2004

SummaryThe aim of this study was to investigate the pharmacokinetics of desflurane uptake into the brain and body by comparing desflurane concentrations in internal jugular-bulb blood (Jdes), arterial blood (Ades) and pulmonary arterial blood (PAdes) at a fixed inspired desflurane concentration. Thirteen patients (aged 42-72 years) undergoing coronary artery bypass grafting surgery were enrolled in this study. They were anaesthetised using a constant 5% inspired desflurane concentration (C I des) during the first hour of anaesthesia. Under constant volume-controlled ventilation, C I des and end-tidal desflurane (C E des) were measured with an infrared analyser. The desflurane concentration in the blood was analysed using gas chromatography, and cardiac output was measured using an Opti-Q pulmonary artery catheter. It took 24 min for the Jdes to equilibrate with Ades. Both C I des-C E des and Ades-PAdes gradients persisted during the study period. There was no further uptake of desflurane into the brain after 24 min but there was near-constant uptake into the body.

“…At present, several techniques based on warm thermodilution [2] are commercially available for continuous cardiac output monitoring. While their accuracy appears to be acceptable [3–10], the main disadvantage of the current systems is that their response is delayed by several minutes [3,6,8,11,12]. In addition, their accuracy is impaired in patients with cardiac outputs >10 l.min −1 [4,8,13].…”

mentioning

confidence: 99%

Evaluation of a new continuous cardiac output monitor in off‐pump coronary artery surgery

Leather¹,

Vuylsteke

Bert³

et al. 2004

SummaryWe evaluated a new, ultra-fast response continuous cardiac output monitor in 34 adult patients undergoing off-pump coronary artery bypass graft surgery. Cardiac output was measured with the TruCCOMS Ò continuous cardiac output monitor (Aortech International plc, Lanarkshire, UK), using triplicate cold bolus thermodilution as the criterion standard, at fixed time points during surgery and during dobutamine infusion. The two techniques were compared using linear regression and Bland-Altman analysis. Overall, the study device displayed a bias of 0.4 l.min )1 with limits of agreement of +2.5 l.min )1 and )1.7 l.min )1 . The study device failed to detect the change in cardiac output caused by dobutamine accurately (y = 0.18x + 0.45; r 2 = 0.13), with an error linearly related to the magnitude of the change measured. We conclude that the device's failure to detect changes in cardiac output could be a major limitation in its clinical use in its current form.