Improved haemodynamic stability and cerebral tissue oxygenation after induction of anaesthesia with sufentanil compared to remifentanil : a randomised controlled trial

Background: Balanced anaesthesia with propofol and remifentanil, compared to sufentanil, often decreases mean arterial pressure (MAP), heart rate (HR) and cardiac index (CI), raising concerns on tissue-oxygenation. This distinct haemodynamic suppression might be attenuated by atropine. This double blinded RCT, investigates if induction with propofol-sufentanil results in higher CI and tissue-oxygenation than with propofol-remifentanil and if atropine has more pronounced beneficial effects on CI and tissue-oxygenation in a remifentanil-based anaesthesia. Methods: In seventy patients scheduled for coronary bypass grafting (CABG), anaesthesia was induced and maintained with propofol target controlled infusion (TCI) with a target effect-site concentration (Cet) of 2.0 mu g ml(- 1)and either sufentanil (TCI Cet 0.48 ng ml(- 1)) or remifentanil (TCI Cet 8 ng ml(- 1)). If HR dropped below 60 bpm, methylatropine (1 mg) was administered intravenously. Relative changes (increment ) in MAP, HR, stroke volume (SV), CI and cerebral (SctO(2)) and peripheral (SptO(2)) tissue-oxygenation during induction of anaesthesia and after atropine administration were analysed. Results: The sufentanil group compared to the remifentanil group showed significantly less decrease in MAP (increment = - 23 +/- 13 vs. -36 +/- 13 mmHg), HR (increment = - 5 +/- 7 vs. -10 +/- 10 bpm), SV (increment = - 23 +/- 18 vs. -35 +/- 19 ml) and CI (increment = - 0.8 (- 1.5 to - 0.5) vs. -1.5 (- 2.0 to - 1.1) l min(- 1) m(- 2)), while SctO(2) (increment = 9 +/- 5 vs. 6 +/- 4%) showed more increase with no difference in increment SptO(2) (increment = 8 +/- 7 vs. 8 +/- 8%). Atropine caused higher increment HR (13 (9 to 19) vs. 10 +/- 6 bpm) and increment CI (0.4 +/- 0.4 vs. 0.2 +/- 0.3 l min(- 1) m(- 2)) in sufentanil vs. remifentanil-based anaesthesia, with no difference in increment MAP, increment SV and increment SctO(2) and increment SptO(2). Conclusion: Induction of anaesthesia with propofol and sufentanil results in improved haemodynamic stability and higher SctO(2) compared to propofol and remifentanil in patients having CABG. Administration of atropine might be useful to counteract or prevent the haemodynamic suppression associated with these opioids

Phenylephrine increases cardiac output by raising cardiac preload in patients with anesthesia induced hypotension

Induction of general anesthesia frequently induces arterial hypotension, which is often treated with a vasopressor, such as phenylephrine. As a pure -agonist, phenylephrine is conventionally considered to solely induce arterial vasoconstriction and thus increase cardiac afterload but not cardiac preload. In specific circumstances, however, phenylephrine may also contribute to an increase in venous return and thus cardiac output (CO). The aim of this study is to describe the initial time course of the effects of phenylephrine on various hemodynamic variables and to evaluate the ability of advanced hemodynamic monitoring to quantify these changes through different hemodynamic variables. In 24 patients, after induction of anesthesia, during the period before surgical stimulus, phenylephrine 2 mu gkg(-1) was administered when the MAP dropped below 80% of the awake state baseline value for >3min. The mean arterial blood pressure (MAP), heart rate (HR), end-tidal CO2 (EtCO2), central venous pressure (CVP), stroke volume (SV), CO, pulse pressure variation (PPV), stroke volume variation (SVV) and systemic vascular resistance (SVR) were recorded continuously. The values at the moment before administration of phenylephrine and 5(T-5) and 10(T-10)min thereafter were compared. After phenylephrine, the mean(SD) MAP, SV, CO, CVP and EtCO2 increased by 34(13)mmHg, 11(9)mL, 1.02(0.74)Lmin(-1), 3(2.6)mmHg and 4.0(1.6)mmHg at T-5 respectively, while both dynamic preload variables decreased: PPV dropped from 20% at baseline to 9% at T-5 and to 13% at T-10 and SVV from 19 to 11 and 14%, respectively. Initially, the increase in MAP was perfectly aligned with the increase in SVR, until 150s after the initial increase in MAP, when both curves started to dissociate. The dissociation of the evolution of MAP and SVR, together with the changes in PPV, CVP, EtCO2 and CO indicate that in patients with anesthesia-induced hypotension, phenylephrine increases the CO by virtue of an increase in cardiac preload

Journal of Clinical Monitoring and Computing 2017/2018 end of year summary:monitoringand provocationof the microcirculation and tissue oxygenation

The microcirculation is the ultimate goal of hemodynamic optimization in the perioperative and critical care setting. In this fourth end-of-year summary of the Journal of Clinical Monitoring and Computing on this topic, we take a closer look at papers published in the last 2years that focus on this important aspect. The majority of these papers investigated the use of either cerebral or peripheral tissue oxygen saturation, derived non-invasively using near infrared spectroscopy (NIRS). In some of these studies, the microcirculation was provocated by inducing short-term tissue hypoxia, allowing the assessment of functional microvascular reserve. Additionally, studies on technical differences between NIRS monitors are summarized, as well as studies investigating the feasibility of NIRS monitoring, mainly in the pediatric patient population. Last but not least, novel monitoring tools allow assessing oxygenation at a (sub)cellular level, and those papers incorporating these techniques are also reviewed here

Comparison of continuous non-invasive finger arterial pressure monitoring with conventional intermittent automated arm arterial pressure measurement in patients under general anaesthesia

Background: For a majority of patients undergoing anaesthesia for general surgery, mean arterial pressure (MAP) is only measured intermittently by arm cuff oscillometry (MAP(iNIAP)). In contrast, the Nexfin (R) device provides continuous non-invasive measurement of MAP (MAP(cNIAP)) using a finger cuff. We explored the agreement of MAP(cNIAP) and MAP(iNIAP) with the gold standard: continuous invasive MAP measurement by placement of a radial artery catheter (MAP(invasive)). Methods: In a total of 120 patients undergoing elective general surgery and clinically requiring MAP(invasive) measurement, MAP(iNIAP) and MAP(cNIAP) were measured in a 30 min time period at an arbitrary moment during surgery with stable haemodynamics. MAP(iNIAP) was measured every 5 min. Results: Data from 112 patients were analysed. Compared with MAP(invasive), modified Bland-Altman analysis revealed a bias (SD) of 2 (9) mm Hg for MAP(cNIAP) and -2 (12) mm Hg for MAP(iNIAP). Percentage errors for MAP(cNIAP) and MAP(iNIAP) were 22% and 32%, respectively. Conclusions: In a haemodynamically stable phase in patients undergoing general anaesthesia, the agreement with invasive MAP of continuous non-invasive measurement using a finger cuff was not inferior to the agreement of intermittent arm cuff oscillometry. Continuous measurements using a finger cuff can interchangeably be used as an alternative for intermittent arm cuff oscillometry in haemodynamically stable patients, with the advantage of beat-to-beat haemodynamic monitoring