The effect of remifentanil on propofol requirements to achieve loss of response to command vs. loss of response to pain

Scott, Heidi; Choi, S. W.; Wong, Gtc; Irwin, Michael G.

doi:10.1111/anae.13781

Cited by 40 publications

(28 citation statements)

References 33 publications

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“…In addition, we found stable arterial‐venous differences throughout the study period and stable measured propofol Cp and BIS at minute 7 and minute 14 of the long step. Furthermore, propofol Cp estimated at LOR were in accordance with previously reported values . While, as stated by Cortínez , blood measurements provide no guide to equilibration between the blood and effect‐site concentrations, the relatively stable BIS values observed at minute 7 and 14 of the long step (61.2 (49–77) vs. 58.4 (45–74)) do suggest that propofol concentrations were relatively stable at the effect‐site (Fig.…”

Section: Discussionsupporting

confidence: 89%

Evidence of hysteresis in propofol pharmacodynamics

et al. 2017

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SummaryIt is commonly assumed that loss of responsiveness and recovery of responsiveness occur at similar concentrations of propofol. However, the 'conscious' and 'anaesthetised' conditions produced by general anaesthetics may behave as two bistable states. We hypothesised that loss of responsiveness and recovery of responsiveness occur at different propofol concentrations. Propofol was administered to 19 healthy volunteers by effect-site target-controlled infusion using increasing and decreasing stable concentration steps of 7 min. Propofol serum concentrations were measured from venous blood samples at the end of each 7-min step. A long step of 14 min was performed at loss of responsiveness. At this step, propofol concentrations were measured at 7 and 14 min. Propofol concentrations measured at loss of responsiveness and recovery of responsiveness were 2.6 (1.2-4.7) lg.ml À1 and 1.6 (0.6-3.3) lg.ml À1, respectively (p < 0.001). Propofol plasma concentration and the corresponding bispectral index values measured at minute 7 and minute 14 of the long step performed at loss of responsiveness were 2.6 (1.2-4.7) vs. 2.6 (1.3-4.3) at recovery of responsiveness, (p = 0.96) and 61.2 (49.0-77.0) vs. 58.4 (45.0-74.0), (p = 0.058), respectively. Loss of responsiveness and recovery of responsiveness appear to occur at different propofol concentrations. However, it is possible that, if equilibration was not achieved between plasma and effect-sites at the end of each 7-min step, the higher concentrations found at loss of responsiveness compared with those observed during recovery of responsiveness could be explained by a possible bias in estimations of the effect-site concentrations of propofol by the Schnider model, rather than neural inertia.

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Section: Discussionsupporting

confidence: 89%

Evidence of hysteresis in propofol pharmacodynamics

et al. 2017

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“…Synergy of effect occurs between propofol and opioids. Opioids reduce the propofol dose required to produce loss of consciousness and, in particular, to obtund movement and haemodynamic responses to noxious stimuli . A remifentanil infusion is often used in conjunction with propofol infusion.…”

Section: Choosing An Appropriate Target Drug Concentration For a Patientmentioning

confidence: 99%

Guidelines for the safe practice of total intravenous anaesthesia (TIVA)

et al. 2018

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Summary Guidelines are presented for safe practice in the use of intravenous drug infusions for general anaesthesia. When maintenance of general anaesthesia is by intravenous infusion, this is referred to as total intravenous anaesthesia. Although total intravenous anaesthesia has advantages for some patients, the commonest technique used for maintenance of anaesthesia in the UK and Ireland remains the administration of an inhaled volatile anaesthetic. However, the use of an inhalational technique is sometimes not possible, and in some situations, inhalational anaesthesia is contraindicated. Therefore, all anaesthetists should be able to deliver total intravenous anaesthesia competently and safely. For the purposes of simplicity, these guidelines will use the term total intravenous anaesthesia but also encompass techniques involving a combination of intravenous infusion and inhalational anaesthesia. This document is intended as a guideline for safe practice when total intravenous anaesthesia is being used, and not as a review of the pros and cons of total intravenous anaesthesia vs. inhalational anaesthesia in situations where both techniques are possible.

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“…We also had no study subjects developing hypotension (systolic blood pressure < 90 mmHg) . Remifentanil does not cause much sedation . All our patients were lightly sedated at most, and remained responsive throughout the study.…”

Section: Discussionmentioning

confidence: 97%

A case series of vital signs-controlled, patient-assisted intravenous analgesia (VPIA) using remifentanil for labour and delivery

et al. 2017

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Intravenous remifentanil patient-controlled analgesia can be used during labour as an alternative to epidural analgesia. Adverse effects of opioids, including hypoxia and bradycardia, may lead to maternal morbidity and mortality. We devised an interactive feedback system based on a clinical proportional algorithm, to continuously monitor for adverse effects to enhance safety and better titrate analgesia. This vital signs-controlled, patient-assisted intravenous analgesia with remifentanil used a prototype delivery system linked to a pulse oximeter that evaluated maternal oxygen saturation and heart rate continuously. With this system, we detected oxygen saturation < 95% for more than 60 s in 15 of 29 subjects (52%); and heart rate < 60 min for more than 60 s in 7 of 29 subjects (24%) during use. The system automatically responded appropriately by reducing the dosages and temporarily halting remifentanil administration, thus averting further hypoxia and bradycardia.

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The effect of remifentanil on propofol requirements to achieve loss of response to command vs. loss of response to pain

Cited by 40 publications

References 33 publications

Evidence of hysteresis in propofol pharmacodynamics

Evidence of hysteresis in propofol pharmacodynamics

Guidelines for the safe practice of total intravenous anaesthesia (TIVA)

A case series of vital signs-controlled, patient-assisted intravenous analgesia (VPIA) using remifentanil for labour and delivery

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