瑞芬分娩鎮(zhèn)痛的運用和問題課件

1、Remifentanil PCA labor analgesia: applications and concerns瑞芬分娩鎮(zhèn)痛的運用和問題Remifentanil Specifics:Remifentanil is an opioid with an ESTER bond (other common esters in anesthesia)succinylcholineesmololRemifentanil is metabolized by nonspecific esterases in blood and tissue (mostly gut)The placenta is ful

2、l of esterasesNearly fully developed at time of birthRemifentanil:Pharmacokinetics and Pharmacodynamicsthat make it useful in labor and deliveryExtremely rapid onsetExtremely rapid offsetLimited variability between individual patientsRapid onset of bolus doseRemifentanil bolus injection vs. other op

3、ioidsMinutes since bolus injection0246810Percent of peak effect site opioid concentration020406080100fentanylsufentanilalfentanilremifentanilMinto et al, Anesthesiology 86:10-23, 1997Remifentanil bolus injection vs. other opioidsMinutes since bolus injection0246810Percent of peak effect site opioid

4、concentration020406080100remifentanilMinto et al, Anesthesiology 86:10-23, 1997-Rapid onset of bolus dose allows for anticipation of contraction-Often peak analgesic effect lags behind peak of contractionRapid offsetRemifentanil MetabolismExtremely rapid offset (half life 3-4 minutes)Not influenced

5、by:Hepatic diseaseRenal diseasePseudocholinesterase deficiencyAdministration of neostigmineVery young age (fetus)The remifentanil “Unit Disposition Function”Expected plasma concentration following bolus of 1 unitAge range: 20-85 yrsVery rapid decreaseLess variability than with other anesthetic drugs

6、 and opioidsMinto et al, Anesthesiology 86:10-23, 1997Rapid decrease after infusion0.1110100060120180240300360420480Minutes Concentration (ng/ml)Glass et al, Anesth Analg 77:1031-1040, 1993Remifentanil concentration after bolus vs. other opioidsMinutes since bolus injection0120240360480600Percent of

7、 peak plasmaopioid concentration0.1110100fentanylsufentanilalfentanilremifentanilMinto et al, Anesthesiology 86:10-23, 1997Rapid recovery from ventilatory depressionGlass et al, Anesth Analg 77:1031-1040, 1993Remifentanil vs. other opioidsNo accumulation regardless of length of infusion: critical fo

8、r use in laborRecovery from remifentanil is unlike that seen with any other opioidThe time to a given decrease in effect site concentration is constant over time of infusionno accumulation0204060Minutes required for a given percent decrease in effect site concentration0306090120Minutes since beginni

9、ng of infusion012024036048060006012018024030020% decrease50% decrease80% decreasefentanylfentanylfentanylalfentanilalfentanilalfentanilsufentanilsufentanilsufentanilremifentanilremifentanilremifentanilMinto et al, Anesthesiology 86:10-23, 1997Setting up drug infusionsCheck out your pump as thoroughl

10、y as you check out your anesthesia machine.Is your drug dilution correct?Is the syringe adequately held?Is the syringe plunger properly held in the clamp? Are your infusion units correct?Is the weight correct (for calculator pumps)?Has the dead space been taken out of the line?Have the batteries bee

11、n checked?Many complications are due to concentration and pump errors.Setting up drug infusions Infuse as close to the IV catheter site as possible.Typical IV tubing contains 3-5 mls of dead space between injection ports and catheter.Bolus Dose EquivalentsRemifentanil 70 mg (1 mg/kg) Fentanyl 225 mg

12、 (3.2 mg/kg)Alfentanil 1000 mg (15 mg/kg)Sufentanil 25 mg (0.35 mg/kg)Remifentanil 35 mg (0.5 mg/kg) Fentanyl 100 mg (1.5 mg/kg)Alfentanil 500 mg (7 mg/kg)Sufentanil 12 mg (0.2 mg/kg)Bolus vs InfusionConcentrations rapidly rise during infusions.With infusions, expect apnea and rigidity within 2-3 mi

13、nutes.Especially at a rate of 1.0 mg/kg/minLower bolus doses and/ or infusion rates are required for labor analgesia.05101520250246810MinutesRemifentanil concentration (ng/ml)1.0 mg/kg/min1 mg/kg bolusApneaVentilatory DepressionRigidity0.5 mg/kg/minInfusion rates0.2 mg/kg/min Apnea likely0.1 mg/kg/m

14、in Respiratory depression0.05 mg/kg/min Little likelihood of respiratory depression0.025 mg/kg/minFew problems expectedModestly analgesic02468100102030405060MinutesRemifentanil concentration (ng/ml)0.1 mg/kg/min0.025 mg/kg/minRespiratory depressionApneaRigidity0.05 mg/kg/min0.2 mg/kg/minAnalgesiaUse

15、 of Remifentanil in ObstetricsCan be used as patient controlled analgesia Can be used as an infusionLimited reports of success with both patient controlled analgesia and a background infusionMultiple case reports of respiratory depressionHowever one large retrospective trial from Shanghai with good

16、results will be discussed in detail.Analgesia in ObstetricsRegional is still king!Not everybody is eligibleAt Columbia University in New York, approximately 90% of women who deliver vaginally have epidural analgesia. At Stanford University, 80% have epidural analgesiaNearly 100% want analgesia.Contr

17、aindications:Anticoagulation SepsisNeurological DiseasesNeedle phobia- not everybody wants a needle stuck in her backComparison of Remifentanil to other opioids and nitrous oxideComparison of Remifentanil and Nitrous Oxide in Labor Analgesia P. Volmanen, E. Akural, T. Raudaskoski, P. Ohtonen and S.

18、Alahuhta. Acta Anaesthesiol Scand 2005; 49:453-458.Protocol: Bolus 0.4 mg/kg- lockout 1 minute- or 50% nitrousRemifentanil group- VAS scores were reduced from 7 to 4.5.Nitrous group- VAS scores not significantly differentRemifentanil group was more sedatedPatient controlled analgesia for labour: a c

19、omparison of remifentanil with pethidine.Blair JM, Dobson GT, Hill DA, McCracken GR, Fee JP. Anaesthesia. 2005 Jan;60(1):22-7. Protocol: Bolus Remifentanil 40 mg- lockout 2 minute- or Pethidine (meperidine) 15mg- lockout 10 minutesVAS scores were not different (6.4 vs. 6.9)Women strongly preferred r

20、emifentanilRemifentanil group was more sedatedRecent large retrospective trial in Shanghai compared to epiduralLin R, Tao Y, Yu Y, Xu Z, Su J, and Liu Z. Intravenous Remifentanil versus Epidural Ropivacaine with Sufentanil for Labour Analgesia: A Retrospective Study. PLoS One. 2014; 9(11)200 epidura

21、ls: 170 remifentanilCombined infusion 0.04-0.05 mcg.kg/min with option for PCA bolus of 0.4 mcg/kg q 5 minutes.All parturients had supplemental oxygen and 1:1 supervisonPain Scores: Epidural had better, more consistent pain relief with higher satisfactionOxygen saturation- frequent desaturation with onset, prior to shift of CO2 response curve : Critical time for