Ropivacaine 0.1% with fentanyl 2 microg mL(-1) by epidural infusion for labour analgesia.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of 0.1% ropivacaine with fentanyl 2 microg mL(-1) via epidural for analgesia in labour. METHODS: In a randomized study, 80 nulliparous parturients in labour had epidural analgesia initiated with 0.2% ropivacaine and fentanyl and were then randomized to receive either 0.1% ropivacaine with fentanyl 2 microg mL(-1) at 10mL h(-1) (Group R1, n = 38) or 0.2% ropivacaine with fentanyl 2 microg mL(-1) at 8 ml h(-1) (Group R2, n = 39) as epidural infusions. Supplementary analgesia was provided on request with ropivacaine 0.2% 5 mL as an epidural bolus. RESULTS: There were no significant differences between the visual analogue pain scores either with respect to motor block or sensory block. The amount of local anaesthetic used was lower in the 0.1% ropivacaine group than in the 0.2% ropivacaine group (P = 0.001). Side-effects, patient satisfaction, labour outcome and neonatal outcomes were similar in both groups. CONCLUSIONS: An epidural infusion of 0.1% ropivacaine with fentanyl 2 microg mL(-1) at 10 mL h(-1) provided adequate analgesia in the first stage of labour. The level of analgesia was similar to that obtained using 0.2% ropivacaine with fentanyl 2 microg mL(-1) and with no differences with regard to motor or sensory block.

[Cardiocirculatory effects of intravenous anesthetic induction in an experimental model of acute hypovolemia]. / Efectos cardiocirculatorios de la inducción anestésica intravenosa en un modelo experimental de hipovolemia aguda.

OBJECTIVE: To evaluate the cardiovascular effects of ketamine, midazolam, thiopentone and propofol in acutely hypovolemic pigs and to determine whether the association of ketamine and midazolam offers any advantage. PATIENTS AND METHODS: Twenty-two Landrace-Large-White pigs. After monitoring was begun, acute hypovolemia was induced by means of rapid exsanguination of 30% of calculated volume. Hemodynamic variables were measured: a) at baseline; b) after exsanguination; c) 2 min after anesthetic induction; d) 10 min after anesthetic induction, and e) after reinfusion of the exsanguinated volume. RESULTS: All pressures, cardiac output, cardiac index, and mixed venous oxygen saturation fell significantly with the induction of hypovolemia. Heart rate, systemic vascular resistances and arteriovenous oxygen differential increased. Ten min after anesthetic induction, heart rate in the midazolam group was significantly lower than in the ketamine-midazolam group. Arterial pressures decreased significantly after anesthetic induction with all drugs. The decrease in systolic arterial pressure was smaller in thiopenthal-anesthetized pigs than in pigs receiving either midazolam or propofol at the 10 min recording. The decrease in mean arterial and diastolic pressure after 10 min was smaller with thiopental than with any other drug. The decrease in mean arterial pressure was less in the thiopental and ketamine-midazolam groups than in the others after reinfusion. Diastolic arterial pressure at 10 min and after reinfusion had decreased less in the thiopental and ketamine-midazolam groups than in the propofol group. After anesthetic induction, the post-hypovolemic figures for cardiac output and cardiac index held steady or changes were slightly accentuated, with no statistically significant differences among the groups. CONCLUSIONS: The intravenous anesthetics evaluated were detrimental to cardiovascular function in acute hypovolemic pigs. Low-dose thiopental and ketamine plus midazolam may be the anesthetics of choice in this setting. Propofol caused the greatest degree of hemodynamic instability.