Comparison of Thoracic Injury Risk in Frontal Car Crashes for Occupant Restrained without Belt Load Limiters and Those Restrained with 6 kN and 4 kN Belt Load Limiters.

In France, as in other countries, accident research studies show that a large proportion of restrained occupants who sustain severe or fatal injuries are involved in frontal impacts (65% and 50%, respectively). In severe frontal impacts with restrained occupants and where intrusion is not preponderant, the oldest occupants very often sustain severe thoracic injuries due to the conventional seat belt. As we have been observing over the last years, we will expect in the coming years developments which include more solidly-built cars, as offset crash test procedures are widely used to evaluate the passive safety of production vehicles. The reduction of intrusion for the most severe frontal impacts, through optimization of car deformation, usually translates into an increase in restraint forces and hence thoracic injury risk with a conventional retractor seat belt for a given impact severity. It is, therefore essential to limit the restraint forces exerted by the seat belt on the thorax in order to reduce the number of road casualties. In order to address thoracic injury risk in frontal impact, Renault cars have been equipped with the Programmed Restraint System (PRS) since 1995. The PRS is a restraint system that combines belt load limitation and pyrotechnic belt pretension. In an initial design of the Programmed Restraint System (PRS1), the belt load limiter was a steel component designed to shear at a given shoulder force, namely 6 kN. It was mounted between the retractor and the lower anchorage point of the belt. The design of the PRS was modified in 1998 (PRS2), but the principle of load limitation was maintained. The threshold was decreased to 4 kN and this lower belt belt-force limiter has been combined with a specially designed airbag. This paper reports on 347 real-world frontal accidents where the EES (Equivalent Energy Speed) ranged from 35 to 75 km/h. One hundred and ninety-eight (198) of these accidents involved cars equipped with the 6 kN load limiter, and 149 involved cars equipped with the 4 kN load limiter. Based on this accident data, the study compares the thoracic injury risk for two occupant populations: belted occupants involved in accidents in which the vehicle was not equipped with a load limiter (378 cases with pyrotechnic pretensioners), and belted occupants involved in accidents in which the vehicles were equipped with 4 or 6 kN load limiters and pyrotechnic pretensioners (347 cases). One observes that a 4 kN load limitation results in a very important reduction of thoracic injury risk for all AIS levels, compared to others samples. 50 to 60% reduction for AIS 2+ was observed, as well as 75 to 85% for AIS 3+. The complete absence of AIS 4+ with a 4 kN load limiter must be stressed, though it remains more than 8% for the other samples (no limiter and 6 kN limiter).

Ropivacaine, 0.1%, plus sufentanil, 0.5 microg/ml, versus bupivacaine, 0.1%, plus sufentanil, 0.5 microg/ml, using patient-controlled epidural analgesia for labor: a double-blind comparison.

BACKGROUND: This study compared the administration of 0.1% ropivacaine and 0.5 microg/ml sufentanil with that of 0.1% bupivacaine and 0.5 microg/ml sufentanil via patient-controlled epidural analgesia route during labor. METHODS: Two hundred healthy pregnant women at term with a single fetus with a vertex fetal presentation were randomized in a double-blind fashion to receive either 0.1% ropivacaine and 0.5 microg/ml sufentanil or 0.1% bupivacaine and 0.5 microg/ml sufentanil using a patient-controlled epidural analgesia pump (5-ml bolus dose, 10-min locked-out period, no basal infusion). Pain score on a visual analog scale, Bromage score (0-3), level of sensory block, patient-controlled epidural analgesia ratio, drug use, supplemental boluses, and side effects were recorded at 30 min and then hourly. Mode of delivery, duration of first and second stages of labor, umbilical cord pH, Apgar scores of the newborn, and a measure of maternal satisfaction were recorded after delivery. RESULTS: No differences were seen between the two groups for pain scores on a visual analog scale during labor, volume of anesthetic solution used, mode of delivery, or side effects. Motor block during the first stage of labor was significantly less in the ropivacaine group than in the bupivacaine group (no motor block in 97.8 of patients vs. 88.3%, respectively; P < 0.01). Duration of the second stage of labor was shorter in the ropivacaine group (1.3 +/- 1.0 vs. 1.5 +/- 1.2 h [mean +/- SD]; P < 0.05). Maternal satisfaction was greater in the bupivacaine group (91 +/- 13 mm for contraction, 89 +/- 19 mm for delivery on a visual scale: 0 = not satisfied at all, 100 = fully satisfied) than in the ropivacaine group (84 +/- 21 and 80 +/- 25 mm; P < 0.0001). Patients in the ropivacaine group requested more supplemental boluses to achieve analgesia during the second stage of labor than those in the bupivacaine group (29.7 vs. 19.8%, respectively, requested one or more supplemental boluses; P < 0.05). CONCLUSIONS: Delivered as patient-controlled epidural analgesia, 0.1% ropivacaine and 0.5 microg/ml sufentanil produce less motor block but are clinically less potent than 0.1% bupivacaine and 0.5 microg/ml sufentanil.

[Peridural anesthesia with a bupivacaine-fentanyl combination. Effects on uterine contractility]. / Anesthésie péridurale par association bupivicaïne-fentanyl. Effets sur la contractilité.

One hundred-and-four induced labours were monitored with extra-amniotic open-ended tocography. In every case, anaesthesia was epidural, using both Bupivacaine and Fentanyl. In most cases, uterine contractility was not changed by this type of anaesthesia. Four cases of hypertonia, nevertheless, were observed immediately after the epidural was injected with large dips in the recordings of the fetal cardiac rate. Hypertonia lasted for no longer than seven minutes and no consequences for children were observed at the time of birth.