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Biomedical subjects

R Stienstra

Publications and source records attributed to R Stienstra.

At least 19 recordsLinked to original sources
PubMed1996

Mechanism of action of an epidural top-up in combined spinal epidural anesthesia.

The purpose of this study was to elucidate the mechanism of action by which an epidural top-up reinforces anesthesia in combined spinal epidural anesthesia. Thirty patients scheduled to undergo lower limb orthopedic surgery were randomly allocated to three groups of 10 patients each. In all patients, a 16-gauge Tuohy needle was introduced into the epidural space. Using the needle through needle technique, each patient received a subarachnoid injection of 10 mg plain bupivacaine 0.5% through a long 27-gauge Whitacre spinal needle introduced into the subarachnoid space through the Tuohy needle. After withdrawal of the spinal needle, an epidural catheter was introduced into the epidural space. After the maximum level of sensory block after the subarachnoid injection had been established, an epidural top-up with 10 mL bupivacaine 0.5% (Group 1) or 10 mL saline (Group 2) was administered; patients in Group 3 received no epidural top-up. The maximum level of sensory block was then assessed for an additional 30 min. After the epidural top-up the maximum level of sensory block increased significantly by 4.8 +/- 1.6 segments in Group 1 and 2.0 +/- 2.0 segments in Group 2. In Group 3 there was a nonsignificant increase of 0.3 +/- 0.5 segments. Intergroup comparisons showed that this increase in Group 1 was significant compared with those in Groups 2 and 3, and that the increase in Group 2 was significant compared with that in Group 3. We conclude that the mechanism of action by which an epidural top-up reinforces anesthesia in combined spinal epidural anesthesia can be explained partly by an epidural volume effect and partly by an effect of the local anesthetic itself.

Adolescent↗
PubMed1995

Ropivacaine 0.25% versus bupivacaine 0.25% for continuous epidural analgesia in labor: a double-blind comparison.

We compared the effects of continuous epidural infusion of ropivacaine 0.25% with bupivacaine 0.25% on pain relief and motor block during labor, and on the neonate. Seventy-six full-term parturients in active labor requiring epidural analgesia were randomly allocated to receive either bupivacaine 0.25% or ropivacaine 0.25%. Fifteen minutes after a loading dose of 10 mL of the study drug, an epidural infusion with the same drug was started at 6-12 mL/h to maintain an adequate block. Top-up doses of 6-10 mL were given as required. At full cervical dilation, the epidural infusion was discontinued. The onset of pain relief (verbal scale), contraction pain (visual analog scale), intensity of motor block (modified Bromage scale), and duration of motor block were not statistically different between the groups. Apgar scores at 1 and 5 min after delivery were comparable. There was a higher proportion of the neonates in the ropivacaine group (26/31 = 84%) who had a neurologic and adaptive capacity score (NACS) > or = 35 2 h after delivery than in the bupivacaine group (18/29 = 62%). We conclude that ropivacaine 0.25% and bupivacaine 0.25% are equally effective for epidural pain relief during labor. Ropivacaine may have an advantage over bupivacaine regarding neonatal neurobehavioral performance during the first few hours after delivery, although further studies will be required to substantiate this.

Adolescent↗
PubMed1989

Spinal anesthesia with plain bupivacaine 0.5%: regression of sensory and motor blockade with different temperatures of the anesthetic solution.

Onset (defined as the time between injection and achievement of the highest level of sensory blockade), duration, and regression of sensory and motor blockade after the intrathecal administration of 3 mL plain bupivacaine 0.5%, previously equilibrated to either 37 degrees C or 20 degrees C, were studied in two groups of 20 patients. In patients receiving the solution equilibrated to 37 degrees C, the maximum level of sensory blockade was significantly higher (T 4.6 vs T 7.5), variability was smaller (SEM 0.33 vs 0.58), and duration of the sensory level of blockade at or above T 6, T 8, and T 10 was significantly longer (56 min vs 20 min, 101 min vs 59 min, and 131 min vs 77 min, respectively). There were no significant differences with regard to onset of sensory and motor blockade or either the time needed both for the sensory level of blockade to regress two segments from its highest level and to the first lumbar segment, or the duration of complete motor blockade of the lower limbs. It is concluded that the intrathecal administration of a bupivacaine solution previously equilibrated to 37 degrees C as compared with a solution injected at room temperature results in a higher, more predictable maximum sensory level of blockade with longer duration at or above T 6, T 8, and T 10.

Aged↗
PubMed1989

Needle direction affects the sensory level of spinal anesthesia.

The effect of the direction of the spinal needle on the sensory level of anesthesia was investigated. Three ml plain bupivacaine 0.5%, previously equilibrated to 37 degrees C, were injected intrathecally in two groups of twenty patients, who were kept sitting for three minutes after injection. In patients in group 1 a paramedian approach was used with an angle between the spinal needle and the patient's back of 50 degrees or less. In patients in group 2 a median or paramedian approach was used, the resultant angle between the spinal needle and the patient's back being between 70 degrees and 100 degrees. The differences between segmental levels of sensory loss between groups 1 and 2 (T 3.4 and T 5.1, respectively) and of temperature loss (T 2.6 and T 4.2, respectively) 30 minutes after injection of bupivacaine were statistically significant. It is concluded that a steep paramedian approach of the subarachnoid space with an angle of less than 50 degrees results in a cephalad spread averaging about 1.6 segments greater than when the needle is in the perpendicular position.

Anesthesia, Spinal↗
PubMed1988

The temperature of bupivacaine 0.5% affects the sensory level of spinal anesthesia.

Three milliliters of plain bupivacaine 0.5% was injected intrathecally in two groups of 20 patients. Group 1 received a solution that had been equilibrated to 37 degrees C, group 2 received a solution that had been equilibrated to 4 degrees C. Patients were kept sitting for 3 minutes after injection. All observations were observer-blind. The differences between segmental levels of sensory loss between groups 1 and 2 (T4 and T9, respectively) and of temperature loss (T3 and T8, respectively) 10 and 20 minutes after injection of bupivacaine were statistically significant. It is concluded that the time needed for thermal equilibration in the cerebrospinal fluid and hence temperature of the injected solution plays an important role in the sensory spread of plain bupivacaine 0.5%.

Aged↗
PubMed1987

Plain or hyperbaric bupivacaine for spinal anesthesia.

Three ml of bupivacaine 0.5%, either plain or in 8% glucose, was injected intrathecally in three groups of twenty patients. Group 1 received bupivacaine 0.5% plain; group 2 received bupivacaine 0.5% in 8% glucose. Patients in groups 1 and 2 were kept sitting for 3 min after injection. Patients in group 3 received bupivacaine 0.5% in 8% glucose and were placed in the supine horizontal position immediately after injection. Observations of patients in group 3 were observer blind and in groups 1 and 2 double blind. The differences between segmental levels of sensory and temperature loss between groups 1 and 2 and between groups 2 and 3 were statistically not significant. Motor blockade of the lower extremities was more intense in the patients who were kept sitting for 3 min (groups 1 and 2). It is concluded that both solutions are equally suitable for spinal anesthesia, provided patients receiving the plain solution are kept sitting for at least 2 min. When using hyperbaric bupivacaine, posture seems to have no influence on cephalad spread.

Aged↗
PubMed1983

Methyl atropine bromide versus atropine sulphate. A clinical comparison.

In a double blind clinical investigation we compared methyl atropine bromide to atropine sulphate in equivalent doses for their effects on changes in the heart rate and dryness of the mouth. Drugs were administered five minutes before the induction of anesthesia. Methyl atropine bromide appeared to have a stronger positive chronotropic effect on the heart rate and a more pronounced mouth drying action. Less dysrhythmias were observed after the methyl congener. Both drugs failed to alter blood pressure significantly. We concluded that methyl atropine bromide is superior to atropine sulphate because it does not produce side effects which may cause the central anticholinergic syndrome. For clinical use, however, methyl atropine bromide should be administered only in half-equivalent dose of atropine sulphate to prevent excessive tachycardia and dryness of the mouth.

Adult↗
PubMedDate not supplied

The first years of a consultation bureau for homosexuality.

The COC's attempt to form a consultation bureau which would supply social aid to homosexuals is presented. The details and problems of forming such a group, including financial matters, type of aid to be supplied, and staffing, are discussed. In conclusion, the total reformation of the bureau in the 1980's is explained. The reformation reflects the change in social tolerance toward homosexuality in The Netherlands.

Counseling↗
PubMedDate not supplied

Speed of injection does not affect subarachnoid distribution of plain bupivacaine 0.5%.

Three milliliters of plain bupivacaine 0.5%, previously warmed to 37 degrees C, was injected into the subarachnoid space in two groups of 20 patients. In Group 1, speed of injection of the bupivacaine solution was as fast as possible (mean, 0.54 ml/second), whereas in Group 2 the bupivacaine solution was administered at a rate of 0.05 ml/second. Patients were kept sitting for 3 minutes after completion of the subarachnoid injection. All observations were made by an observer unaware of the speed of injection. There were no statistically significant differences in onset to maximal level of sensory block (17.2 minutes in Group 1 versus 19 minutes in Group 2) or complete motor block of the lower limbs (9 minutes in both groups). The difference in the maximal level of sensory block as determined by pinprick (T4.9 in Group 1 versus T3.4 in Group 2) was statistically significant; this difference may be explained by the fact that the plain solution of bupivacaine 0.5% at 37 degrees C is hypobaric and patients in Group 2 were in the sitting position for 1 minute longer when measured from the start of the subarachnoid injection. It is concluded that a tenfold difference in speed of injection does not significantly affect subarachnoid spread or onset of sensory and motor block with 0.5% bupivacaine.

Anesthesia, Spinal↗
PubMedDate not supplied

The influence of temperature and speed of injection on the distribution of a solution containing bupivacaine and methylene blue in a spinal canal model.

Three milliliters of a solution containing 4.81 mg bupivacaine base and 0.029 mg methylene blue per milliliter (BMB) was injected in the middle of a vertically mounted spinal canal model containing 0.9% NaCl at 37 degrees C. The BMB solution injected was either equilibrated to 37 degrees C (Exp. I) or to 22 degrees C (Exp. II). Each experiment was conducted eight times, four times with a high speed of injection (+/- 0.6 ml/sec) and four times with a slow speed of injection (0.05 ml/sec). The density of the BMB solution was determined at 37 degrees C and at 22 degrees C and found to be, respectively, slightly hypobaric and slightly hyperbaric relative to the 0.9% NaCl solution of 37 degrees C. Three minutes after completion of the injection, nine 1-ml samples were drawn simultaneously from the site of injection and from eight sampling sites situated equally above and below the site of injection at 5-cm intervals, which were subsequently analyzed for methylene blue concentrations. Injection of the BMB solution equilibrated to 37 degrees C resulted in a distribution directed mainly upward, whereas injection of the BMB solution equilibrated to 22 degrees C showed distribution in a mainly downward direction. Variation in methylene blue concentrations was large, and no definite differences based on different speeds of injection were observed. It is concluded that small differences in baricity result in largely different distribution patterns that could explain the variability in sensory levels of blockade when using an isobaric solution for spinal anesthesia.

Bupivacaine↗