Search PubMed⌕ Search

Biomedical subjects

S Alahuhta

Publications and source records attributed to S Alahuhta.

At least 37 records · Page 2Linked to original sources
PubMed2000

The hemodynamic effects of adenosine infusion after experimental right heart infarct in young swine.

The use of a vasodilator selective to the pulmonary circulation may be beneficial in cases with right-ventricle failure, as it will decrease right-heart afterload without concurrent systemic hypotension. Adenosine has recently been advocated as such a drug, although its clinical efficacy in this respect is still in question. We therefore devised an experimental protocol of right-heart infarct to test the efficacy of adenosine in alleviating symptoms of right-heart failure. Right-heart infarct was induced experimentally in 17 young pigs. After hemodynamics had stabilized, preload was optimized with a dextrose-based colloid solution. A continuous infusion of adenosine was then begun at doses of 25, 50, 75, and 100 microg/kg/min in a study group of 10 animals, while the remaining seven were monitored as controls. Hemodynamic parameters were followed throughout the study, with particular attention paid to pulmonary and systemic vascular resistance indices (PVRI and SVRI), right ventricle ejection fraction (REF), cardiac index (CI), and heart rate (HR). Cardiac index (CI) showed a tendency to increase during the adenosine infusion, as did REF and stroke index (SI), whereas PVRI and mean pulmonary pressure (MPAP) were decreased. There was a marked decrease in SVRI as a result of the adenosine, as there was in mean arterial pressure at the higher infusion rates. HR remained unchanged by the infusion. Discontinuation of the drug resulted in a rapid increase in MAP, SVRI, MPAP, HR, left ventricle stroke work index (LVSWI), and PVRI and in a modest decrease in CI. The continuous infusion of adenosine appears to cause an effective arterial vasodilation, with a consequent unloading of right-heart afterload. Its use may be beneficial in the treatment of increased pulmonary vascular resistance after right-heart failure.

Adenosine↗
PubMed1999

Tibial nerve somatosensory evoked potentials during EEG suppression in sevoflurane anaesthesia.

OBJECTIVES AND METHODS: Cortical tibial nerve somatosensory evoked potentials (TSEPs) were recorded from 10 subjects in sevoflurane anaesthesia in order to study TSEP during EEG suppression. RESULTS: With a stimulation frequency less than one per second the major component was a positive wave which had maximal amplitude parietally ipsilaterally to stimulus and mean latency of 46.1 ms. It probably corresponds to the P40 wave. It was preceded by a widespread smaller positive wave, which corresponds to the subcortical P30 wave. In two patients a high amplitude negative wave, a couple of milliseconds before the positive wave, and maximal parietally contralateral to stimulus, was seen. All later waves were absent. CONCLUSION: The results are in agreement with our previous results from median nerve SEPs showing that the first cortical response from primary somatosensory cortex is enhanced, and later waves are suppressed. Hence, recording TSEPs during EEG suppression provides a way to record the activity of the primary somatosensory cortex accurately and rapidly due to the very good signal to noise ratio, so that even single responses to stimuli can be seen without averaging. Our results suggest that new cortical generators, which are not recordable awake, may be discovered in some patients.

Adult↗
PubMed1999

Clinical efficacy and pharmacokinetics of 1% ropivacaine and 0.75% bupivacaine in peribulbar anaesthesia for cataract surgery.

Peribulbar anaesthesia with 1% ropivacaine and 0.75% bupivacaine, both with hyaluronidase, was assessed in a prospective, randomised, double-blind study of 100 patients undergoing cataract surgery. Pharmacokinetic data were obtained from 22 subjects. Akinesia of the globe developed slightly more rapidly in the ropivacaine group, but this difference was only statistically significant at 2 min after injection of the local anaesthetic. Lid akinesia was significantly more complete in the ropivacaine group. There were no differences between the groups with respect to peri-operative analgesia or duration of akinesia. The dose-adjusted maximum concentration of ropivacaine was approximately twice that of bupivacaine with significantly higher values of the area under the concentration-time curves. No drug-related adverse effects were observed. We conclude that there are no clinically significant differences in the quality of the sensory and motor block between 1% ropivacaine and 0.75% bupivacaine when used for peribulbar anaesthesia.

Aged↗
PubMed1998

Maternal, fetal and placental distribution of lidocaine-epinephrine and bupivacaine after epidural administration for cesarean section.

Bupivacaine and lidocaine are both lipophilic drugs, bupivacaine being more lipophilic and protein-bound. Our earlier studies, using human placenta perfused in vitro, showed that increased placental binding of bupivacaine restricts fetal transfer compared to the higher fetal transfer of lidocaine. However, placental tissue concentrations of local anesthetics have not been determined in the clinical context. Term parturients were randomized to receive either 2% lidocaine-epinephrine (n = 10) or 0.5% bupivacaine (n = 10) through a lumbar epidural catheter for elective cesarean section. Total drug concentrations of lidocaine and bupivacaine in maternal and umbilical plasma and placental tissue were determined. There was a higher incidence of maternal hypotension in the lidocaine-epinephrine group than in the bupivacaine group ( vs , P < 0.05). At delivery, fetal/maternal ratios for total concentrations of lidocaine and bupivacaine were similar (0.49 vs 0.42). The mean placental tissue/maternal plasma concentration ratio of lidocaine was higher than that of bupivacaine (1.45 vs 1.01, P < 0.05). The mean amount of the drug retained in the placenta per unit of dose (mg/kg) was also higher in the lidocaine-epinephrine group, although this difference did not reach statistical significance (0.46 mg/unit dose vs 0.40 mg/unit dose). Values for area under the concentration-time curves per unit of dose were similar. In conclusion, maternal plasma concentrations, fetal/maternal concentration ratios and placental tissue binding of lidocaine resembled those of bupivacaine after epidural administration. These findings are probably explainable by the effect of maternal hypotension on the distribution of lidocaine.

Clinical Trial↗
PubMed1998

[Labor analgesia].

Explore the source record for details and available documents.

Analgesia, Obstetrical↗
PubMed1997

Feto-maternal distribution of ropivacaine and bupivacaine after epidural administration for cesarean section.

Ropivacaine is a new amino amide local anesthetic less lipophilic and with a lower affinity for plasma proteins than bupivacaine. The purpose of this study was to examine the feto-maternal distribution of ropivacaine and bupivacaine after epidural administration for cesarean section. Healthy parturients were randomly allocated in a double-blinded manner to receive either 0.5% ropivacaine or 0.5% bupivacaine through a lumbar epidural catheter. The total and free concentrations of ropivacaine and bupivacaine were determined in the maternal and umbilical plasma. The total dose (mg/kg) required for adequate surgical anesthesia and the resulting maximum total concentrations did not differ significantly between ropivacaine and bupivacaine. The free plasma clearance of bupivacaine was higher than that of ropivacaine (7382 vs 3344 ml/min, P = 0.0001). The apparent terminal elimination half-life of ropivacaine was shorter than that of bupivacaine (6.0 vs 8.8 h, P = 0.007). At delivery, the maternal free plasma concentration of ropivacaine was more than twice that of the free concentration of bupivacaine (0.072 vs 0.032 microg/ml, P = 0.002). The free concentration of ropivacaine was about twice that of bupivacaine in the umbilical venous (0.06 vs 0.03 microg/ml, P = 0.001) and umbilical arterial (0.05 vs 0.02 microg/ml, P = 0.007) plasma. The more rapid plasma clearance of bupivacaine compared to ropivacaine, leading to lower maternal plasma concentrations and hence to lower umbilical concentrations at delivery, could be explained by the higher lipid solubility, hence greater distribution volume, of bupivacaine.

Clinical Trial↗
PubMed1997

A survey of postoperative nausea and vomiting.

A prospective interview-based survey on the incidence of postoperative nausea and vomiting in 1107 in-patients aged 4-86 years was conducted during a 3-month period. Nausea, emetic episodes and the need for anti-emetic medication were recorded for 24 h postoperatively. In the recovery room, the incidence of nausea and vomiting was 18% and 5%, respectively. Over the whole 24-h period, these figures were 52% and 25%, respectively; severe nausea was experienced by 8%. The highest incidence of emetic sequelae was observed in gynaecological patients; 52% of the 822 patients who received general anaesthesia and 38% of the 285 patients who received regional anaesthesia reported nausea. The most important predictive factors associated with an increased risk for nausea and vomiting were female gender, a previous history of postoperative sickness, a longer duration of surgery, nonsmoking and a history of motion sickness. Based on these five items, a simple score predicting the risk of nausea and vomiting was constructed with a moderately good discriminating power.

Adolescent↗
PubMed1997

The anti-emetic efficacy of a combination of ondansetron and droperidol.

The anti-emetic efficacy of a combination of ondansetron 8 mg with either droperidol 0.75 mg or 1.25 mg given prophylactically was studied in a randomised blinded trial of 94 female inpatients with a previous history of postoperative nausea and vomiting and scheduled to have laparoscopic surgery. A standardised general anaesthetic technique was used for all patients. The mean estimated risk of postoperative sickness according to predictive patient characteristics was 65% for both treatment groups. During the 24 h study period, the proportion of patients with nausea was similar (35%) in both groups, and vomiting occurred in 16% and 14% of the patients in the droperidol 0.75 mg and 1.25 mg groups, respectively. No serious adverse events were observed. Ondansetron in combination with droperidol 0.75 mg resulted in less drowsiness than in combination with 1.25 mg (p = 0.03). In conclusion, a prophylactic combination treatment of ondansetron 8 mg with a small dose of droperidol was clinically effective and well tolerated for the prevention of postoperative nausea and vomiting after laparoscopic surgery in patients with a high probability of nausea and vomiting.

Adult↗
PubMed1997

Comparison of ondansetron and droperidol in the prevention of postoperative nausea and vomiting after laparoscopic surgery in women. A randomised, double-blind, placebo-controlled trial.

BACKGROUND: Women undergoing laparoscopic surgery are susceptible to postoperative nausea and vomiting (PONV). Ondansetron and droperidol are useful antiemetics. This study was designed to ascertain primarily the relative difference in efficacy of ondansetron and droperidol and secondarily between these drugs and placebo in the prevention of PONV after laparoscopic surgery. METHODS: The prophylactic antiemetic efficacy of ondansetron and droperidol was compared in a prospective, randomised, double-blind, placebo-controlled trial of 439 female inpatients scheduled for laparoscopic surgery. During induction of standardised general anaesthesia the patients received intravenously either ondansetron 8 mg (n=195), droperidol 1.25 mg (n=193) or placebo (n=51). The occurrence of nausea, vomiting, side-effects and the need for rescue antiemetic medication were recorded for 24 h postoperatively. RESULTS: The proportion of patients with nausea was 48%, 50% and 67% in the ondansetron, droperidol and placebo groups, respectively; with a significant difference when both ondansetron (P=0.02) and droperidol (P=0.04) were compared with placebo. Vomiting occurred in 18%, 26% and 37% of the patients in the three groups, respectively (P=0.05 between ondansetron and droperidol, P=0.004 between ondansetron and placebo, P=0.16 between droperidol and placebo). The proportion of patients given rescue medication was 34%, 28% and 49%, respectively (P=0.23 for ondansetron and droperidol, P=0.07 for ondansetron and placebo, P=0.007 for droperidol and placebo). During early recovery the patients treated with ondansetron were significantly more alert than after droperidol. Serious side-effects were not observed. Headache was significantly more common after ondansetron than after droperidol treatment. CONCLUSIONS: The efficacy of prophylactic ondansetron and droperidol in reducing postoperative nausea associated with laparoscopic surgery in female inpatients was similar, but ondansetron appeared to be slightly more efficient than droperidol in preventing vomiting. Ondansetron and droperidol were both significantly better than placebo in the prophylaxis of PONV.

Adolescent↗
PubMed1996

Maternal and uteroplacental haemodynamic state in pre-eclamptic patients during spinal anaesthesia for Caesarean section.

We have studied the effects of crystalloid (Ringer's acetate 1 litre) preloading and subsequent spinal anaesthesia in 12 pre-eclamptic parturient patients undergoing elective Caesarean section. Maternal placental uterine artery circulation was measured using a pulsed colour Doppler technique with simultaneous measurement of maternal haemodynamic state. Despite preloading, mean maternal systolic arterial pressure (SAP) decreased significantly and marked maternal hypotension (SAP < 80% of baseline value) was recorded in two patients after induction of spinal anaesthesia. Mean central venous pressure increased significantly after preload, but decreased to baseline shortly after induction of spinal anaesthesia. Mean pulsatility index (PI) in the uterine artery did not change during preload or spinal block. In one patient, uterine artery PI increased significantly when SAP decreased to 71% of the baseline value, 14 min after induction of spinal anaesthesia. These results suggest that preload with crystalloid solution does not prevent maternal hypotension in pre-eclamptic patients, and that changes in uterine artery velocity waveforms were minor when SAP was 80% or more of baseline during spinal anaesthesia. These changes did not appear to have any major effect on the clinical condition of the neonate, as assessed by Apgar score and umbilical artery pH values.

Adult↗
PubMed1996

Single bolus compared with a fractionated dose injection technique of bupivacaine for extradural Caesarean section: effect on uteroplacental and fetal haemodynamic state.

We studied 26 healthy parturients undergoing elective Caesarean section, allocated randomly to receive extradural block with 0.5% plain bupivacaine in a double-blind manner in either a single bolus or fractionated doses. After a 3-ml test dose, an additional 20 ml of bupivacaine were given over a 5-min period in the single bolus group (n = 13) and over a 25-min period in the fractionated dose group (n = 13). We studied the effects of bupivacaine on blood flow velocities in the maternal placental and non-placental uterine and fetal umbilical arteries before and four times during establishment of extradural block using a pulsed colour Doppler technique. Median sensory block reached T3 in the single-dose group compared with T4 in the fractionated-dose group. Two subjects in each group required i.v. ephedrine to correct transient hypotension (systolic arterial pressure < 90 mm Hg). Blood flow velocity waveform indices of the uterine and umbilical arteries did not differ significantly within or between groups during the study. There was no significant difference in neonatal outcome, as assessed by Apgar scores and umbilical artery pH values. In conclusion, we observed no deterioration in uteroplacental circulation after administration of a single bolus dose of bupivacaine.

Adult↗
PubMed1996

Preanaesthetic management of the obstetric patient.

The obstetric patient presents unique challenges to the anaesthesiologist. The physiologic changes in the mother during pregnancy and the anaesthetic implications of these changes, associated with the pathophysiologic conditions frequently superimposed on the pregnancy, distinguish the parturient from the other patients about to undergo anaesthesia and surgery. Furthermore, the obstetric patient may be in acute pain from labour and frequently needs urgent surgical intervention because of sudden changes in the condition of the mother or the fetus.

Anesthesia, Obstetrical↗
PubMed1995

Effect of crystalloid and colloid preloading on uteroplacental and maternal haemodynamic state during spinal anaesthesia for caesarean section.

We have studied the effects of crystalloid 1 litre (lactated Ringer's) or colloid 0.5 litre (hydroxyethyl starch) preloading in 26 healthy parturients undergoing elective Caesarean section under spinal anaesthesia. Maternal placental uterine artery circulation was measured using a pulsed colour Doppler technique with simultaneous measurement of maternal haemodynamics. A high incidence of maternal hypotension was observed during spinal anaesthesia in the crystalloid group (62%) but the incidence was lower in the colloid group (38%). Central venous pressure was increased significantly in both groups after preload but decreased shortly after induction of spinal anaesthesia to baseline values. The mean pulsatility index (PI) in the uterine arteries did not change during preload or spinal block. A surprising finding was the widespread variation and some high values for the uterine artery PI after spinal anaesthesia. These individual increases in PI were transient and always returned to baseline values within 2 min. These results suggest that preloading with either solution is ineffective in preventing maternal hypotension and that changes in maternal heart rate, systolic arterial pressure and central venous pressure during spinal anaesthesia were not associated with rapid individual increases in uteroplacental vascular resistance. These changes seemed not to have any major effect, however, on the clinical condition of the newborn, as assessed by Apgar scores and umbilical artery pH values.

Adult↗