Autotransfusion with Predeposit-Haemodilution and Perioperative Blood Salvage: 20 Years of Experience

Background

Through a prospective study, we evaluated the efficacy of an integrated autotransfusion regimen comprised of predeposit-hemodiluition and intra and post-operative blood salvage in major orthopaedic surgery.

Methods

We examined the records of 2303 consecutive patients (1524 females and 779 males, mean age 62.7, standard deviation 11 years (range 16–90 yrs), pre-operative haemoglobin (Hb) concentration 13.5 (SD 1.4) (range 6.7–19.3) g/dl undergong total hip arthroplasty (THA 1582 patients), THA after the removal of internal fixation devices (RFD+THA, 25 patients), total knee arthroplasty (TKA, 347 patients), revision surgery of the hip (HR, cup+stem revision, 248 patients; cup revision 64 patients; stem revision 23 patients) and total knee revision (TKR 14 patients). We estimated that the number of predonations (MSBOS - maximum surgery blood order schedule) was 2 units for THA, TKA and TKR, and 3 units for partial or total hip revision and for total hip arthroplasty with fixation removal.

Results

It was possible to obtain the MSBOS in 2070 patients (89.8%). Homologous red blood cell (HRBC) transfusion were carried out in 184 patients (8%). We found that the need to use HRBC was significantly associated with failure to meet the number of MSBOS, female sex, lower pre-operative Hb concentration, use of calcium heparin for antithrombosis prophylaxis, more extensive surgery, a higher ASA rating and co-existing diseases such as coronary artery disease.

Conclusions

Cooperation among anaesthesis, transfusionists and surgeons in the application of an integrated autotransfusion regimen enabled us to treat 92% of our patients with only autotransfusion.

Intrapartum sonography for occiput posterior detection in early low dose combined spinal epidural analgesia by sufentanil and ropivacaine

AIM

To evaluate the incidence of occiput posterior position in labour with and without combined spinal epidural analgesia (CSE) by low dose of sufentanyl and ropivacaine.

MATERIAL AND METHODS

This study focused on 132 women subdivided in two groups, patients in spontaneous and in labour analgesia, administered by a low dose CSE by sufentanyl and ropivacaine; all women were evaluated by digital examinations and ultrasound till delivery. All data were collected and analyzed by an independent reviewer.

RESULTS

In the second stage, 79 were persistent occiput posterior position (POPP) fetuses and 36 were translated from anterior to posterior position (TAPP) fetuses. Specifically, in spontaneous labour on 25 women in anterior position, there were 17 TAPP and in CSE analgesia on 28 women in anterior, there were 19 in TAPP, without significant differences. The number of asynclitisms was higher in the POPP group (84%) respect to the TAPP group (75%), so as the rate of caesarean section (67% versus 52.7%).

CONCLUSIONS

The labour with low dose of ropivacaine and sufentanyl does not increase the occiput posterior position during fetal descent, leading to a POPP. Finally, since in the occiput anterior presentation labour analgesia significantly lengthens time to delivery, in the occiput posterior position this is significantly increased, with a prolonged second stage of labour and reduced time of descent of fetal head in obstetric pelvis.

Adding sufentanil to levobupivacaine or ropivacaine intrathecal anaesthesia affects the minimum local anaesthetic dose required

BACKGROUND

We carried out this prospective, randomized, double-blind study in order to evaluate whether the intrathecal addition of sufentanil 3.3 mcg affects both the minimum local anaesthetic dose (MLAD) of spinal levobupivacaine and ropivacaine for a caesarean section and enhances the spinal block characteristics.

METHODS

One hundred and eighty women were randomly allocated into four groups: levobupivacaine (Group L), levobupivacaine plus sufentanil (Group L+S), ropivacaine (Group R) and ropivacaine plus sufentanil (Group R+S). Each received 3 ml of the study solution intrathecally as part of a combined spinal/epidural technique. The initial dose was 12 mg for Groups L and L+S, and 15 mg for Groups R and R+S. The test solution was required to achieve a visual analogue pain score (VAPS) of 30 mm or less to be considered effective at skin incision, uterine incision, birth, peritoneal closure and at the conclusion of surgery. Effective or ineffective responses determined a 0.5 mg decrease or increase of the same drug, respectively, for the next patient in the same group, using an up-down sequential allocation.

RESULTS

Using the Dixon and Massey formula, the MLAD was 10.65 mg [confidence interval (CI) 95%: 10.14-11.56] in Group L, 4.73 mg (CI 95%: 4.39-5.07) in Group L+S, 14.12 mg (CI 95%: 13.50-14.60) in Group R and 6.44 mg (CI 95%: 5.86-7.02) in Group R+S.

CONCLUSIONS

The addition of sufentanil reduced the MLAD of both the local anaesthetics. It did not affect their potency ratio significantly and resulted in enhanced spinal anaesthesia.

Long-term epidural analgesia treatment in pre-eclamptic women: a preliminary trial

Pre-eclampsia (PE) is a clinical pregnancy-related condition, characterised by an elevated blood pressure and proteinuria. The author treated selected cases of PE with long-term epidural analgesia (LTEA), that reduced labour pain and operated directly on the PE aetiopathogenesis, not on the symptoms. A total of 15 women with PE were hospitalised at 35-37 weeks of pregnancy, checked for blood pressure, liver and renal function, platelet count and had an epidural catheter inserted for a continuous administration of an analgesic mixture of Naropin, Sufentanil and Clonidine. The average weeks at delivery were 37 weeks and 1 day; 10 women had a spontaneous delivery and five a caesarean section: the mean birth weight was 2,906 g and the Apgar scores at 1 min and 5 min exceeded 7 in all cases. All the parameters improved after hospital admission and at discharge. All the patients were discharged in good condition and no patients needed supplementary antihypertensive treatment. The LTEA utilisation for 1 week is well tolerated and improves uteroplacental perfusion, but further studies and a larger number of patients are required to evaluate this pharmacological procedure and determine its place in the management of PE.

Efficacy and comparison of 0.5% levobupivacaine with 0.75% ropivacaine for peribulbar anaesthesia in cataract surgery

BACKGROUND AND OBJECTIVE

The low cardiovascular and neurological toxicity of levobupivacaine has led to its application as a local anaesthetic in a wide variety of specialist applications including peribulbar block for cataract surgery. The aim of this study was to evaluate the efficacy of levobupivacaine 0.5% and to compare block quality vs. ropivacaine 0.75% in peribulbar anaesthesia.

METHODS

We examined 208 patients subjected to cataract surgery by phacoemulsification who were randomized into two groups according to the anaesthetic used for peribulbar block, namely levobupivacaine 0.5% or ropivacaine 0.75%, both with the addition of hyaluronidase. Nerve block was carried out by injection of 6 mL of the anaesthetic mixture equally distributed between the inferotemporal and superonasal areas. The success of the block was evaluated by determining the time of motor and sensory onset, akinesia score, times of motor and sensory offset and satisfaction of the patient and surgeon after 24 h. Pre-block, post-block and postoperative intraocular pressure as well as the duration of surgical intervention was also determined.

RESULTS

With respect to ropivacaine, levobupivacaine showed a significant reduction (P < 0.001) in the average motor and sensory onset. Both the akinesia score (P < 0.01) and mean motor and sensory offset times were also higher (P < 0.001). Neither the average intervention times nor the satisfaction of the patient/surgeon showed any significant differences between the two groups.

CONCLUSIONS

Levobupivacaine (0.5%) has better anaesthetic properties with respect to 0.75% ropivacaine and is well-suited for peribulbar block in cataract surgery.

Minimum local anaesthetic dose (MLAD) of intrathecal levobupivacaine and ropivacaine for Caesarean section*

We determined the minimum local anaesthetic dose (MLAD) of spinal levobupivacaine and ropivacaine for Caesarean section. Ninety women were randomly allocated to two groups and received 3 ml of study solution by a combined spinal/epidural technique. The initial dose was 12 mg for levobupivacaine and 17 mg for ropivacaine groups. To be considered effective, a test solution had to achieve a visual analogue pain score (VAPS) of 30 mm or less at skin incision, uterine incision, birth, peritoneal closure, and at the end of surgery. Effective or ineffective responses determined, respectively, a 0.3 mg decrease or increase of the same drug for the next patient in the same group, using up-down sequential allocation. The MLAD of levobupivacaine was 10.58 mg (CI 95%: 10.08-11.09) and the MLAD of ropivacaine 14.22 mg (CI 95%: 13.67-14.77), using the Dixon and Massey formula. The potency ratio between spinal levobupivacaine and spinal ropivacaine was 1.34.

Propofol and thiopentone for caesarean section revisited: maternal effects and neonatal outcome

In 56 women undergoing elective caesarean section, general anaesthesia was induced with either propofol 1% or thiopentone 2.5% followed by 50% nitrous oxide in oxygen and isoflurane 0.75% until delivery. In the thiopentone group the arterial pressure rose following tracheal intubation and skin incision, while in the propofol group there was a significant tendency to hypotension immediately following induction of anaesthesia. There were differences in electroencephalogram (EEG) between the groups, while laryngoscopy, intubation and surgical stimulation had no effect on EEG pattern. Recovery after anaesthesia did not differ between groups. None of the patients had recall of the intraoperative period, but 53% of patients induced with propofol showed signs of light anaesthesia between induction and delivery. Neonates in the propofol group had lower Apgar scores 1 min after birth than those in the thiopentone group, but these differences were no longer significant at 5 min. No differences were noted in neurobehavioural status at 1, 4 and 24 h.

Comparison of fentanyl with clonidine as adjuvants for epidural analgesia with 0.125% bupivacaine in the first stage of labor: a preliminary report

48 primiparae received epidural analgesia in labor with 10 ml of 0.125% bupivacaine with epinephrine 1:800 000, and then were divided in 4 equal groups (n = 12) to receive one of the following: 5 ml saline (B); 100 mug of fentanyl (BF); 150 microg of clonidine (BC); 75 microg of clonidine and 50 microg of fentanyl (BCF). All the patients had satisfactory analgesia. Onset was similar in the 4 groups but the duration of analgesia was significantly prolonged by the addition of either 100 microg of fentanyl or 150 microg of clonidine (respectively 89.8 min and 92.5 min vs 62.5 min) (P < 0.0001). The addition of both clonidine (75 microg) and fentanyl (50 microg) produced a considerably prolonged analgesia (177.5 min) (P < 0.0001). No episodes of bradycardia were observed. Hypotension, reversed by i.v. ephedrine, occurred in 2 patients of BCF group and in 1 patient of BF and BC groups. Only patients receiving fentanyl had pruritus. Both fentanyl and clonidine produced sedation, but both incidence and severity were greater with the mixture. No differences in neonatal outcome assessed by Apgar scores and NACS, were observed.

High volume of subarachnoid levobupivacaine decreases drug requirement in first stage labor analgesia

AIM

Using the statistic method of sequential allocation, we realized a prospective double-blind study in order to establish the minimum local anesthetic concentration (MLAC) of large intrathecal volume of levobupivacaine, during the first stage labour analgesia in spontaneous and induced laboring women.

METHODS

Seventy-five nulliparous, at term, with cervical dilatation <5 cm parturients requesting combined spinal/epidural analgesia, were enrolled. The starting concentration was chosen according to recent literature. Total volume of study solution was 10 ml and efficacy was assessed with a visual analogue pain scale at the height of the uterine contraction.

RESULTS

We established that MLAC of levobupivacaine, in 10 ml intrathecal volume, during the first stage of spontaneous and induced labour was 0.0134% and 0.0195%, respectively. No complications occurred during the study and the only side effect was shivering, which is common even in other anesthetic techniques. We produced a very selective sensitive block. Neither sympathetic nor motor block occurred.

CONCLUSIONS

Low intrathecally concentration of local anesthetic allows the anesthetist to reduce the total amount of drug and improves not only the differential blockade between motor and sensitive but also between sympathetic and sensitive fibers.

Postpartum cerebral ischaemia after accidental dural puncture and epidural blood patch

Puerperal women are reported to have a rate of cerebral infarction 13 times greater than non-pregnant females. We report a case of cerebral ischaemia in a 30-yr-old healthy parturient after epidural analgesia for labour, complicated by dural puncture treated with two epidural blood patches. Investigations showed the development of cerebral ischaemia on postpartum day 14. A transcranial Doppler ultrasonography showed vasospasm of the left middle cerebral artery still present at 3-month follow-up. At 1-yr follow-up, the patient had homonymous hemianopsia. We discuss the possible causative mechanism of the cerebral ischaemia in relation to the dural puncture and epidural blood patch.

[Epidural vs general anaesthesia]

BACKGROUND

Aim of this study is to determine if and how the anaesthesia technique can significantly influence the outcome in patients after major orthopaedic surgery in terms of: patrimony of red blood cells (blood loss and erythropoiesis), incidence of intra and postoperative complications, postoperative pain control and hospital stay.

METHODS

210 patients, ASA physical status I-III, undergoing elective primary total hip replacement were randomly allocated in three groups of 70 patients to receive either epidural anaesthesia (Group EA), general anaesthesia (GA), or epidural anaesthesia integrated with mild general anaesthesia (IA).

RESULTS

Data show a significant difference between the amount of pain measured by VRS immediately after surgery: prevalently absent in groups IA (84.3%) and EA (85.7%) and prevalently severe and moderate in group AG (34.3%). The measurement of the basic circulating erythrocyte mass in the first, third and fifth postoperative day, calculated by the Mercuriali formula, which considers blood loss, autologous and homologous transfusions and erythropoiesis, showed that general anaesthesia leads to a significant delay in the resumption of haemopoiesis. This result was attenuated by its combination with epidural anaesthesia.

CONCLUSIONS

On the basis of the literature and the results of our study, epidural anaesthesia seems to be the most appropriate technique for patients scheduled for total hip replacement: due to its simpler analgesic cover, its tendency to be associated with a lower incidence of complications in the first 24 hours after surgery. The incidence of relevant hypotension is minor compared to integrated anaesthesia. General anaesthesia produced a significant decrease in postoperative erythropoiesis.

Intraoperative fetal oxygen saturation during Caesarean section: general anaesthesia using sevoflurane with either 100% oxygen or 50% nitrous oxide in oxygen

BACKGROUND AND OBJECTIVE

The study was designed to evaluate whether the administration of sevoflurane in 100% oxygen for anaesthesia during Caesarean section would improve fetal and neonatal oxygenation compared with the administration of sevoflurane with 50% nitrous oxide in oxygen.

METHODS

The randomized, single-blind controlled study examined 24 mothers, ASA I-II, at term undergoing Caesarean section who were allocated to receive sevoflurane in either 100% oxygen (n = 13) or 50% nitrous oxide in oxygen (n= 11). General anaesthesia was induced in both groups with thiopental 4-5 mg kg(-1) followed by succinylcholine 1.5 mg kg(-1) to facilitate tracheal intubation. Parturients received sevoflurane given either in 100% O2 or in a 50:50 nitrous oxide and oxygen mixture, using 0.5-1.0% progressive incremental dosing up to 1.5-2.0 MAC. Non-invasive fetal oxygen saturation was measured between induction to delivery, and umbilical artery and vein PaO2 were evaluated at birth.

RESULTS

Intraoperative fetal oxygen saturation increased in all patients after maternal 100% oxygen administration (P < 0.01). Maternal hyperoxygenation significantly increased the umbilical vein and umbilical artery PaO2 and the umbilical artery SaO2 at birth (P < 0.0001).

CONCLUSIONS

Maternal hyperoxygenation significantly improves fetal as well as neonatal oxygenation.

[Prehydratation and anaesthesia in obstetrics: state of the art]

All epidural or spinal techniques using local anaesthetics causes some degree of sympathetic blockade resulting in peripheral vasodilatation and possibly hypotension or reduction in cardiac output. In the practical clinic, administration of fluids intravenously prior spinal and epidural anaesthesia is required to prevent maternal hypotension and fetal hypoxia. We evaluated in this review the efficacy of volume preloading on the incidence of hypotension after spinal or epidural anaesthesia for caesarean delivery. Randomized controlled trials investigating volume preloading before the initiation of obstetric anaesthesia were sought by using MEDLINE (1966-2001). The primary outcome was the incidence of hypotension. Secondary outcomes included: ephedrine use, Apgar scores, umbilical cord pH values, and maternal nausea and vomiting. Crystalloid preload was inconsistent in preventing hypotension, whereas colloid appeared to be effective in all studies. A colloid solution, such as hydro-xyethyl starch (HES) might be preferable considering the capacity to stay intravasculary for a longer period. Few differences in fetal outcomes or maternal nausea and vomiting were reported. Increasing central blood volume by using colloid decreases the incidence of hypotension before loco-regional anaesthesia for cesarean delivery. Implications. We performed a review to determine whether fluid loading reduced the incidence of low blood pressure after spinal or epidural anaesthesia for caesarean delivery. Although no technique totally eliminates the occurrence of hypotension, colloid administration (starch or gelatin containing fluids) was the most effective.

[Motor block determination for the identification of accidental spinal injection of levobupivacaine: a study on the minimum efficient test-dose (ED50)]

BACKGROUND

The aim of this study was to determine the ED50 for the dose of levobupivacaine 0,5% that, if given intrathecally will not cause total spinal anesthesia but will give a reliable and reproducible clinical sign to differentiate intrathecal from epidural injection.

METHODS

Thirty women at term undergoing elective cesarean section under a combined spinal-epidural technique (CSE) were enrolled into this sequential allocation study. The dose in each test dose was determined by the response of the previous patient to the higher or lower dose in her test syringe, according to up-down sequential allocation. The exception to this was the first woman in each group, for whom the starting dose was chosen to be 4 mg. The end point was the occurrence of any motor block, in any side, within 5 minutes from intrathecal injection of the test dose. Test dose efficacy was assessed using a modified Bromage scale every minute for 5 minutes. The median effective dose of levobupivacaine was estimated from the up-down sequences using the formula of Dixon and Massey.

RESULTS

The MAD of the test dose for levobupivacaine was of 4,8 mg (4,4 to 5,2; 95% C.I.).

DISCUSSIONS

This study may help to determine the appropriate dose for a test dose for inadvertent spinal levobupivacaine.

[Levobupivacaine in obstetric analgesia and anaesthesia]

METHODS

Published studies, including abstracts, has been reviewed and summarized.

RESULTS

Studies in sheep have demonstrated no significant differences in pharmacokinetic and placental transfer of levobuvacaine when compared with bupivacaine. Clinical studies on cesarean section confirmed similar performance between these two drugs. No differences in onset time, sensory and motor block and efficacy of analgesia have been reported. Two multicentre studies on labor analgesia reported again similar analgesic efficacy with a trend toward less motor block in parturients receiving levobupivacaine.

CONCLUSIONS

This review has shown that levobupivacaine has a similar efficacy and a similar maternal fetal safety to that of bupivacaine. Further studies are needed to determine if the chemical properties of the new agent may influence the sensory and motor characteristics of the block.

Minimum analgesic dose of epidural sufentanil for first-stage labor analgesia: a comparison between spontaneous and prostaglandin-induced labors in nulliparous women

BACKGROUND

The aim of this prospective, double-blind, sequential allocation study was to compare the effects of spontaneous and prostaglandin-induced labor on the minimum analgesic dose of epidural sufentanil in the first stage of labor.

METHODS

Seventy healthy, nulliparous women, at more than 37 weeks' gestation with cervical dilatation from 2 to 4 cm, requesting epidural pain relief in labor were enrolled. The subjects were assigned to two different groups according to whether labor was spontaneous or induced with dinoprostone 0.5 mg. Parturients received 10 ml of the study solution through a lumbar epidural catheter. The initial dose was sufentanil 25 microg, and subsequent doses were determined by the response of the previous patient in the same group using up-down sequential allocation. The analgesic effectiveness was assessed using 100-mm visual analog pain scores. The up-down sequences were analyzed using the method of independent paired reversals and probit regression.

RESULTS

The minimum analgesic dose of sufentanil in spontaneous labor was 22.2 microg (95% CI: 19.6, 22.8) and 27.3 microg (95% CI: 23.8, 30.9) in induced labor. The minimum analgesic dose of sufentanil in induced labor was significantly greater (P = 0.0014) than that in spontaneous labor (95% CI difference: 2.9, 9.3) by a factor of 1.3 (95% CI: 1.1, 1.5).

CONCLUSION

Prostaglandin induction of labor produces a significantly greater analgesic requirement than does spontaneous labor.

SCS in intractable angina

Despite a wide range of therapeutic choice in the treatment of angina pectoris, there is a small but increasing population of patients that doesn't benefit of conventional therapy and whose life is invalidated by frequent attack of anginal pain. For this population, nonresponders to drug therapy not suitable for revascularization (coronary bypass surgery, angioplasty), neurostimulation of dorsal column has been described as an effective and safe therapy. The mechanism of action is not completely known, but is safety is sufficiently established. It may become a useful choice in the treatment of patients with intractable angina.

A comparison between low-dose ropivacaine and bupivacaine at equianalgesic concentrations for epidural analgesia during the first stage of labor

The aim of this study was to evaluate the efficacy, onset and duration of analgesia of two equianalgesic epidural doses of ropivacaine and bupivacaine during the first stage of labor. The study included 190 healthy nulliparous parturients who presented spontaneous onset of labor and required epidural analgesia. They were divided randomly to receive epidural analgesia with an initial dose 0.10% ropivacaine or 0.0625% bupivacaine 20 mL both with the addition of 10 microg of sufentanil. There were no significant differences in onset time, quality of analgesia, maternal hypotension and ability to ambulate. Ropivacaine produced more prolonged analgesia then bupivacaine (89 vs 119 min;P<0.0003). The clinical value of this prolonged analgesia after the first dose needs further evaluation when a continuous infusion technique is used.

Autotransfusion with predeposit-haemodilution and perioperative blood salvage: 20 years of experience. Rizzoli Study Group on Orthopaedic Anesthesia

BACKGROUND

Through a prospective study, we evaluated the efficacy of an integrated autotransfusion regimen comprised of predeposit-hemodiluition and intra and post-operative blood salvage in major orthopaedic surgery.

METHODS

We examined the records of 2303 consecutive patients (1524 females and 779 males, mean age 62.7, standard deviation 11 years (range 16-90 yrs), pre-operative haemoglobin (Hb) concentration 13.5 (SD 1.4) (range 6.7-19.3) g/dl undergong total hip arthroplasty (THA 1582 patients), THA after the removal of internal fixation devices (RFD+THA, 25 patients), total knee arthroplasty (TKA, 347 patients), revision surgery of the hip (HR, cup+stem revision, 248 patients; cup revision 64 patients; stem revision 23 patients) and total knee revision (TKR 14 patients). We estimated that the number of predonations (MSBOS - maximum surgery blood order schedule) was 2 units for THA, TKA and TKR, and 3 units for partial or total hip revision and for total hip arthroplasty with fixation removal.

RESULTS

It was possible to obtain the MSBOS in 2070 patients (89.8%). Homologous red blood cell (HRBC) transfusion were carried out in 184 patients (8%). We found that the need to use HRBC was significantly associated with failure to meet the number of MSBOS, female sex, lower pre-operative Hb concentration, use of calcium heparin for antithrombosis prophylaxis, more extensive surgery, a higher ASA rating and co-existing diseases such as coronary artery disease.

CONCLUSIONS

Cooperation among anaesthesis, transfusionists and surgeons in the application of an integrated autotransfusion regimen enabled us to treat 92% of our patients with only autotransfusion.

Relative potencies of bupivacaine and ropivacaine for analgesia in labour

We have used the technique of randomized, double-blind sequential allocation to compare the minimum local analgesic concentrations (MLAC) of epidural bupivacaine and ropivacaine for women in the first stage of labour. The test bolus was 20 ml of local anaesthetic solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of local anaesthetic, according to up-down sequential allocation. Efficacy was assessed using a 100-mm visual analogue pain score (VAPS). The test solution had to achieve a VAPS of 10 mm or less to be judged effective. For bupivacaine, MLAC was 0.093 (95% CI 0.076-0.110)% w/v, and for ropivacaine, 0.156 (95% CI 0.136-0.176)%w/v (P < 0.0001, 95% CI difference 0.036-0.090). The analgesic potency of ropivacaine was 0.60 (0.47-0.75) relative to bupivacaine. Claims for reduced toxicity and motor block must be considered with differences in analgesic potency in mind.

Regional blocks for cesarean section

Recent researches in the field of regional anesthesia for cesarean section have focused on spinal anesthesia, including prophylaxis of maternal hypotension, the use of opioids to improve intra- and postoperative analgesia and the use of ropivacaine.

Minimum local analgesic concentration of extradural bupivacaine increases with progression of labour

We have used the technique of double-blind sequential allocation to quantify the minimum local analgesic concentration (MLAC) of extradural bupivacaine for women in early (median cervical dilatation 2 cm) and late (median cervical dilatation 5 cm) labour. The first bolus was 20 ml of the bupivacaine test solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of bupivacaine according to up and down sequential allocation. Efficacy was assessed using a 100-mm visual analogue pain score (VAPS). The test solution had to achieve a VAPS of 10 mm or less to be judged effective. In early labour, the MLAC of bupivacaine was 0.048% w/v (95% confidence intervals (CI) 0.037-0.058% w/v), and 0.140% w/v (95% CI 0.132-0.150% w/v) in the late group. The MLAC of bupivacaine in late labour was greater by a factor of 2.9 (95% CI 2.7-3.2) compared with the MLAC in early labour (P < 0.0001, 95% CI difference 0.08-0.11). We conclude that advancing labour requires an increased concentration of extradural bupivacaine for pain relief.

Anatomy of the lumbar epidural region using magnetic resonance imaging: a study of dimensions and a comparison of two postures

Many techniques used to investigate the epidural region may alter the anatomy. Magnetic resonance imaging (MRI) has been introduced as a non-invasive diagnostic technique. The aim of this study was to investigate the anatomy of the lumbar epidural region using MRI, studying the morphology, the dimensions and the modification that may result from a change of position. Ten young, healthy female volunteers were studied to obtain results relevant to obstetric anesthesia. The following measurements were made: anterior epidural space (AES); posterior epidural space (PES); ligamenta flava; distance between the PES and the skin (S-ES); and interspace distance (ISD). All these distances were measured with the subject supine and the lumbar spine either in a neutral or a non-lordotic (flexed) position. The S-ES ranged from 2.7 to 8.1 cm. This distance was greater in the lower than in the upper lumbar segments. No differences were observed in AES, PES and ligamenta flava between the neutral and flexed positions. Flexion of the spine did not affect the S-ES but increased the ISD (P < 0.05). The S-ES at any lumbar segment or interspace and the thickness of ligamenta flava at the L2/3 interspace correlated significantly with body weight (respectively, P < 0.01 and P < 0.02). In conclusion, MRI may clearly reveal the anatomy of the epidural region. The circumferentially and metamerically segmented compartments of the epidural space were clearly noted and measured. Ligamenta flava seem to be thinner in younger than in older subjects. This may partly explain a reduced loss of resistance sometimes perceived in obstetric patients.

Maternal expectations and experiences of labour pain and analgesia: a multicentre study of nulliparous women

Six hospitals with large maternity units in five different European countries were involved in this multicentre study. At least 100 primiparae for each country were examined. All mothers received two standardized interviews, one during the last month of pregnancy, and one 24 h after delivery. Maternal expectations and experiences of pain, pain relief, and satisfaction with analgesia and childbirth were assessed by a 100 mm visual analogue scale (VAS). Almost all mothers were seen regularly by an obstetrician or a midwife during pregnancy, had prepared childbirth classes and received antenatal information on labor analgesia techniques. Differences between the five groups were noted in the level of education and socio-economic status. Maternal expectations of labor pain and the answers to the pre-delivery interview varied significantly between the centers, as did maternal knowledge, expectation and ultimate choice of analgesic technique. Generally speaking the level of maternal satisfaction with analgesia and childbirth experience was high; however, epidural analgesia was more effective than other methods of pain relief (P<0.0001). The most satisfied mothers were those who expected more pain, were satisfied with the analgesia received and had good pain relief after analgesia (P<0.001).

Alkalinization of local anesthetics. Which block, which local anesthetic?

BACKGROUND AND OBJECTIVES

A number of clinical studies have been performed in an attempt to establish the effects of alkalinization on potency of local anesthetics. Conflicting results were obtained probably because different studies used different methods as well as different definitions of the effects. To determine the efficacy of alkalinization using different local anesthetic solutions and different regional blocks, 180 patients were studied in a randomized, double-blind fashion. The local anesthetic solutions studied were bupivacaine, mepivacaine, and lidocaine; the regional blocks studied were epidural block, axillary brachial plexus block, and femoral and sciatic nerve block.

MATERIALS AND METHODS

In this study, 180 patients receiving epidural block (n = 60), sciatic and femoral nerve block (n = 60), and brachial plexus block (n = 60) were randomized to receive, in a double-blind fashion, a plain or a pH-adjusted solution of 2% mepivacaine, 2% lidocaine, or 0.5% bupivacaine. Onset of sensory analgesia, onset of maximum effect (peak effect or complete analgesia), duration of the block, onset, duration and density of motor block were evaluated using pinprick (Hollmen scale) and a 10-point decimal scale (Seow scale).

RESULTS

concerning epidural block, the alkalinization of the local anesthetic shortened significantly the onset of sensory analgesia in the dermatome corresponding to the lumbar interspace used for epidural puncture (L3-L4) and increased the spread of the epidural block in all the groups. The onset of sensory analgesia at L4 level ranged from 10 minutes for plain bupivacaine to 3 minutes for alkalinized lidocaine, whereas the onset at T10 level ranged from 16 minutes for plain bupivacaine and mepivacaine to 12.3 minutes for alkalinized lidocaine. The effects of alkalinization were more evident with lidocaine and bupivacaine. Concerning femoral and sciatic nerve blocks, a statistically significant shorter onset of sensory analgesia and motor block were observed with mepivacaine. Concerning brachial plexus axillary block, the effects of alkalinization were more evident with lidocaine.

CONCLUSIONS

Alkalinization produced the best results with lidocaine and bupivacaine for epidural block, with lidocaine for brachial plexus block, and with mepivacaine for sciatic and femoral nerve blocks.

Addition of clonidine to epidural morphine enhances postoperative analgesia after cesarean delivery

BACKGROUND AND OBJECTIVES

The randomized, double-blind, dose-response study was designed to evaluate the effects of the addition of clonidine to epidural morphine on postoperative analgesia and side effects in patients undergoing cesarean delivery.

METHODS

Sixty patients, undergoing cesarean delivery under epidural anesthesia, were randomly divided in three equal groups to receive, at the end of surgery, an epidural analgesic mixture consisting of 10 mL solution containing 2 mg of morphine diluted with 0.125% bupivacaine plus 1:800,000 epinephrine and 0, 75, or 150 micrograms of clonidine. Duration of analgesia was assessed as the pain-free interval between the end of surgery and patient's first analgesic request. The analgesic mixture was repeated, on patient's request, to 36 hours after the operation. Arterial blood pressure, heart rate, respiratory rate, and side effects were noted. The total amount of morphine and clonidine delivered was also noted.

RESULTS

The addition of clonidine (0, 75, or 150 micrograms) to morphine significantly increased the duration of postoperative analgesia (P < .0001) (6.27 versus 13.25 and versus 21.55 hours) and reduced the mean total dose of morphine (9.40 mg versus 5.0 mg versus 3.60 mg) (P < .0001). No significant differences in side effects were noted.

CONCLUSIONS

A low dose of clonidine such as 75 micrograms doubled the duration of analgesia produced by 2 mg of morphine and a dose of 150 micrograms further increased the duration of postoperative complete analgesia without increasing the incidence of side effects. The morphine requirements during the postoperative period (36 hours) was greatly reduced by the addition of clonidine to the analgesic epidural mixture.

IV clonidine for post-extradural shivering in parturients: a preliminary study

We have studied the efficacy of i.v. clonidine to suppress post-extradural shivering in parturients. Forty healthy parturients who received extradural block for labour (n = 20) or for Caesarean section (n = 20) and who required treatment for shivering after delivery were allocated randomly to two groups. Group I received i.v. clonidine 30 micrograms diluted in saline to a total volume of 5 ml (therapeutic solution). This bolus was repeated every 5 min if the initial therapy produced no improvement, up to a maximum dose of 90 micrograms. Group II received saline 5 ml (placebo solution), repeated every 5 min if the initial bolus produced no improvement, up to a maximum of three boluses. After 15 min of observation, patients in group I received the placebo solution and those in group II received the study solution. All patients who received clonidine improved, and 75% ceased to shiver within 5 min after only one dose of clonidine 30 micrograms. In contrast, none of the patients treated with saline improved. When patients in the placebo group received clonidine, improvement occurred. Arterial pressure, heart rate, core and peripheral temperature and oxygen saturation did not differ significantly between and within the groups before and after administration of clonidine. We conclude that a small dose of i.v. clonidine may be useful to suppress post-extradural shivering in parturients.

An anatomic study of the effects of dural puncture with different spinal needles

BACKGROUND AND OBJECTIVES

The purpose of this study is to evaluate the effects of puncture of lumbar dura mater with needles of different sizes and with bevels of different shapes.

METHODS

After removal, the dura was punctured with different needles (22-, 25-, 27-, and 29-gauge Quincke, 24-gauge Sprotte, 22-gauge Whitacre, and 18-gauge Tuohy needles) and observed by stereomicroscope to examine the gross morphology. Histologic features were observed by light microscope using frozen and fixed samples stained with hematoxylin and eosin or specific methods (Masson and Weigert) to evidence elastic or collagen fibers.

RESULTS

Puncture hole size was proportional to the size of the needle used. Quincke type needles determined oval or ellipsoidal holes; pencil-point needles determined more rounded holes. Dural retraction determined a reduction of the holes in all cases. Histologic examination revealed an irregular border of the hole, with sectioned as well as compressed fibers. The pattern of compressed but not sectioned fibers was observed more frequently in the samples punctured by pencil-point needles.

CONCLUSIONS

This study confirms that the arrangement of dural fibers is not as uniform as previously thought. Histologic findings confirm the current opinion that pencil-point needles may be less traumatic than Quincke-type needles. The direction of the bevel of the needle does not appear to have great importance in determining the shape of the hole.

Which induction drug for cesarean section? A comparison of thiopental sodium, propofol, and midazolam

STUDY OBJECTIVE

To determine maternal and neonatal effects of three different induction drugs (thiopental sodium, propofol, and midazolam) for cesarean section.

DESIGN

Randomized, double-blind study.

SETTING

Inpatient obstetric department at a general hospital.

PATIENTS

90 healthy patients undergoing elective cesarean section with general anesthesia.

INTERVENTIONS

3 groups of 30 patients each receiving thiopental 5 mg/kg, propofol 2.4 mg/kg, or midazolam 0.3 mg/kg for induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Time to induce anesthesia, hemodynamic changes, depth of anesthesia, recovery after anesthesia, placental transfer, and neonatal outcome (Apgar and neurobehavioral examinations) were studied. In the thiopental and midazolam groups, systolic blood pressure and heart rate rose following endotracheal intubation and skin incision (p < 0.001 and p < 0.0025, respectively), while in the propofol group, there was significant hypotension after induction (p < 0.005). Electroencephalographic patterns showed a light depth of anesthesia with propofol and midazolam between anesthesia induction and delivery, confirmed by the presence of clinical signs of light anesthesia in 50% of propofol patients and 43% of midazolam patients. Time to induce anesthesia was longer with midazolam (p < 0.0001). Neonates in the midazolam and propofol groups had lower Apgar and neurobehavioral scores than those in the thiopental group. Umbilical artery to umbilical vein ratios were above 1 in the propofol and midazolam groups.

CONCLUSION

Thiopental still remains the first-choice induction drug for cesarean section. The slow induction time with midazolam may put the mother at risk for pulmonary inhalation. A plane of anesthesia that may risk awareness and potential neonatal depression is the main drawback of the two newer induction drugs.

Alkalinization improves the quality of lidocaine-fentanyl epidural anaesthesia for caesarean section

This double-blind randomized study of 116 healthy women was undertaken to evaluate whether alkalinization potentiated the analgesic effects of epidural fentanyl-lidocaine for elective Caesarean section. After a test-dose of 3 ml, lidocaine 2% with adrenaline 1:200,000, all patients received 100 micrograms, fentanyl in 5 ml saline and they were then divided into two groups, to receive incremental doses of 5 ml lidocaine 2% with adrenaline 1:200,000 with or without 0.1 mEq.ml-1 sodium bicarbonate, to obtain anaesthesia to T4. The addition of bicarbonate to lidocaine resulted in a mean (SD) pH increase from 6.58 (0.01) to 7.14 (0.02) and in a mean PCO2 increase from 3.8 (0.8) to 345.1 (5.9) mmHg. Onset of sensory analgesia to the S1 segment as well as the interval between the block and the delivery of the baby were shorter in the bicarbonate group (respectively 15.4 (6.9) vs 18.9 (4.8) min and 28.9 (9.5) versus 33.9 (11.8) min; P < 0.01 and 0.05). No differences were noted in the onset to T4 or in the degree of motor block. The percentage of patients experiencing pain during surgery and requiring intravenous analgesics was higher in the group which did not receive bicarbonate (3% vs 16%; P < 0.05). There were no differences in intraoperative maternal side-effects, neonatal outcome or in maternal venous and umbilical venous and arterial lidocaine concentrations between the groups. The concentrations of fentanyl in maternal plasma, umbilical artery, and the umbilical artery to maternal vein ratio were greater in the alkalinized group (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Ventilatory effects of subarachnoid fentanyl in the elderly

Twenty-eight elderly patients scheduled for urological surgery were randomly assigned to receive, in a double-blind study, subarachnoid hyperbaric bupivacaine 15 mg with 50 micrograms (group A, n = 7), 25 micrograms (group B, n = 7), or 12.5 micrograms (group C, n = 7) of fentanyl or 1 ml of saline (group D, n = 7) in a total volume of 4 ml. The pattern of breathing and the ventilatory response to CO2 were studied before and 90, 150 and 480 min after the subarachnoid injection. In group A, mild pruritus and sedation occurred in five patients, while nausea, vomiting and periodic breathing occurred in two. In group B, mild pruritus and sedation were observed in four patients, while nausea and vomiting occurred in two. No significant differences in minute ventilation, respiratory drive and respiratory timing were observed between the groups. Patients receiving fentanyl 50 micrograms showed a percentual change from baseline values as function of time (slope VE/PE'CO2) significantly below baseline at 90 and 150 min (p less than 0.05). However, the baseline values in this group reverted after 480 min. No side effects were observed in groups C or D. It is concluded that subarachnoid fentanyl 50 micrograms can cause an early respiratory depression and its use as a postoperative analgesic should be avoided in the elderly.

Epidural mepivacaine for cesarean section: effects of a pH-adjusted solution

STUDY OBJECTIVE

To determine the clinical effects of the alkalinization of 2% mepivacaine with epinephrine used for epidural block during cesarean section.

DESIGN

Randomized, double-blind, placebo-controlled (standard commercial preparation of 2% mepivacaine with epinephrine) study.

SETTING

Inpatient obstetric department at a general hospital.

PATIENTS

Seventy patients scheduled for elective cesarean section under epidural anesthesia.

INTERVENTIONS

Two groups of 35 patients each receiving either the standard commercial preparation of mepivacaine or the pH-adjusted solution (prepared with the addition of 0.1 meq/ml of sodium bicarbonate to the standard commercial solution).

MEASUREMENTS AND MAIN RESULTS

Measurements of sensory (pinprick) and motor (Bromage's criteria) block were taken at 1- to 2-minute intervals beginning after the completion of the epidural injection. Increasing the pH of the mepivacaine resulted in a significant shortening of the time of analgesia onset (9.3 minutes compared with 16.01 minutes, p less than 0.01) and of peak effect (11.1 minutes compared with 21.2 minutes, p less than 0.01). The alkalinization did not affect duration of the block, intensity of motor block, or mean dose of local anesthetic used.

CONCLUSION

The alkalinization allowed the surgery to proceed more rapidly, significantly decreasing the time interval between epidural block and delivery of the infant.

[Post-operative analgesia with sub-arachnoid fentanyl: ventilatory effects in elderly patients]

Twenty eight elderly patients scheduled for urologic surgery were randomly assigned to receive in a double blind fashion subarachnoid hyperbaric bupivacaine 15 mg with the addition of 50 micrograms (group A, n = 7), 25 micrograms (group B, n = 7), 12.5 micrograms (group C, n = 7), of fentanyl or 1 ml of saline (group D, n = 7) for a total volume of 4 ml. The pattern of breathing and the ventilatory response to CO2 were studied before 90, 150, 480 minutes after the subarachnoid injection. In group A mild pruritus and sedation occurred in 5 patients, nausea, vomiting and periodic breathing occurred in 2 patients. In group B mild pruritus and sedation were observed in 4 patients, nausea, vomiting in 2 patients. No significant changes in VE, Vt/Ti and Ti/Ttot were observed between the groups. Patients receiving 50 micrograms of fentanyl showed a slope VE/PET CO2 significantly below baseline values at 90 and 150 minutes (p less than 0.05). In this group the baseline values were restored after 480 minutes. No side effects were observed in group C and D. 25 micrograms fo fentanyl is the only dose with a significant analgesic effect without any respiratory depression.

Epidural analgesia during and after cesarean delivery. Comparison of five opioids

A randomized, double-blind study was designed to determine the effects on maternal intraoperative analgesia of adding one of the following opioids to the local anesthetic at the onset of epidural block, before surgery and neonatal delivery: morphine (3 mg), fentanyl (75 micrograms), sufentanil (50 micrograms), buprenorphine (0.3 mg) and oxymorphone (1 mg). The duration of postoperative analgesia, the presence of side effects and the neonatal outcome were also studied. Ninety healthy multiparas, at term, undergoing elective cesarean delivery using lumbar epidural anesthesia with 2% lidocaine were randomized in six equal groups to receive one of the opioids or saline. The predelivery administration of morphine, fentanyl and sufentanil significantly improved the intraoperative analgesia. Patients who received fentanyl, sufentanil, buprenorphine or oxymorphone had more somnolence than the others (p less than 0.01), but this did not interfere with the first mother-infant relationship during surgery. Patients in the buprenorphine group had more vomiting during surgery when compared with the others (p less than 0.01). Morphine provided the longest pain-free interval, followed by oxymorphone, buprenorphine, sufentanil and fentanyl. Postoperatively, the number of patients having pruritus and vomiting was significantly higher in the morphine and buprenorphine groups, respectively (p less than 0.01 versus others). No adverse neonatal effects were noted in any group.