Continuous spinal anesthesia vs. combined spinal-epidural anesthesia in emergency surgery. The combined spinal-epidural anesthesia technique does not offer an advantage of spinal anesthesia with a microcatheter

In this prospective study we investigated the efficacy of microcatheter spinal anaesthesia in comparison with a combined spinal-epidural technique in trauma patients. METHODS: After institutional approval 60 patients undergoing urgent lower-limb surgery randomly received either CSA (22 G Sprotte needle, 28 G nylon catheter) in group 1 or CSE (18 G Tuohy needle, 22 G epidural catheter and 25 G pencil-point needle) in group 2. An initial subarachnoid bolus of 2 ml of plain bupivacaine 0.5% was injected in both groups. Difficulties with the lumbar puncture or catheter insertion, the time required for performance of either technique and the onset of analgesia at T12 were documented. If analgesia did not reach T12 within 20 min, supplemental bupivacaine was injected either intrathecally or epidurally up to a maximum of 5 ml in the CSA group or 16 ml in the CSE group. RESULTS: The number of lumbar punctures (CSA: n = 1.8 +/- 1.5; CSE: n = 2.6 +/- 1.8; P = 0.05) and the incidence of technical problems (CSA: 13%, CSE: 47%; P = 0.012) was higher in the CSE group. In contrast to CSA, performance of CSE was more time consuming (CSA: 8 +/- 3 min, CSE: 15 +/- 8 min; P = 0.0003), and the total dose of local anaesthetics was higher in the CSE group (CSA: 3.2 +/- 1 ml, CSE: 9.7 +/- 5 ml; P < 0.0001). CONCLUSIONS: Because of the higher incidence of technical problems, more time was required for the performance of CSE. As a consequence, microcatheter CSA might be preferred over CSE in trauma patients.     

Combined spinal and epidural anesthesia. A review of the method

Combined spinal epidural anaesthesia (CSE) offers the fast and profound neural blockade of spinal anaesthesia, but provides the possibilities of extension of the block and post-operative pain control. On the basis of a historical review, the advantages and drawbacks of CSE are discussed, and purpose-designed needles (Eldor 1 and 2, E-SP, T-A, Braun, Mediziv) are described. The dosage problems inherent in the technique and a possible solution to the "test dose" question are described. In conclusion: CSE is a valuable alternative to established regional anaesthetic techniques. The Mediziv needle offers several advantages, but a comparative study of the different needle types is needed.     

A preliminary comparison of epidural lidocaine and xylazine during total intravenous anaesthesia in Iranian fat-tailed sheep

The effects of total intravenous anaesthesia using diazepam-ketamine (D-K) mixture in combination with epidural lidocaine or xylazine were studied in 17 healthy, Iranian fat-tailed sheep undergoing hindlimb orthopaedic surgery. All sheep were given diazepam (0.4 mg/kg) and ketamine (4 mg/kg) as induction agents. Following endotracheal intubation and administration of oxygen, the animal received lidocaine (2%, 0.2 ml/kg = 4 mg/kg) or xylazine (0.08 mg/kg, diluted in 0.9% NaCl to a volume of 0.2 ml/kg) epidurally. Anaesthesia was maintained for 174.2 +/- 7.8 minutes by intermittent injection of D-K (2.5 mg/ml and 25 mg/ml, respectively). This drug combination provided satisfactory anaesthesia for more than 2.5 hours. The quality of recovery was good. Our results demonstrate that the combination of total intravenous anaesthesia (D-K) and epidural analgesia (lidocaine or xylazine) provides a suitable technique for hindlimb orthopaedic surgery in sheep. Epidural administration of lidocaine or xylazine provided effective analgesia and significantly decreased the dose of D-K required to maintain anaesthesia. Further studies would be required to determine details of cardiopulmonary effects of D-K infusion.     

The efficacy of epinephrine test doses during spinal anesthesia in volunteers: implications for combined spinal-epidural anesthesia

Epinephrine test doses may be administered during combined spinal-epidural anesthesia to determine intravascular placement of epidural catheters. This study was designed to determine systolic blood pressure (SBP) and heart rate (HR) responses to intravenous injection of epinephrine (15 microg) during spinal anesthesia. Twelve volunteers received three spinal anesthetics (lidocaine 100 mg, tetracaine 15 mg, and bupivacaine 15 mg) in a randomized, double blind, cross-over fashion. Epinephrine was administered prior to spinal anesthesia (control), 30 min after injection of spinal anesthesia, and at regression of sensory block to T-10. SBP was measured with a radial arterial catheter and HR with an electrocardiogram. Positive responses were defined as peak increase in SBP > or = 15 mm Hg or HR > or = 20 bpm after injection of epinephrine. Compared with control, peak SBP responses decreased by a mean of 12 mm Hg during spinal anesthesia with tetracaine and bupivacaine (P < 0.05). Peak HR responses decreased by 11 bpm during all three spinal anesthetics (P < 0.05). Incidences of detection of intravenous injection by positive SBP and HR responses ranged from 50% to 100% and were not significantly affected by spinal anesthesia. Spinal anesthesia reduces hemodynamic responses to intravenous epinephrine injection but is unlikely to reduce detection by positive SBP and HR criteria.     

Comparison of lidocaine and saline for epidural top-up during combined spinal-epidural anesthesia in volunteers

This study was designed to determine the efficacy of saline as an epidural top-up to prolong spinal anesthesia during combined spinal-epidural anesthesia (CSEA). Eight volunteers received three separate CSEAs with intrathecal lidocaine (50 mg). After two-segment regression, each subject received either a saline (10 mL), lidocaine 1.5% (10 mL), or control sham (0.5 mL saline) epidural injection in a randomized, double-blind, triple cross-over fashion. Sensory block was assessed by pinprick and tolerance to transcutaneous electrical stimulation (TES) equivalent to surgical stimulation at the knee and ankle. Motor strength was assessed with iso-metric force dynamometry. Data were analyzed with a repeated measures analysis of variance and a paired t-test. Sensory block to pinprick was prolonged in the thoracolumbar dermatomes only by lidocaine (P < 0.05). Neither lidocaine nor saline prolonged the duration of tolerance to TES at the tested sites. Instead, saline decreased the duration of tolerance to TES by 20 and 24 min at the knee and ankle (P < 0.05). Recovery from motor block at the quadriceps was prolonged by an epidural injection of lidocaine (P < 0.05). We conclude that when 10 mL of epidural saline is administered after two-segment regression, it is an ineffective top-up and may decrease the duration of spinal anesthesia during CSEA.     

Peridural anesthesia versus subarachnoid anesthesia in cesarean section. Prospective clinical study

OBJECTIVE: To compare technical and clinical differences between epidural and spinal anesthesia for cesarean section. STUDY DESIGN: Randomized prospective trial. PATIENTS AND METHODS: 64 pregnant women at term scheduled for elective cesarean section. Two groups were randomized: A) PD Group (n = 32): continuous epidural anesthesia by administration of bupivacaine 0.5% plus epinephrine 1/400,000 via an epidural catheter. Epidural morphine 3 mg was administered at the end of surgery. B) SP Group (n = 32): "single shot" spinal anesthesia by intrathecal administration of hyperbaric 1% bupivacaine 1-1.4 ml plus morphine 0.2 mg. The pin prick block level reached T2-T6 at incision time. DATA COLLECTION: 1) Time from the beginning of anesthesia to surgical incision. 2) Hypotension episodes. 3) Ephedrine consumption. 4) Intraoperative discomfort at delivery, traction and uterine manipulation, peritoneal toilette. 5) Nausea and vomiting. 6) Apgar score. 7) Postoperative headache. RESULTS: Women in the SP group had more hypotensive episodes (81% vs 53%: p < 0.05) and more ephedrine consumption with a large individual variability (29.12 mg +/- 20.4 vs 12.83 +/- 13.8: p < 0.01) when compared to PD group, without any difference in the Apgar score. The SP group required less time consumption (10.5 min. +/- 6.7 vs 35.9 min. +/- 17.3: p < 0.01) and had less intraoperative discomfort with less analgesic and/or sedative drugs consumption (9.7% vs 29%: p < 0.05) and less vomiting (3% vs 22.5%: p < 0.05). No postoperative headache was noticed in both groups. CONCLUSIONS: With the described pharmacological and technical approach, spinal anesthesia is more suitable than continuous epidural technique for cesarean section, unless contraindicated.     

Continuous thoracic epidural blockade in combination with general anesthesia with nitrous oxide, oxygen, and sevoflurane in two patients with myasthenia gravis

Continuous thoracic epidural anesthesia (T4/5) using 4-5 ml.h-1 of 1.5% lidocaine with 1:200,000 epinephrine and inhaled anesthesia using nitrous oxide, oxygen and sevoflurane were performed in two patients, (40 and 22 yr-old females) with myasthenia gravis. This combined anesthetic technique provided muscle relaxation for endotracheal intubation and optimal operating conditions, including muscle relaxation and stability of hemodynamics during transsternal thymectomy. Further, continuous epidural anesthesia using 4 ml.h-1 of 0.25% bupivacaine provided postoperative pain relief without other analgesics and stable postoperative respiratory conditions. In conclusion, we confirm the benefits of this technique which provides not only safe and stable conditions during the surgery, but also an improved comfort for patients in the postoperative period following transsternal thymectomy for myasthenia gravis.     

Pharmacology of local anesthetics and clinical aspects of segmental blocking. II. Spinal anesthesia

Clinical picture of development of segmental blocking after subarachnoidal injection of hyperbaric solutions of 0.75% bupivacaine, 5% ultracaine, and isobaric 0.5% bupivacaine is studied. A total of 152 patients operated on the lower part of the body and the lower limbs were examined under conditions of single, prolonged subarachnoidal, and combined spinal epidural anesthesia. Ultracaine and bupivacaine in different concentrations with different barism provided anesthesia equivalent by the efficacy, depth, and dissemination of sensory block. Segmental blocking with 5% ultracaine was characterized by the shortest latent period (3.14 +/- 0.16 min, p < 0.05) but was no shorter (124.1 +/- 3.37 min) than operative analgesia with 0.75% hyperbaric bupivacaine (120.0 +/- 5.10 min). Isobaric bupivacaine provided the longest effective analgesia (215.0 +/- 45.0 min, p < 0.05). Microcatheter technique improved the safety and control of subarachnoidal anesthesia in comparison with a single injection, and combined spinal epidural anesthesia shortened the latent period of segmental blocking and ensured intraoperative anesthesia and postoperative analgesia at the expense of the epidural component.     

Ropivacaine 7.5 mg/ml for elective caesarean section. A clinical and pharmacokinetic comparison of 150 mg and 187.5 mg

BACKGROUND: The new, long-acting local anaesthetic ropivacaine has shown less systemic toxicity than bupivacaine and a concentration of 7.5 mg/ml can therefore be used for epidural anaesthesia in Caesarean section. The present pilot study was undertaken to find indications for an optimal dosage by comparing the clinical effects, quality of anaesthesia and pharmacokinetics of ropivacaine 150 mg (lower dose = LD) vs 187.5 mg (higher dose = HD) for women undergoing elective Caesarean section under epidural anaesthesia. METHODS: Sixteen full-term women scheduled for elective Caesarean section in two equal-sized consecutive groups received 20 or 25 ml ropivacaine epidurally in this non-randomised, open study. Study parameters included sensory and motor blockade, circulatory response, intraoperative pain and discomfort, neonatal evaluation and pharmacokinetic determinations. RESULTS: Block height varied between T5 and T2 in the LD group, whereas the HD group produced 4 unnecessarily high blocks (C8 in 3 women and C7 in 1 woman). Surgical anaesthesia was excellent in both groups. Circulatory stability was pronounced in the LD group (no ephedrine given), while 4 women required ephedrine in the HD group. Neonatal outcome as judged by Apgar scores; umbilical blood gas determinations and NACS scores were excellent in both groups. The plasma concentration-time profiles indicated linearity in the concentration range studied, with similar clearance values to those reported previously. Placental drug equilibrium was rapid; however, the foetal drug exposure depended on intrauterine exposure time. CONCLUSIONS: 20-25 ml ropivacaine 7.5 mg/ml produced very satisfactory conditions for elective Caesarean section under epidural anaesthesia. In this small population, 150 mg ropivacaine seemed optimal, while 187.5 mg produced unnecessarily extended block height in 50% of the women.     

Prospective study of the incidence of transient radicular irritation in patients undergoing spinal anesthesia

BACKGROUND: There is considerable controversy regarding the role of subarachnoid 5% hyperbaric lidocaine in the syndrome transient radicular irritation (TRI). This randomized, double-blinded, prospective study was designed to determine the incidence of TRI and identify factors possibly contributing to its development. METHODS: One hundred fifty-nine ASA physical status 1 or 2 patients undergoing outpatient knee arthroscopy or unilateral inguinal hernia repair were prospectively randomized to receive spinal anesthesia with 5% hyperbaric lidocaine with epinephrine (60 mg with 0.2 mg epinephrine for arthroscopy or 75 mg with 0.2 mg epinephrine for hernia repair), 2% isobaric lidocaine without epinephrine (60 mg for arthroscopy or 75 mg for hernia repair), or 0.75% hyperbaric bupivacaine without epinephrine (7.5 mg for arthroscopy or 9.0 mg for hernia repair) in a double-blinded fashion. On the 3rd postoperative day, patients were contacted by a blinded investigator and questioned regarding the incidence of postoperative complications including TRI, defined as back pain with radiation down one or both buttocks or legs occurring within 24 h after surgery. Postoperatively, time from injection to block resolution, ambulation, voiding, and ready for discharge were recorded by a postanesthesia care unit nurse blinded to the group assignment. RESULTS: The incidence of TRI was greater in patients receiving lidocaine than in those receiving bupivacaine (16% vs. 0%; P = 0.003). There was no difference in the incidence of TRI between the patients receiving 5% hyperbaric lidocaine with epinephrine and those receiving 2% isobaric lidocaine without epinephrine (16% vs. 16%; P = 0.98). The incidence of TRI was greater in patients undergoing arthroscopy than in those undergoing hernia repair (13% vs. 5%; P = 0.04). There was no difference in discharge times in patients receiving bupivacaine versus those receiving hyperbaric lidocaine with epinephrine (292 vs. 322 min; P = 0.61). CONCLUSIONS: The incidence of TRI is greater with lidocaine than bupivacaine, decreasing the lidocaine concentration to 2% does not prevent TRI, and surgical position may be an important contributing factor. Discharge times at our institution are not different when equipotent doses of 0.75% hyperbaric bupivacaine or 5% hyperbaric lidocaine with 0.2 mg epinephrine are used in ambulatory patients undergoing spinal anesthesia.     

Concept of stress ulcer prevention. Is re-thinking necessary?

BACKGROUND: Continuous spinal anesthesia (CSA) has been considered to be better in temporal and dose flexibility, as well as hemodynamic stability than single dose spinal anesthesia. However, the failure of spinal anesthesia is not a rare experience for anesthesiologists. Here we present our experience in solving the problem and discuss the possible causes for the failure. METHODS: 236 cases were studied retrospectively from January to December in 1996. All were over 65 years old, ASA III, scheduled for transurethral procedures or orthopedic operation. CSA was performed with 0.2% bupivacaine. Failed CSA was confirmed by positive pin-prick test at T10 dermatome(umbilicus) 30 minutes after 20 mg bupivacaine was injected. For failed cases, 5 mL 1% lidocaine was injected intrathecally for rescue. The failure rate, sensory and motor blockade, success rate by changing to lidocaine and its dosage were recorded. RESULTS: Eleven of 236 cases (4.7%) were considered spinal failure since the initial 20 mg bupivacaine could not provide adequate T10 anesthesia in 30 minutes. Addition of 5 mL 1% lidocaine produced a profound sensory and motor blockade in 9 cases, while further lidocaine injection was required in two cases. The success rate by rescuing lidocaine was 100% with an average lidocaine consumption by 52.5 +/- 4.5 mg. DISCUSSION: Factors contributed to failure spinal anesthesia including failure of technique, errors of judgment, maldistribution and failure of local anesthetic itself. However, we thought that change of pH value of local anesthetic in CSF may play a great part in these failed CSAs. Despite the reasons for failure, we demonstrate that failure of continuous spinal anesthesia by 0.2% bupivacaine can be readily resolved by 1% lidocaine.     

Intrathecal fentanyl with small-dose dilute bupivacaine: better anesthesia without prolonging recovery

Recent concern regarding lidocaine neurotoxicity has prompted efforts to find alternatives to lidocaine spinal anesthesia. Small-dose dilute bupivacaine spinal anesthesia yields a comparably rapid recovery profile but may provide insufficient anesthesia. By exploiting the synergism between intrathecal opioids and local anesthetics, it may be possible to augment the spinal anesthesia without prolonging recovery. Fifty patients undergoing ambulatory surgical arthroscopy were randomized into two groups receiving spinal anesthesia with 3 ml 0.17% bupivacaine in 2.66% dextrose without (Group I) or with (Group II) the addition of 10 microg fentanyl. Median block levels reached T7 and T8, respectively (P = not significant [NS]). Mean times to two-segment regression, S2 regression, time out of bed, time to urination, and time to discharge were 53 vs 67 min (P < 0.01), 120 vs 146 min (P < 0.05), 146 vs 163 min (P = NS), 169 vs 177 min (P = NS), and 187 vs 195 min (P = NS) respectively. Motor blockade was similar between groups, but sensory blockade was significantly more intense in Group II (P < 0.01). Six of 25 blocks failed in Group I, whereas none failed in Group II. The addition of 10 microg fentanyl to spinal anesthesia with dilute small-dose bupivacaine intensifies and increases the duration of sensory blockade without increasing the intensity of motor blockade or prolonging recovery to micturition or street fitness. IMPLICATIONS: Concerns about the neurotoxicity of lidocaine have prompted efforts to find alternatives to lidocaine spinal anesthesia. We studied 50 patients undergoing ambulatory surgical arthroscopy and found that although small-dose bupivacaine alone is inadequate for this procedure, the addition of fentanyl makes it reliable.     

Postoperative patient-controlled epidural analgesia with opioid bupivacaine mixtures

PURPOSE: To determine the efficacy and safety of patient-controlled epidural analgesia of morphine or fentanyl in combination with bupivacaine for postoperative pain relief. METHODS: Forty ASA I-II patients scheduled for major abdominal surgery were studied. After insertion of a lumbar epidural catheter, patients were given a non-opioid general anaesthetic. After surgery patients complaining of pain, received a loading dose of 2 mg morphine (Group I) or 50 micrograms fentanyl (Group II). For continuing pain, 1 mg morphine in 4 ml bupivacaine 0.125% (0.25 mg.ml-1 morphine and 1 mg.ml-1 bupivacaine, Group I) or 20 micrograms fentanyl in 4 ml bupivacaine 0.125% (5 micrograms.ml-1 fentanyl and 1 mg.ml-1 bupivacaine Group II) were administered. Blood pressure, heart rate, respiratory rate and SpO2 were monitored. Assessments of pain (VAS), nausea-vomiting, motor block, pruritus and sedation were recorded for 24 hr. RESULTS: No difference in pain or sedation was observed between groups. The 24 hr postoperative opioid consumption was 15.50 +/- 7.53 mg morphine and 555.10 +/- 183.85 micrograms fentanyl. Total bupivacaine 0.125% consumption was 58.00 +/- 30.14 ml in Group I and 101.05 +/- 36.77 ml in Group II. One patient in Group II complained of motor weakness in one leg. The incidence of nausea (Group I 45%, Group II 10% P < 0.05) and pruritus (Group I 30%, Group II 5% P < 0.05) was less in patients receiving fentanyl. CONCLUSION: Both methods were effective in the prevention of pain but, because of fewer side effects, fentanyl may be preferable to morphine.     

Long-term epidural analgesia for pregnancy-induced intercostal neuralgia

Intercostal neuralgia is one of many possible neurological disorders associated with pregnancy. A woman presented in the 34th week of her 4th pregnancy with progressing right-sided pain and hypoesthesia in the ribs, right upper quadrant of the abdomen, and mid-thoracic area of her back. With a clinical diagnosis of pregnancy-related intercostal neuralgia, we inserted an epidural catheter at T8 for ambulatory pain management. A continuous infusion of bupivacaine was titrated by concentration and rate until adequate analgesia was obtained. The final effective dose consisted of 0.125% bupivacaine at 6 ml/h with a patient-controlled bolus dose of 2 ml every 30 min as needed (4-6 boluses per 24-h period). This allowed the patient to continue to work full-time and perform daily activities with minimal discomfort. The epidural infusion was continued until the patient went into spontaneous labor 28 days after the initial clinical visit. A full-term infant was delivered without incident. No major complications occurred such as local anesthetic toxicity, hypotension, motor weakness, or infection. Minor complications included disconnection of the catheter cap and accidental dislodgment, which required placement of a second epidural catheter. For this patient, an appropriately placed chronic epidural catheter and a titrated continuous infusion of bupivacaine provided adequate and safe analgesia for pregnancy-associated intercostal neuralgia.     

Caudal clonidine and bupivacaine for combined epidural and general anaesthesia in children

BACKGROUND: Clonidine produces analgesia by actions on alpha 2-adrenoceptors and enhances both sensory and motor blockade from epidural injection of local anaesthetics. Low-dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperative effects of high-dose caudal clonidine when added to low concentration of bupivacaine for combined epidural and general anaesthesia in children. METHODS: After induction of general anaesthesia caudal block was performed either with 1 ml.kg-1 bupivacaine 0.175% with the addition of clonidine 5 micrograms.kg-1 (n = 20), or with 1 ml.kg-1 bupivacaine 0.175% (n = 20). The intraoperative anaesthetic requirements, the perioperative haemodynamic effects, respiratory rate, sedation score, postoperative pain scores and side effects were assessed by a blinded observer. A patient-controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed using Smiley's pain analogue scale. RESULTS: Intraoperative haemodynamic responses did not differ between the groups. However, during emergence from general anaesthesia children in the clonidine group had significantly lower heart rates and blood pressure compared to children in the control group. In addition, heart rates and blood pressures were also lower in the clonidine group in the early postoperative period (P < 0.05). Postoperative analgesia was significantly better in the clonidine group as evidenced by the total number of requests (3 vs 12, P < 0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P < 0.05) administered. The duration of the caudal analgesia was significantly longer in the clonidine group (20.9 +/- 7.4 h vs 14.4 +/- 10.9 h, P < 0.05). CONCLUSION: Our results suggest that caudal clonidine 5 micrograms.kg-1 enhances and prolongs caudal blockade with bupivacaine (1.175% in children. It also blocks sympathoadrenergic responses during emergence from anaesthesia. Sedation and cardiovascular effects are observed up to 3 h into the postoperative period.     

Evaluation of the effectiveness of anecaine in central segmental blockades in orthopedic-traumatologic interventions

Efficacy of anecaine (A) (bupivacaine, Pliva) and marcaine (M) (bupivacaine, Astra) in central neuroaxial block combined with sedation is compared. In the group with epidural block (n = 167, ASA I-III), 102 patients were given anecaine and 65 marcaine in equivalent doses. In the group with spinal block (n = 82, ASA I-III), anecaine was administered to 52 and marcaine to 30 patients. In the epidural block group a catheter was placed at L2-3 or L3-4 with cranial direction. A test dose of bupivacaine (20 mg) was followed after 5-7 min by the main dose of 2 mg.kg-20 mg. Propofol was given for partial suppression of consciousness at a continuous infusion rate 1.6 mg.kg.hr. In spinal block group, bolus dose of bupivacaine (10-20 mg) was injected through the subarachnoidal approach at L2-3 or L3-4. Diazepam (0.1 mg.kg.hr) was used for sedation. Block onset, duration of sensor and motor block, and of effective analgesia were evaluated in all groups. Hemodynamics and respiratory function were monitored. Moderate hypotension (16-17% decline from basic values) was observed in all patients irrespective of bupivacaine brand. In a comparative non-randomized study anecaine showed a faster onset of block and longer duration of clinical effect than marcaine in epidural and spinal anesthesia for orthopedic surgery on the lower limbs.     

Risks and recommendations in Bechterew disease. Paraparesis after epidural anesthesia

We describe a case of paraparesis caused by an epidural haematoma in a 74-year-old man with advanced ankylosing spondylitis who received combined epidural and general anaesthesia for graft repair of an aneurysm of the abdominal aorta. Before the induction of general anaesthesia, an epidural catheter was inserted at the level of thoracic vertebrae 10-11 without difficulty or signs of bleeding. Total analgesia and paralysis of the legs in the early postoperative period raised suspicions of the presence of an epidural haematoma, which was confirmed by magnetic resonance tomography. Aspiration of the epidural catheter yielded 13 ml of blood. Despite early surgical decompression after transfer to a regional hospital, the patient remains paraparetic. We wish to highlight the risks of epidural anaesthesia in cases of ankylosing spondylitis, and to stress the need of routine control of motor function after epidural anaesthesia.     

Effect of thoracic epidural anaesthesia on ventilation-perfusion distribution and intrathoracic blood volume before and after induction of general anaesthesia

BACKGROUND: Gas exchange is impaired during general anaesthesia due to development of shunt and ventilation-perfusion mismatching. Thoracic epidural anaesthesia (TEA) may affect the mechanics of the respiratory system, intrathoracic blood volume and possibly ventilation-perfusion (VA/Q) distribution during general anaesthesia. METHODS: VA/Q relationships were analyzed in 24 patients undergoing major abdominal surgery. Intrapulmonary shunt (Qs/QT), perfusion of "low" VA/Q areas, ventilation of "high" VA/Q regions, dead space ventilation and mean distribution of ventilation and perfusion were calculated from the retention/excretion data of six inert gases. Intrathoracic blood volume (ITBV) and pulmonary blood volume (PBV) were determined with a double indicator technique. Recordings were made before and after administration of 8.5 +/- 1.5 ml bupivacaine 0.5% (n = 12) or 8.3 +/- 1.8 ml placebo (n = 12) into a thoracic epidural catheter and after induction of general anaesthesia. RESULTS: Before TEA, Qs/QT was normal in the bupivacaine group (2 +/- 2%) and the placebo group (2 +/- 3%). TEA covering the dermatomal segments T 12 to T 4 had no effect on VA/Q relationships, ITBV and PBV. After induction of general anaesthesia Qs/QT increased to 8 +/- 4% (bupivacaine group, P < 0.05 and to 7 +/- 2% (placebo group, P < 0.05). ITBV and PBV decreased significantly to the same extent in the bupivacaine group and the placebo group. CONCLUSIONS: TEA has no effect on VA/Q distribution, gas exchange and intrathoracic blood volume in the awake state and does not influence development of Qs/QT and VA/Q inequality after induction of general anaesthesia.     

The influence of epidural administration of fentanyl infusion on gastric emptying in labour

The effect of epidural infusions containing fentanyl on maternal gastric emptying in labour was examined using the rate of paracetamol absorption. Women were randomly allocated to receive one of two epidural infusions, bupivacaine 0.125% alone or bupivacaine 0.0625% with fentanyl 2.5 micrograms.ml-1 at a rate of 10-12 ml.h-1. Paracetamol 1.5 g was given orally to women after either 30 ml of the infusion solution had been given (mean time 2.5 h, study A) or 40-50 ml (mean time 4.5 h. study B). Six venous blood samples were taken over the next 90 min for measurement of plasma paracetamol concentration. There were no significant differences in maximum plasma paracetamol concentration, time to maximum paracetamol concentration and area under the concentration-time curve between the two groups for study A. In study B the time to maximum plasma paracetamol concentration was significantly delayed in women receiving > 100 micrograms fentanyl compared with controls (p < 0.05). We conclude that the dose of fentanyl that may delay gastric emptying when given by epidural infusion is greater than 100 micrograms.     

Two cases of cauda equina syndrome following spinal-epidural anesthesia

BACKGROUND AND OBJECTIVES: Cauda equina syndrome (CES) is a well-known complication of spinal and epidural anesthesia. Previous reports have implicated lidocaine, chloroprocaine, and procaine in its etiology, but not bupivacaine. METHODS: A 63-year-old man underwent transurethral resection of the prostrate for which he received bupivacaine with glucose intrathecally. Postoperative, he had difficulty in urination and defecation, and magnetic resonance imaging revealed spinal stenosis at the L1-L2 level. The second patient was a 70-year-old woman who underwent hip replacement surgery using a combined spinal-epidural technique. Postoperative, after 42 hours, when the epidural infusion of bupivacaine was stopped, the patient had difficulty in urination and defecation. No anatomical abnormality was found on magnetic resonance imaging. RESULTS: The two patients developed cauda equina syndrome following bupivacaine with glucose injected spinally, and bupivacaine without glucose injected in a combined spinal-epidural technique. CONCLUSIONS: This case report describes two cases of CES following the use of bupivacaine. The first patient had spinal stenosis which could explain this complication; however the explanation for CES in the second patient is uncertain and consequently speculative. We have discussed the possible contributing factors but believe that the etiology of CES in the second patient remains unknown.