Hyperbaric Tetracaine Research Articles

Hemodynamic changes during spinal anesthesia in premature infants with congenital heart disease undergoing inguinal hernia correction

There are conflicting reports on the effects of spinal anesthesia (SA) on hemodynamics. Data on the hemodynamic effects of SA in infants with congenital heart disease (CHD) are limited. We reviewed our experience with 44 unsupplemented SA with 1 mg·kg(-1) of either hyperbaric tetracaine or bupivacaine in premature and former premature infants with noncyanotic CHD. Hemodynamics and oxyhemoglobin saturation (SpO(2)) were assessed. Neither preoperative fluid boluses nor atropine was administered to any of the infants. There was no significant change in systolic, diastolic, or mean blood pressures from pre-SA induction compared with end of surgery. Heart rate showed a small but systematic decline (mean change of 10 beats per minute, P < 0.01) but was within the normative range values for age. There was a small, but clinically insignificant increase in SpO(2) across the time course. Intraoperatively, two infants developed transient apneic spells. No infant developed postoperative apnea, oxygen desaturation, or bradycardia. The data suggest that SA with 1 mg·kg(-1) of either hyperbaric tetracaine or bupivacaine can be used safely as the sole anesthetic for inguinal hernia repair in infants with noncyanotic CHD even when fluid restricted and apparently causes minimal respiratory complications in these infants.

Introduction of a New Concept of Pain Management during Labor and a Novel Technique for Pain Free Labor

Traditional labor epidural techniques have not been proven to be sufficient to cover the second stage of labor. We have developed a new concept of pain management during labor and a new technique that provides sufficient analgesia for second stage of labor. Combined Spinal Epidural with long lasting saddle block (with hyperbaric tetracaine) was used. Potentially pain free labor could be achieved by using this method. Utilizing hyperbaric Tetracaine intrathecally may provide a long lasting sensory sacral blockade. Primary outcome measure was absence of pain during pushing (2nd stage of labor). Patients received additional comfort during 1st stage of labor. Sample size included all patients that requested labor epidurals since 12/22/11 when this new technique was introduced.

Cauda equina syndrome after spinal anesthesia: A case report.

A 72-year-old man undergoing emergency arthroscopic irrigation and debridement of the left knee joint due to pyogenic arthritis developed cauda equina syndrome after spinal anesthesia with 0.5% hyperbaric tetracaine mixed with epinephrine. Epinephrine was added to local anesthetic to prolong the duration and to increase the quality of spinal anesthesia. There was no paresthesia on needle placement. We injected anesthetics twice because the first subarachnoid injection failed. The patient experienced impaired sensation in the perineal region and alterations in bowel and urinary habits. Magnetic resonance imaging revealed spondylolisthesis and disc protrusion (L4-5), with spinal stenosis (L5-S1), but did not show suspicious lesions such as hematoma and abscess. We suggest the causative factors are temporary neural compression due to his spinal diseases and spinal cord ischemia due to decreased spinal blood flow because of epinephrine. We also cannot rule out the tetracaine neurotoxicity.

Propofol infusion for sedation during spinal anesthesia

The dose and time course of propofol infusion required to induce rapid sedation without oversedation during spinal anesthesia were investigated. Forty patients scheduled for spinal and epidural anesthesia were studied. After premedication with intramuscular midazolam 0.04 mg.kg(-1), an epidural catheter was inserted, followed by spinal anersthesia at L4-L5 with 0.5% hyperbaric tetracaine with epinephrine. The infusion of propofol was started with 10 mg.kg(-1).h(-1) and was decreased to 5 mg.kg(-1).h(-1) at spontaneous eye closure. According to the increase or decrease of the sedation level, the infusion does was decreased or increased to half or twice the initial dose, respectively, to keep the Observer's Assessment of Alertness Sedation (OAAS) score at 3 or 4. Eye closure was observed at 1.0 +/- 0.4 min after the start of insusion. The maintenance insusion dose to keep the OAAS score at 3 or 4 was about 2.5 mg.kg(-1).h(-1). Propofol infusion, starting with 10 mg.kg(-1).h(-1), decreasing to 5 mg.kg(-1).h(-1) after 1 minute, and then decreasing to 2.5 mg.kg(-1).h(-1) after another min induced rapid onset of sedation and kept the OAAS score at 3 or 4 during spinal anesthesia.

Treatment of Pain and Stress in the Neonate

After completing this article, readers should be able to: 1. Describe the pain assessment tools used for preterm and term neonates. 2. List painful procedures in the neonatal intensive care unit (NICU). 3. Describe nonpharmacologic interventions for alleviating neonatal pain. 4. Describe pharmacologic methods used for neonatal analgesia. 5. Delineate the adverse effects of the common forms of pain relief. Neonates are sensitive to pain and vulnerable to both its short- and long-term effects. However, there is a lack of consistency in both attitudes and practices among NICU staff with regard to pain assessment and management in neonates. Recognition of the clinical importance of neonatal pain and stress has been delayed and hampered by the lack of awareness that newborns are capable of experiencing pain, insufficient knowledge about the developing nervous system, difficulty in assessing neonatal pain, lack of evidence for the safety and efficacy of different modalities available for the treatment of pain, and fears about adverse effects associated with analgesic use. Neonatal pain has been of minimal concern until the last 25 years. For example, at one time, neonates were given paralytic drugs without anesthesia for major surgical procedures because physicians believed that neonates were incapable of interpreting or remembering pain. Further, there was no understanding of the consequences of untreated pain. Newer technologies to sustain life have exposed neonates to multiple invasive procedures and prolonged hospital stays that are associated with acute and chronic pain and stress. In 2001, an international evidence-based group for neonatal pain developed guidelines for the assessment, prevention, and treatment of neonatal pain in an effort to standardize practices for physicians and health care facilities. Within the consensus statement, the group defined general principles to prevent and treat pain and listed the most commonly performed diagnostic, therapeutic, and surgical procedures in the NICU. The guidelines also indicated the …

硬膜外麻酔併用腰椎麻酔下前立腺全摘除術の有用性についての検討

To evaluate the efficacy of combined lumbar spinal and epidural (CLSE) anesthesia in retropubic radical prostatectomy. Twenty consecutive patients who underwent radical retropubic prostatectomy by a single surgeon (H.K.) under CLSE anesthesia from July of 2003 to February of 2004 were selected as subjects. They were compared with 20 consecutive patients who underwent radical retropubic prostatectomy performed by the same surgeon under combined general and epidural (CGE) anesthesia from April to December of 2002. Both periods were carefully selected to exclude radical prostatectomies with intraoperative complications to evaluate genuine effects of anesthesia. For lumbar spinal anesthesia, 0.5% hyperbaric bupivacaine hydrochloride or 0.5% hyperbaric tetracaine hydrochloride (dissolved in a 10% glucose solution) was used. An epidural tube was inserted for both lumbar spinal anesthesia and general anesthesia mainly for the purpose of controlling a pain after operation. Intraoperative blood loss was significantly less in the CLSE anesthesia group compared with CGE anesthesia group (p = 0.024). Postoperative water drinking was started at 0.4 days (average) for CLSE anesthesia and at 1.1 days (average) for CGE anesthesia (p < 0.0001). Postoperative diet was begun at 0.7 days (average) for CLSE anesthesia and at 1.5 days (average) for CGE anesthesia (p < 0.0001). Compared with the CLSE anesthesia group, the mean of the highest intraoperative mean blood pressure was significantly higher in the CGE anesthesia group (p = 0.002). Intraoperative blood loss was less, intraoperative change in blood pressure was less and recovery of postoperative intestinal peristalsis was earlier in patients who underwent prostatectomy under CLSE anesthesia than in patients who underwent prostatectomy under CGE anesthesia. We believe that prostatectomy under CLSE anesthesia is more advantageous than prostatectomy under CGE anesthesia.

Dose-finding study of intravenous midazolam for sedation and amnesia during spinal anesthesia in patients premedicated with intramuscular midazolam

We investigated the effective and safe dose of intravenous midazolam for sedation and amnesia during spinal anesthesia in patients premedicated with intramuscular midazolam. One hundred and eighty patients aged 20-50 years scheduled for spinal anesthesia received midazolam 0.06 mg.kg(-1) and atropine 0.01 mg.kg(-1) intramuscularly 15 min before entering the operating room. Spinal anesthesia was performed with 0.5% hyperbaric tetracaine. Five minutes after starting surgery, midazolam 0 (control group), 0.01, 0.02, 0.03, 0.04, or 0.05 mg.kg(-1) was intravenously administered (30 patients each). Blood pressure, heart rate, respiratory rate, percutaneous oxygen saturation (S(p)(O)(2)), verbal response, eyelash reflex, and involuntary body movement were measured every 5 min for 30 min. Memory during surgery was also investigated. The number of the patients with loss of verbal response, with loss of eyelash reflex, and with no memory during surgery were significantly larger in the groups receiving midazolam >or=0.03 mg.kg(-1), >or=0.04 mg.kg(-1), and >or=0.02 mg.kg(-1), respectively. The decrease in blood pressure or increase in respiratory rate with decrease in S(p)(O)(2) was significantly larger in the groups receiving midazolam >or=0.03 mg.kg(-1) or 0.05 mg.kg(-1), respectively. For sedation and amnesia of the patients aged 20-50 years in spinal anesthesia with about 1 h duration receiving intramuscular midazolam 0.06 mg.kg(-1) as a premedication, intravenous midazolam 0.02 mg.kg(-1) might be effective and safe.

Spinal Anesthesia with 0.2% Hypobaric Tetracaine for Total Hip Replacement

Background: Using hypobaric local anesthetics, patients undergoing total hip replacement surgery (THR) can be anesthetized in the lateral decubitus position with operative side up, and do not need to be repositioned for operation. This can save preparation time and inadvertent change of anesthetic level due to position change. Number of studies have exmined the use of hypobaric local anesthetics for THR, but the main focus of the studies was to compare the effect of various drugs or baricities, rather than adequate dosages. Therefore, we aimed to determine adequate dosages of hypobaric tetracaine for THR. Methods: Sixty patients were randomly allocated into three groups. Spinal anesthesia was performed in the lateral decubitus position with the operated side uppermost using 0.2% tetracaine diluted with distilled water, 10, 12, or 14 mg was administered into the subarachnoid space. Results: Time to T10 block, the lebel of maximal sensory and motor block, and the incidence of hypotension were no different in the three dosage groups. The number of patints who showed adequate anesthesia (mor than T10 and modified Bromage scale 2) were no different. Duration of sensory block and the time to complete motor recovery increased with dosage. The number of patients with less than a 2 hour sensory block was higher in the 10 mg group (50%) than in the two other groups (10% in 12 mg, 0% in 14 mg). Conclusions: 10 mg of hyperbaric tetracaine was not enough, and 14 mg adequate for a hip surgery of 2 hour duration. The two doses were similar in terms of the sensory and motor block level and the incidence of hypotension.

Haemodynamic changes during high spinal anaesthesia in children having open heart surgery

This prospective series examined the haemodynamic effects of high spinal anaesthesia in combination with light general anaesthesia in infants and children undergoing open heart surgery who were candidates for immediate or early postoperative extubation. After midazolam premedication and sevoflurane inhalation induction, 30 patients, aged 7 months to 13 years, who were undergoing open heart surgery, received spinal anaesthetics with 0.5% tetracaine D10 mixed with morphine. The spinal blocks were placed at the L2,3 or L3,4 interspace with cephalad spread being promoted by positioning the patient in 30 degrees of Trendelenburg for a minimum of 10 min. Maintenance of anaesthesia was with isoflurane 0.2-0.5% in 70% nitrous oxide to maintain heart rate and blood pressure within 20% of postinduction baseline values. Haemodynamic values were recorded at predetermined timed intervals and intraoperative events up to and including aortic cannulation. For analysis of the data, patients were divided into four age groups (< 1 years, 1-3 years, 4-6 years and > 7 years). Haemodynamic stability was demonstrated in all four age groups. Statistically significant slowing of the heart rate did occur in the groups older than 1 year at 25 min, although clinically significant bradycardia requiring treatment never occurred. Hypotension did occur during specific surgical manipulations but recovered spontaneously. Atropine, fluid boluses and vasopressors were never used. At the conclusion of surgery, all patients met extubation criteria and could move all four extremities. High spinal anaesthesia with hyperbaric tetracaine and morphine in combination with light general anaesthesia is well tolerated haemodynamically by the paediatric population studied.

The effect of baricity of intrathecal morphine in children receiving tetracaine spinal anaesthesia for cardiac surgery: a preliminary report

This prospective, randomized study examined the effect of baricity of intrathecal preservative-free morphine on the duration of postoperative analgesia and incidence of side-effects in infants and children receiving high spinal anaesthesia with hyperbaric tetracaine in combination with a light general anaesthetic. Fourteen infants and children, aged 7-91 months, undergoing repair of either uncomplicated atrial or ventricular septal defects, were randomized to receive either 10 microg x kg(-1) of intrathecal morphine in combination with 0.5% tetracaine D10 (hyperbaric morphine group) or intrathecal morphine mixed with saline and injected sequentially after the administration of 0.5% tetracaine D10 (hypobaric morphine group). After spinal injection, patients were positioned in 30 degrees of Trendelenburg for a minimum of 10 min. Postoperatively, patients were monitored for a minimum of 12 h. Pain scores and the incidence and severity of side-effects were recorded every 1 h. All patients were extubated at the conclusion of surgery without any incidence of respiratory depression. There was a decreased incidence of vomiting in the hypobaric morphine group and no significant difference in the duration of analgesia. When intrathecal morphine is administered in conjunction with a hyperbaric tetracaine spinal to paediatric cardiac patients in the head down position, sequential administration of the hypobaric solution may mitigate side-effects.

Spinal anesthesia in 62 premature, former-premature or young infants--technical aspects and pitfalls.

To highlight technical aspects and pitfalls of spinal anesthesia (SA) in infants. The medical history and perioperative course of all infants who underwent SA over a 28-month period were collected (retrospectively in the first 20). Sixty-two infants underwent surgery under SA. Fifty-five were premature and former-premature, postconceptional age 43.3 +/- 5.0 weeks, weight 3261 +/- 1243 g. Of these, 21 had co-existing disease: cerebral (six), cardiac (nine), pulmonary (11) and urological (six). Hyperbaric tetracaine or bupivacaine 1 mg x kg(-1) with adrenaline was administered. Four infants (three premature) required N(2)O supplementation and three needed general anesthesia. The supplementation rate was similar or lower than in previous studies. Postoperatively, all seven were shown to have lower limb motor and sensory blockade. Complications in premature patients included intraoperative hypoxemia (two), apnea (two) and bradycardia (one). Postoperative complications included bradycardia (three), hypoxemia (one) and apnea and hypoxemia (one). The postoperative complication rate was similar to previous studies. Successful SA in infants depends on close attention to preoperative assessment, appropriate patient positioning during and after lumbar puncture, drug dosing and intra- and postoperative cardiorespiratory monitoring. A relatively high dose of hyperbaric solution of tetracaine or bupivacaine with adrenaline should be administered.

Spinal Anesthesia with Tetracaine in 7.5% or 0.75% Glucose in Adolescents and Adults

To examine whether adolescents and adults might develop different anesthetic distribution and hemodynamic consequences after spinal injection of 0.5% tetracaine in 7.5% or 0.75% glucose, we studied 100 ASA I or II patients who were scheduled for elective surgery to the lower limb and fulfilled the following criteria: age between 13 and 16 yr (Adolescent group, n = 40) or between 25 and 74 yr (Adult group, n = 60); height between 155 and 180 cm; and body mass index between 18 and 32 kg/m(2). Patients in each group were then randomly divided into two equal subgroups to receive spinal anesthesia with 0.5% tetracaine in either 7.5% or 0.75% glucose with 0.125% phenylephrine at the L3-4 interspace. With patients in the supine horizontal position, neural block was assessed by cold, pinprick, and touch sensation and a modified Bromage scale after the injection of the study drug. The 7.5% glucose solution produced a significantly higher and faster spread of blockade in adolescents than in adults. In contrast, there were no differences in the levels of three sensory modalities between the two age groups after the 0.75% glucose solution, which produced a lower spread of blockade than the 7.5% glucose solution in either age group. Adolescents given the 0.75% glucose solution developed a smaller maximum decrease in systolic pressure than those given the heavier solution. We conclude that adolescents may develop an extensive level of blockade more easily and quickly than adults after intrathecal hyperbaric tetracaine, but that the difference may be reduced by using a less heavy solution. The influence of age on the characteristics of spinal anesthesia is still controversial. Our results show that adolescents develop blockade more extensively and quickly than adults after spinal anesthesia with 0.5%tetracaine in 7.5% glucose but not after the 0.75% glucose solution.

Early oral intake after arthroscopic surgery under spinal anesthesia

We investigated the tolerability of early oral feeding (EOF) and its effects on the recovery of bowel function after spinal anesthesia. Thirty-one healthy adult patients undergoing knee arthroscopy or arthroscopic surgeries were randomly assigned to either the EOF group (n = 16) or the nil per os (NPO, n = 15) group. Spinal anesthesia was performed using hyperbaric tetracaine solution in all patients. Patients in the EOF group were allowed free access to solid and liquid food immediately after surgery before analgesia from spinal tetracaine resolved. Oral intake was prohibited for 24 h after completion of surgery in the NPO group. Two patients in each group were mildly nauseated without the need for treatment. While degree of appetite determined by a visual analog scale before the first meal and time to the first gas emission showed no significant differences between groups, the median time to the first defecation in the EOF group (20.6 h) was significantly shorter than that of the NPO group (33.5 h, P = 0.005). No other complications associated with anesthesia, surgery, or EOF were noted. Our results suggest that the restriction of EOF after surgery not involving the gastrointestinal tract under spinal anesthesia may not be rational, and that EOF may facilitate recovery of bowel function.

Effect of spinal versus general anesthesia on bladder compliance and intraabdominal pressure during transurethral procedures

Study Objective: To evaluate the influence of spinal versus general anesthesia on bladder compliance and intraabdominal pressure in elderly males undergoing elective transurethral resection of the prostate. Design: Prospective, randomized, open-label study. Setting: Teaching hospital. Patients: 21 ASA physical status I, II, and III patients at least 18 years of age, undergoing transurethral surgery. Interventions: According to a computer-generated randomization schedule, patients were allocated to one of two groups. In Group Spinal (S), 10 mg of hyperbaric tetracaine was administered intrathecally. In Group General Anesthesia (GA), patients received fentanyl intravenous (IV) 1 to 2 μg/kg and propofol IV 1.0 to 2.0 mg/kg for induction of anesthesia. Thereafter, a laryngeal mask airway was inserted and, with spontaneous ventilation, anesthesia was maintained by administering isoflurane (end-tidal 0.7% to 1.2%) and 70% nitrous oxide (N 2O) in oxygen. Intraabdominal pressure and bladder compliance were recorded prior to the induction of anesthesia and immediately before the onset of the surgical procedure. Measurements and Main Results: The two groups were demographically comparable. In Group S, mean bladder compliance was significantly (p = 0.003) higher and mean intraabdominal pressure significantly lower (p = 0.007) when compared to baseline preanesthetic values. In Group GA, mean intraabdominal pressure significantly (p = 0.006) decreased when compared to baseline preanesthetic recordings. Following the induction of general anesthesia, a small change in bladder compliance was noted. However, statistical significance was not reached. Data were analyzed and compared using Student’s t-test (p < 0.05 was considered statistically significant). Conclusion: Both spinal and general anesthesia induced a significant decrease in intraabdominal pressure. While both techniques were associated with an increase in bladder compliance, statistical significance was demonstrated only in the spinal anesthesia treatment group.

Spinal anesthesia for elective lumbar spine surgery

Study Objective: To evaluate a large series of elective lumbar spine surgical procedures by a single surgeon whose patients were all offered spinal anesthesia. Design: Retrospective chart review. Setting: Tertiary-care teaching hospital. Measurements and Main Results: The records of all elective lumbar spine procedures between 1984 and 1995 performed by one surgeon (GRB) were obtained, and 803 were identified. Of those 803 patients, 611 accepted spinal anesthesia. Data collected included patient demographics, details of the spinal and general anesthesia, perioperative complications, and impact of the spinal anesthetic options on the outcome of spinal anesthesia. General and spinal anesthesia patients were comparable for age, gender, height, and ASA physical status. Patients who received spinal anesthesia were significantly heavier than the general anesthesia patients. Among perioperative complications, nausea and deep venous thrombosis occurred significantly more often in the general than spinal anesthesia patients. Mild hypotension and decreased heart rate (HR) were the most common hemodynamic changes with spinal anesthesia, whereas hypertension and increased HR were the result of general anesthesia. Among spinal anesthetic drugs, plain bupivacaine was associated with the lowest incidence of supplemental local anesthetic use intraoperatively compared to hyperbaric bupivacaine or hyperbaric tetracaine. Conclusion: Spinal anesthesia is an effective alternative to general anesthesia for lumbar spine surgery and has a reduced rate of minor complications.

Oral Clonidine Premedication Enhances the Pressor Response to Ephedrine During Spinal Anesthesia

Clonidine premedication enhances the pressor effects of ephedrine in awake and anesthetized patients.To test the hypothesis that clonidine augments the pressor response to ephedrine during spinal anesthesia, 48 ASA physical status I or II patients were randomly assigned to either the clonidine group (n = 23), receiving oral clonidine approximately 5 [micro sign]g/kg 90 min before spinal anesthesia, or the control group (n = 25), receiving no clonidine. Spinal anesthesia was performed at either the L2-3 or the L3-4 interspace using 0.5% hyperbaric tetracaine solution 1.4-3.0 mL. Blood pressure (BP), heart rate, and the upper dermatomal level of analgesia were determined at 1-min intervals with the patient in the supine position after tetracaine injections. When systolic BP decreased to <80% of the prespinal value or <100 mm Hg, IV ephedrine 0.2 mg/kg was administered as a bolus. There were no differences in the duration until the first dose of ephedrine after tetracaine injections, and the upper level of analgesia between groups (control group 8.5 +/- 3.7 min, T5; clonidine group 7.7 +/- 2.7 min, T6). Although prespinal and preephedrine BP values were higher in the control group, the magnitude of increases in mean BP after ephedrine was significantly greater in the clonidine group (P < 0.05). We conclude that oral clonidine premedication augments the pressor response to IV ephedrine during spinal anesthesia. Implications: The pressor effect of ephedrine is enhanced in patients given oral clonidine premedication during spinal anesthesia. (Anesth Analg 1998;87:1336-9)

The Advantages of the Lateral Decubitus Position After Spinal Anesthesia with Hyperbaric Tetracaine

We investigated the effects of lateral decubitus positioning after spinal anesthesia with hyperbaric tetracaine on the spread of sensory blockade and hemodynamic variables. One hundred ASA physical status I or II patients scheduled for elective surgery to the lower limb received spinal anesthesia at a rate of approximately 0.1 mL/s using 0.5% tetracaine in 7.5% glucose with 0.125% phenylephrine in the lateral decubitus position with the operated side dependent. They were randomly divided into three groups: patients in Group I were placed supine immediately after spinal injection; those in Group II remained in the lateral position for 10 min before being turned supine; those in Group III were kept in the lateral position for 20 min then turned supine. Neural block was assessed by cold, pinprick, and touch sensation, and a modified Bromage scale. Hemodynamic variables included blood pressure, heart rate, and the use of ephedrine for the treatment of hypotension. The median (10th, 90th percentiles) peak dermatomal level to pinprick on the dependent side in Group III was T8 (T11, T5), which was significantly lower than that in Groups I and II, which extended to T4 (T9, T3) and T5 (T10, T2), respectively (P < 0.05). The difference in the maximal cephalad spread of sensory blockade between both sides in Group III was only one dermatome but was statistically significant (P < 0.05); in contrast, there was no significant difference in the maximal sensory level between both sides in Groups I and II. The use of ephedrine for the treatment of hypotension was significantly less frequent in Group III than the other groups. We conclude that keeping a patient in the lateral decubitus position for 20 min after hyperbaric tetracaine spinal anesthesia maintains preferential anesthetic distribution to the dependent side. Despite small differences between the two sides, the restricted spread of blockade and less hemodynamic variability may be clinically advantageous. The effects of posture on the spread of hyperbaric spinal anesthesia have not been adequately investigated. The results of the present study suggest an advantage of prolonged lateral decubitus positioning after intrathecal hyperbaric tetracaine.

The Advantages of the Lateral Decubitus Position After Spinal Anesthesia with Hyperbaric Tetracaine

We investigated the effects of lateral decubitus positioning after spinal anesthesia with hyperbaric tetracaine on the spread of sensory blockade and hemodynamic variables.One hundred ASA physical status I or II patients scheduled for elective surgery to the lower limb received spinal anesthesia at a rate of approximately 0.1 mL/s using 0.5% tetracaine in 7.5% glucose with 0.125% phenylephrine in the lateral decubitus position with the operated side dependent. They were randomly divided into three groups: patients in Group I were placed supine immediately after spinal injection; those in Group II remained in the lateral position for 10 min before being turned supine; those in Group III were kept in the lateral position for 20 min then turned supine. Neural block was assessed by cold, pinprick, and touch sensation, and a modified Bromage scale. Hemodynamic variables included blood pressure, heart rate, and the use of ephedrine for the treatment of hypotension. The median (10th, 90th percentiles) peak dermatomal level to pinprick on the dependent side in Group III was T8 (T11, T5), which was significantly lower than that in Groups I and II, which extended to T4 (T9, T3) and T5 (T10, T2), respectively (P < 0.05). The difference in the maximal cephalad spread of sensory blockade between both sides in Group III was only one dermatome but was statistically significant (P < 0.05); in contrast, there was no significant difference in the maximal sensory level between both sides in Groups I and II. The use of ephedrine for the treatment of hypotension was significantly less frequent in Group III than the other groups. We conclude that keeping a patient in the lateral decubitus position for 20 min after hyperbaric tetracaine spinal anesthesia maintains preferential anesthetic distribution to the dependent side. Despite small differences between the two sides, the restricted spread of blockade and less hemodynamic variability may be clinically advantageous. Implications: The effects of posture on the spread of hyperbaric spinal anesthesia have not been adequately investigated. The results of the present study suggest an advantage of prolonged lateral decubitus positioning after intrathecal hyperbaric tetracaine. (Anesth Analg 1998;87:879-84)

Spinal anesthesia for pediatrics

Spinal anesthesia for pediatrics first appeared at the beginning of 20th century. After an initial period of disuse, it has now gained popularity due to its favorable characteristics such as cardiovascular stability in children less than 5 years of age; satisfactory analgesia and muscle relaxation; the possibility of performing surgical procedures in patients at risk for general anesthesia (ie, formerly preterm infants at risk for postoperative apnea); and the ability to administer small doses of local anesthetic (preferably hyperbaric tetracaine or bupivacaine) with consequent reduced toxic effects. This technique is limited mainly by a relatively short duration of anesthesia (surgical procedures generally cannot last more than 90 min), by the absence of satisfactory postoperative pain control, and obviously by the lack of experience of anesthetist. Postdural puncture headache is rare. Although this technique could appear to be less invasive, we recommend an accurate, postoperative control for at least 12 hours.

Spinal Anesthesia With Tetracaine in 0.75% Glucose: Influence of the Vertebral Interspace Used for Injection

Background and ObjectivesThe anesthetic behavior and hemodynamic consequences of spinal anesthesia with marginally hyperbaric tetracaine containing a low concentration of glucose injected at two different interspaces were examined and compared with those of conventionally hyperbaric solution.MethodsOne-hundred twenty ASA Physical Status I or II patients scheduled for elective surgery to the lower limb were sequentially assigned to one of three equal groups to receive spinal anesthesia: Group 1 received 0.5% tetracaine in 0.75% glucose with 0.125% phenylephrine at the L2-L3 interspace; group 2 0.5% tetracaine in 0.75% glucose with 0.125% phenylephrine at the L3-L4 interspace; group 3 0.5% tetracaine in 7.5% glucose with 0.125% phenylephrine at the L3-L4 interspace. Neural block was assessed in a double-blinded manner by cold, pinprick, and touch sensation, and a modified Bromage scale after the injection of the study drug.ResultsInjection at the L2-L3 interspace produced significantly higher spread of analgesia [median T7 (10th, 90th percentiles T10, T4)] than injection at L3-L4 interspace [T10 (L1, T5)] when using the solution in 0.75% glucose. There were no significant differences in peak dermatomal levels between groups 1 and 3, but the number of patients who required ephedrine for the treatment of hypotension was larger in group 3.ConclusionsA marginally hyperbaric tetracaine solution injected at the L2-L3 interspace with the patient in the lateral position produced greater extent of cephalad spread than that at the L3-L4 interspace. When compared to a conventionally hyperbaric tetracaine solution injected at the L3-L4 interspace, the marginally hyperbaric solution injected at the L2-L3 interspace caused less hemodynamic variability despite similar levels of maximum sensory block.