Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Comparative Study Clinical TrialSensorimotor anesthesia and hypotension after subarachnoid block: combined spinal-epidural versus single-shot spinal technique.
The extent of the intrathecal compartment depends on the balance between cerebrospinal fluid and subatmospheric epidural pressure. Epidural insertion disrupts this relationship, and the full impact of loss-of-resistance on the qualities of subarachnoid block is unknown. In this study we sought to determine if subarachnoid block, induced by combined spinal-epidural (CSE) using loss-of-resistance to air could render higher sensory anesthesia than single-shot spinal (SSS) when an identical mass of intrathecal anesthetic was injected. Sixty patients, scheduled for minor gynecological procedures, were randomly allocated into three groups all receiving 10 mg of 0.5% hyperbaric bupivacaine. In the SSS group, intrathecal administration was through a 27-gauge Whitacre spinal needle inserted at the L3-4 level. For the CSE group, the epidural space was identified with an 18-gauge Tuohy needle using loss-of-resistance to 4 mL of air. After intrathecal administration, a 20-gauge catheter was left in the epidural space. No further drug or saline was administered through the catheter. The procedure was repeated in group CSE ((no-catheter)) except without insertion of a catheter. Sensorimotor anesthesia was assessed at regular 2.5-min intervals until T10 was reached. In all aspects, there was no difference between CSE and CSE ((no-catheter)). Peak sensory level in SSS was lower than CSE and CSE ((no-catheter)) (median T5 [max T3-min T6] versus (T3 [T1-4] and (T3 [T2-5]) (P < 0.01). During the first 10 min postblock, dermatomal thoracic block was the lowest in SSS (P < 0.05). Time for regression of sensory level to T10 was also shortest in SSS. Hypotension, ephedrine use and period of motor recovery were more pronounced in CSE and CSE ((no-catheter)). We conclude that subarachnoid block induced by CSE produces greater sensorimotor anesthesia and prolonged recovery compared with SSS. There is also a more frequent incidence of hypotension and vasoconstrictor use despite using identical doses and baricity of local anesthetic. ⋯ This study confirms that induction of subarachnoid block by a combined-spinal epidural technique produces a greater sensorimotor anesthesia and results in prolonged recovery when compared with a single-shot spinal technique. There is a more frequent incidence of hypotension and vasoconstrictor administration despite identical doses of intrathecally administered local anesthetic.
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Anesthesia and analgesia · Feb 2004
Randomized Controlled Trial Clinical TrialIntravenous administration of flurbiprofen does not affect cerebral blood flow velocity and cerebral oxygenation under isoflurane and propofol anesthesia.
Flurbiprofen, a nonsteroidal antiinflammatory drug (NSAID), has been used to treat rheumatic and osteoarthritic pain and to reduce postoperative pain. Although other NSAIDs, such as indomethacin, reduce cerebral blood flow (CBF), the effect of flurbiprofen on CBF is unknown. In the present study, we investigated the effects of flurbiprofen on cerebral blood flow velocity (CBFV) and cerebral oxygenation under isoflurane or propofol anesthesia. Forty-eight patients undergoing orthopedic or abdominal surgery were enrolled. Patients were randomly allocated to receive either propofol (target control infusion: target site effect concentration 3 microg/mL) or isoflurane (1 MAC) for maintenance of anesthesia. In each group (n = 12), 1 mg/kg of flurbiprofen (PROP-F and ISO-F groups) or 0.1 mL/kg saline (PROP-S and ISO-S groups) was administered i.v. for 5 min. During and after the administration of flurbiprofen or saline, cerebral oxygenation variables (tissue oxygen index [TOI], total hemoglobin change [Delta cHb], oxygenated hemoglobin changes [Delta O(2)Hb], and deoxygenated hemoglobin changes [Delta HHb]), and middle cerebral artery flow velocity (Vmca) were measured using a cerebral oximeter (NIRO 300) and transcranial Doppler, respectively, from 5 min before study drug administration to 60 min post-administration. Before the administration of flurbiprofen, control values of TOI in the ISO-S and ISO-F groups were significantly higher than those in the PROP-S and PROP-F groups, respectively (ISO-S versus PROP-S, 67% +/- 4% versus 60% +/- 7%; IOS-F versus PROP-F, 69% +/- 4% versus 63% +/- 8%; P < 0.05). However, values of TOI, Delta cHb, Delta O(2)Hb, Delta HHb, and Vmca did not change significantly during and after the administration of flurbiprofen under propofol or isoflurane anesthesia, and these values were similar to those during and after the administration of saline in the same anesthesia group. These data indicate that flurbiprofen does not affect CBFV and cerebral oxygenation under propofol or isoflurane anesthesia. ⋯ Indomethacin, a nonsteroidal antiinflammatory drug (NSAID), has been demonstrated to reduce cerebral blood flow (CBF). The CBF effects of flurbiprofen, another NSAID, are unknown. We investigated cerebral blood flow velocity (CBFV) and cerebral oxygenation during and after the administration of flurbiprofen under isoflurane and propofol anesthesia. We found that flurbiprofen had no effect on CBFV and cerebral oxygenation.
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Anesthesia and analgesia · Feb 2004
Case ReportsReversal of an unintentional spinal anesthetic by cerebrospinal lavage.
In this case report, we describe the use of cerebrospinal fluid lavage as a successful treatment of an inadvertent intrathecally placed epidural catheter in a 14-yr-old girl who underwent a combination of epidural anesthesia and general anesthesia for orthopedic surgery. In this case, a large amount of local anesthetic was injected (the total possible intrathecal injection was 200 mg of lidocaine and 61 mg of bupivacaine), resulting in apnea and fixed dilated pupils in the patient at the end of surgery. Twenty milliliters of cerebrospinal fluid was replaced with 10 mL of normal saline and 10 mL of lactated Ringer's solution from the "epidural" catheter. Spontaneous respiration returned 5 min later, and the patient was tracheally extubated after 30 min. No signs of neurological deficit or postdural puncture headache were noted after surgery. ⋯ Cerebrospinal lavage may be a helpful adjunct to the conventional supportive management of patients in the event of an inadvertent total spinal.
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Anesthesia and analgesia · Feb 2004
Case ReportsSevere hypotension in the prone position in a child with neurofibromatosis, scoliosis and pectus excavatum presenting for posterior spinal fusion.
A 34-mo-old boy with neurofibromatosis, scoliosis, and pectus excavatum developed severe hypotension when positioned prone. A magnetic resonance image study revealed neurofibromas encircling the great vessels. During the next anesthetic the patient was placed in the prone position on transverse bolsters and hypotension ensued again. A transesophageal echocardiogram (TEE) revealed compression of the right ventricle by the sternum. When the child was turned supine, the blood pressure returned to baseline. The patient was returned to the prone position, this time with bolsters placed longitudinally, without problem. This case supports a cardiac evaluation, possible intraoperative TEE, and avoidance of sternal pressure in patients with chest wall deformities requiring prone positioning. ⋯ A child with neurofibromatosis, scoliosis, and a chest wall deformity presenting for spinal fusion developed severe hypotension while prone. This was due to compression of the heart by the sternum, not compression of the great vessels by neurofibromas. Sternal pressure in prone patients with chest wall deformities should be avoided. Unique management included the use of transesophageal echocardiography to determine the cause of the hypotension.
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Anesthesia and analgesia · Feb 2004
Case ReportsGrand mal convulsion after an accidental intravenous injection of ropivacaine.
A 36-yr old, ASA physical status I patient scheduled for hip arthroplasty under regional anesthesia received at the end of surgery an i.v. injection of approximately 200 mL of a 0.15% ropivacaine solution (300 mg = 4.6 mg/kg) in approximately 5 min. The bag prepared for postoperative epidural infusion was accidentally connected to a peripheral i.v. line. The patient developed grand mal convulsions, hypotension, and respiratory arrest. No arrhythmias were observed. Twenty minutes after the event, the arterial plasma concentration of ropivacaine was 3.10 microg/mL. Using a pharmacokinetic model, the peak plasma concentration at the time of the accidental administration was estimated at 17.04 microg/mL. The patient recovered uneventfully. ⋯ An accidental i.v. injection of approximately 300 mg of ropivacaine was followed by seizures without any arrhythmia. The patient recovered uneventfully.