Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2002
Preserved CO(2) reactivity and increase in middle cerebral arterial blood flow velocity during laparoscopic surgery in children.
In adult patients, the creation of pneumoperitoneum (PP) by means of carbon dioxide (CO(2)) insufflation leads to an increase in cerebral blood flow velocity (CBFV), which is thought to be caused by hypercapnia. We evaluated whether PP leads to an increase of CBFV in children, and whether this increase is directly related to PP. The effects of PP on middle cerebral artery blood flow velocity were investigated in 12 children (mean age 3 yr, range 15-63 mo) undergoing laparoscopic herniorrhaphy under general anesthesia with sevoflurane and nitrous oxide/oxygen. CBFV was measured by using transcranial Doppler ultrasonography. During CO(2) insufflation, the end-tidal CO(2) concentration was kept constant by adjustment of ventilation by increasing minute volume. The CBFV increased significantly at an intraabdominal pressure of 12 mm Hg compared with baseline from 68 +/- 11 cm/s to 81 +/- 12 cm/s (P < 0.05). CO(2) reactivity remained in the normal range (4.0% +/- 1.9%/mm Hg) during PP. We conclude that the induction of PP leads to an increase in middle cerebral artery blood flow velocity in young children independent from hypercapnia, whereas CO(2) reactivity remains normal. ⋯ Laparoscopic surgery is performed frequently in pediatric patients. Cerebral blood flow velocities increase during insufflation of the intraperitoneal cavity for minimally invasive surgery in children. The vasoreactivity as part of the cerebral autoregulation remains unaffected.
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Anesthesia and analgesia · Feb 2002
Case ReportsDiscitis associated with pregnancy and spinal anesthesia.
Discitis (inflammation of the intervertebral disk) most commonly develops as a rare complication of bacterial infection or chemical or mechanical irritation during spine surgery (1) with a postoperative incidence of 1%-2.8% (2). It is also a complication of discography-the intradiscal injection of saline or contrast material (3). The incidence of postdiscography discitis is 1%-4% (3); no cases have been reported when prophylactic antibiotics have been used, supporting the theory of bacterial contamination (3). Although it is controversial whether discitis can be caused by an aseptic or infectious process, recent data suggest that persistent discitis is almost always bacterial (4). Honan et al. (5) reported 16 cases of spontaneous discitis and reviewed another 52 patients from the literature. In their series, patients tended to have one or more comorbid conditions, such as diabetes, vertebral fracture, or a preexisting spine injury. Spontaneous discitis has also been associated with advanced age, IV drug abuse, IV access contamination, urinary tract infection, and immunocompromised states (5,6). No cases of infectious discitis associated with pregnancy and spinal anesthesia have been reported in the English literature. Discitis presents as spasmodic pain in the back that may be referred to the hips or groin (7). The pain may radiate to the lower extremities. The erythrocyte sedimentation rate is usually increased. Radiological changes in discitis include narrowing of the intervertebral disk space, vertebral sclerosis, and erosion of the end plates. The best diagnostic measure may be magnetic resonance imaging (MRI) or a combination of bone and gallium scanning (2). The mainstay for discitis treatment is pain control and antibiotics; surgical intervention is usually not required. Complications of discitis include intervertebral fusion, epidural abscess, and paralysis. ⋯ This is a case report of a disk infection (discitis) caused by the bacteria, Streptococcus bovis after spinal anesthesia for cesarean delivery. S. bovis rarely causes discitis, and spinal anesthesia for labor and delivery has not been reported as a cause of discitis.
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Anesthesia and analgesia · Feb 2002
Screening patients with prolonged neuromuscular blockade after succinylcholine and mivacurium.
Patients with pseudocholinesterase (BChE) variants may exhibit markedly prolonged paralysis after the administration of succinylcholine or mivacurium. We sought to evaluate to what extent molecular biology may contribute to the biological assessment of such patients. We conducted a prospective cohort study in patients referred to our center between 1995 and 1999 for prolonged neuromuscular blockade after mivacurium or succinylcholine. For each patient, phenotyping was performed with a conventional biochemical technique and molecular biology for the detection of the atypical mutation (A variant). Among the 36 patients referred, 31 had low BChE activity, 26 had received mivacurium (BChE activity, 2.1 U/mL; 0.3-4.3 U/mL), and 5 had received succinylcholine (BChE activity, 1.9 U/mL; 1.1-3.2 U/mL) (mean; extreme values). The mean clinical duration of paralysis was 90 min (40-140 min) after succinylcholine and 301 min (120-720 min) after mivacurium. Thirty-two patients had a BChE deficiency of genetic origin: 20 were homozygous (AA), 10 were heterozygous (UA) for the A variant, and 2 did not have the A mutation (UU). One heterozygous UA patient had normal BChE activity. Nine among the heterozygous UA and the two homozygous UU patients probably carried a not-screened variant. In most cases, biochemical diagnosis was sufficient to confirm the existence of constitutional deficiency; molecular biology improved the accuracy of diagnosis in 11 patients (30%) but had few or no clinical implications for the patient him- or herself. ⋯ Systematic screening for the pseudocholinesterase atypical variant by biochemical and DNA analysis after a prolonged neuromuscular blocking effect of succinylcholine or mivacurium shows that molecular biology could improve the diagnosis in approximately one third of patients, but with few clinical implications, compared with biochemical testing.
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Anesthesia and analgesia · Feb 2002
Age-stratified pharmacokinetics of ketorolac tromethamine in pediatric surgical patients.
Published data suggest that ketorolac pharmacokinetics are different in children than in adults. We sought to better characterize ketorolac pharmacokinetics in children. Thirty-six children, aged 1-16 yr, were stratified into four age groups: 1-3 yr, 4-7 yr, 8-11 yr, and 12-16 yr. Each child received 0.5 mg/kg of ketorolac tromethamine IV after completion of elective surgery. A maximum of 16 venous blood samples (mean, 13 +/- 2) were collected at predetermined times up to 10 h after drug administration. Plasma ketorolac concentrations were measured by high-performance liquid chromatography after solid-phase extraction. Individual concentration-versus-time relationships were best fit to a two-compartment pharmacokinetic model by using SAAM II. Body weight-normalized pharmacokinetic variables did not differ among the age groups and were similar to those reported for adults, including a volume of distribution at steady state of 113 +/- 33 mL/kg (mean +/- SD) and an elimination clearance of 0.57 +/- 0.17 mL x min(-1) x kg(-1). Our study demonstrates that a single dose of ketorolac (0.5 mg/kg) results in plasma concentrations in the adult therapeutic concentration range for 6 h in most children. Our data provide no evidence that children require either larger weight-adjusted doses or shorter dosing intervals than adults to provide similar plasma drug concentrations. ⋯ The literature suggests that ketorolac disposition differs between children and adults. We characterized ketorolac pharmacokinetics in 36 children. Body weight-normalized two-compartment pharmacokinetic variables did not differ among pediatric patients <17 yr old and were similar to adult values.
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Anesthesia and analgesia · Feb 2002
Case ReportsInterscalene and infraclavicular block for bilateral distal radius fracture.
Brachial plexus blockade is a suitable technique for surgery of the forearm, because it provides good intraoperative anesthesia as well as prolonged postoperative analgesia when long-acting local anesthetics are used. However, simultaneous blockade of both upper extremities has rarely been performed (1), because local anesthetic toxicity caused by the amount of drug needed to achieve an efficient block on both sides may be a problem. We report a case of successful bilateral brachial plexus block with ropivacaine in a patient with bilateral distal radius fracture, with each fracture requiring an open osteosynthesis. ⋯ This case report presents the performance of a simultaneous blockade of both upper extremities in a patient who sustained a bilateral distal radius fracture. The patient was known to be difficult to intubate and to have a severe hypersensitivity to opioids.