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 ReportsDifficult retrograde endotracheal intubation: the utility of a pharyngeal loop.
Direct laryngoscopy and tracheal intubation remains the technique of choice to achieve control of the airway. Alternative or additional techniques of airway control are required whenever an airway is deemed difficult because of anatomical and/or technical reasons. The retrograde intubation technique is an important option for gaining airway access from below the vocal cords in such situations (1). We report successful management and the problems encountered while gaining the upper airway by the retrograde catheter method in a patient having bilateral fibrous ankylosis of the temporomandibular joint (TMJ). ⋯ A 30-yr-old woman presented for redo-release of bilateral temporomandibular joint ankylosis under general anesthesia. During the previous anesthetic for primary release of ankylosis, tracheostomy was done, as conventional blind nasotracheal and retrograde intubation attempts failed several times. This case report describes the method for overcoming the difficulties of a retrograde intubation procedure in removing the guiding catheter nasally by using a pharyngeal loop assembly.
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Anesthesia and analgesia · Feb 2002
An evaluation of the cutaneous distribution after obturator nerve block.
In 1973, Winnie et al. introduced the inguinal paravascular three-in-one block, which allegedly provides anesthesia of three nerves--the femoral, lateral cutaneous femoral, and obturator nerves--with a single injection. This concept was undisputed until the success of the obturator nerve block was reassessed by using evidence of adductor weakness rather than cutaneous sensory blockade, the latter being variable in its distribution and often absent. We performed this study, therefore, to evaluate the area of sensory loss produced by direct injection of local anesthetic around the obturator nerve. A selective obturator nerve block with 7 mL of 0.75% ropivacaine was performed in 30 patients scheduled for knee surgery. Sensory deficit and adductor strength were evaluated for 30 min by using sensory tests (cold and light-touch perception) and the pressure generated by the patient's squeezing a blood pressure cuff placed between the knees. Subsequently, a three-in-one block was performed, and the sensory deficit was reassessed. The obturator nerve block was successful in 100% of cases. The strength of adductors decreased by 77% +/- 17% (mean +/- SD). In 17 patients (57%), there was no cutaneous contribution of the obturator nerve. The remaining 7 patients (23%) had an area of hypoesthesia (cold sensation was blunt but still present) on the superior part of the popliteal fossa, and the other 6 (20%) had sensory deficit located at the medial aspect of the thigh. The three-in-one block resulted in blockade of the lateral aspect of the thigh in 87% of cases, whereas the anteromedial aspect was always anesthetized. By use of magnetic resonance imaging in eight volunteers, we demonstrated that the obturator nerve has already divided into its two branches at the site of local anesthetic injection. However, the injection of blue dye after having simulated the technique in five cadavers showed that the fluid regularly spread to both branches. We conclude that after three-in-one block, a femoral nerve block may have been assessed as an obturator nerve block in 100% of cases when testing the cutaneous distribution of the obturator nerve on the medial aspect of the thigh. ⋯ Previous studies reporting an incidence of obturator nerve block after three-in-one block may have mistaken a femoral nerve block for an obturator nerve block in 100% of cases when the cutaneous distribution of the obturator nerve was assessed on the medial aspect of the thigh. The only way to effectively evaluate obturator nerve function is to assess adductor strength.
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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.
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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.