Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialUltrasound guidance speeds execution and improves the quality of supraclavicular block.
In this prospective study, we assessed the quality, safety, and execution time of supraclavicular block of the brachial plexus using ultrasonic guidance and neurostimulation compared with a supraclavicular technique that used anatomical landmarks and neurostimulation. It was hypothesized that ultrasonic guidance would increase the proportion of successful blocks, decrease block execution time, and reduce the incidence of complications such as pneumothorax and neuropathy. Eighty patients were randomized into two groups of 40, Group US (supraclavicular block guided in real time by a two-dimensional ultrasonic image, with neurostimulator confirmation of correct needle position) and Group NS (supraclavicular block using the subclavian perivascular approach, also with neurostimulator confirmation). Blocks were performed using bupivacaine 0.5% and lidocaine 2% (1:1 vol) with epinephrine 1:200000 as the anesthetic mixture. The onset of motor and sensory block for the musculocutaneous, median, radial, and ulnar nerves was evaluated over a 30 min period. At 30 min 95% of patients in Group US and 85% of patients in Group NS had a partial or complete sensory block of all nerve territories (P = 0.13) and 55% of patients in Group US and 65% of patients in Group NS had a complete block of all nerve territories (P = 0.25). Surgical anesthesia without supplementation was achieved in 85% of patients in Group US and 78% of patients in Group NS (P = 0.28). No patient in Group US and 8% of patients in Group NS required general anesthesia (P = 0.12). The quality of ulnar block was significantly inferior to the quality of block in other nerve territories in Group NS, but not in Group US; the quality of ulnar block was not significantly different between Groups NS and US. The block was performed in an average of 9.8 min in Group NS and 5.0 min in Group US (P = 0.0001). No major complication occurred in either group. We conclude that ultrasound-guided neurostimulator-confirmed supraclavicular block is more rapidly performed and provides a more complete block than supraclavicular block using anatomic landmarks and neurostimulator confirmation. ⋯ Ultrasound-guided neurostimulator-confirmed supraclavicular block is more rapidly performed and provides a block of better quality than supraclavicular block using anatomic landmarks and neurostimulator confirmation.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialIntrathecal morphine for postoperative analgesia: a randomized, controlled, dose-ranging study after hip and knee arthroplasty.
In this series, we examined analgesia and side effects of intrathecal morphine sulfate (ITMS) after hip and knee arthroplasty over a dose range of 0.0-0.3 mg. Eighty patients undergoing hip (n = 40) or knee (n = 40) arthroplasty were randomized to receive ITMS (0.0, 0.1, 0.2, or 0.3 mg). A patient-controlled analgesia (PCA) device provided free access to additional analgesics. Morphine use, pain relief, and side effects were recorded for 24 h. Data were analyzed with analysis of variance and linear regression. After hip arthroplasty, morphine use was less in patients receiving 0.1, 0.2, or 0.3 mg of ITMS than in control patients (P < 0.05). After knee arthroplasty, ITMS did not reduce postoperative morphine requirements. Nausea and vomiting and the incidence of oxygen saturation <93% were similar in all groups. Pruritus was more common after ITMS. Patients receiving 0.2 or 0.3 mg of ITMS were more satisfied with their pain control than those receiving 0.0 or 0.1 mg after both hip and knee arthroplasty. Analgesic needs are greater after knee arthroplasty than after hip arthroplasty. We conclude that combining small-dose (0.2 mg) ITMS with PCA morphine provides good to excellent pain control in most patients after total hip or knee arthroplasty. However, PCA morphine use was reduced by the addition of ITMS only after hip arthroplasty. ⋯ This series examined the need for supplemental analgesics, the quality of analgesia, and the incidence of side effects with intrathecal morphine sulfate (ITMS) for analgesia after hip and knee arthroplasty. Analgesic needs are greater after knee arthroplasty than hip arthroplasty. Combining small-dose (0.2 mg) ITMS with standard doses of PCA morphine provided good to excellent pain control in most patients and reduced patient-controlled analgesia morphine use after hip, but not knee, arthroplasty.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialControlled hypotension and minimal inflation pressure: a new approach for pneumatic tourniquet application in upper limb surgery.
Minimal inflation pressures are recommended for limb surgery to eliminate complications attributable to high inflation pressures with the pneumatic tourniquets. We applied controlled hypotension and a minimal inflation pressure (CHAMIP) technique to provide a bloodless surgical field. Thirty-six patients scheduled for upper extremity surgery were randomized equally to receive either normotensive anesthesia and conventional inflation pressures or controlled hypotension (systolic arterial blood pressure of 80-100 mm Hg and mean arterial blood pressure >60 mm Hg) and minimum inflation pressures. Anesthesia was induced with propofol IV bolus and remifentanil IV continuous infusion and maintained with propofol and remifentanil IV continuous infusion. To determine the minimal inflation pressure, the digital plethysmograph was applied to the second finger at the side of the operation and the tourniquet was inflated slowly until the arterial pulsations disappeared on the oscilloscope. A bloodless surgical field was obtained in almost all patients, even though systolic arterial blood pressures (100-138 mm Hg versus 80-100 mm Hg) and applied tourniquet inflation pressures (270 mm Hg versus 110-140 mm Hg) were significantly lower in the hypotensive group. No complications associated with controlled hypotension were encountered. In conclusion, CHAMIP may be a safe and reliable method for upper extremity surgery performed with pneumatic tourniquets. ⋯ Pneumatic tourniquets are associated with adverse effects resulting from high inflation pressures. Therefore, minimal inflation pressures are recommended in extremity surgery. To reach real minimal inflation pressure the patient's blood pressure must be reduced. We used controlled hypotension with remifentanil and propofol to reach minimal inflation pressures.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Clinical TrialA silicone-based wire-reinforced tracheal tube with a hemispherical bevel reduces nasal morbidity for nasotracheal intubation.
We tested the hypothesis that a silicone-based wire-reinforced tracheal tube with a hemispherical bevel is superior to a polyvinyl chloride (PVC)-based precurved tube with a conventional diagonal bevel for nasotracheal intubation. Eighty anesthetized paralyzed adults (ASA physical status I-II) requiring nasotracheal intubation for tonsillectomy were randomly allocated into two equal-sized groups for airway management with the silicone tracheal tube or PVC tracheal tube. Intubation was subdivided into three phases: 1). passage through the nose into the pharynx, 2). laryngoscope-guided passage into the glottic inlet, and 3). laryngoscope-guided passage into the trachea. A specific sequence of airway maneuvers was followed at each stage if it was unsuccessful. The number of attempts and intubation time were documented by an unblinded observer. The frequency of epistaxis and postoperative nasal complications was documented by blinded observers. There were no intubation failures. The number of attempts at pharyngeal (47 versus 56; P = 0.04) and tracheal (43 versus 55; P = 0.005) placement was smaller for the silicone tracheal tube, but the number of attempts at glottic placement was more (72 versus 49; P < 0.0001). Intubation time was similar. The frequency (32% versus 80%; P < 0.0001) and severity of epistaxis were less for the silicone tracheal tube. The total number of postoperative nasal symptoms was smaller for the silicone tracheal tube (10 versus 21; P < 0.05). We conclude that the pharyngeal and tracheal placement phases of nasotracheal intubation require fewer attempts with the silicone tracheal tube than the PVC tracheal tube but that the glottic placement phase requires more attempts. Nasal morbidity is less common with the silicone tracheal tube. ⋯ The pharyngeal and tracheal placement phases of nasotracheal intubation require fewer attempts with a silicone-based wire-reinforced tracheal tube with a hemispherical bevel than with a polyvinyl chloride-based precurved tracheal tube with a conventional diagonal bevel, but the glottic placement phase requires more attempts. Nasal morbidity is less common with the silicone tracheal tube.
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Anesthesia and analgesia · Nov 2003
Clinical TrialPulse contour analysis for cardiac output monitoring in cardiac surgery for congenital heart disease.
Conventional methods of cardiac output monitoring using pulmonary artery catheters may not be feasible in patients with congenital heart disease because of patients' small size or aberrant anatomy. We studied the accuracy of a new device, which uses pulse contour analysis to measure continuous cardiac output, in children and adults undergoing congenital heart surgery. Sixteen patients, median ages 7 yr old, were included in this prospective study. One-hundred-ninety-one data points were obtained in the pre- and postcardiopulmonary bypass periods and in the first 12 h after intensive care unit admission. We evaluated the relationship between cardiac index (CI) derived from transpulmonary thermodilution (TDCI) and CI derived from pulse contour analysis (PCCI). Bias and limits of agreement between TDCI and PCCI over all time periods were 0.1 +/- 1.94, indicating a wide dispersion of the data. Coefficient of correlation (r) between the TDCI and PCCI was 0.7. Although in previous studies, PCCI has been suggested to be accurate in adult cardiac surgery, we found it to be less reliable in our study patients, even after shunt correction. The relationships of the volume and pressure based measures of preload, intrathoracic blood volume index (ITBI), and central venous pressure with CI were also investigated. After repair, correlation (r) between PCCI or TDCI and ITBI (0.56 and 0.71, respectively) was better than that between PCCI or TDCI and CVP (0.16 and 0.11, respectively), indicating greater validity of ITBI as a measure of preload. ⋯ Our results suggest that the pulse contour analysis cardiac output (CO) monitoring in patients undergoing congenital heart surgery may not provide as accurate or reliable measures of CO as previously suggested. The volume-based variable of preload intrathoracic blood volume index (ITBI) has better correlation with cardiac index (CI) than the central venous pressure, suggesting that ITBI may be a better indicator of preload.