Anesthesia and analgesia
-
Anesthesia and analgesia · May 2001
Randomized Controlled Trial Clinical TrialThe safety and efficacy of sevoflurane anesthesia in infants and children with congenital heart disease.
We tested the hypothesis that sevoflurane is a safer and more effective anesthetic than halothane during the induction and maintenance of anesthesia for infants and children with congenital heart disease undergoing cardiac surgery. With a background of fentanyl (5 microg/kg bolus, then 5 microg. kg(-1). h(-1)), the two inhaled anesthetics were directly compared in a randomized, double-blinded, open-label study involving 180 infants and children. Primary outcome variables included severe hypotension, bradycardia, and oxygen desaturation, defined as a 30% decrease in the resting mean arterial blood pressure or heart rate, or a 20% decrease in the resting arterial oxygen saturation, for at least 30 s. There were no differences in the incidence of these variables; however, patients receiving halothane experienced twice as many episodes of severe hypotension as those who received sevoflurane (P = 0.03). These recurrences of hypotension occurred despite an increased incidence of vasopressor use in the halothane-treated patients than in the sevoflurane-treated patients. Multivariate stepwise logistic regression demonstrated that patients less than 1 yr old were at increased risk for hypotension compared with older children (P = 0.0004), and patients with preoperative cyanosis were at increased risk for developing severe desaturation (P = 0.049). Sevoflurane may have hemodynamic advantages over halothane in infants and children with congenital heart disease. ⋯ In infants and children with congenital heart disease, anesthesia with sevoflurane may result in fewer episodes of severe hypotension and less emergent drug use than anesthesia with halothane.
-
Anesthesia and analgesia · May 2001
Randomized Controlled Trial Clinical TrialThe effect of intranasal fentanyl on the emergence characteristics after sevoflurane anesthesia in children undergoing surgery for bilateral myringotomy tube placement.
Children undergoing placement of bilateral myringotomy tubes (BMT) often exhibit pain-related behavior (agitation) in the postanesthesia care unit. We compared the emergence and recovery profiles of pediatric patients who received sevoflurane with or without supplementary intranasal fentanyl for BMT surgery. By using a prospective, double-blinded design, 150 children 6 mo to 5 yr of age, scheduled for routine BMT surgery, were anesthetized with sevoflurane (2%-3%) in a 60% N(2)O/O(2) gas mixture. Patients were randomized to receive equal volumes of intranasal saline (Control), 1 microg/kg fentanyl or 2 microg/kg fentanyl. A blinded observer evaluated each patient using a previously described 4-point agitation scale and the Steward recovery scale. Response to parental presence was observed after a score of six (full recovery) was achieved on the Steward recovery scale. There were no significant differences among the three groups regarding age, weight, surgeon, duration of anesthesia, or ear condition. Recovery times and emergence characteristic scores were not statistically different. Agitation scores were significantly reduced in the 2-microg/kg Fentanyl group as compared with the Control group (P = 0.012). Fentanyl 2 microg/kg is recommended to reduce the incidence of agitation seen in these patients. ⋯ We examined the use of nasally administered fentanyl for the relief of agitation or discomfort after placement of bilateral myringotomy tubes in 150 children ages 6 mo to 5 yr using a prospective, double-blinded design. Fentanyl 2 microg/kg was found to reduce the incidence of agitation in these patients.
-
Anesthesia and analgesia · May 2001
The effects of prone positioning on intraabdominal pressure and cardiovascular and renal function in patients with acute lung injury.
To detect any harmful effects of prone positioning on intraabdominal pressure (IAP) and cardiovascular and renal function, we studied 16 mechanically ventilated patients with acute lung injury randomly in prone and supine positions, without minimizing the restriction of the abdomen. Effective renal blood flow index and glomerular filtration rate index were determined by the paraaminohippurate and inulin clearance techniques. Prone positioning resulted in an increase in IAP from 12 +/- 4 to 14 +/- 5 mm Hg (P < 0.05), PaO(2)/fraction of inspired oxygen from 220 +/- 91 to 267 +/- 82 mm Hg (P < 0.05), cardiac index from 4.1 +/- 1.1 to 4.4 +/- 0.7 L/min (P < 0.05), mean arterial pressure from 77 +/- 10 to 82 +/- 11 mm Hg (P < 0.01), and oxygen delivery index from 600 +/- 156 to 648 +/- 95 mL. min(-)(1). m(-)(2) (P < 0.05). Renal fraction of cardiac output decreased from 19.1% +/- 12.5% to 15.5% +/- 8.8% (P < 0.05), and renal vascular resistance index increased from 11762 +/- 6554 dynes. s. cm(-)(5). m(2) to 15078 +/- 10594 dynes. s. cm(-)(5). m(2) (P < 0.05), whereas effective renal blood flow index, glomerular filtration rate index, filtration fraction, urine volume, fractional sodium excretion, and osmolar and free water clearances remained constant during prone positioning. Prone positioning, when used in patients with acute lung injury, although it is associated with a small increase in IAP, contributes to improved arterial oxygenation and systemic blood flow without affecting renal perfusion and function. Apparently, special support to allow free chest and abdominal movement seems unnecessary when mechanically ventilated, hemodynamically stable patients without abdominal hypertension are proned to improve gas exchange. ⋯ Prone positioning is increasingly used to improve gas exchange in patients with acute lung injury. However, during prone positioning an increase in intraabdominal pressure in these critically ill patients may promote dysfunction of other organs. Therefore, we performed a randomized study in mechanically ventilated patients with acute lung injury to investigate the cardiovascular and renal effects of prone positioning.
-
Anesthesia and analgesia · May 2001
Randomized Controlled Trial Clinical TrialSmall-dose S(+)-ketamine reduces postoperative pain when applied with ropivacaine in epidural anesthesia for total knee arthroplasty.
Reduction of nociceptive input through blockade of N-methyl-D-aspartate (NMDA) receptors has been reported. We compared the effects of epidural S(+)-ketamine versus placebo on postoperative pain in a randomized, double-blinded study in 37 patients undergoing unilateral knee arthroplasty. After lumbar epidural anesthesia with ropivacaine (10 mg/mL, 10-20 mL), 19 patients received 0.9% epidural saline, and 18 patients received 0.25 mg/kg epidural S(+)-ketamine 10 min before surgical incision. After surgery, patient-controlled epidural analgesia with ropivacaine was provided. During the first 8 h after surgery, visual analog scale pain rating was similar between groups. Twenty-four and 48 h after surgery, patients anesthetized with ropivacaine had higher visual analog scale ratings at rest and during movement (P < 0.05) than patients anesthetized with S(+)-ketamine and ropivacaine. Forty-eight hours after surgery, patients anesthetized with ropivacaine also consumed more ropivacaine (558 +/- 210 mg) (P < 0.01) than those anesthetized with S(+)-ketamine and ropivacaine (319 +/- 204 mg). Adverse events were similar between groups. Patients who received S(+)-ketamine and ropivacaine rated the quality of their pain therapy better than those who received ropivacaine alone (P < 0.05). We conclude that the combination of S(+)-ketamine and ropivacaine in epidural anesthesia increases postoperative pain relief when compared with ropivacaine. ⋯ Epidural S(+)-ketamine applied with ropivacaine before surgery is a rational approach to decrease injury-induced pain sensitization. Epidural blockade with an N-methyl-D-aspartate receptor antagonist and a local anesthetic may provide better analgesia in the postoperative period than a local anesthetic alone.