Anesthetic management of thoracoscopic resection of lung lesions in small children.

BACKGROUND: Video-assisted thoracoscopic surgery has dramatically increased over the last decade because of both medical and cosmetic benefits. Anesthesia for video-assisted thoracoscopic surgery in small children is more challenging compared to adults due to the considerable problems posed by small airway dimensions and ventilation. The optimal technique for one-lung ventilation has yet to be established and the use of remifentanil infusion in this setting is not well described. AIMS: This study investigated the use of extraluminal bronchial blocker placement for one-lung ventilation and the effect of infusion of remifentanil in infants and small children undergoing video-assisted thoracoscopic surgery. METHODS: We retrospectively reviewed the technique of one-lung ventilation and the hemodynamic effects of remifentanil infusion in 31 small children during elective video-assisted thoracoscopic surgery for congenital lung lesions under anesthesia with sevoflurane or isoflurane, oxygen, and air. Patients' heart rate, blood pressure, and endtidal carbon dioxide at baseline (after induction of anesthesia), immediately after one-lung ventilation, during carbon dioxide insufflation, and at the end of one-lung ventilation were extracted from the database and analyzed. The use of vasopressors or dexmedetomidine was also recorded and analyzed. RESULTS: Extraluminal placement of a bronchial blocker alongside the tracheal tube was successfully performed in 90.3% of cases (28 patients) without any serious complications or arterial oxygen desaturation. There was no significant rise in blood pressure or heart rate even with the rise of endtidal carbon dioxide concentration during video-assisted thoracoscopic surgery. In 58% of patients (18 patients), phenylephrine was administered to maintain the blood pressure within 20% of the baseline value. There was no significant change in the heart rate of all patients at each time point. CONCLUSION: One-lung ventilation with an extraluminal parallel blocker was used effectively in this series of young children undergoing thoracoscopic excision of congenital pulmonary lesions. Remifentanil infusion attenuated surgical stress effectively in infants and small children undergoing video-assisted thoracoscopic surgery.

Thoracoscopic operations in children.

Over the past two decades there has been an exponential growth in the use of thoracoscopy in children. Indeed, many advanced procedures-including lobectomy, repair of tracheoesophageal fistula, excision of mediastinal tumours, and diaphragmatic hernia repairs-can now be performed by this means in advanced paediatric surgical centres in the world. This review describes the historical perspectives and the current state of thoracoscopic surgery, including potential benefits and challenges, in children.

Optimal timing for the administration of intranasal dexmedetomidine for premedication in children.

Previous studies have shown that 1 µg.kg(-1) intranasal dexmedetomidine produces significant sedation in children aged between 2 and 12 years. This investigation was designed to evaluate the onset time. One hundred children aged 1-12 years of ASA physical status 1-2 undergoing elective surgery were randomly allocated to five groups. Patients in groups A to D received intranasal dexmedetomidine 1 µg.kg(-1) . Patients in Group E received intranasal placebo (0.9% saline). Children from groups A, B, C, D and E had intravenous cannulation attempted at 30, 45, 60, 75 and 45 min respectively after intranasal drug or placebo administration. Vital signs, behaviour and sedation status of the children were assessed regularly until induction of anaesthesia. More children from groups A to D achieved satisfactory sedation at the time of cannulation when compared to group E (p < 0.001). The proportion of children who achieved satisfactory sedation was not significantly different among groups A to D. Overall 62% of the children who received intranasal dexmedetomidine had satisfactory sedation at the time of cannulation. The median (95% CI) time for onset of sedation was 25 (25-30) min. The median (95% CI) duration of sedation was 85 (55-100) min.

A comparison of intranasal dexmedetomidine and oral midazolam for premedication in pediatric anesthesia: a double-blinded randomized controlled trial.

BACKGROUND: Midazolam is the most commonly used premedication in children. It has been shown to be more effective than parental presence or placebo in reducing anxiety and improving compliance at induction of anesthesia. Clonidine, an alpha(2) agonist, has been suggested as an alternative. Dexmedetomidine is a more alpha(2) selective drug with more favorable pharmacokinetic properties than clonidine. We designed this prospective, randomized, double-blind, controlled trial to evaluate whether intranasal dexmedetomidine is as effective as oral midazolam for premedication in children. METHODS: Ninety-six children of ASA physical status I or II scheduled for elective minor surgery were randomly assigned to one of three groups. Group M received midazolam 0.5 mg/kg in acetaminophen syrup and intranasal placebo. Group D0.5 and Group D1 received intranasal dexmedetomidine 0.5 or 1 microg/kg, respectively, and acetaminophen syrup. Patients' sedation status, behavior scores, blood pressure, heart rate, and oxygen saturation were recorded by an observer until induction of anesthesia. Recovery characteristics were also recorded. RESULTS: There were no significant differences in parental separation acceptance, behavior score at induction and wake-up behavior score. When compared with group M, patients in group D0.5 and D1 were significantly more sedated when they were separated from their parents (P < 0.001). Patients from group D1 were significantly more sedated at induction of anesthesia when compared with group M (P = 0.016). CONCLUSIONS: Intranasal dexmedetomidine produces more sedation than oral midazolam, but with similar and acceptable cooperation.

A double-blind, crossover assessment of the sedative and analgesic effects of intranasal dexmedetomidine.

BACKGROUND: The alpha2-receptor agonist, dexmedetomidine, provides sedation with facilitated arousal and analgesia with no respiratory depression. These properties render it potentially useful for anesthesia premedication, although parenteral administration is not practical in this setting. We designed this study to evaluate the sedative, anxiolytic, analgesic, and hemodynamic effects of dexmedetomidine administered intranasally in healthy volunteers. METHODS: Koch's design for crossover trials (three-treatment and two-period design) was adopted. The study was double-blind and there were three treatment groups: A (placebo), B (intranasal dexmedetomidine 1 microg/kg) and C (intranasal dexmedetomidine 1.5 microg/kg). Each of the 18 subjects participated in two study periods. The study drug was administered intranasally after baseline observations of modified Observer Assessment of Alertness/Sedation Scale, visual analog scale of sedation, bispectral index, visual analog scale of anxiety, pain pressure threshold measured by an electronic algometer, systolic blood pressure (SBP) and diastolic blood pressure, heart rate, respiratory rate, and oxygen saturation. These were repeated during the course of the study. RESULTS: Intranasal dexmedetomidine was well tolerated. Both 1 and 1.5 microg/kg doses equally produced significant sedation and decreases in bispectral index, SBP, diastolic blood pressure, and heart rate when compared with placebo (P < 0.05). The onset of sedation occurred at 45 min with a peak effect at 90-150 min. The maximum reduction in SBP was 6%, 23%, and 21% for Groups A, B, and C respectively. There was no effect on pain pressure threshold, oxygen saturation or respiratory rate. Anxiolysis could not be evaluated as no subjects were anxious at baseline. CONCLUSION: The intranasal route is effective, well tolerated, and convenient for the administration of dexmedetomidine. Future studies are required to evaluate the possible role of the noninvasive route of administration of dexmedetomidine in various clinical settings, including its role as premedication prior to induction of anesthesia.

Desmopressin does not decrease blood loss and transfusion requirements in patients undergoing hepatectomy.

PURPOSE: To determine the effects of desmopressin on coagulation and blood loss in patients undergoing elective partial hepatectomy. METHODS: A randomized, controlled and double-blind study on 59 patients who received either 0.3 micro g x kg(-1) of desmopressin or an equal volume of normal saline (control) infused intravenously over 20 min after induction of general anesthesia. RESULTS: There was an increase in plasma levels of factors VIII and von Willebrand after the infusion of study drug in both groups (P < 0.001). The activated partial thromboplastin time was shortened in Group D whereas prothrombin time was prolonged in Group C; (P = 0.02). A large range of intraoperative blood loss (400-7128 mL) was observed, with no significant differences between groups. There were no changes in plasma electrolyte levels or osmolality. Transfusion requirements were similar in both groups. CONCLUSION: Desmopressin did not reduce intraoperative blood loss or transfusion requirements during hepatectomy despite raising clotting factor levels and improving tests of hemostasis.