Nitrous Oxide Induces Prominent Cell Proliferation in Adult Rat Hippocampal Dentate Gyrus.

The identification of distinct and more efficacious antidepressant treatments is highly needed. Nitrous oxide (N2O) is an N-methyl-D-aspartic acid (NMDA) antagonist that has been reported to exhibit antidepressant effects in treatment-resistant depression (TRD) patients. Yet, no studies have investigated the effects of sub-anesthetic dosages of N2O on hippocampal cell proliferation and neurogenesis in adult brain rats. In our study, adult male Sprague-Dawley rats were exposed to single or multiple exposures to mixtures of 70% N2O and 30% oxygen (O2). Sham groups were exposed to 30% O2 and the control groups to atmospheric air. Hippocampal cell proliferation was assessed by bromodeoxyuridine (BrdU) incorporation, and BrdU-positive cells were counted in the dentate gyrus (DG) using confocal microscopy. Results showed that while the rates of hippocampal cell proliferation were comparable between the N2O and sham groups at day 1, levels increased by 1.4 folds at day 7 after one session exposure to N2O. Multiple N2O exposures significantly increased the rate of hippocampal cell proliferation to two folds. Therefore, sub-anesthetic doses of N2O, similar to ketamine, increase hippocampal cell proliferation, suggesting that there will ultimately be an increase in neurogenesis. Future studies should investigate added N2O exposures and their antidepressant behavioral correlates.

Phantom limb pain in young cancer-related amputees: recent experience at St Jude children's research hospital.

OBJECTIVES: This study in children and young adults having cancer-related amputation aimed to examine the incidence of phantom limb pain (PLP) in the first year after amputation and also the proportion of patients who had preamputation pain. METHODS: A retrospective review of medical records was undertaken. The proportion of patients with PLP was reported. Fisher exact test was used to examine the association between PLP and the presence of preamputation pain and between PLP and age (≤ 18 y vs. >18 y). RESULTS: Twenty-six amputations were performed on 25 patients. During the year after amputation, 76% of patients had experienced PLP at some time. After 1 year, though, only 10% still had PLP. Preamputation pain was present in 64% of patients. Although both of our patients with PLP at 1 year were young adults (older than or equal to 18 y) and both had preamputation pain, we found no statistically significant associations between age or the presence of preamputation pain with PLP. DISCUSSION: PLP after cancer-related amputation in children and young adults seems to be common but generally short lived in most patients.

Prevention of emergence agitation in seven children receiving low-dose ketamine and propofol total intravenous anesthesia.

Emergence agitation (EA) can be a distressing side effect of pediatric anesthesia. We retrospectively reviewed the records of 7 pediatric oncology patients who received low-dose ketamine in conjunction with propofol for total intravenous anesthesia (TIVA) repeatedly for radiation therapy. EA signs were observed in all 7 patients in association with propofol TIVA but did not recur in any of 123 subsequent anesthetics sessions during which low-dose ketamine was added to propofol. Based on this experience, we suggest that low-dose ketamine added to propofol may be associated with prevention of EA in children with a history of EA with propofol TIVA.

Complications of anesthesia for children with malignant infantile osteopetrosis before and after hematopoietic stem cell transplantation.

OBJECTIVES AND AIMS: The primary aim was to determine the frequency of anesthetic-related complications for patients with malignant infantile osteopetrosis (MIOP) before and after hematopoietic stem cell transplant (HSCT). The secondary aims were to describe the types of complications that occurred, to determine whether the risk of anesthetic complications was altered by HSCT, and to determine the frequency of difficult intubation. BACKGROUND: Patients with MIOP undergo HSCT, often in infancy, and anesthesia is frequently required for investigations and procedures associated with transplantation. Although MIOP has adverse implications for anesthetic management, the literature describing the anesthetic management of MIOP patients is limited. METHODS: A retrospective review of medical and anesthetic records was undertaken between November 2000 and March 2008. RESULTS: Eleven patients underwent 127 anesthetics. The overall complication rate was 11%. Before HSCT, there were 12 complications in 62 anesthetics (19.3%). After HSCT, there were two complications in 65 anesthetics (3.2%). This difference was not statistically significant. All of the complications were airway or respiratory events. Of the 26 intubations associated with anesthesia, 23 (88.5%) were easy, 1 (3.8%) was moderately difficult, and 2 (7.7%) were difficult. CONCLUSION: Complications associated with anesthesia for infants and children with MIOP having HSCT are fairly common and are usually airway or respiratory related. Difficult endotracheal intubation is also common.

Safe anesthesia for radiotherapy in pediatric oncology: St. Jude Children's Research Hospital Experience, 2004-2006.

PURPOSE: To determine the incidence of anesthesia-related complications in children undergoing radiotherapy and the associated risk factors. METHODS AND MATERIALS: We retrospectively investigated the incidence and types of anesthesia-related complications and examined their association with age, weight, oncology diagnosis, type of anesthetic (propofol vs. propofol and adjuncts), total propofol dose, anesthetic duration, type of radiotherapy procedure (simulation vs. radiotherapy) and patient position (prone vs. supine). RESULTS: Between July 2004 and June 2006, propofol was used in 3,833 procedures (3,611 radiotherapy sessions and 222 simulations) in 177 patients. Complications occurred during 49 anesthetic sessions (1.3%). On univariate analysis, four factors were significantly associated with the risk of complications: procedure duration (p <0.001), total propofol dose (p <0.001), use of adjunct agents (vs. propofol alone; p = 0.029), and simulation (vs. radiotherapy; p = 0.014). Patient position (prone vs. supine) was not significantly associated with the frequency of complications (odds ratio, 0.71; 95% confidence interval, 0.33-1.53; p = 0.38). On multivariate analysis, the procedure duration (p <0.0001) and total propofol dose (p < or =0.03) were the most significant risk factors after adjustment for age, weight, anesthetic type, and procedure type. We found no evidence of the development of tolerance to propofol. CONCLUSION: The rate of anesthesia-related complications was low (1.3%) in our study. The significant risk factors were procedure duration, total propofol dose, the use of adjunct agents with propofol, and simulation (vs. radiotherapy).

Isosulfan blue causes factitious methemoglobinemia in an infant.

A 9 month-old girl was given subcutaneous isosulfan blue to outline lymphatic channels during surgery for thoracic duct ligation. Her pulse oximetry values rapidly declined to a nadir of 85%, 35 min after dye injection. Arterial blood gases revealed methemoglobinemia ([MetHb] = 6.5%). Although abnormal pulse oximetry has already been reported in association with isosulfan blue, methemoglobinemia has not previously been reported. The absorption spectrum for isosulfan blue was determined and when superimposed on that of methemoglobin it was found to have an overlying peak. Interference by the dye was postulated to have caused the abnormal methemoglobin result. The phenomenon was simulated in vitro by adding isosulfan blue to whole blood, and analysing it in the same blood gas analyser as was used for the case, as well as another for comparison. One blood gas analyser reported elevated methemoglobin concentration and the other did not. The samples were sent to a reference laboratory using a chemical method to detect methemoglobin to confirm that the elevated methemoglobin level was spurious.

A clinical trial demonstrates the analgesic activity of intravenous parecoxib sodium compared with ketorolac or morphine after gynecologic surgery with laparotomy.

OBJECTIVE: The purpose of this study was to compare the analgesic activity of 2 doses of parecoxib sodium, ketorolac, and morphine with placebo after gynecologic surgery that requires laparotomy. STUDY DESIGN: In a randomized, controlled, double-blind, parallel-group study, 208 patients, after surgical hysterectomy, received single-dose intravenous placebo, parecoxib sodium 20 mg or 40 mg, ketorolac 30 mg, or morphine 4 mg followed by multiple-dose parecoxib sodium or ketorolac as needed. Primary efficacy variables were time to onset of analgesia, pain intensity differences, pain relief, time to first rescue/remedication, and global evaluation of study medication. RESULTS: Single-dose parecoxib sodium 40 mg provided significantly better pain responses to placebo or morphine 4 mg and was comparable to ketorolac 30 mg. Multiple-dose parecoxib sodium 20 mg, 4 times daily, or 40 mg, twice daily, was comparable to ketorolac 30 mg, 4 times daily. Parecoxib sodium was well tolerated. CONCLUSION: Parecoxib sodium is an effective analgesic in the management of acute postoperative pain after laparotomy surgery.

A comparison of three doses of a commercially prepared oral midazolam syrup in children.

UNLABELLED: Midazolam is widely used as a preanesthetic medication for children. Prior studies have used extemporaneous formulations to disguise the bitter taste of IV midazolam and to improve patient acceptance, but with unknown bioavailability. In this prospective, randomized, double-blinded study we examined the efficacy, safety, and taste acceptability of three doses (0.25, 0.5, and 1.0 mg/kg, up to a maximum of 20 mg) of commercially prepared Versed((R)) syrup (midazolam HCl) in children stratified by age (6 mo to <2 yr, 2 to <6 yr, and 6 to <16 yr). All children were ASA class I-III scheduled for elective surgery. Subjects were continuously observed and monitored with pulse oximetry. Ninety-five percent of patients accepted the syrup, and 97% demonstrated satisfactory sedation before induction. There was an apparent relationship between dose and onset of sedation and anxiolysis (P < 0.01). Eight-eight percent had satisfactory anxiety ratings at the time of attempted separation from parents, and 86% had satisfactory anxiety ratings at face mask application. The youngest age group recovered earlier than the two older age groups (P < 0.001). There was no relationship between midazolam dose and duration of postanesthesia care unit stay. Before induction, there were no episodes of desaturation, but there were two episodes of nausea and three episodes of emesis. At the time of induction, during anesthesia, and in the postanesthesia care unit, there were several adverse respiratory events. Oral midazolam syrup is effective for producing sedation and anxiolysis at a dose of 0.25 mg/kg, with minimal effects on respiration and oxygen saturation even when administered at doses as large as 1.0 mg/kg (maximum, 20 mg) as the sole sedating medication to healthy children in a supervised clinical setting. IMPLICATIONS: Commercially prepared oral midazolam syrup is effective in producing sedation and anxiolysis in doses as small as 0.25 mg/kg; there is a slightly faster onset with increasing the dose to 1.0 mg/kg. At all doses, 97% of patients demonstrated satisfactory sedation, whereas 86% demonstrated satisfactory anxiolysis when the face mask was applied.