Intramuscular ketamine for prevention of postanesthesia shivering in children

OBJECTIVE: To compare the effects of intramuscular ketamine with pethidine and placebo on post operative shivering in children undergoing tonsillectomy. METHODS: A prospective randomized double-blind study was conducted at King Abdulaziz Naval Base Hospital, Jubail, Kingdom of Saudi Arabia, from November 2006 to October 2007. One hundred and twenty children (American Society of Anesthesiologists Grade 1, aged 5-12 years) were enrolled. Children were randomly allocated to receive ketamine 1 mg/kg (group K, n=40), or pethidine 0.5 mg/kg (group P, n=40), or normal saline (group S, n=40) intramuscularly just after induction of general anesthesia. Hemodynamic parameters, oxygen saturation and tympanic temperature were measured and recorded before induction of anesthesia and at regular intervals thereafter. An investigator blinded to the treatment group, graded postoperative shivering using a 5 point scale. RESULTS: The number of patients shivering on arrival to the recovery room and at 10 and 20 minutes after operation were significantly less in groups K (1,1,1) than in group S (19,12,17). No patient that received pethidine shivered. The time to first analgesic requirement in group S was shorter than groups K and P (p=0.001). CONCLUSION: The study indicates that the use of a prophylactic low dose ketamine was found to be effective in preventing post anesthesia shivering in children undergoing tonsillectomy. Ketamine may have at least theoretical advantages over pethidine as regard respiratory depression, nausea, and vomiting.     

Pim-1 kinase antagonizes aspects of myocardial hypertrophy and compensation to pathological pressure overload

Pim-1 kinase exerts potent cardioprotective effects in the myocardium downstream of AKT, but the participation of Pim-1 in cardiac hypertrophy requires investigation. Cardiac-specific expression of Pim-1 (Pim-WT) or the dominant-negative mutant of Pim-1 (Pim-DN) in transgenic mice together with adenoviral-mediated overexpression of these Pim-1 constructs was used to delineate the role of Pim-1 in hypertrophy. Transgenic overexpression of Pim-1 protects mice from pressure-overload-induced hypertrophy relative to wild-type controls as evidenced by improved hemodynamic function, decreased apoptosis, increases in antihypertrophic proteins, smaller myocyte size, and inhibition of hypertrophic signaling after challenge. Similarly, Pim-1 overexpression in neonatal rat cardiomyocyte cultures inhibits hypertrophy induced by endothelin-1. On the cellular level, hearts of Pim-WT mice show enhanced incorporation of BrdU into myocytes and a hypercellular phenotype compared to wild-type controls after hypertrophic challenge. In comparison, transgenic overexpression of Pim-DN leads to dilated cardiomyopathy characterized by increased apoptosis, fibrosis, and severely depressed cardiac function. Furthermore, overexpression of Pim-DN leads to reduced contractility as evidenced by reduced Ca²⁺ transient amplitude and decreased percentage of cell shortening in isolated myocytes. These data support a pivotal role for Pim-1 in modulation of hypertrophy by impacting responses on molecular, cellular, and organ levels.     

Transport of Schisandra chinensis extract and its biologically-active constituents across Caco-2 cell monolayers - an in-vitro model of intestinal transport

We have determined the intestinal transport of Schisandra chinensis extract and its lignans (gomisin A, gomisin N and schisandrin C) in the Caco-2 cell monolayer model. The transport across monolayers was examined for 2 h in absorptive and secretory directions. Quantitation of lignans was performed by HPLC. Out of the three lignans, gomisin A exhibited bi-directional transport, with P(app) values in the range of 25-29 x 10(-6) cm s(-1), indicating a passive diffusion. Gomisin N, mixture and Schisandra extract displayed a higher transport in the secretory direction with efflux ratios in the range of 2.2-5.2. The efflux was decreased in the presence of inhibitors of multidrug resistance protein (MRP) transporter (MK-571) and P-glycoprotein (verapamil) indicating a possible involvement of an efflux pump and MRP in the transport of Schisandra lignans. Poor transport of schisandrin C was observed which could not be quantitated. The permeability of gomisin A in the isolated form was significantly different compared with the mixture or extract.     

Changes in retinal nerve fibre layer, optic nerve head morphology, and visual field after acute primary angle closure

Aims/Purpose

To determine and correlate the long-term changes in retinal nerve fibre layer (RNFL) thickness, optic nerve head (ONH) morphology, and visual fields after a single episode of acute primary angle closure (APAC).

Methods

This was a cross-sectional comparative study of patients at National University Hospital (Singapore) from 2000 to 2006 after an episode of unilateral APAC. The peripapillary and macular RNFL were measured using Stratus optical coherence tomography (OCT) and ONH configuration was assessed using Heidelberg Retina Tomography (HRT)-III. Humphrey perimetry was also performed, and the presence of disc pallor was noted. APAC eyes were compared with fellow eyes as matched controls.

Results

Twenty-five patients were assessed at a median of 33 months (range, 11–85 months) after APAC. OCT showed that there was a reduction in the peripapillary and outer macular RNFL thickness in APAC eyes compared with controls. Humphrey perimetry revealed significantly reduced mean deviation (P=0.006) and increased pattern standard deviation (P=0.045) in APAC eyes compared with controls. HRT-III showed no difference in mean rim area, rim volume, or cup–disc ratio between APAC eyes and controls. Disc pallor was present in nine APAC eyes (36%) but was absent in fellow eyes (P=0.002), and was associated with peripapillary RNFL thinning, visual field loss, and an increased interval between the onset of symptoms and normalization of intraocular pressure (P=0.023).

Conclusion

APAC results in peripapillary and outer macular RNFL loss, visual field defects, and optic disc pallor, even in cases in which the ONH configuration remains unchanged.     

Intracuff pressure during one-lung ventilation in infants and children

ObjectiveWe prospectively evaluated intracuff pressure (IP) during one-lung ventilation (OLV) to characterize potential risk associated with overinflation of the cuff used for OLV.DesignProspective observational study over a 2-year period, in infants and children undergoing thoracic surgery. The IPs of the tracheal and bronchial balloon were measured using a manometer and compared to a previously recommended threshold of 30 cmH2O. Data were compared by the device type used to achieve OLV.SettingFreestanding tertiary-care pediatric hospital.ParticipantsPatients ≤ 18 years of age undergoing thoracic procedures requiring OLV.InterventionsMeasurement of IP.Measurements and main resultsThirty patients were enrolled (age 5 months–18 years) with a median weight of 28 kg. Median tracheal and bronchial IPs were 32 cmH2O (range: 11, 90) and 44 cmH2O (range: 10, 100), respectively. The tracheal and bronchial IPs exceeded 30 cmH2O in 13 of 20 patients (65%) and 21 of 30 patients (70%), respectively.ConclusionsIP was high and in excess of recommended levels in most children undergoing OLV. Continuous monitoring of IP may be indicated during OLV to address the risks involved and ensure the prevention of complications related to high IP.Type of studyProspective comparative study.Level of evidenceLevel II.