Tracheal intubation following training with the GlideScope compared to direct laryngoscopy.

SUMMARY: Tracheal intubation using direct laryngoscopy has a high failure rate when performed by untrained medical personnel. This study compares tracheal intubation following direct laryngoscopy by inexperienced medical students when initially trained by using either the GlideScope, a video assisted laryngoscope, or a rigid (Macintosh) laryngoscope. Forty-two medical students with no previous experience in tracheal intubation were randomly divided into two equal groups to receive training with the GlideScope or with direct laryngoscopy. Subsequently, each medical student performed three consecutive intubations on patients with normal airways that were observed by a anaesthetist who was blinded to the training method. The rates of successful intubation were significantly higher in the Glidescope group after the first (48%), second (62%), and third (81%) intubations compared with the Macintosh group (14%, 14% and 33%; p = 0.043, 0.004 and 0.004, respectively). The mean (SD) times for the first, second, and third successful tracheal intubations were significantly shorter in the Glidescope group (59.3 (4.4) s, 56.6 (7.1) s and 50.1 (4.0) s) than the Macintosh group (70.7 (7.5) s, 73.7 (7.3) s and 67.6 (2.0) s; p = 0.006, 0.003 and 0.0001, respectively). Training with a video-assisted device such as the GlideScope improves the success rate and time for tracheal intubation in patients with normal airways when this is performed by inexperienced individuals following a short training programme.

Addition of ketamine to propofol for initiation of procedural anesthesia in children reduces propofol consumption and preserves hemodynamic stability.

BACKGROUND: There is no ideal anesthesia protocol to perform short invasive procedures in pediatric oncology. The combination of propofol and ketamine may offer advantages over propofol alone. METHODS: In a prospective, randomized, double-blind study, we analyzed 63 consecutive procedures performed in 47 oncology children. All patients received 1 mug/kg fentanyl, followed by propofol 1 mg/kg in group P (n=33) or propofol 0.5 mg/kg and ketamine 0.5 mg/kg in group PK (n=30) for the initiation of anesthesia. The need for supplementation with propofol and/or fentanyl to maintain an adequate level of anesthesia was recorded. The hemodynamic and respiratory profile, recovery time and the occurrence of side effects were compared. RESULTS: Significantly more children required propofol (100% vs. 83.3%) and fentanyl (75.5% vs. 43.3%) rescue doses, and developed hypotension (63.6% vs. 23.4%) and bradycardia (48.5 vs. 23.4%) in group P compared with group PK, with a comparable incidence of respiratory adverse events and recovery times. However, 40% of children in group PK were agitated following recovery compared with 6% in group P. CONCLUSIONS: The combination of propofol and ketamine for invasive procedures in pediatric oncology resulted in reduced propofol and fentanyl consumption and preserved hemodynamic stability, but more children in the combination group recovered with agitation.

Supplementation of pre-oxygenation in morbidly obese patients using nasopharyngeal oxygen insufflation.

During apnoea following induction of anaesthesia, morbidly obese patients may suffer a rapid decrease in oxygen saturation. This study compares pre-oxygenation alone with pre-oxygenation followed by nasopharyngeal oxygen insufflation on the onset of desaturation occurring during the subsequent apnoea. A randomised controlled trial was performed in 34 morbidly obese patients undergoing gastric bypass or gastric band surgery. Seventeen patients received nasopharyngeal oxygen supplementation following pre-oxygenation (Study group, body mass index = 41.8 (6.9) kg.m(-2)), and the other 17 patients received pre-oxygenation alone (Control group, body mass index = 42.7 (5.4) kg.m(-2)). Time from the onset of apnoea until S(p)o(2) fell to 95% was compared between the two groups with a cut-off of 4 min. In the control group, the S(p)o(2) fell from 100% to 95% during the subsequent apnoea in 145 (27) s, with a significantly negative correlation (r(2) = 0.66, p < 0.05) between the time to desaturation to 95% and the body mass index. In the study group, the S(p)o(2) was maintained in 16 of 17 patients at 100% for 4 min when apnoea was terminated. In conclusion, nasopharyngeal oxygen insufflation following pre-oxygenation in morbidly obese patients delays the onset of oxyhaemoglobin desaturation during the subsequent apnoea.

Effect of low-dose dexmedetomidine or clonidine on the characteristics of bupivacaine spinal block.

BACKGROUND: The purpose of this study was to compare the onset and duration of sensory and motor block, as well as the hemodynamic changes and level of sedation, following intrathecal bupivacaine supplemented with either dexmedetomidine or clonidine. METHODS: In a prospective, double-blind study, 60 patients undergoing transurethral resection of prostate or bladder tumor under spinal anesthesia were randomly allocated to one of three groups. Group B received 12 mg of hyperbaric bupivacaine, group D received 12 mg of bupivacaine supplemented with 3 microg of dexmedetomidine and group C received 12 mg of bupivacaine supplemented with 30 microg of clonidine. The onset times to reach peak sensory and motor levels, and the sensory and motor regression times, were recorded. Hemodynamic changes and the level of sedation were also recorded. RESULTS: Patients in groups D and C had a significantly shorter onset time of motor block and significantly longer sensory and motor regression times than patients in group B. The mean time of sensory regression to the S1 segment was 303 +/- 75 min in group D, 272 +/- 38 min in group C and 190 +/- 48 min in group B (B vs. D and B vs. C, P < 0.001). The regression of motor block to Bromage 0 was 250 +/- 76 min in group D, 216 +/- 35 min in group C and 163 +/- 47 min in group B (B vs. D and B vs. C, P < 0.001). The onset and regression times were not significantly different between groups D and C. The mean arterial pressure, heart rate and level of sedation were similar in the three groups intra-operatively and post-operatively. CONCLUSIONS: Dexmedetomidine (3 microg) or clonidine (30 microg), when added to intrathecal bupivacaine, produces a similar prolongation in the duration of the motor and sensory block with preserved hemodynamic stability and lack of sedation.

An unusual case of hyperkalaemia-induced cardiac arrest in a paediatric patient during transfusion of a 'fresh' 6-day-old blood unit.

A well-recognized complication of the transfusion of red blood cells (RBCs) is hyperkalaemia. This occurs in paediatric or adult patients receiving massive transfusion and can lead to cardiac arrest. Hyperkalaemia may follow the transfusion of 'stored' RBCs and/or haemolysed units, and depends on the quantity and rate of transfusion. We report on an unusual case of hyperkalaemia-induced cardiac arrest during transfusion of a 'fresh' blood unit. A 62-day-old baby girl was scheduled for a construction of a Blalock-Taussig shunt, after the completion of anastomosis, and upon release of vascular control, there was bleeding at the anastomotic site that was controlled with a suture placement. To compensate for the blood loss, a stat order was given for a push of 120 mL of RBCs over 10 min through the inferior vena cava central line. The blood unit was 6 days old and had been gamma-irradiated 48 h earlier. Shortly after the transfusion, the patient's electrocardiogram showed changes typical of hyperkalaemia; she then went into cardiac asystole. The blood unit potassium concentration was 55.3 mmol L-1, which flushed the atrioventricular node during transfusion. This is the first report of a high potassium level found in a 'fresh', less than 7 days old, nonhaemolysed RBC blood unit. The high concentration of potassium in this unit seems to be due to accelerated alterations of the RBC sodium/potassium adenosine triphosphatase pump (Na+/K+ pump), resulting in the release of intracellular potassium. This early and severe alteration of the pump and the unusually high potassium level may be due to as yet unexplained causes, warranting awareness, future investigation and routine saline washing of 'fresh' RBCs for paediatric patients who are candidates for central line transfusion.