Evaluation of I-Gel™ size 2 airway in different degrees of neck flexion in anesthetized children - a prospective, self-controlled trial

BACKGROUND

A previous study by our group demonstrated an increase in oropharyngeal leak pressures and a deterioration of ventilation in maximum neck flexion with the I-Gel^™ . To ascertain the optimal degree of neck flexion which increases OPLP without compromising ventilation we conducted a prospective self-controlled trial with the I-Gel^™ in different degrees of neck flexion in anesthetized paralyzed children.

METHODOLOGY

The I-gel^™ was inserted in 60 children undergoing inhalation induction with muscle paralysis for routine general anesthesia. Recordings of peak inspiratory pressures (PIP) at flexion of 15°, 30°, and 45° were taken as the primary outcome. Expired tidal volume, ventilation scoring, fiberoptic gradings, and OPLP in different degrees of flexion were recorded as secondary outcomes.

RESULTS

There was a significant increase in mean PIP in cm H₂ O at flexion 30° [13.3 (95% CI 12.8-13.8) cm H₂ O, P < 0.001] and 45° flexion (16.5 [15.9-17.1] cm H₂ O, P < 0.001) compared to neutral. A decrease in the expired tidal volume was seen at flexion of 30° (7.6 [7.3-7.8] cm H₂ O, P = 0.00) and 45° (7.6 [7.3-7.8] cm H₂ O, P = 0.00). There was deterioration of ventilation score, mean [range] at 30° flexion 2[0-3], and 45° flexion 1[0-3] compared to the neutral 3[2-3]. There was a significant increase in OPLP with an increase in degree of flexion.

CONCLUSION

We conclude that 15° neck flexion can safely be applied without compromising ventilation with the I-Gel^™ in anesthetized paralyzed children. However, Flexion of 30° or more warrants caution or the use of alternative devices like an endotracheal tube due to increase in PIP and worsening of ventilation score.

Comparative effectiveness of McCoy laryngoscope and CMAC(®) videolaryngoscope in simulated cervical spine injuries

Background:

Videolaryngoscopes are increasingly being used in potentially difficult airway. McCoy laryngoscope provides definitive advantage over conventional laryngoscopes in cervical spine patients. The aim of this study was to compare the performance of the CMAC^® videolaryngoscope with the McCoy Laryngoscope in patients with a cervical collar.

Material and Methods:

Sample size of at least 22 patients in each group was calculated using Intubation Difficulty Scale (IDS) score as the primary outcome. 60 American Society of Anesthesiologists I and II patients requiring tracheal intubation for elective surgery were randomly allocated into the McCoy group (n = 30) and the CMAC^® videolaryngoscope group (n = 30). Anesthesia was induced with fentanyl 2 mcg/kg, propofol 2-3 mg/kg and rocuronium 0.6 mg/kg. A rigid collar was applied to immobilize the cervical spine. Comparative data on the IDS scale, Cormack-Lehane (CL) laryngoscopic view, time taken for glottis visualization, time taken to pass endotracheal tube, total time to intubate, number of optimizing maneuvers and hemodynamic variables were recorded in the two groups.

Results:

IDS score was significantly less in the CMAC^® group compared to the McCoy group (median [interquartile range (IQR)], 1 [0-1] vs. 4 [3-6], P < 0.05). CMAC^® videolaryngoscope required significantly less time for glottic visualization with median (IQR), 5 (5-7) versus 14 (8-15), P = 0.000 in McCoy laryngoscope, 29 (96.7%) patients in the CMAC^® group had Modified CL Grade I compared with 16 (53.3%) patients in McCoy group. The hemodynamic variables, number of optimizing maneuvers and incidence of side effects were comparable in the two groups.

Conclusion:

CMAC^® videolaryngoscope forms an effective tool for the airway management of cervical spine patients with a cervical collar.

Evaluation of I-gel™ airway in different head and neck positions in anesthetized paralyzed children

BACKGROUND

Studies that have compared and quantified the oropharyngeal leak pressure (OPLP) and adequacy of ventilation with supraglottic airway devices in different head and neck positions have been done in adult populations. The effects of head-neck position changes on the functioning of I-gel(™) in pediatric population still remain unevaluated.

AIM

This study aimed to quantify the influence of different head and neck positions namely neutral, maximum flexion, and maximum extension on OPLP, ventilation scoring, and fiberoptic grading using I-gel(™) in anesthetized, paralyzed children.

METHODS

I-gel(™) was inserted in 30 paralyzed, anesthetized children scheduled for elective urological and orthopedic procedures. Anesthesia was induced with sevoflurane in oxygen. Atracurium was administered intravenously to facilitate neuromuscular relaxation. Recordings of OPLP in neutral, maximum flexion, and maximum extension were taken as primary outcome. Fiberoptic grading, insertion of ryle's tube and ventilation scoring were also measured in different head and neck positions as secondary outcomes.

RESULTS

The OPLP was significantly higher in flexion (27.6 ± 3.3 cm H2 O, P = 0.000) and lower in extension (19.6 ± 3.2 cm H2 O, P = 0.006) in comparison to the neutral position (23.2 ± 3.2 cm H2 O). There was a worsening of the fiberoptic view in flexion compared to neutral position (0/5/19/6 vs 5/21/4/0). The ventilation score was poorer (1 [0-3], P < 0.05) and peak inspiratory pressures higher in flexion (15.2 ± 1.4 cm H2 O, P = 0.000) compared to the neutral position (10.4 ± 1.6 cm H2 O).

CONCLUSION

Caution is warranted in pediatric patients while ventilating with I-gel(™) in extreme flexion of head and neck owing to poor ventilation despite increase in OPLP.

Mapping of yellow mosaic virus (YMV) resistance in soybean (Glycine max L. Merr.) through association mapping approach

Yellow Mosaic Virus (YMV) is a serious disease of soybean. Resistance to YMV was mapped in 180 soybean genotypes through association mapping approach using 121 simple sequence repeats (SSR) and four resistance gene analogue (RGA)-based markers. The association mapping population (AMP) (96 genotypes) and confirmation population (CP) (84 genotypes) was tested for resistance to YMV at hot-spot consecutively for 3 years (2007-2009). The genotypes exhibited significant variability for YMV resistance (P < 0.01). Molecular genotyping and population structure analysis with 'admixture' co-ancestry model detected seven optimal sub-populations in the AMP. Linkage disequilibrium (LD) between the markers extended up to 35 and 10 cM with r2 > 0.15, and >0.25, respectively. The 4 RGA-based markers showed no association with YMV resistance. Two SSR markers, Satt301 and GMHSP179 on chromosome 17 were found to be in significant LD with YMV resistance. Contingency Chi-square test confirmed the association (P < 0.01) and the utility of the markers was validated in the CP. It would pave the way for marker assisted selection for YMV resistance in soybean. This is the first report of its kind in soybean.

Population structure and association mapping studies for important agronomic traits in soybean

The present study was carried out with a set of 96 diverse soybean genotypes with the objectives of analysing the population structure and to identify molecular markers associated with important agronomic traits. Large phenotypic variability was observed for the agronomic traits under study indicating suitability of the genotypes for association studies. The maximum values for plant height, pods per plant, seeds per pod, 100-seed weight and seed yield per plant were approximately two and half to three times more than the minimum values for the genotypes. Seed yield per plant was found to be significantly correlated with pods per plant (r = 0.77), 100-seed weight (r = 0.35) and days to maturity (r = 0.23). The population structure studies depicted the presence of seven subpopulations which nearly corresponded with the source of geographical origin of the genotypes. Linkage disequilibrium (LD) between the linked markers decreased with the increased distance, and a substantial drop in LD decay values was observed between 30 and 35 cM. Genomewide marker-traits association analysis carried out using general linear (GLM) and mixed linear models (MLM) identified six genomic regions (two of them were common in both) on chromosomes 6, 7, 8, 13, 15 and 17, which were found to be significantly associated with various important traits viz., plant height, pods per plant, 100-seed weight, plant growth habit, average number of seeds per pod, days to 50% flowering and days to maturity. The phenotypic variation explained by these loci ranged from 6.09 to 13.18% and 4.25 to 9.01% in the GLM and MLM studies, respectively. In conclusion, association mapping (AM) in soybean could be a viable alternative to conventional QTL mapping approach.

Comparison of serum triglyceride levels with propofol in long chain triglyceride and propofol in medium and long chain triglyceride after short term anesthesia in pediatric patients

BACKGROUND

Significant increase in serum triglyceride (ST) concentration have been described in adult population after prolonged administration of propofol formulation containing long chain triglyceride (LCT). Though, medium chain triglyceride-LCT (MCT-LCT) propofol when compared with LCT propofol for long-term sedation in adults resulted in identical triglyceride levels, the elimination of triglyceride was faster in patients administered MCT-LCT propofol.

MATERIALS AND METHODS

A total of 40 children were randomized into two groups of 20 each; Group I were induced with 1% LCT propofol (3 mg/kg) and Group II with 1% medium and LCT propofol and maintained with descalating dose of 20.15 and 10 mg/kg/h at 10 min intervals. Blood samples for ST concentration were obtained before induction of anesthesia, at the end of propofol infusion and 4 h after terminating propofol infusion.

RESULTS

ST levels were raised significantly above the basal values in both the groups but the rise was significantly higher in Group I (P < 0.05). Four hours after stopping propofol infusion the triglyceride levels were similar to the basal values in Group II, whereas in Group I the values were significantly greater than the baseline (P < 0.05) as well as those of Group II (P < 0.05). No clinically significant adverse effect of hypertriglyceridemia was observed.

CONCLUSION

Even short term anesthesia with LCT and MCT-LCT propofol (1%) leads to elevated ST levels. The increase in ST levels is less with MCT-LCT propofol and elimination of triglyceride is also rapid after terminating MCT-LCT propofol infusion.

A dose-response study of caudal dexmedetomidine with ropivacaine in pediatric day care patients undergoing lower abdominal and perineal surgeries: a randomized controlled trial

OBJECTIVES

This randomized double-blind study was conducted to evaluate the analgesic efficacy and safety of addition of three different doses of dexmedetomidine in caudal ropivacaine compared with plain ropivacaine for postoperative analgesia in pediatric day care patients.

METHODS

Eighty children of American Society of Anesthesiologists grade I-II, aged 1-8 years, undergoing lower abdominal and perineal surgery were included. Children were randomly allocated into four groups. Group 1 received 0.2% plain ropivacaine 0.75 ml·kg(-1), while group 2, 3, and 4 received dexmedetomidine 0.5, 1.0, and 1.5 μg·kg(-1), respectively, along with 0.2% ropivacaine 0.75 ml·kg(-1). Anesthesia was induced and maintained with sevoflurane and 50% N2O in oxygen. Children were observed for postoperative pain, nausea-vomiting, agitation, sedation, and adverse effects. Rescue analgesia was provided with oral paracetamol.

RESULTS

Postoperative analgesia was significantly prolonged in all dexmedetomidine groups as compared to plain ropivacaine group (P < 0.001). All patients in the plain ropivacaine group required rescue analgesia within first 6 postoperative hours, while none in the other three groups. None of the patients showed delayed anesthetic emergence. Four patients in the plain ropivacaine group developed agitation, while none in the dexmedetomidine groups. Patients receiving dexmedetomidine 1.5 μg·kg(-1) were more sedated as compared to the other groups (P < 0.01), but it did not delay discharge of the patients.

CONCLUSIONS

All three doses of caudal dexmedetomidine appear to be effective for preventing postoperative pain in pediatric day care patients. Caudal dexmedetomidine used in these doses seems to be safe for day care surgery.