A comparative study to evaluate the cervical spine movements during laryngoscopy using Macintosh and Airtraq laryngoscopes.

Background and Aim: Intubation with Macintosh requires flexing the lower cervical spine and extending the atlanto-occipital joint to create a "line of sight." Primary aim of study was to compare the extent of cervical spine movement during laryngoscopy using conventional Macintosh laryngoscope and Airtraq. Material and Methods: A total of 25 patients of either sex between the age group of 18 and 60 years, having American Society of Anesthesiologists (ASA) physical status of Grade-I and Grade-II, scheduled for elective surgery under image control requiring general anesthesia and intubation were enrolled. A baseline image of the lateral cervical spine including the first four cervical vertebrae was taken by an image intensifier. After administration of general anesthesia, laryngoscopy was first performed using a Macintosh laryngoscope and a second X-ray image of the lateral cervical spine was taken. The second laryngoscopy using a Airtraq laryngoscope was done and the third image of the lateral cervical spine was taken. Angles between occiput and C1; C1 and C2; C2 and C3; C3 and C4; and occiput and C4 were calculated. Atlanto-occipital distance (AOD) was calculated as the distance between occiput and C1. Results: Macintosh showed greater cervical movement as compared with Airtraq but a significant difference in the movement was observed at C2-C3 and C0-C4. Baseline mean AOD was 2.21 ± 1.25 mm, after Macintosh and Airtraq laryngoscopy was found to be 1.13 ± 0.60 and 1.6 ± 0.78 mm, respectively, and was found to be significant (P < 0.05). Conclusion: We conclude that Airtraq allows intubation with less movement of the upper cervical spine makes Airtraq preferred equipment for intubation in patients with a potential cervical spine injury.

A Prospective Study to Evaluate the Clinical and Diffusion Tensor Imaging (DTI) Correlation in Patients with Lumbar Disc Herniation with Radiculopathy.

Introduction: Conventional magnetic resonance imaging findings frequently do not correlate with the symptoms of lumbar disc herniation (LDH). Diffusion-weighted imaging can reveal important details about the microstructure of tissues. This study assessed the role of diffusion-weighted imaging (DTI) in LDH with radiculopathy and explored the relationship between DTI values and clinical scores. Methods: Forty-five patients with LDH with radiculopathy were evaluated via DTI at the intraspinal (IS), intraforaminal (IF), and extraforaminal (EF) levels. A visual analog scale (VAS) was used for low back and leg pain. The Japanese Orthopaedic Association (JOA) scoring system, Oswestry Disability Index (ODI), and Roland-Morris Disability Questionnaire (RMDQ) were used for functional evaluation. Results: There was a statistically significantly (p<0.05) difference between the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values on the affected side compared with those on contralateral normal side. The VAS score had a weak positive correlation with RMDQ score (r=0.279, P=0.050). The JOA score had a moderate negative correlation with RMDQ score (r=-0.428, P=0.002), whereas the ODI score had a moderate positive correlation with RMDQ score (r=0.554, P<0.001). There was a moderate positive correlation between ADC values at the IF level and the RMDQ score on the affected side (r=0.310, P=0.029). There was no correlation between FA values and JOA score. ODI had a significantly positive correlation with the contralateral normal side FA values at the IF (r=0.399, P=0.015), EF (r=0.368, P=0.008) and IS (r=0.343, P=0.015) levels. RMDQ had a weak positive correlation with the contralateral normal side FA values at the IF (r=0.311, P=0.028), IS (r=0.297, P=0.036) and EF (r=0.297, P=0.036) levels. Conclusions: The decrease in FA values and the increase in ADC values are useful markers of compression. ADC correlates well with the patient's neurological symptoms and functional status. Conversely, FA correlates well with the patient's neurological symptoms, but is not correlated well with the functional status.

Do MRI-derived muscle moment-arms in patients with chronic low back pain differ from healthy individuals? A comparative study.

OBJECTIVES: The present study aimed to estimate the trunk muscles moment-arms in low back pain (LBP) patients and compare this data to those of healthy individuals. This research further explored whether the difference of the moment-arms between these two is a contributing factor to LBP. METHODOLOGY: Fifty patients with CLBP (group A) and 25 healthy controls (group B) were enrolled. All participants were subjected to magnetic resonance imaging of lumbar spine. Muscle moment-arms were estimated on a T2W axial section parallel to the disc. RESULTS: There was statistically significant differences (p < 0.05) in the sagittal plane moment-arms at L1-L2 for right erector spinae (ES), bilateral psoas and rectus abdominis (RA), right quadratus lumborum (QL), and left obliques; bilateral ES, QL, RA, and right psoas at L2-L3; bilateral QL, RA, and obliques at L3-L4; bilateral RA and obliques at L4-L5; and bilateral psoas, RA, and obliques at L5-S1. There was no statistically significant difference (p < 0.05) in the coronal plane moment-arms except for left ES and QL at L1-L2; left QL and right RA at L3-L4; right RA and obliques at L4-L5; and bilateral ES and right RA at L5-S1. CONCLUSIONS: There was a significant difference in muscle moment-arms of the lumbar spine's prime stabilizer (psoas) and primary locomotors (rectus abdominis and obliques) between LBP patients and healthy individuals. This difference in the moment-arms leads to altered compressive forces at intervertebral discs and may be one of the risk factors for LBP.

Intra-operative and early post-operative prediction of cardiac surgery-associated acute kidney injury: Urinary oxygen tension compared with plasma and urinary biomarkers.

Acute kidney injury (AKI) is a common and serious post-operative complication of cardiac surgery. The value of a predictive biomarker is determined not only by its predictive efficacy, but also by how early this prediction can be made. For a biomarker of cardiac surgery-associated AKI, this is ideally during the intra-operative period. Therefore, in 82 adult patients undergoing cardiac surgery requiring cardiopulmonary bypass (CPB), we prospectively compared the predictive efficacy of various blood and urinary biomarkers with that of continuous measurement of urinary oxygen tension (UPO2 ) at pre-determined intra- and post-operative time-points. None of the blood or urine biomarkers we studied showed predictive efficacy for post-operative AKI when measured intra-operatively. When treated as a binary variable (≤ or > median for the whole cohort), the earliest excess risk of AKI was predicted by an increase in urinary neutrophil gelatinase-associated lipocalin (NGAL) at 3 h after entry into the intensive care unit (odds ratio [95% confidence limits], 2.86 [1.14-7.21], p = 0.03). Corresponding time-points were 6 h for serum creatinine (3.59 [1.40-9.20], p = 0.008), and 24 h for plasma NGAL (4.54 [1.73-11.90], p = 0.002) and serum cystatin C (6.38 [2.35-17.27], p = 0.001). In contrast, indices of intra-operative urinary hypoxia predicted AKI after weaning from CPB, and in the case of a fall in UPO2 to ≤10 mmHg, during the rewarming phase of CPB (3.00 [1.19-7.56], p = 0.02). We conclude that continuous measurement of UPO2 predicts AKI earlier than plasma or urinary NGAL, serum cystatin C, or early post-operative changes in serum creatinine.

Blunted natriuretic response to saline loading in sheep with hypertensive kidney disease following radiofrequency catheter-based renal denervation.

Renal sympathetic nerves contribute to renal excretory function during volume expansion. We hypothesized that intact renal innervation is required for excretion of a fluid/electrolyte load in hypertensive chronic kidney disease (CKD) and normotensive healthy settings. Blood pressure, kidney hemodynamic and excretory response to 180 min of isotonic saline loading (0.13 ml/kg/min) were examined in female normotensive (control) and hypertensive CKD sheep at 2 and 11 months after sham (control-intact, CKD-intact) or radiofrequency catheter-based RDN (control-RDN, CKD-RDN) procedure. Basal blood pressure was ~ 7 to 9 mmHg lower at 2, and 11 months in CKD-RDN compared with CKD-intact sheep. Saline loading did not alter glomerular filtration rate in any group. At 2 months, in response to saline loading, total urine and sodium excretion were ~ 40 to 50% less, in control-RDN and CKD-RDN than intact groups. At 11 months, the natriuretic and diuretic response to saline loading were similar between control-intact, control-RDN and CKD-intact groups but sodium excretion was ~ 42% less in CKD-RDN compared with CKD-intact at this time-point. These findings indicate that chronic withdrawal of basal renal sympathetic activity impairs fluid/electrolyte excretion during volume expansion. Clinically, a reduced ability to excrete a saline load following RDN may contribute to disturbances in body fluid balance in hypertensive CKD.