Low Pressure Group Research Articles

Relationship Between Trajectories of Trunk Fat Mass Development in Adolescence and Cardiometabolic Risk in Young Adulthood

To examine developmental trajectories of trunk fat mass (FM) growth of individuals categorized as either low or high for cardiometabolic risk at 26 years, a total of 55 males and 76 females from the Saskatchewan Pediatric Bone Mineral Accrual Study (1991-2007) were assessed from adolescence (11.5 ± 1.8 years) to young adulthood (26.2 ± 2.2 years) (median of 11 visits per individual) and had a measure of cardiometabolic risk in young adulthood. Participants were categorized as low or high for blood pressure and cardiometabolic risk as adults using a sex-specific median split of continuous standardized risk scores. Individual trunk FM trajectories of participants in each risk group were analyzed using multilevel random effects models. Males and females in the high blood pressure group had significantly steeper (accelerated) trajectories of trunk FM development (0.61 ± 0.14 and 0.52 ± 0.10log g, respectively) than those in the low blood pressure group for females in the high cardiometabolic risk group trajectory of trunk FM was significantly steeper (0.52 ± 0.10log g) than those females in the low cardiometabolic risk group. Dietary fat was positively related (0.01 ± 0.003g/1,000kcal) and physical activity negatively related (-0.16 ± 0.05 physical activity score) to trunk FM development in males. Young adults with high cardiometabolic risk, compared to low, have greater trunk FM as early as 8 years of age, which supports the need for early intervention.

Impact of today's media on university student's body image in Pakistan: a conservative, developing country's perspective

BackgroundLiving in a world greatly controlled by mass media makes it impossible to escape its pervading influence. As media in Pakistan has been free in the true sense of the word for only a few years, its impact on individuals is yet to be assessed. Our study aims to be the first to look at the effect media has on the body image of university students in a conservative, developing country like Pakistan. Also, we introduced the novel concept of body image dissatisfaction as being both negative and positive.MethodsA cross-sectional study was conducted among 7 private universities over a period of two weeks in the city of Karachi, Pakistan's largest and most populous city. Convenience sampling was used to select both male and female undergraduate students aged between 18 and 25 and a sample size of 783 was calculated.ResultsOf the 784 final respondents, 376 (48%) were males and 408 (52%) females. The mean age of males was 20.77 (+/- 1.85) years and females was 20.38 (+/- 1.63) years. Out of these, 358 (45.6%) respondents had a positive BID (body image dissatisfaction) score while 426 (54.4%) had a negative BID score. Of the respondents who had positive BID scores, 93 (24.7%) were male and 265 (65.0%) were female. Of the respondents with a negative BID score, 283 (75.3%) were male and 143 (35.0%) were female. The results for BID vs. media exposure were similar in both high and low peer pressure groups. Low media exposure meant positive BID scores and vice versa in both groups (p < 0.0001) showing a statistically significant association between high media exposure and negative body image dissatisfaction. Finally, we looked at the association between gender and image dissatisfaction. Again a statistically significant association was found between positive body image dissatisfaction and female gender and negative body image dissatisfaction and male gender (p < 0.0001).ConclusionsOur study confirmed the tendency of the media to have an overall negative effect on individuals' body image. A striking feature of our study, however, was the finding that negative body image dissatisfaction was found to be more prevalent in males as compared to females. Likewise, positive BID scores were more prevalent amongst females.

Renal preservation in children with neurogenic bladder–sphincter dysfunction followed in a national program

PurposeNeurogenic bladder–sphincter dysfunction (NBSD) constitutes the major reason for morbidity in children with spina bifida. The aim of this study was to identify risk factors for renal damage in children with NBSD followed according to the Swedish national guidelines. Materials and MethodsRecords and cystometries from 6 to 16 years (median 11) follow up of 41 consecutive children born 1993–2003 with NBSD were evaluated. The children were divided into a high pressure group (baseline pressure above 30 cmH2O at maximal clean intermittent catheterization volume in at least two cystometries) and a low pressure group. Most children (34/41) were followed from birth. ResultsAlthough renal scarring on DMSA-scintigraphy was found in 5/41 children, all but one had normal renal function. Two already had renal scars on entering the follow-up program at age 2.5 and 3 years. Renal scarring was more frequent in the high pressure group (P < 0.01). Most children with renal scars (4/5) had a combination of low compliant bladder and insufficient compliance with treatment and follow up. ConclusionHigh baseline pressure is confirmed as a risk factor that, in combination with complex social issues, creates a demanding situation for families and professionals. A structured early follow up with treatment compliance effectively prevents renal damage.

The effect of blood pressure on cerebral outcome in a rat model of cerebral air embolism during cardiopulmonary bypass

Higher mean arterial pressure during cardiopulmonary bypass may improve cerebral outcome associated with cerebral air embolism by increasing emboli clearance and collateral flow to salvage the ischemic penumbra. However, this may come at the expense of increased delivery of embolic load. This study was designed to investigate the influence of mean arterial pressures on cerebral functional and histologic outcome after cerebral air embolism during cardiopulmonary bypass in an established rat model. Male Sprague-Dawley rats were exposed to 90 minutes of normothermic cardiopulmonary bypass with 10 cerebral air embolisms (0.3 μL/bolus) injected repetitively. Rats were randomized to 3 groups (n=10, each) that differed in mean arterial pressure management during cardiopulmonary bypass: 50 mm Hg (low mean arterial pressure), 60 to 70 mm Hg (standard mean arterial pressure), and 80 mm Hg (high mean arterial pressure). Neurologic score was assessed on postoperative days 3 and 7 when cerebral infarct volumes were determined. Cognitive function was determined with the Morris water maze test beginning on postoperative day 3 and continuing to postoperative day 7. Neurologic score was better in high and standard mean arterial pressure groups versus low mean arterial pressure groups. High mean arterial pressure resulted in shorter water maze latencies compared with standard and low mean arterial pressure on postoperative days 6 and 7. Total infarct volume and number of infarct areas were not different among groups. The use of higher mean arterial pressure during cardiopulmonary bypass in a rat model of cerebral air embolism conveyed beneficial effects on functional cerebral outcome with no apparent disadvantage of increased delivery of embolic load. Maintaining higher perfusion pressures in situations of increased cerebral embolic load may be considered as a collateral therapeutic strategy.

The composite Archaean grey gneisses: Petrological significance, and evidence for a non-unique tectonic setting for Archaean crustal growth

The geodynamic context of formation of the Archaean continental crust is a matter of debate. The crust is largely made of grey gneiss complexes, a composite rock assemblage dominated by granitoids that are generally regarded as belonging to the TTG (tonalite–trondhjemite–granodiorite) series. Using a large database of published TTG and grey gneiss compositions, it is possible to show that the granitoids forming grey gneiss complexes actually belong to at least four main geochemical groups: (i) a potassic component made of granodiorites and formed by melting of existing crustal lithologies; and (ii) three sodic groups (TTG proper) that comprise low, medium and high pressure groups. The geochemistry of the low pressure group is consistent with derivation from a plagioclase and garnet–amphibolite; the medium pressure group was formed in equilibrium with a garnet-rich, plagioclase-poor amphibolite, whereas the high pressure group derived from a rutile-bearing eclogite. As the temperature of melting of metamafic rocks is largely independent from pressure, this corresponds to melting along a range of contrasting geothermal gradients, in turn reflecting a range of tectonic sites for the formation of the Archaean continental crust.

Effect of different pressure magnitudes on hypertrophic scar in a Chinese population

Introduction This study aimed to investigate the effect of different pressure magnitudes on treatment outcomes of hypertrophic scars, and determine pressure loss over time. Methods A randomized clinical trial was adopted. 53 hypertrophic scar samples from 17 Chinese participants were recruited and randomly assigned into a high pressure group (20–25 mmHg) and low pressure group (10–15 mmHg) for a five-month intervention program. The scars were assessed objectively before intervention and monthly after intervention for thickness, color (redness, yellowness and lightness) and scar pliability. Pressure magnitude at each assessment was also measured. Two-way repeated ANOVA was used to compare for differences between groups. Results The results showed that both levels of pressure produced reduction in scar thickness and redness, but the improvement in the high pressure group was statistically better than that of the counterpart (both p < 0.05). Monthly pressure measurement revealed that pressure loss in the high pressure group was more severe. However, no major changes in other color parameters and pliability were observed for both the groups. Conclusion High pressure was demonstrated to be more effective for scar management, but it was also more prone to higher pressure loss. Pressure therapy integrated with regular monitoring of the interface pressure is suggested to improve its therapeutic efficacy.

Pretreatment with atorvastatin attenuates lung injury caused by high-stretch mechanical ventilation in an isolated rabbit lung model

We hypothesized that pretreatment with atorvastatin improves alveolar capillary permeability and hemodynamics and, thus, confers protection against lung injury caused by high-stretch mechanical ventilation. Twenty-four isolated sets of normal rabbit lungs were utilized. Treated animals received atorvastatin (20 mg/kg body weight/day by mouth) for 3 days before surgery. Lungs were perfused constantly (300 mL/min) and ventilated for 1 hr with pressure-control ventilation at either 23 (high pressure; resulting in tidal volume approximately 22 mL/kg) or 11 (low pressure; tidal volume approximately 10 mL/kg) cm H2O peak inspiratory pressure and positive end-expiratory pressure of 3 cm H2O. Four groups were examined: high pressure-no statin, high pressure-statin pretreatment, low pressure-no statin, and low pressure-statin pretreatment. The high-pressure-no statin group sustained more damage than the low-pressure groups. In high-pressure groups, lungs of statin-pretreated vs. no statin-pretreated animals sustained a significantly lower increase in ultrafiltration coefficient (an accurate marker of alveolar capillary permeability; high-pressure-statin pretreatment vs. high-pressure-no statin, -0.013 +/- 0.017 g/min/mm Hg/100g vs. 1.723 +/- 0.495 g/min/mm Hg/100g; p < .001), lower weight gain (i.e., less edema formation; 4.62 +/- 1.50 grams vs. 17.75 +/- 4.71 grams; p = .005), improved hemodynamics (i.e., lower increase in mean pulmonary artery pressure; 0.56 +/- 0.51 mm Hg vs. 5.62 +/- 1.52 mm Hg; p = .04), lower protein concentration in bronchoalveolar lavage fluid (p < .001), and fewer histologic lesions (p = .013). Apoptosis of lung parenchyma cells was not different (p = .97). There was no difference between low-pressure-statin pretreatment and low-pressure-no statin groups regarding these outcomes. In this model, atorvastatin improves alveolar capillary permeability and hemodynamics and, thus, attenuates lung injury caused by high-stretch mechanical ventilation.

Manofluorographic and functional outcomes after endoscopic laser cricopharyngeal myotomy for cricopharyngeal bar

Objective To investigate the manofluorographic and functional outcomes after endoscopic laser cricopharyngeal myotomy (ELCPM) for cricopharyngeal (CP) bar. Study Design Case series with chart review. Setting Academic medical center. Subjects and Methods Review of patients undergoing ELCPM between 2001 and 2007 was undertaken to determine the demographic, clinical, and manofluorographic findings before and six months after surgery. Two groups were established according to pharyngeal driving pressures: normal pressure group (> 55 mm Hg) and low pressure group (< 55 mm Hg). Results Fourteen patients underwent ELCPM for CP bar without a concomitant head and neck or Zenker's procedure. There were no major surgical complications. All 14 patients improved at least one stage on the Functional Outcome Swallowing Scale (FOSS) after surgery. There was a statistically significant decrease in the FOSS stages after surgery. Videofluoroscopy demonstrated a significant postoperative increase in the mean cross-sectional CP opening (CP-area) from 32.75 to 123.52 mm 2. Manofluorographic pressure recordings showed a significant postoperative decrease in the intrabolus pressure gradient across the cricopharyngeal region (IB-Gra) from 25.44 to 13.22 mm Hg. Despite significant overall results, the change in the IB-Gra showed no difference between the patient groups. Conclusion Subjective (FOSS) and objective manofluorographic (CP-area, IB-Gra) improvement in CP bar patients occurred after ELCPM. We suggest IB-Gra as a reliable objective indicator for patients who might benefit from ELCPM and as an appropriate parameter for follow-up after surgery. However, continued research on a larger patient population is required to enhance our understanding of CP bar and predictors of outcome after treatment of CP bar dysphagia.

Low Blood Pressure and Depressive Symptoms among Chinese Older Subjects: A Population-based Study

Background The relationships between blood pressure and depression are unclear. There are inconsistent reports of an association between low blood pressure and depressive symptoms. Methods In a population-based sample of 2611 Chinese older adults aged 55 years and above, including participants with treated (n = 1088), untreated (n = 545), or no hypertension (n = 978), depressive symptoms were determined by the 15-item Geriatric Depression Scale (≥5), and current systolic blood pressure and diastolic blood pressure measurements were used to classify participants into high, normal, and low blood pressure groups. Estimates of association were adjusted for confounding by use of antihypertensive and depressogenic drugs and other covariables in hierarchical regression analyses. Results Systolic blood pressure and diastolic blood pressure were negatively associated with Geriatric Depression Scale scores, independent of other variables. Low systolic blood pressure (odds ratio [OR] 1.54; 95% confidence interval [CI], 1.07-2.22), low diastolic blood pressure (OR 1.67; 95% CI, 0.98-2.85), and low systolic blood pressure or diastolic blood pressure (or both) (OR 1.55; 95% CI, 1.10-2.19) were independently associated with depressive symptoms. The associations with depressive symptoms were particularly observed for low systolic blood pressure (OR 2.13; 95% CI, 1.13-4.03) among treated hypertensive participants, and low diastolic blood pressure (OR 2.42; 95% CI, 1.26-4.68) among untreated or nonhypertensive participants. Conclusion Low blood pressure was independently associated with depressive symptoms in both older subjects who were treated for hypertension and those who were not.

Augmentation of systemic blood pressure during spinal cord ischemia to prevent postoperative paraplegia after aortic surgery in a rabbit model

Paraplegia from spinal cord ischemia remains an unresolved complication in thoracoabdominal aortic surgery, with high morbidity and mortality. This study investigated postoperative effects of systemic blood pressure augmentation during ischemia. Spinal cord ischemia was induced in rabbits by infrarenal aortic occlusion for 15 minutes with infused phenylephrine (high blood pressure group, n = 8) or nitroprusside (low blood pressure group, n = 8) or without vasoactive agent (control, n = 8). Spinal cord blood flow, transcranial motor evoked potentials, neurologic outcome, and motor neuron cell damage (apoptosis, necrosis, superoxide generation, myeloperoxidase activity) were evaluated. Mean arterial pressures during ischemia were controlled at 121.9 +/- 2.8, 50.8 +/- 4.3, and 82.3 +/- 10.7 mm Hg in high blood pressure, low blood pressure, and control groups, respectively. In high blood pressure group, high spinal cord blood flow (P < .01), fast recovery of transcranial motor evoked potentials (P < .01), and high neurologic score (P < .05) were observed after ischemia relative to low blood pressure and control groups. At 48 hours after ischemia, there were significantly more viable neurons, fewer terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive neurons, and less alpha-fodrin expression in high blood pressure group than low blood pressure and control groups. Superoxide generation and myeloperoxidase activity at 3 hours after ischemia were suppressed in high blood pressure group relative to low blood pressure group. Augmentation of systemic blood pressure during spinal cord ischemia can reduce ischemic insult and postoperative neurologic adverse events.

Nb/Ta fractionation observed in eclogites from the Chinese Continental Scientific Drilling Project

This paper reports detailed analyses of Nb and Ta concentrations of 19 eclogite samples and their principal mineral constituents from the main drill hole of the Chinese Continental Scientific Drilling Project (CCSD) and nearby outcrops. We observe highly fractionated and overall suprachondritic Nb/Ta values in minerals, e.g., rutile (4.8–87), titanite (12–62) and amphibole (2.0–67). Amphiboles in amphibolites (retrograded from eclogite) can be classified into two groups: a low Nb/Ta group that bears higher Al contents and is thus of higher pressure origin, and a high Nb/Ta, lower pressure group. The former group was likely formed during subduction; the latter may have formed during exhumation in the presence of rutile and titanite. The significant Nb/Ta fractionation in rutile and other minerals may reflect early dehydration of the subducted slab at shallow depths before the formation of rutile, which occurs at depths ≥50 km. The dehydration, with amphiboles existing as the main Nb–Ta-bearing phase, would lead to Nb/Ta fractionation, i.e., forming subchondritic Nb/Ta ratios in the released fluids and, complementarily, suprachondritic Nb/Ta ratios in the residual phases. While a large proportion of the fluids may escape from the slab to the mantle wedge, considerable amounts of the fluids can be retained in hydrous minerals within the descending slab, thus forming hydrated cold eclogites with subchondritic Nb/Ta characteristics. As subduction continues to depths over 50 km, rutile appears and consequently controls the Nb–Ta budget. In the presence of rutile, melting of the hydrated cold eclogites with very low Nb/Ta ratios would form magmas with negative Nb, Ta anomalies and subchondritic Nb/Ta. Further dehydration of the continuously descending slab results in even more fractionated Nb/Ta ratios in subsequently released fluids and residues, providing a feasible explanation for the large Nb/Ta variation observed in the modern arc magmas and residual eclogites.

자세 변화에 따른 의복압 분포 현황

This study was to investigate the distribution of the garment pressure in daily wearing and in ordinary posture. Ninety-nine college women students majoring the fashion were participated for this study. IBP questionnaire, garment pressure, personal preferring pressure sensations(questionnaire), and subjective garment pressure sensations were measured. There were no significant differences between the data of 2003 and those of 2005. Participants preferred T-shirts and jeans and also preferred slightly fitted style to the loose style. They were classified with the high garment pressure group and the low garment pressure group. Garment pressure from lower garments were usually higher in the high garment pressure group than in the low garment pressure group. There was no significant differences in the upper garments weights between two groups. The lower garments weight of the high garment pressure group showed <TEX>$533.3{\pm}182.11g/m^2$</TEX> and that of the low garment pressure group was <TEX>$453.4{\pm}181.6g/m^2$</TEX>. There was a significant difference in the lower garments weight between two groups(p<.01). In a standing posture, there were no significant differences among the distribution of garment pressure. There was a significant garment pressure differences between sitting on a chair and sitting on the floor(p<.001). Participants included in the low garment pressure group felt a higher garment pressure than participants included in the high garment pressure group.

The effects of body temperature control on cytokine production in a rat model of ventilator-induced lung injury

Background and purpose: Injurious ventilation with high peak inspiratory pressure (PIP) is known to cause systemic inflammatory response through cytokine production. This study was performed to examine whether body temperature could regulate cytokine production in ventilator-induced lung injury (VILI) model. Methods: After performing anesthesia, tracheostomy, and catheter insertion, rats were ventilated with 17 cm H 2O of PIP in the low-pressure (LP) group or 35 cm H 2O in the high-pressure (HP) group. Then, each group was divided into three subgroups; hyperthermia (39 °C), normothermia (37 °C), and hypothermia (34 °C) group. Six groups were observed for 6 h. Results: Plasma levels of pro-inflammatory cytokines, TNF-a and IL–6 at 1 h after the start of observation were highest in 39 °C-HP group and were lowest in 34 °C-HP group. Furthermore, sustained high plasma levels of IL-6 were observed only in 39 °C-HP group. In contrast, plasma levels of anti-inflammatory cytokine, IL-10 at 1 h were highest in 34 °C-HP group, and lowest in 39 °C-HP group. Conclusion: The body temperature significantly affects cytokine production in a model of VILI. Body temperature control may be a potentially effective therapeutic modality to regulate cytokine production in VILI.

Compression therapy in breast cancer-related lymphedema: A randomized, controlled comparative study of relation between volume and interface pressure changes

Short stretch bandages are very effective in the initial management of arm lymphedema. However, no studies to date have measured the pressure required to achieve specific amounts of volume reduction. The purpose of this study was to determine whether there is a difference between low and high-pressure bandaging in terms of therapeutically intended volume reduction of the compressed arm. Experimental, randomized and comparative study with two study-groups consisting of high and low initial interface pressure bandages. Thirty-six hospitalized patients in Nij Smellinghe hospital suffering from moderate to severe unilateral breast cancer-related lymphedema not responsive to outpatient treatment were included. Bilateral arm volume was measured by inverse water volumetry before, after two hours and after 24 hours of bandaging. The amount of edema was calculated by subtracting the volume of the diseased arm from that of the contralateral side. Sub-bandage pressure was measured after bandage application and two hours later. Bandages were then re-applied and the pressure was measured again. Twenty-four hours later, the pressure measurement was repeated and bandages were removed for final volumetry. Patients were randomized into two groups: group A received low pressure bandages (20-30 mm Hg) and group B received high pressure bandages (44-58 mm Hg). The main outcome measures were reduction of arm volume and edema volume in the affected arm in both study groups. Secondary outcome parameters were changes in sub-bandage pressure and patient comfort. Median arm volume reduction after two and 24 hours was 104.5 mL (95% confidence interval [CI], 51.2-184.2) (-2.5%) (P < .0001) and 217 mL (95% CI, 143.9-280.2) (-5.2%) (P < .01) for group A and 56.5 mL (95% CI, -2.7-123.1) (n.s.) and 167.5 mL (95% CI, 105.2-316.1) (-4.2%) (P < .01) for group B, respectively. There was no statistically significant difference between the volume changes in group A and group B. After 24 hours, edema decreased by median percentage of 9.2% in group A and 4.8% in group B (n.s.). Bandages in group A were better tolerated. The sub-bandage pressure drop in the first two hours was between 41% and 48% in both treatment groups at both measuring sites. After 24 hours, the pressure drop was between 55% and 63%. No proximal swelling above the bandage was observed. Inelastic, multi-layer, multi-component compression bandages with lower pressure (20-30 mm Hg) are better tolerated and achieve the same amount of arm volume reduction as bandages applied with higher pressure (44-58 mm Hg) in the first 24 hours.

The effects of blood pressure and urokinase on brain injuries after experimental cerebral infarction in rats

Objective: With the proposal of penumbra theory and development of intra-arterial thrombolysis (such as urokinase), the outcome of ischemic cerebrovascular disease is greatly improved. However, the incidence of hemorrhagic transformation (HT) increased concomitantly, and some studies showed a close relationship between blood pressure and HT. The mechanisms of blood pressure and urokinase effect on the incidence of HT are not clear. In this study, we investigated the effects of the different levels of blood pressure and urokinase on the ischemic lesions, the incidence of HT and the expression of matrix metalloproteinase 9 (MMP-9) in the rat ischemia–reperfusion models.Methods: Temporary focal ischemia was induced in male Sprague–Dawley rats using the intraluminal vascular occlusion method. The animals were assigned into four groups (n=11 in each group): low blood pressure group (LP), normal blood pressure group (NP), high blood pressure group (HP) and urokinase/high blood pressure group (UKHP). Adnephrin was applied to enhance the mean arterial blood pressure (MABP) at the beginning of reperfusion. MABP was maintained 20 mmHg higher than the baseline for 1 hour. Sodium nitroprusside was used to decrease MABP by 20 mmHg lower than the baseline for 1 hour. Both urokinase and adnephrin were used concomitantly in the UKHP group. Neurological deficit scores were evaluated at 2 hours (R2h) and 24 hours (R24h) after reperfusion. All rats were decapitated, their brains were sliced into 15-μm-thick slices, and the infarct volume and the visible HT were analysed. Three rats in each group were taken for immunohistochemistry and pathological analysis.Results: There was no significant difference in MABP among the groups at the baseline time points (p>0.05), but blood pressure are definitely increased and decreased in the HP, UKHP, and LP groups. Neurological deficit scores showed no significant difference at R2h among the groups (p=0.443). However, neurological deficit scores showed significant differences at R24h among the groups, the neurological deficits scores of rats in the LP group are significantly higher than that in the other groups. Compared with that of 2 hours after reperfusion, neurological deficit scores deteriorated in the LP group (p=0.047) but was improved in the NP, HP and UKHP groups (p=0.076, 0.002, 0.017, respectively) at 24 hours after reperfusion. The infarct volume in the HP group was apparently smaller than that in the LP group (p=0.006). There was indeed a tendency that HT occurred more frequently in the UKHP group (42.8%) than in the HP (25%) and LP (28.5%) groups. MMP-9 expression showed significant increase around the ischemic lesion areas of the UKHP group and significant decrease in the cortical areas of the LP and HP groups but no significant difference in the basal ganglia of rats of all groups.Conclusion: Mild elevation of blood pressure during reperfusion is supposed to improve neurological outcomes in rats following ischemia/reperfusion. The incidence of HT tended to increase with the elevation of blood pressure and the administration of urokinase. Immunohistochemitry analysis indicated that incidence of HT may correlate with excessive expression of MMP-9.

The relationship between discography pressure and outcome of anterior lumbar interbody fusion for discogenic low back pain.

Objective To explore the relationship between discography pressure and outcome of an-terior lumbar interbody fusion (ALIF) for discogenic low back pain. Methods From April 2004 to June 2006, 65 patients with chronic low back pain were identified as diseogenic origin by pressure controlled discography, 22 cases of which received ALIF after failed conservative treatment for at least 6 months. The surgically treated patients aged 43.6 on the average (range, 25-67). The treated discs located: 8 in L4-5, 12 in L5S1, 2 in both L4-5 and L5S1. 22 cases received ALIF in 24 levels via retroperitoneal approach. The pressure as soon as accordant initially induced pain was recorded during discography. Low pressure (pressure ≤ 300kPa) in 10 cases and high pressure (pressure 300-500 kPa) in 12 cases. At 3 days postoperative, the patients were allowed to leave bed with a brace, and the brace should be used for 3 months. Results All the cases were followed up for average 18 months (range, 6-26 months). At the end of follow-up all the patients recov-ered normal social life and work without any symptoms. Disc height increased from 9.5 mm preoperatively to 13.5 mm postoperatively. Surgery time averaged 90 rain (70-120 rain); blood loss averaged 220 ml (100-400ml). Low pressure group and high pressure group showed no significant different in VAS, ODI, disc height,surgery time and blood loss preoperatively. At 6 months follow up, VAS and ODI improve rates of low pres-sure group account for 82.4% and 90.1% respectively; and those of high pressure group account for 71.7%and 80.6% respectively. No ileus, retrograde ejaculation nor artificial disc translation was noticed during fol-low-up. Conclusion Pressure-controlled discography can increase the diagnostic accuracy of discogenic lowback pain, and a positive discography on low pressure indicates better surgical outcome. Key words: Lumbar vertebrae; Intervertebral disk; Pain; Pressure

Function of portal pressure during operation on the choice of surgical approaches in portal hypertension

To investigate the relationship between perioperative free portal pressure (FPP) after devascularization or spleno-renal shunt operation added devascularization and rebleeding or encephalopathy in patients with portal hypertension, and evaluate the relationship between dynamic changes of FPP and surgical approaches. The clinical data of 170 patients with portal hypertension receiving devascularization or devascularization with spleno-renal shunt operation (combination group) from January 2001 to December 2007 were retrospectively analyzed. All patients were divided into three groups: low pressure group [L group, after devascularization FPP <or= 22 mm Hg (1 mm Hg = 0.133 kPa), n = 43], high pressure group (H group, FPP > 22 mm Hg, n = 60) and combination group (C group, n = 47). There was no significant difference in preoperative Child-Pugh score and pre-operation FPP (P > 0.05) among the three groups. Perioperative FPP, morbidity of rebleeding and encephalopathy were compared with each other. The values of postoperative FPP were (27.1 +/- 1.9) mm Hg, (20.8 +/- 1.8) mm Hg and (21.5 +/- 2.2) mm Hg among the H group, L group and C group respectively. The rebleeding rates were 21.7%, 4.6% and 4.5% among the three groups respectively. All the values in H group were higher than those in L group and C group remarkably. The encephalopathy rate in C group (10.4%) was higher than that in L group (7.0%) or H group (3.3%), but there were no statistical significance (P > 0.05). FPP after splenectomy and devascularization may be a basis of choice of surgical approaches in portal hypertension. The spleno-renal shunt operation should be performed in the patients when FPP is over 22 mm Hg after devascularization.

Lumbar Plexus Block Using High-pressure Injection Leads to Contralateral and Epidural Spread

The main advantage of lumbar plexus block over neuraxial anesthesia is unilateral blockade; however, the relatively common occurrence of bilateral spread (up to 27%) makes this advantage unpredictable. The authors hypothesized that high injection pressures during lumbar plexus block carry a higher risk of bilateral or neuraxial anesthesia. Eighty patients undergoing knee arthroscopy (age 18-65 yr; American Society of Anesthesiologists physical status I or II) during a standard, nerve stimulator-guided lumbar plexus block using 35 ml mepivacaine, 1.5%, were scheduled to be studied. Patients were randomly assigned to receive either a low-pressure (< 15 psi) or a high-pressure (> 20 psi) injection, as assessed by an inline injection pressure monitor (BSmart; Concert Medical LLC, Norwell, MA). The block success rate and the presence of bilateral sensory and/or motor blockade were assessed. An interim analysis was performed at n = 20 after an unexpectedly high number of patients had neuraxial spread, necessitating early termination of the study. Five of 10 patients (50%) in the high-pressure group had a neuraxial block with a dermatomal sensory level T10 or higher. In contrast, no patient in the low-pressure group (n = 10) had evidence of neuraxial spread. Moreover, 6 patients (60%) in the high-pressure group demonstrated bilateral sensory blockade in the femoral distribution, whereas no patient in the low-pressure group had evidence of a bilateral femoral block. Injection of local anesthetic with high injection pressure (> 20 psi) during lumbar plexus block commonly results in unwanted bilateral blockade and is associated with high risk of neuraxial blockade.

Low-pressure pneumoperitoneum versus standard pneumoperitoneum in laparoscopic cholecystectomy, a prospective randomized clinical trial

Post-laparoscopic pain syndrome is well recognized and characterized by abdominal and particularly shoulder tip pain; it occurs frequently following laparoscopic cholecystectomy. The etiology of post-laparoscopic pain can be classified into three aspects: visceral, incision, and shoulder. The origin of shoulder pain is only partly understood, but it is commonly assumed that the cause is overstretching of the diaphragmatic muscle fibers owing to a high rate of insufflations. This study aimed to compare the frequency and intensity of shoulder tip pain between low-pressure (7 mmHg) and standard-pressure (14 mmHg) in a prospective randomized clinical trial. One hundred and forty consecutive patients undergoing elective laparoscopic cholecystectomy were randomized prospectively to either high- or low-pressure pneumoperitoneum and blinded by research nurses who assessed the patients during the postoperative period. The statistical analysis included sex, mean age, weight, American Society of Anesthesiologists (ASA) grade, operative time, complication rate, duration of surgery, conversion rate, postoperative pain by using visual analogue scale, number of analgesic injections, incidence and severity of shoulder tip pain, and postoperative hospital stay. p < 0.05 was considered indicative of significance. The characteristics of the patients were similar in the two groups except for the predominance of males in the standard-pressure group (controls). The procedure was successful in 68 of 70 patients in the low-pressure group compared with in 70 patients in the standard group. Operative time, number of analgesic injections, visual analogue score, and length of postoperative days were similar in both groups. Incidence of shoulder tip pain was higher in the standard-pressure group, but not statistically significantly so (27.9% versus 44.3%) (p = 0.100). Low-pressure pneumoperitoneum tended to be better than standard-pressure pneumoperitoneum in terms of lower incidence of shoulder tip pain, but this difference did not reach statistical significance following elective laparoscopic cholecystectomy.

A Prospective and Randomized Study for Improvement of Acute Asthma by Non-invasive Positive Pressure Ventilation (NPPV)

We hypothesized that non-invasive positive pressure ventilation (NPPV) would improve an acute asthma attack in mild to moderate cases without bronchodilator therapy. A total of 44 eligible patients with acute asthma of mild to moderate severity who had acute attacks were randomly allocated to a NPPV (n=30) or control group (n=14). Both groups received intravenous infusion of hydrocortisone prior to the study. Patients in the NPPV group were divided into two subgroups at random: a high- (n=16) and a low-pressure group (n=14). The former had a fixed expiratory positive airway pressure and inspiratory positive airway pressure of 6 cmH2O and 8 cmH2O, respectively, while the latter had levels of 4 cmH2O and 6 cmH2O, respectively. Effects on the following variables were assessed: FEV(1), oxygen saturation, heart rate, respiratory rate, scores of accessory muscle use and wheezing by auscultation, modified Borg scale score, and mean intra-airway pressure on the monitor. A total of 26 patients completed the study in the NPPV group. The mean percent change in FEV(1) significantly improved after 40 minutes in the high-pressure group compared with that in the control group (p<0.0001). Similar significant improvements in modified Borg scale score and physical examination findings were observed in the high- and low-pressure groups. None of the patients required re-hospitalization or return to the emergency room in either the NPPV or control group. We conclude that higher inflation pressure on NPPV led to clinical improvement in patients with acute asthma attacks of mild to moderate severity.