Bleeding due to needle biopsy: effect of venopirin in an animal model and implications for humans

PURPOSE: This study was undertaken to address the effect of platelet dysfunction on bleeding associated with percutaneous needle biopsy. MATERIALS AND METHODS: With use of an established animal model, 199 biopsies were performed on the livers of 13 anesthetized pigs (95 on control animals, 104 on venopirin-treated animals). The needles used were 16-22-gauge Chiba type, 18-gauge Tru-Cut, and 18-gauge Menghini. The biopsies were performed under direct vision at laparotomy with consistent technique. Blood loss was measured, and the results were compared. Statistical analysis was performed with the Student t test and the Turkey test, after logarithmic transformation of the data. RESULTS: A substantial increase in blood loss resulting from the biopsy procedures was demonstrated in the animals with platelet dysfunction. This was much greater than the effect of either needle size or prothrombin time prolongation previously reported by the authors. CONCLUSION: Platelet function may be an important factor in determining the risk of bleeding due to percutaneous needle biopsy.     

Rat utricular macula: blood flow and stereological assessment of capillary morphology

Vascular compromise has long been proposed as a cause of inner ear disorders. However, the examination of blood flow and its control mechanisms in the vestibular system has been very limited. Combining stereological techniques with the microsphere injection technique, capillary morphology and regional blood flow were determined for the rat utricular macula. Results are as follows: total utricular blood flow 0.158 +/- 0.078 microL/min; blood flow to the neuroepithelium (excluding nerve) 0.0995 +/- 0.046 microL/min; blood flow per unit volume 7.71 +/- 4.31 microL/min per cubic millimeter, neuroepithelial volume 0.01344 +/- 0.0018 mm3; absolute capillary surface area 0.159 +/- 0.039 mm2; mean capillary diameter 5.84 +/- 0.56 microns; absolute capillary length 8.45 +/- 1.6 mm; and capillary lumen volume fraction 0.0175 +/- 0.004. Comparisons to previous data for the posterior canal ampulla indicate that the capillary diameter in the rat utricular macula is smaller; the capillary length is greater; and the end organs are similar with respect to neuroepithelial volume, capillary surface area, and blood flow. The size of the microsphere used in the present study (9.21 microns), in comparison to the mean capillary diameter (5.84 microns) of the utricular neuroepithelium, would indicate that the blood flow data likely represent a minimum value. These findings indirectly indicate that the utricular macula metabolic rate is greater than that of the posterior canal crista, and that there is variation from end organ to end organ in mean capillary diameter.     

Rate of cerebrospinal fluid formation, resistance to reabsorption of cerebrospinal fluid, brain tissue water content, and electroencephalogram during desflurane anesthesia in dogs

Propofol decreases intraocular pressure (IOP) and the IOP response to laryngoscopy and intubation, but the mechanisms responsible for this effect have not been reported. The present study examined the effect of propofol on IOP, intraocular fluid formation and outflow facility, and intraocular compliance. Twenty-two white New Zealand rabbits were anesthetized with halothane (0.8%-1.0% inspired concentration) in nitrous oxide (2 L/min) and oxygen (1 L/min). Muscle paralysis was established with pancuronium, and the lungs were mechanically ventilated through a tracheal tube. Twelve rabbits examined under these conditions served as controls. In the treatment group (n = 10), 6 mg/kg propofol followed by 18 mg.kg-1 x h-1 propofol intravenously was added to halothane/nitrous oxide/oxygen anesthesia. In both groups, a series of intraocular infusions was made via a 30-gauge needle in the anterior chamber, and IOP, the rate of aqueous humor formation (Fa), and trabecular outflow facility (Ctr) were determined using conventional analysis. These same measures, as well as intraocular compliance, were determined using a new method of analysis adapted from the manometric technique for determining cerebrospinal fluid dynamics. IOP was 11.3 +/- 1.8 mm Hg (mean +/- SD) in halothane-anesthetized controls and decreased to 9.4 +/- 2.2 mm Hg when propofol was added to halothane anesthesia (P < 0.05). By conventional analysis, Fa was 2.82 +/- 0.94 microL/min and Ctr was 0.121 +/- 0.044 microL.min-1 x mm Hg-1 in controls. After addition of propofol, Fa decreased by 24% to 2.15 +/- 0.62 microL/min (P < 0.05) and Ctr decreased by 18% to 0.099 +/- 0.034 microL.min-1 x mm Hg-1 (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Recipient to donor conduction of atrial tachycardia following orthotopic heart transplantation

Postspinal headache is one of the most common complications of spinal anesthesia and has repeatedly led to controversy concerning needle size and configuration. In an in vitro investigation, we measured cerebrospinal fluid (CSF) leakage with Sprotte, Whitacre, Quincke, and Atraucan needles under physiological conditions in human dura. The puncture characteristics were examined under an electron microscope. The pencil-point needles show 2-3 times less leakage of CSF compared with the cutting Quincke needles of corresponding size. Between the Sprotte and the Whitacre needles, there were no significant differences. The least loss of CSF occurred with the 26-gauge Atraucan needle. Under the electron microscope, a sharply delineated, persistent perforation channel was shown with the Quincke needles, which may explain the high CSF loss. With pencil-point needles, which push the tissue apart bluntly, a large opening on the inside is found, with some tearing of the dura. However, in contrast to the cutting needles, a persistent perforation channel is not manifested. The 26-gauge Atraucan needle, which both cuts and pushes apart conically, shows a relatively discrete opening on the inside, with slight tears in the dura and arachnoidea but without a visible perforation channel. The results of our study show that larger needles (26-gauge Atraucan) that are easier to handle can lead to good and, in some cases even better, puncture results if they have characteristics of both the cutting and the pencil-point needles. IMPLICATIONS: We compared several brands of pencil-point and standard cutting spinal needles of varying sizes. All pencil-point needles had less cerebrospinal fluid leakage, the least loss occurring with 26-gauge Atraucan needles. Electron microscopic examination of the dura after puncture showed characteristic findings with each needle type. We conclude that the combined cutting and pencil-point characteristics seen in the Atraucan needle may have clinical advantages.     

Mentoring in the context of a training programme for young unemployed adults with physical disability

We describe a modified method for antegrade placement of periurethral collagen in incontinent men. In this technique, a flexible cystoscope is used to guide the placement of a specially designed needle into the bladder neck and external sphincter region via an antegrade transvesical approach. The 19-gauge, 28-cm long needle is passed suprapubically without a sheath. The procedure may be performed with local anesthesia and intravenous sedation only and takes less than 30 minutes.     

Percutaneous biopsy of difficult mediastinal, hilar, and pulmonary lesions by computed tomographic guidance and a modified coaxial technique

A technique for biopsy of small or inaccessible mediastinal, hilar, or pulmonary lesions with computed-tomographic (CT) guidance is described. A modified coaxial system was used in order to make multiple passes possible without multiple punctures. The size of the original puncture needle (23 gauge) provided the inherent safety associated with a fine needle. All repositioning was done using this needle and CT until the lesion was engaged. The hub of the needle was then cut, and a 19-gauge needle was inserted coaxially over the larger needle. After removal of the 23-gauge needle, multiple biopsy specimens were then obtained coaxially with a 22-gauge needle through the 19-gauge needle. One small pneumothorax and no bleeding occurred in 10 instances. Results suggest that the combined use of CT guidance and this modified coaxial system may offer an extra margin of safety for difficult cases.     

A nonlinear spatially variant object-dependent system model for prediction of partial volume effects and scatter in PET

Accurate quantitation of small lesions with positron emission tomography (PET) requires correction for the partial volume effect. Traditional methods that use Gaussian models of the PET system were found to be insufficient. A new approach that models the non-Gaussian object-dependent scatter was developed. The model consists of eight simple functions with a total of 24 parameters. Images of line and disk sources in circular and elliptical cylinders, and an anthropomorphic chest phantom were used to determine the parameter values. Empirical rules to determine these parameter values for various objects based on those for a reference object, a 21.5-cm circular cylinder, were also proposed. For seven spheroids and a 3.4-cm cylinder, pixel values predicted by the model were compared with the measured values. The model-to-measurement-ratio was 1.03+/-0.07 near the center of the spheroids and 0.99+/-0.03 near the center of the 3.4-cm cylinder. In comparison, the standard single Gaussian model had corresponding ratios of 1.27+/-0.09 and 1.24+/-0.03, respectively, and the corresponding ratios for a double Gaussian model were 1.13+/-0.09 and 1.05+/-0.01. Scatter fraction (28.5%) for a line source in the 21.5-cm cylinder was correctly estimated by our model. Because of scatter, we found that errors in the measurement of activity in spheroids with diameters from 0.6 to 3.4 cm were more significant than previously appreciated.     

Plasma cholesteryl ester transfer protein activity in hyper- and hypothyroidism

Thyroid dysfunction is associated with multiple changes in lipoprotein metabolism, and we have determined the effects of thyroid dysfunction on plasma cholesteryl ester transfer protein (CETP) activity. CETP is a plasma protein that mediates the exchange of cholesteryl ester and triglyceride between plasma lipoproteins and plays an important role in high-density lipoprotein metabolism and in the reverse cholesterol transport pathway. Plasma CETP activity was assayed in 18 hyperthyroid and in 17 hypothyroid patients, before and after treatment, by measuring the transfer of cholesteryl esters from exogenous radiolabeled high-density lipoprotein to apolipoprotein B-containing lipoproteins. Plasma CETP activity was increased in hyperthyroid patients, compared with their matched controls (22.11 +/- 8.92% transferred/5 microL.4 h vs. 16.75 +/- 6.48, P < 0.05), whereas in hypothyroid patients, plasma CETP activity was decreased (11.14 +/- 4.84% transferred/5 microL.4 h vs. 17.26 +/- 7.13, P < 0.01). Plasma CETP activity decreased after treatment of thyrotoxicosis, although a significant change was observed, mainly in the severely thyrotoxic patients with free T4 > 100 pmol/L (n = 11, 25.61 +/- 8.12% transferred/5 microL.4 h vs. 21.71 +/- 7.84, P < 0.05). In the hypothyroid patients, there was a significant increase in plasma CETP activity after thyroxine replacement (11.14 +/- 4.84% transferred/5 microL.4 h vs. 15.46 +/- 6.71, P < 0.01). There was a strong positive correlation between log(free T4) and plasma CETP activity (r = 0.51, P < 0.001). In summary, both hyper- and hypothyroidism are associated with significant changes in plasma CETP activity, and these changes are corrected when the patients have been rendered euthyroid.     

Toxoplasma gondii: metabolism of intracellular tachyzoites is affected by host cell ATP production

PURPOSE: To evaluate different-caliber biopsy cutting needles in terms of the benefits and potential risk of bleeding in a swine model. MATERIALS AND METHODS: A total of 190 sequential liver biopsy specimens were obtained in 11 Yorkshire pigs (weight, 50-70 lb [22.5-31.5 kg]) by using 14-, 18-, and 20-gauge cutting needles. For each biopsy procedure, blood loss was determined by weighing sponges used to absorb bleeding, and sample-tissue DNA content was measured with spectrofluorometry. Analysis of variance was used to compare results. RESULTS: The larger the caliber of needle, the greater the absolute blood loss (for 14-gauge, 1.69 g; for 18-gauge, 0.74 g; for 20-gauge, 0.32 g) and DNA content per sample (for 14 gauge, 40.38 microg; for 18-gauge, 12.18 microg; for 20-gauge, 5.86 microg). The ratio of blood loss to amount of DNA recovered did not differ among the different-caliber needles. To obtain the same amount of diagnostic tissue, more passes were needed with the smaller-caliber needles. CONCLUSION: Use of larger-caliber needles is more efficient despite the greater amount of blood loss, because more tissue can be recovered and because fewer passes are necessary, which reduces the chances of complications.     

Etiology and treatment of purulent meningitis in newborns

A microsyringe-needle assembly is described for use in aspiration and microinfusion procedures in the anterior chamber. Assets of a lancet pointed 30-gauge needle, surface anesthesia, and fine control of ocular pressure and aqueous humor volume are stressed. Use of the assembly for emergency treatment of acute congestive glaucoma, surgical paracentesis, aqueous sampling, and drug infusion are described. Drug volumes and concentrations must be maintained at levels which do not damage corneal endothelium.     

The effects of pentobarbital on blood-brain barrier disruption caused by intracarotid injection of hyperosmolar mannitol in rats

This study was performed to evaluate both the effects of pentobarbital on disruption of the blood-brain barrier (BBB) by hyperosmolar mannitol and the relationship between its effect on blood pressure and the integrity of the BBB. Under isoflurane anesthesia, rats in the control group were infused with 25% mannitol into the internal carotid artery before measuring the transfer coefficient (Ki) of 14C alpha-aminoisobutyric acid. Ten minutes before the administration of mannitol, rats received an infusion of pentobarbital: 20 mg/kg in the small-dose group and 50 mg/kg in the large-dose group. In another group of animals (hydralazine group), hydralazine was administered to maintain the mean arterial blood pressure (MAP) at 65 mm Hg during the experimental period. The MAP of the control group (113 +/- 14 mm Hg) was significantly higher (P < 0.002) than that of the small-dose pentobarbital group (78 +/- 13 mm Hg) or the large-dose pentobarbital group (68 +/- 14 mm Hg). In the control group, the Ki of the cortex ipsilateral to the mannitol injection was increased to 4.5 times that of the contralateral cortex (14.5 +/- 7.7 vs 3.2 +/- 0.6 microL x g(-1) x min(-1); P < 0.002). The Ki of the ipsilateral cortex of the small-dose pentobarbital group was 9.7 +/- 5.6 microL x g(-1) x min(-1). The Ki of the ipsilateral cortex of the large-dose pentobarbital group was 5.5 +/- 2.9 microL x g(-1) x min(-1), and lower (-9.0 microL x g(-1) x min(-1)) than that of the control animals (P < 0.05). There was no significant difference in the Ki of the contralateral cortex among any of the three groups of animals. At the same MAP, the Ki of the ipsilateral cortex of the large-dose pentobarbital group was lower (-4.3 microL x g(-1) x min(-1)) than that of the hydralazine group (9.8 +/- 4.6 microL x g(-1) x min(-1)) (P < 0.05). Pentobarbital attenuated the BBB disruption induced by hyperosmolar mannitol. This may be attributed, at least in part, to the blood pressure effect of pentobarbital. Implications: When the blood-brain barrier (BBB) was disrupted by a hyperosmolar solution, pentobarbital attenuated the degree of leakage of the BBB. Systemic hypotension caused by pentobarbital played a significant role in decreasing the leakage. Our study suggests that when the BBB is disrupted, pentobarbital may be effective in protecting the BBB. Furthermore, systemic blood pressure plays an important role in determining the degree of disruption.     

Direct measurement of steroid sulfate and glucuronide conjugates with high-performance liquid chromatography-mass spectrometry

Laser Doppler flowmetry (LDF) is a sensitive method for the measurement of microvascular blood flow in tissue. The method has been found useful for estimating skin, liver, or gastrointestinal blood flow. Whether it can be applied laparoscopically and whether it is able to measure the intraparenchymal blood flow of an intraabdominal organ is still unknown. In a pilot study, 6 pigs received a laparotomy for placement of a 19-gauge LDF needle probe into the renal parenchyma. Three different locations of the lower pole kidney were chosen for the blood flow measurement. The reliability of using the instrument to measure the renal tissue blood flow was assessed by comparison of the results of renal arterial blood flow obtained from a well-established methodology--ultrasonic Doppler flowmetry. Recordings were taken following (a) intravenous administration of 0.005 mg/kg norepinephrine, (b) manual compression of the suprarenal aorta, and (c) intravenous injection of a lethal dose of phenobarbital (50 mg/kg). Measurements of LDF were possible in all kidney units. The renal tissue perfusion detected by LDF correlated excellently with the renal arterial blood flow under different renal perfusion pressures. The feasibility of using LDF probe to measure the renal tissue perfusion in a laparoscopic model was then assessed in 15 pigs. Under pneumoperitoneum, the right kidneys were approached transperitoneally with the animal in the decubitus position. A total of three trocars were used. The peritoneum and Gerota's fascia were incised and the LDF needle probe was manipulated and inserted by an endoforceps into the renal tissue via a 5-mm trocar. The insertion of the LDF needle probe was technically feasible in all 15 kidney units, and the depth of insertion could be adjusted under direct vision. Baseline values for the renal cortical and renal medullary blood flow were 50.1 +/- 17.7 and 8.8 +/- 3.3 ml/min/100 g tissue, respectively. Spatial variations of the LDF measurements averaged 6%, and temporal variations over 15 min averaged 5%. Four additional hemodynamic parameters were simultaneously recorded, including left carotid artery blood flow, aortic blood pressure, inferior vena caval pressure, and intraabdominal pressure. It appears that systemic and renal hemodynamic parameters can be monitored reliably and continuously in the porcine model. This method allows further information concerning hemodynamic changes and safety of laparoscopy to be obtained.     

Role of luminal volume changes in the increase in pulmonary blood flow at birth in sheep

The mechanism by which pulmonary blood flow increases and pulmonary vascular resistance decreases after birth is not fully understood. The aim of this study was to simulate the decrease in lung volume caused by the onset of air-breathing at birth and determine whether it can duplicate the changes in pulmonary blood flow and vascular resistance that occur at this time. In chronically catheterized fetal sheep near term (145 days of gestation), fetal pulmonary arterial blood flow was measured, using coloured microspheres, before and after fetal lung liquid volumes were reduced from 52.2 +/- 2.7 to 21.2 +/- 1.6 ml kg-1. During the 30 min period following the reduction in lung liquid volume, the pulmonary-to-systemic arterial pressure difference decreased from 6.8 +/- 1.2 mmHg (pulmonary > systemic) to 1.6 +/- 0.5 mmHg. Reducing the volume of fetal lung liquid increased pulmonary blood flow from 59.1 +/- 10.5 to 204.2 +/- 40.4 ml min-1 (100 g tissue)-1 and reduced pulmonary vascular resistance from 0.53 +/- 0.20 to 0.14 +/- 0.04 mmHg min ml-1 (100 g tissue)-1. We conclude that a reduction in fetal lung liquid volume, which simulates the reduction in lung volume that occurs at birth, causes a 3- to 4-fold increase in pulmonary blood flow and a reduction in pulmonary vascular resistance of a similar magnitude. Thus, the reduction in lung volume associated with the lung changing from a liquid- to an air-filled organ, may partly account for the increase in pulmonary blood flow and decrease in pulmonary vascular resistance at birth.     

Acute and chronic neutral endopeptidase inhibition in rats with aortocaval shunt

In heart failure, sodium and water retention develop despite elevated plasma levels of atrial natriuretic peptide. Atrial natriuretic peptide is degraded in part by a neutral endopeptidase. Whether neutral endopeptidase inhibition improves sodium and water excretion in heart failure is unknown. We determined the effect of neutral endopeptidase inhibition on plasma levels of atrial natriuretic peptide and the renal response to acute volume expansion in rats with aortocaval shunts and in sham-operated controls. Acute endopeptidase inhibition with SQ 28,603 (30 mg/kg) elevated atrial natriuretic peptide plasma levels in both shunted rats (523 +/- 54 to 1258 +/- 330 pmol/L, P<.05) and controls (184 +/- 28 to 514 +/- 107 pmol/L, P<.05). Urinary cGMP excretion, which reflects renal action, increased in parallel. However, the diuretic and natriuretic responses to acute volume expansion were enhanced only in control rats and not in shunted rats. In contrast to the acute effects, chronic neutral endopeptidase inhibition with SCH 34826 (30 mg/kg twice daily) in shunted rats did not change atrial natriuretic peptide plasma levels or cGMP excretion. Nevertheless, the diuretic and natriuretic responses to acute volume load were increased by chronic endopeptidase inhibition in shunted rats (1789 +/- 154 to 2674 +/- 577 microL/80 min and 99 +/- 31 to 352 +/- 96 micromol/80 min, respectively; P<.05). Chronic endopeptidase inhibition attenuated the cardiac hypertrophic response to aortocaval shunt without changing arterial blood pressure. Our data show that the renal effects of neutral endopeptidase inhibition are not necessarily dependent on changes in atrial natriuretic peptide plasma levels but instead may be mediated by local inhibition of the neutral endopeptidase in the kidney. In addition, chronic endopeptidase inhibition may attenuate heart failure-induced cardiac hypertrophy independent of hemodynamic effects.     

In situ comparison of 665 nm and 633 nm wavelength light penetration in the human prostate gland

The depth of treatment in photodynamic therapy (PDT) of tumors varies with the wavelength of light activating the photosensitizer. New generation photosensitizers that are excited at longer wavelengths have the potential for increasing treatment depths. Tin ethyl etiopurpurin (SnET2), a promising second-generation photosensitizer is maximally activated at 665 nm, which may be significantly more penetrating than 633 nm light currently used with porphyrins in PDT. The penetration of 665 nm and 633 nm wavelength red light in the prostate gland was compared in 11 patients undergoing prostatic biopsies for suspected prostatic cancer. Interstitial optical fibers determined the light attenuation within the prostate gland. Of the 11 patients, 7 had dual wavelength and 4 had single wavelength studies. The mean attenuation coefficients, mueff, for 665 nm and 633 nm wavelength light were 0.32 +/- 0.05 mm-1 and 0.39 +/- 0.05 mm-1, respectively, showing a statistically significant difference (P = 0.0003). This represented a 22% increase in the mean penetration depth and at 10 mm from the delivery fiber there was 1.8 times as much 665 nm light fluence than 633 nm. The mean mueff at 665 nm for benign and malignant prostate tissue were similar (P = 0.42), however, there was significant interpatient variation (mueff ranging from 0.24 to 0.42 mm-1) reflecting biological differences of therapeutic importance. The enhanced light fluence and penetration depth with 665 nm light should allow significantly larger volumes of prostatic tissue to be treated with SnET2-mediated PDT.     

Reactions of vitamin E and its model compound 2,2,5,7,8-pentamethylchroman-6-ol with ozone

A system has been developed to determine intraocular tumor volume, a characteristic that has been estimated in previous studies from linear dimensions using a variety of models. Volume was determined by tracing tumor boundaries in sequential, parallel ultrasound scans, adding the areas and multiplying by the interslice interval. The in vitro accuracy of the technique was within +/- 2%. The mean difference between volumes determined from replicate in vivo scans of intraocular tumors was 4.3%. Serial scan volumes were, on average, 19% smaller than volumes computed from an ellipsoidal model and 13% smaller than area-rotational volumes. Differences of as much as 50% were observed between serial scan volumes and volumes computed with these models. The results indicate that methods based on either linear measurements or the tumor area in a single cross-section will tend to both systematically overestimate tumor volume and suffer from unpredictable, nonsystematic errors.     

Balance of inflammatory cytokines related to severity and mortality of murine sepsis

We tested the hypothesis that, during sepsis, the balance of pro- and anti-inflammatory cytokines is related to severity and survival. Cecal ligation and puncture (CLP) with a large (18-gauge)-, intermediate (21-gauge)-, or small (26-gauge)-diameter needle, or sham laparotomy, was performed on outbred CD-1 mice. Concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and the anti-inflammatory cytokine IL-10 were measured (by enzyme-linked immunosorbent assay) in serum, peritoneal lavage fluid, and liver and lung samples at 4, 8, 24, 48, and 96 h. As the diameter of the CLP needle decreased, the mortality rate decreased (at 48 h: large, 80%; intermediate, 40%; small, 20%; P < 0.05), the TNF-alpha and IL-6 concentrations decreased, and the time-to-peak TNF-alpha expression increased. In contrast, IL-10 concentration increased compared with baseline (serum at 24 h: large, 2.3-fold +/- 1.6-fold; intermediate, 2.0-fold +/- 0.5-fold; small, 49.9-fold +/- 8.3-fold; P < 0.05). Administration of IL-10 (5 microg, intraperitoneal) prior to CLP decreased mortality (P < 0.001). Administration of polyclonal anti-IL-10 serum prior to CLP (0.5 ml intraperitoneal) had the opposite effect and increased mortality (P < 0.001) and TNF-alpha, IL-6, and TNF-alpha mRNA expression compared with controls. Thus, severe sepsis is associated with a largely unopposed inflammatory response, and a largely unopposed inflammatory response (with anti-IL-10) results in severe sepsis and death. Less severe sepsis is associated with greater anti-inflammatory mediator expression, and greater anti-inflammatory mediator expression (with IL-10) results in less severe sepsis. Thus, the balance of inflammatory mediators is related to the severity and mortality of murine sepsis.     

Atraucan: a new needle for spinal anesthesia

BACKGROUND AND OBJECTIVES: Atraucan 26-gauge spinal needles have a tip designed to make a small linear cut (as opposed to a V-shaped cut) in the dura mater. The cut is shorter than the outside diameter of the needle and is dilated as the needle passes through the dura. The needle is used with a 20-gauge introducer. In vitro, it causes less leakage of cerebrospinal fluid than Quincke 26-gauge or Sprotte 24-gauge needles. This study was designed to test the ease of use and any damage caused to the needle tip during lumbar dural puncture. METHODS: This was a multicenter trial (six centers in five countries) involving 362 patients undergoing spinal anesthesia. A detailed questionnaire was filled in for every patient by the anesthesiologist. All the needles were returned to the factory and examined microscopically for damage. RESULTS: Lumbar dural puncture was successful in all but one patient. Spinal anesthesia was satisfactory for the planned surgery in 97%. Microscopy of the needle tips showed only a minor degree (0.01-0.19 mm) of bending in 14%, and none of the tips had a "hook." Postdural puncture headache (PDPH) occurred in nine patients (2.5%), all but one of whom (a 15-year-old male) were females under 55 years of age. CONCLUSIONS: The Atraucan needle is easy to use and has a high success rate in identifying the subarachnoid space. Lumbar dural puncture causes minimal damage to the tip. The incidence of PDPH is low, but a larger comparative study needs to be performed.     

In vitro evaluation of three-dimensional ultrasonography based on magnetic scanhead tracking

The objective of this study was to evaluate the accuracy and precision of a magnetic position sensor system for acquisition of three-dimensional (3D) ultrasound images in volume estimation of phantoms in vitro. Installation of either 0.9% solution of saline at 37 degrees C or distilled water at 20 degrees C to a condom was performed. Scanning was performed either by a continuous or stepwise acquisition. This 3D ultrasound system demonstrated good correlation (r = 0.99-1.0, n = 8) between estimated (EV) and true volumes (TV). The errors were in the range 1.3%+/-0.3% (SEM) to 1.9%+/-0.6%, independent of sound velocity. Scanning through a porcine abdominal wall positioned at the fluid surface yielded a systematic underestimation of the volume: mean (EV - TV) = -7.2+/-0.8 ml. Eight repeated scans of the same volume yielded a coefficient of variation of 1.1%. Interobserver error of the tracing procedure was 2.6%+/-0.9%. This 3D ultrasound system gave high accuracy and precision in volume estimation in vitro, and yielded low interobserver error. A change in ultrasound velocity of approximately 60 m/s did not influence the accuracy significantly. Scanning through an abdominal wall underestimated volumes slightly.     

Effect of UVB 311 nm irradiation on normal human skin

OBJECTIVE: To determine the relative efficacy and morbidity of Ho:YAG versus Nd:YAG laser treatment of bullous lung disease in an animal model. SUMMARY BACKGROUND DATA: Laser coagulation procedures for treatment of emphysematous pulmonary bullae and heterogeneous emphysema continue to evolve. The role of lasers in lung volume reduction surgery remains controversial due to issues of relative efficacy and morbidity. The Nd:YAG laser is most commonly used for these procedures. We hypothesized that the shallower penetration of the Ho:YAG laser may be better suited for laser bullae coagulation and emphysema lung volume reduction with increased efficacy and reduced lung injury. METHODS: Thirty New Zealand White rabbits (15 normal rabbits; 15 with bullous lung disease) were evaluated with Ho:YAG compared to Nd:YAG laser exposures. Bullae were coagulated by either Ho:YAG or Nd:YAG treatment. In all animals (bullous-induced and normals), unaffected lung tissue in the upper lobes and contralateral lungs were treated with 5 spot exposures of Nd:YAG and Ho:YAG, each to assess depth of lung injury. Animals were sacrificed at Days 0, 7, and 21 and their lungs were examined histologically. RESULTS: Ho:YAG and Nd:YAG exposures caused equivalent lung injury to normal lung tissue. In the acute phase, parenchymal necrosis depth was similar for both Ho:YAG and Nd:YAG (850 +/- 273 microns vs. 900 +/- 270 microns respectively, p = 0.7). By Day 7, lung necrosis depth was 925 +/- 133 microns Ho:YAG vs. 1225 +/- 235 microns Nd:YAG (p = 0.33), and lung fibrosis depth was 300 +/- 134 microns Ho:YAG vs. 558 +/- 127 microns Nd:YAG (p = 0.11). By Day 21, pulmonary parenchymal necrosis was not seen. Pleural fibrosis depth was maximal at Day 21, reaching 250 +/- 102 microns for Ho:YAG vs. 300 +/- 156 microns Nd:YAG (P = 0.88). Pleural necrosis depth was 67 +/- 42 microns Ho:YAG vs 48 +/- 34 microns Nd:YAG (p = 0.42) on Day 7 and resolved by Day 21. During surgical coagulation procedures, the Ho:YAG laser was dramatically more efficient in coagulating bullae. The Ho:YAG laser required less exposure at equivalent power and resulted in immediate desiccation of bullae, in sharp contrast to the Nd:YAG laser. CONCLUSIONS: Because the Ho:YAG was more effective and did not result in more acute lung injury than the standard Nd:YAG laser in this study, Ho:YAG lasers may have improved potential for laser treatment of bullae or lung volume reduction surgery (LVRS) compared to Nd:YAG lasers.