Agreement between rhinomanometry and computed tomography-based computational fluid dynamics.

PURPOSE: Active anterior rhinomanometry (AAR) and computed tomography (CT) are standardized methods for the evaluation of nasal obstruction. Recent attempts to correlate AAR with CT-based computational fluid dynamics (CFD) have been controversial. We aimed to investigate this correlation and agreement based on an in-house developed procedure. METHODS: In a pilot study, we retrospectively examined five subjects scheduled for septoplasty, along with preoperative digital volume tomography and AAR. The simulation was performed with Sailfish CFD, a lattice Boltzmann code. We examined the correlation and agreement of pressure derived from AAR (RhinoPress) and simulation (SimPress) and these of resistance during inspiration by 150 Pa pressure drop derived from AAR (RhinoRes150) and simulation (SimRes150). For investigation of correlation between pressures and between resistances, a univariate analysis of variance and a Pearson's correlation were performed, respectively. For investigation of agreement, the Bland-Altman method was used. RESULTS: The correlation coefficient between RhinoPress and SimPress was r = 0.93 (p < 0.001). RhinoPress was similar to SimPress in the less obstructed nasal side and two times greater than SimPress in the more obstructed nasal side. A moderate correlation was found between RhinoRes150 and SimRes150 (r = 0.65; p = 0.041). CONCLUSION: The simulation of rhinomanometry pressure by CT-based CFD seems more feasible with the lattice Boltzmann code in the less obstructed nasal side. In the more obstructed nasal side, error rates of up to 100% were encountered. Our results imply that the pressure and resistance derived from CT-based CFD and AAR were similar, yet not same.

Late subadult ontogeny and adult aging of the human thorax reveals divergent growth trajectories between sexes.

Sexual dimorphism is an important feature of adult thorax morphology, but when and how sex-related differences in the ribcage arise during ontogeny is poorly known. Previous research proposed that sex-related size differences in the nasal region arise during puberty. Therefore, we explore whether ribcage sexual dimorphism also arises at that time and whether this sexual dimorphism is maintained until old age. We measured 526 (semi)landmarks on 80 CT-based human ribcage reconstructions, on individuals ranging from 7 to 65 year-old. The 3D coordinates were submitted to the Procrustes superimposition and analyzed. Our results show that the trajectories of thorax size and shape between sexes diverge at around 12 years of age, and continue slightly diverging until old age. The differential ontogenetic trends cause adult male ribcages to become deeper, shorter, and wider than female. Our results are consistent with the evidence from the cranial respiratory system, with the development of sexual dimorphism probably related to changes in body composition during puberty combined with changes in the reproductive system.

Transfer accuracy of two indirect bonding techniques-an in vitro study with 3D scanned models.

Background and objectives: Indirect bonding (IDB) proved to be an effective method for appropriate bracket positioning in patients. Different methods and materials are available for fabricating transfer trays. This in vitro study was designed to measure and compare the transfer accuracy of two common IDB methods. Materials and methods: Sixty stone models were fabricated and separated in two groups of 30 models each (15 working models, 15 patient models). After placing brackets on the working models, 30 IDB trays were made: 15 silicone (method I) and 15 double-vacuum forms (method II). With these trays, the brackets were transferred to the patient models. The bracket positions were scanned before and after the IDB procedure with an intraoral scanner. The linear and angular discrepancies were then determined digitally by measuring six different dimensions: occluso-cervical, mesio-distal, bucco-lingual, tip, rotation, and torque. Results: The silicone trays showed fewer transfer discrepancies, on average, in all measured dimensions. There were significant differences between the methods in the occluso-cervical (P < 0.001), mesio-distal (P = 0.001), and torque (P = 0.044) dimensions. With both methods, 100 per cent of the horizontal and transversal measurements of both methods were within the clinically acceptable range of 0.25 mm. With method I, 98.5 per cent of the vertical and 95.9 per cent of the angular measurements were within the range of 0.25 mm and 1°, respectively. With method II, 94 per cent of the vertical and 84.8 per cent of the angular measurements were within the clinically acceptable range. Conclusions: Although both transfer methods showed a high precision, silicone trays scored better in terms of accuracy than double-vacuum forms.

3D geometric morphometrics of thorax variation and allometry in Hominoidea.

Ever since the seminal papers of Keith and Schultz, hominoid primate ribcages have been described as either "funnel-" or "barrel-shaped." Following this dichotomic typology, it is currently held that Homo sapiens and hylobatids (gibbons and siamangs) share a barrel-shaped ribcage and that they are more similar to each other than to the funnel-shaped thoraces of great apes (Gorilla, Pan, and Pongo). Other researchers hypothesized that thoracic width and the invagination of the thoracic spine into the thorax are related to allometry. However, analyses that take into account the complex three-dimensional (3D) shape of the ribcage are lacking. Here, we address hypotheses about thorax shape and evolution using 3D morphometrics of thoraces in anatomical connection obtained by computed tomography scans of 23 hominoid cadavers and 10 humans and examining thorax compartments composed of seven ribs (1-7 thorax) and of 11 ribs (1-11 thorax). In the 1-7 thorax analyses, the human thorax is uniquely flat because of torsion of the upper and central ribs, differing from all non-human hominoids including hylobatids. In the 1-11 thorax analyses, humans are markedly different from African great apes, with hylobatids and orangutans intermediate. In full shape space analyses, affinities between orangutans and humans on the one hand and between hylobatids and African great apes on the other are evident. Therefore, we reject the hypothesis that humans and hylobatids bear any special affinities in overall 3D thorax shape to each other. We find that larger thoraces are wider and flatter, with a more invaginated spine, supporting the allometric hypothesis. Hominoid thorax variation shows complex interactions between allometry, rib curves, torsion, and declination, and the morphology of the costo-vertebral joint and the thoracic vertebral column. When considering functional specializations alongside phylogenetic relationships, an overly simplistic dichotomy between funnel-shaped and barrel-shaped thoraces is not supported.

Reconstruction of large cranial defects with poly-methyl-methacrylate (PMMA) using a rapid prototyping model and a new technique for intraoperative implant modeling.

BACKGROUND: Reconstruction of large cranial defects after craniectomy can be accomplished by free-hand poly-methyl-methacrylate (PMMA) or industrially manufactured implants. The free-hand technique often does not achieve satisfactory cosmetic results but is inexpensive. In an attempt to combine the accuracy of specifically manufactured implants with low cost of PMMA. METHODS: Forty-six consecutive patients with large skull defects after trauma or infection were retrospectively analyzed. The defects were reconstructed using computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. The computer file was imported into a rapid prototyping (RP) machine to produce an acrylonitrile-butadiene-styrene model (ABS) of the patient's bony head. The gas-sterilized model was used as a template for the intraoperative modeling of the PMMA cranioplasty. Thus, not the PMMA implant was generated by CAD/CAM technique but the model of the patients head to easily form a well-fitting implant. Cosmetic outcome was rated on a six-tiered scale by the patients after a minimum follow-up of three months. RESULTS: The mean size of the defect was 74.36cm2. The implants fitted well in all patients. Seven patients had a postoperative complication and underwent reoperation. Mean follow-up period was 41 months (range 2-91 months). Results were excellent in 42, good in three and not satisfactory in one patient. Costs per implant were approximately 550 Euros. CONCLUSION: PMMA implants fabricated in-house by direct molding using a bio-model of the patients bony head are easily produced, fit properly and are inexpensive compared to cranial implants fabricated with other RP or milling techniques.

Ontogeny of 3D rib curvature and its importance for the understanding of human thorax development.

OBJECTIVES: Sagittal and axial rib orientation relative to the spine are two factors that modify rib cage morphology during ontogeny. Some studies suggest that these factors do not operate in the same way at the upper (ribs 1-5) and lower thorax (ribs 6-10) during postnatal growth, but it is unknown if the ontogenetic thoracic changes are produced by morphological changes of the ribs (intrinsic rib factors) or by external factors related to costal joints (extrinsic rib factors). MATERIAL AND METHODS: To clarify these questions, we applied 3D geometric morphometrics of landmarks and sliding semilandmarks (N = 20/rib) to 280 individual ribs (1-10) of Homo sapiens comprising the entire human ontogeny and growth simulations were carried out. RESULTS: PCA shows that intrinsic rib factors (rib torsion and axial rib curvature) are ontogenetic factors of variability that contribute to configuring the adult thorax shape. Moreover, growth simulations and regression slopes suggest that the upper thorax unit is comprised by ribs 1-7 and the lower unit at least by ribs 8-10. DISCUSSION: These results suggest anatomical constraints for ontogenetic rib variation, since ribs 1-7 (true ribs) are directly linked to the sternum. Moreover, these results are supported by functional anatomy because pulmonary kinematics would influence the upper unit and diaphragmatic kinematics would influence the lower one. Our findings are relevant not only to understanding how changes at individual ribs contribute to the adult thorax morphology, but also to the development and evolution of the modern human rib cage.

The relevance of the first ribs of the El Sidrón site (Asturias, Spain) for the understanding of the Neandertal thorax.

Reconstructing the morphology of the Neanderthal rib cage not only provides information about the general evolution of human body shape but also aids understanding of functional anatomy and energetics. Despite this paleobiological importance there is still debate about the nature and extent of variations in the size and shape of the Neandertal thorax. The El Sidrón Neandertals can be used to contribute to this debate, providing new costal remains ranging from fully preserved and undistorted ribs to highly fragmented elements. Six first ribs are particularly well preserved and offer the opportunity to analyze thorax morphology in Neandertals. The aims of this paper are to present this new material, to compare the ontogenetic trajectories of the first ribs between Neandertals and modern humans, and, using geometric morphometrics, to test the hypothesis of morphological integration between the first rib and overall thorax morphology. The first ribs of the El Sidrón adult Neandertals are smaller in centroid size and tend to be less curved when compared with those of modern humans, but are similar to Kebara 2. Our results further show that the straightening of the first ribs is significantly correlated with a straightening of the ribs of the upper thorax (R = 0.66; p < 0.0001) in modern humans, suggesting modularity in the upper and lower thorax units as reported in other hominins. It also supports the hypothesis that the upper thorax of Neandertals differs in shape from modern humans with more anteriorly projecting upper ribs during inspiration. These differences could have biomechanical consequences and account for stronger muscle attachments in Neandertals. Different upper thorax shape would also imply a different spatial arrangement of the shoulder girdle and articulation with the humerus (torsion) and its connection to the upper thorax. Future research should address these inferences in the context of Neandertal overall body morphology.

Application of micro-computed tomography to microstructure studies of the medicinal fungus Hericium coralloides.

The potential of 3-D nondestructive imaging techniques such as micro-computed tomography (micro-CT) was evaluated to study morphological patterns of the potential medicinal fungus Hericium coralloides (Basidiomycota). Micro-CT results were correlated with histological information gained from scanning electron microscopy (SEM) and light microscopy (LM). It is demonstrated that the combination of these imaging methods results in a more distinct picture of the morphology of the edible and potentially medicinal Hericium coralloides basidiomata. In addition we have created 3-D reconstructions and visualizations based on micro-CT imagery from a randomly selected part of the upper region of a fresh H. coralloides basidioma: Analyses for the first time allowed an approximation of the evolutionary effectiveness of this bizarrely formed basidioma type in terms of the investment of tissue biomass and its reproductive output (production of basidiospores).

An intra-individual comparison of MRI, [18F]-FET and [18F]-FLT PET in patients with high-grade gliomas.

OBJECTIVES: Intra-individual spatial overlap analysis of tumor volumes assessed by MRI, the amino acid PET tracer [18F]-FET and the nucleoside PET tracer [18F]-FLT in high-grade gliomas (HGG). METHODS: MRI, [18F]-FET and [18F]-FLT PET data sets were retrospectively analyzed in 23 HGG patients. Morphologic tumor volumes on MRI (post-contrast T1 (cT1) and T2 images) were calculated using a semi-automatic image segmentation method. Metabolic tumor volumes for [18F]-FET and [18F]-FLT PETs were determined by image segmentation using a threshold-based volume of interest analysis. After co-registration with MRI the morphologic and metabolic tumor volumes were compared on an intra-individual basis in order to estimate spatial overlaps using the Spearman's rank correlation coefficient and the Mann-Whitney U test. RESULTS: [18F]-FLT uptake was negative in tumors with no or only moderate contrast enhancement on MRI, detecting only 21 of 23 (91%) HGG. In addition, [18F]-FLT uptake was mainly restricted to cT1 tumor areas on MRI and [18F]-FLT volumes strongly correlated with cT1 volumes (r = 0.841, p<0.001). In contrast, [18F]-FET PET detected 22 of 23 (96%) HGG. [18F]-FET uptake beyond areas of cT1 was found in 61% of cases and [18F]-FET volumes showed only a moderate correlation with cT1 volumes (r = 0.573, p<0.001). Metabolic tumor volumes beyond cT1 tumor areas were significantly larger for [18F]-FET compared to [18F]-FLT tracer uptake (8.3 vs. 2.7 cm3, p<0.001). CONCLUSION: In HGG [18F]-FET but not [18F]-FLT PET was able to detect metabolic active tumor tissue beyond contrast enhancing tumor on MRI. In contrast to [18F]-FET, blood-brain barrier breakdown seems to be a prerequisite for [18F]-FLT tracer uptake.

Differential growth and development of the upper and lower human thorax.

The difficulties in quantifying the 3D form and spatial relationships of the skeletal components of the ribcage present a barrier to studies of the growth of the thoracic skeleton. Thus, most studies to date have relied on traditional measurements such as distances and indices from single or few ribs. It is currently known that adult-like thoracic shape is achieved early, by the end of the second postnatal year, with the circular cross-section of the newborn thorax transforming into the ovoid shape of adults; and that the ribs become inclined such that their anterior borders come to lie inferior to their posterior. Here we present a study that revisits growth changes using geometric morphometrics applied to extensive landmark data taken from the ribcage. We digitized 402 (semi) landmarks on 3D reconstructions to assess growth changes in 27 computed tomography-scanned modern humans representing newborns to adults of both sexes. Our analyses show a curved ontogenetic trajectory, resulting from different ontogenetic growth allometries of upper and lower thoracic units. Adult thoracic morphology is achieved later than predicted, by diverse modifications in different anatomical regions during different ontogenetic stages. Besides a marked increase in antero-posterior dimensions, there is an increase in medio-lateral dimensions of the upper thorax, relative to the lower thorax. This transforms the pyramidal infant thorax into the barrel-shaped one of adults. Rib descent is produced by complex changes in 3D curvature. Developmental differences between upper and lower thoracic regions relate to differential timings and rates of maturation of the respiratory and digestive systems, the spine and the locomotor system. Our findings are relevant to understanding how changes in the relative rates of growth of these systems and structures impacted on the development and evolution of modern human body shape.

Sheep as a large animal model for middle and inner ear implantable hearing devices: a feasibility study in cadavers.

OBJECTIVE: Currently, no large animal model exists for surgical-experimental exploratory analysis of implantable hearing devices. In a histomorphometric study, we sought to investigate whether sheep or pig cochleae are suitable for this purpose and whether device implantation is feasible. METHODS: Skulls of pig and sheep cadavers were examined using high-resolution 128-slice computed tomography (CT) to study anatomic relationships. A cochlear implant and an active middle ear implant could be successfully implanted into the sheep's inner and middle ear, respectively. Correct device placement was verified by CT and histology. The cochlear anatomy of the sheep was further studied by micro-CT and histology. RESULTS: Our investigations indicate that the sheep is a suitable animal model for implantation of implantable hearing devices. The implantation of the devices was successfully performed by access through a mastoidectomy. The histologic, morphologic, and micro-CT study of the sheep cochlea showed that it is highly similar to the human cochlea. The temporal bone of the pig was not suitable for these microsurgical procedures because the middle and inner ear were not accessible owing to distinct soft and fatty tissue coverage of the mastoid. CONCLUSION: The sheep is an appropriate large animal model for experimental studies with implantable hearing devices, whereas the pig is not.

ADC histograms predict response to anti-angiogenic therapy in patients with recurrent high-grade glioma.

INTRODUCTION: The purpose of this study is to evaluate apparent diffusion coefficient (ADC) maps to distinguish anti-vascular and anti-tumor effects in the course of anti-angiogenic treatment of recurrent high-grade gliomas (rHGG) as compared to standard magnetic resonance imaging (MRI). METHODS: This retrospective study analyzed ADC maps from diffusion-weighted MRI in 14 rHGG patients during bevacizumab/irinotecan (B/I) therapy. Applying image segmentation, volumes of contrast-enhanced lesions in T1 sequences and of hyperintense T2 lesions (hT2) were calculated. hT2 were defined as regions of interest (ROI) and registered to corresponding ADC maps (hT2-ADC). Histograms were calculated from hT2-ADC ROIs. Thereafter, histogram asymmetry termed "skewness" was calculated and compared to progression-free survival (PFS) as defined by the Response Assessment Neuro-Oncology (RANO) Working Group criteria. RESULTS: At 8-12 weeks follow-up, seven (50%) patients showed a partial response, three (21.4%) patients were stable, and four (28.6%) patients progressed according to RANO criteria. hT2-ADC histograms demonstrated statistically significant changes in skewness in relation to PFS at 6 months. Patients with increasing skewness (n = 11) following B/I therapy had significantly shorter PFS than did patients with decreasing or stable skewness values (n = 3, median percentage change in skewness 54% versus -3%, p = 0.04). CONCLUSION: In rHGG patients, the change in ADC histogram skewness may be predictive for treatment response early in the course of anti-angiogenic therapy and more sensitive than treatment assessment based solely on RANO criteria.

Body size, body proportions, and mobility in the Tyrolean "Iceman".

Body mass and structural properties of the femoral and tibial midshafts of the "Iceman," a late Neolithic (5,200 BP) mummy found in the Tyrolean Alps, are determined from computed tomographic scans of his body, and compared with those of a sample of 139 males spanning the European early Upper Paleolithic through the Bronze Age. Two methods, based on femoral head breadth and estimated stature/bi-iliac (pelvic) breath, yield identical body-mass estimates of 61 kg for the Iceman. In combination with his estimated stature of 158 cm, this indicates a short but relatively wide or stocky body compared to our total sample. His femur is about average in strength compared to our late Neolithic (Eneolithic) males, but his tibia is well above average. His femur also shows adaptations for his relatively broad body (mediolateral strengthening), while his tibia shows adaptations for high mobility over rough terrain (anteroposterior strengthening). In many respects, his tibia more closely resembles those of European Mesolithic rather than Neolithic males, which may reflect a more mobile lifestyle than was characteristic of most Neolithic males, perhaps related to a pastoral subsistence strategy. There are indications that mobility in general declined between the European Mesolithic and late Neolithic, and that body size and shape may have become more variable throughout the continent following the Upper Paleolithic.

Matching lung volume data sets--a novel approach.

There is a significant demand in matching CT datasets of the lung. The increasing number of CT slices per examination due to the higher resolution of modern CT scanners and the need for quantification of the progress of disease and healing processes in follow-up studies. A volunteer's lung was scanned by the means of multidetector CT in two different states of ventilation. The necessary lung structures for the matching procedure like lung surface and branching points were segmented. A thin-plate spline method was used to calculate the matched lung volume. The preliminary results show an average error of 2 voxel, i.e. 2mm. The calculation of the transformation matrix takes about one second on a conventional PC, which is considerably faster than other methods described in literature. The method described may be apt to be introduced in radiological practice when it comes to compare high resolution CT scans in follow-up studies quantitatively.

Power Doppler ultrasound imaging for quantification of urinary bladder neck blood flow changes.

This study was designed to evaluate power Doppler imaging for assessment of urinary bladder neck blood flow in comparison with laser Doppler flowmetry (LDF) in an animal model. Transrectal power Doppler ultrasound (US) and LDF of the urinary bladder neck were performed in three anesthetized pigs during comparative cystometry. Normal saline (NaCl) was used for the first run, followed by a second run with 0.2 mol/L potassium chloride (KCl). Standardized sonographic equipment settings (Acuson Sequoia 512); MountainView, CA) were used for power Doppler imaging. Computer-assisted calculation of color pixel density (CPD) of power Doppler images was performed using Scion Image) software image analysis. Tissue perfusion units (TPU) were measured using a BLF21 laser Doppler flowmeter (Transonic Systems Inc., Ithaca, NY, USA). The power Doppler results were compared with the findings obtained by LDF. NaCl filling resulted in a mean CPD increase at the bladder neck from 18.65 (+/- 1.78) at empty bladder to 37.8 (+/- 1.84) at 100 mL and to 88.32 (+/- 1.35) at full bladder capacity (C(max)) of 270 mL, respectively. With KCl filling, a mean CPD increase from 18.65 (+/- 1.78) to 59.63 (+/- 0.5) at 100 mL and 110.82 (+/- 2.98) at full bladder capacity (270 mL) was observed. The CPD increase was significantly higher for KCl than with NaCl (p < 0.001). With NaCl filling, bladder neck blood flow increased from 22 TPU (empty) to 46 TPU (100 mL) and 62.5 TPU at C(max), compared to 22 TPU, 50 TPU and 102.5 TPU with KCl. CPD and TPU measurements showed a strong correlation at p = 0.01. In conclusion, transrectal power Doppler US image quantification is a feasible and accurate method for assessing blood flow changes in the urinary bladder neck.

The influence of left renal vein entrapment on outcome after surgical varicocele repair: a color Doppler sonographic demonstration.

OBJECTIVE: To evaluate the impact of left renal vein entrapment on outcome after surgical varicocele repair using color Doppler sonography. METHODS: Eighty-four men had varicoceles on color Doppler sonography (2 right sided, 74 left sided, and 8 bilateral), which were diagnosed on the basis of a venous diameter of 3 mm or greater and venous retrograde flow in the pampiniform plexus of veins during the Valsalva maneuver or when changing from a supine to an upright position. Diagnosis of the left renal vein entrapment was based on the following criteria: antero-posterior diameter of greater than 1 cm and peak velocity of less than 15 cm/s for the left renal vein at the mid portion and anteroposterior diameter of less than 0.2 cm and peak velocity of greater than 110 cm/s (or, alternatively, a diameter ratio and peak velocity ratio of >5) for the left renal vein between the aorta and superior mesenteric artery. All patients underwent surgical varicocele repair. In postoperative follow-up, we compared the presence of left renal vein entrapment with the frequency of varicocele recurrence. RESULTS: Sixteen (19%) of 84 patients had left renal vein entrapment with a left-sided varicocele. Postoperatively (mean follow-up +/- SD, 19.3 +/- 11.7 months), 27 (32.2%) of 84 had varicocele recurrence, including all 16 patients with left renal vein entrapment and 11 (20.1%) of 68 patients without left renal vein entrapment. The varicocele recurrence rate was significantly greater in patients with left renal vein entrapment (P < .001, Fisher exact test). CONCLUSIONS: The presence of left renal vein entrapment resulted in a significantly higher varicocele recurrence rate. Patients with varicoceles should routinely be evaluated for the presence of left renal vein entrapment before surgical repair.

Electronic removal of encrustations inside the Steinheim cranium reveals paranasal sinus features and deformations, and provides a revised endocranial volume estimate.

Features in the endocranium, as revealed by computed tomography (CT) scans of largely complete mid-Pleistocene crania, have helped elucidate unexpected affinities in the genus Homo. Because of its extensive encrustations and deformations, it has been difficult to repeat such analyses with the Steinheim cranium. Here, we present several advances in the analysis of this Homo heidelbergensis cranium by applying filter algorithms and image editing techniques to its CT scan. First, we show how the encrustations have been removed electronically, revealing interesting peculiarities, particularly the many directions of the deformations. Second, we point out similarities and differences between the frontal and sphenoidal sinuses of the Steinheim, Petralona, and Broken Hill (Kabwe) crania. Third, we assess the extent of the endocranial deformations and, fourth, their implications for our estimation of the braincase volume.

The iceman: discovery and imaging.

The anatomic features of a 5,300-year-old mummy, the iceman, were documented with conventional radiographic, portable computed radiographic, and conventional and spiral computed tomographic images obtained between September 1991 and June 2001. A team of scientists and radiologists from Austria, Italy, and the United States supervised the examinations and interpreted the images. The images demonstrated excellent preservation of the mineralized skeleton with profound dehydration of the soft tissues. The skeleton exhibited several types of trauma, including (a) healed rib fractures, (b) hairline skull fractures and a compression deformity of the thorax, probably acquired while encased in the glacier, and (c) damage acquired during the effort to recover the corpse. Skeletal variants were present, as was evidence of degenerative arthritis, frostbite, vascular calcification, and adaptation to cultural and geographic influences. In terms of anatomy and apparent health-related conditions, the iceman was very similar to modern humans. An arrowhead lodged between the rib cage and the left scapula was the probable cause of the iceman's death. Study of the images also provided insight regarding postmortem processes that led to the iceman's mummification.

Pulmonary gas exchange after cardiopulmonary resuscitation with either vasopressin or epinephrine.

OBJECTIVE: It is well established that epinephrine administered during cardiopulmonary resuscitation results in pulmonary gas exchange disturbances. It is uncertain how vasopressin affects gas exchange after cardiopulmonary resuscitation. DESIGN: Prospective, randomized experimental study. SETTING: Animal research laboratory. SUBJECTS: Twenty domestic pigs. INTERVENTIONS: Animals were subjected to ventricular fibrillation and cardiopulmonary resuscitation by using either vasopressin or epinephrine. Hemodynamic and pulmonary gas exchange (multiple inert gas elimination technique) variables were recorded before cardiopulmonary resuscitation and 10, 30, 60, and 120 mins after return of spontaneous circulation when either epinephrine (control) or vasopressin was used. MEASUREMENTS AND MAIN RESULTS: At 10 mins after return of spontaneous circulation, blood flow to low V /Q lung units was increased in animals treated with epinephrine (17.8 +/- 6 vs. 2.6 +/- 3%, mean +/- sd, p<.01). Resulting carbon dioxide elimination was impaired in animals treated with epinephrine but not in animals treated with vasopressin (PaCO2, 55 +/- 2 vs. 46 +/- 4 torr, p<.05). Thirty minutes after return of spontaneous circulation, blood flow to lung units with a normal VA /Q ratio was reduced in animals treated with epinephrine (79 +/- 1 vs. 84 +/- 12%, p<.05), resulting in a depressed PaO2 (147 +/- 4 vs. 127 +/- 10 torr, p<.05). CONCLUSION: Vasopressin compared with epinephrine for cardiopulmonary resuscitation resulted in better gas exchange variables in the early postresuscitation phase.