Geometric hysteresis of alveolated ductal architecture.

Low Reynolds number airflow in the pulmonary acinus and aerosol particle kinetics therein are significantly conditioned by the nature of the tidal motion of alveolar duct geometry. At least two components of the ductal structure are known to exhibit stress-strain hysteresis: smooth muscle within the alveolar entrance rings, and surfactant at the air-tissue interface. We hypothesize that the geometric hysteresis of the alveolar duct is largely determined by the interaction of the amount of smooth muscle and connective tissue in ductal rings, septal tissue properties, and surface tension-surface area characteristics of surfactant. To test this hypothesis, we have extended the well-known structural model of the alveolar duct by Wilson and Bachofen (1982, "A Model for Mechanical Structure of the Alveolar Duct," J. Appl. Physiol. 52(4), pp. 1064-1070) by adding realistic elastic and hysteretic properties of (1) the alveolar entrance ring, (2) septal tissue, and (3) surfactant. With realistic values for tissue and surface properties, we conclude that: (1) there is a significant, and underappreciated, amount of geometric hysteresis in alveolar ductal architecture; and (2) the contribution of smooth muscle and surfactant to geometric hysteresis are of opposite senses, tending toward cancellation. Quantitatively, the geometric hysteresis found experimentally by Miki et al. (1993, "Geometric Hysteresis in Pulmonary Surface-to-Volume Ratio during Tidal Breathing," J. Appl. Physiol. 75(4), pp. 1630-1636) is consistent with little or no smooth muscle tone in anesthetized rabbits in control conditions, and with substantial smooth muscle activation following methacholine challenge. The observed local hysteretic boundary motion of the acinar duct would result in irreversible acinar flow fields, which might be important mechanistic contributors to aerosol mixing and deposition deep in the lung.

Mathematical analysis of the heart rate performance curve during incremental exercise testing.

In this study we performed laboratory treadmill protocols of increasing load. Heart rate was continuously recorded and blood lactate concentration was measured for determination of lactate threshold by means of LTD-max and LT4.0 methods.Our results indicate that the shape of heart rate performance curve (HRPC) during incremental testing depends on the applied exercise protocol (change of initial speed and the step of running speed increase, with the constant stage duration). Depending on the applied protocol, the HRPC can be described by linear, polynomial (S-shaped), and exponential mathematical expression.We presented mathematical procedure for estimation of heart rate threshold points at the level of LTD-max and LT4.0, by means of exponential curve and its relative deflection from the initial trend line (tangent line to exponential curve at the point of starting heart rate). The relative deflection of exponential curve from the initial trend line at the level of LTD-max and/or LT4.0 can be defined, based on the slope of the initial trend line. Using originally developed software that allows mathematical analysis of heart rate-load relation, LTD-max and/or LT4.0 can be estimated without direct measurement of blood lactate concentration.

Anaesthesia in colorectal carcinoma surgery at the Clinic for Digestive Surgery from 1997 to 2007.

BACKGROUND: Colorectal cancers are one of the most present neoplasms in human population. This pathology is one of the most frequent ones at the Clinic for Digestive Surgery in Belgrade. AIM: To investigate if there were any changes in both number and structure of patients with colorectal cancers (age, gender, co-morbidity) as well as in both type and duration of surgical procedures and in providing and maintaining anaesthesia in patients with this disease. METHODS: This is a retrospective study. Research materials were anaesthesiological cards written for patients undergoing surgery in order to treat colorectal cancers at the Clinic for Digestive surgery in both 1997 and 2007. Demographics, co-morbidity, ASA score were the parameters we followed in our survey as well as the type of the resection and duration of these surgical interventions. Besides that providing and maintaining anaesthesia and balance of circulatory volume were considered too. RESULTS: The number of the colorectal surgical interventions has been increased up to 489 (13.1% of all) in 2007 comparing to the number of 379 (13.55% of all) in 1997. The percentage has remained the same because the number of all surgical procedures has been increased. The percentage of the rectal resections is increased highly significante in 2007 (50.1% in 1997; 62.6% in 2007). During the same year the duration of the operations was shortened (mean value 176.31 minutes in 1997, 157.5 minutes in 2007). In 2007 highly statistically significant is bigger amount of colloid and crystalloid infusions that were given for supplementation of circulatory volume (mean value 3294.89 ml in 2007; 2552.22 ml in 1997). On the other hand lower amount of blood was given in 2007 than in 1997 (mean value 102.76 opposite to 488.07) what is statisticly significant. The number of the patients with co-morbidities is not statisticly importantly changed in these two followed years. Anaesthesiology technique has been changed and is monitored by higher use of inhalation anesthetics. They were used more in 2007 (29.65%) for these types of surgical procedures than in 1997 when they had been used almost never. CONCLUSION: In these two followed years there have been significant changes in surgical interventions (type and duration of the operation). Surgical teams are higher specialised for the procedures they use modern technology such as stapplers have better equipment for diagnosing the illnes. The use of modern inhalation anaesthetics has been increased along with reduced amount of blood and derivates used for supplementation of circulatory volume.

[Current opinion in epidural analgesia influence on incidence of complications after major abdominal surgery].

Review article summarizes current knowledge of general and epidural anaesthesia combination for major abdominal surgery and incidence of postoperative complications. Continuous epidural local anaesthetics especially through thoracic placed epidural catheter decrease opioids use and as part of "acute rehabilitation" plays important role in postoperative recovery. Most of the studies showed tion is not dependent on kind of anaesthesia and analgesia. Successfully treated postoperative pain prevents chronic postoperative pain, which is best achieved in abdominal surgery with thoracic epidural use.

[Plantago ovata].

Plantago ovata is a high fibre bulk forming laxative. It absorbs water and expands to provide increased bulk and moisture content to the stool. The increased bulk encourages normal peristalsis and bowel motility. Clinical Indications: Constipation, Fecal Incontinence, Hemorrhoids, Ulcerative Colitis, Appetite, Hyperlipidemia, Diabetes mellitus.

Schizophrenia and polymorphic CAG repeats array of calcium-activated potassium channel (KCNN3) gene in Serbian population.

KCNN3 might be a candidate gene for schizophrenia. The KCNN3 cDNA sequence contains two stretches of CAG trinucleotide repeats encoding two separate polyglutamine segments near the N-terminus of this channel protein. The second CAG repeat is highly polymorphic in the Caucasian population from both Europe and United States. The authors carried out a study to compare the allelic frequency distribution of the CAG repeat in KCNN3 gene in 55 Serbian schizophrenic patients and 46 controls. The data indicate a significant association between longer CAG repeats in second polymorphic KCNN3 region and schizophrenia in the Serbian population.

[Combined spinal-epidural anaesthesia for urgent Hartmann's procedure].

A 46- year old patient without previous history of general anaesthesia was admitted for urgent Hartman's procedure. The suspected tumor of sigmoid colon caused the obstructive ileus with extreme abdominal distension and threatened colon perforation. After induction of anaesthesia and adequate muscle relaxation it appeared that endotrh ileus because of possible regurgitation and aspiration.

[Plantago ovata (Laxomucil) after hemorrhoidectomy]. / Plantago ovata (Laxomucil) posle hemoroidektomije.

The aim of this prospective randomized study is to describe the effects of laxative plantago ovata after open hemorrhoidectomy (Milligan-Morgan). Sixty patients divided into 2 equal groups were included in this study. The first group was treated postoperatively with 2 sachets of bulk agent Laxomucil (3.26 g plantago ovata), twice daily, for a period of twenty days, while the control group was treated with glycerin oil. The p.ovata group patients had a statistically significant shorter postoperative length of hospital stay (2.9 v.s. 4.1 days). Pain after stool was statistically significant more tolerable in the p.ovata group. In conclusion, the application of bulk agent plantago ovata after hemorrhoidectomy shortens the mean postoperative hospital stay, expedites digestive function recovery and lessens the pain after stool.

[Prevention and treatment of organ injury in acute pancreatitis]. / Prevencija i lecenje organskih ostecenja u toku akutnog pankreatitisa.

Acute pancreatitis is illness with unpredictable outcome. In some patients course of illness is progressive and leading to multiple organ dysfunction syndrome often resulting with lethal outcome. During last decade the treatment protocols have changed. Basic pathophysiologic mechanisms leading to progression of the illness, as well as, contemporary diagnostic and treatment possibilities that can prevent occurrence of severe consequences and improve outcome are presented.

[Intraoperative and postoperative complications of splenectomy]. / Intraoperativne i postoperativne komplikacije splenektomije.

Spleen is being surgically removed because of trauma, in diagnostic and-or therapeutical purposes because of the benignant and malignant diseases. The percentage of morbidity during and after splenectomy is relatively low. During surgery might occur bleeding, trauma of the pancreatic tail, stomach, lineal flexure of the colon, left hemidiafragm, left suprarenal gland and upper pole of the left kidney, which must be correspondingly reclaimed during the same intervention. In the early postoperative period, postoperative bleeding, subfrenic abscess, pulmonal atelectasis, bronchopneumonia and left pleural extravasations might occur. Especially is important notification of these events in due time and adequate conservative and surgical treatment. After splenectomy, there is an increase of the number of trombocytes, which might lead to the tromboembolic complications. In the prevention of these complications in the postoperative period prolonged antiagregation therapy is suggested. Postsplenectomy sepsis is very late, general complication of splenectomy, which occurs because of the lower immunity in the child age. To prevent these complications, partial splenectomies, reimplantations of the spleen, prolonged application of the penicillin medicines after splenectomy and antipneumococcal vaccine are performed.

[Aspects of anesthesiology in the treatment of the TRALI (transfusion-related acute lung injury) syndrome]. / Anestezioloski aspekti lecenja TRALI sindroma.

Definition--signs and symptoms which include dispnea, hypertension, high temperature and high productive tracheobronchial secretion. Physical findings are lung oedema in first four hours. Such patients usually require respiratory help. After adequate therapy, symptoms disappeared in 96 hours. In the beginning. TRALI used to be a part of ARDS and it were treated that way. Today, TRALI is understand like substantive group of symptoms.

[New surgical approaches in splenic diseases]. / Novi terapijski pristupi u hirurgiji oboljenja slezine.

To improve the success of postoperative results, in the surgeries of the spleen diseases new procedures had been developed from hematological pretreatment to further operative and postoperative treatment of the patient. Elective splenectomy is quite a big anesthetic challenge. In the period from 1996 to 1998 in the Institute for digestive diseases 147 splenestomies had been done as a consequence of the spleen diseases. Before the operation there is no reason for compensate the platelets if their number is equal or bigger than 50 x 10(9)/l unless the patient is bleeding. If the patient has less than 50 x 10(9)/l the operation shouldn't postponed if we have previously prepared enough doses of platelets from the separator the pool, or the ordinary platelets. Now days at our clinic we operate the patients with extremly plateleptema. The operations have been very successful. The team work of surgeons, anestehsiologists and hemathologist is the most important thing.

Characteristics of ischemic and peri-ischemic regions during ventricular fibrillation in the canine heart.

INTRODUCTION: Although premature beats originating in areas of ischemia have been shown to be important in initiating ventricular fibrillation (VF), the participation of the ischemic zone in maintenance of VF has not been investigated. METHODS AND RESULTS: Ten normal dogs underwent induction of two separate episodes of VF, before and 10 minutes after left anterior descending coronary artery ligation. Ischemic VF was allowed to occur spontaneously or was induced by burst pacing after 10 minutes of ischemia. Unipolar epicardial electrograms were recorded using an 8 x 14 plaque electrode array (interelectrode distance 2.5 mm) placed over the anterior wall. Activation during VF was characterized by VF cycle length (CL) and wavefront organization based on linking analysis of epicardial activation directions at adjacent sites. Individual plaque sites were separated into regions based on electrogram morphology during ischemia: R1 = no ischemia; R2 = mild-to-moderate ischemia (minor ST elevation and QRS widening); and R3 = severe ischemia (marked ST elevation and QRS widening). Percent conduction block was calculated based on the percent of cycles during which sites were not activated during VF. There were no significant differences noted in mean CL or mean percent conduction block in the peri-ischemic region R1 compared to the same region under nonischemic (control) conditions. During ischemia, the mean CL was noted to increase in R2 from 111+/-14 msec (control) to 128+/-29 msec (ischemia) and in R3 from 113+/-14 msec (control) to 150+/-42 msec (ischemia) (P < 0.05). The percentage conduction block in R2 increased from 6%+/-11% (control) to 14%+/-16% (ischemia) and in R3 from 4%+/-6% (control) to 44%+/-21% (ischemia) (P < 0.05). Linking analysis revealed no significant changes in VF organization at distances of 2.5 mm in regions R1 and R2 under both control and ischemic conditions. Premature beats initiating fibrillation originated at the border between the normal and mildly ischemic zones. CONCLUSIONS: (1) Some VF characteristics are altered in ischemic regions including a longer VFCL and greater percentage of functional block. (2) VF characteristics are unchanged in immediately adjacent nonischemic myocardium. (3) Although the ischemic zone may be involved in the initiation of VF and has unique activation characteristics during VF, it does not affect VF characteristics in the adjacent nonischemic zone, suggesting that it may not play a major role in VF maintenance.

[Surgical treatment of liver metastases of colorectal carcinoma]. / Hirursko lecenje metastaza kolorektalnog karcinoma u jetri.

Colorectal carcinoma metastasizes into the liver, but liver-only metastases are infrequent. Liver-only metastases are seen mainly from colorectal carcinoma. This is the only metastatic disease where treatment aimed only or mainly at the liver metastases is employed with curative intent. If liver resection for colorectal metastases is done by an experienced team, adhering to predefined indications, five year survival ranges from 30-40%, operative mortality is 3-5% and the postoperative morbidity is acceptable. New diagnostic techniques have been introduced and indications for liver resection extended. This paper presents the current limitations and possibilities for the surgical management of colorectal metastases in the liver.

[Diagnosis and therapy of adult respiratory distress syndrome in acute pancreatitis]. / Dijagnostika i terapija ARDS-a kod akutnog pankreatitisa.

Acute pancreatitis has high morbidity and mortality. The treatment of these patients includes careful respiratory monitoring. Adult Respiratory Distress Syndrome could be find in 50% of patients, while 40% of these needs intensive care.

[Histopathologic changes in the skin of transplanted microvascular flaps]. / Histopatoloske promene u kozi transplantiranih mikrovaskularnih reznjeva.

During the microvascular transfer, the free flaps tissue is exposed to series of pathophysiological changes (tissue anoxia, tissue acidosis, anaerobic metabolism, wound healing and cicatrisation, degeneration of nerves fibers in the free flaps tissue, etc.) In 1993-1998 period, at the Clinic for Plastic Surgery and Burns at the Military Medical Academy, we analyzed histopathologic changes in the skin taken from the transferred flaps and from the recipient region surroundings of 31 patients with microvascular tissue transfer. The bioptic materials were taken between 6 and 36 months following the free tissue transfer--average 23.6 months. By light microscopy we analyzed histopathologic changes of the epidermis, collagen's fibers, skin adnexa, blood vessels and nerve fibers. The data obtained showed considerable difference in the histopathology test results of the epidermis, collagen's fibers, the skin adnex and the nerve fibers in the transferred free flaps compared to the results obtained from testing recipient region surroundings. The histopathologic tests of the blood vessels did not show considerable comparative difference.

[Importance of oximetry parameters in the detection of hypoxia in the early phase of septic shock]. / Znacaj odnosa oksimetrijskih parametara u otkrivanju hipoksije u ranoj fazi septicnog soka.

The routinely monitored variables in shock stages include: arterial pressure, heart rate, central venous pressure, pulmonary artery wedge pressure and cardiac index. With vigorous therapy it is possible to bring these values back into the normal range in both survivors and nonsurvivors. The therapeutic goal in septic shock stages is to maximize the values of cardiac index, O2 delivery (DO2) and O2 consumption (CO2). The aim of this study is to determine the relationship between O2 delivery and O2 consumption as an early sign of hypoxia. Fifteen patients with septic shock were treated in order to maximize the value of CI, DO2 and VO2. We compared the levels of these parameters between the survivors and nonsurvivors and found no significant differences after 24 hours. High levels of DO2 and VO2 do not exclude tissue hypoxia in the early stage of septic shock.

[Mesenteric panniculitis--case report]. / Mezentericni panikulitis--prikaz bolesnika.

Mesenteric panniculitis is a very rare disease usually involving the mesentery of the small bowel, less frequently the sigmoid colon or other intraabdominal fat tissue. The disease is benign with a favorable prognosis. Diagnosis is, as a rule, established at operation or autopsy and histology. A 58 year old male with this disease is presented. The paticut hod mild abdominal pain and a palpable mass. A tumor of the mesentery was suspected on CT scan. The exact diagnosis was established at operation and confirmed at histology.