Tension Pneumothorax Secondary to Colonic Perforation During Diagnostic Colonoscopy: Report of a Case

We report a case of tension pneumothorax, which occurred secondary to colonic perforation during a colonoscopy. The patient was a 77-year-old woman in whom acute respiratory decompensation developed suddenly during a diagnostic colonoscopy for iron deficiency anemia. We diagnosed bilateral pneumothoraces, tension pneumothorax, pneumomediastinum, pneumoperitoneum, and emphysema of the face, neck, and chest. At laparotomy, a posterior colonic perforation was identified at the site of an ileocolic anastamosis performed 3 years earlier. We performed a primary repair and the patient was discharged from hospital 12 days later. Although diagnostic colonoscopy-induced intestinal perforation is rare, it is the most common and serious complication associated with this procedure. Occasionally, air spreads from the retroperitoneum into continuous tissue planes and decompresses into the adjacent structures. To our knowledge, this is the first report of two unique manifestations of diagnostic colonoscopy-induced intestinal perforation: tension pneumothorax and perforation at the site of a previous anastomosis. Both of these conditions should be considered in the event of acute respiratory failure in the endoscopy suite.     

The Ilizarov external fixator: what remains of the wire pretension after dynamic loading?

Background. Maintenance of wire pretension in an Ilizarov external fixator is dependent on the torque applied to the fixation bolts. We therefore measured immediately after surgery the clinically applied torques. The median value was only 10 N m (range 8–14 N m). We wondered whether this value is appropriate to maintain the wire pretension and thereby to achieve sufficient fracture stability during dynamic loading of the device for a longer period.

Methods. A material testing machine dynamically loaded one wire mounted on one ring. Several configurations were tested.

Results. A quick decrease in wire tension to a steady state situation was seen. In the most stable configuration (20 N m wire fixation torque) 50% of the initial 90 kg wire pretension remained after dynamic loading with 200 N. In the least stable configuration (10 N m torque) considerable wire slippage occurred even without loading and no tension remained after loading!

No plastic deformation of the wires was observed so loss of wire tension was due to slippage of the wires through the fixation bolts.

Interpretation. With the small fixation torques used in clinical practice considerable wire tension is lost even after a few loading cycles. Further research should address the question whether preservation of a higher wire tension during long term loading promotes faster fracture healing.     

The influence of complaint symptoms on health care utilisation, medicine use, and sickness absence. A comparison between retrospective and prospective utilisation

OBJECTIVE: The main aim was to examine the impact of reported individual symptoms on health care utilisation (HCU) in a primary health care practice population and to evaluate the impact of these symptoms on utilisation over time. METHOD: The study was performed in 1055 out of 1442 consecutive adult patients visiting a Swedish health care centre. Logistic regression analyses were applied to assess the relationships between symptoms and HCU outcomes. RESULTS: Each of the 30 symptoms was related to consultations with GPs and a provider of alternative medicine, use of medications and herbals, and sickness absence. Depression and tension groups were the strongest predictors of utilisation. Multisymptomatics had higher OR for most of the outcome variables than those with no symptoms. CONCLUSION: The results of this study show a linear correlation between the numbers of symptoms and increasing GP consultations, medicine use and sickness absences days, and this persisted during the years 2001 and 2002.     

老年人自发性气胸的临床特点

本文报告60岁以上老年人自发性气胸38例,气胸病因以慢支肺气肿最多(21例,55.26％),其次为肺结核(16例,42.10％)。临床表现以呼吸困难,气管移向健侧为多,张力型18例(47.37％)。误诊8例(21.05％)。死亡4例,病死率10.53％。文中强调必须详细询问病史和细致地进行体检,张力型者应以闭式水封瓶引流处理。     

The role of isometric muscle tension in the production of muscle toxicity by phencyclidine and restraint stress

A restraint cage with a strain gauge attached to a movable roof to record the isometric force exerted by rats during restraint is described. The isometric activity score, an integral of the total upward force exerted during restraint, correlated significantly with plasma creatine phosphokinase (CPK) activity in rats following restraint. Phencyclidine 5 mg/kg administered intraperitoneally to rats 15 min prior to 1/2 hr restraint has been shown to produce muscle damage associated with large increases of plasma CPK activity. Dose-response curves for the effects of phencyclidine on isometric activity score and plasma CPK activity were essentially parallel, and isometric activity scores were linearly related to plasma CPK activity. Rats restrained and painfully stimulated on the tail developed both elevated isometric activity scores and elevations of plasma CPK activity. Slopes of the curves relating isometric activity to plasma CPK activity were identical for painfully stimulated and phencyclidine treated rats. Phencyclidine has been reported to produce large increases in locomotor activity in unrestrained rats without muscle damage or elevated plasma CPK activity. Thus, increased isometric muscle tension developed during phencyclidine plus restraint is related to the production of muscle damage and increased efflux of CPK in rats.     

Mechanical properties and ATPase activity in glycerinated cardiac muscle of hyperthyroid rabbit

Isometric tension, tension transients in response to rapid step stretches in length and ATPase activity were measured at constant levels of various Ca²⁺ activations in glycerinated right ventricular papillary muscle ofl-thyroxine-treated (14 daily injections of 0.2 mg/kg) and control rabbits. The isometric tension increased sigmoidally as Ca²⁺ was varied from slightly below pCa 7 to about pCa 6 both in thyroxine-treated and control preparations. The maximum isometric tension in thyroxine-treated preparations, however, was only about 66% of that in control. The tension transients were characterized by clear three distinct phases; the first phase of an immediate tension increase coincident with the stretch, the second phase of a rapid quasi-exponential tension decrease and the third phase of a delayed quasi-exponential tension rise. In thyroxine-treated preparations, relative to controls, the time for 63% tension reduction in the second phase decreased from 39.3±2.8 ms (mean ± SD,n=5) to 20.2±2.0 ms (P<0.001) and the time for 63% tension rise in the third phase decreased from 483.9±14.3 ms to 298±15.9 ms (p<0.001). The ATPase activity increased in a sigmoid fashion with increasing Ca²⁺ from slightly above pCa 7 to slightly below pCa 6 both in thyroxine-treated and control preparations. However, the tension cost (ATPase activity/tension) was about two times greater in the tyyroxine-treated preparations than in controls.     

Laparoscopic herniorrhaphy

The purpose of this study was to evaluate the results of a laparoscopic transabdominal preperitoneal (TAPP) approach to inguinal hernia repair which dissected the entire inguinal floor and repaired the indirect, direct, and femoral areas in all patients without tension. In our series, 183 patients had 205 hernia repairs and were followed for more than 6 months. Of this group, 128 hernias were indirect, 55 direct, 22 pantaloon, 26 recurrent, and 22 bilateral. All 12 females and the first 11 males had a single-buttress repair with polypropylene mesh. The other 160 male patients had a double-buttress repair. With median follow-up of 12 months, ranging from 6 to 21 months, no recurrences were found. Patients returned to normal activity in an average of 1 week. Dissection and buttressing of the entire inguinal floor with mesh appeared to solve the problem of early recurrence first seen in laparoscopic herniorrhaphy.Presented at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), Phoenix, Arizona, USA, 2 April 1993     

Muscle activation during maximal voluntary eccentric and concentric knee extension

Summary The aim of this investigation was to study the relationships among movement velocity, torque output and electromyographic (EMG) activity of the knee extensor muscles under eccentric and concentric loading. Fourteen male subjects performed maximal voluntary eccentric and concentric constant-velocity knee extensions at 45, 90, 180 and 360° · s^–1. Myoelectric signals were recorded, using surface electrodes, from the vastus medialis, vastus lateralis and rectus femoris muscles. For comparison, torque and full-wave rectified EMG signals were amplitude-averaged through the central half (30°–70°) of the range of motion. For each test velocity, eccentric torque was greater than concentric torque (range of mean differences: 20%–146%,P < 0.05). In contrast, EMG activity for all muscles was lower under eccentric loading than velocity-matched concentric loading (7%–31%,P < 0.05). Neither torque output nor EMG activity for the three muscles changed across eccentric test velocities (P > 0.05). While concentric torque increased with decreasing velocity, EMG activity for all muscles decreased with decreasing velocity (P < 0.05). These data suggest that under certain high-tension loading conditions (especially during eccentric muscle actions), the neural drive to the agonist muscles was reduced, despite maximal voluntary effort. This may protect the musculoskeletal system from an injury that could result if the muscle was to become fully activated under these conditions.     

多导张力信号自动记录分析仪的研制

本仪器采用ＣＭＯＳ斩波稳零运算放大器为关键性元件，获得对信号无失真采集。主机前级放大器输入阻抗≥１０（１２）Ω，输入失调电压＜１ｕＶ，温漂０．０５ｕＶ／℃·ｈ，共模抑制比＞１２０ｄＢ。仪器由四个部分组成：１．信号采集；２．Ａ／Ｄ转换（转换速率２．５Ｖ／ｕｓ）；３．计算机实时信号分析和数据处理；４．图形及实验结果打印．特点是能进行不失真的信号采集、实现Ａ／Ｄ转换达到实时分析，极限时进行数据处理和图形打印。     

The effects of tension on microvascular anastomoses

Summary A study was undertaken to determine the effect of tension on microvascular arterial and venous repairs. A standard length of rabbit femoral artery and vein was repaired under tension following excision of a central segment. As larger segments were removed repairs came under increasing tension. Anastomoses under mild or moderate tension which were patent immediately following repair remained open and were not affected by tension. Severe tension occurring after removal of 12 to 14 mm segments in arteries and 6 to 8 mm segments in veins resulted in greater tearing of the endothelium and internal elastic lamina, narrowing, ridging between sutures, and collapse of the vessel wall. Considering the length of the vessel segment mobilized, micro-arteries in the rabbit can be stretched over twice the distance of veins and still remain patent. Lumen narrowing and convolution, coupled with exposure of thrombogenic surfaces beneath the internal elastic lamina at tear holes around sutures, and in areas proximal and distal to the repair site in vessels repaired under tension, are the key factors in the formation of thrombus and anastomotic failure.This work has been carried out under a grant from the National Health and Medical Research Council of Australia.