变应性鼻炎脱敏治疗的效果观察

目的观察变应性鼻炎（AR）脱敏治疗的效果，探讨影响变应性鼻炎脱敏治疗效果的相关因素。方法对185例AR患者通过皮肤试验，选择敏感变应原浸液，按递增剂量进行常规皮下脱敏治疗。根据患者治疗前后的症状和体征得分情况，分为显效、有效和无效。选择性别、年龄、病程、病情、伴慢性鼻窦炎、伴哮喘、脱敏治疗时间、皮试反应等8个影响变应性鼻炎脱敏治疗效果的可能因素进行多元回归分析，筛查影响脱敏治疗效果的因素。结果总有效率74．6％，其中显效22．9％，有效51．7％。影响脱敏治疗效果的主要因素是治疗时间，即时间越长，效果越好（P〈0．01）；其次是年龄因素，年龄越小，效果越好（P〈0．05）；伴慢性鼻窦炎和伴哮喘也可能影响脱敏治疗效果（P值分别为0．072和0．069）。结论变应性鼻炎脱敏治疗是有效的，脱敏治疗时间越长、年龄越小，效果越好。     

Comparative efficacy of short-term versus long-term cefoxitin prophylaxis against postoperative infection after radical hysterectomy: a prospective study

We report the results of a randomized, double-blind comparison of short-term versus long-term cefoxitin prophylaxis against infections after radical abdominal hysterectomy with pelvic and para-aortic lymphadenectomy. Of 113 evaluable patients, 54 (47.8%) received short-term (three doses) and 59 (52.2%) long-term (12 doses) prophylaxis with intravenous cefoxitin (2 g per dose). No significant differences in demographics, preoperative risk factors, or clinical course were detected between the two groups; nor did we detect significant differences in the incidence of surgical-site-related infections (7.4 versus 5.1%, respectively, P = .61), postoperative urinary tract infection, or other febrile morbidity. We conclude that short-term and long-term cefoxitin prophylaxis are equally effective for the prevention of post-operative surgical-site-related infections after radical hysterectomy.     

Phenomenologic aspects of the acoustic reflex following noise exposure

Thirty-seven normal hearing subjects were exposed to broadband noise for 2 hours at 90 dB (Lp). Measures of behavioral thresholds and acoustic reflex activity were completed prior to and following the noise exposure. As expected, temporary threshold shift was obtained at several different frequencies (1.0-6.0 kHz). In addition, reflex threshold shift occurred for all pure-tone elicitors under evaluation (0.5 to 4.0 kHz). The observed shift in acoustic reflex threshold at 0.5 kHz without a concomitant change in behavioral sensitivity reveals the limitation of utilizing behavioral threshold testing as the sole measure of cochlear disruption. Changes in acoustic reflex onset latency and magnitude were not observed after compensating for shifts in acoustic reflex threshold.     

Surgical anatomy of the petrous canal and posterior cranial fossa in relation to hearing preservation in surgery of acoustic neuroma

The suboccipital (retrosigmoid) and the middle fossa routes are recommended for preservation of hearing in surgery for acoustic neuroma. We carried out a comparative study of the critical distances and bony landmarks on 520 petrous bones. Unlike the transtemporal route, the suboccipital approach offers no landmarks for identification of the common crus, the vestibule or the facial nerve; the lateral portion of the internal auditory canal is not always seen. The fundus can be seen in only 50% of bones without opening the labyrinth.     

Functional residual capacity in normal neonates and children up to 5 years of age determined by a N2 washout method

Functional residual capacity (FRC) was determined in 50 infants by a simplified N2 washout method. Fourteen infants were preterm, four full-term newborns and the rest were 1 month to 5 yr of age. Weight ranged from 1.19 to 25.8 kg. The method gave well reproducible values with a mean coefficient of variation of 3.9%. The FRC values are equally well correlated to weight and length (r = 0.98). The correlation with weight is linear, intercepting the x axis (FRC = 0) at a weight of 480 g, the one with length is best described by a power curve. The course of the regression lines reflects the observation that FRC per kg weight or per cm length is lower in neonates than in larger infants. The FRC measurements are in the same range as values obtained by other investigators using the N2 washout or He-dilution techniques. The values are significantly smaller than thoracic gas volume measurements obtained by plethysmography. This difference may be due to air trapping or to possible methodological problems with the plethysmographic technique. The data demonstrate that FRC can be measured easily and accurately in preterm and older infants using a N2 washout technique.     

Long-term implantation of a system of electrical stimulation of paralyzed laryngeal muscles in dogs

Electrical stimulation of the posterior cricoarytenoid muscle, synchronized with inspiration, was achieved in dogs utilizing a radio frequency stimulus triggered by a chest wall expansion transducer. This system brings about abduction of the paralyzed vocal cord for the entire duration of inspiration, which allows a normal flow of air through the larynx. The implantable part of that system was tested successfully in chronic experiments (up to 11 months) in dogs with experimental paralysis of the recurrent laryngeal nerve. We feel that the system may be suitable for pacing the paralyzed human larynx.     

Binaural acoustic reflex activity following monaural noise exposure in decerebrate chinchillas

Acoustic reflex thresholds, latencies and magnitudes were recorded binaurally in decerebrate chinchillas suffering monaural, temporary noise trauma. Simultaneous recordings of cochlear microphonics from both cochleae during monaural reflex stimulation served as an index for acoustic reflex dynamics. Baseline values of threshold, latency and magnitude were recorded from ipsilateral and contralateral ears prior to a monaural 2-hour exposure to a 0.5-kHz octave-band noise at 100 dB SPL. Reflex dynamics were measured immediately after exposure and again following 1 h of recovery. Cochlear microphonic input-output functions for the exposed ear were completed prior to and after cessation of the noise and after 1 h of recovery. Acoustic reflex threshold and magnitude increased and latency decreased following exposure to noise for both the ipsilateral and contralateral recording conditions. Reflex activity in the nonexposed ear was unaffected. Reflex properties returned to pre-exposure values following recovery. These responses followed the same time course as changes in cochlear sensitivity. Alterations in reflex response following noise exposure is caused by changes at purely peripheral sites.     

Effect of distal endotracheal bias flow on PaCO2 during high frequency oscillatory ventilation

In order to evaluate the effect of distal endotracheal bias flow during HFOV on PaCO2 we studied adult rabbits with normal lungs and those who had meconium-induced lung dysfunction. Animals were studied while 1.0, 1.4 and 1.8 ml/kg tidal volumes (VT) were delivered by a high frequency oscillator. In animals with normal lungs and a 1.0 liter/min distal bias flow, the PaCO2 decreased significantly (p less than 0.01) with all VT used. In animals with meconium instillation the decrease in PaCO2 was also significant (p less than 0.05) at all combinations of VT and distal bias flow. The higher the distal bias flow the more pronounced was the lowering effect on PaCO2. We conclude that during HFOV it is possible to improve CO2 elimination using small additional bias flow delivered near the tip of the endotracheal tube in animals with normal abnormal lung function. This may allow adequate alveolar ventilation with even smaller VT, thus reducing the risk of barotrauma.     

Apnea of prematurity: I. Lung function and regulation of breathing

It has been suggested that apnea of prematurity may be caused by "immaturity" of central control of breathing. To test the validity of this hypothesis tidal volume (VT), alveolar ventilation (VA), alveolar Pco2 (Paco2), esophageal pressure change, and the slope of the CO2 response curve (delta Ve [minute ventilation]/delta Paco2) were determined in 18 infants with apnea (mean of 32 episodes of more than 20 seconds duration per day) and in 18 healthy newborns used as control subjects. The infants were matched for birth weight (1,068 g v 1,065 g), gestational age (30.2 weeks v 30.2 weeks), and postnatal age (8.6 days v 8.3 days). The results were as follows: Vt (4.4 +/- 1.0 mL/kg v 5.3 +/- 1.6 mL/kg), Va (96 +/- 21 mL/kg/min v 129 +/- 33 mL/kg/min), Paco2 (45.4 +/- 8.5 mm Hg v 35.6 +/- 4.7 mm Hg), esophageal pressure change (4.5 +/- 0.9 cm H2O v 6.0 +/- 1.8 cm H2O), delta Ve/delta Paco2 (20.2 +/- 10.6 mL/min/kg/mm Hg CO2 v 40.7 +/- 19.9 mL/min/kg/mm Hg CO2). There was a significant difference between infants with and without apnea for all measurements. The results indicate a decreased respiratory center output and a depressed ventilatory response to CO2 in infants with apnea. As there was no difference between the two groups in pulmonary mechanics or oxygenation, the findings support the hypothesis that a central disturbance in regulation of breathing is the cause of apnea in these infants.