Cardiopulmonary effects of prolonged surgical abdominal retractors application during general anesthesia: a prospective observational comparative study

Abstract Introduction: Increasing abdominal pressures could affect pulmonary compliance and cardiac performance, a fact based on which the aim of the present study to detect the cardiopulmonary burden of multiple retractors application during supine versus lateral abdominal surgeries. We hypothesized that surgical ring multiple retractors application would affect the pulmonary and cardiac functions during both lateral and supine abdominal surgeries. Methods: Prospective observational comparative study on forty surgical patients subdivided into two groups twenty each, comparing pulmonary compliance and cardiac performance before, during and after retractors application, group (S) supine position cystectomy surgery, and group (L) lateral position nephrectomy surgery under general anesthesia, Composite 1ry outcome; dynamic compliance C-dyn and cardiac index CI and Other outcome variables ICON cardio-meter were also recorded. Results: C-dyn and C-stat were significantly decreased late during retractor application in lateral compared to supine surgery with significant decrease compared to basal values all over the surgical time. CI was significantly increased after retractor removal in both of the study groups compared to basal values. PAW P was significantly increased in -lateral compared to supine surgery -with significant increase compared to basal value all over the surgical time in both of the study groups. significant increase in DO2I compared to basal value during both supine and lateral positions. Conclusion: Surgical retraction results in a short-lived significant decreases in lung compliance and cardiac output particularly during the lateral-kidney position than the supine position compliance.

Training and evaluation of donor lung procurement technique in swine models / 器官移植

Objective To investigate the training methods and evaluation parameters for donor lung procurement technique in swine models. Methods The surgical skills of donor lung procurement in 15 swine models were summarized. The operation time, objective evaluation parameters before lung perfusion, gross observation after lung perfusion, the type and frequency of intraoperative errors were assessed. Results All donor lung procurement surgeries were successfully completed in 15 swine models. The mean time interval from skin incision to lung perfusion was 22.6 min. Prior to lung perfusion, the oxygenation index of the donor lung was (501±68) mmHg, (404±100) mL (under the pressure of 15 mmHg) for the tidal volume and (29±4) mL/cmH2O for the static compliance. Along with the increasing surgical frequency, the oxygenation index and tidal volume were improved. Favorable lung inflation was obtained after lung perfusion in a majority of swine models. Intraoperatively, multiple operating errors occurred including dissection error, pulmonary arterial intubation error and procedure error, etc. As the frequency of operation increased, the frequency of surgical errors was significantly decreased. Conclusions After certain training for donor lung procurement in swine models, the incidence of intraoperative procedure error is significantly reduced and the quality of the donor lung tends to be enhanced. Objective parameters, such as oxygenation index and the gross shape of the donor lung can be utilized to evaluate the levels of surgical techniques.

The effect of different positive end expiratory pressure on oxygen delivery after recruitment maneuvers in dogs with acute respiratory distress syndrome / 中华急诊医学杂志

Objective To explore the effect of different positive end expiratory pressures (PEEP) on oxygen delivery (DO2) after recruitment maneuvers (RM) in dogs with acute respiratory distress syndrome (ARDS). Method After ARDS models established in 15 dogs by oleic acid, static P-V (pressure-volume) curves were determined by low flow technique. Lower inflection point (LIP) was set by two-way linear regression methods. RM was operated with the pressure control method. ARDS dog models were randomly divided into three groups, namely PEEP 8 cmH2O group (group A), 12 cmH2O group (group B) and 16cmH2O group (group C) after RM (equivalent to pressure at4 cmH2O under LIP, 4 cmH2O near LIP, and 4 cmH2O above LIP, respectively). Hemodynamics and arterial blood gas analysis were monitored before RM, 0, 5, 10 and 15 min after RM. The recruited volume was measured by P-V curve method 15 min after RM and respiratory mechanics was also observed at the same time. Then DO2 was calculated. The quantitative variables were summarized as the mean and SD. The t-test was used to compare continuous variables between the two independent samples. One-way analysis of variance was used to compare variables among three groups. The level of significance was set at P＜0.05 for all the tests. Results In group A, the levels of PaO2 were significantly reduced 5 min, 10 min and 15 min after RM[(257 ± 23 )mmHg, (253±21)mmHg, and (255±19)mmHg] compared with PaO2 at 0 min [(322 ± 20) mmHg] (P＜0.05).But in group B and group C, the levels of PaO2 5 min, 10 min and 15 min after RM were not lower than level of PaO2 at 0 min after RM (P＞0.05 ). The levels of PaO2 in groups B and C were higher than that in group A at the same time (P＜0.05). The recruited volume distinctly increased with PEEP levels escalated [(50±12 ) mL, (124 ±15) mL, and ( 157 ±10)mL](P＜0.05). However, the increment in the recruited volume from PEEP 8 cmH2O to 12 cmH2O was dramatically greater than that from PEEP 12 cmH2O to 16 cmH2O.There was no significant difference in static compliance between group A and B [(14.3 ± 2.2) mL/cmH2O vs. (17.2±1.4)mL/cmH2O] (P ＞ 0.05 ). But compared with groups A and B, the static compliance in the group C significantly reduced(10.5 ± 0.9) mL/cmH2O ( P ＜ 0.05 ). The ratios of DO2 after RM to DO2 before RM were different at different levels of PEEP. The levels of DO2 after RM[( 1.15 ± 0. 11 ),( 1. 14 ± 0.12), ( 1.14 ± 0. 12) and ( 1.16 ± 0.11 )] increased more greatly than that before RM ( 1.00 ±0.09) in the group B (P ＜ 0.05 ). It did not occurred in the groups A and C. Conclusions The PEEP 12 cmH2O set at near the LIP after RM could be the optimal PEEP. Not only can it improve DO2 and the static compliance, but also maintain oxygenation and the recruited volume after RM.

The Establishment of Normal Values of Tympanogram in Guinea Pigs / 听力学及言语疾病杂志

Objective To investigate the range of normal values of tympanometry of guinea pigs and the possible differences associated with genders and ears. Methods Included in this study were 40 guinea pigs with nor-mal hearing and no ear diseases. Under the anesthetized condition, each guinea pig's tympanogram was recorded, and their values were studied associated with different genders and ears. Results The tympanograms thus obtained were all type A. For all the tympanograms of 80 ears, the equivalent canal volume was about 0.09±0. 02 ml, the static compliance was 0.10 ±0.03 ml, the gradient was 0.14 ±0.06 ml, and the pressure of the peak admittance was -99.44±75.06 daPa . The findings of different gender groups yielded statistic differences in the values of e-quivalent canal volume (P=0. 012) but not in static compliance, gradient and peak admittance pressure (P>0. 05). Typical tympanograms were recorded for the both ears in 40 guinea pigs at the same time. There were no binaural differences (P>0.05). Conclusion The results show significant differences in the equivalent canal volumes be-tween male and female guinea pigs. These tympanograms may serve as a guide to detect middle ear dysfunctions in guinea pigs.

Bilateral Sequential Bronchopulmonary Lavage for Pulmonary Alveolar Proteinosis / 대한마취과학회지

Pulmonary alveolar proteinosis is a rare disease of unknown etiology characterized by the accumulation of surfactant like phospholipids and proteinaceous material in the alveolar space. The removal of lipoproteinaceous material from the alveolar can be the only means of effectively treating the progressive hypoxemia in pulmonary alveolar proteinosis. The current technique of the lavage follows: The procedure can be accomplished by the use of Carlens tube, with lavaging of one lung while the other is ventilated, the ventilated lung is lavaged in a similar manner two or three days later. In this case, we performed sequential bilateral pulmonary lavage. We report a case of broncho-pulmonary lavage in which changes of oxygenation and hemodynamics were observed. We conclude that the procedure can be performed by careful monitoring such as continuous monitoring of S v O2, SpO2, effective static comliance.

Test-Retest Differences and Assistive Function in Detecting Conductive Hearing Loss of lmpedance Audiometry

lmpedance audiometry requires physical modifications during the test, which might influence retest data. Therefore, in Order to interprete retest data meaningfully, the range of variation should be identified in each measure of impedence audiometry. The present study obtained data on the retest variation of peak pressure, acoustic reflex threshold, static compliance and earcanal volume in impedance audiometry. ln addition, the authors wanted to know whether or not impedance data would assist otolaryngologists in the detection of conductive hearing impairment. The variation of the retest data was not clinically nor statistically significant in the measurement except for those of ear canal volume. The data on ear canal volume also suggested that the ear canal increases in size during the teenage period and that male ear canals are larger than those of females in ears over 20 years of age. The impedance data assisted the otolaryngologist in the detection of conductive hearing impairment