Optimal endexpiratory airway pressure for ventilated patients

In patients ventilated for acute respiratory failure PEEP was changed either by gradual increase and decrease (5 cm H₂O/min) or in steps of 5 cm H₂O. The effects on gas exchange, pulmonary mechanics and pulmonary and systemic circulation were studied. Total compliance did not change uniformly and cardiac index decreased so much due to PEEP that the increase in P_aO₂ could not prevent the decrease of arterial oxygen transport. No variable was found helpful to predict the best PEEP in a clinical situation.With the support of the Swiss National Fund for the advancement of Scientific Research, Berne. Application No. 3.831-0.79     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

持续正压通气合并抗左心衰治疗新生儿肺出血疗效观察

本文报告１９９３年１２月至１９９５年１１月新生儿肺出血的治疗效果。两年内有３７例新生儿肺出血在本科治疗，为了评价持续正压通气（ＣＰＰＶ）与ＣＰＰＶ加抗左心衰两种方法的效果，一组１５例（观察组）按ＣＰＰＶ同时行抗左心衰处理，而另一组２２例（对照组）仅以ＣＰＰＶ治疗。观察组治疗后的抢救成功率为６６．６％（１０／１５），而对照组治疗抢救成功率是２２．７％（５／２２）。前后两组成功率的差别（ｘ２＝７．１４，Ｐ＜０．０１）有高度显著性。提示新生儿肺出血除应使用ＣＰＰＶ外．近必须及时控制左心衰竭。     

支气管用吸痰管行气道吸痰配合持续正压通气在治疗重症左心衰竭中的作用

目的探讨支气管用吸痰管行气道吸痰配合持续正压通气在治疗重症左心衰竭患者监护指标(SpO2,心率,收缩压)的影响。方法将48例重症左心衰竭患者分为三个阶段观察分析监护指标(SpO2,心率,收缩压)的变化情况,第一阶段即患者未进行持续正压通气和支气管吸痰,第二阶段是进行持续正压通气5min后,第三阶段是持续正压通气间歇支气管吸痰5min后。结果第二阶段和第一阶段;第三阶段和第二阶段之间心电监护指标差异都有统计学意义(P<0.05),二、三阶段都比前一阶段在氧合方面都有好转。结论持续正压通气配合支气管吸痰在改善左心衰竭患者的氧合有良好作用。     

Intermittent and continuous positive-pressure ventilation in the prophylaxis of endotoxin-induced lung insufficiency. A study in pigs

The effects of intermittent and continuous positive-pressure ventilation (IPPV and CPPV) instituted prophylactically were evaluated in a porcine model of endotoxin-induced pulmonary and cardiovascular failure. Pigs under ketamine anaesthesia were infused i.v. with E. coli endotoxin over 6 h. Twenty animals, breathing air spontaneously, received endotoxin without treatment. Fifteen animals were treated prophylactically with IPPV (normoventilation with air). Nine animals received prophylactic treatment with CPPV (positive end-expiratory pressure 0.8 kPa (8 cmH2O). Endotoxin infusion in spontaneously breathing animals caused profound deterioration of pulmonary gas exchange, a marked rise in pulmonary vascular resistance (PVR) and a moderate increase in extravascular lung water (EVLW). Cardiac output (Qt) and O2 delivery decreased considerably. Metabolic acidosis indicated oxygen deficit. Eleven of 20 animals died during the observation period. IPPV improved arterial oxygenation during endotoxin infusion, and the increase in EVLW tended to be lower. The alterations in pulmonary haemodynamics, Qt and O2 delivery, were of the same magnitude as in spontaneously breathing animals. Survival was improved. CPPV fully prevented the deterioration in pulmonary gas exchange and the development of pulmonary oedema. There was an accentuated increase in PVR. Qt and O2 delivery decreased markedly and a severe metabolic acidosis developed. All animals treated with CPPV died during the observation period. These results indicate that prophylactic IPPV and CPPV may counteract the development of sepsis-induced lung insufficiency in man. However, it must be emphasized that adequate cardiovascular support is essential in optimizing the treatment.     

Continuous positive pressure ventilation during epidural blockade--effects on cardiac output distribution

Background: It has been shown that when cardiac output (CO) decreases during continuous positive pressure ventilation (CPPV), its regional distribution adapts with a favouring of vital organs. Does epidural blockade modify this adaptation? Methods: Regional blood flows were assessed by the microsphere technique (15 μm) in 17 anaesthetised pigs during spontaneous breathing and CPPV with 8 cm H₂O end‐expiratory pressure (CPPV8) before and after epidural blockade. The block was induced at either the Th_6–7 (Thep) or the L₆–S₁ (Lep) level with 1 ml of lidocaine 40 mg · ml^?1. Results: When Lep was combined with CPPV8, mean arterial pressure and CO decreased significantly, and they decreased even more when combined with Thep. In contrast, the relative perfusion of the central nervous system, heart and kidneys remained stable during the four conditions studied. The adrenal perfusion during CPPV8 was obviated by epidural blockade. The absolute and relative perfusion of the skeletal muscle decreased during epidural blockade. The administered doses of epidural lidocaine did not affect blood flow in the spinal cord. Conclusions: The locally mediated nutritive vasoregulation of vital organs outweighed the sympathetic blockade induced by epidural blockade. During Thep blockade the animals were less capable of responding to the haemodynamic changes induced by CPPV8, probably due to the blockade of the cardiac part of the sympathetic nervous system.     

持续正压通气评分在早期诊断新生儿肺出血中的临床意义

目的　探讨持续正压通气 (CPPV)评分标准在新生儿肺出血早期诊断中的意义。方法　用回顾性分析方法分析我院 10 0例新生儿肺出血的病因 ,并使用CPPV的标准评分 ,判断CPPV分值与肺出血发生的关系。结果　本组 10 0例患儿均存在CPPV分值的改变。肺出血严重程度及预后与CPPV分值密切相关。肺出血CPPV评分值≤ 3分 30例均治愈 ,4～ 6分 5 3例 ,治愈率为 18 86 % ,好转率为 5 6 6 % ,病死率为 2 4 5 % ,≥ 7分者 17例均死亡。肺出血严重程度及预后与CPPV分值密切相关。临床资料分析提示缺氧和感染是新生儿肺出血的重要原因。结论　使用新生儿肺出血CPPV评分标准有助早期诊断肺出血 ,以指导临床治疗 ,降低肺出血病死率     

Repetitive Episodic Isolated Vertigo in a Patient with Cerebellar Infarction

Isolated vertigo is an important symptom of posterior circulation stroke. It has been reported that 11.3% of patients with isolated vertigo have a stroke and that most lesions are located in the cerebellum, particularly in the posterior inferior cerebellar artery. We report the case of a 63-year-old man with multiple atherosclerotic risk factors and atrial fibrillation who showed repeated episodes of isolated vertigo. His repeated vertigo was short-lasting and was often triggered by body position, mimicking benign paroxysmal positional vertigo. Cranial computed tomography on the third hospital day showed left cerebellar infarction within the territory of the posterior inferior cerebellar artery. The vertigo was ameliorated on the fifth hospital day and warfarin was prescribed for secondary prevention. Clinicians should pay special attention to cases in which a patient presents isolated vertigo, even if it shows transient recurrence or is triggered by a positional change, especially in patients with multiple cerebrovascular risk factors.