急性呼吸窘迫综合征患者适应性支持通气的效果

目的 评价适应性支持通气（ASV）模式与间歇正压通气（IPPV）模式在急性呼吸窘迫综合征（ARDS）患者中的效果。方法 ARDS患者30例，年龄19—46岁，男18例，女12例，ASAⅢ或Ⅳ级。先应用IPPV模式，吸入氧浓度60％，PEEP为0，潮气量（VT）10ml／kg，吸呼比（I：E）1：2，维持8h后随机选择换用ASV或继续IPPV通气模式，通气时依次按0、5、10cm H2O增加PEEP，每一PEEP水平的通气时间为60min，在同样的分钟通气量的设置下，4h后更换另一种通气模式，仍按0,5、10cm H2O增加PEEP，每一PEEP水平的通气时间为60min。每个PEEP水平通气50min时，用Swan-Ganz导管、心电监测仪、呼吸机监测记录血液动力学、呼吸力学和氧代谢数据。结果 与IPPV模式比较，ASV模式下气道峰值压降低，肺动态顺应性（Cdyn）、动脉氧分压（PaO2）和氧供（DO2）增加（P〈0．05）。两种通气模式的血液动力学参数比较差异无统计学意义（P〉0．05）。结论 ASV模式比IPPV模式更有利于ARDS患者的通气治疗。     

Ventilatory support in the ICU

The requirement for ventilatory support using positive pressure ventilation to correct the blood-gas abnormalities associated with acute respiratory failure is the most common indication for ICU admission. Ventilatory support may also be indicated in the management of circulatory shock and raised intracranial pressure. Non-invasive ventilation describes the application of positive pressure ventilation with a face mask, avoiding the complications of tracheal intubation associated with conventional ventilatory support. The modern ICU ventilator provides a wide range of modes, although there is no evidence that any particular mode is associated with an improved outcome. Ventilator-induced lung injury is minimized by preventing lung over-distension with the use of appropriate tidal volumes and limiting plateau airway pressure to less than 30 cm H₂O. Prolonged ventilatory support is associated with a number of complications and readiness for discontinuation should be assessed on a daily basis. In a significant minority of patients, weaning ventilatory support proves to be a challenge and may reflect underlying chronic respiratory disease, left ventricular impairment or critical illness polyneuropathy/myopathy.     

Ventilatory support in the intensive care unit

This article focuses on a classification of modes of mechanical ventilation, the indications for and complications of invasive and non-invasive mechanical ventilation and the recent evidence on adjuncts to mechanical ventilation.     

Ventilatory support in the intensive care unit

This article focuses on a classification of modes of mechanical ventilation, the indications for and complications of invasive and non-invasive mechanical ventilation and adjuncts to mechanical ventilation.     

Ventilatory support in the intensive care unit

This article focuses on the functional features of positive-pressure ventilators, the modes of invasive and non-invasive mechanical ventilation, and the main ventilator settings. It also highlights the potential complications of mechanical ventilation, the basic principles of weaning, and the pathophysiological basis of patient-ventilator dyssynchrony.     

Ventilatory support in the intensive care unit

Mechanical ventilation is a crucial supportive intervention that allows time to facilitate investigations and provide definitive treatment in critically unwell patients. This article focuses on the various modes of respiratory support available, and the mechanical ventilation strategies used in specific disease processes. It also highlights the possible complications associated with mechanical ventilation and the adjuncts that can be used to aid oxygenation.     

Ventilatory support following open heart surgery

One thousand consecutive patients undergoing open heart surgical procedures were evaluated for the need for ventilation in the postoperative period. All cases of mitral valve replacement (237) and double valve replacement (85) were electively ventilated. Fifty-two other patients required ventilation for various reasons which included low cardiac output with inotropic support, ventricular arrhythmias, left atrial pressure above 18 mm Hg, bleeding, hypo or hyperthermia, unsatisfactory blood gases, neurological problems, overdosage of narcotics, incomplete reversal of relexants and flooded lungs at the end of operation. Twenty patients needed ventilation beyond 4 days. Prolonged ventilatory support was maintained with nasotracheal tube and only 3 patients required tracheostomy after 12 days for cerebral and pulmonary complications. The pulmonary complications encountered during postoperative ventilation were stiff lungs, copious secretions and bleeding in 20 patients.     

Protective ventilation of patients with ARDS

Editor—I read with interest the review article on protectiveventilation of patients with acute respiratory distress syndrome(ARDS).¹ In their comments on the use of prone ventilation inpatients with ARDS, the authors have quoted the study by     

Ventilatory support and primary closure of gastroschisis

Recent clinical reports suggest that the majority of neonates with gastroschisis are best managed with a silon pouch technique. Our results with primary closure and short-term ventilatory assistance show a survival rate equal to that of the silon pouch technique. In addition, multiple operations and the chances of complications related to the pouch are avoided. No complications relating to the ventilatory assistance were encountered. Better pediatric ventilators and improved pediatric respiratory management allow this technique to be used for gastroschisis now, whereas 10 years ago the complications ith neonatal ventilators may have outweighed the morbidity of the silon pouch.     

Endotoxemia and endotoxin tolerance in patients with ARDS

Background The significance of endotoxemia in man is controversial, induces cytokine release and stimulates the immune system. Exaggerated cytokine release of mononuclear cells was observed in acute lung injury/acute respiratory distress syndrome (ALI/ARDS). However, repetitive administration of endotoxin can cause tolerance. Objective To investigate endotoxemia, plasma TNFα, IL-1β, IL-6, the liberation capacity of those cytokines from mononuclear cells after LPS challenge (Δ values), and plasma antibodies to endotoxins and α-hemolysin of Staphylococcus aureus in ALI/ARDS. Design A prospective clinical study was conducted. Setting The study was carried out at the University Hospital Ulm, Ulm, Germany. Subjects The respondents were 23 patients with ALI/ARDS. Interventions ALI/ARDS was defined according to the American–European Consensus Conference on ARDS. Blood was collected periodically. Parameters were measured by LAL or ELISA. Results ARDS (P_aO₂/F_iO₂ < 200) revealed higher endotoxemia (0.22–0.46 [0.06–1.15] EU/mL vs 0.05–0.14 [0.02–0.63] EU/mL) than ALI (P_aO₂/F_iO₂ > 200) but lower ΔIL-6 (124–209 [10–1214] pg/mL vs 298–746 [5–1797] pg/mL), ΔTNFα (50–100 [6–660] pg/mL vs 143–243 [12–2795] pg/mL), and ΔIL-1 (2–3 [0–26] pg/mL vs 2–14 [0–99] pg/mL). Endotoxemia correlated negative with P_aO₂/F_iO₂ (r, −0.44 to −0.50). All patients presented antibodies to lipopolysaccharides and α-hemolysin, but the level did not correlate with P_aO₂/F_iO₂. Conclusions ALI/ARDS is associated with endotoxemia. The more severe the disease, the more intense is endotoxemia but the lower is the capacity of mononuclear cells to release cytokines (tolerance). Antibodies against Gram-positive and Gram-negative bacteria are detectable in the plasma but without relation to P_aO₂/F_iO₂.     

Ventilatory mechanics in patients with bronchiectasis starting in childhood

Landau, L. I., Phelan, P. D., and Williams, H. E. (1974).Thorax, 29, 304-312. Ventilatory mechanics in patients with bronchiectasis starting in childhood. The mechanics of ventilation have been studied in 69 children and young adults with bronchiectasis since childhood. Many were well with little disability and although symptoms had ameliorated in the second decade cough and sputum still persisted.     

Ventilatory strategies in septic patients

Background

Mortality in intensive care unit (ICU) patients is affected by multiple variables. The possible impact of the mode of ventilation has not yet been clarified; therefore, a secondary analysis of the “epidemiology of sepsis in Germany” study was performed. The aims were (1) to describe the ventilation strategies currently applied in clinical practice, (2) to analyze the association of the different modes of ventilation with mortality and (3) to investigate whether the ratio between arterial partial pressure of oxygen and inspired fraction of oxygen (PF ratio) and/or other respiratory variables are associated with mortality in septic patients needing ventilatory support.

Methods

A total of 454 ICUs in 310 randomly selected hospitals participated in this national prospective observational 1-day point prevalence of sepsis study including 415 patients with severe sepsis or septic shock according to the American College of Chest Physicians/Society of Critical Care Medicine criteria.

Results

Of the 415 patients, 331 required ventilatory support. Pressure controlled ventilation (PCV) was the most frequently used ventilatory mode (70.6 %) followed by assisted ventilation (AV 21.7 %) and volume controlled ventilation (VCV 7.7 %). Hospital mortality did not differ significantly among patients ventilated with PCV (57 %), VCV (71 %) or AV (51 %, p?=?0.23). A PF ratio equal or less than 300 mmHg was found in 83.2 % of invasively ventilated patients (n?=?316). In AV patients there was a clear trend to a higher PF ratio (204?±?70 mmHg) than in controlled ventilated patients (PCV 179?±?74 mmHg, VCV 175?±?75 mmHg, p?=?0.0551). Multiple regression analysis identified the tidal volume to pressure ratio (tidal volume divided by peak inspiratory airway pressure, odds ratio OR?=?0.94, 95 % confidence interval 95% CI?=?0.89–0.99), acute renal failure (OR?=?2.15, 95% CI?=?1.01–4.55) and acute physiology and chronic health evaluation (APACHE) II score (OR?=?1.09, 95% CI?=?1.03–1.15) but not the PF ratio (univariate analysis OR?=?0.998, 95 % CI?=?0.995–1.001) as independent risk factors for in-hospital mortality.

Conclusions

This representative survey revealed that severe sepsis or septic shock was frequently associated with acute lung injury. Different ventilatory modes did not affect mortality. The tidal volume to inspiratory pressure ratio but not the PF ratio was independently associated with mortality.     

The pulmonary physician in critical care. 8: Ventilatory management of ALI/ARDS

Current data relating to ventilation in ARDS are reviewed. Recent studies suggest that reduced mortality may be achieved by using a strategy which aims at preventing overdistension of lungs.     

Extracorporeal respiratory support and minimally invasive ventilation in severe ARDS

BACKGROUND: To evaluate the results of treatment of severe acute respiratory distress syndrome (ARDS) with extracorporeal life support (ECLS), minimal sedation and low pressure supported ventilation in adults. METHODS: Design and setting: observational study in a tertiary referral center, Intensive Care Unit, Astrid Lindgren Children's Hospital at Karolinska Hospital, Stockholm, Sweden. Patients: thirty-eight patients aged 17-61 years (mean 38) with severe ARDS. The Murray score of pulmonary injury averaged 3.5 (3.0-4.0) and the mean PaO2/FiO2 ratio was 47 (31-65). Intervention: the patients were treated with veno-venous or veno-arterial ECLS after failure of conventional respiratory therapy. A standard ECLS circuit with no heparinized surfaces was used. The patients were minimally sedated and received pressure-supported ventilation. High inspiratory pressures were avoided. RESULTS: 25 of the 38 patients survived (total survival rate 66%) after 2-57 days on ECLS (mean 17). Major surgical procedures were performed in several patients during bypass. CONCLUSIONS: A high survival rate can be obtained in adult patients with severe ARDS using ECLS, minimal sedation and pressure-supported ventilation with low inspiratory pressures. Surgical complications are amenable to surgical treatment during ECLS and bleeding problems can be controlled.