呼吸机撤离的循证基础[1]

ACCP-SCCM-AARC Evidence-Based Weaning Guideline
Recommendation 8:
Unless there is evidence of clearly irreversible disease , a patient who requires prolonged ventilatory support for respiratory failure should not be considered permanently ventilatordependent until 3 months of weaning attempts have failed.
ACCP-SCCM-AARC Evidence-Based Weaning Guideline
Recommendation 7: 1. Critical care practitioners should be familiar with facilities in their communities or units in their hospital that specialize in managing patients who suffer prolonged ventilator-dependence, and practitioners should stay abreast of peer-reviewed reports from such unit. 2. When medically stable enough for transfer, patients who have failed discontinuation attempts in the ICU should be transferred to facilities that have demonstrated success and safety in accommplishing ventilator discontinuation.
Mode
SIMV
Patient Work Adjusted By
Number of machine breaths supplied（the fewer the number of machine breaths，the more spontaneous breaths are require） Level of inspiratory pressure assistance with spontaneous efforts
ACCP-SCCM-AARC Evidence-Based Weaning Guideline
Recommendation 1: Patients receiving MV for respiratory failure should undergo a formal assessment of discontinuation potential if the following criteria are satisfied: Evidence of some reversal of the underlying cause of respiratory failure 1. Adequate oxygenation: PO2/FiO2>150-200 mmHg PEEP<58cmH2O, FiO2<0.4-0.5, pH>7.25 2. Hemodynamic stability as defined by the absence of clinically important hypotension and requiring no vasopressors or only low-dose vasopressors( dopamine or dobutamine < 5ug/kg/min) 3. Patient is able to initiate an inspiratory effort

SBT失败患者的处理
一旦SBT失败，有两个重要的问题必须回答 SBT失败的原因？能否纠正？ 失败后选择何种MV的方式？
1. 2.

1. 2.
SBT失败的原因
最常见的原因是呼吸系统机械力学异常 镇痛和镇静 液体平衡情况 支气管扩张剂 缺血性心脏病
3.
4. 5.
Modes of Partial Ventilatory Support
Brochard L, Am J Respir Crit Care Med 1994;150(4):896-903 Esteban A, N Engl J Med 1995;332(6):345-350
1. 2.
呼吸机撤离的指标(2类) 机械通气的指标( MVT, 氧合指数) 短时间自主呼吸的指标 ( VT, 吸气负压, 呼吸功, 浅快指数 f/VT )
长时间,认真, 反复进行SBT的评估所提供的信息 是最重要的




SBT可以引起呼吸肌的负荷增加和呼吸肌疲 劳, 常发生在SBT的早期, 因此SBT的前几分 钟应密切观查病情 SBT常作为筛查的方法, f/VT>105次/分表示 SBT失败 SBT至少持续30分钟,最多不超过120分钟

1.
机械通气患者病情稳定后的处理原则
计划性脱机
首都医科大学附属复兴医院 席修明 2004.9.23 昆明

文献报道 内科ICU机械通气的病人中,医务人员 42%的时间用于呼吸机的撤离
Esteban A, Chest 1994; 106(4) 11881193


目前所有的相关指标都无法帮助我们作出准确 的撤机决定 Stroetz RW 应用临床指标判断脱机的可能性， 敏感性为35% （17名判断脱机者中6名成功）， 特异性79% （14名判断不能脱机者，有11名符合）
Stroetz RW, Am J Respir Crit Care Med 1995;152(3):1034-1040


两个大样本的研究表明, 患者病情稳定或好转后, 约2/3可以进行撤机的患者 医生仍没认识到应作 自主呼吸实验 (SBT) 结论: 寻找临床情况稳定或好转的证据是判断脱 机与否的关键第一步.
ACCP-SCCM-AARC Evidence-Based Weaning Guideline
Recommendation 9: With a patient who requires prolonged ventilation the weaning should be slowpaced and should include gradually lengthening SBTs.
ACCP-SCCM-AARC Evidence-Based Weaning Guideline
Recommendation 6: Weaning/discontinuation protocols designed for nonphysician clinicians should be developed and implemented by ICU. Protocols should aim to optimize sedation.
ACCP-SCCM-AARC Evidence-Based Weaning Guideline
Recommendation 3: With patients whose ventilatory support has been successfully discontinued, the decision of whether to remove the artificial airway should be based on assessment of airway patency and the patient’s ability to protact the airway
ACCP-SCCM-AARC Evidence-Based Weaning Guideline
Recommendation 2:
1.
2. 3.
4.
Formal discontinuation assessments should be done during spontaneous breathing rather than while the patient is still receiving substantial ventilation support. An initial brief period of spontaneous breathing can be used to assess the patient’s ability to do a formal SBT. Criteria to assess patient tolerance during SBT are the respiratory pattern, adequacy of gas exchange, hemodynamic stability, and subjective comfort. Patients who tolerate a 30-120min SBT should promptly be considered for ventilator-discontinuation
PSV
SIMV+SV Volume-support
PSV with a guaranteed minimum Vt （ PSV level adjust automatically according to the clinician-set Vt） PSV with a guaranteed minimum Vt（additional flow is supplied at end inspiration SIMV with a guaranteed minute ventilation （machine breath rate automatically adjusts according to clinician ventilation setting）