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.     

Principles of artificial ventilation

The application of intermittent positive pressure ventilation (IPPV) during the 1952 Copenhagen polio epidemic led to the development of the world’s first intensive care unit. The requirement for ventilatory support is the most common indication for intensive therapy unit (ITU) admission and is a defining feature of the specialty. Ventilator technology continues to develop and there are many ways to deliver IPPV. The variety of modes of ventilation is increasingly complex and expanding, without evidence that any one mode is associated with improved outcome. Ventilatory support is part of the treatment for a range of conditions including acute respiratory failure, raised intracranial pressure (ICP) and circulatory shock. Ventilator-associated lung injury is reduced by using low tidal volumes and limiting plateau airway pressure to less than 30 cmH₂O. Prolonged artificial ventilation has an associated morbidity and mortality and thus should be reviewed by an expert clinician on a daily basis. Weaning aims to identify those patients who will be able to breathe spontaneously. Protocols exist to facilitate timely extubation without the need for re-intubation.     

Fifteen years of using a second stage protein substitute for weaning in phenylketonuria: a retrospective study

Background

In phenylketonuria (PKU), during weaning, it is necessary to introduce a second stage phenylalanine (Phe)‐free protein substitute (PS) to help meet non‐Phe protein requirements. Semi‐solid weaning Phe‐free PS have been available for >15 years, although no long‐term studies have reported their efficacy.

Methods

Retrospective data from 31 children with PKU who commenced a weaning PS were collected from clinical records from age of weaning to 2 years, on: gender; birth order; weaning age; anthropometry; blood Phe levels; age commenced and dosage of weaning PS and Phe‐free infant L‐amino acid formula; natural protein intake; and issues with administration of PS or food.

Results

Median commencement age for weaning was 17 weeks (range 12–25 weeks) and, for weaning PS, 20 weeks (range 13–37 weeks). Median natural protein was 4 g day^?1 (range 3–11 g day^?1) and total protein intake was >2 g kg^?1 day^?1 from weaning to 2 years of age. Children started on 2–4 g day^?1 protein equivalent (5–10 g day^?1 of powder) from weaning PS, increasing by 0.2 g kg^?1 day^?1 (2 g day^?1) monthly to 12 months of age. Teething and illness adversely affected the administration of weaning PS and the acceptance of solid foods. Altogether, 32% of children had delayed introduction of more textured foods, associated with birth order (firstborn 80% versus 38%; P = 0.05) and food refusal when teething (80% versus 29%; P = 0.02).

Conclusions

Timing of introduction of solid foods and weaning PS, progression onto more textured foods and consistent feeding routines were important in aiding their acceptance. Any negative behaviour with weaning PS was mainly associated with food refusal, teething and illness. Parental approach influenced the acceptance of weaning PS.

     

No difference in self‐reported frequency of choking between infants introduced to solid foods using a baby‐led weaning or traditional spoon‐feeding approach

Background

Baby‐led weaning (BLW) where infants self‐feed family foods during the period that they are introduced to solid foods is growing in popularity. The method may promote healthier eating patterns, although concerns have been raised regarding its safety. The present study therefore explored choking frequency amongst babies who were being introduced to solid foods using a baby‐led or traditional spoon‐fed approach.

Methods

In total, 1151 mothers with an infant aged 4–12 months reported how they introduced solid foods to their infant (following a strict BLW, loose BLW or traditional weaning style) and frequency of spoon‐feeding and puree use (percentage of mealtimes). Mothers recalled if their infant had ever choked and, if so, how many times and on what type of food (smooth puree, lumpy puree, finger food and specific food examples).

Results

In total, 13.6% of infants (n = 155) had ever choked. No significant association was found between weaning style and ever choking, or the frequency of spoon or puree use and ever choking. For infants who had ever choked, infants following a traditional weaning approach experience significantly more choking episodes for finger foods (F_2,147 = 4.417, P = 0.014) and lumpy purees (F_2,131 = 6.46, P = 0.002) than infants following a strict or loose baby‐led approach.

Conclusions

Baby‐led weaning was not associated with increased risk of choking and the highest frequency of choking on finger foods occurred in those who were given finger foods the least often. However, the limitations of noncausal results, a self‐selecting sample and reliability of recall must be emphasised.     

标准化流程撤机智能软件在慢性阻塞性肺疾病急性加重机械通气患者撤机中的应用效果

目的探讨标准化流程撤机智能软件在慢性阻塞性肺疾病急性发作(AECOPD)机械通气患者撤机中的应用效果。方法选取2018年6月至2019年6月入住我院EICU的68例AECOPD机械通气患者,按照智能软件使用时间将患者分成两组,其中将2018年6—12月根据医生经验主导撤机的32例患者设为对照组,另将2019年1—6月采用标准化流程智能软件撤机的36例患者设为观察组,比较两组患者机械通气时间、撤机成功率、呼吸机相关性肺炎(VAP)发生率、住院时间、住院费用、患者舒适度情况。结果 (1)两组患者入组时的一般资料、GCS评分以及危重症评分等比较,差异无统计学意义(P0.05);(2)观察组机械通气时间、住院时间均短于对照组,差异有统计学意义(P0.05);观察组VAP发生率及住院费用均低于对照组,差异有统计学意义(P0.05);而撤机成功率则高于对照组,差异有统计学意义(P0.05)。(3)观察组患者的舒适度评分显著优于对照组,差异有统计学意义(P0.05)。结论标准化流程撤机智能软件能规范AECOPD机械通气过程,系统评估患者病情,及时撤机,同时给予相应的撤机后序贯治疗,有助于机械通气患者的疾病转归及预后,提高患者住院期间的舒适度,改善护理结局,减少患者住院时间及费用,提高患者的生存质量,值得临床推广。     

机械通气患者的脱机（附85例分析）

分析了８５例机械通气患者恢复时的脱机过程。列举２例脱机困难者的处理。讨论了脱机患者的病理生理改变，脱机标准的掌握和营养支持与脱机的关系。认为脱机时机的掌握，脱机过程的调节，以及必要的营养支持有益于顺利脱机。     

Management of and indications for tracheostomy in care of the critically ill patient

Tracheostomy is a procedure that has evolved over many hundreds of years. In the 21st century, the majority of tracheostomies are now inserted by intensivists in the intensive care unit (ICU). Commonly performed to assist in weaning patients from mechanical ventilation, the procedure is performed using a percutaneous dilatational technique. Percutaneous tracheostomy can generally be performed safely in the ICU, although a number of contra-indications and complications do exist. Recent publications have highlighted weaknesses in the quality of care both in the immediate and longer term. Consequently, a number of organizations, based in the UK and internationally, have turned the focus in recent years to improving the quality of care delivered to these patients. Clinicians caring for patients with tracheostomies should not only be familiar with the indications, anatomy and insertion techniques, but also current guidance on routine care and the emergency management of complications.     

Practical ventilator management

Mechanical ventilation is a common invasive intervention in intensive care units. While respiratory failure remains the most common indication for mechanical ventilation, the application and indications of this intervention are far more variable. Ventilation causes marked alteration to human physiology and is associated with complications and iatrogenic injuries. This article highlights practical aspects of patient management during invasive ventilation.