Overview of mechanical ventilatory support and management of patient- and ventilator-related responses

Activation of Automatic Tube Compensation Mode Attenuates Auto-PEEP in Chronic Obstructive Pulmonary Disease Patients

INTRODUCTION

Dynamic hyperinflation in chronic obstructive pulmonary disease (COPD) results in intrinsic positive end-expiratory pressure (auto-PEEP). Automatic tube compensation (ATC) is used to increase airway pressure in COPD and overcome endotracheal tube (ETT)-imposed respiratory workload. We aim to investigate effects of ATC activation on auto-PEEP decrease in COPD.

METHODS

ATC was activated three times a day (1 min duration) in the morning, evening, and night shift. Auto-PEEP was measured for the 1 min period (every 6 s) following ATC activation. Linear mixed model (LMM) was used to measure changes in auto-PEEP and compare with baseline value. Age, gender, and COPD types were inserted in model as covariates and analyzed using SPSS.

RESULTS

A total of 60 patients including COPD (n = 40) and COPD with exacerbation (n = 20) were included. Compared with exacerbated COPD, baseline auto-PEEP in COPD was significantly lower in morning (p = 0.011), evening (p = 0.043), and night shift (p = 0.007). After ATC activation, auto-PEEP decreased significantly in COPD in morning, evening, and night (p = 0.001), but magnitude of this decrease was notably larger in COPD than in exacerbated COPD (p = 0.001). Moreover, there was a significant relationship between COPD exacerbation and changes in auto-PEEP in morning (β = -0.27, p = 0.001), evening (β = -0.16, p = 0.001), and night (β = -0.26, p = 0.001).

CONCLUSION

The activation of ATC mode in COPD patients under mechanical ventilation could decrease the value of auto-PEEP. Nevertheless, COPD patients with an exacerbation appear to benefit less from ATC activation.

Design of a Clinical Practice Guideline in Nurse-Led Ventilator-Weaning for Nursing Training

Cardiothoracic intensive care unit (CICU) nurses have shared the role and responsibility for ventilator-weaning to expedite decision-making in patient care. However, the actions taken are based on individual's unstructured training experience as there is no clinical practice guideline (CPG) for nurses in Malaysia. Hence, this study aims to design a CPG for the process of weaning from mechanical ventilation (MV) for a structured nursing training in a CICU at the National Heart Institute (Institut Jantung Negara, IJN) Malaysia. The Fuzzy Delphi Method (FDM) was employed to seek consensus among a panel of 30 experts in cardiac clinical practice on the guidelines. First, five experts were interviewed and their responses were transcribed and analyzed to develop the items for a FDM questionnaire. The questionnaire, comprising of 73 items, was distributed to the panel and their responses were analyzed for consensus on the design of the CPG. The findings suggested that the requirements expected for the nurses include: (a) the ability to interpret arterial blood gases, (b) knowledge and skills on the basics of mechanical ventilation, and (c) having a minimum 1-year working experience in the ICU. On the other hand, the CPG should mainly focus on developing an ability to identify criteria of patient eligible for weaning from MV. The learning content should focus on: (a) developing the understanding and reasoning for weaning and extubating and (b) technique/algorithm for extubating and weaning. Also, the experts agreed that the log book/competency book should be used for evaluation of the program. The CPG for structured nursing training at IJN in the context of the study is important for developing the professionalism of CICU nurses in IJN and could be used for training nurses in other CICUs, so that decision for ventilator-weaning from postcardiac surgery could be expedited.

Lung physiology and controlled exposure study design

Controlled human inhalation exposure ( CHIE) studies provide a unique opportunity to conduct formal experiments to examine the human health effects of airborne pollutants. Lung function, easily measured using spirometry, is a common physiological variable often utilized in these studies. By design, CHIE studies only induce mild and reversible acute effects, which may or may not predict adverse effects that may develop under chronic exposure conditions. There is substantial inter- and intra-individual variability in functional capacity and symptoms such as chest tightness and dyspnea, which are complex variables that are affected by individual perception, physiological lung impairment, and other variables (e.g., concomitant health conditions, and level of conditioning/fitness). Thus, the design of the CHIE study and physiological and environmental factors of study participants can affect each CHIE study's results. Researchers can address many of these critical issues in the problem formulation phase of CHIE studies, utilizing existing information on the expected effects of the substance of interest and possible modes of action. Thoughtful design and interpretation of CHIE studies will increase their utility for evaluating and setting environmental health policy.

Design and simulation of AI-based low-cost mechanical ventilator: An approach

In this situation of COVID 19, many people are being exposed to coronavirus, resulting in difficulty in breathing and a drop in oxygen percentage of blood. A mechanical ventilator is playing a vital role in tackling this situation but the ventilation process is neither readily available nor affordable. The idea behind this work is to propose a simplified design of a mechanical ventilator to reduce the cost and automate the Mechanical ventilation process. The simplified design, it's working, and required components are elaborated in this paper. The simulation of the proposed design is made in MATLAB/Simulink platform which is also discussed below. Taking into account the work done in the area of cost reduction of the mechanical ventilation process, the mechanical ventilator with a simplified design comprising of compressed air and oxygen source is being considered. The parameters considered for mechanical ventilation are positive end-expiratory pressure (PEEP), pressure wave, respiratory rate (RR), tidal volume, etc. These parameters of oxygen and air mixture are to be controlled with the help of electronic devices which are pressure regulator, solenoid valve, flow sensor, proportional valve, microprocessor, etc depending upon the condition of patient and type of disease. Simulation results are promising and precise which allows the study on ventilator model without jeopardizing the life of human subjects as in clinical approach and hides the complexity of computational models from the user. Furthermore, advancements in this model are done by the machine learning approach.

Communication with invasive mechanically ventilated patients and the use of alternative devices: integrative review

BACKGROUND

Communication with patients has always been a major concern in nursing care. Invasive mechanically ventilated (IMV) patients suffer from a communication barrier due to the presence of the endotracheal tube (ETT), which makes them unable to communicate through speech.

AIM

The purpose of this review is to examine available evidence regarding existing knowledge, skills, perceptions and barriers to IMV patient communication in order to guide the development of strategies that enhance effective communication with these patients.

METHODS

A review of the published literature was conducted between January 2010 and December 2016.

RESULTS

The literature support clear and concise communication in all areas of care, especially when patients suddenly become speechless. Invasive mechanically ventilated patients want to be heard, have control over their treatment and contribute to decisions concerning their health.

CONCLUSION

There is a need for the establishment of an effective nurse -patient communication strategy, which may include determining the mode of communication used by the patient, waiting and giving time to allow a patient to participate in the communication, confirming the message that was communicated with a patient himself/ herself, and the use of assistive and augmented communication to support comprehension when needed.

"Sedation is tricky": A qualitative content analysis of nurses' perceptions of sedation administration in mechanically ventilated intensive care unit patients

INTRODUCTION

Critical care nurses are responsible for administering sedative medications to mechanically ventilated patients. With significant advancements in the understanding of the impact of sedative exposure on physiological and psychological outcomes of ventilated patients, updated practice guidelines for assessment and management of pain, agitation, and delirium in the intensive care unit were released in 2013. The primary aim of this qualitative study was to identify and describe themes derived from critical care nurses' comments regarding sedation administration practices with mechanically ventilated patients.

METHODS

This is a qualitative content analysis of secondary text data captured through a national electronic survey of members of the American Association of Critical-Care Nurses. A subsample (n = 67) of nurses responded to a single, open-ended item at the end of a survey that evaluated nurses' perceptions of current sedation administration practices.

FINDINGS

Multiple factors guided sedation administration practices, including individual patient needs, nurses' synthesis of clinical evidence, application of best practices, and various personal and professional practice perspectives. Our results also indicated nurses desire additional resources to improve their sedation administration practices including more training, better communication tools, and adequate staffing.

CONCLUSIONS

Critical care nurses endorse recommendations to minimise sedation administration when possible, but a variety of factors, including personal perspectives, impact sedation administration in the intensive care unit and need to be considered. Critical care nurses continue to encounter numerous challenges when assessing and managing sedation of mechanically ventilated patients.

Ventilation of Nonparalyzed Patients Under Anesthesia with Laryngeal Mask Airway, Comparison of Three Modes of Ventilation: Volume Controlled Ventilation, Pressure Controlled Ventilation, and Pressure Controlled Ventilation-volume Guarantee

BACKGROUND

Pressure controlled ventilation (PCV) is the preferable mode of ventilation of nonparalyzed patients undergoing anesthesia with laryngeal mask airway (LMA) as compared to volume controlled ventilation (VCV) and spontaneously breathing patient. In this study, we compared the PC-volume guarantee (PC-VG) mode of ventilation with VCV and PCV modes.

MATERIALS AND METHODS

A total of 30 patients, American Society of Anesthesiologists (ASA) physical status Classes I and II, scheduled for elective surgery under general anesthesia with a classic LMA were ventilated, subsequently, with the three modes of ventilation: VCV, PCV, and PC-VG for 10 min each mode. Tidal volume set for all patients was 8 ml/kg of ideal body weight. Parameters measured with modes of ventilation include peak inspiratory pressure (PIP), compliance, measured tidal volume, O₂ saturation, end-tidal CO₂, and presence of an oropharyngeal leak.

RESULTS

The PIP was significantly higher with the application of VCV mode of ventilation than PCV and PC-VG modes. The compliance was significantly lower when using the mode of ventilation VCV than PCV and PC-VG. The PIP and the compliance were not statistically different between the PCV and PC-VG modes of ventilation.

CONCLUSIONS

Ventilation of nonparalyzed patients with LMA under anesthesia with PC-VG is advantageous over VCV in reducing PIP and increasing lung compliance. No difference was noted between PCV and PC-VG in ASA Classes I or II under the adequate depth of anesthesia in patients with normal pulmonary function.

Differential diagnosis of high peak airway pressures

BACKGROUND

The sickest patients often require mechanical ventilation. Although mechanical ventilation is often a lifesaving intervention for many, it can also have life-threatening complications. Monitoring a patient on mechanical ventilation requires skill and prompt troubleshooting to ensure its proper function. The high peak airway pressure (HPAP) alarm is one of the most common alarms. It is critically important that clinicians understand the pathophysiology of the lung and the various causes behind the alarm and have a working differential diagnosis for the causes of HPAPs. The differential diagnosis for HPAP is extensive but can be managed quickly and effectively if you follow a systematic approach.

OBJECTIVES AND METHODS

In this article, we aim to describe the basics of respiratory mechanics that contribute to HPAP alarms and describe concepts such as airway resistance, lung compliance, peak airway pressures, and plateau pressures. This is followed by a systematic approach to diagnosing the cause of the HPAP alarm.

DISCUSSION

The list of probable causes of HPAP is extensive. Many causes may be overlooked when there is not a clear understanding of its meaning and potential danger. Providing this algorithm gives relevance and importance to understanding the HPAP alarm and provides essential information for troubleshooting potentially dangerous situations.

[Tolerance of endotracheal tubes in patients on mechanical ventilation]

BACKGROUND

Modern concepts for sedation and analgesia and guidelines recommend light analgesia and sedation, so that patients on mechanically ventilation are more awake, compared to previous concepts. Hence, these patients are more alert and able to experience their situation on the ventilator and their endotracheal tube (ETT).

PROBLEM

There is currently no convincing evidence of how patients tolerate the tube under present conditions, which interventions could help them, or whether they want to be sedated deeper because of the tube. Based upon our own observations, a broad range of reactions are possible.

PURPOSE

The tolerance of the ETT in intensive care patients was explored.

METHOD

A systematic literature research without time constraints in the databases PubMed and CINAHL was performed. Included were quantitative and qualitative studies written in German or English that investigated tolerance of the ETT in adult intensive care patients. Excluded were anesthetic studies including in- and extubation immediately before and after operations.

RESULTS

Of the 2348 hits, 14 studies were included, including 4 qualitative studies about the experience of intensive care, 8 quantitative studies including 2 randomized controlled studies, and 2 studies with a mixed approach. Within the studies different aspects could be identified, which may in- or decrease the tolerance of an ETT. Aspects like breathlessness, pain during endotracheal suctioning and inability to speak decrease the tolerance. Information, the presence of relatives and early mobilization appear to increase the tolerance.

CONCLUSION

Tolerance of the ETT is a complex phenomenon. A reflected and critical evaluation of the behavior of the patient with an ETT is recommended. Interventions that increase the tolerance of the ETT should be adapted to the situation of the patient and should be evaluated daily.

Optimal management of the critically ill: anaesthesia, monitoring, data capture, and point-of-care technological practices in ovine models of critical care

Animal models of critical illness are vital in biomedical research. They provide possibilities for the investigation of pathophysiological processes that may not otherwise be possible in humans. In order to be clinically applicable, the model should simulate the critical care situation realistically, including anaesthesia, monitoring, sampling, utilising appropriate personnel skill mix, and therapeutic interventions. There are limited data documenting the constitution of ideal technologically advanced large animal critical care practices and all the processes of the animal model. In this paper, we describe the procedure of animal preparation, anaesthesia induction and maintenance, physiologic monitoring, data capture, point-of-care technology, and animal aftercare that has been successfully used to study several novel ovine models of critical illness. The relevant investigations are on respiratory failure due to smoke inhalation, transfusion related acute lung injury, endotoxin-induced proteogenomic alterations, haemorrhagic shock, septic shock, brain death, cerebral microcirculation, and artificial heart studies. We have demonstrated the functionality of monitoring practices during anaesthesia required to provide a platform for undertaking systematic investigations in complex ovine models of critical illness.

Decreasing accidental mortality of ventilator-dependent children at home: a call to action

An estimated 8,000 children in the United States are dependent on mechanical ventilation at home. Despite technological advances for home monitoring of ventilated patients, the preventable death rate among these children has not changed significantly during the last 2 decades. Analysis of the data indicate that the primary causes of preventable death in ventilator-dependent children at home are inadequate training, improper response, and a lack of vigilance by the clinicians who care for them.

Achieving quality patient-ventilator management: advancing evidence-based nursing care

This article presents suggestions for nurses to gain skill, competence, and comfort in caring for critically ill patients receiving mechanical ventilatory support, with a specific focus on education strategies and building communication skills with these challenging nonverbal patients. Engaging in evidence-based practice projects at the unit level and participating in or leading research studies are key ways nurses can contribute to improving outcomes for patients receiving mechanical ventilation. Suggestions are offered for evidence-based practice projects and possible research studies to improve outcomes and advance the science in an effort to achieve quality patient-ventilator management in intensive care units.