Tracheal intubation in critically ill patients: a comprehensive systematic review of randomized trials

Mechanical ventilation in patients with acute ischaemic stroke: from pathophysiology to clinical practice

Most patients with ischaemic stroke are managed on the ward or in specialty stroke units, but a significant number requires higher-acuity care and, consequently, admission to the intensive care unit. Mechanical ventilation is frequently performed in these patients due to swallowing dysfunction and airway or respiratory system compromise. Experimental studies have focused on stroke-induced immunosuppression and brain-lung crosstalk, leading to increased pulmonary damage and inflammation, as well as reduced alveolar macrophage phagocytic capability, which may increase the risk of infection. Pulmonary complications, such as respiratory failure, pneumonia, pleural effusions, acute respiratory distress syndrome, lung oedema, and pulmonary embolism from venous thromboembolism, are common and found to be among the major causes of death in this group of patients. Furthermore, over the past two decades, tracheostomy use has increased among stroke patients, who can have unique indications for this procedure—depending on the location and type of stroke—when compared to the general population. However, the optimal mechanical ventilator strategy remains unclear in this population. Although a high tidal volume (V_T) strategy has been used for many years, the latest evidence suggests that a protective ventilatory strategy (V_T = 6–8 mL/kg predicted body weight, positive end-expiratory pressure and rescue recruitment manoeuvres) may also have a role in brain-damaged patients, including those with stroke. The aim of this narrative review is to explore the pathophysiology of brain-lung interactions after acute ischaemic stroke and the management of mechanical ventilation in these patients.

Videolaryngoscopy in critically ill patients

Intubation is frequently required for patients in the intensive care unit (ICU) but is associated with high morbidity and mortality mainly in emergency procedures and in the presence of severe organ failures. Improving the intubation procedure is a major goal for all ICU physicians worldwide, and videolaryngoscopy may play a relevant role.

Videolaryngoscopes are a heterogeneous entity, including Macintosh blade-shaped optical laryngoscopes, anatomically shaped blade without a tube guide and anatomically shaped blade with a tube guide, which might have theoretical benefits and pitfalls. Videolaryngoscope/videolaryngoscopy improves glottis view and allows supervision by an expert during the intubation process; however, randomized controlled trials in the ICU suggest that the systematic use of videolaryngoscopes for every intubation cannot yet be recommended, especially in non-expert hands. Nevertheless, a videolaryngoscope should be available in all ICUs as a powerful tool to rescue difficult intubation or unsuccessful first-pass laryngoscopy, especially in expert hands.

The use of associated devices such as bougie or stylet, glottis view needed (full vs incomplete) and patient position during intubation (ramped, sniffed position) should be further evaluated. Future trials will better define the role of videolaryngoscopy in ICU.

Errors in search strategies used in systematic reviews and their effects on information retrieval

OBJECTIVES

Errors in search strategies negatively affect the quality and validity of systematic reviews. The primary objective of this study was to evaluate searches performed in MEDLINE/PubMed to identify errors and determine their effects on information retrieval.

METHODS

A PubMed search was conducted using the systematic review filter to identify articles that were published in January of 2018. Systematic reviews or meta-analyses were selected from a systematic search for literature containing reproducible and explicit search strategies in MEDLINE/PubMed. Data were extracted from these studies related to ten types of errors and to the terms and phrases search modes.

RESULTS

The study included 137 systematic reviews in which the number of search strategies containing some type of error was very high (92.7%). Errors that affected recall were the most frequent (78.1%), and the most common search errors involved missing terms in both natural language and controlled language and those related to Medical Subject Headings (MeSH) search terms and the non-retrieval of their more specific terms.

CONCLUSIONS

To improve the quality of searches and avoid errors, it is essential to plan the search strategy carefully, which includes consulting the MeSH database to identify the concepts and choose all appropriate terms, both descriptors and synonyms, and combining search techniques in the free-text and controlled-language fields, truncating the terms appropriately to retrieve all their variants.

Evaluation of the laryngoscopy view using the modified Cormack-Lehane scale during tracheal intubation in an intensive care unit. A prospective observational study

BACKGROUND AND OBJECTVIES

Tracheal intubation in the Intensive Care Unit is associated with a high incidence of difficult intubation and complications. This may be due to a poor view of the glottis during direct laryngoscopy. The aim of this study is to determine if there is a relationship between laryngoscopy view using the modified Cormack-Lehane scale with the incidence of difficult intubation and complications.

METHODS

All patients who were subjected to tracheal intubated with direct laryngoscopy in the Intensive Care Unit over a 45 month period were included in the study. In all patients, an evaluation was made of the laryngoscopy view using the modified Cormack-Lehane scale, as well as the technical difficulty (number of intubations at first attempt, operator-reported difficulty, need for a Frova introducer), and the incidence of complications (hypotension, hypoxia, oesophageal intubation).

RESULTS

A total of 360 patients were included. When the grade of the modified Cormack-Lehane scale was increased from 1 to 4, the incidence of first success rate intubation decreased (1: 97%, 2a: 94%, 2b: 80%, 3: 60%, 4: 0%, p<.001), the incidence of moderate and severe difficulty intubation increased (1: 2%, 2a: 4%, 2b: 36%, 3: 77%, 4: 100%, p<.001.), as well as the need for a Frova guide (1: 7%, 2a: 8%, 2b: 45%, 3: 60%, 4: 100%, p<.001). When the grade of the modified Cormack-Lehane scale increased from 1 to 4, the incidence of hypoxia<90% increased (1: 20%, 2a: 20%, 2b: 28%, 3: 47%, 4: 100%, p=.0073), as well as hypoxia<80% (1: 11%, 2a: 10%, 2b: 12%, 3: 27%, 4: 100%, p=.00398). No relationship was observed between the incidence of hypotension and the grade of the modified Cormack-Lehane scale (p=ns).

CONCLUSIONS

During tracheal intubation in the Intensive Care Unit a close relationship was found between a poor laryngoscopy view using the modified Cormack-Lehane scale and a higher difficulty technique of intubation. A relationship was found between the incidence of hypoxia with a higher grade in the modified Cormack-Lehane scale. No relationship was found between hypotension and the modified Cormack-Lehane scale.