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Last week we focused on prevention of post-op pneumonia (see our June 21, 2022 Patient Safety Tip of the Week “Preventing Post-op Pneumonia”). But another form of hospital-acquired pneumonia that is even more frequent is that which is seen in patients admitted with a variety of neurological conditions. So, timely is a recent review article on pneumonia in nervous system injuries (Erfani 2022). Pneumonia is a significant contributor to mortality and prolonged lengths of stay in patients with neurological conditions.
Erfani and colleagues conducted an extensive literature search and review on the topic. They note that over a third of patients admitted to neurointensive care units (neuro-ICUs) for a period exceeding 48 hours develop nosocomial infections with pneumonia being the most common type of infection. Ventilator-associated pneumonia is frequent in those patients.
But pneumonia also occurs frequently as a complication in neurological patients not on ventilators or in neuro-ICU’s.
They identify risk factors for hospital-acquired pneumonia (HAP) in general: Glasgow Coma Scale (GCS) less than 8, mechanical ventilation, impaired airway reflexes, supine positioning, aspiration, preexisting diseases like chronic obstructive pulmonary disease (COPD), burns, prolonged ICU stay, use of positive end expiratory pressure (PEEP) during mechanical ventilation, high disease severity, multiple organ dysfunction, older age, prior administration of antibiotics, malnutrition, use of the nasogastric tube, use of paralytic agents, male gender, enteral feeding, immunosuppression, and trauma.
But they note that the nature of the critical conditions in CNS leads to higher susceptibility to developing pneumonia, due to factors such as brain injury-induced immune dysregulation and immunosuppression, high prevalence of dysphagia, and interventions such as placement of external ventricular drains (EVDs).
We have always focused on dysphagia and impairment of consciousness, with consequent aspiration, as the major mechanism for pneumonia in neurological inpatients. However, Erfani and colleagues point out some interesting contributing factors that we had not been aware of. One such contributing factor is brain injury-induced immune dysregulation. That is caused primarily caused by an elevated inflammatory response which leads to central and peripheral production of chemokines, proinflammatory cytokines, and cell adhesion molecules in these patients. Development of the inflammatory response is a crucial part of clearing cellular debris in the CNS following an injury. But chronic and prolonged inflammation response can lead to dysregulation in the immune system. Such is commonly seen in acute events, like trauma, brain surgery, subarachnoid hemorrhage (SAH), or spinal cord injury. When it occurs after stroke, it is named stroke-induced immunodepression syndrome (SIDS). SIDS is considered to be biphasic, the first phase starting as soon as 12 hours after the initial injury with early transient activation lasting up to 24 hours, and a second phase consisting of a systemic immunodepression that can last for several weeks. They also discuss the immunosuppression that may occur due to prolonged catecholamine release which accompanies many of these conditions.
They go on to discuss pneumonia in a variety of neurological conditions.
Known risk factors for stroke-associated pneumonia (SAP) include dysphagia, higher National Institutes of Health Stroke Scale (NIHSS), non-lacunar basal-ganglia infarction, age, large middle cerebral artery (MCA) infarction, multiple hemispheric or vertebrobasilar infarction, mechanical ventilation on admission, and impaired vigilance. The presence of intubation also increases the risk of pneumonia independently of the presence of known aspiration. Conversely, a lower risk of SAP was seen in small-vessel occlusions (We, however, would remind all that bilateral lacunar infarcts, which we often refer to as the “double whammy” syndrome, may lead to pseudobulbar palsy that increases the risk of aspiration). They also note that brain injury-induced immunosuppression may be more common with more massive strokes and strokes impacting certain structures, such as the insular cortex.
They, of course, do go on to discuss dysphagia and impaired consciousness as major factors contributing to development of pneumonia after stroke.
In terms of pneumonia prevention, they do stress that addressing dysphagia is one of the most important interventions. It is critical that, in patients with stroke or the other mentioned neurological conditions, that an assessment of swallowing be performed prior to giving food or anything via mouth. Improved screening for dysphagia and nurse education has been shown to decrease the risk of pneumonia as was demonstrated in a single-center study which showed a decrease in pneumonia prevalence from 6.5% to 2.8% after the screening and education changes were implemented.
Early administration of prophylactic antibiotics has not been shown to be effective in decreasing mortality or functional outcome in these patients and is not indicated. They also note that oropharyngeal decontamination with povidone-iodine has not been effective in the prevention of ventilator-associated pneumonia (VAP) in patients with critical brain injuries or cerebral hemorrhages.
The timing of tracheostomy placement in such patients who require continuous ventilation does not seem to affect the mortality rate but, in some studies, early tracheostomy placement may decrease the duration of ventilation. (Note that a just-published study (Bösel 2022) on the effect of early vs standard approach to tracheostomy among patients with severe stroke receiving mechanical ventilation showed no difference in the rate of survival without severe disability at 6 months. In that study, pneumonia within 48 hours of tracheostomy was more frequent in the early tracheostomy group but that did not reach statistical significance. There were no significant differences in the total duration of mechanical ventilation or ICU length of stay.)
Erfani and colleagues also discuss another potential prevention strategy: addressing brain injury-induced immunosuppression. Since this immunosuppression is mainly due to sympathetic nervous system activation, they discuss the potential use of β-adrenergic receptor blockers but caution that further assessment of β-blocker administration needs to be carried out in order for it to be confirmed as a routine choice for the prevention of pneumonia in NICU’s.
In our June 2022 What's New in the Patient Safety World column “Guideline Update: Preventing Hospital-Acquired Pneumonia” we discussed the 2022 update of “Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals” (Klompas 2022). That update was collaborative work of the Society for Healthcare Epidemiology (SHEA), the Infectious Diseases Society of America (IDSA), the American Hospital Association, the Association for Professionals in Infection Control and Epidemiology, and The Joint Commission, with input from multiple other organizations and societies.
That update included a new section on prevention of nonventilator hospital-acquired pneumonia (NV-HAP). That section notes there is actually a scant evidence base for strategies to prevent NV-HAP. This section emphasizes oral care, recognizing and managing dysphagia, early mobilization, and implementing multimodal approaches to prevent viral infections. Regarding diagnosis and management of dysphagia, the updated guideline had the following recommendations:
<![if !supportLists]>1. <![endif]>Early diagnosis and treatment of dysphagia may prevent NV-HAP, especially among neurologically impaired post-stroke patients.
<![if !supportLists]>2. <![endif]>Potential approaches to diagnose dysphagia include nurse-administered risk assessment tools, bedside functional evaluations of swallowing, video fluoroscopic study, and fiberoptic endoscopic examination.
<![if !supportLists]>3. <![endif]>Potential options to manage dysphagia include changes in method of pill administration, adjustments in consistencies of liquids and solids, supervision or assistance with meals, use of straws, and elevation of the head of bed while eating.
One surprising omission from the discussion of pneumonia in neurological conditions is OSA (obstructive sleep apnea). We know that OSA is common in acute stroke patients and some of the other conditions, and that OSA has been linked as a possible contributing factor to community-acquired pneumonia (Chiner 2016). It would certainly be of interest to see if OSA is a risk factor for development of pneumonia in these and other inpatient conditions.
For those that are interested, the Erfani review also discusses pneumonia is subarachnoid hemorrhage, brain traumatic injury, intracerebral hemorrhage, spinal cord injury, status epilepticus, neuromuscular diseases, and multiple sclerosis (MS) and demyelinating diseases. It also has sections on radiographic findings and treatment of pneumonia. The Erfani review has 139 references with links. We think you will find this very useful.
Erfani Z, Jelodari Mamaghani H, Rawling J, et al. Pneumonia in Nervous System Injuries: An Analytic Review of Literature and Recommendations. Cureus 2022; 14(6): e25616
Bösel J, Niesen W, Salih F, et al. Effect of Early vs Standard Approach to Tracheostomy on Functional Outcome at 6 Months Among Patients With Severe Stroke Receiving Mechanical Ventilation: The SETPOINT2 Randomized Clinical Trial. JAMA 2022; 327(19): 1899-1909
Klompas M, Branson R, Cawcutt K, et al.. Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals: 2022 Update. Infect Control Hosp Epidemiol 2022; 20: 1-27
Chiner E, Llombart M, Valls J, et al. Association between Obstructive Sleep Apnea and Community-Acquired Pneumonia. PloS One 2016; 11(4): e0152749
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