Future considerations in aspiration pneumonia in the critically ill patient: what is not known, areas for future research, and experimental methods

Temporary-permanent pacemakers are associated with better clinical and safety outcomes compared to balloon-tipped temporary pacemakers

BACKGROUND

Balloon Tipped Temporary Pacemakers (BTTP) are the most used temporary pacemakers; however, they are associated with a risk of dislodgement and thromboembolism. Recently, Temporary Permanent Pacemakers (TPPM) have been increasingly used. Evidence of outcomes with TPPM compared to BTTP remains scarce.

METHODS

Retrospective, chart review study evaluating all patients who underwent temporary pacemaker placement between 2014 and 2022 (N = 126) in the cardiac catheterization laboratory (CCL) at a level 1 trauma center. Primary outcome of this study is to evaluate the safety profile of TPPM versus BTTP. Secondary objectives include patient ambulation and healthcare utilization in patients with temporary pacemakers.

RESULTS

Both groups had similar baseline characteristics distribution including gender, race, and age at temporary pacemaker insertion (p > .05). Subclavian vein was the most common site of access for the TPPM cohort (89.0%) versus the femoral vein in the BTTP group (65.1%). Ambulation was only possible in the TPPM group (55.6%, p < .001). Lead dislodgement, venous thromboembolism, local hematoma, and access site infections were less frequently encountered in the TPPM group (OR = 0.23 [95% CI (0.10-0.67), p < .001]). Within the subgroup of patients with TPPM, 36.6% of the patients were monitored outside the ICU setting. There was no significant difference in the pacemaker-related adverse events among patients with TPPM based on their in-hospital setting.

CONCLUSION

TPPM is associated with a more favorable safety profile compared to BTTP. They are also associated with earlier patient ambulation and reduced healthcare utilization.

Gastric Residual Volume (GRV) and Gastric Contents Measurement by Refractometry

BACKGROUND

Traditional use of gastric residual volumes (GRVs), obtained by aspiration from a nasogastric tube, is inaccurate and cannot differentiate components of the gastric contents (gastric secretion vs delivered formula). The use of refractometry and 3 mathematical equations has been proposed as a method to calculate the formula concentration, GRV, and formula volume. In this paper, we have validated these mathematical equations so that they can be implemented in clinical practice.

METHODS

Each of 16 patients receiving a nasogastric tube had 50 mL of water followed by 100 mL of dietary formula (Osmolite HN, Abbott Laboratories, Columbus, OH) infused into the stomach. After mixing, gastric content was aspirated for the first Brix value (BV) measurement by refractometry. Then, 50 mL of water was infused into the stomach and a second BV was measured. The procedure of infusion of dietary formula (100 mL) and then water (50 mL) was repeated and followed by subsequent BV measurement. The same procedure was performed in an in vitro experiment. Formula concentration, GRV, and formula volume were calculated from the derived mathematical equations.

RESULTS

The formula concentrations, GRVs, and formula volumes calculated by using refractometry and the mathematical equations were close to the true values obtained from both in vivo and in vitro validation experiments.

CONCLUSIONS

Using this method, measurement of the BV of gastric contents is simple, reproducible, and inexpensive. Refractometry and the derived mathematical equations may be used to measure formula concentration, GRV, and formula volume, and also to serve as a tool for monitoring the gastric contents of patients receiving nasogastric feeding.

Nasoenteric Tube Complications

The use of nasoenteric tubes (NETs) is ubiquitous, and clinicians often take their placement, function, and maintenance for granted. NETs are used for gastrointestinal decompression, enteral feeding, medication administration, naso-biliary drainage, and specialized indications such as upper gastrointestinal bleeding. Morbidity associated with NETETs is common, but frequently subtle, mandating high index of suspicion, clinical vigilance, and patient safety protocols. Common complications include sinusitis, sore throat and epistaxis. More serious complications include luminal perforation, pulmonary injury, aspiration, and intracranial placement. Frequent monitoring and continual re-review of the indications for continued use of any NETET is prudent, including consideration of changing goals of care. This manuscript reviews NET-related complications and associated topics.

Effect of Presence/Absence of a Nasogastric Tube in the Same Person on Incidence of Aspiration

Objective. To determine what effect, if any, the presence or absence of a nasogastric (NG) tube in the same person had on the incidence of anterograde aspiration.

Design. Case series with planned data collection.

Setting. Large, urban, tertiary care teaching hospital.

Subjects and Methods. Referred sample of 62 consecutively enrolled adult inpatients for fiber-optic endoscopic evaluation of swallowing (FEES). Group 1 (n = 21) had either small-bore (n = 13) or large-bore (n = 8) NG tubes already in place and had a FEES first with the NG tube in place and a second FEES after NG tube removal. Group 2 (n = 41) did not have an NG tube and had a FEES first without an NG tube and a second FEES after placement of a small-bore NG tube. Time between FEES was approximately 5 minutes. Patients were tested with thin liquid and puree food consistencies. Occurrence of aspiration for each consistency dependent on the presence or absence of an NG tube was recorded.

Results. There were no significant differences ( P > .05) in aspiration status for both liquid and puree consistencies in the same person dependent on presence or absence of either a small-bore or large-bore NG tube.

Conclusions. Since objective swallowing evaluation (eg, FEES) can be performed with an NG tube in place, it is not necessary to remove an NG tube to evaluate for aspiration. Similarly, there is no contraindication to leaving an NG tube in place to supplement oral alimentation until nutritional requirements are achieved.

Effect of orogastric tubes on aspiration status and recommendations for oral feeding

OBJECTIVE

To investigate the effects, if any, of the presence of an orogastric tube on incidence of aspiration and oral diet recommendations.

STUDY DESIGN

Case series with planned data collection.

SETTING

Large, urban, tertiary care teaching hospital.

SUBJECTS AND METHODS

Referred sample of 10 consecutively enrolled inpatients (2 pediatric, aged 17 days and 3 months, respectively; and 8 adults, mean age 63 years). An orogastric tube was present for the first videofluoroscopic swallowing study or fiberoptic endoscopic evaluation of swallowing and then removed for the second swallow study.

RESULTS

There were no significant differences (P = 1.0) for both overall incidence of aspiration and aspiration by food consistency (liquid or puree) dependent on orogastric tube presence. All 9 participants recommended for an oral diet ate successfully.

CONCLUSIONS

An orogastric tube did not affect incidence of aspiration. A videofluoroscopic or endoscopic evaluation of swallowing can be performed with an orogastric tube present, and there is no contraindication to keeping an orogastric tube in place to supplement oral alimentation until prandial nutrition is adequate.

Fiberoptic endoscopic evaluation of swallowing in intensive care unit patients

Aspiration in critically ill patients frequently causes severe co-morbidity. We evaluated a diagnostic protocol using routine FEES in critically ill patients at risk to develop aspiration following extubation. We instructed intensive care unit physicians on specific risk factors for and clinical signs of aspiration following extubation in critically ill patients and offered bedside FEES for such patients. Over a 45-month period, we were called to perform 913 endoscopic examinations in 553 patients. Silent aspiration or aspiration with acute symptoms (cough or gag reflex as the bolus passed into the trachea) was detected in 69.3% of all patients. Prolonged non-oral feeding via a naso-gastric tube was initiated in 49.7% of all patients. In 13.2% of patients, a percutaneous endoscopic gastrostomy was initiated as a result of FEES findings, and in 6.3% an additional tracheotomy to prevent aspiration had to be initiated. In 59 out of 258 patients (22.9%), tracheotomies were closed, and 30.7% of all 553 patients could be managed with the immediate onset of an oral diet and compensatory treatment procedures. Additional radiological examinations were not required. FEES in critically ill patients allows for a rapid evaluation of deglutition and for the immediate initiation of symptom-related rehabilitation or for an early resumption of oral feeding.

The nasogastric feeding tube as a risk factor for aspiration and aspiration pneumonia

PURPOSE OF REVIEW

Aspiration is one of the most common complications in enterally fed patients. The source of aspiration is due to the accumulation of secretions in the pharynx of reflux gastric contents from the stomach into the pharynx. The true prevalence of aspiration is difficult to determine because of vague definitions, poor assessment methods, and varying levels of clinical recognition.

RECENT FINDINGS

There is evidence in the literature showing that the presence of a nasogastric feeding tube is associated with colonization and aspiration of pharyngeal secretions and gastric contents leading to a high incidence of Gram-negative pneumonia in patients on enteral nutrition. However, other aspects may be equally important and should also be considered when evaluating a patient suspected of having aspiration and aspiration pneumonia. The mechanisms responsible for aspiration in patients bearing a nasogastric feeding tube are (1). loss of anatomical integrity of the upper and lower esophageal sphincters, (2). increase in the frequency of transient lower esophageal sphincter relaxations, and (3). desensitization of the pharyngoglottal adduction reflex.

SUMMARY

Sometimes it is possible to differentiate whether the aspirate is gastric or pharyngeal. The kind of bacterial contamination is, however, more difficult to establish. Oral or dental disease, antibiotic therapy, systemic illness or malnutrition and reduction of salivary flow are responsible for colonization of Gram-negative bacteria in oral and pharyngeal flora in nasogastric-tube-fed patients. The use of a nasogastric feeding tube and the administration of food increase gastric pH and lead to colonization of gastric secretions. It has also been suggested that gastric bacteria could migrate upward along the tube and colonize the pharynx.