Ventilated patients may not need residual gastric volume monitoring

Among critically ill adults requiring mechanical ventilation and receiving early enteral nutrition, it may not be necessary to routinely monitor residual gastric volume as a means of averting vomiting and thus preventing aspiration and the development of ventilator-associated pneumonia, according to a report in the Jan. 16 issue of JAMA.

In a multicenter randomized trial involving 449 such patients, forgoing routine monitoring of residual gastric volume was found "noninferior" at preventing ventilator-associated pneumonia to the standard practice of performing this monitoring every 6 hours. Moreover, patients who were not monitored actually were more likely to achieve their nutritional targets, while showing equivalent mortality, infection rates, lengths of hospital stay, lengths of ICU stay, and organ failure scores, said Dr. Jean Reignier of Centre Hospitalier Departemental de la Vendee, La Roche-sur Yon (France), and his associates.

"Residual gastric volume monitoring leads to unnecessary interruption of enteral nutrition delivery with subsequent inadequate feeding, and should be removed from the standard care of critically ill patients receiving invasive mechanical ventilation and early enteral nutrition," the investigators said.

It is thought that higher gastric volume causes intolerance of enteral feeding, with its attendant gastroesophageal reflux and vomiting. Monitoring of residual gastric volume involves periodically aspirating the stomach through the nasogastric tube with a 50-mL syringe. If the volume exceeds a cutoff – usually 250 mL – enteral nutrition is stopped or decreased to minimize the risk of vomiting, aspiration, and subsequent development of ventilator-associated pneumonia.

However, it has never been definitively established that increased gastric volume does lead to vomiting (or exactly what the cutoff amount should be), that this vomiting does lead to ventilator-associated pneumonia, or that the monitoring procedure actually reduces the risk of pneumonia. And monitoring has been linked to decreased calorie delivery and its associated morbidity.

Dr. Reignier and his colleagues found in a preliminary study at a single ICU that forgoing the monitoring procedure did not raise the rate of ventilator-associated pneumonia. They then performed this noninferiority study to test the theory that residual gastric volume monitoring may not be necessary for this purpose.

Adult patients who were expected to require more than 48 hours of mechanical ventilation at nine ICUs were enrolled over a 1-year period. Three of the ICUs were medical and six were medical-surgical. Three were in university hospitals and six were in general hospitals affiliated with a university.

The study subjects were randomly assigned to receive either standard care, which included monitoring of residual gastric volume every 6 hours or the "intervention" of no monitoring.

The primary outcome was the rate of ventilator-associated pneumonia. In the intention-to-treat analysis, this rate was 15.8% in the control group (222 patients) and 16.7% in the "intervention" group (227 patients), a nonsignificant difference. In the per-protocol analysis, this rate was 16.3% in the control group (215 patients) and 17.8% in the intervention group (208 patients), also a nonsignificant difference.

Thus, forgoing routine monitoring of residual gastric volume was noninferior to performing such monitoring at preventing this form of pneumonia, the researchers said (JAMA 2013;309:249-56).

In further analyses, the cumulative incidences of ventilator-associated pneumonia also were not significantly different between the two study groups. Microbiologic testing showed that the organisms causing pneumonia were the same between the two groups, as were the proportions of infections caused by Staphylococcus aureus, Streptococcus species, Enterobacteriaceae, and Pseudomonadaceae.

The two study groups also did not differ in short- or long-term mortality; rates of other ICU-acquired infections; scores on measures of organ failure; or the duration of ventilation, ICU stay, or hospital stay.

It was interesting that the proportion of patients who vomited was significantly higher in the unmonitored than in the monitored group, and that the number of vomiting episodes also was significantly higher in the unmonitored group, yet the rate of pneumonia was not significantly different, Dr. Reignier and his associates noted.

Despite higher rates of vomiting, more patients in the unmonitored group achieved their calorie targets on enteral nutrition.

The investigators proposed several explanations for their findings.

In several previous studies, residual gastric volumes did not correlate with vomiting or aspiration rates. Volumes lower than 250 mL did not correlate with decreased complications, and values as high as 500 mL did not correlate with increased rates of pneumonia.

Second, the measurement of residual gastric volume has never been standardized or validated. And the accuracy of gastric aspiration through the nasogastric tube may vary according to tube position, tube diameter, the number of tube openings in the stomach, the level of aspiration in the stomach, and the clinician’s experience, the investigators said.

Third, and perhaps most important, many studies have challenged the role of gastric aspiration in the development of ventilator-associated pneumonia. The oral cavity, not the stomach, may be the significant reservoir of pathogens that cause this form of pneumonia, they said.

Eliminating the routine monitoring of residual gastric volume would be advantageous in that it would significantly reduce the workload of nurses and other clinicians, allowing them to focus on other interventions that have proved their value, Dr. Reignier and his colleagues added.

The study was sponsored by Centre Hospitalier Departmental de la Vendee. No financial conflicts of interest were reported.

Among critically ill adults requiring mechanical ventilation and receiving early enteral nutrition, it may not be necessary to routinely monitor residual gastric volume as a means of averting vomiting and thus preventing aspiration and the development of ventilator-associated pneumonia, according to a report in the Jan. 16 issue of JAMA.

In a multicenter randomized trial involving 449 such patients, forgoing routine monitoring of residual gastric volume was found "noninferior" at preventing ventilator-associated pneumonia to the standard practice of performing this monitoring every 6 hours. Moreover, patients who were not monitored actually were more likely to achieve their nutritional targets, while showing equivalent mortality, infection rates, lengths of hospital stay, lengths of ICU stay, and organ failure scores, said Dr. Jean Reignier of Centre Hospitalier Departemental de la Vendee, La Roche-sur Yon (France), and his associates.

"Residual gastric volume monitoring leads to unnecessary interruption of enteral nutrition delivery with subsequent inadequate feeding, and should be removed from the standard care of critically ill patients receiving invasive mechanical ventilation and early enteral nutrition," the investigators said.

It is thought that higher gastric volume causes intolerance of enteral feeding, with its attendant gastroesophageal reflux and vomiting. Monitoring of residual gastric volume involves periodically aspirating the stomach through the nasogastric tube with a 50-mL syringe. If the volume exceeds a cutoff – usually 250 mL – enteral nutrition is stopped or decreased to minimize the risk of vomiting, aspiration, and subsequent development of ventilator-associated pneumonia.

However, it has never been definitively established that increased gastric volume does lead to vomiting (or exactly what the cutoff amount should be), that this vomiting does lead to ventilator-associated pneumonia, or that the monitoring procedure actually reduces the risk of pneumonia. And monitoring has been linked to decreased calorie delivery and its associated morbidity.

Dr. Reignier and his colleagues found in a preliminary study at a single ICU that forgoing the monitoring procedure did not raise the rate of ventilator-associated pneumonia. They then performed this noninferiority study to test the theory that residual gastric volume monitoring may not be necessary for this purpose.

Adult patients who were expected to require more than 48 hours of mechanical ventilation at nine ICUs were enrolled over a 1-year period. Three of the ICUs were medical and six were medical-surgical. Three were in university hospitals and six were in general hospitals affiliated with a university.

The study subjects were randomly assigned to receive either standard care, which included monitoring of residual gastric volume every 6 hours or the "intervention" of no monitoring.

The primary outcome was the rate of ventilator-associated pneumonia. In the intention-to-treat analysis, this rate was 15.8% in the control group (222 patients) and 16.7% in the "intervention" group (227 patients), a nonsignificant difference. In the per-protocol analysis, this rate was 16.3% in the control group (215 patients) and 17.8% in the intervention group (208 patients), also a nonsignificant difference.

Thus, forgoing routine monitoring of residual gastric volume was noninferior to performing such monitoring at preventing this form of pneumonia, the researchers said (JAMA 2013;309:249-56).

In further analyses, the cumulative incidences of ventilator-associated pneumonia also were not significantly different between the two study groups. Microbiologic testing showed that the organisms causing pneumonia were the same between the two groups, as were the proportions of infections caused by Staphylococcus aureus, Streptococcus species, Enterobacteriaceae, and Pseudomonadaceae.

The two study groups also did not differ in short- or long-term mortality; rates of other ICU-acquired infections; scores on measures of organ failure; or the duration of ventilation, ICU stay, or hospital stay.

It was interesting that the proportion of patients who vomited was significantly higher in the unmonitored than in the monitored group, and that the number of vomiting episodes also was significantly higher in the unmonitored group, yet the rate of pneumonia was not significantly different, Dr. Reignier and his associates noted.

Despite higher rates of vomiting, more patients in the unmonitored group achieved their calorie targets on enteral nutrition.

The investigators proposed several explanations for their findings.

In several previous studies, residual gastric volumes did not correlate with vomiting or aspiration rates. Volumes lower than 250 mL did not correlate with decreased complications, and values as high as 500 mL did not correlate with increased rates of pneumonia.

Second, the measurement of residual gastric volume has never been standardized or validated. And the accuracy of gastric aspiration through the nasogastric tube may vary according to tube position, tube diameter, the number of tube openings in the stomach, the level of aspiration in the stomach, and the clinician’s experience, the investigators said.

Third, and perhaps most important, many studies have challenged the role of gastric aspiration in the development of ventilator-associated pneumonia. The oral cavity, not the stomach, may be the significant reservoir of pathogens that cause this form of pneumonia, they said.

Eliminating the routine monitoring of residual gastric volume would be advantageous in that it would significantly reduce the workload of nurses and other clinicians, allowing them to focus on other interventions that have proved their value, Dr. Reignier and his colleagues added.

The study was sponsored by Centre Hospitalier Departmental de la Vendee. No financial conflicts of interest were reported.

Among critically ill adults requiring mechanical ventilation and receiving early enteral nutrition, it may not be necessary to routinely monitor residual gastric volume as a means of averting vomiting and thus preventing aspiration and the development of ventilator-associated pneumonia, according to a report in the Jan. 16 issue of JAMA.

In a multicenter randomized trial involving 449 such patients, forgoing routine monitoring of residual gastric volume was found "noninferior" at preventing ventilator-associated pneumonia to the standard practice of performing this monitoring every 6 hours. Moreover, patients who were not monitored actually were more likely to achieve their nutritional targets, while showing equivalent mortality, infection rates, lengths of hospital stay, lengths of ICU stay, and organ failure scores, said Dr. Jean Reignier of Centre Hospitalier Departemental de la Vendee, La Roche-sur Yon (France), and his associates.

"Residual gastric volume monitoring leads to unnecessary interruption of enteral nutrition delivery with subsequent inadequate feeding, and should be removed from the standard care of critically ill patients receiving invasive mechanical ventilation and early enteral nutrition," the investigators said.

It is thought that higher gastric volume causes intolerance of enteral feeding, with its attendant gastroesophageal reflux and vomiting. Monitoring of residual gastric volume involves periodically aspirating the stomach through the nasogastric tube with a 50-mL syringe. If the volume exceeds a cutoff – usually 250 mL – enteral nutrition is stopped or decreased to minimize the risk of vomiting, aspiration, and subsequent development of ventilator-associated pneumonia.

However, it has never been definitively established that increased gastric volume does lead to vomiting (or exactly what the cutoff amount should be), that this vomiting does lead to ventilator-associated pneumonia, or that the monitoring procedure actually reduces the risk of pneumonia. And monitoring has been linked to decreased calorie delivery and its associated morbidity.

Dr. Reignier and his colleagues found in a preliminary study at a single ICU that forgoing the monitoring procedure did not raise the rate of ventilator-associated pneumonia. They then performed this noninferiority study to test the theory that residual gastric volume monitoring may not be necessary for this purpose.

Adult patients who were expected to require more than 48 hours of mechanical ventilation at nine ICUs were enrolled over a 1-year period. Three of the ICUs were medical and six were medical-surgical. Three were in university hospitals and six were in general hospitals affiliated with a university.

The study subjects were randomly assigned to receive either standard care, which included monitoring of residual gastric volume every 6 hours or the "intervention" of no monitoring.

The primary outcome was the rate of ventilator-associated pneumonia. In the intention-to-treat analysis, this rate was 15.8% in the control group (222 patients) and 16.7% in the "intervention" group (227 patients), a nonsignificant difference. In the per-protocol analysis, this rate was 16.3% in the control group (215 patients) and 17.8% in the intervention group (208 patients), also a nonsignificant difference.

Thus, forgoing routine monitoring of residual gastric volume was noninferior to performing such monitoring at preventing this form of pneumonia, the researchers said (JAMA 2013;309:249-56).

In further analyses, the cumulative incidences of ventilator-associated pneumonia also were not significantly different between the two study groups. Microbiologic testing showed that the organisms causing pneumonia were the same between the two groups, as were the proportions of infections caused by Staphylococcus aureus, Streptococcus species, Enterobacteriaceae, and Pseudomonadaceae.

The two study groups also did not differ in short- or long-term mortality; rates of other ICU-acquired infections; scores on measures of organ failure; or the duration of ventilation, ICU stay, or hospital stay.

It was interesting that the proportion of patients who vomited was significantly higher in the unmonitored than in the monitored group, and that the number of vomiting episodes also was significantly higher in the unmonitored group, yet the rate of pneumonia was not significantly different, Dr. Reignier and his associates noted.

Despite higher rates of vomiting, more patients in the unmonitored group achieved their calorie targets on enteral nutrition.

The investigators proposed several explanations for their findings.

In several previous studies, residual gastric volumes did not correlate with vomiting or aspiration rates. Volumes lower than 250 mL did not correlate with decreased complications, and values as high as 500 mL did not correlate with increased rates of pneumonia.

Second, the measurement of residual gastric volume has never been standardized or validated. And the accuracy of gastric aspiration through the nasogastric tube may vary according to tube position, tube diameter, the number of tube openings in the stomach, the level of aspiration in the stomach, and the clinician’s experience, the investigators said.

Third, and perhaps most important, many studies have challenged the role of gastric aspiration in the development of ventilator-associated pneumonia. The oral cavity, not the stomach, may be the significant reservoir of pathogens that cause this form of pneumonia, they said.

Eliminating the routine monitoring of residual gastric volume would be advantageous in that it would significantly reduce the workload of nurses and other clinicians, allowing them to focus on other interventions that have proved their value, Dr. Reignier and his colleagues added.

The study was sponsored by Centre Hospitalier Departmental de la Vendee. No financial conflicts of interest were reported.