Insulin resistance may predict ventilator-associated pneumonia

LAS VEGAS – The development of euglycemic insulin resistance soon after intubation may herald the onset of ventilator-associated pneumonia, a study by investigators at Vanderbilt University in Nashville, Tenn., has shown.

Researchers compared 92 critically injured trauma patients who developed VAP (ventilator-associated pneumonia) 3-4 days after intubation with 2,162 who did not. All the subjects had their blood glucose levels kept mostly between 80 and 150 mg/dL with the help of a computer-assisted protocol that adjusted insulin drip rates as necessary, lead investigator Dr. Kaushik Mukherjee reported at the annual meeting of the Surgical Infection Society.

There were no differences in baseline demographics between the two groups, but compared with controls, patients who developed VAP needed significantly higher insulin drip rates to stay in that range the day before and the first and third days after they met clinical criteria for VAP diagnosis (maximum difference, 1.1 U/hr [95% CI, 0.8-1.5; P less than .001]).

The M multiplier, a surrogate for insulin resistance calculated from blood glucose levels and insulin drip rates, was significantly higher 2 days before VAP was diagnosed, and remained so for 10 days afterward.

If the findings hold up with further investigation, the Vanderbilt team believes they may one day help predict who’s at risk for VAP so that preventative measures can be taken. Among other things, the model will need to incorporate body mass index, steroid use, tube-feeding schedule, and other confounders that impact insulin requirements, and be put through a prospective trial.

Even so, "these data indicate euglycemic insulin resistance may be an important new indicator for VAP in the era of strict glycemic control. [This] may be valuable moving forward," said Dr. Mukherjee of Vanderbilt’s division of trauma and surgical critical care.

"We believe that critically injured patients with VAP show euglycemic insulin resistance as measured by the multiplier, and we think [that] could be predictive of infection. We are hoping to turn this into an insulin resistance–based screening tool for VAP that would help us decide when we should obtain a [bronchoalveolar lavage]. Earlier detection of pneumonias could result in earlier antibiotic therapy and survival," he said.

Patients in the study were at least 16 years old, and had been ventilated for at least 48 hours.

Both VAP and control patients needed increasing amounts of insulin in the 10 days following intubation, probably "due to added nutrition, but [the VAP group required] a more rapid increase in their insulin infusion rates" starting about 3 days before VAP was diagnosed.

Overall, VAP patients had lower blood glucose levels both before and after diagnosis and were less likely to exceed the target range. "We think it’s because their innate ability to control glucose [was more] impaired, [so] there was less variability from the patient’s own system," Dr. Mukherjee said.

He said he had no relevant financial disclosures.

[email protected]

LAS VEGAS – The development of euglycemic insulin resistance soon after intubation may herald the onset of ventilator-associated pneumonia, a study by investigators at Vanderbilt University in Nashville, Tenn., has shown.

Researchers compared 92 critically injured trauma patients who developed VAP (ventilator-associated pneumonia) 3-4 days after intubation with 2,162 who did not. All the subjects had their blood glucose levels kept mostly between 80 and 150 mg/dL with the help of a computer-assisted protocol that adjusted insulin drip rates as necessary, lead investigator Dr. Kaushik Mukherjee reported at the annual meeting of the Surgical Infection Society.

There were no differences in baseline demographics between the two groups, but compared with controls, patients who developed VAP needed significantly higher insulin drip rates to stay in that range the day before and the first and third days after they met clinical criteria for VAP diagnosis (maximum difference, 1.1 U/hr [95% CI, 0.8-1.5; P less than .001]).

The M multiplier, a surrogate for insulin resistance calculated from blood glucose levels and insulin drip rates, was significantly higher 2 days before VAP was diagnosed, and remained so for 10 days afterward.

If the findings hold up with further investigation, the Vanderbilt team believes they may one day help predict who’s at risk for VAP so that preventative measures can be taken. Among other things, the model will need to incorporate body mass index, steroid use, tube-feeding schedule, and other confounders that impact insulin requirements, and be put through a prospective trial.

Even so, "these data indicate euglycemic insulin resistance may be an important new indicator for VAP in the era of strict glycemic control. [This] may be valuable moving forward," said Dr. Mukherjee of Vanderbilt’s division of trauma and surgical critical care.

"We believe that critically injured patients with VAP show euglycemic insulin resistance as measured by the multiplier, and we think [that] could be predictive of infection. We are hoping to turn this into an insulin resistance–based screening tool for VAP that would help us decide when we should obtain a [bronchoalveolar lavage]. Earlier detection of pneumonias could result in earlier antibiotic therapy and survival," he said.

Patients in the study were at least 16 years old, and had been ventilated for at least 48 hours.

Both VAP and control patients needed increasing amounts of insulin in the 10 days following intubation, probably "due to added nutrition, but [the VAP group required] a more rapid increase in their insulin infusion rates" starting about 3 days before VAP was diagnosed.

Overall, VAP patients had lower blood glucose levels both before and after diagnosis and were less likely to exceed the target range. "We think it’s because their innate ability to control glucose [was more] impaired, [so] there was less variability from the patient’s own system," Dr. Mukherjee said.

He said he had no relevant financial disclosures.

[email protected]

LAS VEGAS – The development of euglycemic insulin resistance soon after intubation may herald the onset of ventilator-associated pneumonia, a study by investigators at Vanderbilt University in Nashville, Tenn., has shown.

Researchers compared 92 critically injured trauma patients who developed VAP (ventilator-associated pneumonia) 3-4 days after intubation with 2,162 who did not. All the subjects had their blood glucose levels kept mostly between 80 and 150 mg/dL with the help of a computer-assisted protocol that adjusted insulin drip rates as necessary, lead investigator Dr. Kaushik Mukherjee reported at the annual meeting of the Surgical Infection Society.

There were no differences in baseline demographics between the two groups, but compared with controls, patients who developed VAP needed significantly higher insulin drip rates to stay in that range the day before and the first and third days after they met clinical criteria for VAP diagnosis (maximum difference, 1.1 U/hr [95% CI, 0.8-1.5; P less than .001]).

The M multiplier, a surrogate for insulin resistance calculated from blood glucose levels and insulin drip rates, was significantly higher 2 days before VAP was diagnosed, and remained so for 10 days afterward.

If the findings hold up with further investigation, the Vanderbilt team believes they may one day help predict who’s at risk for VAP so that preventative measures can be taken. Among other things, the model will need to incorporate body mass index, steroid use, tube-feeding schedule, and other confounders that impact insulin requirements, and be put through a prospective trial.

Even so, "these data indicate euglycemic insulin resistance may be an important new indicator for VAP in the era of strict glycemic control. [This] may be valuable moving forward," said Dr. Mukherjee of Vanderbilt’s division of trauma and surgical critical care.

"We believe that critically injured patients with VAP show euglycemic insulin resistance as measured by the multiplier, and we think [that] could be predictive of infection. We are hoping to turn this into an insulin resistance–based screening tool for VAP that would help us decide when we should obtain a [bronchoalveolar lavage]. Earlier detection of pneumonias could result in earlier antibiotic therapy and survival," he said.

Patients in the study were at least 16 years old, and had been ventilated for at least 48 hours.

Both VAP and control patients needed increasing amounts of insulin in the 10 days following intubation, probably "due to added nutrition, but [the VAP group required] a more rapid increase in their insulin infusion rates" starting about 3 days before VAP was diagnosed.

Overall, VAP patients had lower blood glucose levels both before and after diagnosis and were less likely to exceed the target range. "We think it’s because their innate ability to control glucose [was more] impaired, [so] there was less variability from the patient’s own system," Dr. Mukherjee said.

He said he had no relevant financial disclosures.

[email protected]