Table 2 Studies about the effect of opioids on lower GI dysmotility in the ICU

Mostafa et al. [11]

POS

48 patients in the mixed medical and surgical ICU

Not constipated (n = 8) vs constipated (n = 40)

Constipation and its implications in the ICU

Delayed weaning from mechanical ventilation and enteral feeding

Alfentanil

Opioids had little effect on constipation

Van et al. [43]

Descriptive cohort study

44 individuals in mixed surgical and medical ICU

SDD (n = 22) vs control (n = 22)

To describe the influence of severity of illness, medication and selective decontamination on defecation

Severity of illness, vasoactive medication, morphine, duration of mechanical ventilation and length of ICU stay influenced the time to first defecate

Morphine

Morphine administration at least 4 days may be associated with delayed defecation

Nassar et al. [45]

POS

106 patients in the surgical ICU

Not constipated (n = 33) vs constipated (n = 73)

To determine the risk factors of constipation and its implications

Early enteral nutrition was associated with less constipation. Constipation was not associated with higher ICU mortality, length of stay and days free from mechanical ventilation

Fentanyl

Opioids were not associated with an increased incidence of constipation

Gacouin et al. [46]

POS

609 patients with mechanical ventilation at least 6 days

Late defecation (defecation ≥ 6 days after admission to ICU) group (n = 353) vs early defecation group (n = 256)

To determine the risk factors of late defecation and its implications

PaO₂/FIO₂ ratio of < 150 mm Hg and systolic blood pressure of < 90 mm Hg during the first 5 days of mechanical ventilation were independently associated with delayed defecation

Morphine

Unadjusted univariate analysis suggested that the use of opiates had an impact on the late defecation

Deane et al. [42]

POS

44 individuals mixed medical and surgical

Critically ill patients (n = 28) vs healthy volunteers (n = 16)

To determine small intestinal glucose absorption and small intestinal transit in critically ill patients

Critical illness was associated with reduced small intestinal glucose absorption

Not reported

Small transit were delayed in critical illness

Fukuda et al. 2016[47]

RS

282 patients who stayed in the ICU at least 7 days

Late defecation (defecation ≥ 6 days after admission to ICU) group (n = 96) vs early defecation group (n = 186)

To investigate the risk factors for late defecation and its association with the outcomes of ICU patients

Late enteral nutrition, sedatives and surgery were risk factors for late defecation, and late defecation was associated with a prolonged ICU stay

Fentanyl

Fentanyl was not a risk factor for late defecation

Prat et al. [48]

POS

189 patients

Not constipated (n = 91) vs all constipated (n = 98)

To determine the frequency and significance of constipation according to its definition criterion

Without laxation at least 6 days was more associated with specific outcomes

Sufentanyl

Opioids were associated with patients who constipated more than 6 days

Launey et al. [44]

POS

396 adults with at least 2 days’ invasive ventilation

NA

To determine the factors associated with the time to defecation

Non-invasive ventilation and the duration of ventilation were associated with the time to defecation

Morphine equivalents

Opioids were not associated with the time to defecation

Nguyen et al. [84]

POS

248 Mechanically ventilated patients receiving enteral nutrition

Patients with IGT (n = 50) vs patients without IGT (n = 198)

To determine the proportion and risk factors of critically ill adults with IGT

Pragmatically defined IGT was common in critical illness and associated with significant morbidity

Not reported

Use of opioids was identified as a risk factor for IGT