Intravenous acetaminophen had no effect on decreasing the behavioral pain scale (BPS) and need of morphine sulfate in intubated patients admitted to ICU.

Presence of endotracheal tube (ETT) can induce a significant pain, even in a patient not completely conscious. There are many ways to estimate the amount of pain in such patients who cannot communicate verbally with their caregivers. Most of these tools are simple and offer a rapid way to measure and monitor the amount of pain in these patients during hospitalization. There are enormous pharmacological and nonpharmacological ways to manage pain. Morphine sulfate is the most popular medication of pain management in patients hospitalized to the Intensive Care Units (ICUs). Unfortunately, its use is accompanied with some complications such as central nervous system and respiratory suppression, nausea/vomiting, histamine release, and consequent fall in blood pressure (BP) level. Acetaminophen is an antipyretic and analgesic agent, and it is more commonly used to relieve mild to moderate pain caused by different etiologies. Considering the fact that in patients in need of critical care, intravenous (IV) acetaminophen has less complications while being injected and afterward compared to IV morphine sulfate, current study tries to evaluate the effect of acetaminophen on reducing the need for morphine sulfate in intubated patients admitted to ICU.

Rationale behind research:

Although, there are many studies which have showed the effectiveness of acetaminophen on decreasing the need to IV narcotics in pain management, no study had targeted intubated patients in ICU setting and the present study tried to evaluate the same.

Objective:

To evaluate the effect of intravenous (IV) acetaminophen on reducing the need for morphine sulfate in incubated patients admitted to the Intensive Care Unit (ICU).

Study outcomes:

• Total dose of morphine sulfate needed and its complications
• The mean pain score or the BPS score

Time Points: After every 6 hours between 4 days 

Outcomes:

• The mean pain score: The mean pain score was 7.36 (95% CI, 6.83–7.91) on the 1st day and 4.33, 3.93, and 3.66 on day 2,3 and 4 respectively. The mean pain score was significantly lower on 2nd and 4th days, in which the patients had received morphine sulfate (4.0; 95% CI, 3.7–4.36) compared to 1st and 3rd days in which the patients had received acetaminophen in addition to morphine sulfate too (5.65; 95% CI, 5.31–6.05) (P < 0.001).

Figure 1: Comparison between pain scores of patients after acetaminophen prescription and withdrawal

• Use of morphine sulphate: Cumulative dose of morphine sulfate used in the 1st day was 8.92 mg, while it was 6.47 mg, 3.15 mg, and 3.22 mg on day 2, 3 and 4 respectively. Altogether, in the 1st and 3rd days, the patients received 12.07 mg compared to 9.7 mg in the 2nd and 4th days. Statistical analysis showed significantly higher morphine sulfate in the days that patients had received acetaminophen compared to the days they had received placebo.

Figure 2: Comparison between the daily dose of morphine sulfate prescribed

The results from the present study showed that IV acetaminophen had no role in decreasing the need of intubated patients to IV morphine to manage pain in US. All of the studies previously done evaluated the positive effect of IV acetaminophen on the decrease of opiates use and its complications in a selected group of patients needing surgical interventions. Acetaminophen was prescribed prior to or during the intervention; none of them was designed for intubated patients in intensive care setting. Hence, it seems that it is the first prospective double-blind controlled trial done.

Kelly et al. studied 100 patients in need of knee surgery, retrospectively. They found that the case group (patients who received IV acetaminophen perioperatively) had no statistically significant difference with the control group in the rate of opiates used after surgery (P = 0.987). In another placebo-controlled double-blinded randomized trial, Cattabriga et al. prescribed IV acetaminophen for 72 h to 56 patients after cardiac surgery, whereas 57 counterparts received no acetaminophen; there was no statistically significant difference between the two groups from the point of cumulative morphine used (P = 0.273). There are lots of studies which have shown that using IV acetaminophen as a multimodal analgesia has had a narcotic saving effect; it has reduced cumulative doses of morphine sulfate or other opioids needed to control pain on different clinical settings.