[Acetaminophene-induced hypotension in intensive care unit: a prospective study]

A narrative review of paracetamol-induced hypotension: Keeping the patient safe

Aim

To understand the prevalence and epidemiology of paracetamol‐induced hypotension and clinical implications for contemporaneous practice.

Design

Narrative review.

Methods

In May and June 2020, an open‐date literature search of English publications indexed in ProQuest, PubMed, and EBSCO was conducted with the search terms ‘acetaminophen’ and ‘hypotension’ and related search combinations (‘paracetamol’, ‘propacetamol’, ‘low blood pressure’, ‘fever’, ‘sepsis’, and ‘shock’) to identify peer‐reviewed publications of blood pressure changes after paracetamol administration in humans.

Results

A pattern of blood pressure reduction following the administration of paracetamol is demonstrated in the 27 studies included in this review. Haemodynamic intervention often followed persistent blood pressure reduction, and was greatest in febrile critically ill patients who received parenteral paracetamol.

Effect of Intravenous Acetaminophen on Mean Arterial Blood Pressure: A Post Hoc Analysis of the EFfect of Intravenous ACetaminophen on PosToperative HypOxemia After Abdominal SurgeRy Trial

BACKGROUND

Acetaminophen is commonly used as part of multimodal analgesia for acute pain. The intravenous formulation offers a more predictable bioavailability compared to oral and rectal acetaminophen. There have been reports of hypotension with intravenous acetaminophen attributable to centrally mediated and vasodilatory effects. We tested the hypothesis that in adults having abdominal surgery the use of intravenous acetaminophen versus placebo for postoperative pain management is associated with a decrease in mean arterial pressure (MAP) after its administration.

METHODS

This is a substudy of eFfect of intravenous ACetaminophen on posToperative hypOxemia after abdominal surgeRy (FACTOR) trial (NCT02156154). FACTOR trial randomly assigned adults undergoing abdominal surgery to either 1 g of acetaminophen or placebo every 6 hours during the first postoperative 48 hours. Continuous monitoring of blood pressure was obtained by noninvasive ViSi Mobile device (Sotera Wireless, Inc, San Diego, CA) at 15-second intervals during initial 48 hours postoperatively. We excluded patients without continuous monitoring data available. The primary outcome was the MAP difference between MAP 5 minutes before study drug administration (baseline) and MAP 30 minutes poststudy drug administration initiation. We used a linear mixed effects model to assess the treatment effect on MAP change. The secondary outcome was MAP area under baseline (AUB) during the 30 minutes after treatment. In a sensitivity analysis of change in MAP from predrug to postdrug administration, we instead used postdrug MAP as the outcome adjusting for the baseline MAP in the model.

RESULTS

Among 358 patients analyzed, 182 received acetaminophen and 176 placebo. The mean (standard deviation [SD]) of average MAP change was -0.75 (5.9) mm Hg for the treatment and 0.32 (6.3) mm Hg for the placebo. Acetaminophen was found to decrease the MAP from baseline more than placebo after drug administration. The estimated difference in mean change of MAP was -1.03 (95% confidence interval [CI] -1.60 to -0.47) mm Hg; P < .001. The sensitivity analysis showed postoperative MAP in the acetaminophen group was 1.33 (95% CI, 0.76-1.90) mm Hg lower than in the placebo group (P < .001). The median of MAP AUB was 33 [Q1 = 3.3, Q3 = 109] mm Hg × minutes for the treatment and 23 [1.6, 79] mm Hg × minutes for the placebo. Acetaminophen was found to increase the AUB with an estimated median difference of 15 (95% CI, 5-25) mm Hg × minutes (P = .003).

CONCLUSIONS

Intravenous acetaminophen decreases MAP after its administration. However, this decrease does not appear to be clinically meaningful. Clinicians should not refrain to use intravenous acetaminophen for acute pain management because of worries of hypotension.

How to manage fever in brain-injured patients

Fever represents a frequent and dangerous secondary insult for the injured brain and is often associated with worsened neurological outcomes. The identification of fever in the Neuro-Intensive Care Unit requires careful monitoring and rapid and effective treatment. The main objective of this article was to provide practical information regarding temperature monitoring, triggers for intervention and fever management in brain injured patients.

Safety issues of current analgesics: an update

Pain represents a complex experience which can be approached by various medicines. Non-opioid and opioid analgesics are the most common drugs used to manage different types of pain. The increased attention nowadays to pain management entailed concomitantly more frequent adverse drug reactions (ADRs) related to analgesic use. Drug-drug interactions can be sometimes responsible for the adverse effects. However, a significant proportion of analgesic ADRs are preventable, which would avoid patient suffering. In order to draw the attention to analgesics risks and to minimize the negative consequences related to their use, the present review comprises a synthesis of the most important safety issues described in the scientific literature. It highlights the potential risks of the most frequently used analgesic medicines: non-opioid (paracetamol, metamizole, non-steroidal anti-inflammatory drugs) and opioid analgesics. Even if there is a wide experience in their use, they continue to capture attention with safety concerns and with potential risks recently revealed. Acknowledging potential safety problems represents the first step for health professionals in assuring a safe and efficient analgesic treatment with minimum risks to patients. Taking into consideration all medical and environmental factors and carefully monitoring the patients are also essential in preventing and early detecting analgesic ADRs.

Intravenous paracetamol for fever control in acute brain injury patients: cerebral and hemodynamic effects

BACKGROUND

Fever occurs frequently in acute brain injury patients, and its occurrence is associated with poorer outcomes. Paracetamol, an antipyretic frequently employed in patients with cerebral damage, may cause hypotension. We evaluated the cerebral and hemodynamic effects of intravenous (IV) paracetamol for the control of fever in Neuro-Intensive Care Unit (NICU) patients.

METHODS

This is a prospective observational study in which we enrolled 32 NICU patients: Subarachnoid Hemorrhage (SAH, n = 18), Traumatic Brain Injury (TBI, n = 10), Intracerebral Hemorrhage (ICH, n = 2) and Acute Ischemic Stroke (AIS, n = 2).

RESULTS

The administration of paracetamol resulted in a decrease of core body temperature (Tc) (p = 0,0001), mean arterial pressure (MAP) (p = 0,0006), cerebral perfusion pressure (CPP) (p = 0,0033), and jugular venous oxygen saturation (SjVO2) (p = 0.0193), and in an increase of arteriojugular venous differences of oxygen (AVDO2) (p = 0.0012). The proportion of patients who had an infusion of norepinephrine increased from 47 % to 75 % (p = 0.0039 McNemar Test). When intracranial pressure (ICP) at the start of paracetamol infusion (t-0) was compared with the measurement of ICP after 2 h, a significant correlation was observed (r = 0.669, p = 0.0002). This marked and significant correlation can be explained by the fact that for the higher levels of ICP assessed at t-0 (greater than 15 mmHg), we observed a marked reduction of ICP concomitant with the decrease of Tc. No problems related to norepinephrine administration and/or increase in dosage were observed.

CONCLUSION

Paracetamol administration is effective but exposes patients to hypotensive episodes that must be recognized and treated expeditiously to prevent further damage to the injured brain.

Decreasing severe pain and serious adverse events while moving intensive care unit patients: a prospective interventional study (the NURSE-DO project)

INTRODUCTION

A quality-improvement project was conducted to reduce severe pain and stress-related events while moving ICU-patients.

METHODS

The Plan-Do-Check-Adjust cycle was studied during four one-month phases, separated by five-month interphases. All consecutive patients staying more than 24 hours were evaluated every morning while being moved for nursing care (bathing, massage, sheet-change, repositioning). Phase 1 was considered as the baseline. Implemented and adjusted quality-interventions were assessed at phases 2 and 3, respectively. An independent post-intervention control-audit was performed at Phase 4. Primary-endpoints were the incidence of severe pain defined by a behavioral pain scale > 5 or a 0 to 10 visual numeric rating scale > 6, and the incidence of serious adverse events (SAE): cardiac arrest, arrhythmias, tachycardia, bradycardia, hypertension, hypotension, desaturation, bradypnea or ventilatory distress. Pain, SAE, patients' characteristics and analgesia were compared among the phases by a multivariate mixed-effects model for repeated-measurements, adjusted on severity index, age, admission type (medical/surgical), intubation and sedation status.

RESULTS

During the four studied phases, 630 care procedures were analyzed in 53, 47, 43 and 50 patients, respectively. Incidence of severe pain decreased significantly from 16% (baseline) to 6% in Phase 3 (odds ratio (OR) = 0.33 (0.11; 0.98), P = 0.04) and 2% in Phase 4 (OR = 0.30 (0.12; 0.95), P = 0.02). Incidence of SAE decreased significantly from 37% (baseline) to 17% in Phase 3 and 21% in Phase 4. In multivariate analysis, SAE were independently associated with Phase 3 (OR = 0.40 (0.23; 0.72), P < 0.01), Phase 4 (OR = 0.53 (0.30; 0.92), P = 0.03), intubation status (OR = 1.91 (1.28; 2.85), P < 0.01) and severe pain (OR = 2.74 (1.54; 4.89), P < 0.001).

CONCLUSIONS

Severe pain and serious adverse events are common and strongly associated while moving ICU patients for nursing procedures. Quality improvement of pain management is associated with a decrease of serious adverse events. Careful documentation of pain management during mobilization for nursing procedures could be implemented as a health quality indicator in the ICU.

Effects of high-dose paracetamol on blood pressure in acute stroke

BACKGROUND

Early administration of paracetamol may improve outcome of patients with acute stroke and a baseline body temperature of 37°C or above by lowering body temperature and preventing fever. Besides its antipyretic effects, paracetamol may affect blood pressure through cyclooxygenase-2 inhibition. We therefore aimed to assess the effect of high-dose paracetamol on blood pressure in patients with acute stroke.

METHODS

We analyzed data of 540 patients admitted within 24 h of stroke onset who were randomized to treatment with either paracetamol (6 g daily) or placebo. Blood pressures were measured at 12, 24, and 48 h from the start of treatment. Changes in blood pressure from baseline in the two treatment groups and corresponding 95% confidence intervals (CI) were calculated with linear regression analysis. Adjustments for potential confounders were made with a multiple linear regression model.

RESULTS

Treatment with high-dose paracetamol was associated with a significant reduction in systolic blood pressure of 4.5 mm Hg (95% CI 0.6-8.5) at 12 h from the start of treatment. This effect was no longer present after 24 and 48 h.

CONCLUSION

High-dose paracetamol reduces not only body temperature but also systolic blood pressure in the first 12 h after start of treatment. Both effects may improve functional outcome after stroke, but this needs further study.

Mechanism of paracetamol-induced hypotension in critically ill patients: a prospective observational cross-over study

OBJECTIVE

To elucidate the mechanism of hypotension following intravenous administration of paracetamol (acetaminophen) to patients on the Intensive Care Unit.

DESIGN

Prospective observational cross-over study.

SETTING

Intensive Care Unit, University Hospital Královské Vinohrady, Prague, Czech Republic.

METHODS

Ventilated critically ill patients monitored by PiCCO and administered intravenous paracetamol at the same time were eligible for the study. We recorded haemodynamic indices, as well as core and peripheral temperatures, continuously for 3 h after the dose of paracetamol. Ranitidine was then used as a control drug known not to influence haemodynamics.

RESULTS

We included 6 subjects, and recorded 48 cycles of observations after administration of paracetamol, and 35 cycles after administration of the control drug. Haemodynamic parameters were not different at the baseline and administration of control drug did not result in any change in haemodynamics. After intravenous paracetamol, mean arterial pressure (MAP) dropped by 7% (p<0.001) with a nadir at the 19th minute. In 22 measurement cycles (45%) we noted >15% reduction in MAP with paracetamol. Analysis of these cycles suggests that hypotension with paracetamol can be caused by reduction of both cardiac index and systemic vascular resistance. In febrile cycles paracetamol caused narrowing of the gradient between central and peripheral temperatures suggesting skin vasodilation. These changes were not correlated to a change of systemic vascular resistance at any time point.

CONCLUSION

Hypotension with intravenous paracetamol in critically ill patients is caused by a reduction of both cardiac output and systemic vascular resistance. We did not demonstrate any relation between haemodynamic changes and antipyretic action of paracetamol. A possibility that cardiac output is reduced with paracetamol might be clinically important.

Analgesic efficacy and haemodynamic effects of nefopam in critically ill patients

BACKGROUND

Pain management is challenging in intensive care unit (ICU) patients. The analgesic efficacy, tolerance, and haemodynamic effects of nefopam have never been described in critically ill patients.

METHODS

In consecutive medical-surgical ICU patients who received 20 mg of nefopam i.v. over 30 min, we measured pain, Richmond Agitation Sedation Scale (RASS), respiratory parameters, and adverse drug events at T0 (baseline), T30 (end-of-infusion), T60, and T90 min. Haemodynamic variables were assessed every 15 min from T0 to T60 and T90. Pain was evaluated by the behavioural pain scale (BPS, 3-12) or by the self-reported visual numeric rating scale (NRS, 0-10) according to communication capacity.

RESULTS

Data were analysed for 59 patients. As early as T30, median NRS and BPS decreased significantly from T0 to a minimum level at T60 for NRS [5 (4-7) vs 1 (1-3), P<0.001] and T90 for BPS [5 (5-6) vs 3 (3-4), P<0.001]. No significant changes were detected for RASS, ventilatory frequency, or oxygen saturation. Increased heart rate and decreased mean arterial pressure, defined as a change ≥15% from baseline, were found in 29% and 27% of patients, respectively. For the 18 patients monitored, cardiac output increased by 19 (7-29)% and systemic vascular resistance decreased by 20 (8-28)%, both maximally at T30. Heat sensation, nausea/vomiting, sweating, and mouth dryness were found, respectively, in 6%, 9%, 22%, and 38% of patients.

CONCLUSIONS

A single slow infusion of nefopam is effective in critically ill patients who have moderate pain. The risk of tachycardia and increased cardiac output and also hypotension and decreased systemic vascular resistance should be known to evaluate the benefit/risk ratio of its prescription.

Haemodynamics of intravenous paracetamol in neonates

INTRODUCTION

Reports on the haemodynamics of intravenous (iv) paracetamol in adult intensive care were recently published. We therefore wanted to explore the haemodynamics of iv paracetamol in neonates.

METHODS

Retrospective, pooled analysis of heart rate (bpm) and blood pressure (mean, systolic, diastolic) observations collected during iv paracetamol pharmacokinetic studies in neonates. Heart rate and blood pressure were recorded just before and 30, 60, 120, 180, 240, 300 and 360 min after iv paracetamol (paired, ANOVA). Clinical characteristics in hypotensive (mean mmHg < gestational age, weeks) cases were compared with controls (Mann-Whitney U test).

RESULTS

Based on observations in 72 neonates, heart rate decreased from 145 (SD 20) to 138 (21), 141 (20), 137 (20), 137 (22), 140 (20), 139 (20) and 140 (21) bpm (paired p < 0.05, ANOVA p = 0.36). There were no changes in systolic and diastolic pressure, but mean arterial pressure decreased from 46 (7) to 43 (8) mmHg at 60 min (paired p < 0.05, ANOVA p = 0.75). Eight neonates developed hypotension. These patients had lower pre-administration arterial pressure (38 vs 47 mmHg, p < 0.05).

CONCLUSIONS

In a setting of open label administration to alleviate (procedural) pain, haemodynamic effects of iv paracetamol in neonates remained modest. We suggest considering impaired haemodynamics to be a relative contra-indication for iv paracetamol in neonates.