Effect of Phenylephrine Push Before Continuous Infusion Norepinephrine in Patients With Septic Shock

Noninvasive assessment of human microvascular function in health and disease using incident dark-field microscopy

Reduced peripheral microvascular reactivity is associated with an increased risk for major adverse cardiac events (MACEs). Tools for noninvasive assessment of peripheral microvascular function are limited, and existing technology is poorly validated in both healthy populations and patients with cardiovascular disease (CVD). Here, we used a handheld incident dark-field imaging tool (CytoCam) to test the hypothesis that, compared with healthy individuals (no risk factors for CVD), subjects formally diagnosed with coronary artery disease (CAD) or those with ≥2 risk factors for CAD (at risk) would exhibit impaired peripheral microvascular reactivity. A total of 17 participants (11 healthy, 6 at risk) were included in this pilot study. CytoCam was used to measure sublingual microvascular total vessel density (TVD), perfused vessel density (PVD), and microvascular flow index (MFI) in response to the topical application of acetylcholine (ACh) and sublingual administration of nitroglycerin (NTG). Baseline MFI and PVD were significantly reduced in the at-risk cohort compared with healthy individuals. Surprisingly, following the application of acetylcholine and nitroglycerin, both groups showed a significant improvement in all three microvascular perfusion parameters. These results suggest that, despite baseline reductions in both microvascular density and perfusion, human in vivo peripheral microvascular reactivity to both endothelial-dependent and -independent vasoactive agents remains intact in individuals with CAD or multiple risk factors for disease.NEW & NOTEWORTHY To our knowledge, this is the first study to comprehensively characterize in vivo sublingual microvascular structure and function (endothelium-dependent and -independent) in healthy patients and those with CVD. Importantly, we used an easy-to-use handheld device that can be easily translated to clinical settings. Our results indicate that baseline microvascular impairments in structure and function can be detected using the CytoCam technology, although reactivity to acetylcholine may be maintained even during disease in the peripheral microcirculation.

Implementation and Evaluation of Weight-Based Vasopressors in Intensive Care Units

Background: Vasopressors, including norepinephrine, epinephrine, and phenylephrine are commonly used to maintain mean arterial pressure (MAP) in critically ill patients. Despite their frequent use, the optimal dosing strategy for vasopressors remains understudied. Objective: The purpose of this study is to evaluate the implementation of a weight-based (WB) dosing strategy using ideal body weight compared to a non-weight-based (NWB) dosing strategy for vasopressors in critically ill patients. Methods: This is a retrospective chart review of patients admitted to intensive care units receiving vasopressor medications for greater than or equal to 4 hours. Patients received either an NWB or a WB vasopressor dosing strategy. The primary endpoint was the time to achieve goal MAP. Results: This study included 153 patients in the NWB vasopressor dosing group and 183 in the WB dosing group. The median time to achieve goal MAP in the NWB group was 24 minutes versus 21 minutes in the WB group (P = 0.1713). There were no significant differences in secondary outcomes including number of vasoactive agents required, hospital length of stay, and duration of mechanical ventilation. Subgroup analysis of patients with extremes of body mass index did not show a difference in time to achieve goal MAP. In a subgroup analysis of patients with septic shock, a higher percentage of patients in the WB group received corticosteroids than the NWB group patients (14% vs. 54%; P ≤ 0.001). Conclusion and relevance: There was no difference in time to achieve goal MAP when using a WB or NWB vasopressor dosing approach. Institutions should employ a consistent dosing strategy for vasopressors with either an NWB or WB approach.

Preparation/administration of push-dose versus continuous infusion epinephrine and phenylephrine: A simulation

BACKGROUND

Hypotension is a common problem in the emergency department (ED) and intensive care unit (ICU) and can increase risk for poor outcomes. Many EDs/ICUs utilize epinephrine and phenylephrine to treat hypotension and these medications are most often administered as a continuous infusion (CI). Push-dose (PD) is the administration of small medication doses as intermittent intravenous pushes (IVPs). There is limited information comparing the time required to prepare and administer PD versus CI and errors have been reported when preparing and administering these medications at bedside. This simulation study sought to estimate preparation and administration times and preparation and errors with PD and CI epinephrine and phenylephrine when prepared by an ED/ICU pharmacist.

METHODS

This crossover simulation study took place in a simulation center at an academic medical center and utilized a multi-venous intravenous training arm kit equip with an 18-gauge intravenous line, an extension tubing set, and a luer-lock adapter. The primary outcome was total preparation and administration time in seconds. The secondary outcome was major preparation and administration errors, defined as errors causing a five-fold or greater overdose.

RESULTS

In total, 16 pharmacists participated, including nine ED and seven ICU pharmacists. PD had faster total preparation and administration time and administration time, but not preparation time; PD showed an approximate 70 s decrease in total preparation and administration time versus CI. PD had more major preparation and administration errors and six PD preparations (18.8%, 6/32) had at least one major preparation and administration error. CI, on the other hand, had no major preparation and administration errors.

DISCUSSION

This simulation found faster total preparation and administration time with PD versus CI epinephrine and phenylephrine, but also found that PD had more major preparation and administration errors. Dilutional errors during medication preparation were the cause of 83.3% (5/6) of our overdoses.

CONCLUSION

This simulation study showed that ED/ICU pharmacists had faster median total preparation and administration times for PD epinephrine and phenylephrine versus CI, but PD also had more preparation and administration errors.

Norepinephrine combined with phenylephrine versus norepinephrine in patients with septic shock: a retrospective cohort study

BACKGROUND

Phenylephrine (PE) and norepinephrine (NE) may be used to maintain adequate blood pressure and tissue perfusion in patients with septic shock, but the effect of NE combined with PE (NE-PE) on mortality remains unclear. We hypothesized that NE-PE would not inferior to NE alone for all-cause hospital mortality in patients with septic shock.

METHODS

This single-center, retrospective cohort study included adult patients with septic shock. According to the infusion type, patients were divided into the NE-PE or NE group. Multivariate logistic regression, propensity score matching and doubly robust estimation were used to analyze the differences between groups. The primary outcome was the all-cause hospital mortality rate after NE-PE or NE infusion.

RESULTS

Among 1, 747 included patients, 1, 055 received NE and 692 received NE-PE. For the primary outcome, the hospital mortality rate was higher in patients who received NE-PE than in those who received NE (49.7% vs. 34.5%, p < 0.001), and NE-PE was independently associated with higher hospital mortality (odds ratio = 1.76, 95% confidence interval = 1.36-2.28, p < 0.001). Regarding secondary outcomes, patients in the NE-PE group had longer lengths of stay in ICU and hospitals. Patients in the NE-PE group also received mechanical ventilation for longer durations.

CONCLUSIONS

NE combined with PE was inferior to NE alone in patients with septic shock, and it was associated with a higher hospital mortality rate.

The incidence of cardiovascular instability in patients receiving various vasopressor strategies for peri-intubation hypotension

INTRODUCTION

Patients frequently experience hypotension in the peri-intubation period. This can be due to the underlying disease process, physiologic response to the intervention, or adverse effect from medications. With the heterogeneity in cause for hypotension, the duration can also be short or prolonged. Initiation of vasopressors for peri-intubation hypotension includes various strategies using continuous infusion norepinephrine (NE) or push-dose phenylephrine (PDPE) to obtain goal mean arterial pressure. There is a paucity of data describing cardiovascular stability outcomes in patients receiving vasopressors for peri-intubation hypotension.

METHODS

This is a retrospective cohort study including emergency department patients across three academic medical centers and smaller health system sites who received vasopressors for hypotension within 30 min of intubation. Patients were matched based on factors likely to influence vasopressor selection and were divided into groups if they received PDPE alone, continuous infusion NE alone, or PDPE followed by continuous infusion NE. The primary outcome was a composite of the incidence of hypotension (systolic blood pressure < 90 mmHg), bradycardia (HR < 60 beats per minute), and cardiac arrest within 2 h following initiation of vasopressors.

RESULTS

Screening occurred for 2518 patients, with 105 patients undergoing matching. Mean time to vasopressor initiation was 10 min following intubation. The composite primary outcome was not statistically different between groups and occurred 88.6%, 80.0%, and 88.6% in the NE, PDPE, and PDPE+NE groups, respectively. A subgroup analysis of patients with an ED diagnosis of sepsis or septic shock were more likely to receive PDPE before starting continuous infusion NE (41.3% vs. 27.1%, p = 0.075) and more frequently experienced the primary composite outcome (p = 0.045) but was not correlated with vasopressor strategy (p = 0.55).

DISCUSSION

Cardiovascular instability following vasopressor initiation for peri-intubation hypotension was no different depending on the selected vasopressor strategy. This held true in patients with a sepsis or septic shock diagnosis. Selection of vasopressors should continue to include patient specific factors and product availability.

A Review of Push-Dose Vasopressors in the Peri-operative and Critical Care Setting

During hospitalization, the risk of hypotension and associated sequelae remain important considerations for patient outcomes. The use of push-dose vasopressors (PDP) outside of the operating room has increased in recent years to combat the negative effects of hypotension. This narrative review evaluates the utility of PDP in its traditional perioperative setting as well as in areas of increasing use such as the emergency department and intensive care unit. Articles evaluating PDP highlight successful increases in blood pressure with all agents but differ in rates of adverse events and most lack direct comparison of PDP agents in regard to safety and efficacy. Agents utilized as PDP, including epinephrine, phenylephrine, norepinephrine, vasopressin, and ephedrine vary in mechanism of action, onset of action, and duration of action. These variations in pharmacology along with published literature may lead to differences in the preferred PDP for various clinical scenarios. Many adverse events associated with PDP have been due to dosing errors highlighting the importance of education surrounding the use of these agents. Additional research is necessary to further elucidate the risks and benefits of PDP in clinical practice, and to determine which PDP is truly preferred. Careful consideration should be given when determining the appropriateness of this administration method of vasopressors in various clinical scenarios.

[Vasoactive drugs in the treatment of septic shock]

Septic shock is a high mortality complication frequently associated with sepsis. Early initiation of vasopressor treatment, even before completion of initial fluid resuscitation, is a determining factor in prognosis. In this sense, norepinephrine continues to be the drug of first choice, although there is increasing evidence of benefit combining it with other non-adrenergic drugs, such as vasopressin, instead of escalating norepinephrine doses. The pathophysiology of septic shock is multifactorial, and sometimes is associated with a situation of myocardial dysfunction that contributes to hemodynamic instability. It is essential to identify this situation since it worsens the prognosis and may benefit from combined treatment with inotropic drugs. There are novel vasoactive agents under study, more selective than the classic ones that in a next future could help to design more individualized and precise treatments. In the present work, the current knowledge about vasoactive drugs and their use in the management of septic shock is summarized according to the most recent scientific evidence.

Comparison of push-dose phenylephrine and epinephrine in the emergency department

BACKGROUND

There is limited evidence to support the efficacy and safety of push-dose vasopressor (PDP) use outside of the operating room (OR). Specifically, there are few head-to-head comparisons of different PDP in these settings. The purpose of this study was to compare the efficacy and safety of push-dose phenylephrine (PDP-PE) and epinephrine (PDP-E) in the Emergency Department (ED).

METHODS

This retrospective, single-center study evaluated adults given PDP-PE or PDP-E in the ED from May 2017 to November 2020. The primary outcome was a change in heart rate (HR). Secondary outcomes included changes in blood pressure, adverse effects, dosing errors, fluid and vasopressor requirements, ICU and hospital lengths of stay (LOS), and in-hospital mortality.

RESULTS

Ninety-six patients were included in the PDP-PE group and 39 patients in the PDP-E group. Median changes in HR were 0 [-7, 6] and - 2 [-15, 5] beats per minute (BPM) for PDP-PE and PDP-E, respectively (p = 0.138). PDP-E patients had a greater median increase in systolic blood pressure (SBP) (33 [24, 53] vs. 26 [8, 51] mmHg; p = 0.049). Dosing errors occurred more frequently in patients that received PDP-E (5/39 [12.8%] vs. 2/96 [2.1%]; p = 0.021). PDP-E patients more frequently received continuous epinephrine infusions before and after receiving PDP-E. There were no differences in adverse effects, fluid requirements, LOS, or mortality.

CONCLUSION

PDP-E provided a greater increase in SBP compared to PDP-PE. However, dosing errors occurred more frequently in those receiving PDP-E. Larger head-to-head studies are necessary to further evaluate the efficacy and safety of PDP-E and PDP-PE.