Haemodynamic response to a small intravenous bolus injection of epinephrine in cardiac surgical patients:

Alterations to Kidney Physiology during Cardiopulmonary Bypass-A Narrative Review of the Literature and Practical Remarks

INTRODUCTION

According to different authors, cardiac surgery-associated acute kidney injury (CSA-AKI) incidence can be as high as 20-50%. This complication increases postoperative morbidity and mortality and impairs long-term kidney function in some patients. This review aims to summarize current knowledge regarding alterations to renal physiology during cardiopulmonary bypass (CPB) and to discuss possible nephroprotective strategies for cardiac surgeries. Relevant sections: Systemic and renal circulation, Vasoactive drugs, Fluid balance and Osmotic regulation and Inflammatory response.

CONCLUSIONS

Considering the available scientific evidence, it is concluded that adequate kidney perfusion and fluid balance are the most critical factors determining postoperative kidney function. By adequate perfusion, one should understand perfusion with proper oxygen delivery and sufficient perfusion pressure. Maintaining the fluid balance is imperative for a normal kidney filtration process, which is essential for preserving the intra- and postoperative kidney function.

FUTURE DIRECTIONS

The review of the available literature regarding kidney function during cardiac surgery revealed a need for a more holistic approach to this subject.

Bolus Vasopressor Use for Air Medical Rapid Sequence Intubation: The Vasopressor Intravenous Push to Enhance Resuscitation Trial

BACKGROUND

Rapid sequence intubation (RSI) may compromise perfusion because of the use of sympatholytic medications as well as subsequent positive pressure ventilation. The use of bolus vasopressor agents may reverse hypotension and prevent arrest.

METHODS

This was a prospective, observational study enrolling air medical patients with critical peri-RSI hypotension (systolic blood pressure [SBP] < 90 mm Hg) to receive either arginine vasopressin (aVP), 2 U intravenously every 5 minutes, for trauma patients or phenylephrine (PE), 200 μg intravenously every 5 minutes, for nontrauma patients. The main outcome measures included an increase in SBP, a reversal of hypotension, and the occurrence of dysrhythmia or hypertension (SBP > 160 mm Hg) within 20 minutes of vasopressor administration.

RESULTS

A total of 523 patients (344 aVP and 179 PE) were enrolled over 2 years. An increase in SBP was observed in 326 aVP patients (95%), with reversal of hypotension in 272 patients (79%). An increase in SBP was observed in 171 PE patients (96%), with reversal of hypotension in 148 patients (83%). A low rate of rebound hypertension was observed for both aVP and PE patients.

CONCLUSION

Both aVP and PE appear to be safe and effective for treating critical hypotension in the peri-RSI period.

Efficacy of bolus-dose epinephrine to manage hypotension in the prehospital setting

PURPOSE

Hypotension in the Emergency Department (ED) and the prehospital setting has been associated with significant morbidity and mortality. Limited literature exists exploring the utilization of intravenous (IV) bolus-dose epinephrine (BDE) by Emergency Medical Services (EMS).

METHODS

A retrospective review evaluated patients transported to an academic medical center who had received IV BDE by a single urban EMS system from 2016 to 2020. The primary outcome was to assess the influence IV BDE had on systolic blood pressure (SBP). Secondary objectives were to assess changes in heart rate (HR), the impact of dose variability on SBP, and the incidence of severe hypertension (SBP > 220 mmHg).

RESULTS

A total of 55 patients who received 96 administrations of IV BDE were included in the analysis. The most common individual dose was 10 μg (76.0%) and 45.5% received multiple doses. The median weight-based dose of BDE was 0.14 μg/kg. A significant increase in SBP (median 14.0 mmHg) was noted among all patients following BDE administration compared with baseline (p < 0.001). No significant difference was found in HR following BDE compared with baseline (p = 0.375). Those that received a BDE dose >10 μg were noted to have a significantly greater rise in SBP than those that received 10 μg (30.0 mmHg vs. 11.0 mmHg; p = 0.022). Similarly, patients that received a dose ≥0.2 μg/kg had a significantly greater increase in SBP compared with those that received <0.2 μg/kg (30.0 mmHg vs. 10.0 mmHg; p = 0.048). There were no incidences of severe hypertension following therapy.

CONCLUSION

The utilization of IV BDE in the prehospital setting for acute hypotension resulted in a significant rise in SBP. A dose-response relationship was noted both in terms of a flat-based dose and a weight-based dose, with higher doses yielding a greater change in SBP. Additional investigations are necessary to further explore the most appropriate dose of this agent in this setting and its influence, if any, on clinical outcomes.

Low-Dose Epinephrine Boluses for Acute Hypotension in the PICU

OBJECTIVES

To describe the use of low-dose bolus epinephrine in critically ill children during an acute hypotensive episode or prearrest condition.

DESIGN

Institutional Review Board approved, single-center, retrospective medical chart review.

SETTING

Large medical-surgical PICU within a freestanding, tertiary care children's hospital.

PATIENTS

Patients admitted to the PICU between June 1, 2015, and June 1, 2016, who received low-dose (≤ 5 µg/kg) IV bolus epinephrine.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Twenty-four resuscitation episodes (63 doses; 19 patients) were analyzed. Median age and weight of patients were 9 years (interquartile range, 1-15 yr) and 38.5 kg (interquartile range, 12-54.8 kg). Median Pediatric Risk of Mortality III score was 17 (interquartile range, 10-27). Mean epinephrine dose was 1.3 ± 1.1 µg/kg. Median number of doses per patient was two. If more than one dose was provided, median dosing interval was 6.5 minutes. Heart rate and mean arterial blood pressure were compared at the time of epinephrine administration and 1-4 minutes (median = 1 min) following administration. Heart rate changed from 130 ± 41 to 150 ± 33 beats/min (p < 0.05), and mean arterial blood pressure changed from 51 ± 17 to 75 ± 27 mm Hg (p < 0.001). Variability in mean arterial blood pressure response was observed; nonresponders required extracorporeal membrane oxygenation; 66% of doses resulted in up to 100% mean arterial blood pressure increase, and 21% of doses resulted in greater than 100% mean arterial blood pressure increase. Doses below 1 µg/kg were associated with a lower mean arterial blood pressure increase than doses between 1 and 5 µg/kg (mean percent change in mean arterial blood pressure = 6.6% vs 60%, respectively). Children less than or equal to 2 years old had the greatest percentage increase in heart rate and mean arterial blood pressure.

CONCLUSIONS

Provision of low-dose bolus epinephrine during periods of acute hypotension can result in a significant increase in mean arterial blood pressure and heart rate. This dosing strategy may provide temporary stabilization while other therapies are added or adjusted, but further research is needed.

Blood pressure reduction induced by low dose of epinephrine via different routes in rats

BACKGROUND

Epinephrine was recently shown to induce a hypotension episode. Activation of β₂-adrenoceptors with smooth muscle relaxation may be the underlying mechanism. This study investigated the effects of ICI 118551, a β₂-adrenoceptors antagonist, on epinephrine-induced blood pressure reduction via different administration routes in rats.

METHODS

A total of 144 Sprague Dawley rats were equally randomized into 3 groups (intranasal, intravenous, and intra-arterial administration), each with 4 subgroups: saline + saline, ICI 118551 + saline, saline + epinephrine, and ICI 118551 + epinephrine. All rats were anesthetized while spontaneously breathing. Epinephrine was administered at doses of 5 μg/kg via nose, 0.25 μg/kg via femoral vein, and 0.1 μg/kg via aorta. Mean arterial pressure and heart rate were monitored.

RESULTS

Mean arterial pressure decreased in all 3 saline + epinephrine subgroups after administration (P < 0.05), whereas it did not in other subgroups. Heart rate had no significant change in all subgroups.

CONCLUSIONS

Epinephrine-induced blood pressure reduction can be prevented by ICI 118551 in rats, suggesting that the activation of β₂-adrenoceptors contributes to blood pressure reduction.

Hemodynamic effects of epinephrine in healthy and hemorrhagic shock rats

OBJECTIVE

The aim of this study was to investigate the hemodynamic effects of epinephrine intravenous injection in healthy and hemorrhagic shock rats.

METHODS

Forty Sprague-Dawley male rats weighing 250 to 300 g were randomly assigned to 4 groups: group NE, healthy rats receiving epinephrine 2 μg/kg; group NS, healthy rats receiving normal saline; group SE, hemorrhagic shock rats receiving epinephrine 2 μg/kg; and group SS, hemorrhagic shock rats receiving normal saline. Mean arterial blood pressure (MAP) and heart rate (HR) were recorded at the following time points: 0 seconds (baseline), 5 seconds, 15 seconds, 30 seconds, 1 minute, 2 minutes, 4 minutes, 6 minutes, 8 minutes, and 10 minutes (T0-9) after intravenous injection.

RESULTS

There were no significant differences in MAP and HR at baseline between groups NS and NE or between groups SS and SE. Compared with the figures for baseline, MAP had no significant change at all time points in groups NS and SS. MAP increased at T1-9 in group SE (P < 0.01). MAP increased at T1-3 and decreased at T5-6 in group NE (P < 0.01). There was no significant change in HR in all groups after epinephrine or normal saline injection.

CONCLUSION

Epinephrine 2 μg/kg intravenous injection elicited biphasic changes in blood pressure, which included an initial increase and a subsequent decrease in healthy rats and induced a remarkable increase in blood pressure in hemorrhagic shock rats.

Hemodynamic effects of an intravenous bolus of epinephrine in healthy rats: A randomized, open-label, controlled pilot study

BACKGROUND

IV epinephrine is widely used in the treatment of shock to increase blood pressure (BP). However, whether it may also induce hypotension remains unknown.

OBJECTIVE

The aim of this randomized, open-label, controlled pilot study was to observe hemodynamic changes after an IV bolus of epinephrine in healthy rats.

METHODS

Healthy male Sprague-Dawley rats were randomized to 1 of 5 groups to receive IV epinephrine in doses of 0.5 μg/kg (group 1); 1 μg/kg (group 2); 2 μg/kg (group 3); 4 μg/kg (group 4); or 8 μg/kg (group 5). A sixth group received placebo (0.3 mL of normal saline) and served as the control. BP was monitored continuously. Mean arterial pressure (MAP) and heart rate (HR) were recorded at 0, 5, 15, and 30 seconds and 1, 2, 3, 4, 6, 8, 10, 12, 14, 16, 18, and 20 minutes after administration. The highest mean (SD) systolic BP (SBP) and the lowest mean (SD) diastolic BP (DBP) during this period were also recorded. Hypertension and hypotension were defined as BP increased or decreased > 10% from baseline.

RESULTS

Forty-two Sprague-Dawley rats were included in the study. The initial hypertension occurred at ~18 seconds in all epinephrine-treated groups (all, P < 0.01), and the subsequent hypotension occurred at mean (SD) 1.3 (0.5), 2.2 (0.4), 3.0 (0.6), and 3.4 (1.1) minutes in groups 2, 3, 4, and 5, respectively (all, P < 0.01). The highest mean (SD) SBP and the lowest mean (SD) DBP in groups 1, 2, 3, 4, 5, and the control group were 184 (12)/78 (11), 208 (14)/78 (10), 219 (18)/69 (14), 232 (17)/55 (11), 243 (16)/56 (15), and 148 (12)/91 (7) mm Hg, respectively, compared with baseline. HR decreased significantly at 15 seconds in groups 2 and 3, and at 5, 15, and 30 seconds in groups 4 and 5 (all, P < 0.01). One rat in group 4 and 1 rat in group 5 died due to treatment-related cerebral hemorrhage. The control group had no significant hemodynamic changes from baseline. Compared with the control group, MAP increased significantly at 5, 15, and 30 seconds and 1 minute in the epinephrine-treated groups and decreased significantly at 2, 3, and 4 minutes in group 3 and at 2, 3, 4, and 6 minutes in groups 4 and 5 (all, P < 0.05).

CONCLUSIONS

An IV bolus of epinephrine > 1 μg/kg was associated with biphasic changes in BP, including initial hypertension and subsequent hypotension, in these healthy rats. Future blinded and larger studies using lower doses are needed.

Hemodynamic changes due to infiltration of the scalp with epinephrine-containing lidocaine solution: a hypotensive episode before craniotomy

Epinephrine-containing lidocaine solution is commonly infiltrated on the scalp before craniotomy. But the hemodynamic changes caused by epinephrine-containing lidocaine solution have been less intensely studied. A prospective randomized double blind control study was designed to observe hemodynamic changes caused by epinephrine-containing lidocaine solution in neurosurgical operations under general anesthesia. One hundred twenty patients undergoing scheduled craniotomy were allocated randomly to 4 groups. All the patients received 1% lidocaine 16 mL with different dose (concentration) epinephrine: group 1 with 40 microg (2.5 microg/mL); group 2 with 80 microg (5 microg/mL); group 3 with 160 microg (10 microg/mL); and group 4 (control group) without epinephrine. mean arterial pressure (MAP) and heart rate were recorded at 30-second interval in 5 minutes after the beginning of local infiltration. In group 1, group 2, and group 3, the lowest MAP and the highest MAP during this period also were recorded. Bleeding was assessed after raising the craniotomy flap. Compared with the baseline, significant hemodynamic changes, particularly decrease in MAP with increase in heart rate at 1.5 minutes after the beginning of local infiltration, were observed in group 1, group 2, and group 3 (P<0.001), but not in group 4. The highest MAP increased significantly compared with the baseline in group 3 (P<0.05), but not in group 1 or group 2. Epinephrine-containing lidocaine solution reduced bleeding significantly (P<0.01). Infiltration with epinephrine-containing lidocaine solution elicits temporary but significant hemodynamic changes including hypotension before craniotomy. Commonly clinically used concentrations of epinephrine (2.5 to 10 microg/mL) can reduce the bleeding on the scalp.

Cardiovascular responses in patients with acute allergic reactions treated with parenteral epinephrine

The present study describes the cardiovascular responses to epinephrine (Epi) given into the arm, in adult patients with acute allergic reactions, and the differential responses to subcutaneous (SC) and intramuscular (IM) administration. Sixty-three adult patients were treated with Epi administered SC or IM after H1 and H2 receptor blockade. Heart rate and blood pressure (BP) were then measured for 20 minutes. Changes in heart rate and BP variables were analyzed. Pulse pressure and systolic BP showed increases with time. Diastolic BP also showed a modestly decreasing values over time. Heart rates did not change. Time-related changes between IM and SC Epi treatment were not observed. Sex influenced timed BP values and a significant sex by time effect was observed. In subset analysis, only male patients showed an overall time effect for BP variables, especially pulse pressure. In conclusion, adults with acute allergic syndromes treated with arm-injected Epi show a modest but definite increase in pulse pressure and systolic BP. This pattern is observed more in males. Heart rate and blood pressure differences between IM and SC arm-injected Epi treatments do not appear to be significant.