Improved Patient Outcomes by Normalizing Sympathovagal Balance: Midodrine and Parasympathetic and Sympathetic Monitoring

A function of the Parasympathetic and Sympathetic (P&S) nervous systems is to maintain proper tissue perfusion, including of the heart and brain upon head-up postural change standing. Orthostatic dysfunction (OD) is associated with pooling of blood in the lower extremities, insufficient vascular support of the heart, and poor brain perfusion. Abnormal P&S responses to standing help to guide therapy for the individual patient. Midodrine is often the primary recommendation to correct P&S dysfunction upon standing. P&S Monitoring (Physio PS, Inc, Atlanta, GA) differentiates OD-subtypes in 2727 cardiology patients, serially tested. P&S Monitoring non-invasively, independently, and simultaneously measures P&S activity, including the normal P-decrease followed by an S-increase with head-up postural change (standing). S-Withdrawal (SW) and P-Excess (PE) are two types of autonomic dysfunction that are associated with OD. SW differentiates OD from Syncope (an S- excess with stand, e.g. Vasovagal Syncope). PE often masks SW by inflating the S-response to stand. OD based solely on BP and HR responses to provocation remains difficult to differentiate, especially early in its development and difficult to track upon follow-up. The latter is important to ensure relief of not only the abnormal BP response to stand (e.g. Orthostatic Hypotension) or HR (e.g. Postural Orthostatic Tachycardia Syndrome) but the SW or PE as well. SW underlies the majority of Dysautonomia patients with lightheadedness (whether masked or not, 82.0%, p=0.0061). Midodrine relieves SW and ultimately Lightheadedness and associated symptoms within 9 months (75.4%, p=0.0323). P&S Monitoring provides more information, enabling earlier and more specific diagnosis and therapy for improved patient outcomes. P&S dysfunction upon standing may be most well relieved by very low doses of oral vasoactive medications such as Midodrine (Proamatine), Mestinon (Pyridostigmine), or Northera (Droxidopa). In this study we focus on Midodrine.

PERIPHERAL INOTROPES IN CRITICALLY ILL CHILDREN - IS IT SAFE?

ABSTRACTMany children needing paediatric intensive care units care require inotropes, which are started peripherally prior to securing a central venous access. However, many hospitals in low- and middle-income countries may not have access to central lines and the vasoactive medications are frequently given through a peripheral venous access.AimThe aim of our study was to estimate the safety of peripheral vasoactive inotropes in children.MethodsChildren requiring peripheral vasoactive medications were included in this study. We retrospectively collected data at two time points on use and complications of peripheral vasoactive medications.ResultsEighty-four children (51 pre-COVID era and 33 COVID pandemic) received peripheral vasoactive medications. Only 3% of children (3/84) developed extravasation injury, all of whom recovered completely.ConclusionsResults from our study suggest that extravasation injury due to peripheral inotrope infusion is very low (3%) and it can be safely administered in children at a diluted concentration.

Peripheral Inotropes in Critically Ill Children: Is It Safe?

Many children needing pediatric intensive care units care require inotropes, which are started peripherally prior to securing a central venous access. However, many hospitals in low- and middle-income countries (LMIC) may not have access to central lines and the vasoactive medications are frequently given through a peripheral venous access. Aim: The aim of our study was to describe the role of peripheral vasoactive inotropes in children. Methods: Children requiring peripheral vasoactive medications were included in this study. We retrospectively collected data at 2 time points on use and complications of peripheral vasoactive medications. Results: Eighty-four children (51 pre-COVID era and 33 COVID pandemic) received peripheral vasoactive medications. Only 3% of children (3/84) developed extravasation injury, all of whom recovered completely. Conclusions: Results from our study suggest that extravasation injury due to peripheral inotrope infusion is very low (3%) and it may be safely administered in children at a diluted concentration.

Hemodynamic Effects of Cardiovascular Medications in a Normovolemic and Hemorrhaged Yorkshire-cross Swine Model

The Yorkshire-cross swine model is a valuable translational model commonly used to study cardiovascular physiologyand response to insult. Although the effects of vasoactive medications have been well described in healthy swine, the effects of these medications during hemorrhagic shock are less studied. In this study, we sought to expand the utility of the swine model by characterizing the hemodynamic changes that occurred after the administration of commonly available vasoactive medications during euvolemic and hypovolemic states. To this end, we anesthetized and established femoral arterial,central venous, and pulmonary arterial access in 15 juvenile Yorkshire-cross pigs. The pigs then received a series of rapidlymetabolized but highly vasoactive medications in a standard dosing sequence. After completion of this sequence, each pigunderwent a 30-mL/kg hemorrhage over 10 min, and the standard dosing sequence was repeated. We then used standard statisticaltechniques to compare the effects of these vasoactive medications on a variety of hemodynamic parameters betweenthe euvolemic and hemorrhagic states. All subjects completed the study protocol. The responses in the hemorrhagic state wereoften attenuated or even opposite of those in the euvolemic state. For example, phenylephrine decreased the mean arterialblood pressure during the euvolemic state but increased it in the hemorrhagic state. These results clarify previously poorlydefined responses to commonly used vasoactive agents during the hemorrhagic state in swine. Our findings also demonstratethe need to consider the complex and dynamic physiologic state of hemorrhage when anticipating the effects of vasoactivedrugs and planning study protocols.

Implementing a Goal-Directed Therapy Protocol for Fluid Resuscitation in the Cardiovascular Intensive Care Unit

Background Balancing fluid administration and titration of vasoactive medications is critical to preventing postoperative complications in cardiac surgical patients. Objective To evaluate the impact of implementing a goal-directed therapy protocol in the cardiovascular intensive care unit on total intravenous fluids administered on the day of surgery, rates of acute kidney injury, and hospital length of stay. Methods A fluid resuscitation protocol using dynamic assessment of fluid responsiveness with stroke volume index was developed, and nurses were prepared for its implementation using simulation training. Results After implementation of the new protocol, the total amount of intravenous fluids administered on the day of surgery was significantly reduced (P = .003). There were no significant changes in hospital length of stay (P = .83) or rates of acute kidney injury (P = .86). There were significant increases in nurses’ knowledge of (P < .001) and confidence in (P < .001) fluid resuscitation and titration of vasoactive medications after simulation training. Conclusions Use of a fluid resuscitation protocol resulted in a reduction in the amount of intravenous fluids administered on the day of surgery. The simulation training increased nurses’ knowledge of and confidence in fluid resuscitation and titration of vasoactive medications.