Low-dose dopamine: a physiologically based review

Relationship between intraoperative dopamine infusion and postoperative acute kidney injury in patients undergoing open abdominal aorta aneurysm repair

Background

Acute kidney injury (AKI) is one of the most common complications in patients undergoing open abdominal aortic aneurysm (AAA) repair. Dopamine has been frequently used in these patients to prevent AKI. We aimed to clarify the relationship between intraoperative dopamine infusion and postoperative AKI in patients undergoing open AAA repair.

Methods

We analyzed 294 patients who underwent open AAA repair at a single tertiary center from 2009 to 2018, retrospectively. The primary outcome was the incidence of postoperative AKI, determined by the Kidney Disease Improving Global Outcomes definition, after open AAA repair. Secondary outcomes included survival outcome, hospital and intensive care unit length of stay, and postoperative renal replacement therapy (RRT).

Results

Postoperative AKI occurred in 21.8% (64 out of 294 patients) The risk of postoperative AKI by intraoperative dopamine infusion was greater after adjusting for risk factors (odds ratio [OR] 2.56; 95% confidence interval [CI], 1.09–5.89; P = 0.028) and after propensity score matching (OR 3.22; 95% CI 1.12–9.24; P = 0.030). On the contrary, intraoperative norepinephrine use was not associated with postoperative AKI (use vs. no use; 19.3 vs. 22.4%; P = 0.615). Patients who used dopamine showed higher requirement for postoperative RRT (6.8 vs. 1.2%; P = 0.045) and longer hospital length of stay (18 vs. 16 days, P = 0.024).

Conclusions

Intraoperative dopamine infusion was associated with more frequent postoperative AKI, postoperative RRT, and longer hospital length of stay in patients undergoing AAA repair, when compared to norepinephrine. Further prospective randomized clinical trial may be necessary for this topic.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01624-6.

Management of Acute Kidney Injury Following Major Abdominal Surgery: A Contemporary Review

Acute kidney injury (AKI) is a frequent occurrence following major abdominal surgery and is independently associated with both in-hospital and long-term mortality, as well as with a higher risk of progressing to chronic kidney disease (CKD) and cardiovascular events. Postoperative AKI can account for up to 40% of in-hospital AKI cases. Given the differences in patient characteristics and the pathophysiology of postoperative AKI, it is inappropriate to assume that the management after noncardiac and nonvascular surgery are the same as those after cardiac and vascular surgery. This article provides a comprehensive review on the available evidence on the management of postoperative AKI in the setting of major abdominal surgery.

Acute Kidney Injury: From Diagnosis to Prevention and Treatment Strategies

Acute kidney injury (AKI) is characterized by an acute decrease in renal function that can be multifactorial in its origin and is associated with complex pathophysiological mechanisms. In the short term, AKI is associated with an increased length of hospital stay, health care costs, and in-hospital mortality, and its impact extends into the long term, with AKI being associated with increased risks of cardiovascular events, progression to chronic kidney disease (CKD), and long-term mortality. Given the impact of the prognosis of AKI, it is important to recognize at-risk patients and improve preventive, diagnostic, and therapy strategies. The authors provide a comprehensive review on available diagnostic, preventive, and treatment strategies for AKI.

The Perspective of the Intensivist on Inotropes and Postoperative Care Following Pediatric Heart Surgery: An International Survey and Systematic Review of the Literature

Introduction:

Inotropes are frequently being used in children undergoing heart surgery to prevent or treat low cardiac output syndrome (LCOS). There is only limited evidence that inotropes actually positively influence postoperative outcome. Our aim was to describe the current international practice variation in the use of inotropes following congenital heart surgery.

Methods:

We developed an online survey regarding the postoperative use of inotropes. We sent an invitation to all 197 registered members of the Pediatric Cardiac Intensive Care Society (PCICS) to participate in the survey. We also performed a systematic review of the literature.

Results:

Ninety-eight people (50%) responded, representing 62 international centers. Milrinone is routinely used perioperatively by 90 respondents (97%). Adrenaline/epinephrine is routinely used by 43%, dopamine by 36%, dobutamine by 11%, and levosimendan by 6%. Steroids are used routinely by 54% before initiating cardiopulmonary bypass. Vasopressin is used by 44% of respondents. The development of LCOS is monitored with lactate in 99% of respondents, physical examination (98%), intermittent mixed venous saturation (76%), continuous mixed venous saturation (13%), echocardiography (53%), core–peripheral temperature gap (29%), near-infrared spectrometry (25%), and 4% use cardiac output monitors (PiCCO, USCOM). To improve cardiac output, 42% add/increase milrinone, 37% add adrenaline, and 15% add dopamine. Rescue therapy is titrated individually, based on the patients’ pathophysiology. A systematic review of the literature failed to show compelling evidence with regard to the benefit of inotropes.

Conclusions:

Despite the lack of sufficient evidence, milrinone is used by the vast majority of caregivers following congenital heart surgery.

Systemic effects of low-dose dopamine during administration of cytarabine

Purpose Low-dose dopamine has been utilized to improve renal blood flow, urine output, and reduce drug-induced nephrotoxicity. The purpose of this study was to assess changes in renal function, cardiovascular adverse events, and neurologic toxicity in patients receiving cytarabine with or without low-dose dopamine. Methods A retrospective, single-center, cohort study of patients receiving cytarabine at 667 mg/m²/dose or greater, with or without dopamine at ≤5 mcg/kg/min. Cohorts were based upon initiation or absence of low-dose dopamine; cytarabine only, cytarabine + pre- and day of low-dose dopamine, and cytarabine + post-low-dose dopamine. Renal outcomes (urine output, serum creatinine, and creatinine clearance) were compared with baseline and between cohorts. Safety endpoints (arrhythmias, tachycardia, and neurotoxicity) were compared between cohorts based on low-dose dopamine exposure. Results There was no difference in urine output from baseline in all cohorts. Comparing cytarabine only and pre- and day of low-dose dopamine cohorts, there was no difference in urine output. In those receiving low-dose dopamine, there was no difference in serum creatinine and creatinine clearance from baseline. No arrhythmias were documented during the study period, and there was no difference in the incidence of tachycardia between groups (P = 0.66). Neurotoxicity was reported in three patients who were on low-dose dopamine. Conclusion Though variation existed in individual patients administered low-dose dopamine, the use of low-dose dopamine did not significantly impact renal function in this small sample at a single institution. In addition, low-dose dopamine did not negatively impact cardiovascular function.

Patients with chronic kidney disease

Chronic kidney disease (CKD) is a major public health problem worldwide. Roughly 1 in 10 adult Americans has CKD. These patients are at significant risk for excessive morbidity and mortality during the perioperative period. Given the health and cost burden of end-stage renal disease (ESRD), preventing or avoiding progression of CKD to ESRD is critical. Therefore, identifying risk factors and implementing risk mitigation strategies to prevent further deterioration of renal function during the perioperative period is of paramount importance. This article reviews patient risk stratification, preoperative evaluation and management, and perioperative interventions for renal protection.

Low-dose aminophylline for the treatment of neonatal non-oliguric renal failure-case series and review of the literature

OBJECTIVE

Aminophylline is a methylxanthine with multiple physiologic actions. At low doses, aminophylline can antagonize adenosine and improve renal function via increased glomerular filtration rate. Despite its clinical use, little data exists in neonates for this indication. Therefore, the objective of this report is to describe the impact of aminophylline on renal function indices in a series of neonates with acute renal failure.

MATERIALS AND METHODS

This was a retrospective chart review of 13 neonates with acute renal failure who received aminophylline during a 15-month study period. Aminophylline was administered at 1 mg/kg intravenously or orally every twelve hours. Forty-six percent (n = 6) of the patients received a 5 mg/kg loading dose before initiation of maintenance therapy. Most patients had already received other treatments for renal failure, including diuretics and dopamine.

RESULTS

Resolution of acute renal failure (with normalization of serum creatinine and blood urea nitrogen) was documented in 10 patients (77%). Four of the thirteen patients died from complications due to their prematurity. Failure of low-dose aminophylline was observed in 3 of the 4 patients who died.

CONCLUSIONS

Low-dose aminophylline in neonates with acute renal failure is associated with an improvement in renal function indices.

The Effects of Prenatal Protein Restriction on β-Adrenergic Signalling of the Adult Rat Heart during Ischaemia Reperfusion

A maternal low-protein diet (MLP) fed during pregnancy leads to hypertension in adult rat offspring. Hypertension is a major risk factor for ischaemic heart disease. This study examined the capacity of hearts from MLP-exposed offspring to recover from myocardial ischaemia-reperfusion (IR) and related this to cardiac expression of β-adrenergic receptors (β-AR) and their associated G proteins. Pregnant rats were fed control (CON) or MLP diets (n = 12 each group) throughout pregnancy. When aged 6 months, hearts from offspring underwent Langendorff cannulation to assess contractile function during baseline perfusion, 30 min ischemia and 60 min reperfusion. CON male hearts demonstrated impaired recovery in left ventricular pressure (LVP) and dP/dt_max (P < 0.01) during reperfusion when compared to MLP male hearts. Maternal diet had no effect on female hearts to recover from IR. MLP males exhibited greater membrane expression of β₂-AR following reperfusion and urinary excretion of noradrenaline and dopamine was lower in MLP and CON female rats versus CON males. In conclusion, the improved cardiac recovery in MLP male offspring following IR was attributed to greater membrane expression of β₂-AR and reduced noradrenaline and dopamine levels. In contrast, females exhibiting both decreased membrane expression of β₂-AR and catecholamine levels were protected from IR injury.

Goal-directed therapy in small animal critical illness

Monitoring critically ill patients can be a daunting task even for experienced clinicians. Goal-directed therapy is a technique involving intensive monitoring and aggressive management of hemodynamics in patients with high risk of morbidity and mortality. The aim of goal-directed therapy is to ensure adequate tissue oxygenation and survival. This article reviews commonly used diagnostics in critical care medicine and what the information gathered signifies and discusses clinical decision making on the basis of diagnostic test results. One example is early goal-directed therapy for severe sepsis and septic shock. The components and application of goals in early goal-directed therapy are discussed.

Inotropic drugs and their uses in critical care

The aim of this article was to provide a resource for critical care nurses wishing to further their understanding of inotropic drugs used in critical care. The physiology of cardiac output and blood pressure is examined along with an explanation of adrenergic receptors acted on by inotropes. Some common indications for inotropic therapy are discussed, along with essential patient monitoring and dose calculations to ensure safe therapeutic ranges are observed. Some of the most commonly used positive inotropes used in critical care environments are individually explored, providing indications and some of the latest research relating to their uses. Frequently, observed side effects of individual inotropes are also offered, enabling the nurse to maintain patient safety when administering these potent drugs. Some major nursing and professional issues related to inotrope therapy and medicine administration are discussed, as well as some recommended practices in renewing infusions.

Nephrotoxicity as a cause of acute kidney injury in children

Many different drugs and agents may cause nephrotoxic acute kidney injury (AKI) in children. Predisposing factors such as age, pharmacogenetics, underlying disease, the dosage of the toxin, and concomitant medication determine and influence the severity of nephrotoxic insult. In childhood AKI, incidence, prevalence, and etiology are not well defined. Pediatric retrospective studies have reported incidences of AKI in pediatric intensive care units (PICU) of between 8% and 30%. It is widely recognized that neonates have higher rates of AKI, especially following cardiac surgery, severe asphyxia, or premature birth. The only two prospective studies in children found incidence rates of 4.5% and 2.5% of AKI in children admitted to PICU, respectively. Nephrotoxic drugs account for about 16% of all AKIs most commonly associated with AKI in older children and adolescents. Nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, amphotericin B, antiviral agents, angiotensin-converting enzyme (ACE) inhibitors, calcineurin inhibitors, radiocontrast media, and cytostatics are the most important drugs to indicate AKI as significant risk factor in children. Direct pathophysiological mechanisms of nephrotoxicity include constriction of intrarenal vessels, acute tubular necrosis, acute interstitial nephritis, and-more infrequently-tubular obstruction. Furthermore, AKI may also be caused indirectly by rhabdomyolysis. Frequent therapeutic measures consist of avoiding dehydration and concomitant nephrotoxic medication, especially in children with preexisting impaired renal function.

Renal hemodynamic changes and renal functional reserve in children with type I diabetes mellitus

Increased glomerular filtration rate (GFR) has been implicated in the development of diabetic nephropathy. Large normal interindividual variations of GFR hamper the diagnosis of renal hemodynamic alterations. We examined renal functional reserve (RFR) in children with type 1 diabetes mellitus to assess whether hyperfiltration occurs. The renal hemodynamic response following dopamine infusion was examined in 51 normoalbuminuric diabetic children (7.7 +/- 3.6 years) with a mean duration of diabetes of 6.2 years and compared them with 34 controls. Mean baseline GFR in diabetic children did not differ from the control population (130.7 +/- 22.9 vs. 124.8 +/- 25 ml/min per 1.73 m(2)), whereas renal plasma flow was significantly lower (463.7 +/- 103.9 vs. 587.2 +/- 105 ml/min per 1.73 m(2), p < 0.001), and filtration fraction was increased (29 +/- 8 vs. 21 +/- 2%, p < 0.001), compared with controls. The mean RFR was lower (p < 0.001) than in control subjects (-0.77 +/- 23 vs. 21 +/- 8 ml/min per 1.73 m(2)). This study documents an increased filtration fraction and reduced or absent RFR in children with type 1 diabetes mellitus in the stage before apparent nephropathy. GFR values were within normal range. Although the reduced RFR and increased filtration fraction indicate the presence of hemodynamic changes, their relevance to the development of hyperfiltration and subsequent diabetic nephropathy remains unknown.

Surgical critical care: from old boundaries to new frontiers

The surgical specialty of critical care has evolved into a field where the surgeon manages complex medical and surgical problems in critically ill patients. As a specialty, surgical critical care began when acutely ill surgical patients were placed in a designated area within a hospital to facilitate the delivery of medical care. As technology evolved to allow for development of increasingly intricate and sophisticated adjuncts to care, there has been recognition of the importance of physician availability and continuity of care as key factors in improving patient outcomes. Guidelines and protocols have been established to ensure quality improvement and are essential to licensing by state and national agencies. The modern ICU team provides continuous daily care to the patient in close communication with the primary operating physician. While the ultimate responsibility befalls the primary physician who performed the preoperative evaluation and operative procedure, the intensivist is expected to establish and enforce protocols, guidelines and patient care pathways for the critical care unit. It is difficult to imagine modern surgical ICU care without the surgical critical care specialist at the helm.