Vasopressin in Sepsis and Other Shock States: State of the Art

This review of the use of vasopressin aims to be comprehensive and highly practical, based on the available scientific evidence and our extensive clinical experience with the drug. It summarizes controversies about vasopressin use in septic shock and other vasodilatory states. Vasopressin is a natural hormone with powerful vasoconstrictive effects and is responsible for the regulation of plasma osmolality by maintaining fluid homeostasis. Septic shock is defined by the need for vasopressors to correct hypotension and lactic acidosis secondary to infection, with a high mortality rate. The Surviving Sepsis Campaign guidelines recommend vasopressin as a second-line vasopressor, added to norepinephrine. However, these guidelines do not address specific debates surrounding the use of vasopressin in real-world clinical practice.

Risk factors of gastrointestinal bleeding after cardiopulmonary bypass in children: a retrospective study

Background

During cardiac surgery that involved cardiopulmonary bypass (CPB) procedure, gastrointestinal (GI) system was known to be vulnerable to complications such as GI bleeding. Our study aimed to determine the incidence and risk factors associated with GI bleeding in children who received CPB as part of cardiac surgery.

Methods

This retrospective study enrolled patients aged <18 years who underwent cardiac surgery with CPB from 2013 to 2019 at Shanghai Children's Medical Center. The primary outcome was the incidence of postoperative GI bleeding in children, and the associated risk factors with postoperative GI bleeding episodes were evaluated.

Results

A total of 21,893 children who underwent cardiac surgery with CPB from 2013 to 2019 were included in this study. For age distribution, 636 (2.9%) were neonates, 10,984 (50.2%) were infants, and 10,273 (46.9%) were children. Among the 410 (1.9%) patients with GI bleeding, 345 (84.2%) survived to hospital discharge. Incidence of GI bleeding in neonates, infants and children were 22.6% (144/636), 2.0% (217/10,984) and 0.5% (49/10,273), respectively. The neonates (22.6%) group was associated with highest risk of GI bleeding. Patients with GI bleeding showed longer length of hospital stays (25.8 ± 15.9 vs. 12.5 ± 8.9, P < 0.001) and higher mortality (15.9% vs. 1.8%, P < 0.001). Multivariate logistic regression analysis showed that age, weight, complicated surgery, operation time, use of extracorporeal membrane oxygenation (ECMO), low cardiac output syndrome (LCOS), hepatic injury, artery lactate level, and postoperative platelet counts were significantly associated with increased risk of GI bleeding in children with congenital heart disease (CHD) pediatric patients that underwent CPB procedure during cardiac surgery.

Conclusion

The study results suggest that young age, low weight, long operation time, complicated surgery, use of ECMO, LCOS, hepatic injury, high arterial lactate level, and low postoperative platelet counts are independently associated with GI bleeding after CPB in children.

A Randomized Porcine Study in Low Cardiac Output of Vasoactive and Inotropic Drug Effects on the Gastrointestinal Tract

BACKGROUND

Splanchnic vasodilation by inodilators is an argument for their use in critical cardiac dysfunction. To isolate peripheral vasoactivity from inotropy, such drugs were investigated, and contrasted to vasopressors, in a fixed low cardiac output (CO) model resembling acute cardiac dysfunction effects on the gastrointestinal tract. We hypothesized that inodilators would vasodilate and preserve the aerobic metabolism in the splanchnic circulation in low CO.

METHODS

In anesthetized pigs, CO was lowered to 60% of baseline by partial inferior caval vein balloon inflation. The animals were randomized to placebo (n = 8), levosimendan (24 μg kg-1 bolus, 0.2 μg kg-1 min-1, n = 7), milrinone (50 μg kg-1 bolus, 0.5 μg kg-1 min-1, n = 7), vasopressin (0.001, 0.002 and 0.006 U kg-1 min-1, 1 h each, n = 7) or norepinephrine (0.04, 0.12, and 0.36 μg kg-1 min-1, 1 h each, n = 7). Hemodynamic variables including mesenteric blood flow were collected. Systemic, mixed-venous, mesenteric-venous, and intraperitoneal metabolites were analyzed.

RESULTS

Cardiac output was stable at 60% in all groups, which resulted in systemic hypotension, low superior mesenteric artery blood flow, lactic acidosis, and increased intraperitoneal concentrations of lactate. Levosimendan and milrinone did not change any circulatory variables, but levosimendan increased blood lactate concentrations. Vasopressin and norepinephrine increased systemic and mesenteric vascular resistances at the highest dose. Vasopressin increased mesenteric resistance more than systemic, and the intraperitoneal lactate concentration and lactate/pyruvate ratio.

CONCLUSION

Splanchnic vasodilation by levosimendan and milrinone may be negligible in low CO, thus rejecting the hypothesis. High-dose vasopressors may have side effects in the splanchnic circulation.

Risk Factors Associated with In-Hospital Mortality for Patients with Acute Abdomen After Cardiac Surgery

OBJECTIVES

Management of acute abdomen (AA) differs due to the heterogeneity of underlying pathophysiology. Complications of AA and its overall outcome after cardiac surgery are known to be associated with poor results. The aim of this retrospective analysis was to evaluate risk factors for AA in patients undergoing cardiac surgery.

METHODS

Between December 2011 and December 2014, a total of 131 patients with AA after cardiac surgery were identified and retrospectively analyzed using our institutional database. Statistical analysis of risk factors concerning in-hospital mortality of mentioned patient cohort was performed using IBM SPSS Statistics.

RESULTS

Overall in-hospital mortality was 54.2% (71/131). Analyzing in-hospital non-survivors (NS) versus in-hospital survivors (S) peripheral artery disease (28.2% vs. 11.7%; p = 0.03), the need for assist device therapy (33.8% vs. 16.7%; p = 0.03) and the requirement of hemodialysis (67.6% vs. 23.3%; p < 0.01) were significantly higher in NS. Furthermore, lactic acid values at onset of symptoms were shown to be significantly higher in NS (5.7 ± 5.7 mmol/L vs. 2.8 ± 2.9 mmol/L; p < 0.01). Assured diagnosis of mesenterial ischemia was strongly associated with worse outcome (odds ratio 10.800, 95% confidence interval 2.003-58.224; p = 0.006).

CONCLUSION

In conclusion, in critically ill patients after performed cardiac surgery peripheral vascular disease, need for supportive hemodynamic assist device systems and occurrence of renal failure are risk factors associated with worsen outcome. Additionally, rise of lactic acid could potentially be associated with onset of intestinal malperfusion and should be taken into account in therapeutic decisions preventing fatal mesenterial ischemia.

Review article: the pharmacological causes of colon ischaemia

BACKGROUND

Colon ischaemia is the most common ischaemic disorder of the gastrointestinal system, can affect any segment of the colon, and may present with a range of symptoms. Diagnosis can be challenging due to symptom overlap with other conditions, varied aetiology, and often rapid and self-resolving course.

AIM

To review comprehensively the literature regarding the pharmacological aetiologies of colonic ischaemia to enhance the understanding of the various mechanisms of disease, presentations, distribution, and outcomes.

METHODS

A PubMed search for "colon ischaemia" and "ischaemic colitis" alone as well as in combination with various known pharmacologic causes was performed. Only the highest quality and relevant literature was included in this review. The quality of the literature for each association was rated by the authors and a consensus was made when discrepancies were encountered. Only associations that were deemed "moderate" or "strong" were included.

RESULTS

The literature considering pharmacologically associated colonic ischaemia is diverse, lacks codification and is characterised by numerous case reports and case series. Constipation-inducing drugs, digoxin, hormonal therapies, illicit drugs, immunomodulators, laxatives, and NSAIDs were strongly associated with colonic ischaemia. Antimicrobials, appetite suppressants, chemotherapies, decongestants, diuretics, ergot alkaloids, serotonin agents, statins, and vasopressor agents were moderately associated.

CONCLUSIONS

Patients presenting with abdominal pain, diarrhoea, or bloody stool need to be evaluated for the possibility of this condition and treated accordingly. Timely diagnosis is necessary to improve patient outcomes. This review aims to increase awareness among clinicians regarding the presentation of pharmacologically induced colonic ischaemia.

Enhanced coronary arteriolar contraction to vasopressin in patients with diabetes after cardiac surgery

OBJECTIVE

Cardioplegic arrest (CP) and cardiopulmonary bypass (CPB) are associated with vasomotor dysfunction of coronary arterioles in patients with diabetes (DM) undergoing cardiac surgery. We hypothesized that DM may up-regulate vasopressin receptor expression and alter the contractile response of coronary arterioles to vasopressin in the setting of CP/CPB.

METHODS

Right atrial tissue samples of patients with DM and without (ND) (n = 8 in each group) undergoing cardiac surgery were harvested before and after CP/CPB. The isolated coronary arterioles (80-150 μm) dissected from the harvested right atrial tissue samples were cannulated and pressurized (40 mm Hg) in a no-flow state. The changes in diameter were measured with video microscopy. The protein expression/localization of vasopressin 1A receptors (V1A) and vasopressin 1B receptors (V1B) in the atrial tissue were measured by immune-blotting and immunohistochemistry.

RESULTS

The pre-CP/CPB contractile responses of the coronary arterioles to vasopressin were significantly increased post-CP/CPB in both the ND and DM groups. This effect was more pronounced in the vessels from patients in the DM group than that of vessels from patients in the ND group (P < .05). Vasopressin-induced contractile response of the coronary arterioles was inhibited in the presence of the specific V1A antagonist SR 49059 (10-7 M) in both ND and DM vessels (P < .05). The post-CP/CPB protein levels of V1A were significantly increased compared with pre-CP/CPB values in both the ND and DM groups (P < .05), whereas this increase was greater in DM than that of ND (P < .05). Immunohistochemistry staining further indicates that V1B were mainly expressed in the myocardium but not in vascular smooth muscle.

CONCLUSIONS

CP/CPB and DM are both associated with up-regulation in V1 receptor expression/localization in human myocardium. Vasopressin may induce coronary arteriolar constriction via V1A. This alteration may lead to increased coronary arteriolar spasm in patients with DM undergoing CP/CPB and cardiac surgery.

Establishment of Predictive Models for Nonocclusive Mesenteric Ischemia Comparing 8,296 Control with 452 Study Patients

OBJECTIVE

The aim of this study was to develop clinical preoperative, intraoperative, and postoperative scores for early identification of patients who are at risk of nonocclusive mesenteric ischemia (NOMI).

DESIGN

A retrospective analysis.

SETTING

Single center.

PARTICIPANTS

From January 2008 to December 2014, all patients from the Department of Thoracic and Cardiovascular Surgery were included on the basis of the hospital database.

INTERVENTIONS

All mesenteric angiographically identified NOMI patients were compared with non-NOMI patients.

MEASUREMENTS AND MAIN RESULTS

The study population of 8,748 patients was randomized into a cohort for developing the scores (non-NOMI 4,214 and NOMI 235) and a cohort for control (non-NOMI 4,082 and NOMI 217). Risk factors were identified using forward and backward Wald test and were included in the predictive scores for the occurrence of NOMI. C statistic showed that the scores had a high discrimination for the prediction of NOMI preoperatively (C statistic 0.79; p < 0.001), intraoperatively (C statistic 0.68; p < 0.001), and postoperatively (C statistic 0.85; p < 0.001). A combination of the preoperative, intraoperative, and postoperative risk scores demonstrated the highest discrimination (C statistic 0.87; p < 0.001). The combined score included the following risk factors: renal insufficiency (preoperative); use of cardiopulmonary bypass and intra-aortic balloon pump support (intraoperative); and reexploration for bleeding, renal replacement therapy, and packed red blood cells ≥ 4 units (postoperative). The results were similar in the control group.

CONCLUSIONS

These scores could be useful to identify patients at risk for NOMI and promote a rapid diagnosis and therapy.

Feeding the Postoperative Patient on Vasopressor Support: Feeding and Pressor Support

Initiating enteral nutrition in the postoperative patient can be challenging. Postoperative ileus and bowel edema, bowel anastomosis, and intra-abdominal pathology contribute to the reluctance and inability to achieve adequate nutrition in this patient population. The addition of vasopressors confounds the difficulties. Clinical data are sparse but suggest that most postoperative patients requiring vasopressor therapy can be safely initiated and advanced on enteral nutrition. Consideration of the vasopressor agent being utilized and its dose is imperative, as are individual patient characteristics. Temporal changes in the dosage should be closely monitored, as increasing doses may reflect worsening clinical status that can be due to intestinal ischemia. Well-designed prospective trials are clearly necessary to address this controversial topic.