Acute Systemic Complications in the Preterm Fetus After Asphyxia: Role of Cardiovascular and Blood Flow Responses

Abstract

SUMMARY1. Poor perfusion of the kidneys and gut, and associated functional impairment, are major problems in the first days of life in very preterm infants. These complications can be associated with a substantial mortality and further problems such as reduced kidney growth and chronic renal problems in later childhood.2. There is very little information, and consequently considerable debate, about how or even whether to improve perfusion of the vital organs of this most vulnerable group of babies. Current treatments simply do not consistently improve babies' perfusion generally or kidney and gut perfusion and function in particular.3. In this review we critically examine clinical and experimental evidence that suggests that exposure to low oxygen levels before and during birth may be a significant contributor to impaired systemic perfusion, and highlight areas requiring further research.4. This knowledge is essential to develop and refine ways of improving perfusion of the kidneys and other vital organs in premature babies.

Intestinal Hemodynamic Effects of Milrinone in Asphyxiated Newborn Pigs After Reoxygenation With 100% Oxygen

“…The dose-dependent effect of milrinone on cardiac output in this study has been recently reported (18). The relationship between blood pressure, cardiac output, and intestinal perfusion during H-R is still not well defined (7,8,23,24). In our study, milrinone's ability to support the intestinal perfusion coincided with an increased cardiac output without altering MAP.…”

“…However, other hypoxic animal models demonstrate persistent intestinal hypoperfusion associated with increased vascular resistance despite reoxygenation. Restoration of gut perfusion after hypoxia occurred only when SMA vascular resistance decreased and not when blood pressure increased (7,8).…”

Intestinal Hemodynamic Effects of Milrinone in Asphyxiated Newborn Pigs After Reoxygenation With 100% Oxygen

“…The dose-dependent effect of milrinone on cardiac output in this study has been recently reported (18). The relationship between blood pressure, cardiac output, and intestinal perfusion during H-R is still not well defined (7,8,23,24). In our study, milrinone's ability to support the intestinal perfusion coincided with an increased cardiac output without altering MAP.…”

“…However, other hypoxic animal models demonstrate persistent intestinal hypoperfusion associated with increased vascular resistance despite reoxygenation. Restoration of gut perfusion after hypoxia occurred only when SMA vascular resistance decreased and not when blood pressure increased (7,8).…”

Hemodynamic effects of high‐frequency oscillatory ventilation in preterm neonates with respiratory distress syndrome

“…Changes in organ blood flow and perfusion are of great importance in premature neonates as they are related to IVH, renal injury, and necrotizing enterocolitis. 37,38 Therefore, early detection of decreased organ perfusion, if any, with the use of HFOV is of invaluable role to prevent these complications.…”

“…Moreover, we found that pre‐HFOV RI values of the cerebral arteries, renal arteries, SMA, and CA were significantly higher in neonates with hs‐PDA than in those with closed or small PDA that indicated low blood flow in these patients, however post‐HFOV RI values in these arteries decreased significantly in neonates with hs‐PDA. Changes in organ blood flow and perfusion are of great importance in premature neonates as they are related to IVH, renal injury, and necrotizing enterocolitis 37,38 . Therefore, early detection of decreased organ perfusion, if any, with the use of HFOV is of invaluable role to prevent these complications.…”

Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: clinical implications of a large Dutch cohort study

“…To our knowledge, this has not been described before. Histopathological changes that occur in NEC, such as mucosa oedema, haemorrhage and necrosis, are most often found in the watershed areas between the superior and inferior mesenteric artery, at the level of ileum and proximal colon, which strongly suggests ischaemic injury 28 . It is tempting to speculate that in MC twin pregnancies, this ischaemic injury is a consequence of episodes of hypovolaemia that may occur due to imbalanced vascular anastomoses in the placenta.…”

Intestinal Hemodynamic Effects of Milrinone in Asphyxiated Newborn Pigs After Reoxygenation With 100% Oxygen

“…The dose-dependent effect of milrinone on cardiac output in this study has been recently reported (18). The relationship between blood pressure, cardiac output, and intestinal perfusion during H-R is still not well defined (7,8,23,24). In our study, milrinone's ability to support the intestinal perfusion coincided with an increased cardiac output without altering MAP.…”

“…However, other hypoxic animal models demonstrate persistent intestinal hypoperfusion associated with increased vascular resistance despite reoxygenation. Restoration of gut perfusion after hypoxia occurred only when SMA vascular resistance decreased and not when blood pressure increased (7,8).…”

Hemodynamic effects of high‐frequency oscillatory ventilation in preterm neonates with respiratory distress syndrome

“…Changes in organ blood flow and perfusion are of great importance in premature neonates as they are related to IVH, renal injury, and necrotizing enterocolitis. 37,38 Therefore, early detection of decreased organ perfusion, if any, with the use of HFOV is of invaluable role to prevent these complications.…”

“…Moreover, we found that pre‐HFOV RI values of the cerebral arteries, renal arteries, SMA, and CA were significantly higher in neonates with hs‐PDA than in those with closed or small PDA that indicated low blood flow in these patients, however post‐HFOV RI values in these arteries decreased significantly in neonates with hs‐PDA. Changes in organ blood flow and perfusion are of great importance in premature neonates as they are related to IVH, renal injury, and necrotizing enterocolitis 37,38 . Therefore, early detection of decreased organ perfusion, if any, with the use of HFOV is of invaluable role to prevent these complications.…”

Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: clinical implications of a large Dutch cohort study

“…To our knowledge, this has not been described before. Histopathological changes that occur in NEC, such as mucosa oedema, haemorrhage and necrosis, are most often found in the watershed areas between the superior and inferior mesenteric artery, at the level of ileum and proximal colon, which strongly suggests ischaemic injury 28 . It is tempting to speculate that in MC twin pregnancies, this ischaemic injury is a consequence of episodes of hypovolaemia that may occur due to imbalanced vascular anastomoses in the placenta.…”

Intestinal Hemodynamic Effects of Milrinone in Asphyxiated Newborn Pigs After Reoxygenation With 100% Oxygen

“…The dose-dependent effect of milrinone on cardiac output in this study has been recently reported (18). The relationship between blood pressure, cardiac output, and intestinal perfusion during H-R is still not well defined (7,8,23,24). In our study, milrinone's ability to support the intestinal perfusion coincided with an increased cardiac output without altering MAP.…”

“…However, other hypoxic animal models demonstrate persistent intestinal hypoperfusion associated with increased vascular resistance despite reoxygenation. Restoration of gut perfusion after hypoxia occurred only when SMA vascular resistance decreased and not when blood pressure increased (7,8).…”

Hemodynamic effects of high‐frequency oscillatory ventilation in preterm neonates with respiratory distress syndrome

“…Changes in organ blood flow and perfusion are of great importance in premature neonates as they are related to IVH, renal injury, and necrotizing enterocolitis. 37,38 Therefore, early detection of decreased organ perfusion, if any, with the use of HFOV is of invaluable role to prevent these complications.…”

“…Moreover, we found that pre‐HFOV RI values of the cerebral arteries, renal arteries, SMA, and CA were significantly higher in neonates with hs‐PDA than in those with closed or small PDA that indicated low blood flow in these patients, however post‐HFOV RI values in these arteries decreased significantly in neonates with hs‐PDA. Changes in organ blood flow and perfusion are of great importance in premature neonates as they are related to IVH, renal injury, and necrotizing enterocolitis 37,38 . Therefore, early detection of decreased organ perfusion, if any, with the use of HFOV is of invaluable role to prevent these complications.…”

Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: clinical implications of a large Dutch cohort study

“…To our knowledge, this has not been described before. Histopathological changes that occur in NEC, such as mucosa oedema, haemorrhage and necrosis, are most often found in the watershed areas between the superior and inferior mesenteric artery, at the level of ileum and proximal colon, which strongly suggests ischaemic injury 28 . It is tempting to speculate that in MC twin pregnancies, this ischaemic injury is a consequence of episodes of hypovolaemia that may occur due to imbalanced vascular anastomoses in the placenta.…”