Analysis of the evidence for the lower limit of systolic and mean arterial pressure in children

Objective: Systolic blood pressure (SBP) and mean arterial pressure (MAP) are essential evaluation elements in ill children, but there is wide variation among different sources defining systolic hypotension in children, and there are no normal reference values for MAP. Our goal was to calculate the 5th percentile SBP and MAP values in children from recently updated data published by the task force working group of the National High Blood Pressure Education Program and compare these values with the lowest limit of acceptable SBP and MAP defined by different sources. Design: Mathematical analysis of clinical database. Methods: The 50th and 95th percentile SBP values from task force data were used to derive the 5th percentile value for children from 1 to 17 yrs of age stratified by height percentiles. MAP values were calculated using a standard mathematical formula. Calculated SBP values were compared with systolic hypotension definitions from other sources. Linear regression analysis was applied to create simple formulas to estimate 5th percentile SBP and 5th and 50th percentile MAP for different age groups at the 50th height percentile. Results: A 9–21% range in both SBP and MAP values was noted for different height percentiles in the same age groups. The 5th percentile SBP values used to define hypotension by different sources are higher than our calculated values in children but are lower than our calculated values in adolescents. Clinical formulas for calculation of SBP and MAP (mm Hg) in normal children are as follows: SBP (5th percentile at 50th height percentile) = 2 × age in years + 65, MAP (5th percentile at 50th height percentile) = 1.5 × age in years + 40, and MAP (50th percentile at 50th height percentile) = 1.5 × age in years + 55. Conclusion: We developed new estimates for values of 5th percentile SBP and created a table of normal MAP values for reference. SBP is significantly affected by height, which has not been considered previously. Although the estimated lower limits of SBP are lower than currently used to define hypotension, these values are derived from normal healthy children and are likely not appropriate for critically ill children. Our data suggest that the current values for hypotension are not evidence-based and may need to be adjusted for patient height and, most important, for clinical condition. Specifically, we suggest that the definition of hypotension derived from normal children should not be used to define the SBP goal; a higher target SBP is likely appropriate in many critically ill and injured children. Further studies are needed to evaluate the appropriate threshold values of SBP for determining hypotension.

[1]  M. C. Rogers,et al.  Handbook of Pediatric Intensive Care , 1989 .

[2]  C. Lenfant,et al.  National High Blood Pressure Education Program. , 1986, Journal of the American Optometric Association.

[3]  H. Versmold,et al.  Aortic blood pressure during the first 12 hours of life in infants with birth weight 610 to 4,220 grams. , 1981, Pediatrics.

[4]  A. Hyslop.  Early reversal of pediatric-neonatal septic shock by community physicians is associated with improved outcome. , 2004, Pediatrics.

[5]  J. Carcillo,et al.  Pediatric considerations , 2004, Critical care medicine.

[6]  C. Paidas,et al.  Predictors of outcome in severely head-injured children , 2001, Critical care medicine.

[7]  H. Levin,et al.  Severe head injury in children: experience of the Traumatic Coma Data Bank. , 1992 .

[8]  H. Winn,et al.  Blood pressure and outcome after severe pediatric traumatic brain injury. , 2003, The Journal of trauma.

[9]  F. Pigula,et al.  The effect of hypotension and hypoxia on children with severe head injuries. , 1993, Journal of pediatric surgery.

[10]  M. Schreiner.  TEXTBOOK OF PEDIATRIC INTENSIVE CARE , 1988 .

[11]  Stephen M Cohn,et al.  Predictors of Mortality in Trauma Patients , 2004, The American surgeon.

[12]  R. Dellinger,et al.  Cardiovascular management of septic shock. , 2003, Critical care medicine.

[13]  F. Rivara,et al.  Predictors of survival and severity of disability after severe brain injury in children. , 1992, Neurosurgery.

[14]  B. Rosner,et al.  The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents , 2004 .

[15]  A. Greenough,et al.  Effect of gender on blood pressure levels of very low birthweight infants in the first 48 hours of life. , 1993, Early human development.

[16]  Alain Martinot,et al.  Validation of the paediatric logistic organ dysfunction (PELOD) score: prospective, observational, multicentre study , 2003, The Lancet.

[17]  C. Ince,et al.  Microcirculatory oxygenation and shunting in sepsis and shock. , 1999, Critical care medicine.

[18]  J B Stokes,et al.  The national high blood pressure education program. , 1974, Journal of the American Pharmaceutical Association.

[19]  Isabel Rey Madeira,et al.  The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. , 2004, Pediatrics.

[20]  Alan E Jones,et al.  SEVERITY OF EMERGENCY DEPARTMENT HYPOTENSION PREDICTS ADVERSE HOSPITAL OUTCOME , 2004, Shock.

[21]  M. Klauber,et al.  Outcome from head injury related to patient's age. A longitudinal prospective study of adult and pediatric head injury. , 1988, Journal of Neurosurgery.

[22]  E. Ivers,et al.  Early Goal-Directed Therapy in the Treatment of Severe Sepsis and Septic Shock , 2001 .

[23]  A. Randolph,et al.  International pediatric sepsis consensus conference: Definitions for sepsis and organ dysfunction in pediatrics* , 2005, Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.

[24]  E. Rackow,et al.  Effects of perfusion pressure on tissue perfusion in septic shock , 2000, Critical care medicine.

[25]  B. Cooper,et al.  Reappraisal of norepinephrine therapy in human septic shock. , 1990, Critical care medicine.

[26]  K. Mackway-Jones,et al.  Systolic hypertension and the response to blunt trauma in infants and children. , 2002, Resuscitation.

[27]  C. Robertson.  Management of Cerebral Perfusion Pressure after Traumatic Brain Injury , 2001 .

[28]  A. Wechsler-Fördös,et al.  The effects of norepinephrine on hemodynamics and renal function in severe septic shock states , 2005, Intensive Care Medicine.

[29]  R. Willoughby,et al.  Textbook of Pediatric Intensive Care , 1996 .

[30]  R. Cooke,et al.  Blood pressure and cerebral haemorrhage and ischaemia in very low birthweight infants. , 1989, Early human development.

[31]  S. Wedel,et al.  Isolated prehospital hypotension after traumatic injuries: a predictor of mortality? , 2003, The Journal of emergency medicine.

[32]  M. Horan.  Report of the Second Task Force on Blood Pressure Control in Children--1987. Task Force on Blood Pressure Control in Children. National Heart, Lung, and Blood Institute, Bethesda, Maryland. , 1987, Pediatrics.

[33]  T. Pittman,et al.  Early hypotension worsens neurological outcome in pediatric patients with moderately severe head trauma. , 1998, Journal of pediatric surgery.

[34]  J. Carcillo,et al.  Clinical practice parameters for hemodynamic support of pediatric and neonatal patients in septic shock* , 2002, Critical care medicine.