[Characteristics of changes in non-invasive hemodynamic parameters in neonates with septic shock]

To observe the characteristics of changes in non-invasive hemodynamic parameters in neonates with septic shock so as to provide clinical reference for diagnosis and treatment.

A observational study was conducted. The neonates with sepsis complicated with septic shock or not admitted to neonatal intensive care unit (NICU) of the First Affiliated Hospital of Shantou University Medical College were enrolled as the study subjects, who were divided into preterm infant (< 37 weeks) and full-term infant (≥ 37 weeks) according to the gestational age. Healthy full-term infants and hemodynamically stable preterm infants transferring to NICU after birth were enrolled as controls. Electronic cardiometry (EC) was used to measure hemodynamic parameters, including heart rate (HR), mean arterial pressure (MAP), stroke volume (SV), stroke volume index (SVI), cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR) and systemic vascular resistance index (SVRI), before treatment in the septic shock group, at the time of diagnosis of sepsis in the sepsis without shock group, and before the discharge from the obstetric department or on the day of transferring to NICU in the control group.

Finally, 113 neonates with complete data and parental consent for non-invasive hemodynamic monitoring were enrolled, including 32 cases in the septic shock group, 25 cases in the sepsis without shock group and 56 cases in the control group. In the septic shock group, there were 17 cases at the compensated stage and 15 cases at the decompensated stage. There were 21 full-term infants (20 cured or improved and 1 died) and 11 premature infants (7 cured or improved and 4 died), with the mortality of 15.62% (5/32). There were 18 full-term infants and 7 premature infants in the sepsis without shock group and all cured or improved without death. The control group included 28 full-term infants and 28 premature infants transferring to NICU after birth. Non-invasive hemodynamic parameter analysis showed that SV, SVI, CO and CI of full-term infants in the septic shock group were significantly lower than those in the sepsis without shock group and control group [SV (mL): 3.52±0.99 vs. 5.79±1.32, 5.22±1.02, SVI (mL/m²): 16.80 (15.05, 19.65) vs. 27.00 (22.00, 32.00), 27.00 (23.00, 29.75), CO (L/min): 0.52±0.17 vs. 0.80±0.14, 0.72±0.12, CI (mL×s^-1×m^-2): 40.00 (36.67, 49.18) vs. 62.51 (56.34, 70.85), 60.01 (53.34, 69.68), all P < 0.05], while SVR and SVRI were significantly higher than those in the sepsis without shock group and control group [SVR (kPa×s×L^-1): 773.46±291.96 vs. 524.17±84.76, 549.38±72.36, SVRI (kPa×s×L^-1×m^-2): 149.27±51.76 vs. 108.12±12.66, 107.81±11.87, all P < 0.05]. MAP, SV, SVI, CO and CI of preterm infants in the septic shock group were significantly lower than those in the control group [MAP (mmHg, 1 mmHg ≈ 0.133 kPa): 38.55±10.48 vs. 47.46±2.85, SV (mL): 2.45 (1.36, 3.58) vs. 3.96 (3.56, 4.49), SVI (mL/m²): 17.60 (14.20, 25.00) vs. 25.50 (24.00, 29.00), CO (L/min): 0.32 (0.24, 0.63) vs. 0.56 (0.49, 0.63), CI (mL×s^-1×m^-2): 40.01 (33.34, 53.34) vs. 61.68 (56.68, 63.35), all P < 0.05], while SVR and SVRI were similar to the control group [SVR (kPa×s×L^-1): 1 082.88±689.39 vs. 656.63±118.83, SVRI (kPa×s×L^-1×m^-2): 126.00±61.50 vs. 102.37±11.68, both P > 0.05]. Further analysis showed that SV, SVI and CI of neonates at the compensation stage in the septic shock group were significantly lower than those in the control group [SV (mL): 3.60±1.29 vs. 4.73±1.15, SVI (mL/m²): 19.20±8.33 vs. 26.34±3.91, CI (mL×s^-1×m^-2): 46.51±20.34 vs. 61.01±7.67, all P < 0.05], while MAP, SVR and SVRI were significantly higher than those in the control group [MAP (mmHg): 52.06±8.61 vs. 48.54±3.21, SVR (kPa×s×L^-1): 874.95±318.70 vs. 603.01±111.49, SVRI (kPa×s×L^-1×m^-2): 165.07±54.90 vs. 105.09±11.99, all P < 0.05]; MAP, SV, SVI, CO and CI of neonates at the decompensated stage in the septic shock group were significantly lower than those in the control group [MAP (mmHg): 35.13±6.08 vs. 48.54±3.21, SV (mL): 2.89±1.17 vs. 4.73±1.15, SVI (mL/m²): 18.50±4.99 vs. 26.34±3.91, CO (L/min): 0.41±0.19 vs. 0.65±0.15, CI (mL×s^-1×m^-2): 43.34±14.17 vs. 61.01±7.67, all P < 0.05], while SVR and SVRI were similar to the control group [SVR (kPa×s×L^-1): 885.49±628.04 vs. 603.01±111.49, SVRI (kPa×s×L^-1×m^-2): 114.29±43.54 vs. 105.09±11.99, both P > 0.05].

Full-term infant with septic shock exhibit a low cardiac output, high vascular resistance hemodynamic pattern, while preterm infant with septic shock show low cardiac output and normal vascular resistance. At the compensated stage the hemodynamic change is low output and high resistance type, while at the decompensated stage it is low output and normal resistance type. Non-invasive hemodynamic monitoring can assist in the identification of neonatal septic shock and provide basis for clinical diagnosis and treatment.