New automated system better for controlling maternal blood pressure during caesarean delivery
A double intravenous vasopressor automated (DIVA) system appears to be more effective than manual vasopressor bolus administration (MVB) at controlling maternal blood pressure (BP) following spinal anaesthesia during caesarean delivery, a new Singapore study has shown.
“[W]hen compared with the MVB group, we have shown that the DIVA system with continuous noninvasive monitoring is able to achieve a lower incidence of maternal hypotension, less hypotensive readings and less wobble, without higher vasopressor consumption,” the researchers said.
The researchers performed the randomized, double-blind controlled trial on 230 mothers undergoing elective caesarean under spinal anaesthesia at the KK Women’s and Children’s Hospital in Singapore. The participants were randomly designated to receive either DIVA (n=117; mean age 32.8±4.7 years) or MVB (n=113; mean age 32.9±4.8 years).
Compared with MVB, DIVA appeared to yield significantly better haemodynamic control. For instance, the proportion of readings with hypertension (12.2 percent vs 17.2 percent; p<0.0001) and hypotension (4.7 percent vs 7.8 percent; p<0.0001) was significantly lower in the DIVA than in the MVB group. [Eur J Anaesthesiol 2018;doi:10.1097/EJA.0000000000000779]
Similarly, the proportion of patients with hypotension (39.3 percent vs 57.5 percent; p=0.008) was significantly lower in the DIVA group, while the number of mothers with hypertension (80.3 percent vs 87.6 percent; p=0.153) was nominally lower. There was no significant difference in the total volume of fluid delivered between the DIVA and MVB groups (721.2±270.2 vs 708.4±269.4 mL; p=0.720).
In terms of system performance, DIVA showed significantly lower wobble than MVB (6.7 percent vs 8.2 percent; p=0.012). There was no significant advantage of one method over the other in terms of other performance parameters and of maximum (p=0.139) and minimum (p=0.354) systolic (S)BP.
“We found that the updated DIVA system using the Nexfin with a two-step algorithm achieved significantly less number of hypotensive readings, lower incidence of maternal hypotension and lower wobble than the MVB group,” said researchers.
According to the researchers, they refined the algorithm of DIVA to allow for smaller vasopressor doses administered when the machine detects that SBP dropped to 90–100 percent of baseline. This prevents further reductions in SBP without causing reactive hypertension.
“We have demonstrated that that our improved double-vasopressor system with the built-in noninvasive continuous haemodynamic monitoring device Nexfin was able to maintain maternal SBP close to the baseline,” they added.
The research team also evaluated maternal and neonatal outcomes affected by the treatment. They found that fewer mothers in the DIVA vs MVB group experienced nausea (11 vs 16), although the difference was not statistically significant. Other maternal outcomes, such as bradycardia and vomiting, were statistically comparable between the patient groups.
The two treatment methods also resulted in statistically similar neonatal outcomes, including umbilical cord pH, lactate levels and Apgar scores.