Percentage of cases with systolic blood pressure <90mmHg for less than or equal to 5 minutes during the time from spinal placement to delivery. 

Neuraxial anesthesia is widely used for cesarean delivery and is associated with lower mortality and morbidity when compared to general anesthesia.^5,8,10 Though overall morbidity is lower, neuraxial anesthesia can lead to maternal hypotension which has been cited as a common maternal complication during cesarean delivery.^5-11 Hypotension can cause fetal acidosis and maternal nausea and vomiting.^2,10,12 Prolonged hypotension can result in organ ischemia, uteroplacental hypoperfusion, loss of consciousness, and cardiovascular collapse.^2,8 Techniques currently used to prevent hypotension related to spinal placement include intravenous fluid prehydration, vasopressor infusions, and less commonly physical methods such as leg elevation and compression stockings.^2,5,8,10,11 

In a Cochrane review of 126 studies including 9565 patients, 94 of the studies defined hypotension as a maternal systolic blood pressure below 80% of baseline recording, absolute value of less than 90 or 100 mmHg, or some combination thereof.² Patients experiencing severe preeclampsia may be at lower risk of hypotension (but higher risk of other complications)  as compared to healthy parturients.¹ Nonetheless, hypotension and low placental perfusion remain a risk for the preeclamptic patient undergoing neuraxial anesthesia, necessitating the same level of vigilance as for non pre-eclamptic patients.^3,7

Spinal placement to neonate delivery

All cesarean deliveries (as determined using the MPOG Obstetric Anesthesia Type phenotype) with neuraxial anesthesia only (as determined by the Anesthesia Technique-Neuraxial MPOG Phenotype

• Cesarean delivery patients undergoing general anesthesia (as determined using the MPOG Anesthesia Technique-General MPOG phenotype)
• Patients undergoing cesarean section with hysterectomy (as determined by the MPOG Obstetric Anesthesia Type Phenotype)
• Emergency cesarean delivery with diagnosis of placental abruption (ICD-10: O45*)
• Rupture of uterus (spontaneous) before onset of labor (ICD-10: O71.0)
• Newborn affected by intrauterine blood loss from ruptured cord (ICD-10: P50.1)
• Abnormal uterine or vaginal bleeding, unspecified (ICD-10: N93.9)
• Placenta previa with hemorrhage, third trimester (ICD-10: O44.13)
• Hemorrhage from placenta previa, antepartum condition or complication (ICD-10: 641.13)
• Hemorrhage from placenta previa, delivered, with or without mention of antepartum condition (ICD-10: 641.11)
• ICD-10 Codes associated with the case and documented from 7 days before to 30 days after the case are considered

SBP <90mmHg for less than or equal to 5 minutes during the time period of spinal placement to delivery

Measure Start Time: 

1. For scheduled cesarean delivery cases (as determined by the Obstetric Anesthesia Type phenotype): Will use Neuraxial Start Time (phenotype)
   1. If Neuraxial Start Time is earlier than ‘Anesthesia Start’, will use ‘Anesthesia Start’
2. For labor epidural cases that are converted to cesarean delivery and are documented as a single case (as determined by the Obstetric Anesthesia Type phenotype): Will use the Cesarean Delivery Start Time for Conversion Cases (phenotype)
3. For labor epidural cases that are converted to cesarean delivery and documented as two separate cases (as determined by the Obstetric Anesthesia Type phenotype): Will use the Cesarean Delivery Start Time for Conversion Cases (phenotype)

Measure End Time (limited to concepts between ‘anesthesia start’ and ‘anesthesia end’): 

1. Delivery of Neonate 2 (50189), if not available 
2. Delivery of Neonate (50358), if not available, 
3. Oxytocin (10343) Administration Start Time (bolus or infusion), if not available,
4. Obstetrics - Uterine Incision (50357), if not available,
5. AACD Anesthesia End Date/Time (50009)

• Cases where the ‘Measure End Time’ precedes ‘Measure Start Time’ will be excluded and marked 'invalid'
• Multiple blood pressures: Instances where there are two blood pressure monitoring methods, the higher MAP will be used to determine measure compliance.
• Artifact: Artifact readings will be identified and removed from final measurement calculation. Artifact processing: if systolic and diastolic blood pressures are present, the values must be at least 5 mmHg apart; otherwise the values will be excluded. MAP values less than 10 are excluded.
• Each incidence of hypotension will count for a max of 5 minutes or until ‘Measure End’ (whichever is sooner)  if there is a gap in blood pressure measurement
• Use Oxytocin administration start time as determined by oxytocin documented on the case within the measure time period.

N/a

Not applicable- departmental measure only

1. Aya AGM, Mangin R, Vialles N, Ferrer J-M, Robert C, Ripart J, La Coussaye J-E de: Patients with severe preeclampsia experience less hypotension during spinal anesthesia for elective cesarean delivery than healthy parturients: a prospective cohort comparison. Anesth Analg 2003; 97:867–72
2. Chooi C, Cox JJ, Lumb RS, Middleton P, Chemali M, Emmett RS, Simmons SW, Cyna AM: Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst Rev 2017; 8:CD002251
3. Dyer RA, Piercy JL, Reed AR, Lombard CJ, Schoeman LK, James MF: Hemodynamic changes associated with spinal anesthesia for cesarean delivery in severe preeclampsia. Anesthesiology 2008; 108:802–11
4. Fassoulaki A, Staikou C, Melemeni A, Kottis G, Petropoulos G: Anaesthesia preference, neuraxial vs general, and outcome after caesarean section. J Obstet Gynaecol 2010; 30:818–21
5. Hasanin AM, Amin SM, Agiza NA, Elsayed MK, Refaat S, Hussein HA, Rouk TI, Alrahmany M, Elsayad ME, Elshafaei KA, Refaie A: Norepinephrine Infusion for Preventing Postspinal Anesthesia Hypotension during Cesarean Delivery: A Randomized Dose-finding Trial. Anesthesiology 2019; 130:55–62
6. Hawkins JL, Koonin LM, Palmer SK, Gibbs CP: Anesthesia-related deaths during obstetric delivery in the United States, 1979-1990. Anesthesiology 1997; 86:277–84
7. Karinen J, Räsänen J, Alahuhta S, Jouppila R, Jouppila P: Maternal and uteroplacental haemodynamic state in pre-eclamptic patients during spinal anaesthesia for Caesarean section. Br J Anaesth 1996; 76:616–20
8. Macarthur A, Riley ET: Obstetric anesthesia controversies: vasopressor choice for postspinal hypotension during cesarean delivery. Int Anesthesiol Clin 2007; 45:115–32
9. Mercier FJ, Augè M, Hoffmann C, Fischer C, Le Gouez A: Maternal hypotension during spinal anesthesia for caesarean delivery. Minerva Anestesiol 2013; 79:62–73
10. McDonnell NJ, Paech MJ, Muchatuta NA, Hillyard S, Nathan EA: A randomised double-blind trial of phenylephrine and metaraminol infusions for prevention of hypotension during spinal and combined spinal-epidural anaesthesia for elective caesarean section. Anaesthesia 2017; 72:609–17
11. Ngan Kee WD, Khaw KS, Ng FF: Prevention of Hypotension during Spinal Anesthesia for Cesarean DeliveryAn Effective Technique Using Combination Phenylephrine Infusion and Crystalloid Cohydration. Anesthesiology 2005; 103:744–50
12. Reynolds F, Seed PT: Anaesthesia for Caesarean section and neonatal acid-base status: a meta-analysis. Anaesthesia 2005; 60:636–53