Q: Following cesarean delivery, what is the optimal oxytocin infusion duration to prevent postpartum bleeding?

CASE: DISCONTINUED OXYTOCIN LEADS TO POSTPARTUM HEMORRHAGE
You have just completed a repeat cesarean delivery for a 41-year-old woman, now G2P2. You order an infusion of oxytocin, 20 U in 1 L lactated Ringer’s solution, to run at a rate of 125 mL/hr for 8 hours. Without informing you, the recovery room nurse discontinues the bag with the oxytocin solution and starts an infusion of lactated Ringer’s solution without oxytocin.

One hour later, you are called to the recovery room because your patient is having a postpartum hemorrhage (PPH). Physical examination shows that the uterus is boggy and above the level of the umbilicus. On ­bedside ­ultrasonography, the uterine cavity is demonstrated to contain minimal blood, and Doppler sonography does not demonstrate any vascular tissue within the uterine cavity. You diagnose uterine atony and initiate treatment. You massage the uterus, rapidly infuse 1 L crystalloid solution, place misoprostol 800 µg in the rectum, and reinitiate the oxytocin infusion. The uterine bleeding slows and then stops.

The following morning, the patient’s hematocrit has decreased from a preoperative value of 37% to 21%.  

Could this case of PPH have been prevented?

Cesarean delivery is one of the most commonly performed major operations in developed countries. More than 1,250,000 cesarean deliveries are performed annually in the United States. In 2012, there were 3,952,937 births and a cesarean delivery rate of 32.8%.¹ It is an important goal of obstetric care providers to continuously improve our approach to cesarean delivery in order to minimize the surgical risks of this procedure. Evidence-based, standardized protocols for cesarean delivery are critical to ensuring high- reliability surgical outcomes.

A key gap in cesarean delivery protocols is the lack of a nationwide, standardized approach to reducing the risk of postoperative bleeding by maintaining a continuous infusion of oxytocin in the hours immediately following cesarean delivery. 

OXYTOCIN: A CRITICAL INTERVENTION TO PREVENT PPH
More than half of all maternal deaths occur in the 24 hours following delivery, with the most common cause being PPH.² In addition to death, serious complications of PPH include coagulopathy, shock, emergency hysterectomy, transfusion complications, respiratory distress, and pituitary necrosis. Most cases of PPH that occur within 24 hours of delivery are caused by uterine atony.³ Other causes include retained products of conception, placenta accreta, infection, coagulation defects, and amniotic fluid embolism.

Administering a uterotonic such as oxytocin at the time of delivery reduces the risk of PPH by approximately 66% and the risk of maternal blood transfusion by about 65%.⁴ In order to prevent uterine atony and PPH, oxytocin should be routinely administered following birth of the baby or after delivery of the placenta. Appropriate doses following vaginal delivery are oxytocin 10 U administered intramuscularly or 10 U administered as a slow intravenous (IV) infusion.⁵ The onset of action of oxytocin is approximately 2 to 5 minutes after an intramuscular dose and 1 minute after an IV dose.⁶ 

Related article: Routine use of oxytocin at birth: just the right amount to prevent postpartum hemorrhage  Robert L. Barbieri, MD (Editorial, July 2012)

OXYTOCIN AND CESAREAN DELIVERY
Many clinical trials have reported that during a cesarean delivery, the routine administration of a uterotonic agent following birth of the baby reduces the risk of uterine atony and excessive bleeding. Three uterotonics: oxytocin, misoprostol, and carbetocin (a long-acting oxytocin analogue, see SIDEBAR), have been reported to reduce the risk of excessive bleeding during cesarean delivery.⁷ Oxytocin is the uterotonic most commonly used during cesarean delivery in developed countries. 

Related article: A new (to the US) first-line agent for heavy menstrual bleeding Robert L. Barbieri, MD (Editorial, October 2010)

In the United States, there is no standardized oxytocin regimen for prevention of uterine atony and hemorrhage at cesarean delivery. The most common regimen is to add 10–40 U of oxytocin in 1 L crystalloid solution and initiate the oxytocin infusion following delivery of the baby. Initially, the infusion is run at a rapid rate. Once the obstetrician reports that there is adequate uterine tone, the infusion rate is slowed to one that maintains uterine tone.

Some clinicians administer a single bolus of oxytocin following birth of the baby. However, a bolus of oxytocin commonly causes hypotension and, less commonly, ST segment changes on the electrocardiogram (EKG) suggestive of cardiac ischemia.^8–10Many experts recommend against administering one large bolus of oxytocin over a short period of time and favor a continuous infusion.

At cesarean delivery, the minimum infusion rate of oxytocin that has been reported to avoid most cases of uterine atony, as reported by the obstetrician immediately following delivery, is approximately oxytocin 0.3 U/min.¹¹ Oxytocin infusion rates of 0.2 U/min and 0.1 U/min were associated with uterine atony rates of 21% and 40%, respectively. An infusion rate of oxytocin 0.3 U/min can be achieved by the administration of 20 U of oxytocin in 1 L crystalloid solution at a rate of 15 mL/min until uterine tone is achieved. The oxytocin dose then can be titrated to maintain adequate uterine tone. Following completion of surgery, uterine tone can be maintained with a low-dose continuous infusion of oxytocin.  

4- TO 8-HOUR OXYTOCIN RULE
A key gap in our cesarean delivery protocols is a standardized recommendation concerning the duration of the oxytocin infusion following cesarean delivery. To my knowledge, no national organization has made a firm recommendation concerning the duration of oxytocin infusion following cesarean delivery.

One recent clinical trial studied PPH following cesarean delivery utilizing two oxytocin regimens: a bolus of oxytocin following delivery of the baby versus a bolus of oxytocin followed by a 4-hour IV infusion of oxytocin.¹² In this trial, 2,058 women undergoing a scheduled cesarean delivery with a singleton pregnancy were randomly assigned to an oxytocin bolus alone, oxytocin 5 U administered intravenously over 1 minute, or an oxytocin bolus plus a 4-hour oxytocin infusion at a rate of 10 U/hr. The 4-hour postoperative oxytocin infusion was formulated by adding 40 U of oxytocin to 500 mL saline and infusing the solution at 125 mL/hr, equivalent to 0.167 U of oxytocin per minute. In this trial, 65% of the women were undergoing a repeat cesarean delivery and 35% were undergoing a primary cesarean delivery.

The authors reported that women who received the oxytocin bolus alone were significantly more likely to be diagnosed with uterine atony requiring additional uterotonic treatment than women who received both the bolus and the 4-hour postoperative infusion (18.4% versus 12.2%, respectively; P <.001). There was no difference in the rate of PPH between the two groups.

The rate of PPH was 16% in women receiving an oxytocin bolus alone and 15.7% in women receiving both an oxytocin bolus and the continuous oxytocin infusion. However, among less experienced surgeons, the rate of PPH was significantly greater in the group that received the oxytocin bolus alone compared with the women receiving the bolus and continuous infusion (22.2% versus 17.3%, respectively). The authors concluded that obstetricians should consider using a 4-hour infusion of oxytocin following cesarean delivery to reduce the risk of uterine atony.

In a recent evidence-based review of optimal interventions in cesarean delivery, the authors recommended an IV infusion of 10 to 40 U of oxytocin administered over 4 to 8 hours after cesarean delivery.7 Following cesarean, an IV infusion of crystalloid solution is typically maintained for at least 4 to 8 hours. Consequently, adding oxytocin (which costs approximately $1 for 10 units) to the crystalloid infusion does not add substantially to the cost of the patient’s postoperative care and may reduce the risk of uterine atony and PPH.

Related article: Act fast when confronted by a coagulopathy postpartum Robert L. Barbieri, MD (Editorial, March 2012)

My bottom-line recommendation. In the United States, we should adopt a policy of maintaining a continuous infusion of oxytocin for 4 to 8 hours following a cesarean delivery. Following a 4- to 8-hour rule will decrease the rate of uterine atony and excessive bleeding, thereby improving the safety of our cesarean delivery surgery. 

INSTANT POLL
How many hours following cesarean delivery do you think that an oxytocin infusion should be maintained to reduce the risk of uterine atony and postpartum hemorrhage?
If the patient is a Jehovah’s Witness and refuses the transfusion of all blood products, how many hours following cesarean delivery do you think that an oxytocin infusion should be maintained to reduce the risk of uterine atony and postpartum hemorrhage?
Tell us—at [email protected] Please include your name and city and state.

CASE: DISCONTINUED OXYTOCIN LEADS TO POSTPARTUM HEMORRHAGE
You have just completed a repeat cesarean delivery for a 41-year-old woman, now G2P2. You order an infusion of oxytocin, 20 U in 1 L lactated Ringer’s solution, to run at a rate of 125 mL/hr for 8 hours. Without informing you, the recovery room nurse discontinues the bag with the oxytocin solution and starts an infusion of lactated Ringer’s solution without oxytocin.

One hour later, you are called to the recovery room because your patient is having a postpartum hemorrhage (PPH). Physical examination shows that the uterus is boggy and above the level of the umbilicus. On ­bedside ­ultrasonography, the uterine cavity is demonstrated to contain minimal blood, and Doppler sonography does not demonstrate any vascular tissue within the uterine cavity. You diagnose uterine atony and initiate treatment. You massage the uterus, rapidly infuse 1 L crystalloid solution, place misoprostol 800 µg in the rectum, and reinitiate the oxytocin infusion. The uterine bleeding slows and then stops.

The following morning, the patient’s hematocrit has decreased from a preoperative value of 37% to 21%.  

Could this case of PPH have been prevented?

Cesarean delivery is one of the most commonly performed major operations in developed countries. More than 1,250,000 cesarean deliveries are performed annually in the United States. In 2012, there were 3,952,937 births and a cesarean delivery rate of 32.8%.¹ It is an important goal of obstetric care providers to continuously improve our approach to cesarean delivery in order to minimize the surgical risks of this procedure. Evidence-based, standardized protocols for cesarean delivery are critical to ensuring high- reliability surgical outcomes.

A key gap in cesarean delivery protocols is the lack of a nationwide, standardized approach to reducing the risk of postoperative bleeding by maintaining a continuous infusion of oxytocin in the hours immediately following cesarean delivery. 

OXYTOCIN: A CRITICAL INTERVENTION TO PREVENT PPH
More than half of all maternal deaths occur in the 24 hours following delivery, with the most common cause being PPH.² In addition to death, serious complications of PPH include coagulopathy, shock, emergency hysterectomy, transfusion complications, respiratory distress, and pituitary necrosis. Most cases of PPH that occur within 24 hours of delivery are caused by uterine atony.³ Other causes include retained products of conception, placenta accreta, infection, coagulation defects, and amniotic fluid embolism.

Administering a uterotonic such as oxytocin at the time of delivery reduces the risk of PPH by approximately 66% and the risk of maternal blood transfusion by about 65%.⁴ In order to prevent uterine atony and PPH, oxytocin should be routinely administered following birth of the baby or after delivery of the placenta. Appropriate doses following vaginal delivery are oxytocin 10 U administered intramuscularly or 10 U administered as a slow intravenous (IV) infusion.⁵ The onset of action of oxytocin is approximately 2 to 5 minutes after an intramuscular dose and 1 minute after an IV dose.⁶ 

Related article: Routine use of oxytocin at birth: just the right amount to prevent postpartum hemorrhage  Robert L. Barbieri, MD (Editorial, July 2012)

OXYTOCIN AND CESAREAN DELIVERY
Many clinical trials have reported that during a cesarean delivery, the routine administration of a uterotonic agent following birth of the baby reduces the risk of uterine atony and excessive bleeding. Three uterotonics: oxytocin, misoprostol, and carbetocin (a long-acting oxytocin analogue, see SIDEBAR), have been reported to reduce the risk of excessive bleeding during cesarean delivery.⁷ Oxytocin is the uterotonic most commonly used during cesarean delivery in developed countries. 

Related article: A new (to the US) first-line agent for heavy menstrual bleeding Robert L. Barbieri, MD (Editorial, October 2010)

In the United States, there is no standardized oxytocin regimen for prevention of uterine atony and hemorrhage at cesarean delivery. The most common regimen is to add 10–40 U of oxytocin in 1 L crystalloid solution and initiate the oxytocin infusion following delivery of the baby. Initially, the infusion is run at a rapid rate. Once the obstetrician reports that there is adequate uterine tone, the infusion rate is slowed to one that maintains uterine tone.

Some clinicians administer a single bolus of oxytocin following birth of the baby. However, a bolus of oxytocin commonly causes hypotension and, less commonly, ST segment changes on the electrocardiogram (EKG) suggestive of cardiac ischemia.^8–10Many experts recommend against administering one large bolus of oxytocin over a short period of time and favor a continuous infusion.

At cesarean delivery, the minimum infusion rate of oxytocin that has been reported to avoid most cases of uterine atony, as reported by the obstetrician immediately following delivery, is approximately oxytocin 0.3 U/min.¹¹ Oxytocin infusion rates of 0.2 U/min and 0.1 U/min were associated with uterine atony rates of 21% and 40%, respectively. An infusion rate of oxytocin 0.3 U/min can be achieved by the administration of 20 U of oxytocin in 1 L crystalloid solution at a rate of 15 mL/min until uterine tone is achieved. The oxytocin dose then can be titrated to maintain adequate uterine tone. Following completion of surgery, uterine tone can be maintained with a low-dose continuous infusion of oxytocin.  

4- TO 8-HOUR OXYTOCIN RULE
A key gap in our cesarean delivery protocols is a standardized recommendation concerning the duration of the oxytocin infusion following cesarean delivery. To my knowledge, no national organization has made a firm recommendation concerning the duration of oxytocin infusion following cesarean delivery.

One recent clinical trial studied PPH following cesarean delivery utilizing two oxytocin regimens: a bolus of oxytocin following delivery of the baby versus a bolus of oxytocin followed by a 4-hour IV infusion of oxytocin.¹² In this trial, 2,058 women undergoing a scheduled cesarean delivery with a singleton pregnancy were randomly assigned to an oxytocin bolus alone, oxytocin 5 U administered intravenously over 1 minute, or an oxytocin bolus plus a 4-hour oxytocin infusion at a rate of 10 U/hr. The 4-hour postoperative oxytocin infusion was formulated by adding 40 U of oxytocin to 500 mL saline and infusing the solution at 125 mL/hr, equivalent to 0.167 U of oxytocin per minute. In this trial, 65% of the women were undergoing a repeat cesarean delivery and 35% were undergoing a primary cesarean delivery.

The authors reported that women who received the oxytocin bolus alone were significantly more likely to be diagnosed with uterine atony requiring additional uterotonic treatment than women who received both the bolus and the 4-hour postoperative infusion (18.4% versus 12.2%, respectively; P <.001). There was no difference in the rate of PPH between the two groups.

The rate of PPH was 16% in women receiving an oxytocin bolus alone and 15.7% in women receiving both an oxytocin bolus and the continuous oxytocin infusion. However, among less experienced surgeons, the rate of PPH was significantly greater in the group that received the oxytocin bolus alone compared with the women receiving the bolus and continuous infusion (22.2% versus 17.3%, respectively). The authors concluded that obstetricians should consider using a 4-hour infusion of oxytocin following cesarean delivery to reduce the risk of uterine atony.

In a recent evidence-based review of optimal interventions in cesarean delivery, the authors recommended an IV infusion of 10 to 40 U of oxytocin administered over 4 to 8 hours after cesarean delivery.7 Following cesarean, an IV infusion of crystalloid solution is typically maintained for at least 4 to 8 hours. Consequently, adding oxytocin (which costs approximately $1 for 10 units) to the crystalloid infusion does not add substantially to the cost of the patient’s postoperative care and may reduce the risk of uterine atony and PPH.

Related article: Act fast when confronted by a coagulopathy postpartum Robert L. Barbieri, MD (Editorial, March 2012)

My bottom-line recommendation. In the United States, we should adopt a policy of maintaining a continuous infusion of oxytocin for 4 to 8 hours following a cesarean delivery. Following a 4- to 8-hour rule will decrease the rate of uterine atony and excessive bleeding, thereby improving the safety of our cesarean delivery surgery. 

INSTANT POLL
How many hours following cesarean delivery do you think that an oxytocin infusion should be maintained to reduce the risk of uterine atony and postpartum hemorrhage?
If the patient is a Jehovah’s Witness and refuses the transfusion of all blood products, how many hours following cesarean delivery do you think that an oxytocin infusion should be maintained to reduce the risk of uterine atony and postpartum hemorrhage?
Tell us—at [email protected] Please include your name and city and state.

CASE: DISCONTINUED OXYTOCIN LEADS TO POSTPARTUM HEMORRHAGE
You have just completed a repeat cesarean delivery for a 41-year-old woman, now G2P2. You order an infusion of oxytocin, 20 U in 1 L lactated Ringer’s solution, to run at a rate of 125 mL/hr for 8 hours. Without informing you, the recovery room nurse discontinues the bag with the oxytocin solution and starts an infusion of lactated Ringer’s solution without oxytocin.

One hour later, you are called to the recovery room because your patient is having a postpartum hemorrhage (PPH). Physical examination shows that the uterus is boggy and above the level of the umbilicus. On ­bedside ­ultrasonography, the uterine cavity is demonstrated to contain minimal blood, and Doppler sonography does not demonstrate any vascular tissue within the uterine cavity. You diagnose uterine atony and initiate treatment. You massage the uterus, rapidly infuse 1 L crystalloid solution, place misoprostol 800 µg in the rectum, and reinitiate the oxytocin infusion. The uterine bleeding slows and then stops.

The following morning, the patient’s hematocrit has decreased from a preoperative value of 37% to 21%.  

Could this case of PPH have been prevented?

Cesarean delivery is one of the most commonly performed major operations in developed countries. More than 1,250,000 cesarean deliveries are performed annually in the United States. In 2012, there were 3,952,937 births and a cesarean delivery rate of 32.8%.¹ It is an important goal of obstetric care providers to continuously improve our approach to cesarean delivery in order to minimize the surgical risks of this procedure. Evidence-based, standardized protocols for cesarean delivery are critical to ensuring high- reliability surgical outcomes.

A key gap in cesarean delivery protocols is the lack of a nationwide, standardized approach to reducing the risk of postoperative bleeding by maintaining a continuous infusion of oxytocin in the hours immediately following cesarean delivery. 

OXYTOCIN: A CRITICAL INTERVENTION TO PREVENT PPH
More than half of all maternal deaths occur in the 24 hours following delivery, with the most common cause being PPH.² In addition to death, serious complications of PPH include coagulopathy, shock, emergency hysterectomy, transfusion complications, respiratory distress, and pituitary necrosis. Most cases of PPH that occur within 24 hours of delivery are caused by uterine atony.³ Other causes include retained products of conception, placenta accreta, infection, coagulation defects, and amniotic fluid embolism.

Administering a uterotonic such as oxytocin at the time of delivery reduces the risk of PPH by approximately 66% and the risk of maternal blood transfusion by about 65%.⁴ In order to prevent uterine atony and PPH, oxytocin should be routinely administered following birth of the baby or after delivery of the placenta. Appropriate doses following vaginal delivery are oxytocin 10 U administered intramuscularly or 10 U administered as a slow intravenous (IV) infusion.⁵ The onset of action of oxytocin is approximately 2 to 5 minutes after an intramuscular dose and 1 minute after an IV dose.⁶ 

Related article: Routine use of oxytocin at birth: just the right amount to prevent postpartum hemorrhage  Robert L. Barbieri, MD (Editorial, July 2012)

OXYTOCIN AND CESAREAN DELIVERY
Many clinical trials have reported that during a cesarean delivery, the routine administration of a uterotonic agent following birth of the baby reduces the risk of uterine atony and excessive bleeding. Three uterotonics: oxytocin, misoprostol, and carbetocin (a long-acting oxytocin analogue, see SIDEBAR), have been reported to reduce the risk of excessive bleeding during cesarean delivery.⁷ Oxytocin is the uterotonic most commonly used during cesarean delivery in developed countries. 

Related article: A new (to the US) first-line agent for heavy menstrual bleeding Robert L. Barbieri, MD (Editorial, October 2010)

In the United States, there is no standardized oxytocin regimen for prevention of uterine atony and hemorrhage at cesarean delivery. The most common regimen is to add 10–40 U of oxytocin in 1 L crystalloid solution and initiate the oxytocin infusion following delivery of the baby. Initially, the infusion is run at a rapid rate. Once the obstetrician reports that there is adequate uterine tone, the infusion rate is slowed to one that maintains uterine tone.

Some clinicians administer a single bolus of oxytocin following birth of the baby. However, a bolus of oxytocin commonly causes hypotension and, less commonly, ST segment changes on the electrocardiogram (EKG) suggestive of cardiac ischemia.^8–10Many experts recommend against administering one large bolus of oxytocin over a short period of time and favor a continuous infusion.

At cesarean delivery, the minimum infusion rate of oxytocin that has been reported to avoid most cases of uterine atony, as reported by the obstetrician immediately following delivery, is approximately oxytocin 0.3 U/min.¹¹ Oxytocin infusion rates of 0.2 U/min and 0.1 U/min were associated with uterine atony rates of 21% and 40%, respectively. An infusion rate of oxytocin 0.3 U/min can be achieved by the administration of 20 U of oxytocin in 1 L crystalloid solution at a rate of 15 mL/min until uterine tone is achieved. The oxytocin dose then can be titrated to maintain adequate uterine tone. Following completion of surgery, uterine tone can be maintained with a low-dose continuous infusion of oxytocin.  

4- TO 8-HOUR OXYTOCIN RULE
A key gap in our cesarean delivery protocols is a standardized recommendation concerning the duration of the oxytocin infusion following cesarean delivery. To my knowledge, no national organization has made a firm recommendation concerning the duration of oxytocin infusion following cesarean delivery.

One recent clinical trial studied PPH following cesarean delivery utilizing two oxytocin regimens: a bolus of oxytocin following delivery of the baby versus a bolus of oxytocin followed by a 4-hour IV infusion of oxytocin.¹² In this trial, 2,058 women undergoing a scheduled cesarean delivery with a singleton pregnancy were randomly assigned to an oxytocin bolus alone, oxytocin 5 U administered intravenously over 1 minute, or an oxytocin bolus plus a 4-hour oxytocin infusion at a rate of 10 U/hr. The 4-hour postoperative oxytocin infusion was formulated by adding 40 U of oxytocin to 500 mL saline and infusing the solution at 125 mL/hr, equivalent to 0.167 U of oxytocin per minute. In this trial, 65% of the women were undergoing a repeat cesarean delivery and 35% were undergoing a primary cesarean delivery.

The authors reported that women who received the oxytocin bolus alone were significantly more likely to be diagnosed with uterine atony requiring additional uterotonic treatment than women who received both the bolus and the 4-hour postoperative infusion (18.4% versus 12.2%, respectively; P <.001). There was no difference in the rate of PPH between the two groups.

The rate of PPH was 16% in women receiving an oxytocin bolus alone and 15.7% in women receiving both an oxytocin bolus and the continuous oxytocin infusion. However, among less experienced surgeons, the rate of PPH was significantly greater in the group that received the oxytocin bolus alone compared with the women receiving the bolus and continuous infusion (22.2% versus 17.3%, respectively). The authors concluded that obstetricians should consider using a 4-hour infusion of oxytocin following cesarean delivery to reduce the risk of uterine atony.

In a recent evidence-based review of optimal interventions in cesarean delivery, the authors recommended an IV infusion of 10 to 40 U of oxytocin administered over 4 to 8 hours after cesarean delivery.7 Following cesarean, an IV infusion of crystalloid solution is typically maintained for at least 4 to 8 hours. Consequently, adding oxytocin (which costs approximately $1 for 10 units) to the crystalloid infusion does not add substantially to the cost of the patient’s postoperative care and may reduce the risk of uterine atony and PPH.

Related article: Act fast when confronted by a coagulopathy postpartum Robert L. Barbieri, MD (Editorial, March 2012)

My bottom-line recommendation. In the United States, we should adopt a policy of maintaining a continuous infusion of oxytocin for 4 to 8 hours following a cesarean delivery. Following a 4- to 8-hour rule will decrease the rate of uterine atony and excessive bleeding, thereby improving the safety of our cesarean delivery surgery. 

INSTANT POLL
How many hours following cesarean delivery do you think that an oxytocin infusion should be maintained to reduce the risk of uterine atony and postpartum hemorrhage?
If the patient is a Jehovah’s Witness and refuses the transfusion of all blood products, how many hours following cesarean delivery do you think that an oxytocin infusion should be maintained to reduce the risk of uterine atony and postpartum hemorrhage?
Tell us—at [email protected] Please include your name and city and state.