Utilizing A Standard Regimen For The Use Of Oxytocin

A Review: Original Article AJOG June 2008

Oxytocin (Pitocin) is among the most commonly used medications for labor and delivery. At least 33.2% of women will receive oxytocin while they are in labor. Before 2008, there was no standard protocol for oxytocin administration in labor. In fact, “pit to distress” was not an uncommon management strategy. In 2008, Dr. Edward J Hayes, MD, and Louis Weinstein, MD, constructed a standardized protocol for labor induction with oxytocin. They reviewed numerous publications regarding oxytocin use for induction and augmentation to determine if there was a protocol that would maximize delivery success and minimize the adverse maternal and fetal effects of the drug. Utilizing their literature review, they developed a standardized approach for the dilution and administration of oxytocin to ensure patient safety, uniformity of the drug, and to enhance its benefits while minimizing side effects.

Oxytocin is a hormone produced by the hypothalamus and transported to the posterior lobe of the pituitary. From the posterior lobe of the pituitary, it is secreted into the bloodstream by a pulsatile mechanism. Synthetic oxytocin is based on the naturally occurring hormone. The half-life of oxytocin has a range from 3 to 10 minutes, with a steady state after starting it or changing the dose occurring at about 40 minutes.3 Studies have shown that the time to steady state after the drug is started is also about 40 minutes, corresponding with maximum contraction response. In correlating an infusion rate of 4-6 mU/min, serum levels are obtained that correspond to the spontaneous levels of oxytocin during the first stage of labor.

Clinically, oxytocin has been associated with significant maternal and fetal difficulties. Adverse events affecting multiple organs in the mother have been recognized, including cardiac arrhythmias, blood pressure issues, hyperstimulation of the uterus, and hyponatremia. Oxytocin-induced labor has also been associated with adverse neonatal effects, including seizures, hyperbilirubinemia, and retinal hemorrhage. These adverse outcomes prompted the Food and Drug Administration to assign a black box warning on oxytocin, indicating that the medication should be restricted to medically indicated inductions and augmentations of labor and not used for the elective induction of labor.

The association of oxytocin with adverse outcomes can be seen in obstetric/midwifery malpractice claims. A review of 77 malpractice cases showed that the injudicious use of oxytocin (meaning the increase of the rate of administration in the midst of non-reassuring fetal heart rate tracings or hyperstimulation of the uterus occurred in 68% of cases and was the main reason for disciplinary action by the Board of Medical Responsibility in 33% of the cases. One study regarding the use of oxytocin in malpractice cases involving neonatal death and neurologically impaired infants demonstrated that the drug’s use during labor decreased the chance of a successful defense for doctors and hospitals. It was also observed that a common recurring problem in these cases was the inappropriate use of oxytocin, leading to uterine hyperstimulation, uterine rupture, non-reassuring fetal status, physiologically depressed newborns at birth, long-term neurological problems, and fetal death.

In developing a standardized protocol, the first variable to be determined was a standard starting dose. Considering that the physiological level of oxytocin during labor is reached by an infusion rate of 4-6 mU/min, starting at this level or higher would not follow the physiological course of labor. The initial dose that the researchers suggested was 2 mU/min because this theoretically allowed for variation in uterine sensitivity and was supported by clinical experience.

To standardize drug administration, the authors suggested using a uniform concentration of 10 U of Oxytocin in 1000 mL of normal saline. This results in a concentration of 10mU/mL. The same concentration can be made by putting 2.5 U of Oxytocin in 250 mL of normal saline. This initial rate of 2 mU/min would be obtained at an infusion rate of 12mL per hour. Timing of dose adjustments should be based on the half-life of the medication and the time it takes to reach a steady state.

1. Dilution -> 2. Initial Dose

10 units of oxytocin in 1000 mL of normal saline, 2 milliunits per minute

(2.5 units of oxytocin in 250 mL or normal saline Infusion rate of 12 mL per hour

Resulting Concentration – 10 milliunits oxytocin per mL

4. Maximum dose <- 3. Incremental Increase

16 milliunits per minute Increase by 2 milliunits per minute (12 mL per hr)

(96 mL per hour) every 45 minutes until adequate labor

Hayes. Improving patient safety and care by a standardized regimen for oxytocin. Am J Obstet Gynecol 2008;198:622.e1-622.e7

Timing of dose adjustments should be based on the half-life of the medication and the time it takes to reach a steady state. It is essential to acknowledge variation within a patient population when establishing a standardized dosing regimen,. To minimize the incidence of hyperstimulation, we utilized the longer reported half-life of 10 minutes, resulting in a dosing interval of approximately 45 minutes. Using this suggested dilution, the protocol would have the infusion rate increase every 45 minutes by an increment of 12 mmL/h

The most controversial part of this standardized protocol is the maximum dose. The protocol suggests a maximum infusion of 16 mU/min or 96 mL per hour. This level is about 3 times that of the normal physiologic oxytocin level generated in spontaneous labor, and though higher doses have been used, they have never been shown to decrease the incidence of cesarean delivery and are associated with higher rates of hyperstimulation.

A small percentage of laboring patients may need a higher dose; these authors recommend that this be an exception requiring clinical evaluation and justification, along with a corresponding note in the medical record describing the reasoning behind the decision for a higher dose.

Situation: For most hospitals in the United States, today, this protocol is essentially unchanged. The medical legal issue, however, is the unsafe practice by providers of overriding the protocol, either on their own or after consultation. Generally, nurses can request to increase the oxytocin outside the protocol, following consultation with the treating physician or midwife.

Vulnerability: Generally, nurses can request to increase the oxytocin outside the protocol, following consultation with the treating physician or midwife. The issue is not the desire or request to raise the dosage above the protocol. It is with the doctor or midwife who approves the override without reviewing the fetal monitoring strip in person. Many legal cases originate from a lack of fetal strip evaluation pbeforeincreasing oxytocin above 16 mU/min. A typical scenario involves nursing staff who decide the patient’s progress has stalled and the only way to get the patient on track for a vaginal delivery is to turn up the Pit.

Expectation/Duty: The most critical assessment, however, may be left out;:the fetal heart rate tracing. Although patient progress has stalled, simultaneously there may be a monitor strip that is showing abnormalities such as late decelerations, tachysystole, hypertonus or persistent deep variables. If the nurse doesn’t recognize these or fails to evaluate the strip before increasing oxytocin above protocols, this can lleadto fetal or maternal harm and, eventually, a lawsuit.

Nurses aren’t the only ones to find themselves in court. The nurses may brequesta consultation and evaluation ,but the midwives or doctors refuse to come to the bedside to eassessthe patient’s situation. This is an ongoing problem that has not resolved. The nurse calls the provider. The provider responds to the nursing request without seeing the patient. An order is given by the provider to increase oxytocin without evaluating the monitor tracing or the patient in person. A baby or mother’s condition is deteriorates. Permanent damage occurs. Everyone gets sued.

Remedies/Protection:

With the advent of hospitalists, there is no reason for a patient to not be evaluated, personally, when there is a sudden change or deterioration in their condition. If there is a valid reason for why you will be delayed, or cannot come to the bedside, get someone else to evlauate your patient. This is not ideal, but as the responsible provider, you are, at least summoning help while you are on your way. If you are taking your call at home and not personally evaluating concerning changes in your patient’s condition, you can be found negligent in a court case.

Finally, from a medical/legal standpoint, if your patient has been admitted in active labor, is being induced, or a triage evaluation indicates a potential problem, you need to be at the hospital, not at home in bed. On call means that you are the one responsible for making decisions and providing the critical evaluations necessary. If there is a problem, you need to be with your patient. Period. A legal team evaluating what went wrong with your patient will be more than happy to report, on an initial legal complaint, that your patient needed you and you were not even there. It looks bad for you, legally, and makes proving negligence against you almost effortless.

Refer to: Cheating on Call; Parts I and II.

References:

1. Improving patient safety and uniformity of care by a standardized regimen for the use of oxytocin. American Journal of Obstetrics & Gynecology. June 2008. Edward J. Hayes, MD, MSCP; Louis Weinstein, MD. pp. 622. e1. - 622, e6. From the Department of Obstetrics and Gynecology, Thomas Jefferson University, Philadelphia, PA. http://www.AJOG.org.

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