Hypertensive crisis merging with paroxysmal supraventricular tachycardia after dezocine injection during cesarean delivery: A case report

Abstract

Hypertensive crisis and paroxysmal supraventricular tachycardia are serious adverse reactions that can lead to fatal consequences. We reported a 28-year-old woman who underwent emergency cesarean section of her first fetus due to pelvic outlet stenosis and had a hypertensive crisis, merging with paroxysmal supraventricular tachycardia after dezocine was administrated during the procedure. Her symptoms returned to normal after esmolol and urapidil were administrated. In order to rule out hypertension crisis caused by other diseases, the anesthesiologist immediately accessed the thyroid function, myocardial enzymes, catecholamines, and arterial blood gas analysis of the patient. No obvious abnormality was found in all the test results. We infer the conclusion that the symptoms of this patient during the operation were most likely related to dezocine administration. This case highlights the need to pay attention to possible malignant adverse reactions while using dezocine during cesarean section, and we recommend the immediate use of α-receptor blockers and/or β-receptor blockers in situations like to avoid serious complications caused by supraventricular tachycardia.

Introduction

Cesarean section is a surgical procedure that effectively prevents maternal and newborn mortality when appropriately indicated. The rate of 10%–15% has been considered by the international healthcare community since 1985 as the ideal rate of cesarean sections. ¹ Nowadays, cesarean section rates have increased steadily worldwide over the last decades in both high-income and low- and middle-income countries. In China, the cesarean section rate has increased from 5% in the 1960s to 20% in the early 1990s, and the rate has continued to rise in the last 20 years. A global survey conducted by the World Health Organization (WHO) reported that 46.2% of births were delivered by cesarean section in China during 2007–2008. ²

With the rapid progress in medical technology, analgesic drugs that can be used in obstetrics are gradually increasing. Dezocine is a novel opioid receptor antagonist that has been used mainly as a postoperative, visceral, and carcinogenic analgesic. In general, the peak value can be reached within 10–90 minutes after intramuscular or intravenous injection, and the average terminal half-life is 2.4 h. ³ The analgesic effect is similar or slightly higher than that of morphine, but with less mental dependence and fewer related adverse reactions. Dezocine can be safely and effectively used for postoperative obstetric analgesia.^4,5 However, its uncommon serious adverse drug reactions were rarely reported. We report hypertensive crises merged with paroxysmal supraventricular tachycardia (PSVT) after intravenous administration of 5 mg of dezocine.

Case report

A 28-year-old woman with a weight of 78 kg and a height of 169 cm at 38 weeks of gestation underwent an emergency cesarean section on account of pelvic outlet stenosis in November 2021. Pelvic outlet stenosis refers to the pregnant woman with a normal inlet but a greatly narrowed outlet which can lead a disproportion between the fetal head and pelvis. She had no history of preeclampsia, anticoagulation therapy, or hemorrhagic diathesis. Physical examination and preoperative blood tests including the coagulation function and urine analysis were all within normal limits. The most recent electrocardiogram (ECG) in pregnancy showed sinus tachycardia with a heart rate of 108 beats/min. When the patient arrived in the operating room, the L3 to L4 subarachnoid space was accessed at the first attempt using a 27-gauge needle, and 10 mg of 0.375% bupivacaine was injected into the subarachnoid space. The fetus was delivered, and the uterus and the anterior abdominal wall were repaired in layers. The patient had pains at the closure of the skin and 5 mg of intravenous dezocine was slowly administered over 1 minute. She subsequently presented with hypertensive crisis merging with PSVT. The fastest heart rate was 178 beats/min and the highest blood pressure was 190/128 mmHg (Table 1). She was given esmolol (20 mg) and urapidil (12.5 mg). After 3 min, the patient regained an effective heart rate, and her blood pressure returned to normal limits. After observation in the recovery room intensive care unit (ICU) for an hour, the patient was returned to the ward. Further interrogation of the patient revealed that there was no prior history of PSVT or hyperthyroidism.

Table 1.

Vital sign parameters after dezocine administration.

Time (mm:ss)	Vital sign parameters
	Heart rate (beats/min)	Blood pressure (mmHg)
11:45 (T1)	104	126/73
11:47	158	NA
11:48 (T2)	178	190/128
11:49	140	190/128
11:50	104	173/112
11:51 (T3)	104	98/58
11:52	103	101/64

After the injection of dezocine, the patient presented symptoms of rapid heart rate and elevated blood pressure. T₁: dezocine administration; T₂: time point of the fastest heart rate and highest blood pressure; T₃: recovered to normal heart rate and blood pressure after esmolol and urapidil administration.

In order to determine the possible cause of the hypertensive crisis merging with PSVT, the anesthesiologist immediately accessed the thyroid function, myocardial enzymes, catecholamines, and arterial blood gas analysis. However, all the requested investigations were within normal limits. Because the entire cesarean section process was smooth, oxytocin was not used, and the amount of bleeding was approximately 320 mL, which ruled out the cause of oxytocin. Due to less bleeding and good uterine contraction of the pregnant woman, the surgeon decided not to use drugs to constrict the uterus.

After close observation in the recovery room ICU for an hour, the patient was returned to the ward without discomfort. The patient enjoyed the compliments from obstetrics, anesthesiology, and cardiology departments’ multidisciplinary care. The cause of the hypertensive crisis merging with PSVT was finally suggested to be from intravenous administration of dezocine. There was no special discomfort in the patient’s heart during the follow-up visit the next day, and the results of cardiac color Doppler ultrasound were normal. Subsequently, her course was uneventful and she returned home 5 days later.

Discussion

Dezocine is a novel opioid receptor antagonist that can be safely and effectively used for postoperative analgesia. Dezocine has less mental dependence than other opioids. PSVT is a type of abnormal heart rhythm, or arrhythmia. PSVT occurs when a short circuit rhythm develops in the upper chamber of the heart and it can result in a regular but rapid heartbeat that starts and stops abruptly. ⁶ We diagnosed the patient’s PSVT by ECG. A hypertensive crisis is a sudden, severe increase in blood pressure. The blood pressure value is 180/120 mmHg or greater. Hypertensive crisis and PSVT are medical emergencies that can lead to cerebrovascular accidents, acute heart failure, and even cardiac arrest.

The appearance of a hypertensive crisis merging with PSVT linked to the injection of dezocine is the most probable explanation of our report. Although there are no relevant studies or medical records, it is mentioned in the drug manual that a patient had tachycardia after intramuscular injection of dezocine, with a maximum heart rate of 112 beats/min. ⁷ Considering that the hypertensive crisis caused by occult pheochromocytoma requires some inducements, we think that it was unlikely to diagnose occult pheochromocytoma. ⁸ Furthermore, because the patient’s plasma and urinary catecholamine investigations were within normal limits, we ruled out the possibility of pheochromocytoma. The mechanism of dezocine-induced supraventricular tachycardia complicated by a hypertensive crisis remains unclear. Although dezocine is widely used for postoperative analgesia,^9,10 its possible malignant adverse reactions need to be monitored carefully.

Hypertensive crisis merging with PSVT after dezocine injection is a rare event, but dezocine is becoming dominated in China market for relieving moderate to severe pain. Due to our aggressive treatment, despite the rapid onset and severe presentation in our case, our patient survived. Our case report emphasizes the judicious use of dezocine so as to avoid and reduce similar untoward events.

Conclusion

In conclusion, parenteral dezocine administration could lead to hypertensive crisis merging with PSVT, and therefore, its use must be closely monitored in all patients especially during surgeries. Once supraventricular tachycardia occurs, we recommend using α-receptor blockers and/or β-receptor blockers as soon as possible to avoid serious complications.