Successful Management of Intraoperative Priapism under General Anesthesia during Transurethral Surgery - A Case Series with Review of Its Management.

Penile erection under general anesthesia is a rare occurrence. It may cause delay, complications or can even lead to cancellation of an elective transurethral surgery. In literature, various methods and techniques have been mentioned with variable rates of success and side effects. However, the management becomes challenging and it needs a tailored approach according to the patient's clinical condition with the aim of minimizing complications. Hereby, reporting two cases of successful management of intraoperative priapism in patients undergoing transurethral surgery under general anesthesia. Copyright:

INTRODUCTION

Penile erection under general anesthesia is a rare complication. The exact pathophysiology of perioperative erection is unclear with a reported incidence of about 0.1%–2.4%.[12] During transurethral surgery, sustained erection may cause delay, complications or can even lead to cancellation of an elective surgery. Surgery in such circumstances may be associated with bleeding, stricture formation, and other serious postoperative penile complications, which may have medico-legal implications.[3]

CASE SERIES

Case 1

A 25-year-old male, diagnosed with anterior urethral stricture was posted for substitution urethroplasty under general anesthesia. The patient was the American Society of Anesthesia (ASA) Physical status Class I with unremarkable history and investigations. His preoperative vitals were within normal limits. Induction of anesthesia and endotracheal intubation was done with fentanyl 100 micrograms (μg), propofol 100 milligrams (mg), and vecuronium 6 mg. Anesthesia was maintained with sevoflurane, oxygen, and air. After positioning the patient and just before the instrumentation for the transurethral procedure a rigid penile erection was noted. There was no obvious change in his vitals. The penile erection persisted for more than 10 min and there was no improvement in it. Therefore, it was suspected to be a case of propofol-induced priapism. Two mL of 1:100,000 epinephrine was injected into both cavernosal bodies with utmost care to prevent any puncture to deep penile artery [Figure 1a]. Complete penile detumescence was observed after 5 min of epinephrine injection. There were no significant alterations in blood pressure (BP) and heart rate or other obvious side effects after epinephrine administration. Subsequently, surgery was started and completed. The patient was extubated uneventfully with stable hemodynamics.

Figure 1

(a): Intracavernous injection of epinephrine (b): Left dorsal penile nerve block (c): Right dorsal penile nerve block

Case 2

A 68-year-old ASA physical status class II male, was posted for transurethral resection of a bladder tumor (TURBT). The patient was known hypertensive and his BP was well controlled with tablet amlodipine 10 mg once a day. Rest of his perioperative vitals and investigations were within normal range. On the day of surgery, he continued his tablet amlodipine early morning with a sip of clear water. General anesthesia with supraglottic airway insertion was planned. After attaching standard ASA monitors and securing an intravenous (i.v.) access, anesthesia was induced with i.v. fentanyl (2 μg.kg− 1), propofol (1–2 mg.kg− 1), and vecuronium (0.1 mg.kg− 1) followed by the insertion of I-gel size 4. Anesthesia was maintained with sevoflurane to achieve a minimum alveolar concentration of 0.8–1 in 40% oxygen. Just after the lithotomy position, a rigid penile erection was noted. The urethroscope could not be negotiated by the operating surgeon and so further penile stimulation and instrumentation were avoided. Adequate time was given so as for the erection to settle and become flaccid. Even after the local application of an ice pack for 5 min, the erection could not resolve. Injection glycopyrrolate 0.2 mg was given intravenously. However, there was no obvious improvement in the condition. Intracavernous injection of sympathomimetic drugs such as phenylephrine, noradrenaline, adrenaline and metaraminol, ketamine, terbutaline, and dexmedetomidine was avoided as the patient was elderly and hypertensive. Finally, bilateral dorsal penile nerve block using landmark technique was planned. The skin was pinched and pierced with a 23 gauge needle at a 2 o'clock position to block the left dorsal nerve of penis. After crossing the superficial (Dartos) fascia, the needle was inserted further to pierce the deep (Buck's) fascia until a pop was felt. 8 ml of 0.5% levobupivacaine was deposited after careful aspiration for blood [Figure 1b]. The same was repeated on the other side at 10 o'clock position to block the right dorsal nerve of penis [Figure 1c]. Complete penile detumescence was observed after 10 min with no significant changes in his hemodynamic parameters. Thereafter, TURBT was successfully accomplished.

DISCUSSION

Sustained penile erection which is not related to sexual activity is called priapism. Most penile erections are idiopathic in nature; however, they can occur due to the use of certain drugs such as antihypertensive, antidepressants, and recreational drugs. It may also be seen in certain medical conditions such as polycythemia, leukemia, pelvic thrombophlebitis, spinal cord injury, trauma to pelvis, syphilis, and urethritis.[4]

Penile erection under general anesthesia is a rare occurrence but it is important to have a clear understanding of the pathophysiology behind it so that the management can be customized according to the patient's clinical condition. Early diagnosis and treatment is the key behind the successful management of perioperative erection. Any delay in recognizing and or treating it can lead to serious postoperative complications.[5]

The exact mechanism of erection under anesthesia is little understood. Erection is a dynamic process balancing the exciting and inhibiting forces of the autonomic nervous system within the penis and the central nervous system. The sympathetic pathways (T10 to L2) inhibit erections and the excitatory parasympathetic system (S2 to S4) is responsible for erection. Disturbance of the sympathetic and parasympathetic nervous system balance can provide one of the simplest explanations for the complex mechanism of erection under anesthesia. During general anesthesia or central neuraxial blockade, sympathetic outflow from lower thoracic and higher lumbar spinal segments is lost. Stimulation of genitalia during skin preparation and instrumentation before complete sensory blockade can activate the sacral parasympathetic pathways for an unopposed reflex response. This results in a state of autonomic imbalance leading to erection.[6] However, apart from the autonomic nervous system, many other factors such as noncholinergic, nonadrenergic, and local neurotransmitters are also involved in the complex process of erection.[7]

Erection under anesthesia can occur under any type of anesthetic technique. It has been predominantly seen in young male, with an incidence of 0.34% under general anesthesia and 1.83% under central neuraxial blocks.[6] Two proposed mechanisms of erection under general anesthesia are psychogenic and reflexogenic in nature.[8] Dreams under anesthesia contribute to psychogenic stimulation, whereas local stimulation and instrumentation give reflexogenic stimuli from sacral roots. Few medications such as propofol and fentanyl which are used for inducing general anesthesia have been reported to cause intraoperative erections.[91011]

Among central neuraxial blocks, the occurrence of erection in epidural anesthesia (1.72%) is greater compared to spinal anesthesia (0.11%).[6] The exact reason for this variation in occurrence is still unclear. During early stages of the neuraxial block, there is incomplete blockage of sacral segments (S2 to S4). Tactile stimuli under such conditions, when there is insufficient depth of anesthesia, reflexogenic stimulation can be triggered leading to erection.[5]

Treatments

In literature, various methods to manage intraoperative priapism have been mentioned. It includes decreasing the sensory input to penis (with the application of ice, ethyl chloride, or dorsal nerve block) and the use of pharmacological drugs through various routes. Contrary to the previous assumption, deepening of anesthesia has no role in its management. Hence, it is not considered an effective mode of treatment nowadays.[1] Aspiration of blood from corpora cavernosa and surgical shunting are the last options available in a resistant case where other traditional methods of treatment fail.

The use of ice, ethyl chloride, and dorsal nerve block acts by interrupting sacral reflex (S2 to S4) as the sensory input to penis is reduced. In our second case, we have used bilateral dorsal penile nerve block using 0.5% levobupivacaine. Postblock scan using ultrasound can be done to see the spread of local anesthetic below the Buck's fascia. However, in our case, we failed to scan as complete detumescence was achieved before arranging the ultrasound machine.

Various pharmacological treatments have been suggested for managing intraoperative erection. These include the administration of drugs through intracavernous, i.v., and respiratory routes. Epinephrine, norepinephrine, phenylephrine, and metaraminol are injected intracavernous.[12131415] Utmost care should be taken during the process, as direct intracavernous injection may result in hematoma, infection, pain, or even fibrosis of the penis.[810] Inadvertent i.v. injection may result in hypertensive crisis, pulmonary edema, and even death.[16]

Epinephrine is the most commonly used drug for intracavernous injection, as it is easily available in operation theater. In our first case, we have managed with 2 mL of 1:100,000 epinephrine which was injected into both cavernosal bodies. Penile bruising is one of the most common complications encountered. It is considered to be safe, however, if a surgeon is administrating, anesthesiologist must be informed before the procedure. Repeating intracavernous injection is considered to be unsafe and thus avoided. In our second case, the use of any sympathomimetic agent was avoided as the patient was a known hypertensive. Therefore, the patient's clinical condition and their comorbidities must be kept in mind before its use. Close monitoring of patient's hemodynamics and drugs to deal with cardiovascular side effects such as hypertensive crisis or arrhythmia should be readily available in the operation theater. However, in our case, no obvious side effects were seen during intra- or post-operative period.

i.v. injection of ketamine, glycopyrrolate, dexmedetomidine, terbutaline, and salbutamol metered-dose inhaler (MDI) has been also suggested.[5614171819] Ketamine is one of the popular choices among the i.v. drugs, but it takes a longer time (90–120 min) to achieve complete flaccidity.[1820] Hypertension, hallucinations, and unpleasant dreams are the common side effects. It was therefore avoided in the second case of management.

As parasympathetic activation plays a significant role, i.v. glycopyrrolate has been found helpful in few cases of erection.[17] Glycopyrrolate being a quaternary ammonium compound has less side effects and is better tolerated in elderly patients. In both the cases, premedication with glycopyrrolate or atropine was not given as it is avoided according to our institutional protocol for elective surgeries. However, glycopyrrolate 0.2 mg was given intravenously in the second case, but there was no obvious improvement in his condition.

In a study by Guler et al. involving 12 cases of intraoperative penile erections, i.v. injection of dexmedetomidine (selective α-2 adrenoreceptor agonist) at a dose of 0.5 μg.kg− 1 was given. They found it to be a safe, simple, and effective method for immediate relief of penile erection with a good success rate in 83% of cases.[6] It may be associated with bradycardia and hypotension, however, no active intervention was needed in any of the cases.

Among the beta-2 adrenergic agonists, terbutaline has proved beneficial in enhancing the penile venous drainage. It helps in smooth muscle relaxation in the cavernous body, tunica albuginea, veins, and arteries, thus easing out the blood flow from the arteries, cavernous sinusoids, and capillaries and then through the veins.[5] Tachycardia, pulmonary edema, and hypokalemia are associated side effects of terbutaline.

Salbutamol is a beta-2-adrenergic agonist which causes relaxation of smooth muscle that leads to vasodilation and bronchodilation. The administration of salbutamol aerosol by a MDI in a mechanically ventilated patient has been found to be beneficial in treating intraoperative penile erection.[10]

Proper documentation of events related to anesthesia, penile erection, and its management should be done. In future, the suspected drugs or conditions causing erection are to be avoided ensuring better patient safety and satisfaction.

CONCLUSION

Intraoperative penile erection is a rare but troublesome complication during urological surgery. Early diagnosis and initiation of treatment according to the patient's profile is the cornerstone for its management. Among various options available, no single method of treatment can be considered to be ideal. It should be tailored according to the patient's clinical condition, availability of resources with an aim to minimize side effects and complications. In transurethral surgeries, erection can be avoided by limiting tactile stimuli of the penis till a sufficient depth of anesthesia is achieved. Dorsal penile nerve block and intracavernous injection of epinephrine are safe and effective procedures. They can be considered as an early method of treatment in case of intraoperative penile erection until contraindicated.

Declaration of patient consent

The authors certify that all appropriate patients' consent forms have been obtained. The patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.