Trinitrate

Uterine contractions cause hypoxic stress to human fetuses by repeatedly occluding maternal spiral arterioles which feed the placental bed and/or compressing the loops of the umbilical cord, interrupting blood flow through the umbilical vessels. For some fetuses, even such transient and repeated interruptions of oxygenation due to ongoing uterine contractions may increase the risk of decompensation in the "high priority" central organs (i.e. heart and the brain). The onset of anaerobic metabolism and resultant production of lactate in the central organs may lead to increased likelihood of fetal neurological injury and/or perinatal death. Therefore, an immediate relaxation of the myometrium by abolishing ongoing uterine contractions may help to rapidly restore oxygenation to fetal central organs. Such timely administration of acute tocolytics would help maintain aerobic metabolism in the high-priority fetal central organs, avoiding the onset of neurological injury and/or perinatal death. Commonly used acute tocolytics include beta-sympathomimetics, nitric oxide donors, oxytocin antagonists, which have different mechanisms of actions, and maternal side-effect profile. The indications include elimination of uterotonic-induced excessive uterine contractions to facilitate normalization of the fetal heart rate so as to allow continuation of labor in anticipation of vaginal birth and for rapidly improving the fetal condition immediately prior to an emergency cesarean section. The latter includes umbilical cord prolapse or chronic hypoxia when a delay in birth is anticipated. This review addresses the indications for acute tocolytics (why), the recommended timing of administration (when), ideal tocolytic (what), route of administration (how), side effects and contraindications (why-not). Based on current evidence, and pharmacokinetics, 250 mcg of subcutaneous terbutaline (or another beta-sympathomimetic such as intravenous fenoterol) is the recommended first line tocolytic, unless there are specific maternal contraindications. In the absence of maternal hypotension, 100 mg of intravenous glyceryl trinitrate (GTN) may be administered as an alternative. Acute tocolytics are not recommended to treat myometrial irritability observed in chorioamnionitis or in acute feto-maternal hemorrhage.

Acute anal fissure is a common cause of severe pain in the anorectal region. The standard treatment is the topical application of a calcium channel blocker or glyceryl trinitrate. Despite acute anal fissure being a common proctologic condition, data on the healing rates and long-term outcomes remain scarce. This study aimed to evaluate data from our centre, with a special focus on long-term follow-up and recurrent disease.

All consecutive patients who presented with acute anal fissure between January 2016 and December 2016 were retrospectively identified. Patients were included if their clinical symptoms lasted for less than 6 weeks, secondary changes to fissure morphology were absent, and data from follow-up examinations were available. Clinical features, symptoms, therapy and long-term outcomes were evaluated.

A total of 623 patients with a median age of 45 years were included; 342/623 patients were female (54.9%). The median follow-up period was 41 months (range 6 weeks-89 months), and 39.5% of the patients had a follow-up duration exceeding 5 years. Most fissures occurred in the 6 o'clock lithotomy position (63.7%), in the 12 o'clock position (21.0%), or in both (4.5%). In 67/623 patients, the fissure was in an atypical region (10.8%). In 439/623 patients, the fissure healed completely (70.5%). A total of 8.7% of the patients underwent fissurectomy, and 180/623 patients experienced recurrence (28.9%).

The management of acute anal fissure can be challenging because recurrence is common. Conservative management is successful in the majority of cases. Surgery is necessary only for a minority of patients.