The 4Ts: Directed Therapy and Definitive Treatment

The 4Ts: Directed Therapy and Definitive Treatment

The classic causes of antepartum obstetric haemorrhage are ruptured ectopic pregnancy, placenta praevia, placental abruption, vasa praevia, and uterine rupture. During the postpartum period, haemorrhage may be due to uterine atony, retained uterine products, unrecognized ongoing surgical bleeding, uterine inversion, vaginal lacerations, or placenta accreta. There must be logical and step wise approach to the diagnosis, so that effective drug and surgical therapy can be initiated. In order to establish the cause of bleeding, the lower genital tract should be examined for tears or lacerations and the uterus and pelvis should be explored if retained products, uterine rupture or uncontrolled surgical bleeding are suspected or uterine atony persists. When the underlying cause has been established, a definitive treatment plan can be made, e.g additional uterotonic drugs, surgery for lacerations or if continued bleeding after caesarean section, uterine tamponade techniques or a hysterectomy may be performed.

A practical, working classification of the causes of major obstetric haemorrhage is to use the classification of the 4Ts: Tone, Tissue, Trauma or Thrombin.

'Tone'

Mechanical

The simple 'rubbing-up of a contraction is an effective skill, which should be used early, placing a hand on the abdomen and firmly rubbing the fundus of the uterus. Bimanual compression (compressing the fundus and base of uterus together between two hands) can be used at vaginal or operative delivery and may be a life saving initial measure.

Drugs

The routine administration of uterotonic drugs at delivery can dramatically reduce the risk of haemorrhage due to uterine atony. The usual first choice of drug is oxytocin or a mixture of oxytocin and ergometrine given IM or IV. Oxytocin, ergometrine, carboprost and misoprostal are all effective and any can be used in a stepwise fashion or singularly, if only one is available, once uterine atony has been diagnosed.

Oxytocin should be given as a slow IV bolus of 5 IU, followed by an IV infusion of 40 IU over 4 hours diluted in saline in the event of anticipated or ongoing postpartum haemorrhage.

Ergometrine 05 mg IM or IV causes uterine and vascular smooth muscle contraction through 5-HT receptor stimulation. It should be used with extreme caution in pre-eclampsia and heart disease.

Misoprotol is a synthetic OGE1 prostaglandin analogue that increases uterine tone. It is administered rectally in a dose of 600-1000mcg and is very effective, easy to store and relatively inexpensive.

Carboprost (15-methyl PGF2) is a potent synthetic analogue of prostaglandin (PG) F2 alpha, which is given IM (or intra-myometrially) in doses of 250mcg. It can be repeated every 15 minutes to a maximum total dose of 2 mg. carboporost can cause hypoxia due to in trapulmonary shunting caused by pulmonary vascular smooth muscle constriction. It should NOT be given IV and should be used with caution in pre-eclampsia or heart disease.

Prostaglandins PGE1 and PGF2 stimulate myometrial contraction and should be considered if oxytocics or ergometrine fail to achieve adequate myometrial contraction.

'Tissue'

The uterus must be empty for effective contraction to occur, therefore any remaining fragments of placenta, blood clot or membranes must be removed. This can sometimes be done gently after a vaginal delivery without anesthesia, but frequently requires more detailed investigation and adequate anaesthesia. An abnormally adherent or invasive placenta, e.g accrete can pose particular problems necessitating hysterectomy.

'Trauma'

Lacerations and tears to the uterus or lower genital tract are a common and frequently under-estimated cause of hemorrhage. They must be carefully explored and repaired under anaesthesia. General anaesthesia will usually be required if bleeding is ongoing or there is any degree of haemodynamic instability. Regional anaesthesia should only be considered is the patient is fully resuscitated, haemodynamically stable and has satisfactory clotting.

'Thrombin'

Initial fluid resuscitation is based on volume replacement and clinical assessment. The Hb level is often a poor indicator of blood loss in acute bleeding. It has been shown in clinical reconstruction scenarios that blood loss is underestimated by up to 35% by most clinical groups. If possible, an FBC to assess Hb and platelet count, and clothing screen should be taken for laboratory assessment. Once coagulation failure has occurred, it is very difficult to stop obstetric haemorrhage by drug or surgical therapy alone.