Our aim will be to compare the analgesic efficacy and safety of ketamine and magnesium sulphate as adjuvants to levobupivacaine in erector spinae plane block in modified radical mastectomy.

The participating females will be randomly allocated using computer generated randomizer program (http://www.randomizer.org) into one of 3 groups.

Group (C) / (I): 20 patients (control group):

Patient will receive 20 ml 0.25% levobupivacaine into interfascial plane below erector spinae muscle at level of T5 and T7.

Group (K) / (II): 20 patients (Ketamine group):

Patient will receive 20ml 0.25% levobupivacaine as above + 2 mg /kg ketamine.

Group (M) / (III): 20 patients (magnesium sulphate group):

Patient will receive 20ml 0.25% levobupivacaine as above + 2mg/kg MgSo4.

Study protocol:

Premedication will be given, after complete fasting hours after applying standard monitors (noninvasive blood pressure, pulse oximetery. ECG, temp, and capnography), an intravenous cannula will be placed and secured in the opposite side to surgery.

Ultrasound guided Erector spinae plane (ESP) block will be given with patient in sitting position depending on surgical site (lt. or Rt.) ESP block will be given using high frequency linear u/s transducer, the probe is placed in longitudinal orientation lateral to thoracic fifth and seventh spinous process, then Trapezious m., Rhomboideus major muscle, and erector spinae muscle, are identified from surface, we will deposite 20 ml of 0.25% levobupivacairen into interfacial plane below erector spinae muscle.

General anesthesia will be induced with lμg/kg fentanyl, 2mg/kg propofol, 0.5 mg/kg atracurium inhalational anesthesia (isoflurane or sevoflurane)

1gm paracetamol after induction No other narcotic, analgesic or sedative will be administrated during operative period.

Standard monitor (MABP, HR , SaO2 & EtCo2) will be observed and recorded every 30 min till end of surgery Post-operative ; the patient will be transferred to the post anesthesia care unit (PACU). In PACU the following data included heart rate, mean blood pressure, respiratory rate and oxygen saturation and VAS scores (at rest and after movement in the form of abduction of ipsilateral arm ) at baseline,2,4,6,12,24 and 48 hours post-operatively to evaluate acute pain will be observed and recorded. The attending anesthesiologist, surgeon and the data collecting personal will be unaware of the patient assignment.

Rescue post-operative analgesia in the form of morphine Patient controlled analgesia (PCA ) with an initial bolus of 0.1 mg/ kg morphine once pain is expressed followed by 1mg bolus with a locked period of 15 minutes with no back ground infusion allowed. The time to first request of analgesia and the total analgesic consumption in the 1st 48 hour will be observed and recorded. Postoperative adverse effects will be observed and treated

Inclusion Criteria:

• Age of 18 - 60 years.
• ASA grade I - II.

Exclusion Criteria:

• Patient refusal. known allergy to the study drugs skin infection at site of needle puncture significant organ dysfunction Coagulopathy drug or alcohol abuse psychiatric illness that would interfere with perception and assessment of pain.