Comparison between the effects of intrathecal morphine versus intrathecal dexmedetomidine on analgesia and respiratory function, in open heart surgery.

Postoperative pulmonary dysfunction is a well-recognized complication of open-heart surgeries. About 25% of patients who don't present with any severe impaired cardiac function reported to have significant pulmonary dysfunction for at least one week after operation. Many mechanisms could be accused of this dysfunction as respiratory mechanics failure by diaphragmatic paresis or paralysis, pain and muscle guarding, lung atelectasis, drains discomfort, etc.

although pain is the major concern of patients, but sometimes it may not get the proper attention, pain in open heart surgery origins mainly from the surgical incision which is here a median sternotomy the most commonly used approach and the easiest access to the heart region, however median sternotomy may significantly impedes the pulmonary function by the resultant pain of this procedure and cause morbidity and mortality by itself

Inclusion Criteria:

- Cardiac patient scheduled for elective open heart valve replacement surgery.

Exclusion Criteria:

• • Patient refusal

  • Coagulation disorders
  • History of known allergy to the used drugs.
  • Combined procedures (e.gif combined with coronary artery bypass or aortic root surgeries).
  • If thoracotomy or min-sternotomy is planned for the surgery.
  • Re-do and emergency surgeries.
  • History of chronic chest diseases (COPD or IPF).
  • History of thoracotomy, pneumothorax, pneumomediastinum, phrenic nerve injury (as evident by the presence of paralysis of the ipsilateral hemidiaphragm when examined preoperatively).
  • Neuromuscular diseases.
  • Brain injuries.