We aim to compare the postoperative analgesic and respiratory outcomes in patients receiving continuous bupivacaine infusion via bilateral erector spinae catheters versus preperitoneal catheters in upper abdominal surgeries.

Inclusion Criteria:

• ASA physical status I-II, weighing 50-90 Kg with Body Mass Index (BMI) 18.5- 29.9 kg/m2

Exclusion Criteria:

• ASA physical status ≥III, pregnancy, body mass index >30 kg/m2, preoperative opioid consumption, patient's refusal and contraindications of the use of spirometry or either of the truncal blocks under the study including; respiratory, cardiac, neurological, mental or coagulation disorders.