Comparison of Intrathecal Dexmedetomidine Versus Fentanyl as Adjuvants to Bupivacaine on Post-operative Urinary Retention in Knee Joint Arthroscopic Surgeries

Comparison of Intrathecal Dexmedetomidine Versus Fentanyl as Adjuvants to Bupivacaine on Post-operative Urinary Retention in Knee Joint Arthroscopic Surgeries

Comparison of Intrathecal Dexmedetomidine Versus Fentanyl as Adjuvants to Bupivacaine on Post-operative Urinary Retention in Knee Joint Arthroscopic Surgeries

The aim of this study was to assess the effect of intrathecally injected 5 µg dexmedetomidine or 25 µg fentanyl as adjuvants to bupivacaine in low dose spinal anesthesia for unilateral arthroscopic knee surgeries, on post-operative urinary retention (POUR), time needed to reach sensory block at the tenth thoracic dermatome (T10), the maximum sensory level achieved, the onset of motor block, the intra-operative fluids given, the duration of sensory and motor blocks, time to micturition or insertion of an intermittent urinary catheter and the number of patients who needed an indwelling (Foley's) catheter. Seventy patients, ASA physical status I or II, from 21 to 50 years old, scheduled to undergo unilateral arthroscopic knee surgeries under spinal anesthesia, were randomly divided into two equal groups; the Bupivacaine- Dexmedetomidine group (BD) patients and the Bupivacaine-Fentanyl group (BF) patients.

In a 3 ml syringe, 5 µg dexmedetomidine was added to the 2 ml of 10 mg hyperbaric bupivacaine, to have a total volume of 2.5 ml for intrathecal spinal injection over 3 minute without barbotage

In a 3 ml syringe, 25 μg fentanyl was added to the 2 ml of 10 mg hyperbaric bupivacaine, to have a total volume of 2.5 ml for intrathecal spinal injection over 3 minute without barbotage

Ultrasound assessment of the urinary bladder volume was done at the 3rd post-operative hour, a bladder volume of >700 ml with no ability to void confirmed the presence of urinary retention

The time from completion of intrathecal injection of the study drug till loss of sensation to pin prick at T10 on the operative side, assessed every 2 minutes.

Sensory level assessment by loss of sensation to pinprick every 2 minutes, until the highest level had stabilized for four consecutive tests

The time from completion of intrathecal injection of the study drug till having a modified Bromage score = 1 or more

he time from completion of intrathecal injection of the study drug till regression to the third sacral dermatome (S3) level

The time from completion of intrathecal injection of the study drug till complete recovery of the motor function (MBS = 0), by asking the patient to flex the hip, knee and ankle joints, in the PACU, then every 15 minutes in the ward

The time from completion of intrathecal injection of the study drug till voiding or insertion of an in-out catheter

After 6 post-operative hours, if the patient wasn't able to void an indwelling (Foley's) catheter was then placed

Inclusion Criteria: ASA physical status I and II aged 21-50 years scheduled to undergo unilateral arthroscopic knee surgeries under spinal anesthesia Exclusion Criteria: Patients' refusal contraindications to spinal anesthesia patients with coagulopathy infection at the lumbar region pre-existing neurological deficits in the lower limbs known allergy to any of the study drugs urinary incontinence cysto-ureteric reflux patients with congestive heart failure patients with dysrhythmia patients with heart block diabetic patients patients on α2-adrenergic receptors antagonists calcium channel blockers