Satisfactory Analgesia Minimal Emesis in Day Surgeries
Satisfactory Analgesia Minimal Emesis in Day Surgeries
Currently nearly 70% or more surgeries are being done as ambulatory (day care) procedures as
 they offer significant benefit to the patients as well as to the hospitals. Inadequate pain
 relief (30%-40%) and nausea-vomiting form the leading factors affecting the quality of care
 and hence its efficiency. Opioids form the primary modality to treat moderate to severe pain,
 but can also cause significant nausea-vomiting and other side effects. Although hydromorphone
 is five times more potent than morphine, in equianalgesic doses they both could provide
 similar pain relief. They both exert no ceiling effect for their analgesia, and hence
 incomplete or inadequate analgesia is related to the appearance of side effects. In this
 study the investigators shall assess the proportion of patients who satisfy the outcome of
 'satisfactory analgesia with minimal nausea-vomiting' in ambulatory surgeries, assessed at 2
 hours after surgery. Patients would be randomized to receive either morphine or hydromorphone
 in the surgical recovery area. All personnel involved with the study would be blinded. The
 investigators will also look to assess the time to discharge and other side effects. This
 will help to choose the better drug, thereby improving pain relief and side effects, and also
 the efficiency of health care delivery.
There has been an exponential increase in the number of day case surgical procedures also
 called as ambulatory surgeries (AS), over the last 2 years.(1) Currently around 70% of
 procedures are being done as AS, with known benefits to patients and hospitals.(2) Its
 efficiency and cost effectiveness depends upon its organization and delivery of services.
 Pain and PONV are recognized as the leading factors affecting the quality of services
 delivered under AS,(1,3) and they affect the recovery, discharge, and overall satisfaction of
 patients.(4,5) According to literature, postsurgical pain could be inadequately treated in
 30%-60% of patients and 30%-40% of AS patients suffer from significant PONV.(3,6,7) It is
 estimated that a single episode of PONV can prolong the PACU stay by 25 mins,(8) and patients
 rate PONV to be the most undesirable outcome associated with anesthesia.(4) Despite the
 increasing use of non-opioid analgesics, opioid analgesics have remained the primary modality
 in moderate to severe pain.(7) They cause several side effects such as drowsiness, sedation,
 PONV, itching and respiratory depression. Appropriate selection of opioid medications becomes
 significantly important to deliver safe and effective analgesia with minimal side effects.
 Although M has been the most commonly used medication, HM is also being increasingly used.(9)
 We do not yet know whether HM is more effective than M in AS patients. Both M and HM exert no
 ceiling effect for their analgesia, and by this nature incomplete or inadequate analgesia is
 related to the appearance of side effects.(10) Hence clinical effectiveness of opioids,
 relative to each other, is reflected not just by satisfactory analgesia, but by a combination
 of 'satisfactory analgesia with limited side effects'. Clinical observation suggests that HM
 is clinically better by providing superior or equivalent analgesia with decreased side
 effects.(9) HM is a semi-synthetic morphine derivative that differs from M in its position 6
 of the benzol ring, where it has a keto-group instead of a hydroxy group, making it 5-10
 times more potent and enhances its distribution to cerebral tissues, making for easier
 titration.(9) The t1/2 Ke0 (transfer life from plasma to effect site) is 1.6hr - 4 hr for M,
 compared to 18-38 min for HM.(9,10) It is observed that health care providers may be willing
 to provide higher dose of HM compared to M in EMU, as its actual quantity of drug is much
 smaller and therefore appears to cause less concern.(12, 13) Our literature review showed
 that there are no previous studies comparing these 2 medications in AS patients. The lone
 systematic review compared various acute and chronic pain studies, in various routes of drug
 administration.(9) Of the 11 studies identified; only 4 were done in acute pain
 settings.(13-16) Two of them were done by the same author in ER settings. Chang et al noted
 that HM reduced the mean pain scores by 1.3 units [95% CI= (-2.2 to -0.5)] compared to M in
 198 adults treated in ER.(12,13). However it did not show much difference in geriatric
 population.14 In perioperative settings, Hong et al studied the difference in nausea between
 the 2 medications in 50 patients using PCA and found no difference.(15) Rapp et al studied
 various effects between the 2 medications in 61 surgical patients using PCA. There is not
 much clarity about their primary outcome; however they found the effects to be similar.(16)
 Both these studies had smaller sample sizes. The meta-analysis performed demonstrated that
 the HM does provide better analgesia than M, with a small effect size; Cohen's d=0.266
 (p=0.012).(9) Looked at acute pain alone it was statistically significant (p=0.006), compared
 to chronic pain (p=0.889). It was noted that that there is a definite lack of comparative
 studies between them in surgical settings.
Inclusion Criteria:

 -  ambulatory surgeries producing at least moderate pain-such as cholecystectomy,
 appendicectomy, ovarian cystectomy, inguinal hernia repair, abdominal wall hernias

 -  ability to communicate in English.

 Exclusion Criteria:

 -  allergy to M or HM

 -  patient on regular chronic opioid medication

 -  patient uncontrolled systemic disease

 -  severe obesity with a BMI >35

 -  significant psychological impairment

 -  history of drug addiction or dependence

 -  any planned regional or nerve block other than local anesthesia infiltration patients
 with confirmed sleep apnea

 -  emergency surgeries and urological surgeries