Rationalization of Postoperative Pharmacologic Analgesic Therapy in Appendectomy Patients

 

 

 

 

 

 

 

 

Oliver S. Leyson, MD

Rodney Dofitas, MD, FPCS

Anita Ocampo-So, MD, DPBA, MHA, FPSP

Reynaldo O. Joson, MD, MHA, MHPEd, MS Surg

 

 

 

 

 

 

Abstract

Background: Practices in postoperative pharmacologic analgesic therapy are varied that there is a need to review them in the light of quality and cost consciousness in health care.  Objectives: To determine the median pain score in patients undergoing appendectomy and to determine whether diclofenac-paracetamol or diclofenac-mefenamic acid regimen, two inexpensive drug-regimens, could be sufficient for appendectomy patients.  Methods: Action research methodology with randomized controlled trial on 76 appendectomy patients, aged 15-45 years old with ASA score of I-II was carried out from May to September 2003.  All patients received diclofenac about three hours postoperatively and then oral paracetamol 500mg every 4 hours or oral mefenamic acid 500mg every 6 hours  for 48 hours.  Step-up regimen were provided for pain score greater than 6.  Overall median postoperative pain score was computed and median pain scores in the P and M groups were compared.  Results: The overall median pain score after diclofenac administration was 2 while that after 4 to 6 hours, first and second day postoperatively was 3, 2, and 0 respectively.  The overall median pain scores in the P and M groups were 3 and 1 respectively.  The median pain scores on the first and second day were 3 and 0 respectively in the P group while those in the M group were 1 and 0 respectively.  No step-up regimen was used in both groups.  Conclusion: The overall median post-appendectomy pain score was 2, categorized as mild pain.  Diclofenac-paracetamol regimen may be initially administered postoperatively in appendectomy patients.

 

Keywords: post-op pain, appendectomy, mefenamic acid, paracetamol

Introduction:

            After an operation that requires the services of an anesthesiologist, the postoperative pharmacologic analgesic therapy is usually prescribed by the anesthesiologist.  The types of analgesic drugs prescribed vary from one anesthesiologist to another and also from one patient to another.  The drugs ordered can be opiods, weak opiods, or non-opiods; parenteral or oral; expensive or inexpensive.  The approach can be preemptive or preventive; step-down or step-up.

            With quality health care improvement being a buzzword in the community coupled with cost-consciousness, there is a need to review the postoperative analgesic therapeutic practices and approaches, especially in the light of too much variations or lack of standardization.

            In Hospital X, prior to this action research study in 2003, there had been no guidelines in the postoperative analgesic therapy.  The usual practice has been for the anesthesiologists to prescribe analgesics to be used in the immediate postoperative period, particularly in the post-anesthetic care unit (PACU) and the surgeons to prescribe analgesics when the patients are in the wards.  The prescriptions and approaches varied widely from one anesthesiologist to another and from one surgeon to another.  The types of drugs that have been known to be prescribed prior this action research study are the following: nalbuphine, ketorolac, tramadol, cox-inhibitors, diclofenac, ibuprofen, mefenamic acid, and paracetamol.  In May, 2003, realizing the presence of variations and their impact on quality patient care and resource utilization, the Hospital X Department of Surgery decided to initiate action researches in collaboration with the Department of Anesthesiology in an attempt to rationalize and standardize the postoperative analgesic therapy starting with the more common operative procedures in general surgery, namely: thyroidectomy, mastectomy, cholecystectomy, and appendectomy.

            The concept and methodology of an action research was utilized (1,2), namely: analysis of the problems, research designs on how to solve the problems, implementation of action plan, and then evaluation of results of implementation.  After the analysis of problems which revealed variations in practices and approaches with no guidelines and which affected resource utilization, the following questions and premises were formulated by the staff of surgery and anesthesiology which served as the take-off points for the research designs on how to solve the problems:

            What is the usual pain intensity or pain score of patients undergoing a certain operative procedure?

            The presence of this information will facilitate decision-making on the type and approach of analgesic drugs to be prescribed.  In the Philippines, however, there are no published data on this topic.  Initial consensus gotten from the surgical and anesthesiologist staff showed mild to moderate pain.  Although this would still be validated in the action research, it was agreed to use this as a take-off point or basis for formulating and validating the type and approach of post-operative analgesic therapy to be used in the study.

            As to type and approach in postoperative analgesic therapy, the following consensus between the staff of surgery and anesthesiology were arrived at:

            2.1 The usual pain score will determine the type of analgesic drugs to be used in terms of strength or efficacy - mildly strong analgesics for mild pain; moderately strong analgesics for moderate pain; and strong analgesics for severe pain.

            2.2 The price will determine the type of analgesic drugs to be used for each category of postoperative pain according to severity – cheapest drugs

possible.

            2.3 Step-up approach will be used to be consistent with the initially accepted policies on using appropriate analgesics based on severity of pain and price.

            Since the consensus of the surgical and anesthesiologist staff showed mild to moderate pain for the four pilot procedures, a trial using diclofenac in the PACU and paracetamol and mefenamic acid in the surgical ward was done.  These drugs are known to be effective for mild to moderate pain and their prices are relatively low.

            With this background information, the specific objectives of the pilot project , thus, consisted of the following:

            1.  To measure qualitatively the post-operative pain of patients who underwent thyroidectomy, mastectomy, cholecystectomy, and appendectomy.

            2.  To determine the efficacy of paracetamol in controlling postoperative pain of patients who underwent thyroidectomy, mastectomy, cholecystectomy, and appendectomy.

            3.  To determine the efficacy of mefenamic acid in controlling postoperative pain of patients who underwent thyroidectomy, mastectomy, cholecystectomy, and appendectomy.

            4.  To compare the efficacy of paracetamol and mefenamic acid in controlling postoperative pain of patients who underwent thyroidectomy, mastectomy, cholecystectomy, and appendectomy so as to determine which drug should be initially prescribed in such patients.

            This paper will limit its report on the rationalization of postoperative pharmacologic analgesic therapy in appendectomy patients.

Methods:

            From May, 2003 to September, 2003, a randomized controlled trial was done 76 patients, aged 15 to 45 years old, with ASA score of I-II, who underwent emergency appendectomy.  All patients diagnosed to have  acute non perforative appendicitis and with a right lower  quadrant transverse incision were included in the study.    

Randomization was done using a table of random numbers.  All sets ending in even numbers were assigned to the Paracetamol group (P group) and all odd numbers to the Mefenamic Acid group (M group).

            Preoperatively, the numerical value scale of 0-10 used to assess pain was explained to the patient and then baseline score was taken. ( Appendix I)  About 3 hours postoperatively, all patients were given intravenous diclofenac sodium 75 mg at the PACU and about six hours later, at the surgical ward, patients in the P group were given oral paracetamol 500 mg every 4 hours while those in the M group was given oral mefenamic acid 500 mg every 6 hours.

            Numerical pain score was assessed and recorded before any drug administration in the surgical ward, at interval of 4 hours for patients in the P group and 6 hours for those in the M group (Appendix 1).  Repeated pain assessment was done up to 48 hours postoperatively.  If the pain score was greater than 6, a step-up regimen would be given which consisted of oral mefenamic acid, 500 mg every 6 hours, for the patients in the P group and oral tramadol, 50 mg every 8 hours, for those in the M group.

            At the end of the accrual of patients, the following were computed and determined:

            1.  Overall median pain scores 4 to 6 hours after parenteral diclofenac sodium administration at the PACU, first and second day postoperatively regardless of type of oral analgesics given.

            2.  Overall median pain scores during the first 48 hours postoperatively in the P and M group and median pain scores in the first and second day post-op in the P and M group.

            3.  Presence of step-up regimen in the P and M groups.

 Results:

            For the whole subject population, the age ranged from 15 to 45 years old with 48 males and 28 females with the total of 76 patient.   In the P group, the age ranged from 15 to 45 years old with 25 males and 13 females whereas in the M group, the age ranged from 15 to 45 years old with 23 males and 15 females. (Table 1)

            The overall median pain score was 2 (Table 2).  It was 3, 4 to 6 hours after administration of diclofenac sodium; 2, first day post-op; and 0, second day post-op.

            The median pain scores in the first 48 hours post-op in the P group was 3 (Table 3)  while that in the M group was 1 (Table 4).  The median pain scores in the first day post-op in the P and M group were 3 and 1 respectively while those in the second day post-op were 0 and 0 respectively (Tables 3 and 4, Fig. 1 to 3).

            There was no step-up regimen used in both groups.

 

Discussion:

            In the light of quality and cost consciousness in health care, review and rationalization of health practices, especially those with too much variations, are in order.

            Postoperative pharmacologic analgesic therapy is fraught with too much variations with tendency towards expensive prescription, especially with the increasing popularity of cox-2-inhibitors which have now superceded that of nalbuphine.  The mainstay in postoperative pain control are still the paracetamol and non-steroidal analgesics (3 -4).

            An optimal and quality postoperative pharmacologic analgesic therapy is primarily a rationalized and secondarily an individualized regimen.  The most important quality parameter for a rationalized regimen is an appropriate prescription guided by the average postoperative pain severity or score of an operative procedure, such as mild analgesics for mild pain and strong analgesics for severe pain, and in consideration of the risks and cost of the drugs.  The quality parameter for an individualized regimen is the presence of provisions for adjustment in the data-based practice guidelines to suit the need of an individual patient in terms of step-up or step-down regimen of analgesics and in consideration of presence of risks for side effects and adverse reactions such as history of allergy and presence of co-morbid conditions.

            The present study attempted to rationalize and individualize a regimen of postoperative analgesic therapy for appendectomy patients in Hospital X.

            Since there are no published local studies or even international studies on the usual pain severity or score after an appendectomy, hypotheses were initially made based on experience of the senior authors and these hypotheses subsequently tested.  For reasons stated in the introduction, diclofenac-paracetamol and diclofenac-mefenamic acid regimens were used for the investigations.  For the use of step-up approach, this conforms to the recommendations of specialists in postoperative pain control (5) as well as to the philosophy behind the cancer pain control approach of WHO (6).

            This validation study has shown that the median pain severity for appendectomy patients in the Hospital X setting is mild.  With this mild pain severity, mildly strong analgesic regimen can be and should be used at least initially.  Room for individualization will come in for use of stronger analgesic when the pain threshold of the patient is assessed to be low preoperatively.  If the cost is considered in the choice of regimen, then the diclofenac-paracetamol regimen would be recommended.  The expense for a diclofenac-paracetamol regimen would amount only to PhP 134.40 in 48 hours postoperative compared to PhP 271.80 for a diclofenac-mefenamic regimen (Appendix II).  As an added comparison, for a nalbuphine-cox-2-inhibitor regimen (50 mg every 6 hours), which is lately commonly prescribed, the expense would amount to PhP 339.00 in 48 hours postoperatively.

            Whether the findings in the present study will be applicable to other settings, such as in a private setting, patients with different pain threshold and surgeons with different operative technique, is not known but can be and should be validated.  The median pain score may be high in a private setting where average pain threshold may be low.  The median pain score in this study is on the low side.  The authors do not know whether the preoperative counseling on pain control or the usually high pain threshold of patients in the lower income group or both had an effect on the postoperative pain score.  Studies have shown that preoperative counseling and patient’s expectation and satisfaction have an influence on the degree of postoperative pain severity (6).

            The value of this study in a tertiary city government hospital like Hospital X is that a rationalized postoperative pharmacologic analgesic therapy will lead to a standardized management with rooms for individualization and this rationalized and standardized management will in turn prevent confusion among the surgical, anesthesiologist, and nursing staff; minimize hospital and patient expenses; and serve as a guide in estimating hospital and patient budgeting for postoperative pain control expenses.

            The authors plan to institutionalize the findings of this study by incorporating them into a standard policy and procedures in the postoperative pain management of patients handled by the Departments of Surgery and Anesthesiology.  Constant monitoring, review, and validation of the policy and procedures will be done after this study as part of oversight and continual improvement in the ever changing setting in the hospital as well as in the rapidly increasing body of scientific information on postoperative pain control.

 

 

References

  1. Cohen L, Manion L. Research Methods in Education. London, Croom Helm, 1980; 31(2), 285-313.
  2. Marguiles N. Managing change in health care organization. Medical care, 1977; 15:693-704.
  3. White PF. The role of non-opioid analgesic techniques in the management of pain after ambulatory surgery. Anesth Analg 2002; 94:577-85.
  4. Siddik S, Aouad M, Jalbout M. Diclofenac and/or paracetamol for postoperative pain management after cesarean delivery in patients receiving patient controlled analgesia. Regional Anesthesia and Pain Management 2001; 26 (4) 310-5.
  5. PROSPECT - procedure specific postoperative pain management.

http://www.postoppain.org

  1. Anonymous WHO’s Pain Ladder URL: http://www.who.int/cancer/palliative/painladder/en
  2. Svensson I. Influence of expectation and actual pain experiences on satisfaction with post operative pain management, European Journal On Pain, 2001; 5(2): 125-33.

 

 

 

Appendix I

Numeric Pain Scale

Instructions:  Choose a number between 0 and 10 reflecting how severe your pain is at this moment.

(No pain)   0     1     2     3     4     5     6     7     8     9     10   (Worst possible pain)

 

Step-up Regimen

P Group :  Paracetamol 500 mg q4 PO                             Mefenamic acid 500 mg q6 PO

            If still with pain with Mefenamic acid                       Tramadol 50 mg q8 PO

 

M Group :  Mefenamic acid 500 mg q6 PO                       Tramadol 50 mg q8 PO

 

 

 

 

 

Appendix II

Comparative price list of different analgesics now commonly being used in the postoperative pain control in the Philippines.

 

Oral (PhP)

Parenteral (PhP)

Paracetamol

500mg    2.45

 

Mefenamic Acid

500mg    20.85

 

Diclofenac Na

50mg      7.90

100mg     15.00

75 mg  105.00

Ibuprofen

200mg     7.00

 

Ketorolac

 

30mg     111.00

Nalbuphine

 

10mg     113.00

Tramadol

50mg     27.00

100mg    68.25

50mg    112.25

100mg     154.00

CoX-2 inhibitor

      Brand 1

 

       Brand 2

 

12.5mg    43.50

25mg    43.50

50mg    56.50

100mg    40.00

 

Morphine tab

10mg   9.40

20mg    16.25

30mg    21.00

 

            *Prices quoted by the largest drugstore in Metro Manila.

Table 1.  Age and sex distribution of patients who underwent appendectomy.

 

P Group

M Group

Age

Male

Female

Male

Female

15-19

2

5

8

8

20-24

11

4

3

3

25-29

7

1

4

1

30-34

1

0

5

1

35-39

1

0

2

1

40-45

2

3

2

1

Total

24

13

24

15

 

 

 

 

 

 

 

 

Table 2. Summarizing table of median pain scores, overall and in specific group,(range)

 

P group

M group

 

Overall median pain score (range)

 

 

2(0-6)

Overall median pain score 4 to 6 hours after diclofenac sodium injection (range)

 

 

3(0-6)

Overall median pain score 24 hours postop (range)

 

 

2(1-5)

Overall median pain score 48 hours postop (range)

 

 

0(0-3)

Median pain score in the P group (range)

3(0-6)

 

 

Median pain score in the M group (range)

 

1(0-6)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 3.  Median pain score for P group.

 

Hours Post-op

Median Pain Score

4

3

8

3

12

3

16

3

20

3

24

3

28

3

32

3

36

2

40

1

44

1

48

0

 

 

 

 

 

 

 

 

 

Table 4.  Median pain score for M group.

 

Hours Post-op

Median Pain Score

6

3

12

2

18

2

24

1

30

1

36

1

42

1

48

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 1  Graph showing median pain score for P group.

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

Fig. 2  Graph showing median pain score for M group.

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

Fig. 3  Graph showing median pain score for P and M groups.

  

 


 

                                                                                                P Group

                                                                                                                                M Group