Acta Anaesthesiol Scand 1992: 36: 31-37

Propofol anaesthesia versus paracervical blockade with alfentanil and midazolam sedation for outpatient abortion J. C. R~EDER Department of Anaesthesia, Bzrum Sykehus, Norway

Propofol anaesthesia was compared with paracervical blockade in a prospective, randomized study of 59 abortion patients. All the patients received alfentanil 0.01 mg/kg i.v. at the start of anaesthesia and were randomized into two groups. Group R (regional, 31 patients): midazolam 0.1 mg/kg i.v. and paracervical blockade with 2 x 10 ml of mepivacaine 20 mg/ml+ adrenaline 0.005 mg/ml. Group G (general, 28 patients): propofol 2.0 mg/kg i.v. induction and 75% nitrous oxide in oxygen spontaneous respiration. In 10 patients from the R-group venous blood samples were taken regularly for 30 min for serum concentration measurements (gas chromatography) of mepivacaine. Pain during induction of anaesthesia was remembered by 17% in Group G and 4% in Group R, whereas 8% in Group R remembered pain during the procedure compared with none in Group G. Of the patients in Group G, 25% had apnoea compared with none in Group R. In Group R the patients slept for 2.5 & 3.8 min (mean s.d.) after induction compared with 12 + 4.0 min in Group G. Except for a better p-deletion score 30 min after the procedure in Group G, there was no difference in recovery function between the groups. Of the patients in Group G, 67% experienced postoperative pain compared with 23% in Group R. Maximum serum mepivacaine concentration (Group R) was reached at 15-30 min, range I .5-5 pg/ml. Received 5 March, accepted for publication 19 M a y 1991

Key words: Abortion; alfentanil; mepivacaine serum concentration; midazolam; outpatient anesthesia; paracervical blockade; propofol; recovery function.

We have previously described general anaesthesia with propofol alfentanil + nitrous oxide as our preferred method for outpatient minor gynaecology (1). However, regional anaesthesia may be better from a theoretical point of view, in terms of less peroperative apnoea, less postoperative pain and nausea, and better recovery function. Some problems are encountered with regional anaesthesia: increased peroperative discomfort for the patients, lower turnover of patients in the operation unit, and toxicity of absorbed local anaesthetic drug. The need for sedative drugs to enable the patient to tolerate an abortion procedure under regional anaesthesia may interfere with rapid recovery (2). The use of sedative and analgesic drugs with a rapid elimination, such as midazolam and alfentanil, may diminish this problem. The present study was designed to address these questions in a prospective, randomized group comparative study.

+

MATERIAL AND METHODS The study was approved by the Ethical Committee of the hospital and performed according to the Helsinki I1 declaration. Eighty-eight consecutive abortion patients were asked to participate in the study;

21 refused and 8 were excluded as they did not fulfil the inclusion criteria. Fifty-nine patients participated in the study after giving informed written consent. Inclusion criteria were: patients due for a routine first trimester abortion procedure, weight 50-80 kg and ASA physical status class I or 11. All the patients were seen by the anaesthesiologist the week before the procedure. The patients were asked about: previous disease, incidence of headache and travel sickness, drug consumption, previous anaesthetic experience, smoking, coffee and alcohol drinking habits, education and present work, and anxiety before the procedure. The patients performed the p-deletion test (p-test) (3) and the Maddox-Wing test (4) (for description of tests, see below). The patients were admitted as outpatients after at least 9 h fasting at home. They were asked about the previous night’s sleep and performed the visual analogue scale test (VAS-test) (5). The first card in the amnesia test (A-test) was shown before premedication with midazolam 0.1 mg/kg i.m. The patients were transferred to the operating room after 45 min and randomly allocated to one of two groups. The investigators of postoperative patient function did not know the group to which the patients were allocated. Anaesthesia techniques Group R (regional anaesthesia, 31 patients): midazolam 0.1 mg/kg i.v. and alfentanil 0.01 mg/kg i.v. was given 1-2 min before application of paracervical blockade with 2 x 10 ml of mepivacaine 20 mg/ ml with adrenaline 0.005 mg/ml. The patients were breathing air spontaneously and assisted with oxygen by mask if arterial oxygen saturation dropped below 85% (finger pulse oximeter, Nellcor). Group G (general anaesthesia, 28 patients): alfentanil 0.01 mg/kg

32

J. C. REDER

i.v. 60 s before i.v. bolus injection of propofol2.0 mg/kg. The patients breathed 75% nitrous oxide in oxygen spontaneously by mask and were assisted if arterial oxygen saturation dropped below 85%. The same anaesthesiologist gave all the anaesthesia and did all the peroperative registrations. During the procedure ECG and pulse oximetry were monitored continuously. Blood pressure was recorded intermittently by automatic device (Dinamap). Patient discomfort or side-effects were noted, and by the end of the procedure an overall statement of anaesthesia quality (scale: good, medium, less than medium or bad) was issued by the gynaecologist and anaesthesiologist. In ten patients from the R-group blood samples were drawn from an antecubital vein at regular intervals for 30 min for serum concentration measurements of mepivacaine.

in Table 1. A new card was shown for 10 s each time and the patients were told to try to remember the motif. Each card had a single, simple motif (e.g. a banana, an orange, a flower, a butterfly). Three hours postoperatively the patients were asked to name the motifs they remembered and subsequently to pick out the cards they had seen before from a pack of 12 different cards. Amnesia time was defined as the time from the end of anaesthesia until the time of presentation of the last card the patient was unable to remember or recall.

Postoperative observation Immediately after the end of anaesthesia the patients were transferred to the recovery ward and observed for 3 h by a nurse who did not know to which group the patients belonged. Postoperative registrations and tests were performed in each patient as indicated in Table I. After 3 h postoperative observation the patients were discharged to their homes. They were instructed to have a person accompanying them and not to drive that day.

Muddox-Mng test (4):The change from baseline registration (e.g.

Tests Codperation score: The patients were tested at the times indicated in Table 1 for simple tasks of co-operation: a) Squeezing the hand: 0 = n o squeeze; 1 =weak squeeze; 2 =firm squeeze. b) Pointing at the tip of nose: O = no pointing; 1 =attempted, but unsuccessful pointing; 2 =successful pointing. c) Orientation in place: 0 = not orientated in place; 1 =orientated in place. d) Orientation in time: 0 =not orientated; 1 =orientated. e) Orientation in situation: 0 =not orientated; 1 =orientated. A total score of zero means no co-operation and 7 (=maximum) means all tasks correctly performed.

State of wakefulness score: The patients were evaluated at the times indicated in Table 1 for state of wakefulness, with a score from 1 to 6: 1 =comatose; 2 = sleeping, arouseable by a tactile stimulus, but not when spoken to; 3 =sleeping, arouseable when spoken to; 4 = sleepyldrowsy; 5 = awake, normal; 6 =awake, agitated. A-test: The patients were shown one out of six different picture cards throughout the pre- and post-operative period, at the times indicated

Table 1 Schedule for postoperative patient data registration: x =registration performed

60

30

Registration

15

Systolic BP Pulse rate Respiratory rate Co-operation score State of wakefulness score A-test P-test Maddox-Wing test Visual Analogue Scales (VAS) Side-effects Function tests

X

X

X

X

~

X

X

X

x

X

x x x

x x x

X

X

180

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X

120

x

x x x x x x

x x x x x

P-tcsf. A modified p-deletion test, as described by Dixon & Thornton (3), was used. The patients were shown a sheet of randomly written letters and told to delete with a pen all p's as fast and accurately as possible during a 3-min period. Score=total number of COTRC\\Y deleted p's.

preoperative consultation) of eye muscle divergence was registered.

Visual Analogue Scales (VAS) ( 5 ) : Six visual analogue scales of 100 mm between pairs of verbal extremes were used. The pairs were. happy - deeply depressed, fully awake - extremely tired, no anxiety - profound anxiety, no pain - extreme pain, no headache - extreme headache, no nausea - extreme nausea. Side-effects, drugs. Postoperative side-effects and need for analgesic or antiemetic drugs were recorded. The patients were specifically asked about headache, nausea, vomiting, blurred vision and pain. The patients were given a score of 1 for each registration of pain and a score of 1 for each administration of analgetics. The scores were added for each patient to a total pain score, minimum score = 0 and maximum score= 12. In the same way, a total nausea score was calculated. Function tcsts. At 120 and 180 min postoperatively the patients were encouraged to drink water, walk on the floor and to void.

Questionnaire. In a questionnaire the patients were asked 5 days after the procedure about discomfort and side-effects during the hospital stay, as well as side-effects during their travel home, at home in the evening, and the day after. They were asked about wakefulness in the evening after the anaesthesia and the level ofactivity the day after. They were asked about the performance of six everyday functions in the evening, and assigned a score from 0 to 6, score= 6 being ability to perform all six activities. They were asked to state the number of days before they felt perfectly normal after the procedure and the number of days they wanted sick leave. Assay Serum mepivacaine was determined by gas chromatography. To serum, 0.5 ml, was added: 0.1 ml internal standard (bupivacaine 5 pgglml), 4.0 ml n-hexan/diklormetan (4:l ) , 0.5 ml 0.1 M NaOH. After extraction and centrifugation, the organic phase was pipetted off and evaporated to dryness by air at 40°C. The residue was dissolved in 300 pI n-hexanlethano1 (9: I ) . A I-kl sample was injected onto a crosslinked methyl-silicon column (Hewlett-Packard). The injector and detector temperatures were 150 and 230°C, respectively. The carrier-gas (He) flow rate was 1 ml/min. NH, was added as ionization gas. Mepivacaine and bupivacaine were detected by a Finnigan T S Q 70 mass-spectrometer. The standard curve was constructured for serum mepivacaine between 0 and 8 pg/ml. SlufiFtics The Mann-Whitney test was used to evaluate differences between the two groups for non-parametric data, and Student's t-test for parametric data. The chi-square test was used when indicated in

33

PROPOFOL VERSUS PARACERVICAL BLOCKADE the tables. A P-value less than 0.05 was regarded as statistically significant.

RESULTS Fifty-nine patients were included in the study, no patients were excluded after inclusion. Nine patients did not answer the post-operative questionnaire. There was no difference in demographic and preoperative data between the groups (Table 2). Previous anaesthetic and gynaecological experience, smoking habits, alcohol consumption, and previous headache and nausea incidence were comparable (data not shown). The peroperative results are listed in Table 3. Patient discomfort was not severe and did not necessitate additional administration of drugs or change in anaesthetic procedure in any case (Table 3). There were no episodes of hypersalivation, hiccups, hypotension or bradycardia in any patient. Systolic blood pressure and pulse rate were significantly higher in the R-Group (Figs. 1, 2). In 9 out of 10 patients (group R ) maximum serum mepivacaine concentration was reached after 20-30 min, range 2-5 pg/ml (Fig. 3). In one patient a maximum mepivacaine concentration of 8 pg/ml was measured initially with subsequent rapid

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Table 2 Patient characteristics. Mean values in each group ( f s.d.)

Age (years) Weight (kg) ASA group 1/11 (n) Pre-anaesth. nightsleep (h) Premedication time (min)*

Group G general an. (n=28)

Group R regional an. (n=31)

23 f 4.8 60 f 9.2 25/3 5.5 k I .6 5 9 k 16

24 f 6.3 63+11 29/2 5.0 f 1.4 5 3 k 17

*Time from administration of prernedication to induction of anaesthesia.

Table 3 Anaesthesia data. Mean values f s.d. or Yo Group R Group G general an. regional an. (n=28) (n=31) Duration of anaesthesia (rnin)' 8.2+3.1 Duration of sleep (min) 12 f 4.0 Apnoea incidence (0,sat < 85% in > 30 s) 25% Patient discomfort' - during induction of anaesthesia - during cervical dilatation - during uterine curettage

50% 0 3%

10.5 f 2.7* 2.5 f 3.8** 0** 53% 58% * * 39% * *

I Time from start of anaesthesia induction to patient transfer to recovery. Chi-square test. *P