PROBLEM 1 - ANTINA

Background

Post-anaesthetic nausea and vomiting can be a real problem for some patients. The symptoms are believed to be related to age, sex, as well as factors such as obesity, motion sickness and prior history of post-anaesthetic nausea. A known anti-vomiting drug, Antina, was compared to a placebo in a randomized experiment to see if it could prevent post-operative nausea and vomiting.

Design

One hundred adult patients, booked for elective surgery, were eligible. (One was later excluded because of a technical problem.)

A history of previous post-operative nausea and vomiting, motion sickness or migraines was taken. Patients were randomized to receive an injection of antina or placebo 10 minutes after anaesthesia. Heart rate and blood pressure were recorded immediately before injection, and 1 and 5 minutes post-injection.

The occurrence of nausea and vomiting was determined in the recovery room. Each item was scored ** after receiving narcotics. Nausea was scored as present or absent; vomiting was rated on a 4- point scale: 0=no vomiting, 1=retching, 2=vomiting once, 3=vomiting more than once.

Questions:

1.	Are the groups similar at the start (i.e. after randomization)?

2.	Is there evidence of side effects, in terms of changes in heart rate or blood pressure?

3.	Does the drug work? That is, is there evidence that the two groups differ in nasuea and vomiting post - narcotics

IMPORTANT

For this problem, use SIMPLE summaries and graphical presentations of the data to address the questions. Do NOT use any other methods. In particular, in this assignment it is not necessary to do any statistical tests

Think about (a) the type of data each item represents; and (b) what methods of presentation will be the clearest and most informative for your question.

Antina Data

The data are in the EXCEL file ANTINA.XLS

VARIABLE	MISSING	DESCRIPTION

NUMBER	VALUE

1	-	ID number

2	-	treatment group:

1 = placebo 2 = antina

3	-	age

4	-	sex: 1 = female: 2 = male

5	-	height (cm)

6	-	weight (kg)

7	-	prior history post-op nausea*

8	-	motion sickness*

9	-	migraine*

10	999	Blood Pressure at 0 minutes

11	999	Blood Pressure at 1 minute

12	999	Blood pressure at 5 minutes

13	999	Heart Rate at 0 minutes

14	999	Heart Rate at 1 minute

15	999	Heart Rate at 5 minutes

16	9	post-narcotics nausea ,(0 = no; 1 = yes)

17	9	post narcotics vomiting level:

0 = none: 1 = retching:

2 = vomited once

3 = vomited more than once