0306-4603 791020,.On55M?.OwO
ESTIMATING BLOOD ALCOHOL CONCENTRATION: TWO COMPUTER PROGRAMS AND THEIR APPLICATIONS IN THERAPY AND RESEARCH DANIEL
B. MATTHEWS University
and
WILLIAM
R.
MILLER*
of New Mexico
Abstract-Two computer programs for estimating blood alcohol concentration (BAC) are described. BACTAB generates individualized tables for BAC estimation based upon a client’s sex, body weight, amount of consumption, and drinking rate. ALCOMP convertes data from client self-monitoring cards into weekly summary statistics and plots a table for each individual client showing BAC estimates at each half-hour interval throughout the week. Various applications of these programs in controlled drinking therapies and in treatment outcome research are discussed.
Blood alcohol concentration (BAC) is an important variable in alcohol education, treatment, and research. It reflects the level of impact of drinking upon the body, the degree of intoxication, and the probable behavioral effects more accurately than does the absolute volume of alcohol consumed. The advent of controlled drinking therapies has focused new attention on BAC both as an outcome measure and as a basic concept in therapeutic interventions. Lovibond & Caddy (Lovibond & Caddy, 1970; Caddy & Lovibond, 1976) introduced BAC discrimination training as a treatment method for persons seeking to control their drinking. Their clients consumed alcohol in a simulated bar setting, stopping after each drink for BAC feedback from a breath analyzer. An internal cue procedure was used whereby clients were instructed to attend to proprioceptive cues associated with rising BAC. Lovibond and Caddy reported that their clients were able to estimate BAC with an accuracy of + 10 rng% after a few training sessions. Using this procedure in combination with aversion therapy and self-control training, they achieved and replicated a success rate of 75% for establishing controlled drinking in problem drinkers. Subsequent studies have generally supported their findings (Bois & Vogel-Sprott, 1974; Silverstein et al., 1974; Vogler et al., 1975, 1977a,b). An alternative method for teaching clients to estimate BAC is through the use of external cues. Various tables and instruments have been devised to permit estimation of BAC from the amount of alcohol consumed, time since consumption, and body weight (e.g. Compton & Vogler, 1975; Miller & Muiioz, 1976; Rutgers Center of Alcohol Studies, 1972). Huber et al. (1976) compared the effectiveness of three BAC training procedures: (a) internal cue training only, (b) external cue training only, and (c) training in both internal and external cue procedures. Their moderate drinking subjects in all groups learned to discriminate BAC to within f 10 mg%, with no significant differences among training procedures. Comparing alternative treatment methods for problem drinkers, Vogler and his colleagues (1977a,b) found no significant difference in effectiveness between an extensive multimodal program that included internal cue training and a basic alcohol education program that incorporated external cue training. In five separate outcome studies employing external cue training within a multimodal approach, Miller and his colleagues (Miller, 1977, 1978; Miller et al., 1976, 1977; Miller & Taylor, 1978a, 1978b) have found follow-up improvement rates in excess of 70%. These studies suggest that external cue training, which does not require use of expensive equipment or in-session drinking, may be the more cost-effective procedure. * Requests for reprints should be sent to William R. Miller, Department of Psychology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A. Documentation is also available for both programs described in this report. 55
56
DANIEL B. MATTHEWSand WILLIAMR. MILLER
The two computer programs described below were developed as aids in the external cue training of BAC discrimination in problem drinkers. BACTAB is a program that provides each client with an individualized BAC estimation table, taking into account both body weight and differences between males and females with regard to the volume distribution of ethanol. ALCOMP was designed to convert clients’ drink-by-drink selfmonitoring cards into weekly summary data usable in outcome research, and to give clients an hour-by-hour estimation of their BAC level throughout the recorded week, arduous and time-consuming tasks by hand calculation. Both programs are written in FORTRAN and are available in interactive or batch processing versions compatible with the IBM 360 computer. BACTAB
Although published tables of BAC are available, they tend to provide data only for a standard weight individual or for a few gross weight categories (e.g. Miller & Muiioz, 1976). Most tables also fail to take into account sex differences in volume distribution of alcohol (Jones & Jones, 1976; Ray, 1972) or to standardize what counts as a “drink.” Finally, tables designed for a range of individuals of necessity reflect a relatively small number of drinks and hours of drinking. One excellent slide rule device overcomes some of these problems, but our clients have found this instrument complicated or inconvenient to use (Rutgers Center, 1972). BACTAB is designed to provide clients or students with BAC tables individualized by both weight and sex. It is based on a standard “drink” unit and provides BAC estimates over a wide range of alcohol consumption and time values.
The input data for BACTAB consist simply of the individual’s code number, weight and sex. A batch processing version of the program permits preparation of multiple tables in a single run, as for a class. The output from BACTAB is a table that gives BAC estimates for up to 25 drinks and for periods of drinking up to 10 hr. A “drink” is defined as the amount of any beverage containing 0.50 oz. (15 ml) of ethanol (Miller, 1977, 1978). The computation of BAC per ounce of ethanol ingested is a simple constant divided by the person’s weight in pounds. Different sources have used various constants. The data reported by Ray (1972) are used in BACTAB, the constants being 7.5 for males and 9.0 for females. Users could easily substitute a different constant, such as the 7.2 figure derived from the Alto-Calculator slide rule (Rutgers Center, 1972). To estimate BAC at a given point in time it is further necessary to account for the amount of alcohol metabolized since consumption. Metabolism rates show substantial individual differences (Kalant, 1971; Lelbach, 1974) and an average figure of 16 mg% per hr has been used in BACTAB. If the individual’s personal metabolism rate has been determined this figure could be substituted. A sample output for a 120lb female is shown in Table 1. Applications of BACTAB
Few problem drinkers have more than a cursory understanding of BAC and its relationship to intoxication, behavioral and physiological manifestations, and legal sanctions. Societal lore suggests many mythical methods for decreasing alcohol’s effects or for accelerating alcohol metabolism. Few drinkers understand that tolerance to alcohol is more behavioral than metabolic. Those who believe themselves to have high metabolic tolerance may disregard warnings relating alcohol consumption to physical dangers or driving safety, assuming personal immunity to these contingencies. Clear education about what does and does not affect BAC is thus an important first step in alcohol education. BACTAB may be used early in treatment to assist clients in setting concrete goals or limits for their drinking. The table should be accompanied by an explanation of
Estimating Table
No. of
Drinks (sets)
1. Blood
1 2 3 4 5 6 7 8 9 10 I1 I2 I3 14 IS 16 I7 18 I9 20 21 22 23 24 25
alcohol
concentration
0
1
2
031 074 111 148 185 222 259 296 333 370 407 444 481 518 555 592 629 666 703 740 777 814 851 888 925
021 058 095 132 169 206 243 280 317 354 391 428 465 502 539 576 613 650 687 724 761 798 835 872 909
005 042 079 II6 I53 190 227 264 301 338 375 412 449 486 523 560 597 634 671 708 745 782 819 856 893
blood
as a function Client 3
of drinks
no. 2468 Female: 4 5
ooo
ooo
026 063 100 137 174 211 248 285 322 359 396 433 470 507 544 581 618 655 692 729 766 803 840 877
010 047 084 I21 I58 195 232 269 306 343 380 417 454 491 528 565 602 639 616 713 750 787 824 861
51
alcohol consumed 120lbs 6
and time taken
7
ooo ooo
ooo
ooo
031 068 I05 142 179 216 253 290 327 364 401 438 415 512 549 586 623 660 697 734 771 808 845
015 052 089 126 163 200 237 274 311 348 385 422 459 496 533 570 607 644 681 718 755 792 829
036 073 110 147 I84 221 258 295 332 369 406 443 480 517 554 591 628 665 702 739 776 813
ooo
ooo ooo
8
to consume
9
ooo ooo
ooo ooo
020 057 094 131 168 205 242 279 316 353 390 427 464 501 538 575 612 649 686 723 760 797
004 041 018 II5 I52 I89 226 263 300 337 374 411 448 485 522 559 596 633 670 701 744 781
ooo
ooo
IO
ooo ooo ooo ooo 025 062 099 136 173 210 247 284 321 358 395 432 469 506 543 580 617 654 691 728 765
the “one drink” unit and a table or discussion of the behavioral and physical effects to be expected at various BAC levels. Within this context a client can select a BAC level as an upper limit that he or she chooses not to exceed. Miller & Muiioz (1976) have recommended two types of limits: a regular limit that represents a ceiling for the average drinking day (most applicable with steady drinkers) and an absolute limit that provides a boundary for any drinking occasion. (We recommend that clients select these limits with regard to the effects of BAC, not by deciding desired consumption level and then finding the corresponding BAC value.) Having set these limits, the client can then use a BACTAB table to determine the number and spacing of drinks required to remain within them. For both students and clients BACTAB provides individualized education regarding the relationship between alcohol consumption and blood alcohol. Students may calculate the approximate number of drinks required to reach important levels such as (a) impairment of judgment, (b) legal intoxication, (c) unconsciousness, and (d) lethal dose. An interviewer who obtains a detailed account of current drinking pattern can also use BACTAB to obtain an estimate of the peak BAC reached by the interviewee during an average drinking week, a statistic useful both in assessment and in outcome research. ALCOMP
ALCOMP was written to perform more complicated computations useful in controlled drinking therapies and research. The input data for ALCOMP are derived from daily self-monitoring cards such as those used in many treatment programs (e.g. Miller & Muiioz, 1976; Sobell & Sobell, 1973). The output provides daily and weekly summary statistics and a table of BAC estimates for the data week. Program
The input to ALCOMP consists of client identification (code number, sex, weight, BAC limit chosen) and dates to which the data correspond, followed by an entry for each drink consumed during all days specified. A single day’s data include the time, amount, and alcohol concentration for each drink, followed by an entry signalling the
58
DANIEL B. MATTHEWS and WILLIAM R. MILLER
end of the data day. Entries are coded for convenience; e.g. 1.5 oz of 80 proof (40%) vodka consumed at 11:30 a.m. is coded as: 11, 30, 1.5, 40. The program echoes each entry in prose to verify accuracy of coding, and translates the drink into Standard Ethanol Content units (SECs) (Miller, 1978); e.g. 11:30 a.m.-l.5 oz, 40.0% 1.2 sets. Output is in three parts. The first section provides weekly and daily summary data. Table 2 is a sample week’s output for a 150 lb male client whose selected BAC limit was 50 mg”/;;. The second part of the output, also shown in Table 2, provides daily statistics for maximum BAC, time of BAC peak, SECs consumed, and time intervals during which the BAC limit and a standard level of 80mg% were exceeded. A third (optional) section of output is a table of estimated BAC at every half hour of every day for the data week. Sample output data for the same client are shown in Table 3. Hours prior to 4:30 p.m. (16.5) have been omitted because biood alcohol was estimated to be zero during these hours. The estimation procedures are identical to those for BACTAB, except that alcohol is assumed to enter the system 12 min after the drink is begun, allowing a standard interval for consumption and absorption. Applications
of ALCOMP
As a therapeutic tool, ALCOMP provides detailed feedback regarding client progress. From summary data the individual can obtain various indices of drinking in excess of goals. Small but significant changes in drinking can be detected and lend themselves to weekly graphing. Of special interest to clients are the total sets (consumption), maximum BAC, and total time over selected BAC goal, all good indicators of progress. The BAC estimate table allows a client to examine.factors such as the impact of various kinds of drinks, the compounding effects of drinks as a function of spacing, and the length of time required to metabolize alcohol. Hand calculation of such data is arduous if not impossible. Potential applications of ALCOMP in treatment outcome research are straightforward. The summary statistics provide a range of useful dependent variables on an ongoing basis. In addition to the absolute outcome data provided by pre/post measures, these weekly and daily data permit examination of the rate of progress and the relative
Table
2. Summary
Times over 80
Mon 27 0.044
for client
1357
6 2
Drinking days (DD) Days over 050 mg”,, Days over 080 mg”,, Days five or more sets Total sets Sets, DD Time over 050-week Time over 80-week Max bat for week Time and day of max Max bac/DD Day,‘Date High bat Time of High bat Sets consumed Times over goal
data
0
21.6 3.6 3.7 0.6 0.087 Fri 18.2 0.053 Tue 28 0.046
Wed 29 0.000
Thu 30 0.055
Fri 31 0.087
Sat 1 0.047
Sun 2 0.038
19.7
18.7
0.0
20.3
18.2
18.7
18.7
3.6
3.7
0.0
3.6
4.8
3.9
1.9
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
19.2 19.2 20.3 20.5
16.7 17.0 17.3 20.5
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
17.6 17.8 18.2 18.6
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
Estimating Table
16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0 20.5 21.0 21.5 22.0 22.5 23.0 23.5 24.0
3. BAC estimates
blood
59
alcohol
as a function
of time for client
1357
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat I
Sun 2
000 000 000 000 018 034 026 039 031 023 037 029 021 013 005 000
000 000 018 034 026 042 034 026 018 010 002 015 007 000 000 000
000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000
000 000 000 000 042 034 046 038 051 043 035 027 019 011 003 000
037 050 064 077 083 075 067 059 051 043 035 027 019 011 003 000
000 000 018 034 026 043 035 027 019 011 003 000 023 015 007 000
000 000 Oc@ 000 018 034 026 018 010 002 000 000 000 000 000 000
impact of program components on drinking dimensions through repeated measures analysis of variance and time series analysis.
techniques
such
as
DISCUSSION
Both BACTAB and ALCOMP have been employed in two treatment outcome studies involving more than 100 clients (Miller & Taylor, 1978a, 1978b). Therapists and research assistants have used the programs readily after brief instruction, and clients have responded favorably to this individualized form of feedback. These programs may also have preventive applications. BACTAB tables have been used as instructional aids in classes at the University of New Mexico, and the program has been made anonymously available to all users of our computing system. Although BAC computations are based upon the best available data, it is likely that changes in the basic formulae will be warranted as future data become available. Compton & Vogler (1975) have reported considerable variability in accuracy of BAC estimates from the Alto-Calculator. This variability may be reduced by including as predictor variables other factors influencing BAC; e.g. age, race, drinking history, liver function data, recent food consumption, emotional state. Data are needed regarding the relationship between such variables and BAC as measured by actual blood or breath samples. Such data may provide a basis for modifying the constants or calculation procedures now employed in BACTAB and ALCOMP. REFERENCES Bois, C. & Vogel-Sprott, M. Discrimination of low blood alcohol levels and self-titration skills in social drinkers. Quarterly Journal of Studieson Alcohol, 1974, 35, 8697. Caddy, G. R. & Lovibond, S. H. Self-regulation and discriminated aversive conditioning in the modification of alcoholics’ drinking behavior. Behacior Therap!, 1976, 7, 223-230. Compton, J. V. & Vogler. R. E. Validation of the Alto-calculator. Psychological Reports. 1975, 36, 977-978. Huber, H., Karlin, R. SC Nathan, P. E. Blood alcohol level discrimmation by nonalcoholics: The rote of internal and external cues. Journal of Studieson AIcohol, 1976, 37, 27-39. Kalant. H. Absorption diffusion, distribution, and elimination of ethanol: Effects on biological membranes. In B. Kissin & H. Begleiter (Eds), The Biology of Alcoholism Vol. I. New York: Plenum Press, 1971. Lelbach, W. K. Organic pathology related to volume and pattern of alcohol use. In R. J. Gibbins, Y. Israel, H. Kalant, R. E. Popham, W. S. Schmidt & R. G. Smart (Eds), Research Advances in Alcohol and Drug Problems Vol. I. New York: Wiley, 1974. Lovibond, S. H. & Caddy, G. Discriminated aversive control in the moderation of alcoholics’ drinking behavior. Behacior Therapy, 1970, 1, 437444. Miller, W. R. Behavioral self-control training in the treatment of problem drinkers. In R. B. Stuart (Ed.). Behacioral Self-Management: Strategies, Techniques and Outcomes. New York : Brunner/Mazel, 1977. Miller, W. R. Behavioral treatment of problem drinkers: A comparative outcome study of three controlled drinking therapies. Journal of Consulting and Clinical Psychology, 1978, 46, 74-86. . Miller, W. R. & Mmioz. R. F. How to Control Your Drinking. Englewood Cliffs. N.J.: Prentice-Hall, 1976. Miller, W. R. & Taylor, C. A. Relatice eflecticeness of bibliotherapy, indiaidual and group self-control training in the treatment of problem drinkers. Unpublished manuscript, University of New Mexico, 1978a.
DANIEL B. MATTHEWS and WILLIAM R. MILLER
60
Miller. W. R. & Taylor, C. A. Eoaluution CI/ u module program for problem drinkers. HEW/NlAAA grant No. I-R03-AA03450-01, University of New Mexico. 3978b. Miller. W. R.. Gribskov. C. & Mort& R. .Efli!ctirc)ne.ss of’ (1 se/$conrro/ munuul for problem drinkers with trnd wit!tout therapist c’onttrc’t. Unpublished manuscript. University of Oregon. 1976. Miller W. R.. Pechacek. T. F. & Hamburg. S. Group behavior thrrup~~ for probkem drinkers. Unpublished manuscript. Palo Alto Veterans Administration Hospital. 1977. Ray. 0. S. Drru/s. Sociczr!: um/ ffuruun Behurior. St. Louis: C. V. Mosby. 1972. Rutgers University Center of Alcohol Studies. A/co-Calculator: An Educational Instrument. New Brunswick. N.J.: Author. 1972. Silverstein. S. J., Nathan. P. E. & Taylor, H. A. Blood alcohol level estimation and controlled drinking by chronic alcoholics. Behurior Therapy. 1974, 5, l-15. Sobell. L. C. & Sobell. M. B. A self-feedback technique to monitor drinking behavior in alcoholics. Behaciour Rrseorch
Vogler,
_ Journul
Vogler.
and Therrrpy,
R. E.. Compton. of Conskting
R. E.. Weissbach.
and Thrrtrp~.
1973. II,
237-238.
J. V. & Weissbach. and Clinical
T. A. Integrated
Ps.vcho/oyy.
T. A. & Compton.
behavior
change
techniques
for alcohol
abuse.
for alcoholism.
1975, 43, 233-243.
J. V. Learning
techniques
Behucior
Resetrrch
1977a. 15. 3 I-38.
Vogler. R. E.. Weissbach. T. A., Compton, for problem drinkers in the community.
J. V. & Martin. Journal
G. T. Integrated
qf Consulting
and Clinical
behavior Psychology,
change techniques 1977b, 45, 267-279.
ESTIMATING BLOOD ALCOHOL CONCENTRATION: TWO COMPUTER PROGRAMS AND THEIR APPLICATIONS IN THERAPY AND RESEARCH DANIEL
B. MATTHEWS University
and
WILLIAM
R.
MILLER*
of New Mexico
Abstract-Two computer programs for estimating blood alcohol concentration (BAC) are described. BACTAB generates individualized tables for BAC estimation based upon a client’s sex, body weight, amount of consumption, and drinking rate. ALCOMP convertes data from client self-monitoring cards into weekly summary statistics and plots a table for each individual client showing BAC estimates at each half-hour interval throughout the week. Various applications of these programs in controlled drinking therapies and in treatment outcome research are discussed.
Blood alcohol concentration (BAC) is an important variable in alcohol education, treatment, and research. It reflects the level of impact of drinking upon the body, the degree of intoxication, and the probable behavioral effects more accurately than does the absolute volume of alcohol consumed. The advent of controlled drinking therapies has focused new attention on BAC both as an outcome measure and as a basic concept in therapeutic interventions. Lovibond & Caddy (Lovibond & Caddy, 1970; Caddy & Lovibond, 1976) introduced BAC discrimination training as a treatment method for persons seeking to control their drinking. Their clients consumed alcohol in a simulated bar setting, stopping after each drink for BAC feedback from a breath analyzer. An internal cue procedure was used whereby clients were instructed to attend to proprioceptive cues associated with rising BAC. Lovibond and Caddy reported that their clients were able to estimate BAC with an accuracy of + 10 rng% after a few training sessions. Using this procedure in combination with aversion therapy and self-control training, they achieved and replicated a success rate of 75% for establishing controlled drinking in problem drinkers. Subsequent studies have generally supported their findings (Bois & Vogel-Sprott, 1974; Silverstein et al., 1974; Vogler et al., 1975, 1977a,b). An alternative method for teaching clients to estimate BAC is through the use of external cues. Various tables and instruments have been devised to permit estimation of BAC from the amount of alcohol consumed, time since consumption, and body weight (e.g. Compton & Vogler, 1975; Miller & Muiioz, 1976; Rutgers Center of Alcohol Studies, 1972). Huber et al. (1976) compared the effectiveness of three BAC training procedures: (a) internal cue training only, (b) external cue training only, and (c) training in both internal and external cue procedures. Their moderate drinking subjects in all groups learned to discriminate BAC to within f 10 mg%, with no significant differences among training procedures. Comparing alternative treatment methods for problem drinkers, Vogler and his colleagues (1977a,b) found no significant difference in effectiveness between an extensive multimodal program that included internal cue training and a basic alcohol education program that incorporated external cue training. In five separate outcome studies employing external cue training within a multimodal approach, Miller and his colleagues (Miller, 1977, 1978; Miller et al., 1976, 1977; Miller & Taylor, 1978a, 1978b) have found follow-up improvement rates in excess of 70%. These studies suggest that external cue training, which does not require use of expensive equipment or in-session drinking, may be the more cost-effective procedure. * Requests for reprints should be sent to William R. Miller, Department of Psychology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A. Documentation is also available for both programs described in this report. 55
56
DANIEL B. MATTHEWSand WILLIAMR. MILLER
The two computer programs described below were developed as aids in the external cue training of BAC discrimination in problem drinkers. BACTAB is a program that provides each client with an individualized BAC estimation table, taking into account both body weight and differences between males and females with regard to the volume distribution of ethanol. ALCOMP was designed to convert clients’ drink-by-drink selfmonitoring cards into weekly summary data usable in outcome research, and to give clients an hour-by-hour estimation of their BAC level throughout the recorded week, arduous and time-consuming tasks by hand calculation. Both programs are written in FORTRAN and are available in interactive or batch processing versions compatible with the IBM 360 computer. BACTAB
Although published tables of BAC are available, they tend to provide data only for a standard weight individual or for a few gross weight categories (e.g. Miller & Muiioz, 1976). Most tables also fail to take into account sex differences in volume distribution of alcohol (Jones & Jones, 1976; Ray, 1972) or to standardize what counts as a “drink.” Finally, tables designed for a range of individuals of necessity reflect a relatively small number of drinks and hours of drinking. One excellent slide rule device overcomes some of these problems, but our clients have found this instrument complicated or inconvenient to use (Rutgers Center, 1972). BACTAB is designed to provide clients or students with BAC tables individualized by both weight and sex. It is based on a standard “drink” unit and provides BAC estimates over a wide range of alcohol consumption and time values.
The input data for BACTAB consist simply of the individual’s code number, weight and sex. A batch processing version of the program permits preparation of multiple tables in a single run, as for a class. The output from BACTAB is a table that gives BAC estimates for up to 25 drinks and for periods of drinking up to 10 hr. A “drink” is defined as the amount of any beverage containing 0.50 oz. (15 ml) of ethanol (Miller, 1977, 1978). The computation of BAC per ounce of ethanol ingested is a simple constant divided by the person’s weight in pounds. Different sources have used various constants. The data reported by Ray (1972) are used in BACTAB, the constants being 7.5 for males and 9.0 for females. Users could easily substitute a different constant, such as the 7.2 figure derived from the Alto-Calculator slide rule (Rutgers Center, 1972). To estimate BAC at a given point in time it is further necessary to account for the amount of alcohol metabolized since consumption. Metabolism rates show substantial individual differences (Kalant, 1971; Lelbach, 1974) and an average figure of 16 mg% per hr has been used in BACTAB. If the individual’s personal metabolism rate has been determined this figure could be substituted. A sample output for a 120lb female is shown in Table 1. Applications of BACTAB
Few problem drinkers have more than a cursory understanding of BAC and its relationship to intoxication, behavioral and physiological manifestations, and legal sanctions. Societal lore suggests many mythical methods for decreasing alcohol’s effects or for accelerating alcohol metabolism. Few drinkers understand that tolerance to alcohol is more behavioral than metabolic. Those who believe themselves to have high metabolic tolerance may disregard warnings relating alcohol consumption to physical dangers or driving safety, assuming personal immunity to these contingencies. Clear education about what does and does not affect BAC is thus an important first step in alcohol education. BACTAB may be used early in treatment to assist clients in setting concrete goals or limits for their drinking. The table should be accompanied by an explanation of
Estimating Table
No. of
Drinks (sets)
1. Blood
1 2 3 4 5 6 7 8 9 10 I1 I2 I3 14 IS 16 I7 18 I9 20 21 22 23 24 25
alcohol
concentration
0
1
2
031 074 111 148 185 222 259 296 333 370 407 444 481 518 555 592 629 666 703 740 777 814 851 888 925
021 058 095 132 169 206 243 280 317 354 391 428 465 502 539 576 613 650 687 724 761 798 835 872 909
005 042 079 II6 I53 190 227 264 301 338 375 412 449 486 523 560 597 634 671 708 745 782 819 856 893
blood
as a function Client 3
of drinks
no. 2468 Female: 4 5
ooo
ooo
026 063 100 137 174 211 248 285 322 359 396 433 470 507 544 581 618 655 692 729 766 803 840 877
010 047 084 I21 I58 195 232 269 306 343 380 417 454 491 528 565 602 639 616 713 750 787 824 861
51
alcohol consumed 120lbs 6
and time taken
7
ooo ooo
ooo
ooo
031 068 I05 142 179 216 253 290 327 364 401 438 415 512 549 586 623 660 697 734 771 808 845
015 052 089 126 163 200 237 274 311 348 385 422 459 496 533 570 607 644 681 718 755 792 829
036 073 110 147 I84 221 258 295 332 369 406 443 480 517 554 591 628 665 702 739 776 813
ooo
ooo ooo
8
to consume
9
ooo ooo
ooo ooo
020 057 094 131 168 205 242 279 316 353 390 427 464 501 538 575 612 649 686 723 760 797
004 041 018 II5 I52 I89 226 263 300 337 374 411 448 485 522 559 596 633 670 701 744 781
ooo
ooo
IO
ooo ooo ooo ooo 025 062 099 136 173 210 247 284 321 358 395 432 469 506 543 580 617 654 691 728 765
the “one drink” unit and a table or discussion of the behavioral and physical effects to be expected at various BAC levels. Within this context a client can select a BAC level as an upper limit that he or she chooses not to exceed. Miller & Muiioz (1976) have recommended two types of limits: a regular limit that represents a ceiling for the average drinking day (most applicable with steady drinkers) and an absolute limit that provides a boundary for any drinking occasion. (We recommend that clients select these limits with regard to the effects of BAC, not by deciding desired consumption level and then finding the corresponding BAC value.) Having set these limits, the client can then use a BACTAB table to determine the number and spacing of drinks required to remain within them. For both students and clients BACTAB provides individualized education regarding the relationship between alcohol consumption and blood alcohol. Students may calculate the approximate number of drinks required to reach important levels such as (a) impairment of judgment, (b) legal intoxication, (c) unconsciousness, and (d) lethal dose. An interviewer who obtains a detailed account of current drinking pattern can also use BACTAB to obtain an estimate of the peak BAC reached by the interviewee during an average drinking week, a statistic useful both in assessment and in outcome research. ALCOMP
ALCOMP was written to perform more complicated computations useful in controlled drinking therapies and research. The input data for ALCOMP are derived from daily self-monitoring cards such as those used in many treatment programs (e.g. Miller & Muiioz, 1976; Sobell & Sobell, 1973). The output provides daily and weekly summary statistics and a table of BAC estimates for the data week. Program
The input to ALCOMP consists of client identification (code number, sex, weight, BAC limit chosen) and dates to which the data correspond, followed by an entry for each drink consumed during all days specified. A single day’s data include the time, amount, and alcohol concentration for each drink, followed by an entry signalling the
58
DANIEL B. MATTHEWS and WILLIAM R. MILLER
end of the data day. Entries are coded for convenience; e.g. 1.5 oz of 80 proof (40%) vodka consumed at 11:30 a.m. is coded as: 11, 30, 1.5, 40. The program echoes each entry in prose to verify accuracy of coding, and translates the drink into Standard Ethanol Content units (SECs) (Miller, 1978); e.g. 11:30 a.m.-l.5 oz, 40.0% 1.2 sets. Output is in three parts. The first section provides weekly and daily summary data. Table 2 is a sample week’s output for a 150 lb male client whose selected BAC limit was 50 mg”/;;. The second part of the output, also shown in Table 2, provides daily statistics for maximum BAC, time of BAC peak, SECs consumed, and time intervals during which the BAC limit and a standard level of 80mg% were exceeded. A third (optional) section of output is a table of estimated BAC at every half hour of every day for the data week. Sample output data for the same client are shown in Table 3. Hours prior to 4:30 p.m. (16.5) have been omitted because biood alcohol was estimated to be zero during these hours. The estimation procedures are identical to those for BACTAB, except that alcohol is assumed to enter the system 12 min after the drink is begun, allowing a standard interval for consumption and absorption. Applications
of ALCOMP
As a therapeutic tool, ALCOMP provides detailed feedback regarding client progress. From summary data the individual can obtain various indices of drinking in excess of goals. Small but significant changes in drinking can be detected and lend themselves to weekly graphing. Of special interest to clients are the total sets (consumption), maximum BAC, and total time over selected BAC goal, all good indicators of progress. The BAC estimate table allows a client to examine.factors such as the impact of various kinds of drinks, the compounding effects of drinks as a function of spacing, and the length of time required to metabolize alcohol. Hand calculation of such data is arduous if not impossible. Potential applications of ALCOMP in treatment outcome research are straightforward. The summary statistics provide a range of useful dependent variables on an ongoing basis. In addition to the absolute outcome data provided by pre/post measures, these weekly and daily data permit examination of the rate of progress and the relative
Table
2. Summary
Times over 80
Mon 27 0.044
for client
1357
6 2
Drinking days (DD) Days over 050 mg”,, Days over 080 mg”,, Days five or more sets Total sets Sets, DD Time over 050-week Time over 80-week Max bat for week Time and day of max Max bac/DD Day,‘Date High bat Time of High bat Sets consumed Times over goal
data
0
21.6 3.6 3.7 0.6 0.087 Fri 18.2 0.053 Tue 28 0.046
Wed 29 0.000
Thu 30 0.055
Fri 31 0.087
Sat 1 0.047
Sun 2 0.038
19.7
18.7
0.0
20.3
18.2
18.7
18.7
3.6
3.7
0.0
3.6
4.8
3.9
1.9
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
19.2 19.2 20.3 20.5
16.7 17.0 17.3 20.5
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
17.6 17.8 18.2 18.6
0.0 0.0 0.0 0.0
0.0 0.0 0.0 0.0
Estimating Table
16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0 20.5 21.0 21.5 22.0 22.5 23.0 23.5 24.0
3. BAC estimates
blood
59
alcohol
as a function
of time for client
1357
Mon 27
Tue 28
Wed 29
Thu 30
Fri 31
Sat I
Sun 2
000 000 000 000 018 034 026 039 031 023 037 029 021 013 005 000
000 000 018 034 026 042 034 026 018 010 002 015 007 000 000 000
000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000
000 000 000 000 042 034 046 038 051 043 035 027 019 011 003 000
037 050 064 077 083 075 067 059 051 043 035 027 019 011 003 000
000 000 018 034 026 043 035 027 019 011 003 000 023 015 007 000
000 000 Oc@ 000 018 034 026 018 010 002 000 000 000 000 000 000
impact of program components on drinking dimensions through repeated measures analysis of variance and time series analysis.
techniques
such
as
DISCUSSION
Both BACTAB and ALCOMP have been employed in two treatment outcome studies involving more than 100 clients (Miller & Taylor, 1978a, 1978b). Therapists and research assistants have used the programs readily after brief instruction, and clients have responded favorably to this individualized form of feedback. These programs may also have preventive applications. BACTAB tables have been used as instructional aids in classes at the University of New Mexico, and the program has been made anonymously available to all users of our computing system. Although BAC computations are based upon the best available data, it is likely that changes in the basic formulae will be warranted as future data become available. Compton & Vogler (1975) have reported considerable variability in accuracy of BAC estimates from the Alto-Calculator. This variability may be reduced by including as predictor variables other factors influencing BAC; e.g. age, race, drinking history, liver function data, recent food consumption, emotional state. Data are needed regarding the relationship between such variables and BAC as measured by actual blood or breath samples. Such data may provide a basis for modifying the constants or calculation procedures now employed in BACTAB and ALCOMP. REFERENCES Bois, C. & Vogel-Sprott, M. Discrimination of low blood alcohol levels and self-titration skills in social drinkers. Quarterly Journal of Studieson Alcohol, 1974, 35, 8697. Caddy, G. R. & Lovibond, S. H. Self-regulation and discriminated aversive conditioning in the modification of alcoholics’ drinking behavior. Behacior Therap!, 1976, 7, 223-230. Compton, J. V. & Vogler. R. E. Validation of the Alto-calculator. Psychological Reports. 1975, 36, 977-978. Huber, H., Karlin, R. SC Nathan, P. E. Blood alcohol level discrimmation by nonalcoholics: The rote of internal and external cues. Journal of Studieson AIcohol, 1976, 37, 27-39. Kalant. H. Absorption diffusion, distribution, and elimination of ethanol: Effects on biological membranes. In B. Kissin & H. Begleiter (Eds), The Biology of Alcoholism Vol. I. New York: Plenum Press, 1971. Lelbach, W. K. Organic pathology related to volume and pattern of alcohol use. In R. J. Gibbins, Y. Israel, H. Kalant, R. E. Popham, W. S. Schmidt & R. G. Smart (Eds), Research Advances in Alcohol and Drug Problems Vol. I. New York: Wiley, 1974. Lovibond, S. H. & Caddy, G. Discriminated aversive control in the moderation of alcoholics’ drinking behavior. Behacior Therapy, 1970, 1, 437444. Miller, W. R. Behavioral self-control training in the treatment of problem drinkers. In R. B. Stuart (Ed.). Behacioral Self-Management: Strategies, Techniques and Outcomes. New York : Brunner/Mazel, 1977. Miller, W. R. Behavioral treatment of problem drinkers: A comparative outcome study of three controlled drinking therapies. Journal of Consulting and Clinical Psychology, 1978, 46, 74-86. . Miller, W. R. & Mmioz. R. F. How to Control Your Drinking. Englewood Cliffs. N.J.: Prentice-Hall, 1976. Miller, W. R. & Taylor, C. A. Relatice eflecticeness of bibliotherapy, indiaidual and group self-control training in the treatment of problem drinkers. Unpublished manuscript, University of New Mexico, 1978a.
DANIEL B. MATTHEWS and WILLIAM R. MILLER
60
Miller. W. R. & Taylor, C. A. Eoaluution CI/ u module program for problem drinkers. HEW/NlAAA grant No. I-R03-AA03450-01, University of New Mexico. 3978b. Miller. W. R.. Gribskov. C. & Mort& R. .Efli!ctirc)ne.ss of’ (1 se/$conrro/ munuul for problem drinkers with trnd wit!tout therapist c’onttrc’t. Unpublished manuscript. University of Oregon. 1976. Miller W. R.. Pechacek. T. F. & Hamburg. S. Group behavior thrrup~~ for probkem drinkers. Unpublished manuscript. Palo Alto Veterans Administration Hospital. 1977. Ray. 0. S. Drru/s. Sociczr!: um/ ffuruun Behurior. St. Louis: C. V. Mosby. 1972. Rutgers University Center of Alcohol Studies. A/co-Calculator: An Educational Instrument. New Brunswick. N.J.: Author. 1972. Silverstein. S. J., Nathan. P. E. & Taylor, H. A. Blood alcohol level estimation and controlled drinking by chronic alcoholics. Behurior Therapy. 1974, 5, l-15. Sobell. L. C. & Sobell. M. B. A self-feedback technique to monitor drinking behavior in alcoholics. Behaciour Rrseorch
Vogler,
_ Journul
Vogler.
and Therrrpy,
R. E.. Compton. of Conskting
R. E.. Weissbach.
and Thrrtrp~.
1973. II,
237-238.
J. V. & Weissbach. and Clinical
T. A. Integrated
Ps.vcho/oyy.
T. A. & Compton.
behavior
change
techniques
for alcohol
abuse.
for alcoholism.
1975, 43, 233-243.
J. V. Learning
techniques
Behucior
Resetrrch
1977a. 15. 3 I-38.
Vogler. R. E.. Weissbach. T. A., Compton, for problem drinkers in the community.
J. V. & Martin. Journal
G. T. Integrated
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