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Effect of acetazolamide on physiological changes in fifteen-year olds at high altitude
Author
Thompson, Sarah
Supervisor
Balasekaran, Govindasamy
Abstract
Physiological research at high altitude has focused predominantly on adult males. The purpose of this investigation was to determine the physiological effect of high altitude (HA) on 15-year olds. The subjects spent 3 days at 3,500m before commencing a 10-day trek (3,500-5 loom).
The effect of the carbonic anhydrase inhibitor, acetazolamide (act.), was investigated comparing a control group (control; n= 12) and a treatment group (act; n=13). The treatment group took 250mg of acetazolamide daily from day 1-7 inclusive during the high altitude sojourn. Resting Heart Rate (RHR) and Acute Mountain Sickness (AMS) were measured each morning and afternoon; Resting Blood Pressure (RBP) was measured each afternoon. AMS scores were recorded using the Lake Louise questionnaire throughout the stay at altitude.
Pre and post blood samples were taken at sea level (SL) one week before departure and within 40 hours on return to SL and analysed for changes in haemoglobin (Hb) and hematocrit (Hct). Plasma volume (PV) changes were estimated using Dill and Costill's method.
An independent t test was applied to test for significant differences between the treatment and control group on RHR and RBP. A paired dependent t test was applied to test for significant differences for each group on RHR and RBP at SL and at HA. Differences between the groups AMS scores were analysed using the Mann-Whitney U test.
RHR was always significantly different from SL (p<10.05) except for the morning of day 4 (act) and the morning of day 10 (control). RHR was significantly higher in the control group on days 2,3 and 5 during drug administration. RHR and high altitude (HA) were positively correlated (control r=0.83 and act ~0.69, p<0.05).
Systolic Blood Pressure (SBP) was always significantly greater at HA for both groups (p<0.05 or less) with the exception of day 10 (control and act) and day 11 (control). On day 4, SBP (control) was significantly greater than SBP (act) group; this was reversed on day 13 (p<0.03). Diastolic Blood Pressure (DBP) was significantly greater than at SL on days 6,7,9,1 I, 12,and 13 (control) and days 3 to 9 and l l to 13 (act) (~<0.05). The groups did not differ significantly from each other on any occasion. DBP and HA was positively correlated (control ~0.71 and act ~0.70; p<0.05).
The pre and post blood analysis is as follows: Pre Hb (control) mean 14.4 g/dl ± 1.3, post Hb (control) 15.4 g/dl ± 1.6. Pre Hb (act) 14.7 g/dl ± 0.8, post Hb (act) 15.6 g/dl ± 1.2. Pre Hct. (control) mean 40.3 %± 2.7, post Hct (control) 47.2% ± 3.9. Pre Hct (act) 42.0% ± 2.2, post Hct (act) 46.9% ± 3.0.
Hb and Hct groups were significantly different to sea level values (p<0.05). There was no significant difference between the groups' pre and post altitude for Hb and Hct. PV decreased by 18.4% ± 11.3 (control) and 14.0% ± 10.0 (act), again no significant differences were found between groups.
The groups did not differ significantly from each other except on day 12 (am) when the AMS scores of the acetazolamide group were significantly greater than the control group (p<0.05). A trend of low scores was seen for several days in both groups after the first HA pass (4,900111) had been crossed.
Findings indicate that RHR and RBP increase at high altitude. Increases in RHR may be less pronounced in those taking acetazolamide, however, further study over a longer treatment period at HA is recommended. Blood changes after 17 days at HA resulted in similar increases in Hb and Hct and similar decreases in PV for both groups. Taking blood samples during the HA stay would help to show the changes in Hb, Hct and PV.
This study found teenagers experienced similar degrees of AMS with or without acetazolamide. Teenagers may be poor at judging AMS and have a tendency to over estimate their symptoms due to fatigue, heat and dehydration.
The effect of the carbonic anhydrase inhibitor, acetazolamide (act.), was investigated comparing a control group (control; n= 12) and a treatment group (act; n=13). The treatment group took 250mg of acetazolamide daily from day 1-7 inclusive during the high altitude sojourn. Resting Heart Rate (RHR) and Acute Mountain Sickness (AMS) were measured each morning and afternoon; Resting Blood Pressure (RBP) was measured each afternoon. AMS scores were recorded using the Lake Louise questionnaire throughout the stay at altitude.
Pre and post blood samples were taken at sea level (SL) one week before departure and within 40 hours on return to SL and analysed for changes in haemoglobin (Hb) and hematocrit (Hct). Plasma volume (PV) changes were estimated using Dill and Costill's method.
An independent t test was applied to test for significant differences between the treatment and control group on RHR and RBP. A paired dependent t test was applied to test for significant differences for each group on RHR and RBP at SL and at HA. Differences between the groups AMS scores were analysed using the Mann-Whitney U test.
RHR was always significantly different from SL (p<10.05) except for the morning of day 4 (act) and the morning of day 10 (control). RHR was significantly higher in the control group on days 2,3 and 5 during drug administration. RHR and high altitude (HA) were positively correlated (control r=0.83 and act ~0.69, p<0.05).
Systolic Blood Pressure (SBP) was always significantly greater at HA for both groups (p<0.05 or less) with the exception of day 10 (control and act) and day 11 (control). On day 4, SBP (control) was significantly greater than SBP (act) group; this was reversed on day 13 (p<0.03). Diastolic Blood Pressure (DBP) was significantly greater than at SL on days 6,7,9,1 I, 12,and 13 (control) and days 3 to 9 and l l to 13 (act) (~<0.05). The groups did not differ significantly from each other on any occasion. DBP and HA was positively correlated (control ~0.71 and act ~0.70; p<0.05).
The pre and post blood analysis is as follows: Pre Hb (control) mean 14.4 g/dl ± 1.3, post Hb (control) 15.4 g/dl ± 1.6. Pre Hb (act) 14.7 g/dl ± 0.8, post Hb (act) 15.6 g/dl ± 1.2. Pre Hct. (control) mean 40.3 %± 2.7, post Hct (control) 47.2% ± 3.9. Pre Hct (act) 42.0% ± 2.2, post Hct (act) 46.9% ± 3.0.
Hb and Hct groups were significantly different to sea level values (p<0.05). There was no significant difference between the groups' pre and post altitude for Hb and Hct. PV decreased by 18.4% ± 11.3 (control) and 14.0% ± 10.0 (act), again no significant differences were found between groups.
The groups did not differ significantly from each other except on day 12 (am) when the AMS scores of the acetazolamide group were significantly greater than the control group (p<0.05). A trend of low scores was seen for several days in both groups after the first HA pass (4,900111) had been crossed.
Findings indicate that RHR and RBP increase at high altitude. Increases in RHR may be less pronounced in those taking acetazolamide, however, further study over a longer treatment period at HA is recommended. Blood changes after 17 days at HA resulted in similar increases in Hb and Hct and similar decreases in PV for both groups. Taking blood samples during the HA stay would help to show the changes in Hb, Hct and PV.
This study found teenagers experienced similar degrees of AMS with or without acetazolamide. Teenagers may be poor at judging AMS and have a tendency to over estimate their symptoms due to fatigue, heat and dehydration.
Date Issued
2003
Call Number
QP82.2.A4 Tho
Date Submitted
2003