772 Proc. roy. Soc. Med. Volume 68 December 1975 Table 3 FVC on first postoperative day as a percentage of preoperative FVC. Means of three readings, each patient receives one dose of each drug, patients supine
Etidocaine Case No. 1 2 3 4 5 6 7 Mean
Bupivacaine
0.5S% 0.375Y% 0.5% 0.375% 80 44 51 36 61 26 54 50
79 61 45 -* 49 -* -* 58
87 49 49 44 49 31 41 50
79 47 47 37 58 25 47 48
* Inadequate analgesia
Table 4 FVC on first postoperative day as a percentage of preoperative FVC. Means of three readings, each patient receives one dose of each drug, patients supine Injections
Case No. 1 2 3 4 5 6 7 Mean
First Second 80 79 44 49 51 45 36 37 49 58 31 26 41 47 47 48
Third 79 47 49 44 61 25 54 51
Fourth 87 61 47
-0 49 --
-0 53
* Inadequate analgesia
bupivacaine for 100-160 minutes and 0.375% bupivacaine for 85-130 minutes. The measurements of motor block made preoperatively, without intervening surgery, showed only small and variable falls in the values (Table 2), of a similar order to those found by other workers using 1.5 % lignocaine in a similar technique (Moir 1963, Wahba et al. 1972). Postoperatively the percentage reduction in FVC was not consistently less or greater with any one solution (Table 3), implying that neither drug produces a greater degree of block. A further finding was that there was no progressive fall in FVC with successive injections, implying no increasing degree of motor block (Table 4). REFERENCES Adams H J, Kronberg G H & Takman B H (1972) Journal ofPharmaceutical Sciences 61, 1829 Ellis R M, Hillman G & Simpson B R (1968) Excerpta Medica International Congress Series 200, 1241 Lund P C (1975) British Journal of Anaesthesia 47, 314 Lund P C, Cwik J C & Pagdanganan R T (1973) Anesthesia and Analgesia 52, 482 Moir D D (1963) British Journal oJfAnacsthesia 35, 3 Scott D B, Jebson P B R & Boyes R N (1973) British Journal of Anacsthesia 45, 1010 Simpson B R, Parkhouse J, Marshall R & Lambrechts W (1961) British Journal ofAnacsthesia 33, 628 Wahba W M, Craig D B, Don H F & Becklake M R (1972) Canadian Anacsthetic Society Journal 19, 8
22 Dr J A S Gamble (Department ofAnwsthetics, Queen's University ofBelfast, Grosvenor Road, Belfast BTJ2 6BJ) Some Factors Influencing the Absorption of Diazepam
Plasma diazepam levels measured by gas-liquid chromatography following single dose administration have been found to be influenced both by the route of administration and the administrator (Gamble J A S, Dundee J W & Assaf R A E, 1975, Ana?sthesia 30, 164-169). This has led to an investigation of the factors influencing the absorption of diazepam. To assess the importance of muscle blood flow in absorption, plasma diazepam was measured following intramuscular administration in twenty student volunteers half of whom rested and half of whom exercised. In the exercised group plasma levels were significantly higher and increased more rapidly than in the rested group. Following oral administration of diazepam the concurrent administration of metoclopramide, aluminium hydroxide, morphine, pethidine and atropine has been shown to influence plasma diazepam levels. The addition of metoclopramide or aluminium hydroxide has been shown to increase the rate of absorption, the former giving significantly higher peak levels. Morphine, pethidine and atropine decreased the rate of absorption, giving significantly lower plasma diazepam levels over the 90 minute period studied. The factors which have been shown to influence the absorption of diazepam may be summarized thus: (1) Route of administration. (2) Administrator. (3) Muscle activity. (4) Concurrently administered drugs: (a) metoclopramide; (b) aluminium hydroxide; (c) morphine; (d) pethidine; (e) atropine.
Dr P J O'Shea, Dr T M Savage and Dr B Walton (The London Hospital, Whitechapel, London El JBB)
Effect of Oxygen Insufflation During One-lung Annsthesia
During thoracic anesthesia with one-lung ventilation, it is well established that the arterial oxygen tension (Pao2) falls significantly due to the shunting of blood through the collapsed lung (Kerr et al. 1974, Torda et al. 1974).
Etidocaine Case No. 1 2 3 4 5 6 7 Mean
Bupivacaine
0.5S% 0.375Y% 0.5% 0.375% 80 44 51 36 61 26 54 50
79 61 45 -* 49 -* -* 58
87 49 49 44 49 31 41 50
79 47 47 37 58 25 47 48
* Inadequate analgesia
Table 4 FVC on first postoperative day as a percentage of preoperative FVC. Means of three readings, each patient receives one dose of each drug, patients supine Injections
Case No. 1 2 3 4 5 6 7 Mean
First Second 80 79 44 49 51 45 36 37 49 58 31 26 41 47 47 48
Third 79 47 49 44 61 25 54 51
Fourth 87 61 47
-0 49 --
-0 53
* Inadequate analgesia
bupivacaine for 100-160 minutes and 0.375% bupivacaine for 85-130 minutes. The measurements of motor block made preoperatively, without intervening surgery, showed only small and variable falls in the values (Table 2), of a similar order to those found by other workers using 1.5 % lignocaine in a similar technique (Moir 1963, Wahba et al. 1972). Postoperatively the percentage reduction in FVC was not consistently less or greater with any one solution (Table 3), implying that neither drug produces a greater degree of block. A further finding was that there was no progressive fall in FVC with successive injections, implying no increasing degree of motor block (Table 4). REFERENCES Adams H J, Kronberg G H & Takman B H (1972) Journal ofPharmaceutical Sciences 61, 1829 Ellis R M, Hillman G & Simpson B R (1968) Excerpta Medica International Congress Series 200, 1241 Lund P C (1975) British Journal of Anaesthesia 47, 314 Lund P C, Cwik J C & Pagdanganan R T (1973) Anesthesia and Analgesia 52, 482 Moir D D (1963) British Journal oJfAnacsthesia 35, 3 Scott D B, Jebson P B R & Boyes R N (1973) British Journal of Anacsthesia 45, 1010 Simpson B R, Parkhouse J, Marshall R & Lambrechts W (1961) British Journal ofAnacsthesia 33, 628 Wahba W M, Craig D B, Don H F & Becklake M R (1972) Canadian Anacsthetic Society Journal 19, 8
22 Dr J A S Gamble (Department ofAnwsthetics, Queen's University ofBelfast, Grosvenor Road, Belfast BTJ2 6BJ) Some Factors Influencing the Absorption of Diazepam
Plasma diazepam levels measured by gas-liquid chromatography following single dose administration have been found to be influenced both by the route of administration and the administrator (Gamble J A S, Dundee J W & Assaf R A E, 1975, Ana?sthesia 30, 164-169). This has led to an investigation of the factors influencing the absorption of diazepam. To assess the importance of muscle blood flow in absorption, plasma diazepam was measured following intramuscular administration in twenty student volunteers half of whom rested and half of whom exercised. In the exercised group plasma levels were significantly higher and increased more rapidly than in the rested group. Following oral administration of diazepam the concurrent administration of metoclopramide, aluminium hydroxide, morphine, pethidine and atropine has been shown to influence plasma diazepam levels. The addition of metoclopramide or aluminium hydroxide has been shown to increase the rate of absorption, the former giving significantly higher peak levels. Morphine, pethidine and atropine decreased the rate of absorption, giving significantly lower plasma diazepam levels over the 90 minute period studied. The factors which have been shown to influence the absorption of diazepam may be summarized thus: (1) Route of administration. (2) Administrator. (3) Muscle activity. (4) Concurrently administered drugs: (a) metoclopramide; (b) aluminium hydroxide; (c) morphine; (d) pethidine; (e) atropine.
Dr P J O'Shea, Dr T M Savage and Dr B Walton (The London Hospital, Whitechapel, London El JBB)
Effect of Oxygen Insufflation During One-lung Annsthesia
During thoracic anesthesia with one-lung ventilation, it is well established that the arterial oxygen tension (Pao2) falls significantly due to the shunting of blood through the collapsed lung (Kerr et al. 1974, Torda et al. 1974).
