PRIVACY ACT MATERIAL REMOVED 2 Table V. Cell Volume (Vrbc) at Normal Hody Temperature and as Found by In- jecting a Second Dose of Tagged Cells ajter Rectal Temperature Had Fallen to 27-28°C. Two Patients Subjected to Hypothermia for Suryical Operation. _. Subject Tone. Mixing 1 Vibe ' ct 55 65 1.60 1.61 41.2 41.0 27.4 26.9 26.7 16 32 52 1.4 1.42 1.4 46.6 4646 46.9 First dose of cells 377 37.7 $1 59 2.95 2.95 47.1 4.4 Second dosa 27.0 26.7 26.2 15 25 62 2.68 2.61 2.73 50.6 50.6 48.2 e c . nin. First dose of celle 3&0 37.8 Second dose a> i s %q cells iously low values (Nylin & Hedlund 1947; Krown, Hopper, Sampson & Mudrick 1951; Reilly, French, Lau, Scott & White 1954; Prichard et af. 1955). In cases of congestive heart failure we take samples at intervals of 15 nsinutes fur one hour or longer. The re- sultant “mixing curves” are nearly always flat by the end of half an hour. Caution is required in interpreting results from tests made during shock or hypothermia because there 4s evidence that portions of the lee r tree may never be reached by the tagged cel in these conditions (Rodbard, Saiki, Mahw & Young 1951; Prentke, Otney, !Artz & Howard 1954). Thus, the mixing curve may be flat, bud the pliseavéd volume of distribu- tion repregegts bile fi culating, rather than the total, ce ‘Observations on two patients fer to hypothermia before seri ¥ * % % Meer F oa rocedures (Table V) illustrate this wh Sob POR DETERMINATION OF MED CELL VOLUME &. WENNESLAND ET AL. point. Vrbe was measured in the us ual wa, hypothe, ple Vi Repeated measurements of coll and whole bloud volume in 17 healthy before induction of anesthesia and mia. A second dose of tagged cells Was na after rectal temperature had fallen aos mien at 3 do ST week intervals. Ta a tonereat 10° C. Vrbc appeared to be 7—10 per ¢ ard eh a yeasure- subpct lower during hypothermia than just oie to its induction. Similar results were obainey in 3-of 4 splenectomized dogs studied du ting experimental hypothermia. mints an s 4 23 Reproducibility and relative magnitude of component sources of error. In three experiments, subjects were given ; a second dose of tagged cells immediate), ; fl after the first. Differences between first and second Vrbc were 0, 90 and 50 ml, or 0,45 and 3.4 per cent. Seventeen healthy men were subjected to second or third tests after intervals « 3 it 24 u Jarger amounts of radioactivity needed for immediately sequential measuteinents (Ta: 2 ble VI). The mean of 20 differences’ was 7? ml of cells, or 3.9 per cent (range, 10— 10 190 ml; 0.6—8.§ per: cent), These result, define the outer Ilmits of experimental ersur possible changes within subjects. Difference, f\the same magnitude, however, have beeu Mc o 472 a7 ava 4u3 aul aux avo 421 “O4 any 495 ane 4K 4K 4814 452 456 455 454 2 WO 47 ue ° a" 452 407 - - Change Fuund |Differencel Change Found [Difference I %o | i 2.44 225 019 78 514 479 0.39 25 1ial Ro 005 2? On Oa 26 ws 167 be2 1.66 es 430 419 490 vos 0.04 001 3.0 24 06 0 6 440 ‘oc 489 010 005 toe 24 13 e 367 366 a7 3.67 400 420 $09 533 469 453 456 5 07 4.00 io vo 03 out 1 020 om 50 47 051 on 1.2 402 ate 455 44% 404 47 o. 4s ow 10 1 197 180 1st 131 176 193 202 2.30 243 23 2.04 183 1493 0.16 0.01 58 O13 28 42 ; 5. 0.09 4.2 005 {°°0.09 0.50 35 v.01 06 0u8 45 ou st 1x2 188 000 33 uw ‘1 var 0 68 163 te 178 ae 214 20) 219 442 22 224 iw 400 ne 142 is 0.07 3 44 415 raz 205 Ot} 43 Whole Hiood Ceils 447 ; ae s Ns , ufind by others who repeated measurements + at’shorter intervals. Those measuring VCr* feported differences of 0.4—10.0 per ceut (Keilly ct af. 1954), 4 per cent (Kisenberg 1954) and 2—8 per cent (Walser, Duffy & “O ae “ ee Hemiato- 443 ae 49 455 3 or beyond, since they ate affected not ouh by afl the components of the method but by (Chaplin 1954), 3.5—7.5 per cent of cells » 4 3 ts . S—SI weeks in order to avoid using the Griffith 1956). The experience with P3® his been similar. Differences between paired measurements were 0.1—G.2 per cent of cells . a_ 227 0 U8 us 9 3.9 ie O16 7 01) 32 469 047 100 516 512 od 4s 394 te 025 64 434 a7 ov 8S any 34% 23 ® Uncorrected for trapped plisiia aed read to the dop of the ce colunm 0.23 0.18 §2 41

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