The Effect of External PEEP on Work of Breathing in Patients with Auto-PEEP / 결핵

BACKGROUND: Auto-PEEP which develops when expiratory lung emptying is not finished until the beginning of next inspiration is frequently found in patients on mechanical ventilation. Its presence imposes increased risk of barotrauma and hypotension, as well as increased work of breathing (WOB) by adding inspiratory threshold load and/or adversely affecting to inspiratory trigger sensitivity. The aim of this study is to evaluate the relationship of auto-PEEP with WOB and to evaluate the effect of PEEP applied by ventilator (external PEEP) on WOB in patients with auto-PEEP. METHOD: 15 patients, who required mechanical ventilation for management of acute respiratory failure, were studied. First, the differences in WOB and other indices of respiratory mechanics were examined between 7 patients with auto-PEEP and 8 patients without auto-PEEP. Then, we applied the 3 cm H2O of external PEEP to patients with auto-PEEP and evaluated its effects on lung mechanics as well as WOB. Indices of respiratory mechanics including tidal volume (V(T)), repiratory rate, minute ventilation (V(E)), peak inspiratory flow rate (PIFR), peak expiratory flow rate (PEFR), peak inspiratory pressure (PIP), T(I)/T(TOT), auto-PEEP, dynamic compliance of lung (Cdyn), expiratory airway resistance (RAWe), mean airway resistance (RAWm), P(0.1), work of breathing performed by patient (WOB), and pressure-time product (PTP) were obtained by CP-100 Pulmonary Monitor (Bicore,USA). The values were expressed as meanSEM (standard error of mean). RESULTS: 1) Comparison of WOB and other indices of respiratory mechanics in patients with and without auto-PEEP: There was significant increase in WOB (1.71 +/-0.24 vs 0.500.19 J/L, p=0.007), PTP (317+/-70 vs 98+/-36 cm H2O * sec/min, p=0.023), RAWe (35.6+/-5.7 vs 18.2+/-2.3 cm H20/L/sec, p=0.023), RAWm (28.8+/-2.5 vs 11.9+/-2.0 cm H2O/L/sec, p=0.001) and P0.1 (6.21.0 vs 2.9+0.6 cm H2O, p=0.021) in patients with auto-PEEP compared to patients without auto-PEEP. The differences of other indices including V(T), PEFR, V(E) and T(I)/T(TOT) showed no significance. 2) Effect of 3 cm H2O external PEEP on respiratory mechanics in patients with auto-PEEP: When 3 cm H2O of external PEEP was applied, there were significant decrease in WOB (1.71+/-0.24 vs 1.20+/-0.21 J/L, p=0.021) and PTP (317+/-70 vs 231+/-55 cm H2O * sec/min, p=0.038). RAWm showed a tendency to decrease (28.8+/-2.5 vs 23.9+/-2.1 cm H2O, p=0.051). But PIP was increased with application of 3 cm H2O of external PEEP (16+/-2 vs 22+/-3 cm H2O, p=0.008). V(T), V(E), PEFR, T(I)/T(TOT) and Cdyn did not change significantly. CONCLUSION: The presence of auto-PEEP in mechanically ventilated patients was accompanied with increased WOB performed by patient, and this WOB was decreased by 3 cm H2O of externally applied PEEP. But, with 3 cm H2O of external PEEP, increased PIP was noted, implying the importance of close monitoring of the airway pressure during application of external PEEP.

The Effect of Pressure Support on Respiratory Mechanics in CPAP and SIMV / 결핵

BACKGROUND: Pressure support(PS) is becomimg a widely accepted method of mechanical ventilation either for total unloading or for partial unloading of respiratory muscle. The aim of the study was to find out if PS exert different effects on respiratory mechanics in synchronized intermittent mandatory ventilation(SIMV) and continuous positive airway pressure (CPAP) modes. METHODS: 5, 10 and 15 cm H2O of PS were sequentially applied in 14 patients(69+/-12 yrs, M:F=9:5) and respiratory rate (RR), tidal volume(VT), work of breathing(WOB), pressure time product(PTP), P(0.1), and T(1)/T(TOT) were measured using the CP-100 pulmonary monitor(Bicore, USA) in SIMV and CPAP modes respectively. RESULTS: 1) Common effects of PS on respiratory mechanics in both CPAP and SIMV modes As the level of PS was increased(0, 5, 10, 15 cm H2O), VT was increased in CPAP mode(0.28+/-0.09, 0.29+/-0.09, 0.31+/-0.11, 0.34+/-0.12 L, respectively, p=0.001), and also in SIMV mode(0.31+/-0.15, 0.32+/-0.09, 0.34+/-0.16, 0.36+/-0.15 L, respectively, p=0.0215). WOB was decreased in CPAP mode(1.40+/-1.02, 1.01+/-0.80, 0.80+/-0.85, 0.68+/-0.76 joule/L, respectively, p=0.0001), and in SIMV mode(0.97+/-0.77, 0.76+/-0.64, 0.57+/-0.55, 0.49+/-0.49 joule/L, respectively, p=0.0001). PTP was also decreased in CPAP mode(300+/-216, 217+/-165, 179+/-187, 122+/-114cm H2O * sec/min, respectively, p=0.0001), and in SIMV mode(218+/-181, 178+/-157, 130+/-147, 108+/-129cm H2O.sec/min, respectively, p=0.0017). 2) Different effects of PS on respiratory mechanics in CPAP and SIMV modes By application of PS (0, 5, 10, 15 cm H2O), RR was not changed in CPAP mode(27.9+/-6.7, 30.0+/-6.6, 26.1+/-9.1, 27.5+/-5.7/min, respectively, p=0.505), but it was decreased in SIMV mode (27.4+/-5.1, 27.8+/-6.5, 27.6+/-6.2, 25.1+/-5.4/min, respectively, p=0.0001). P(0.1) was reduced in CPAP mode(6.2+/-3.5, 4.8+/-2.8, 4.8+/-3.8, 3.9+/-2.5 cm H2O, respectively, p=0.0061), but not in SIMV mode(4.3+/-2.1, 4.0+/-1.8, 3.5+/-1.6, 3.5+/-1.9 cm H2O, respectively, p=0.054). T(1)/T(TOT) was decreased in CPAP mode(0.40+/-0.05, 0.39+/-0.04, 0.37+/-0.04, 0.35+/-0.04, respectively, p=0.0004), but not in SIMV mode(0.40+/-0.08, 0.35+/-0.07, 0.38+/-0.10, 0.37+/-0.10, respectively, p=0.287). 3) Comparison of respiratory mechanics between CPAP+PS and SIMV alone at same tidal volume. The tidal volume in CPAP+PS 10 cm H2O was comparable to that of SIMV alone. Under this condition, the RR(26.1+/-9.1, 27.4+/-5.1/min, respectively, p=0.516), WOB(0.80+/-0.85, 0.97+0.77 joule/L, respectively, p=0.485), P0.1(3.9+/-2.5, 4.3+/-2.1 cm H2O, respectively, p=0.481) were not different between the two methods, but PTP(179+/-187, 218+/-181 cmH2O.sec/min, respectively, p=0.042) and T(1)/T(TOT)(0.37+/-0.04, 0.40+/-0.08, respectively, p=0.026) were significantly lower in CPAP+PS than in SIMV alone. CONCLUSION: PS up to 15 cm H2O increased tidal volume, decreased work of breathing and pressure time product in both SIMV and CPAP modes. PS decreased respiration rate in SIMV mode but not in CPAP mode, while it reduced central respiratory drive(P(0.1)) and shortened duty cycle (T(1)/T(TOT)) in CPAP mode but not in SIMV mode. By 10 cm H2O of PS in CPAP mode, same tidal volume was obtained as in SIMV mode, and both methods were comparable in respect to RR, WOB, P(0.1), but CPAP+PS was superior in respect to the efficiency of the respiratory muscle work (PTP) and duty cycle(T(1)/T(TOT)).

Clinical Aspects of Bacteremia in Medical and Surgical Intensive Care Units / 결핵

BACKGROUND: Intensive care units(ICUs) probably represent the single largest identifiable source of infection within the hospital. Although there are several studies on ICU infections in respect to their bacteriology or mortality rate for individual types of ICU, few studies have compared ICU infections between different types of ICU. The aim of this study was to identify clinical differences in bacteremia between medical ICU(MICU) and surgical ICU(SICU) patients. METHODS: 256 patients with bacteremia were retrospectively evaluated. Medical records were reviewed to obtain the clinical and bacteriologic informations. RESULTS: 1) The mean age of the patients with bacteremia of MICU(58.6+/-17.2 yr) was greater than that of all MICU patients(54.3+/-17.1 yr)(p0.05). ICU stay was longer(MICU patients: 23.4 +/-40.8 day, SICU patients: 30.3 +/-26.8 day) than the mean stay of all patients(6.8+/-15.5 day)(p<0.05, respectively). Bacteremia of both ICU patients developed past the average day of ICU stay(all MICU patients: 7.9 day, all SICU patients: 6.0 day, MICU bacteremia: 19th day, SICU bacteremia: 17th day of ICU stay)(p<0.05, respectively). 2) There were no significant differences in mean age, sex, and length of stay of both ICU patients with bacteremia. 3) Use of antibiotics or steroid, use of percutaneous devices and invasive procedures before development of bacteremia were more frequent in SICU patients than in MICU patients(prior antibiotics use: MICU 45%, SICU 63%, p<0.05; steroid use: MICU 14%, SICU 36%, p<0.01; use of percutaneous devices: MICU 19%, SICU 39%, p<0.01; invasive procedures: MICU 19%, SICU 61%, p<0.01). 4) The prevalence of community acquired infections was significantly higher in MICU patients than in SICU patients(MICU 42%, SICU 9%)(p<0.01), whereas SICU patients showed higher prevalence of ICU-acquired infection than MICU patients(MICU 48%, SICU 78%)(p<0.01). 5) There were no differences in causative organisms, primary sites of infection and time interval to bacteremia between both ICUs. 6) There were no significant differences in outcome according to pathogenic organisms or primary sites of infection. 7) The mortality rate was higher in patients with bacteremia than without bacteremia(MICU mortality rate: patients with bacteremia 72.5%, patients without bacteremia 36.0%, p<0.01; SICU mortality rate: patients with bacteremia 40.3%, patients without bacteremia 8.5%, p<0.05), and the mortality rate of MICU bacteremia was significantly higher compared with that of SICU bacteremia(MICU 72.5%, SICU 40.3%)(p<0.01). CONCLUSION: ICU patients with bacteremia stayed longer before the development of bacteremia, and showed higher mortality than the overall ICU population. The incidence of bacteremia was higher in MICU patients than SICU patients. MICU patients with bacteremia showed higher prevalence of liver diseases and acute respiratory failure, community-acquired bacteremia and greater mortality rate than SICU patients with bacteremia. SICU patients with bacteremia, on the other hand, showed higher prevalence of trauma, prior use of immunosuppressive agents, invasive procedures, and ICU-acquired bacteremia, and lower mortality rate than MICU patients with bacteremia.

The Prognostic Value of the First Day and Daily Updated Scores of the APACHE III System in Sepsis / 결핵

BACKGROUND: The index which could predict the prognosis of critically ill patients is needed to find out high risk patients and to individualize their treatment. The APACHE III scoring system was established in 1991, but there has been only a few studies concerning its prognostic value. We wanted to know whether the APACHE III scores have prognostic value in discriminating survivors from nonsurvivors in sepsis. METHODS: In 48 patients meeting the Bones criteria for sepsis, we retrospectively surveyed the day 1 (Dl), day 2(D2) and day 3(D3) scores of patients who were admitted to intensive care unit. The scores of the sepsis survivors and nonsurvivors were compared in respect to the Dl score, and also in respect to the changes of the updated D2 and D3 scores. RESULTS: 1) Of the 48 sepsis patients, 21(43.5%) survived and 27(56.5%) died. The nonsurvivors were older(62.7+/-12.6 vs 51.1+/-18.1 yrs), presented with lower mean arterial pressure(56.9+/-26.2 vs 67.7 +/-14.2 mmHg) and showed greater number of multisystem organ failure(1.2+/-0.8 vs 0.2+/-0.4) than the survivors(p <0.05, respectively). There were no significant differences in sex and initial body temperature between the two groups. 2) The Dl score was lower in the survivors (n=21) than in the nonsurvivors (44.1 +/-14.6, 78.5+/- 18.6, p=0.0001). The D2 and D3 scores significantly decreased in the survivors (Dl vs D2, 44.1+/- 14.6: 37.9+/-15.0, p=0.035; D2 vs D3, 37.9+/-15.0: 30.1 +/-9.3, p=0.0001) but showed a tendency to increase in the nonsurvivors (Dl vs D2 (n=21), 78.5+/-18.6: 81.3+/-23.0, p=0.1337; D2 vs D3 (n=11), 68.2+/-19.3: 75.3+/-18.8, p=0.0078). 3) The D1 scores of 12 survivors and 6 nonsurvivors were in the same range of 42~67 (mean D1 score, 53.8+/-10.0 in the survivors, 55.3+/-10.3 in the nonsurvivors). The age, sex, initial body temperature, and mean arterial pressure were not different between the two groups. In this group, however, D2 and D3 was significantly decreased in the survivors(Dl vs D2, 53.3+/-10.0: 43.6+/- 16.4, p=0.0278; D2 vs D3, 43.6+/-16.4: 31.2+/-10.3, p=0.0005), but showed a tendency to increase in the nonsurvivors(Dl vs D2 (n=6), 55.3+/-10.3:66.7+/-13.9, p=0.1562; D2 vs D3 (n=4), 64.0+/- 16.4:74.3+/-18.6, p=0.1250). Among the individual items of the first day APACHE III score, only the score of respiratory rate was capable of discriminating the nonsurvivors from the survivors (5.5 +/-2.9 vs 1.9+/-3.7, p=0.046) in this group. CONCLUSION: In sepsis, nonsurvivors had higher first day APACHE III score and their updated scores on the following days failed to decline but showed a tendency to increase. Survivors, on the other hand, had lower first day score and showed decline in the updated APACHE scores. These results suggest that the first day and daily updated APACHE III scores are useful in predicting the outcome and assessing the response to management in patients with sepsis.

The Effect of Resuscitation Fluids on the Gut Mucosa Oxygenation in Hemorrhaged Cats / 대한마취과학회지

Recently, much attention has been paid to the gut mucosal oxygenation in shock resuscitation, because many studies has been reported that the ultimate etiologies of death due to shock are mainly due to multiple organ failure caused by translocation of endotoxins and microorganisms from the ischemic gut mucosa. As there has been persistent controvesies over the relative merits of various kinds of resuscitation fluids in regard to the tissue oxygenation during management of shock, we studied the effects of various kinds of resuscitation fluids on the gut mucosal oxygenation with cats which were in hemorrhagic shcok 24 anesthetized cats were subjected to ge to decrease the mean arterial blood pressure to 40~45 mmHg and this pressure was maintained for 120 minutes (oligemic period). After this period, normal saline, hydroxyethyl starch and hypertonic saline/dextran mixture were administered respectively to raise systolic blood pressure up to 85 mmHg over 30 minutes and this level was maintained for another 120 minutes (post-oligemic period). Mesenteric venous oxygen tension, mesenteric venous-arterial lactate difference, carbon dioxide tension difference and arterial-venous pH difference were measured far evaluating the effects of three groups of resucitation fluids in regard to the gut mucosal oxygenation. There were no statistical significances among three groups by measuring the venous oxygen tension, venous-arterial carbon dioxide difference, arterial-venous pH difference. But venousarterial lactate difference in normal saline resuscitation group was significantly elevated from 5.0 +/-l.l mg/dl immediately after fluid resuscitation to 8.4+/-1.8 mg/dl 1 hour after fluid resuscitation (p<0.05). The difference in normal saline group was significantly high compared to the hydroxyethyl starch group which was 4.4+/-0.5 mg/dl and also compared to the hypertonic saline/dextran mixture group which was 4.1+/-0.9 mg/dl (p<0.05). Hydroxyethly starch and hypertonic saline/dextran mixture are more effective than normal saline in regard to the gut mucosal oxygenation in shock resuscitation, based on changes in venous-arterial lactate difference in each group. Further clinical studies may be needad.

Effects of Volume of Water taken with Oral Diazepam Premedication on Gastric Volume, pH and Anxiety / 대한마취과학회지

There is no information on the effects of variable amounts of water given less than 2 hour before induction of general anesthesia, although most patients receive oral premedication at that time. We have studied the effect of the volume of water which should accompany diazepam 0.2 mg/kg oral premedication given 90 minutes before induction of anesthesia in 75 patients undergoing elective laparoscopic cholecystectomy. The patients, ASA physical status I, randomly assigned to one of five groups. Fifteen patients were received no premedication (group A), 15 patients 50 ml (group B), 15 patients 100 ml (group C), 15 patients 150 ml (group D), and 15 patients 200 ml of water (group E). Immediately following induction of anesthesia the gastric fluid was obtained by suction on a nasogastric tube and its volume and pH were measured. Gastric fluid volume showed no statistically significant differences among the groups. Values for pH among the groups were also similar. All premedication groups reported a reduction in thirst after water intake, while only group D reported significant anxiolysis. We conclude that 150 ml is the ideal amount of water given with oral prnedication 90 minutes before general anesthesia.

Effect of Nimodipine on Incomplete Global Cerebral Ischemia-Reperfusion with prior Hyperglycemia: in vivo 31P Magnetic Resonance Spectroscopic Study in Cats / 대한마취과학회지

In vivo 31P magnetic resonance spectroscopy (MRS) was used to evaluate the effect of nimodipine on changes of [H] (pH) and the ratio of [PCr]/[Pi] in cats subjected to an incomplete global cerebral ischemia-reperfusion under the pretreated condition of hyperglycemia. Animals were subjected to a transient (18 minutes) incomplete global cerebral ischemia; the systemic arterial hypotension was induced, and immediately followed by the bilateral carotid artery ligation. Twenty cats were divided into 3 groups; for group 1 (control), 7 cats were employed for a control group; for group 2 (hyperglycemia), 7 cats were a hyperglycemia group with infusion of 50% glucose prior to ischemia; for group 3 (Nimodipine), 6 cats were infused with 50% glucose prior to ischemia, and nimodipine after ischemia. The time course of changes in pH and [PCr]/ [Pi] was monitored before, during and after ischemia. The pH decreased immediately after ischemia in all three groups. After the reperfusion was made, the values of the pH did not retum to the baseline value for the group 2 (hyperglycemia) and 3 (nimodipine), in contrary to the group 1 (control). The ratio of [PCr]/[Pi] was dropped to 20% of the baseline value after ischemia in all three groups. The value was recovered progres- sively during reperfusion period for group 1 (control), whereas for group 2 (hyperglycemia) and group 3 (Nimodipine) the values were remained depressed. The results suggest that the condition of hyperglycemia induced by the infusion of 50% glucose prior to the incomplete global cerebral ischemia-reperfusion, may deteriorate the cerebral ischemia and the infusion of nimodipine during ischemia-reperfusion has no beneficial effects to improve the cerebral acidosis and the metabolic recovery.

Prediction of Hemodynamic Changes during Enflurane Anesthesia by Preoperative Autonomic Tests in Clonidine Premedicated Patients / 대한마취과학회지

Clonidine, an a2-adrenergic agonist, has sedative and analgesic properties and reduces the inhalation anesthetic requirement and modifies the hemodynamic responses to surgery. But occasionally, severe bradycardia and hypotensian during inhalation anesthesia develops following oral clonidine premedication. To predict intraoperative hemodynamic changes during enflurane anesthesia, author evaluated noninvasive autonomic tests consisted of respiratory sinus arrhythmia (RSA), Valsalva's maneuver (VSV), R-R interval difference in head up tilt (HTR) and diastolic blood pressure difference in head up tilt (HTP) in fifty-one patients (ASA physical status I~II ) scheduled for elective surgery. Patients were received 5 ug/kg of oral clonidine at 90 min before operation. Anesthesia was maintained with enflurane, oxygen (2 liter/min) and nitrous oxide (2 liter /min). The enflurane concentration was controlled to maintain blood pressure within +/-20% of preinduction value. After anesthesia, patients were allocated to two groups according to above and below 0.5 MAC (0.84 vo1%) enflurane concentration. Each preoperative autonomic test results revealed significant correlation with heart rate (HR), mean arterial pressure (MAP), and enflurane concentration (EC), respectively (p<0.05). Values of RSA, HTR, HTP, MAP and HH wm 81+/-14.4 ms, 76+/-43.5 ms, -6+/-5.2 mmHg, 76+6.4 mmHg and 63+/-5.5 beats/min, respectively in below 0.5 MAC enflurane concentration group and were significantly different from values of RSA; 16933.7 ms, HTR; 175+/-41.7 ms, HTP; 6+/-3.1 mmHg, MAP; 90+/-11.0 mmHg and HR; 76+/-7.6 beats/min in above 0.5 MAC enflurane concen- tration group (p<0.05). In conclusion, the simple noninvasive autonomic tests are recommended in prediction of intra-operative hemodynamic changes during enflurane anesthesia when oral clonidine premedication is indicated.

Effect of Nimodipine on Incomplete Global Cerebral Ischemia-Reperfusion with prior Hyperglycemia: in vivo 31P Magnetic Resonance Spectroscopic Study in Cats / 대한마취과학회지

In vivo 31P magnetic resonance spectroscopy (MRS) was used to evaluate the effect of nimodipine on changes of [H] (pH) and the ratio of [PCr]/[Pi] in cats subjected to an incomplete global cerebral ischemia-reperfusion under the pretreated condition of hyperglycemia. Animals were subjected to a transient (18 minutes) incomplete global cerebral ischemia; the systemic arterial hypotension was induced, and immediately followed by the bilateral carotid artery ligation. Twenty cats were divided into 3 groups; for group 1 (control), 7 cats were employed for a control group; for group 2 (hyperglycemia), 7 cats were a hyperglycemia group with infusion of 50% glucose prior to ischemia; for group 3 (Nimodipine), 6 cats were infused with 50% glucose prior to ischemia, and nimodipine after ischemia. The time course of changes in pH and [PCr]/ [Pi] was monitored before, during and after ischemia. The pH decreased immediately after ischemia in all three groups. After the reperfusion was made, the values of the pH did not retum to the baseline value for the group 2 (hyperglycemia) and 3 (nimodipine), in contrary to the group 1 (control). The ratio of [PCr]/[Pi] was dropped to 20% of the baseline value after ischemia in all three groups. The value was recovered progres- sively during reperfusion period for group 1 (control), whereas for group 2 (hyperglycemia) and group 3 (Nimodipine) the values were remained depressed. The results suggest that the condition of hyperglycemia induced by the infusion of 50% glucose prior to the incomplete global cerebral ischemia-reperfusion, may deteriorate the cerebral ischemia and the infusion of nimodipine during ischemia-reperfusion has no beneficial effects to improve the cerebral acidosis and the metabolic recovery.

Prediction of Hemodynamic Changes during Enflurane Anesthesia by Preoperative Autonomic Tests in Clonidine Premedicated Patients / 대한마취과학회지

Clonidine, an a2-adrenergic agonist, has sedative and analgesic properties and reduces the inhalation anesthetic requirement and modifies the hemodynamic responses to surgery. But occasionally, severe bradycardia and hypotensian during inhalation anesthesia develops following oral clonidine premedication. To predict intraoperative hemodynamic changes during enflurane anesthesia, author evaluated noninvasive autonomic tests consisted of respiratory sinus arrhythmia (RSA), Valsalva's maneuver (VSV), R-R interval difference in head up tilt (HTR) and diastolic blood pressure difference in head up tilt (HTP) in fifty-one patients (ASA physical status I~II ) scheduled for elective surgery. Patients were received 5 ug/kg of oral clonidine at 90 min before operation. Anesthesia was maintained with enflurane, oxygen (2 liter/min) and nitrous oxide (2 liter /min). The enflurane concentration was controlled to maintain blood pressure within +/-20% of preinduction value. After anesthesia, patients were allocated to two groups according to above and below 0.5 MAC (0.84 vo1%) enflurane concentration. Each preoperative autonomic test results revealed significant correlation with heart rate (HR), mean arterial pressure (MAP), and enflurane concentration (EC), respectively (p<0.05). Values of RSA, HTR, HTP, MAP and HH wm 81+/-14.4 ms, 76+/-43.5 ms, -6+/-5.2 mmHg, 76+6.4 mmHg and 63+/-5.5 beats/min, respectively in below 0.5 MAC enflurane concentration group and were significantly different from values of RSA; 16933.7 ms, HTR; 175+/-41.7 ms, HTP; 6+/-3.1 mmHg, MAP; 90+/-11.0 mmHg and HR; 76+/-7.6 beats/min in above 0.5 MAC enflurane concen- tration group (p<0.05). In conclusion, the simple noninvasive autonomic tests are recommended in prediction of intra-operative hemodynamic changes during enflurane anesthesia when oral clonidine premedication is indicated.

A Comparison of Clinical Efficacy of Weaning Method Between the Mode of Intermittent Mandatory Ventilation and Intermittent Mandatory Ventilation Plus Pressure Support / 결핵

BACKGROUND: Pressure support ventilation(PSV) is a new form of mechanical ventilatory support that assists spontaneous inspiratory effort of an intubated patient with a clinician-selected amount of positive airway pressure. Low level pressure support during inspiration can overcome the resistive component of inspiratory work imposed by ah endotracheal tube. However the clinical efficacy of PSV as a weaning method has not been established yet. Object : The aim of study was to evaluate the efficacy of PSV when it is added to intermittent mandatory ventilation (IMV) in facilitating weaning process compared to IMV mode alone. METHOD: When the subject patients became clinically stable with their arterial blood gas analysis in acceptable range, they underwent weaning process either by IMV alone or by IMV plus PSV. The level of pressure support was held constant through the weaning period. For the patients who required mechanical ventilation for less than 72hr, 2h weaning trial was performed with IMV rate starting from 6/min. For the patients who required mechanical ventilation more than 72 hr, 7 hr weaning retrial was performed with IMV rate starting from 8/min. For the patients who failed three consecutive trials of weaning, retrial of weaning was attempted over 3 days with IMV rate starting from 8/min. Clinical characteristics, APACHE II score and nutritional status were compared. For all patients, heart rate, mean blood pressure and respiratory rate were mornitored for 48 hrs after weaning trial started. RESULTS: The total number of weaning trial was 37 in 23 patients(18 by IMV, 19 by IMV+PSV). Total ventilation time, APACHE II score and nutritional status were not statistically different between the two groups. The weaning success rate were not statistically different(38.3% by IMV, 42.1% by IMV+PSV) and the changes of mean blood pressure, heart rate, respiratory rate during first 48 hours were not different between the two groups. CONCLUSION: Low level PSV when added to IMV for weaning trial does not seem to improve the success rate of weaning from mechanical ventilation. PSV at 10cm H2O did not induce significant physiologic changes during weaning process.

Effects of Pentoxifylline on Hemorrhagic Shock in Cats / 대한마취과학회지

It was reported that pentoxifylline(PTX) improved tissue oxygenation and increased survival rate in animal models of hemorrhagic shock. The authors investigated the salutary effects of PTX on hemodynamics, oxygen transport and tissue metabolism in animal models of hemorrhagic shock. 18 anesthetized cats were subjected to hemorrhage to MABP of 40-45 mmHg and this pressure was maintained for 120 minutes. After this period, normal saline was administered in a volume double the original shed blood volume over 30 minutes. Thereafter the cats were observed for 120 minutes. Drug-treated cats received at 25 mg/kg i.v. bolus of PTX at the beginning of hemorrhage, followed by a continuous infusion of 25 mg/kg/hr throughout the experiment. PTX had no effect on MABP, pH(a-cv), P(cv-a) CO2 and lactic acid value but, PTX group had more rapid HR and higher PcvO, than placebo group(P<0.05). In addition, we found that pH(a-cv) and P(cv-a) CO2 changes occurred more rapidly than lactic acid changes(P<0.05) after hemorrhagic shock. So, pH(a-cv) and P(cv-a) CO2 changes might be considered as useful parameters for early detection of derangement of tissue oxygenation in shock states. It was concluded that PTX had no effects on indices of representing tissue oxygenation except improvement of central venous oxygen tension in this feline hemorrhagic shock model. Further studies are needed.

Comparison of Right Atrium to Pulmonary Artery Oxygen Saturation During Hemorrhagic Shock , Resuscitation , and Hypoxia in Anesthetized Cats / 대한마취과학회지

Because central venous O2 saturation (superior vena cava, ScvO2) can be monitored with less risk of the patients than mixed venous O2 saturation (pulmonary artery, SvO2), there have been studies to see if ScvO2 could replace SvO2. But previous studies showed that these two measurements were correlated but "not interchangeable. Therefore the authors compared right atrial C#b saturation (SraO2) with S vO2 over a wide range of cardiorespiratory status including control, hemorrhage, resuscitation, and hypoxia in anesthetized cats. We performed thoracotomy and inserted cannulae directly into the right atrium and the pulmonary artery. Blood sampling were obtained synchronously through the cannulae and tested immediately. The correlation coefficients in control, hemorrhage, resuscitation, and hypoxia groups were 0.876, 0.794, 0.946, 0.948 respectively and the two measurements in each group showed statistically significant correlations (p<0.05). But the biases of the two measurements in each group were 0.11+/-2.9, 0.35+/-4.2, -0.55+/-3.2, 0.23+/-4.2 respectively and the limits of agreement ( 2 standard deviation) in all groups exceeded permissible (5%) to conclude that the two measurements were in agreement. Thus, we reached the conclusion that the absolute values of SraO2, though not being sufficiently identical to S vO2 to calculate O2 uptake or pulmonary shunt precisely, can reflect the S vO2 trend following the O2 supply / demand change. Further clinical studies are needed.

Effects of Oral Clonidine on Cardiovascular Response to Tracheal Intubation / 대한마취과학회지

Induction of general anesthesia with tracheal intubation is routine proeedure but causes varying degrees of sympathetic stimulation such as increases in blood pressure and heart rate. Many approaches have been tried to attenuate these hemodynamic responses To evaluate the effects of clonidine, a-2 adrenergic receptor agonist, on the hemodynamic changes induced by intubation, we administered clonidine(5 ug/kg, P.O.) 90 minutes before induction of anesthesia. We measured systolic pressure, diastolic pressure and heart rate before premedication, before induction, after intubation and 5, 10 minutes after intubation and compared with control group. The results were as follows: 1) After intubation systolic and diastolic blood pressures increased significantly in both group(P<0.05) but the increasing rate was significantly less than in clonidine group. (P<0.05) 2) After intubation the increaae in heart rate in clonidine group was significantly less than in control group (p<0.05). 3) The trend of increase in heart rate in clonidine group was more stabilized than control group. 4) Systolic blood pressure and heart rate in clonidine group were significantly decreased in preinduction period after premedication.

Pulmonary Artery Catheterization and Mixed Venous Oximetry / 대한마취과학회지

No abstract available.

Nosocomial pneumonia in medico-surgical intensive care unit

Cases of hospital acquired pneumonia occurring during the 1st 12 months of Medico-Surgical ICU (Intensive care unit, MSICU) in operation were evaluated retrospectively to determine its incidence, common causative pathogens, outcome and radiological patterns with the new hospital setting providing a unique relatively aseptic environment. Among the 920 admitted patients, 73 episodes of nosocomial pneumonia on 63 patients were identified and the incidence rate was 7%. The most common pathogens were Pseudomonas. Staphylococcus, Serratia, and Enterobacter in the order of frequency of occurrence, and the gram-negative pathogens comprised 70%. Nosocomial pneumonia was more common after use of antibiotics due to such pathogens as Enterobacter, Acinetobacter, and Candida which caused poor outcome. Enterobacter had the greatest tendency to be related with poor outcome and Serratia the least. Overall mortality was 25%. Bronchopneumonia was the most common type of pneumonia caused by any pathogen except Acinetobacter which caused a mixed type of nosocomial pneumonia.

Intermittent Labetalol Injections for Hypotensive Anesthesia during Clipping of Cerebral Aneurysm 4 Cases / 대한마취과학회지

Hypotensive anesthesia is still widely employed during neurosurgery in spite of the development of microsurgical techniques. There have been a few reports regarding cerebral blood flow during injections of labetalol, a non-selective beta and selective alpha 1-blocker, to control blood pressure during or after craniotomy and results were favorable. In 4 cases, intermittent labetalol injections were given for hypotensive anesthesia during clipping of a cerebral aneurysm and the results were as follows: 1) The onset was within 1-2 minutes after injection. 2) Hypotensive anesthesia was well maintained by repeated injections during surgery. 3) Systolic and mean arterial blood pressure were decreased as much as 35.7 mmHg and 24.3 mmHg respectively. 4) Heart rate did not change significantly. 5) After clipping, blood pressure returned to the previous level with atorpine or ephedrine. 6) We conclude that labetalol can be an excellent choice for hypotensive anesthesia.