Estimating the effect of bystander-initiated cardiopulmonary resuscitation in Japan

Low incidence of bystander-initiated cardiopulmonary resuscitation (CPR) is allegedly responsible for poor survival from out-of-hospital cardiac arrest (OHCA) in Japan. This study was conducted to determine significant predictors for survival after collapse-witnessed OHCA of presumed cardiac etiology to investigate the impact of bystander-initiated CPR. Logistic regression analysis of OHCA of presumed cardiac etiology was performed on retrospective data sets from three Japanese suburban communities. All arrest incidents were witnessed and occurred prior to the arrival of EMS personnel. Outcome measure was survival to discharge. Initial electrocardiogram (ECG) rhythm (ventricular fibrillation (VF) or not), interval from collapse to CPR (within 5 min or not), and initial ECG rhythm/collapse-to-CPR interval interaction were significantly associated with survival. Patient age (70 years or less/over 70 years), interval from collapse to EMS response, and bystander-initiated CPR were significantly associated with VF in an initial ECG. The effectiveness of bystander-initiated CPR for OHCA can be successfully predicted based on the interval from collapse to CPR and initial ECG rhythm. The increase in the proportion of bystander-initiated CPR from the present level of 20-50% would be expected to rescue another 1800 victims of OHCA per year in Japan.

A Utstein-style analysis of prognostic factors related to survival in out-of-hospital cardiac arrests in Akita-City, Japan

To analyze the epidemiology of out-of-hospital cardiac arrests and to elucidate modifiable factors affecting survival, we conducted a prospective cohort study in a middle-sized urban city served by a single emergency medical service (EMS) system in which emergency medical technicians use an automated external defibrillator. Data were collected from out-of-hospital cardiac arrests occurring between 1 January, 1994 and 31 December, 1998 by applying the Utstein style. The main outcome measure was survival at 1 year after hospital discharge. The overall incidence of out-of-hospital cardiac arrest was 71.7/100 000 inhabitants/year. Resuscitations were attempted in 762 of 1118 patients with confirmed cardiac arrest. Of the 762 patients, 37 (4.86%) survived. The cause of cardiac arrest was presumed to be cardiac in 340 (44.6%). Of the 340 cardiac arrests, 180 (52.9%) were witnessed by bystanders. Ventricular fibrillation (VF) was recorded as an initial rhythm in 56 (31.1%) of the 180 patients, and cardiopulmonary resuscitation (CPR) was performed by bystanders in 89 (49.4%). The survival rate was 39.2% (22/56) when cardiac arrest was bystander-witnessed and of cardiac origin with VF as an initial rhythm. VF as an initial rhythm, age of the patients and intervals of call-to-first CPR attempt and collapse-to-arrival at patient's side were major factors relating to survival in the witnessed cardiac arrests of cardiac origin. The age, and gender of the patients, place of collapse and intervals of collapse-to-first CPR and collapse-to-arrival at patient's side were representative factors affecting the incidence of VF as an initial rhythm. The survival rate in Akita-City from bystander-witnessed cardiac arrests of cardiac origin with VF as an initial rhythm was comparable to those in other regions with advanced EMS systems. However, the incidence of VF as an initial rhythm is extremely low. Reduction of intervals of call (collapse)-to-first CPR attempt and collapse-to-arrival at patient's side or authorization of use of automated external defibrillator in basic life support may increase the incidence of VF as an initial rhythm and improve the survival from witnessed cardiac arrests with cardiac origin.

Systemic hypotensive response to protamine following chronic inhibition of nitric oxide synthase in rats

PURPOSE

The aims of the present studies were to determine whether the systemic hypotensive response to protamine was modified in rats pre-treated for two weeks with the nitric oxide synthase inhibitor, NG-nitro-L-arginine-methyl ester (L-NAME), and to evaluate the inhibitory effect of heparin on the systemic hypotensive response to protamine in vivo.

METHODS

Male rats were randomly assigned into four groups. Normal saline 12 microliters.day-1, D-NAME (an inactive enantiomer of L-NAME), 10 mg.kg-1, L-NAME, 1 or 10 mg.kg-1.day-1 i.p. was administered for two weeks and the haemodynamic changes were measured after protamine administration. In another experiment, male rats were assigned to two groups. In one, the heparin group, protamine was administered after heparin had been administered and in the other, protamine group, protamine alone was administered.

RESULTS

L-NAME inhibited the decrease in systemic arterial pressure after protamine administration (P < 0.05), but D-NAME had no effect. Also, heparin reduced the decrease in systemic arterial pressure after protamine (P < 0.05).

CONCLUSION

Nitric oxide is mainly responsible for mediation of the systemic hypotensive response to protamine which is also reduced by heparin.

Platelet-activating factor is a key mediator of pulmonary vasoconstriction and bronchoconstriction after antigen challenge in the perfused sensitized rabbit lung

Exposure of sensitized perfused rabbit lungs to human O-N type erythrocytes leads to pulmonary vasoconstriction and bronchoconstriction. To investigate whether platelet-activating factor (PAF) is a mediator of pulmonary vasoconstrictive and bronchoconstrictive responses after antigen challenge, we administered antigenic erythrocytes after the administration of PAF antagonist (.1 mg/kg; CV6209). Pulmonary arterial and airway pressures significantly increased after antigen challenge in the sensitized rabbit lungs, but not in the nonsensitized rabbit lungs. CV6209 significantly inhibited these pulmonary vasoconstrictive and bronchoconstrictive responses after antigen challenge. We concluded that PAF, at least in part, plays an important role in pulmonary vasoconstriction and bronchoconstriction after antigen challenge in rabbits.

[Repeated administration of protamine attenuates protamine-induced systemic hypotension]

Protamine may act on endothelial cell receptors to stimulate the production of nitric oxide, which would promote vasodilation. If so, the repeated administration of protamine may attenuate protamine-induced systemic hypotension. To confirm this hypothesis, we examined whether repeated administration of protamine attenuates protamine-induced systemic hypotension in rats. Rats were divided into two groups. In bolus injection group (S group), protamine was given intravenously at 10 mg.kg-1. In repeated administered group (R group), the same dose of protamine was given intravenously 30 min after continuous infusion of protamine 10 mg.kg-1. The mean arterial pressure in S group decreased significantly after administration of protamine, compared with R group. Also, maximal decrease rate of the arterial pressure after administration of protamine in R group was significantly lower than in S group. These results demonstrate that repeated administration of protamine attenuates protamine-induced systemic hypotension. We confirm the hypothesis that protamine will release nitric oxide by binding with the receptor on the endothelium in the vessel and subsequently cause systemic hypotension.

Chronic interleukin-2 treatment in awake sheep causes minimal or no injury to the lung microvascular barrier

Interleukin-2 (IL-2) is reputed to cause a "vascular leak syndrome." We studied pulmonary hemodynamics and lymph dynamics in six sheep treated for 7 days with IL-2 (1.8 million IU/kg twice daily or 1.8 million IU/kg each day as a continuous infusion). Lung lymph flow increased from 4.8 +/- 2 ml/15 min pre-IL-2 to 14.4 +/- 6.8 ml/15 min on the seventh day of IL-2. The lymph-to-plasma protein concentration ratio was unchanged (0.70 +/- 0.06 vs. 0.63 +/- 0.13). The plasma-to-lymph equilibration half-time of radiolabeled albumin was 2.0 +/- 0.6 h pre-IL-2 and 1.0 +/- 0.7 h on day 7 of IL-2. Pulmonary arterial pressure was 24 +/- 7 cmH2O pre-IL-2, increased to 32 +/- 4 cmH2O on the fourth day of IL-2, and returned to 29 +/- 5 cmH2O on the seventh day of IL-2. Extravascular lung water was normal (4.07 +/- 0.25 g/g dry lung). To clearly determine whether the increase in lung lymph flow was due to hemodynamic changes or to increased leakiness of the microvascular barrier, we volume loaded six sheep with lactated Ringer solution before and after 3 days of IL-2 treatment (1.8 million IU/kg twice daily). Lung lymph flows increased fivefold during 4 h of crystalloid infusion compared with baseline and were higher after 3 days of IL-2. However, lymph-to-plasma protein concentration ratios decreased to the same low levels pre-and post IL-2 (0.39 +/- 0.06 vs. 0.41 +/- 0.10), indicating and intact microvascular barrier. Extravascular lung water was elevated (5.56 +/- 0.39 g/g dry lung) but was not different from lung water in three volume-loaded control sheep (4.87 +/- 0.53 g/G dry lung). We conclude that IL-2 causes minimal or no injury to the pulmonary microvascular barrier and that volume expansion during IL-2 treatment can cause hydrostatic pulmonary edema.

Thromboxane rather than platelet activating factor mediates pulmonary vasoconstriction after antigen challenge in rabbits

To investigate whether thromboxane and/or platelet activating factor (PAF) mediate the pulmonary vasoconstrictive response to antigen in vivo, we intra-arterially injected human erythrocytes as antigen into sensitized rabbits after administration of putative inhibitors: a cyclooxygenase synthetase inhibitor (indomethacin, 5 mg.kg-1), a thromboxane synthetase inhibitor (OKY 046, 10 mg.kg-1 + 100 micrograms.kg-1.min-1), and a PAF blocker (CV6209, .1 mg.kg-1). Pulmonary artery and airway pressures significantly increased after the antigen challenge in sensitized rabbits, but did not in nonsensitized rabbits. Both indomethacin and OKY046 significantly inhibited the increase in pulmonary artery pressure after the antigen challenge, while CV6209 did not. CV6209 significantly attenuated the decrease in femoral artery pressure after the antigen challenge, while neither indomethacin nor OKY046 did. There were no significant differences in the increase in airway pressure among the groups. We conclude that thromboxane rather than PAF mediates the pulmonary vasoconstriction after the antigen challenge and that mediators other than thromboxane and PAF mediate bronchoconstriction after the antigen challenge in sensitized rabbits.

Dibutyryl cAMP improves systemic vasoconstriction caused by endotoxin in dogs

We studied whether dibutyryl cyclic adenosine monophosphate (DbcAMP), which freely penetrates into the cells, improves systemic vasoconstriction caused by endotoxin in dogs. Thirteen anesthetized dogs were randomized into three groups. The endotoxin (ETX) group (n = 5) received only Escherichia coli endotoxin (3 mg.kg-1, intravenously). The ETX + DbcAMP group (n =5) received DbcAMP (6 mg.kg-1, intravenously) 30 min before the administration of endotoxin. The DbcAMP group received the same dose of DbcAMP 30 min after administration of saline. In the ETX group, systemic blood pressure and cardiac index significantly decreased, and systemic vascular resistance significantly increased, while in the ETX + DbcAMP group, increases in systemic and pulmonary vascular resistances after the administration of endotoxin were attenuated. DbcAMP did not cause hemodynamic changes in normal dogs. Plasma concentrations in thromboxane B2 in the ETX group were higher than in the ETX + DbcAMP group. Also, the change in plasma cyclic AMP concentrations showed a good logarithmic correlation with the change in plasma thromboxane B2 concentrations after the administration of endotoxin (r = .908, log (delta T x B2) = -.002* (delta cAMP) + 3.786). We conclude that DbcAMP improves systemic vasoconstriction caused by endotoxin in dogs. The beneficial mechanism of DbcAMP on systemic vasoconstriction after the administration of endotoxin may be partially due to inhibition of thromboxane B2.

[Effect of sevoflurane on release of TNF-alpha and IL-1 beta from human monocytes]

Although isoflurane inhibits TNF-alpha and IL-1 beta release from human monocytes stimulated by LPS in dose dependent fashion, it is unclear whether sevoflurane has the same effects. Therefore, we investigated whether sevoflurane could inhibit TNF-alpha and IL-1 beta secretions from human monocytes stimulated by LPS in dose dependent fashion in vitro. Human monocytes stimulated by LPS were cultured for 3 h in the presence of sevoflurane 1% or 5%. Another group of human monocytes were cultured in the absence of sevoflurane. TNF-alpha and IL-1 beta increased after stimulation of LPS and these increases were not inhibited by sevoflurane in a dose dependent fashion. We conclude that sevoflurane does not inhibit TNF-alpha and IL-1 beta release from monocytes stimulated by LPS.

Pulmonary responses to heparin-protamine complexes: the effects of age and species

To test the hypothesis that heparin-protamine complexes (H-P complexes) react with pulmonary intravascular macrophages, we studied the difference in the pulmonary reaction to H-P complexes between goats and rabbits and among different-aged goats. The increases in pulmonary arterial pressure (Ppa) and plasma thromboxane levels (Tx) after injection of H-P complexes (1.2 ml/kg) in goats (delta Ppa = 17 +/- 7.0 mmHg, delta Tx = 17.3 +/- 10.1 ng/ml) were significantly greater than in rabbits (delta Ppa = 0.50 +/- 1.0 mmHg, delta Tx = -0.01 +/- 0.17 ng/ml), the increase in Ppa in adult goats (> 150 days old; delta Ppa = 17 +/- 7.0 mmHg) was about sixfold higher than in newborn goats (1-3 days old; delta Ppa = 2.8 +/- 4.0 mmHg), and the increase in Tx in adult goats (delta Tx = 17.3 +/- 10.1 ng/ml) was significantly greater than those in newborn and young (19 days old) goats (delta Tx = 0.69 +/- 0.48 and 3.60 +/- 0.36 ng/ml, respectively). The pulmonary hemodynamic reaction to H-P complexes is consistent with the concept that the H-P complexes react with pulmonary intravascular macrophages.

Inhibition of pulmonary hypertensive response after antigen challenge

By adding antigen cells into perfusate circulation, a great increase in pulmonary arterial pressure was observed in isolated perfused lung from rabbits previously immunized with human O-N type erythrocytes. To investigate whether thromboxane A2 is the main mediator in pulmonary vasoconstrictive response, we injected antigen erythrocytes into the reservoir after administration of putative inhibition as follows: indomethacin (5 mg/kg, thromboxane A2 synthetase inhibitor), KT2-962 (.1 mg/kg, thromboxane receptor blocker), and pyrilamine (.1 mumol, H1 blocker). Pulmonary vasoconstrictive response after antigen challenge was significantly blocked by both indomethacin and KT2-962, but not by H1 blocker. Although the H1 blocker, pyrilamine, did not significantly block the pulmonary vasoconstrictive response, it did significantly block the bronchoconstrictive response after antigen challenge; however, the bronchoconstrictive response was not blocked by either indomethacin or KT2-962. We conclude that thromboxane is the main mediator in the pulmonary vasoconstrictive response, and histamine is the main mediator in the bronchoconstrictive response.

Heparin-protamine complexes cause pulmonary hypertension in goats

BACKGROUND

Protamine reversal of heparin-induced anticoagulation causes thromboxane release followed by pulmonary vasoconstriction in sheep and pigs. The aim of this study was to determine whether heparin-protamine (H-P) complexes are causative agents of thromboxane release followed by pulmonary hypertension associated with protamine reversal of heparin.

METHODS

We separated H-P complexes and non-heparin-protamine (non-H-P) complexes from heparinized defibrinated human plasma neutralized with protamine by chromatography and studied the changes in hemodynamics, airway pressure, and thromboxane B2 concentration after injection of H-P complexes or non-H-P complexes into seven goats. In addition, we studied whether these pulmonary responses were blocked in goats pretreated with cyclooxgenase inhibitor (Indomethacin, n = 5) or thromboxane synthetase inhibitor (OKY-046, n = 5).

RESULTS

A very small dose of H-P complexes increased pulmonary arterial and peak airway pressures and was followed by thromboxane B2 release (from 12 [5.5-23] to 28 [16-44] mmHg, from 9.0 [7.5-15] to 12 [8-19] cmH2O, and from 0.85 [0.34-3.2] to 16.4 [1.4-39.3] ng.ml-1, respectively). On the other hand, animals that received non-H-P complexes showed no significant changes. Indomethacin totally blocked and OKY-046 partially blocked the increases in pulmonary arterial pressure and thromboxane B2 concentration.

CONCLUSIONS

H-P complexes play a major role in pulmonary hypertension after protamine reversal of heparin, and thromboxane A2 is a main mediator of the pulmonary hypertensive response to H-P complexes in goats.

[Role of antigen-antibody reaction in pulmonary hypertensive reaction after antigen challenge]

Pulmonary arterial pressure, airway pressure, and lung weight increase were studied after antigen (human O-N type erythrocytes) challenge in isolated-perfused sensitized rabbit lungs. To investigate whether these hemodynamic changes are mainly caused by antigen-antibody reaction or by the other mechanisms, we measured changes of pulmonary arterial and airway pressures, and lung weight gain after antigen challenge in perfused nonsensitized rabbit lungs. Thirteen nonsensitized rabbits were divided into 2 groups; in N group (n = 5), antigen was given into Krebs Hanseleit perfusate; in Ab group (n = 8), antibody was given into reservoir 30 min prior to antigen challenge. Pulmonary arterial pressure in Ab group was higher than in N group after antigen challenge. Maximal increase in pulmonary arterial pressure after antigen challenge depended on agglutinin titer of antibody in perfusate (delta Ppa = 0.068 x [titer]-0.146, r2 = 0.929). However, there were no significant differences between the two groups in changes of airway pressure and lung weight gain after antigen challenge. Although agglutinin titer of perfusate in Ab group was higher than our previous study, pulmonary hypertensive reaction to antigen in Ab group was significantly lower. It is concluded that the other mechanism besides antigen-antibody reaction itself can be responsible for hemodynamic changes after antigen challenge.

[The effect of isoflurane on the secretion of TNF-alpha and IL-1 beta from LPS-stimulated human peripheral blood monocytes]

The cytokines such as tumor necrosis factor and interleukin-1 secreted from macrophages/monocytes proved to play important roles in the pathogenesis of endotoxemia, severe pancreatitis and other surgical injuries. However, it is still unclear how inhalational anesthetic agents influence the secretion of these cytokines from macrophages/monocytes. We investigated the effects of isoflurane on TNF-alpha and IL-1 beta secretions from human peripheral blood monocytes stimulated by lipopolysaccharide. TNF-alpha and IL-1 beta secretions increased after LPS stimulation and this increase was inhibited by isoflurane in dose-dependent fashion. The inhibitory action of isoflurane disappeared between 1 and 3 hours after stopping isoflurane inhalation. We concluded that isoflurane could inhibit TNF-alpha and IL-1 beta secretions from peripheral blood monocytes stimulated by LPS in a dose-dependent fashion and that the inhibitory action of isoflurane was reversible.

[Milrinone suppresses TNF-alpha and IL-1 beta release in mouse peritoneal macrophages]

Tumor necrosis factor-alpha (TNF-alpha) exerts a wide spectrum of biological activities and contributes to the pathophysiology of septic shock. We studied whether milrinone suppresses TNF-alpha and IL-1 beta releases from mouse peritoneal macrophages. Mouse peritoneal macrophages were stimulated for 18 hr with lipopolysaccharide and different doses of milrinone. TNF-alpha release was suppressed in a dose-dependent fashion with milrinone, reaching half-maximal inhibition at 30 microM. Release of IL-1 beta was not suppressed with 25 microM of milrinone, but it was suppressed with 250 microM of milrinone. We conclude that TNF-alpha release is suppressed by therapeutically administered milrinone.

[Effects of thromboxane on pulmonary arterial response to platelet activating factor in rabbit]

The aim of this study is to clarify whether thromboxane mediates hemodynamic and airway changes induced by PAF in rabbits. Rabbits were divided into 4 groups. In No group rabbits (n = 5), PAF was intravenously injected. In Indo group rabbits (n = 5), indomethacin was infused intravenously 20 min prior to PAF administration. In KT2 group rabbits (n = 4), selective thromboxane antagonist; KT2-962, or in CV group rabbits (n = 3), selective PAF antagonist; CV6209 was injected intravenously 5 min prior to PAF administration. After PAF administration, pulmonary arterial and airway pressures increased transiently, and blood pressure, and leukocyte as well as platelet counts decreased. These hemodynamic and airway changes induced by PAF were almost totally blocked by CV6209 administration, but not by indomethacin and KT2-962 administrations. Similarly, decreases in leukocyte and platelet counts induced by PAF were blocked by CV6209 and KT2-962, but not by indomethacin. We conclude that thromboxane does not mediate hemodynamic and airway changes induced by PAF. PAF is likely to directly induce these changes.

[Pulmonary hypertensive responses to erythrocytes components in sensitized rabbits]

Antigen erythrocytes cause a transient pulmonary hypertension in sensitized rabbits. We investigated the main responsible component in the antigen erythrocytes. Eleven rabbits were immunized intravenously with human O-N type erythrocytes every ten days until the agglutinin titer = 1:8,000 was obtained. Another ten rabbits without immunization served as a control group. Human erythrocytes were osmolitically hemolyzed and then separated into hemoglobin and membrane components by centrifugation. In sensitized rabbits, a bolus injection of human hemoglobin 0.7 ml.kg-1 caused increases in pulmonary arterial and airway pressures within 3-4 min. Increase in pulmonary arterial pressure after injection of hemoglobin component was significantly higher than that after injection of membrane component in sensitized rabbits. However, in nonsensitized rabbits both components were ineffective. Leukocytes counts decreased by 73-62% in sensitized rabbit, while they decreased by 16-37% in nonsensitized rabbits 5 min after injection of hemoglobin or membrane component. Platelets decreased by 54-61% in sensitized rabbits, while they decreased by 24-9% in nonsensitized rabbits 5 min after injection of hemoglobin or membrane component. We conclude that hemoglobin is the responsible component in the antigen erythrocytes and chemical mediators, such as thromboxane and platelet activating factor, may not be released from platelets and leukocytes.

[Effects of thromboxane A2 receptor antagonist, KT2-962 on pulmonary hypertensive responses to antigen challenge in isolated sensitized rabbit lung]

We investigated whether KT2-962 (thromboxane H2/A2 receptor antagonist) could attenuate increases in pulmonary arterial and airway pressures after antigen challenge in isolated-perfused sensitized rabbit lungs. Sensitized rabbits were immunized intravenously with human O-N type erythrocytes until the agglutination titer against antigen reached above 1:10,000. Nineteen rabbits were divided into three groups. In N group (n = 9), antigen was challenged into perfusate. In KT2 group (n = 5), 1 mg.kg-1 of KT2-962 was given into reservoir 10 min prior to antigen challenge. In Indo group (n = 5), 5 mg.kg-1 of indomethacin was given into reservoir 20 min prior to antigen challenge. Maximal increase in pulmonary arterial pressure after antigen challenge in N group was significantly higher than that in KT2 group or in Indo group (13.4 +/- 3.3 mmHg, 1.5 +/- 0.5mmHg, 1.5 +/- 0.2mmHg, respectively). Maximal increase in airway pressure in N group was higher than that in KT2 group or in Indo group (2.9 +/- 0.8cmH2O, 0.8 +/- 0.2cmH2O, 0.5 +/- 0.2cmH2O, respectively), but this was not significant. Pharmacological potential of KT2-962 to attenuate pulmonary hypertensive responses was estimated 50 times stronger than that of indomethacin. In conclusion, KT2-962 can exert therapeutic effect on pulmonary hypertensive responses induced by immunological reactions.

Methylmethacrylate bone cement does not release histamine in patients undergoing prosthetic replacement of the femoral head

This study was designed to see if methylmethacrylate monomer bone cement released histamine in 13 patients undergoing total hip replacement surgery with a cemented prosthesis, compared with seven control patients receiving a cementless porous-coated prosthesis. Blood samples for plasma concentrations of histamine were obtained before the start of anaesthesia, immediately before insertion of methylmethacrylate bone cement into the shaft of the femur in the cemented fixation group or before insertion of the femoral component of the prosthesis in the cementless fixation group, and 15, 30 and 60 min after the start of implantation of the prosthesis. In both groups, changes in plasma histamine did not differ significantly from baseline before implantation of cement. There were no significant differences between groups. We conclude that methylmethacrylate bone cement does not release histamine during total hip replacement surgery.

[Antigen-induced pulmonary arterial responses in the isolated perfused lung of sensitized rabbits]

To investigate whether blood components, such as complements, antibody, platelets and leukocytes, can play important roles in increasing pulmonary arterial and airway pressures after antigen challenge in sensitized rabbits, we measured the time course of pulmonary arterial pressure, airway pressure and lung weight gain after antigen challenge in isolated perfused rabbit lungs. Nineteen rabbits were divided into 3 groups; S group (n = 9), which was sensitized rabbit lung with antigen added into perfusate; NS group (n = 5), which was nonsensitized rabbit lung with antigen added into perfusate; S+R group (n = 5), which was sensitized rabbit lung with autologous erythrocytes added into perfusate. Although agglutinin titer in sensitized rabbits was more than 1: 10,000, that in the perfusate was less than 1:16. Pulmonary arterial and airway pressures significantly increased after antigen challenge in S group, while those in NS and S+R groups did not show any change. Also there were no significant changes in pulmonary arterial and airway pressures and lung weight gain in nonsensitized rabbit lungs of the same agglutinin titer as S group. Lung weight gain in S group was 2-4 times higher than that in S+R group after antigen challenge. We conclude that blood components, such as complements, antibody, platelets and leukocytes, do not play important roles on antigen induced pulmonary responses in sensitized rabbit lungs.

[Pharmacokinetics of isosorbide dinitrate studied by the extrapolation model]

To make a pharmacokinetic model of isosorbide dinitrate (ISDN), we infused ISDN at 1, 10 or 30 micrograms.kg-1.min-1 into anesthetized rabbits and measured concentrations of ISDN and its metabolites (2-ISMN and 5-ISMN) in plasma, urine and bile. We found the concentration gradient of ISDN between arteries and veins and between the ascending aorta and femoral artery. These concentration gradients may occur due to metabolism and accumulation of ISDN in many organs and tissues, let alone the vascular endothelium. There was no significant difference in plasma concentrations of ISDN or its metabolites between the hepatic vein and femoral vein. It seems that ISDN is metabolized in various organs and tissues. By ISDN infusion of more than 10 micrograms.kg-1.min-1, the plasma concentration of ISDN showed a pronounced increase. It appears that there is metabolic saturation of ISDN. Using these informations, we extrapolated the model to human and the estimated values were compared with observed values to determine the validity of the extrapolation model. There was no remarkable differences between the estimated values and observed values. This suggests the validity of the model. The plasma concentrations of ISDN, estimated by this extrapolated model, showed a linear increase (Y = 30X) with the flow rate range of 0.2-5.0 micrograms.kg-1.min-1, when the metabolic rate was normal. With ISDN infusion of more than 5.0 micrograms.kg-1.min-1, the plasma concentrations of ISDN showed a pronounced increase. In the conditions of impaired metabolism, the plasma concentrations of ISDN increase exponentially.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of age on filtration coefficient in isolated zone 3 rat perfused lungs]

To investigate the effect of age on the filtration coefficient (Kf) in isolated rat perfused lungs, we divided 18 Sprague-Dawley rats randomly into 3 groups; 1) 5 wk of age, 150 +/- 1.5g, n = 6; 2) 10 wk of age, 320 +/- 18.8g, n = 6; and 3) 14 wk of age, 460 +/- 10.0g, n = 6. We used Krebs-Henseleit solution with 5% bovine serum albumin as the perfusate and maintained perfusion using constant pressure circuit system. We calculated the filtration coefficient in isolated rat perfused lungs in zone 3 conditions (pulmonary arterial pressure > pulmonary venous pressure > alveolar pressure) using gravimetric method. The filtration coefficients in rats of 14 wk of age were 3-fold higher than those in other two groups (Kf = 5.31 +/- 0.29 mg.min-1.cmH2O-1.g-1 in 5 wk of age, 5.38 +/- 0.49 mg.min-1.cmH2O-1.g-1 in 10 wk of age and 16.17 +/- 0.46 mg.min-1.cmH2O-1.g-1 in 14 wk of ages). Also, there were a large population of leukocytes in lung of 14 wk of age, but not in 5 wk and 10 wk of age. In addition, the filtration coefficients in 5 wk and 10 wk of age were of the same magnitude as in other investigators' reports. We conclude that rat in 10 wk of age is suitable for the evaluation of the pulmonary vascular permeability.

[Prostaglandin E1 suppresses hypersecretion of antidiuretic hormone induced by surgical stress]

We studied the effects of prostaglandin E1 (PGE1) on decrease in urine output during surgery in patients for radical total hysterectomy under general anesthesia. The patients were randomly allocated into two groups. Five patients (control group) were given no PGE1 and served as control. Seven patients (PGE1 group) were given continuous infusion of PGE1 at a rate of 50 ng.kg-1 x min-1 after first measurement (baseline). Urine output in control group decreased by 68%, but in PGE1 group it did not change from the baseline. Urine sodium and fractional sodium excretion in control group decreased, but in PGE1 group they increased. Creatinine clearance increased from the baseline in both groups. Antidiuretic hormone in control group increased by 30%, but in PGE1 group decreased by 53%. Plasma renin activity, angiotensin I, angiotensin II in both groups increased, and those in the control group were higher than those in PGE1 group. However, aldosterone in the control group was lower than that in PGE1. These results indicate that diuretic effect of PGE1 could be mediated by suppression of antidiuretic hypersecretion induced by surgical stress, inhibition of the action of antidiuretic hormone, and suppression of sodium and water reabsorption in proximal and distal tubules. Also, PGE1 did not directly stimulate renin-angiotensin system.

[Prostaglandin E1 does not inhibit production of TNF and IL-1 by mononuclear cells after head-neck surgery]

We studied whether human blood mononuclear cells could produce tumor necrosis factor (TNF) and interleukin 1 (IL-1) by surgical stimuli, and if so, prostaglandin E1 (PGE1) could inhibit their increases before and following operation in patients undergoing head-neck surgery. The patients were randomly allocated into 2 groups; no PGE1 infusion group (control group, n = 6) and PGE1 infusion group (PGE1 group, n = 6). PGE1 group was infused intravenously with PGE1 at a rate of 30 ng.kg-1 x min-1 during surgery and at a rate of 10-30 ng.kg-1 x min-1 after surgery. Peripheral blood was withdrawn into heparinized syringes from these patients immediately before surgery and on the 1st postoperative day. Production of TNF on the 1st postoperative day increased 1.5 fold in control group and 1.4 fold in PGE1 group compared with those before surgery. Production of IL-1 on the 1st postoperative day increased 1.7 fold in control group and 1.1 fold in PGE1 group compared with those before surgery. Also, there were no significant differences between 2 groups in both productions of TNF and IL-1. These data indicate that human blood mononuclear cells would produce TNF and IL-1 by surgical stimuli and PGE1 could inhibit their production by surgical stimuli. It also provides evidence that PGE1 does not inhibit the body's defense response to surgical stimuli.

[Nonspecific anaphylactoid reaction in low IgE patients]

We reported two cases of anaphylactoid reaction caused by ranitidine and alprostadil. We suggest that these anaphylactoid reactions are nonspecific reactions which are observed in low IgE patients, because plasma IgE was still low 6 weeks after allergic reaction and these drugs have not been given to them before and eosinophilic and basophilic cells showed no change at all. We have to consider that there is a high risk of allergic reaction during general anesthesia, because many drugs are injected intravenously during general anesthesia.

[Postoperative disturbance of consciousness due to tumor emboli of the orifice of pulmonary artery]

We reported a case of an abrupt hypotension and hypoxemia which lasted more than 60 min due to emboli of tumor at the orifice of the pulmonary artery during operation. Although the emboli were removed under the cardiopulmonary bypass (CPB) and later the patient regained good respiratory and hemodynamic conditions, he had a disturbance of consciousness after the operation. We began oxygen hyperbaric therapy (OHP) from the 6th postoperative day under spontaneous ventilation. His consciousness improved quickly after the beginning of OHP. We conclude that OHP and CPB might be useful to treat the postoperative disturbance of consciousness due to hypotension and hypoxemia during operation.

[Effects of DbcAMP on tumor necrosis factor and interleukin-1 production in human monocytes]

Recent reports have shown that dibutyryl cAMP (DbcAMP) blocks endotoxin-induced lung injury. To determine whether DbcAMP suppresses the production of tumor necrosis factor (TNF) and interleukin-1 (IL-1) in human monocytes, we measured the levels of TNF and IL-1 in response to E. Coli lipopolysaccharide (40 micrograms.ml-1) in vitro. We now show that DbcAMP suppressed dose-dependently the production of TNF in human monocytes, and DbcAMP totally suppressed it at the dose above 5 x 10(-4) M. However, DbcAMP did not suppress the production of IL-1 even at the dose of 5 x 10(-3) M in human monocytes. These data suggest that the productive mechanism of IL-1 may be different from that of TNF. Further, suppression of TNF by DbcAMP may contribute to the beneficial effects in animal models of septic shock or lung injury and this may have clinical implications.

[Anesthetic management of a patient with HELLP syndrome with bronchial asthma]

We gave anesthesia for cesarean section to 30 year-old female with HELLP syndrome with bronchial asthma. HELLP syndrome is characterized by hemolysis, liver dysfunction and thrombocytopenia, besides syndrome of severe toxemia of pregnancy. After intubation with sevoflurane, diazepam and vecuronium, anesthesia was maintained with nitrous oxide, oxygen, sevoflurane and vecuronium, because she had an attack of bronchial asthma before operation. Though she had no eclampsia nor hypertension during operation, her babies were intubated and were cared in pediatric ward. Though she had improvements of liver dysfunction and thrombocytopenia after operation, it took 2 days to extubated, because she had frequent attacks of bronchial asthma. We conclude that we should perform cesarean section for a patient with HELLP syndrome as soon as possible.

[A case of abortive malignant hyperthermia during funnel chest surgery]

We experienced a case of abortive malignant hyperthermia during funnel chest surgery. Although a 5-year-old boy had muscle rigidity after the intravenous injection of succinylcholine chloride, the tracheal intubation was easy. The boy had high body temperature, metabolic acidosis, hyperkalemia and myoglobinuria during nitrous oxide-oxygen-sevoflurane anesthesia. We immediately came to the diagnosis of abortive malignant hyperthermia, gave intravenous injection of dantrolene sodium and started body surface cooling. Postoperative course was uneventful. It is necessary to pay a particular attention to possible malignant hyperthermia in patients with funnel chest surgery.

[Severity of myasthenia gravis is related to the degree of neuromuscular blocking effect by isoflurane]

We studied neuromuscular blocking effects of isoflurane using a neuromuscular transmission monitor in three myasthenia gravis patients. Severity of myasthenia gravis was different among three patients. T1 decreased by 12% in a mild case (I type), by 18% in a moderate case (IIa type) and by 42% in severe case (III type) during isoflurane anesthesia. Also, TOF ratio decreased by 12% in a mild case, by 22% in a moderate case, and 48% in a severe case during isoflurane anesthesia. We conclude that in patients with more severe myasthenia gravis, neuromuscular blocking effect of isoflurane is more potentiated.

[Anesthetic management for cesarean section and clipping of aneurysm in a pregnant woman with ruptured cerebral aneurysm]

We report an anesthetic management for Cesarean section and clipping of aneurysm in a pregnant woman with a subarachnoidal hemorrhage secondary to a ruptured cerebral aneurysm. Anesthesia was induced with thiopental, vecuronium and sevoflurane, and maintained with sevoflurane (0.5-1%) before the delivery. Apgar score at 1 min was 1, but after 30 min her activity became almost normal. After the delivery, anesthesia was maintained with fentanyl for clipping surgery, because sevoflurane may inhibit uterine contraction and increase bleeding from the uterus after the delivery. We also infused prostaglandin E1 continuously at a rate of 50-70 ng.kg-1.min-1 to control arterial blood pressure and to maintain good contraction of the uterus during clipping surgery. We conclude that prostaglandin E1 is useful as a vasodilator after delivery because prostaglandin E1 contracts the uterus.

Pulmonary hypertensive response to rabbit blood components in goats: role of thromboxane

Transfusion of small quantities of heterologous blood may cause severe pulmonary hypertensive response in certain species. To determine the responsible component in the donor blood and the main mediator, we studied the responses of goats to small quantities of rabbit blood components and observed the effects of several pharmacologic agents on these responses. In anesthetized goats, a bolus injection of 0.004 ml/kg rabbit blood caused the pulmonary arterial pressure to increase from 25.3 +/- 2.8 to 57.1 +/- 11.6 cm H2O within 45 to 90 s, and the aortic thromboxane concentration rose from 44 +/- 38 to 238 +/- 104 pg/ml. Pulmonary vascular resistance increased more than 4-fold, whereas systemic vascular resistance increased moderately (50%). The erythrocyte stroma, mainly cell membranes, caused similar responses; other blood components were all ineffective. By blocking the production of thromboxane, indomethacin and U63557A (thromboxane synthetase inhibitor) abolished nearly all of the hemodynamic responses to rabbit blood. Isoproterenol also largely attenuated the responses to rabbit blood by blocking thromboxane production without interfering with the responses to the thromboxane mimic U46619. Nitrendipine (calcium-channel blocker) equally attenuated rabbit blood and U46619-induced hemodynamic responses but did not block thromboxane production. Chlorpheniramine (H1-receptor antagonist) partially blocked the hemodynamic responses to rabbit blood without affecting thromboxane production or U46619-induced responses. We conclude that the erythrocyte membrane is the responsible component in the donor blood and thromboxane is the predominant mediator. The main action of isoproterenol is to reduce thromboxane production and histamine participates by possible interaction with cyclooxygenase products.

[Pulmonary reaction after protamine reversal of heparin in goats and rabbits]

Protamine reversal of heparin is often associated with severe hemodynamic side-effects, including pulmonary hypertension in cardiovascular surgery. However, the precise mechanism of this transient pulmonary hypertension is not clear. Recently, it was reported that pulmonary intravascular macrophages (PIM) react avidly with and phagocytize various foreign particles (liposome, latex, red cells). Sheep, goat and pig have a large population of PIM, but rabbit, rat and human have few. To investigate whether the pulmonary reaction after protamine reversal is related to PIM, we compared the pulmonary reaction after protamine reversal between goats and rabbits. We also studied it in patients for cardiac surgery. Protamine sulphate (2 mg.kg-1) was injected in 2.5 min into femoral artery at five min after heparin sodium (200 IU.kg-1) injection in goats and rabbits. Mean pulmonary arterial and peak airway pressures increased significantly after protamine reversal in goat. On the other hand, in rabbit and human, mean pulmonary arterial and peak airway pressures showed no significant changes. Goat was far more sensitive to protamine reversal than rabbit and human. We conclude that PIM may be the main cause of the pulmonary reaction after protamine reversal.

[Angiotensin converting enzyme index increases after open cardiac surgery]

To investigate whether pulmonary endothelial cells are damaged after open cardiac, open chest, or head-neck surgery, we measured angiotensin converting enzyme (ACE) and calculated ACE index (ACE.cardiac output-1) to exclude the influence of pulmonary perfusion volume in 38 patients. There were no significant differences among three groups in serum ACE (9.93 +/- 2.46 IU.l-1 after open cardiac surgery, 8.50 +/- 2.75 IU.l-1 after open chest surgery, 10.71 +/- 2.23 IU.l-1 after head-neck surgery). ACE index after open cardiac surgery was significantly higher than those after open chest and head-neck surgery (2.43 +/- 0.85, 1.67 +/- 0.69, 1.64 +/- 0.50 respectively). These results suggest that ACE index detects pulmonary endothelial cell damage caused by reperfusion after cardiopulmonary bypass. We conclude that ACE index is more useful than ACE as an early clinical marker of pulmonary endothelial cell damage.

[A case of pneumomediastinum caused by closed tracheal injury during the game of Kendo (Japanese fencing)]

A patient was injured accidentally on his neck during the game of Kendo (Japanese fencing). After his neck injury, he continued to play Kendo because there was no symptom at that time. Starting 10 minutes after the injury, swelling as well as pain on the neck and dyspnea developed gradually. After the admission to the emergency room, computed tomography revealed pneumomediastinum. Nasal endotracheal intubation was performed gently under fiberscopy. Dyspnea and pneumomediastinum improved gradually during the 6 days after the admission. A patient who has received a closed injury on his neck without immediate symptoms or signs must be observed closely because the absence of symptoms or signs does not guarantee the absence of the injury of the trachea.

[Attenuation of cardiovascular response to laryngoscopy and tracheal intubation with bolus injection of diltiazem]

Effect of diltiazem on cardiovascular response to laryngoscopy and tracheal intubation was studied in 20 patients without hypertension and 10 patients with hypertension to be operated on under general anesthesia. The patients were divided into three groups: the first group without hypertension (group C, n = 10) received saline as control, the second group without hypertension (group N, n = 10) received bolus injection of diltiazem, and the third group with hypertension (group H, n = 10) received bolus injection of diltiazem. Diltiazem was administered 2 min before intubation at a dose of 0.2 mg.kg-1 as a bolus injection. Changes of mean blood pressure, rate pressure product, pressure rate quotient in group H and N decreased significantly compared with group C. Changes of heart rate were comparable among the three groups. Complications were not remarkable except one case in which systolic pressure decreased to 80 mmHg. The results suggest that bolus injection of diltiazem at a dose of 0.2 mg.kg-1 attenuates cardiovascular response to laryngoscopy and tracheal intubation without serious complications.

[Activation of complement and serial changes of anaphylatoxin (C3a, C5a) in patients for open-heart surgery using a membrane oxygenator]

Activation of complement and serum changes in anaphylatoxin (C3a and C5a) were studied in 8 patients who underwent open-heart surgery using a membrane oxygenator. C1 esterase inhibitor (C1-EI), C3, C5, CH50, C3a and C5a were measured serially at 7 points. C1-EI, C3, and C5 were measured by single radial immunodiffusion, CH50 by Mayer's method, and C3a and C5a by radioimmunoassay. Levels of C1-EI, C3 and C5 decreased significantly from 10 min after initiation to 120 min after the end of CPB compared with base line values. Degree of activation of complement increased in proportion to duration of CPB. Significant decreases of C3 and C5 continued until first postoperative day. Level of C3a increased significantly 10 min after initiation of CPB, and gradually increased till immediately after the end of CPB, when the level was maximum (4625 +/- 560 ng.ml-1) among 7 points. Level of C3a decreased gradually till 120 min after end of CPB. C5a was not detected during whole course. No patient showed respiratory distress of pulmonary edema. In conclusion, membrane oxygenator activated classical pathway of complement at 10 min after initiation of CPB. C3a increased significantly from 10 min after initiation of CPB to 120 min after end of CPB, but C5a was not detected at all during the whole course. The significant activation of complement continued till first postoperative day.

[Prostaglandin E1 infusion fails to inhibit the increase of serum granulocyte elastase and myeloperoxidase and the decrease of plasma angiotensin converting enzyme in patients undergoing open-heart surgery]

We studied whether prostaglandin E1 (PGE1) could inhibit the increase of serum granulocyte elastase (GEL) and myeloperoxidase (MPO), and the decrease of plasma angiotensin converting enzyme (ACE) induced by oxygenator in 19 patients undergoing open-heart surgery. The patients were randomly allocated into 2 groups: one group (PGE1 group, n = 9) received a continuous infusion of PGE1 at a rate of 30 ng.kg-1.min-1 during cardiopulmonary bypass (CPB), and the other group (control group, n = 10) received saline infusion. GEL, MPO and ACE were measured serially at 8 points: before induction of anesthesia (as baseline), immediately before initiation of CPB, 10 min after initiation, 60 min after initiation, immediately after the end of CPB, 60 min after CPB, 120 min after CPB, and on the first postoperative day. Serum levels of GEL and MPO during 120 min after the end of CPB in both groups increased significantly compared with the baseline values. There was no significant difference between the two groups. Plasma levels of ACE in both groups decreased significantly immediately after the end of CPB compared with values taken 10 min after the initiation of CPB. There was no significant difference between the groups. We conclude that the infusion of PGE1 30 ng.kg-1.min-1 failed to inhibit the increase of GEL as well as MPO, and the decrease of ACE.

Pulmonary hemodynamic reaction to foreign blood in goats and rabbits

We have found that the goat is extraordinarily sensitive to very small quantities of rabbit or rat blood. As little as 0.004 ml/kg induces transient pulmonary hypertension [maximal rise in pulmonary arterial pressure 32 +/- 10 (SD) cmH2O] in goats. We hypothesized that this reaction may be related to the presence of the resident population of intravascular macrophages that reside in the pulmonary capillaries of goats. If that is so, then rabbits or rats, which have few or no intravascular macrophages, should not be reactive to foreign blood. We compared pulmonary hemodynamics and changes in blood thromboxane B2 concentrations among goats, rabbits, and rats in response to graded doses of foreign blood. The pulmonary reaction to foreign blood was much greater in goats than in rabbits or rats, even though we injected up to 10- or 60-fold larger amounts into the latter species. In goats the pulmonary vascular pressure response to rabbit blood was dose dependent in goats and correlated well with changes in systemic arterial thromboxane B2 concentrations [change in pulmonary arterial pressure = 0.07 (thromboxane B2) + 8.3, r = 0.79]. We also tested the prostaglandin H2 endoperoxide analogue (U-46619) and found that the goats are somewhat more reactive than rabbits. We conclude that the pulmonary hemodynamic reaction to foreign blood is consistent with the concept that the foreign erythrocytes are reacting with the pulmonary intravascular macrophages in goats. The lower reactivity of the rabbit pulmonary circulation to thromboxane may also have a role.

[Effects of ulinastatin on granulocyte elastase and fibronectin in patients undergoing cardiopulmonary bypass]

We investigated the effects of ulinastatin on the increase of granulocyte elastase (GEL) and the decrease of fibronectin (FN) after cardiopulmonary bypass (CPB) in 30 patients undergoing cardiopulmonary bypass. Ulinastatin 300,000 units were given immediately after the induction of anesthesia (U1) or during CPB (U2). GEL increased by 20 times after CPB. GEL was lower in U2 than those in other groups. FN increased by 7-13% after CPB in U1 but decreased in other groups. FN decreased by 21-13% on the first postoperative day in three groups. There was a close relationship between CPB time and increase of GEL in the control group (no ulinastatin given) (y = 18.5 x -833, r = 0.751), between CPB time and increase of FN in U1 (y = 1.4 x -163.4, r = 0.683) or increases of GEL and FN in the control group (y = 0.068 x -202.6, r = 0.812). From these results, we recommend that ulinastatin should be given after the induction of anesthesia and during CPB, to keep a favorable host defense function after CPB.

[Effects of local anesthetics upon human natural killer cytotoxicity in vitro]

Effects of 3 local anesthetics, bupivacaine, mepivacaine and lidocaine, upon natural killer cytotoxicity were studied in vitro. Mononuclear cell layer was recovered by Ficoll-Paque sedimentation from heparinized venous blood obtained prior to the induction of anesthesia. The mononuclear cells were divided into three groups: control group was incubated in medium only: low concentration group incubated in medium with 2.0 micrograms.ml-1 of mepivacaine (n = 20) or lidocaine (n = 20), or 0.5 micrograms.ml-1 of bupivacaine (n = 21); high concentration group in medium with 20 micrograms.ml-1 of mepivacaine or lidocaine, or 5 micrograms.ml-1 of bupivacaine. These three groups were incubated simultaneously in humidified atmosphere with 5% CO2 in incubator for 2 hours. NK cell cytotoxicity was determined in a chromium release assay against K 562 cell as a target cell. An effector to target cell ratio of 40:1 was used. Comparison among 3 local anesthetics showed no significant difference at high concentration, but a significant difference at low concentration. This was due to the differences between bupivacaine and lidocaine. Neither bupivacaine nor mepivacaine inhibited % NK cytotoxicity at both low and high concentrations compared with control. Lidocaine significantly inhibited % NK cytotoxicity at low concentration, but did not inhibit at high concentration compared with control. We concluded that neither bupivacaine nor mepivacaine inhibited % NK cytotoxicity at concentration of clinical dose compared with control in vitro, but lidocaine inhibited % NK cytotoxicity at a concentration of 2.0 micrograms.ml-1 compared with control.

[Effect of isoflurane on muscle relaxation in a patient with myotonic dystrophy]

We did anesthetic management by isoflurane for total thyroidectomy under the neuromuscular transmission monitoring in a patient with myotonic dystrophy. In three patients without neuromuscular disorders, T1 was 85% of control and fade was not observed, while in this case T1 was 40% of the control and TOFR was decreased to 50%. We conclude that isoflurane has a good muscle relaxation effect in this disease and, we could manage without administering any muscle relaxants.

[General anesthesia and surgery inhibited natural killer cell cytotoxicity in patients with cancer or benign disease undergoing upper abdominal surgery]

In this study, effect of enflurane anesthesia combined with epidural analgesia on natural killer cell cytotoxicity (NKCC) was investigated in 20 patients. Patients were divided into two groups: the first group with adenocarcinoma of stomach (Group 1); the second with cholecystolithiasis (Group 2). Four samples were taken; 1) on arrival at operating room; 2) during anesthesia and 1 hour after skin incision; 3) on 1st postoperative day; and 4) on 4th or 5th postoperative day. NKCC was determined with a chromium release assay against K 562 cell. NKCC was already significantly higher before induction in Group 1 compared with Group 2 and normal value. In Group 1, NKCC decreased significantly compared with baseline during operation, but in group 2 NKCC was unchanged during operation. NKCC in group 2 was inhibited significantly less than Group 1 during 5 postoperative days, while NKCC was significantly inhibited postoperatively in both groups compared with the baseline. We conclude that enflurane anesthesia combined with epidural analgesia and surgery did not decrease NKCC below normal value during operation, but it was significantly inhibited during 5 postoperative days in both groups. There were differences in responses to stress of anesthesia and surgery between patients with and without cancer.

Effect of controlled mechanical ventilation without positive end-expiratory pressure on right ventricular function after coronary artery bypass graft surgery

To evaluate the changes in right ventricular function during controlled mechanical ventilation (CMV) without positive end-expiratory pressure (PEEP) and during spontaneous breathing, we compared right ventricular ejection fraction (RVEF), right ventricular end-diastolic volume index (RVEDVI), and right ventricular end-systolic volume index (RVEDVI) using a thermodilution technique after coronary artery bypass graft surgery. Patients were divided into two groups on the basis of changes in RVEDVI from CMV to spontaneous breathing: group U (n = 6) consisted of patients whose RVEDVI increased during spontaneous breathing compared with mechanical ventilation, group D (n = 3) consisted of patients whose RVEDVI decreased during spontaneous breathing compared with mechanical ventilation. PVRI values during CMV in group D were significantly larger than those in group U. Patients in group U showed no increase in RVEDVI, or decrease in RVEF during CMV without PEEP. However, the remaining 3 patients in group D showed an increase in RVEDVI and a decrease in RVEF during CMV. Mean PAP, RAP, RV systolic pressure, RV end-diastolic pressure, PWP, HR, and mean arterial pressure in both groups were comparable, and showed no significant difference at each of the measured points by 24 hrs postoperatively. Then, RVEF, RVEDVI and RVESVI measured by thermodilution technique is useful in evaluating ventricular function at bedside in ICU.

[Statistical analysis of tracheobronchial foreign bodies]

Incidence of foreign body aspiration in tracheobronchial tree is rare, however the foreign body aspiration can lead to severe illness and even death if not diagnosed and treated promptly. We retrospectively analyzed forty five patients who underwent ventilation bronchoscope under general anesthesia for suspected aspirated foreign bodies in our hospital. In thirty eight patients, foreign body was confirmed in tracheobronchial tree, while in seven patients foreign body was not confirmed with bronchoscope. The thirty eight patients ranged in age from 10 months to 73 years; the peak incidence of foreign body aspiration occurred in children under 3 years of age. Twenty five of thirty eight patients were male. Food or food derivatives were the causative agents in 68% of the patients, with 65% due to a portion of peanut. The foreign body was located in the right and left bronchus with almost equal frequency. The main symptoms were coughing (72%), wheezing (53%), and dyspnea (25%). The radiographic abnormality was seen in eighteen of thirty eight patients. A radio-opaque material was seen in 18%. Children at age 6 years of younger (90%) had been witnessed to choke on identifiable foreign body, but only 40% were diagnosed within 24 hours. Twelve of these children were treated unnecessarily for asthma, pneumonia, or so on. We conclude that it is most important to take history carefully considering the possibility of foreign body aspiration in the patients with coughing, wheezing, or dyspnea.

[The evaluation of incremental positive end-expiratory pressure on right ventricular hemodynamics as determined by the thermodilution technique]

Effects of incremental positive end-expiratory pressure (PEEP) on right ventricular (RV) hemodynamics were studied in 10 patients undergoing coronary artery bypass grafting, abdominal aneurysmectomy and partial hepatectomy, using Swan-Ganz catheter mounted with the rapid response thermistor. PEEP was increased from 0 (baseline) to 15 cmH2O with increment of 5 cmH2O, and right ventricular ejection fraction (RVEF), RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), and cardiac output (CO) were computed with a thermodilution technique at each PEEP. At 15 cmH2O PEEP, RVEF, RVEDVI and RVESVI were comparable with the baseline, while right arterial pressure, RV peak systolic pressure and mean pulmonary arterial pressure increased significantly compared with the baseline. Increased afterload of RN caused by PEEP did not affect RV contractility. Decreased cardiac and stroke volume indices were attributed to the decrease of preload caused by the increase of intrathoracic pressure. We conclude that PEEP at 5 to 15 cmH2O does not influence right ventricular hemodynamics, and RVEDV is a reliable index to monitor RV hemodynamics instead of right arterial pressure to determine optimal PEEP.