Recently acute pulmonary thromboembolism (APE) has been recognized as one of the common emergent cardiopulmonary disorders. However it is afraid that so many non-overt APE may be overlooked clinically. It is neccessary for the diagnosis to recognize that APE is not rare disease in Japan and to know the non-specific clinical features. Usually the definitive diagnosis for APE is established by the lung scan with perfusion defect and/or pulmonary arteriography with cut-off sign or filling defect. In the case of massive APE with shock, bedside echocardiography is sometimes available for prompt diagnosis and treatment.
The first choice for management of APE is heparin. The indication for thrombolytic therapy with tissue plasminogen activator, surgical embolectomy, catheter embolectomy and the implantation of inferior cavalvein filter is controversial. Since the reccurent attack often leads to fatal outcome, the early evaluation and management for deep vein thrombosis of lower extremities as the source of APE is recommended.

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Errors in measurement by pulse oximeters were thought to be caused by electric warming blankets in patients with peripheral hypoperfusion. This hypothesis was tested experimentally on healthy volunteers. Large fluctuations (0-99%) of oxygen saturation (SpO₂) were observed with peripheral hypoperfusion experimentally induced by compression of the upper arm. An oscilloscope displayed cyclic noises of 50Hz from light absorbance signals when the blanket was on. The mean noise voltage decreased by 99% when the blanket was shielded with a conductive cover, and decreased by 5-63% when the probe of the pulse oximeter was shielded.
No fluctuations of SpO₂ were recorded after changing the frequency of light absorbance measurements from intervals of 3.3msec to 4.4msec. These results demonstrated that pulse-oximetric errors induced by an electric blanket can be avoided by changing the frequency of light absorbance measurements.

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Respiratory complications are often experienced in the postoperative course of radical operation for thoracic esophageal cancer. Eighty-one patients who underwent radical operations for thoracic esophageal cancer between 1988 and 1993 were divided into two groups. One group of patients (51 cases) were intubated until complete restoration of the cough reflex was confirmed (about one week). Another group (30 cases) were extubated on the second or third postoperative day with or without cough reflex. The incidence of respiratory complications was investigated in the two groups. The incidence of pneumonia was 43% in the former and 17% in the latter group. The incidence of upper airway troubles (e. g. vocal cord dysfunction and laryngeal edema) was 76% in the former group and 50% in the latter group.
The differences between the two groups were significant. Long-term intubation was thought to cause upper airway dysfunction and misswallowing, which might lead to postoperative pneumonia. These results suggest that extubation of the tracheal tube should occur during the early postoperative period to preserve upper airway and laryngopharyngeal function. Insertion of a minitracheotomy tube enabled effective pulmonary physical therapy to proceed in spite of an impaired cough reflex.

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Bronchoalveolar lavage fluid (BALF) from patients with adult respiratory distress syndrome (ARDS) were assayed for phospholipase A₂ (PLA₂) activity. Enhanced PLA₂ activity was directly correlated with the severity of the disease. Heparin-Sepharose chromatography showed PLA₂ activity was divided into two distinct peaks.
The heparin-binding fractions appeared to be similar to group II PLA₂ activity. The heparin-non-binding fractions were further purified.
A different type of highly active PLA₂ with high molecular weight and calcium dependency was found. But in a neutral and optimum pH (optinal pH for high molcular mass is 9.0) it did not show immunoprecipitation against antipancreatic PLA₂ antiserum or anti-pig spleen cytosolic 100kDa PLA₂ antiserum. This new type of PLA₂ was detected in the bronchoalveolar lavage fluid of patients with ARDS.

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The effect of amrinone on gas exchange and oxygen metabolism were evaluated in eight patients after cardiovascular surgery for cardiopulmonary bypass.
Amrinone was adminisered without bolus infusion (infusion rate: 10μg·kg^-1·min^-1). Data were obtained 30 minutes and 90 minutes following amrinone administration and were compared to the control data. Values are described as mean±SD.
Non-nutrient blood flow (NNBF) and conventional parameters for oxygen metabolism were used to evaluate regional blood flow. NNBF was calculated with Farrell's formula.
Both the respiratory index (from 1.4±1.1 to 2.1±1.2 (30min), 2.4±1.5L·min^-1·m^-2 (90min)) and pulmonary shunt (from 10.1±to 11.6±6% (30m), 12.1±5% (90min)) significantly (p<0.05) increased. Mean pulmonaly arterial pressure (from 23±8 to 18±7mmHg (90min)) and the pulmonaly vascular resistance index (from 317±87 to 221±61 dyne sec·cm^-5·m^-2 (90min)) significantly decreased (p<0.05).
The cardiac index increased significantly (p<0.05) (from 2.5±0.6 to 3.0±0.9L·min^-1·m^-2 (90min)). Oxygen consumption showed a significant (p<0.05) increase (from 185±34 to 220±88ml/min. (90min)) but oxygen saturation of mixed venous blood was not altered (from 68±5 to 65±6% (90min)). The control values of NNBF indicated insufficient regional blood flow. Amrinone significantly increased NNBF (from-34±25 to -8±33% (90min)).
These results suggest that amrinone increases cardiac output and regional blood flow, thus improving oxygen metabolism. They also suggest, however, that amrinone increases pulmonary shunt which leads to decreased gas exchange in patients after cardiovascular surgery.

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Patients who underwent subtotal esophagectomy were extubated on the first postoperative day in order to avoid postoperative pulmonary complications and discomfort. Extubation was carried out if the patient satisfied the following criteria: no ischemic change in the mucosa, PaO₂ greater than 100mmHg, and PaCO₂ less than 45mmHg under 2cm H₂ O CPAP or a T-piece with an FiO₂ of 40%. Fiberoptic bronchoscopy (FBS) was then performed under topical anesthesia to aspirate sputum in the bronchial trees. We retrospectively studied the duration of tracheal intubation and the number of days, on which FBS was required after extubation in 41 patients. They were analyzed with regard to two preoperative measures; one-second forced expiratory volume (FEV 1) greater or less than 2.0L, and smoking history. The duration of tracheal intubation except for two tracheostomy cases was 1.8±1.7 days (mean±SD). Twenty-seven patients (66% of all patients) were extubated on the first postoperative day. The duration of intubation was not affected significantly by the risk factors. However, four patients in whom the duration of intubation was longer than 3 days, and two who required tracheostomy for long-term pulmonary care, were all smokers. FBS was required for 3.7±2.0 days after surgery. The duration of FBS was not affected by the value of FEV 1. However, smokers required FBS for a longer period (4.1±2.2 days) than non-smokers (2.9±1.2 days, p<0.05). Twelve patients who required FBS for more than 5 days were all smokers (p<0.02). We conclude that it is not risky to extubate on the first postoperative day if FBS is performed to clean airway secretions. However patients with a smoking history require prolonged pulmonary care after subtotal esophagectomy.

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Despite its physiological importance, physiologically active ionized magnesium (iMg²⁺) has not been measured in critically ill patients for lack of methodology. A new magnesium ion selective electrode was used to measure whole blood iMg²⁺ and ionized calcium (iCa²⁺) in 29 critically ill patients and 36 healthy volunteers.
Levels of iMg²⁺ were significantly lower on admission (0.47±0.08mmol·1^-1, mean±SD) and at 6±1 ICU days (0.48±0.12mmol·1^-1) in the patient group than in the control group (0.53±0.04mmol·1^-1). There was no correlation between iMg²⁺ and total magnesium in the critically ill patients. Levels of ionized Ca²⁺ showed the same trends as iMg²⁺, however, the ratio of iMg²⁺/iCa²⁺ at the two points in the patient group were not different from that of the control group. The significant correlation between iMg²⁺ and iCa²⁺ found in the control group was not seen on admission in the patient group, but was re-established at 6±1 ICU days.
Ionized magnesium (iMg²⁺) decreases in critically ill patients making it an important measure to monitor.

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The sedative effects and pharmacokinetics of midazolam, continuously administered for one week, were examined in 5 patients with burns under mechanical ventilation. Initially 0.2mg·kg^-1 of midazolam was administered intravenously then additional midazolam was injected at a rate of 0.2±0.05mg·kg^-1·hr^-1 over one week. No significant changes were observed in blood pressure or heart rate in any patients during the infusion period. Plasma concentrations of midazolam which were analyzed using high performance gas chromatography remained stable with a mean value of 1179.5±244ng·ml^-1 (mean±SD). Mean plasma concentrations of midazolam decreased rapidly to about 70% of the initial level one hour after the infusion was terminated, and to about 50% four hours after.
In conclusion, continuous infusion of midazolam in doses of 0.2±0.05mg·kg^-1 was very effective for the sedation of patients with burns under mechanical ventilation, causing minimal side effects on the cardiovascular system and resulting in rapid recovery of consciousness.

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Plasma exchange (PE) was performed three times within seven days from the onset of symptoms (total exchanged plasma volume; 180ml·kg^-1) in a two-year old female child with severe Guillain-Barré syndrome who required mechanical ventilation.
This was followed by Immunoglobulin therapy (0.4g·kg^-1·day^-1) for 5 days. The patieat was weaned from mechanical ventilation on the 34th day in the ICU.
Centrifugal PE with a larger circuit volume was complicated by hemodilution, while ultrafiltration PE was complicated by intra-circuit hemolysis. Although the hemodynamics remained stable and no obvious electrolyte abnormalities were observed in this patient, changes in blood constitution should be carefully monitored during PE.
Combined immunoglobulin therapy should be considered in cases such as this with aggravated neurological symptoms or decreased plasma constituents such as lipid and globulin after early stage serial PE.

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