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1.
Psychosom Med ; 62(3): 365-73, 2000.
Article in English | MEDLINE | ID: mdl-10845350

ABSTRACT

OBJECTIVE: Elective surgery represents a considerable source of stress for the patient. Many attempts have been made to prepare patients before surgery with the aim of reducing stress and improving outcome. This study used a novel approach to fulfill this aim by showing a videotape of a patient undergoing total hip replacement surgery, covering the time period from hospital admission to discharge, that strictly keeps to the patient's perspective. METHODS: Before elective total hip replacement surgery, 100 patients were randomly assigned to a control group or a preparation group; the latter group was shown the videotape on the evening before surgery. Anxiety and pain were evaluated daily for 5 days, beginning with the preoperative day, by means of the State-Trait Anxiety Inventory and a visual analog scale. Intraoperative heart rate and blood pressure, as well as postoperative intake of analgesics and sedatives, were recorded. Urinary levels of cortisol, epinephrine, and norepinephrine were determined in 12-hour samples collected at night for 5 nights, beginning with the preoperative night. RESULTS: Compared with the control group, the preparation group showed significantly less anxiety on the morning before surgery and the mornings of the first 2 postoperative days, and significantly fewer of them had an intraoperative systolic blood pressure increase of more than 15%. The pain ratings did not differ significantly between the two groups, but the prepared patients needed less analgesic medication after surgery. Prepared patients had significantly lower cortisol excretion during the preoperative night and the first 2 postoperative nights. Excretion of catecholamines did not differ significantly between groups. CONCLUSIONS: We conclude that use of the videotape decreased anxiety and stress, measured in terms of urinary cortisol excretion and intraoperative systolic blood pressure increase, in patients undergoing hip replacement surgery and prepared them to cope better with postoperative pain.


Subject(s)
Arthroplasty, Replacement, Hip/methods , Health Education , Preoperative Care , Stress, Psychological/prevention & control , Videotape Recording , Adaptation, Psychological , Aged , Analgesics/therapeutic use , Anxiety/diagnosis , Anxiety/drug therapy , Anxiety/etiology , Catecholamines/urine , Female , Humans , Hydrocortisone/urine , Hypertension/etiology , Hypertension/prevention & control , Hypnotics and Sedatives/therapeutic use , Middle Aged , Pain, Postoperative/psychology , Stress, Psychological/psychology , Surveys and Questionnaires
2.
J Hosp Infect ; 39(3): 195-206, 1998 Jul.
Article in English | MEDLINE | ID: mdl-9699139

ABSTRACT

The development of bacterial resistance during selective decontamination of the digestive tract (SDD) is controversial. We studied effects on bacterial resistance one year before and during a randomized, placebo-controlled trial of SDD in a surgical intensive care unit. We randomized patients within two different topical regimens (PTA, PCA) or placebo, administered four-times daily to both the oropharynx and gastrointestinal tract. All patients received intravenous ciprofloxacin (200 mg b.d.) for four days. Both SDD regimens successfully reduced aerobic Gram-negative intestinal colonization. There was no increase in resistance of Enterobacteriaceae or Pseudomonas aeruginosa. Acinetobacter calcoaceticus developed multi-resistance over one year, but differences between groups were not significant. We detected a shift towards Gram-positive organisms. Oxacillin-resistant Staphylococcus aureus increased in concert with ciprofloxacin resistance, from 17 to 80.7%, and frequencies of resistance were significantly higher in SDD patients (P < 0.001). Resistance of coagulase-negative staphylococci (CNS) to oxacillin increased initially (25 to 66.9%), but values returned to baseline in controls. Ciprofloxacin resistance in CNS remained higher (P < 0.001) in SDD-treated patients (52.5 vs. 23.3%). The incidence of late respiratory tract infections was unaltered by the prophylactic regimen (SDD 35.2%; Placebo 41.2%; n.s.). We cannot recommend SDD as a prophylactic tool in critically ill patients.


Subject(s)
Cross Infection/microbiology , Decontamination/methods , Intestines/microbiology , Adult , Austria , Cross Infection/drug therapy , Cross Infection/etiology , Double-Blind Method , Drug Resistance, Microbial , Ecology , Female , Hospitals, University , Humans , Male , Middle Aged , Multiple Trauma/complications , Multiple Trauma/microbiology , Prospective Studies , Time Factors
3.
J Trauma ; 42(4): 687-94, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9137259

ABSTRACT

BACKGROUND: Reduction of potential pathogens by selective intestinal decontamination has been proposed to improve intensive care. Despite large scientific interest in this method, little is known about its benefit in homogeneous trauma populations. METHODS: In a prospective, controlled study, we enrolled non-infected trauma patients (age over 18 years, mechanical ventilation > or = 48 hours, intensive care for more than 3 days) who primarily were admitted to our university medical center. We randomized patients to be treated with two different topical regimens (polymyxin, tobramycin, and amphotericin (PTA) or polymyxin, ciprofloxin, amphotericin (PCA)) or the carrier only (placebo), administered four times daily both to the oropharynx and to the gastrointestinal tract. All patients received intravenous ciprofloxacin (200 mg, bd) for 4 days. FINDINGS: Of 357 enrolled patients, 310 (age 38.0 +/- 16.5 years, Injury Severity Score 35.2 +/- 12.7) met all inclusion criteria. Selective decontamination successfully reduced intestinal bacterial colonization. However, we did not identify significant differences between groups regarding pneumonia (PTA 47.5%, PCA 39.0%, placebo 45.3%), sepsis (PTA 47.5%, PCA 37.8%, placebo 42.6%), multiple organ failure (PTA 56.3%; PCA 52.4%, placebo 58.1%), and death (PTA 11.3%, PCA 12.2%, placebo 10.8%). Total costs per patient were highest with the PTA regimen. CONCLUSIONS: We found no benefit of selective decontamination in trauma patients. Apparently, bacterial overgrowth in the intestinal tract is not the sole link between trauma, sepsis, and organ failure.


Subject(s)
Amphotericin B/therapeutic use , Anti-Bacterial Agents/therapeutic use , Anti-Infective Agents/therapeutic use , Ciprofloxacin/therapeutic use , Colistin/therapeutic use , Drug Therapy, Combination/therapeutic use , Multiple Trauma/complications , Pneumonia/prevention & control , Tobramycin/therapeutic use , Adult , Bacterial Translocation , Double-Blind Method , Female , Humans , Intestines/microbiology , Male , Pneumonia/etiology , Prospective Studies , Respiration, Artificial/adverse effects
6.
Anaesthesist ; 43(7): 454-62, 1994 Jul.
Article in German | MEDLINE | ID: mdl-8092455

ABSTRACT

As early as 1974, Brian advocated the prone position for ventilated patients. He suggested that this position might enhance ventilation of the dorsal parts of the lungs, thereby improving oxygenation. These considerations have been confirmed by several experimental and clinical studies. Better secretion removal, decreased intrapulmonary shunting, and an increased FRC are thought to be responsible for the observed improvement of oxygenation. However, the prone position never became very popular in the clinical treatment of the adult respiratory distress syndrome (ARDS). Routine performance of thoracic CT scans in ARDS patients demonstrated preferential distribution of pathological densities in the dependent lung areas. The prone position therefore could possibly benefit these patients, as shown by two recent studies. The aim of our study was to evaluate the influence of repeatedly turning the patient to the prone position on gas exchange and thoracic CT findings in multiple-trauma patients. METHODS. Seven ventilated intensive care patients with severe ARDS (Murray Score > 2.5, Quotient > 0.7, mean airway pressure > 18 cm H2O, thoracic CT scan showing dorsal atelectases) were included in the study. Patients were turned from the supine to the prone position at 12-h intervals using an air-cushion bed (Mediscus, Austria). Redistribution of dystelectatic or atelectatic dependent lung areas was verified by means of repeated thoracic CT scans (Figs. 1, 8). RESULTS. The patients were intermittently turned for 6.5 +/- 1.1 days. The course of gas exchange is shown in Figs. 2 and 3. Initially, improvement of the respiratory quotient could only be achieved during prone positioning, from the 2nd day in the supine position as well. Intrapulmonary shunting showed a similar trend (Figs. 4 and 5). No significant changes in cardiovascular parameters could be observed. Control thoracic CT scans showed uniform reduction of atelectases in dependent lung areas (Figs. 1 and 8). The inspiratory fraction of oxygen could be reduced significantly as of the 2nd day (Fig. 7). Constant levels of positive end-expiratory pressure and tidal volume were associated with decreasing mean and plateau airway pressures (Fig. 6). DISCUSSION. Repeatedly turning the patient to the prone position produced long-lasting improvement of arterial oxygenation, which persists up to the end of the weaning process. This is in good accordance with other studies, however, this is the first study to report an observation period of more than 6 days of repeatedly turning the patient. These positive effects on gas exchange can be attributed to sudden improvement of the ventilation-perfusion ratio within the lung areas that become dependent after turning to the prone position. Due to reduced hydrostatic pressure and relative hyperventilation, previously collapsed alveoli are recruited in the lung areas that become non-dependent after turning to the prone position.


Subject(s)
Prone Position , Respiratory Distress Syndrome/therapy , Adult , Humans , Middle Aged , Multiple Trauma/complications , Pulmonary Atelectasis/therapy , Pulmonary Gas Exchange/physiology , Respiration, Artificial , Respiratory Distress Syndrome/diagnostic imaging , Respiratory Distress Syndrome/physiopathology , Respiratory Function Tests , Tomography, X-Ray Computed
7.
Wien Klin Wochenschr ; 106(13): 407-11, 1994.
Article in German | MEDLINE | ID: mdl-8091764

ABSTRACT

In spontaneous breathing intrathoracic pressure alternates between positive and negative in a biphasic sequential pattern. By contrast, during mechanical ventilation (IPPV, CPPV) the intrathoracic pressure remains above atmospheric all the time. Due to these unphysiological conditions there are extensive causal and side effects on the lung parenchyma and other organs. Errors in the artificial ventilation technique can magnify these effects. In order to minimize these deleterious effects of positive pressure ventilation it is essential to keep the procedure as short and little invasive as possible. The following strategy enables this goal to be brought closer: 1) early commencement of ventilation; 2) optimal adjustment of artificial ventilation to the individual needs of the patient, 3) early weaning from assisted ventilation through augmented rather than controlled modes of ventilation: 4) kinetic therapy (systematic changing of the patient's position) with the back up of the requisite thoracic CT scan findings; 5) reduction of the invasiveness of the procedure in order to ensure early commencement of spontaneous respiration.


Subject(s)
Respiration, Artificial/methods , Humans , Lung Volume Measurements , Pneumothorax/etiology , Pneumothorax/prevention & control , Pulmonary Atelectasis/etiology , Pulmonary Atelectasis/prevention & control , Respiration, Artificial/adverse effects , Respiratory Distress Syndrome/etiology , Respiratory Distress Syndrome/prevention & control , Ventilation-Perfusion Ratio/physiology , Ventilator Weaning
8.
Eur J Anaesthesiol ; 11(1): 37-42, 1994 Jan.
Article in English | MEDLINE | ID: mdl-8143712

ABSTRACT

Biphasic Positive Airway Pressure (BIPAP) can be described as pressure controlled ventilation in a system allowing unrestricted spontaneous breathing at any moment of the ventilatory cycle. It can also be described as a Continuous Positive Airway Pressure (CPAP) system with a time-cycled change of the applied CPAP level. As with a pressure controlled, time-cycled mode, the duration of each phase (T(high), T(low)) as well as the corresponding pressure levels (P(high), P(low)) can be adjusted independently. Depending on the spontaneous breathing activity, BIPAP can be subdivided into: no spontaneous breathing: CMV-BIPAP; spontaneous breathing at the lower pressure level: IMV-BIPAP; spontaneous breathing at the upper pressure level: APRV-BIPAP; spontaneous breathing at both CPAP levels: genuine BIPAP. Since it enables progressive transition from controlled to all levels of augmented mechanical ventilation, BIPAP appears to be a suitable mode for the entire period of mechanical ventilation of the patient. There are difficulties neither in choosing the correct moment for switching nor the further respiratory management of the ventilated patient under BIPAP. The necessary adaptation (ventilation, oxygenation) can be individualized on the basis of blood gas analyses. An increase or reduction of the invasivity of ventilation can be attained without any problems with BIPAP. Furthermore, spontaneous breathing of the patient does not necessitate any switching of the mode of ventilation. The transition from controlled to augmented ventilation is smooth. BIPAP enables the therapist to let the patient breathe freely even under the most invasive ventilation conditions.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Respiration, Artificial/methods , Humans , Respiration, Artificial/instrumentation
9.
Anesthesiology ; 77(4): 675-80, 1992 Oct.
Article in English | MEDLINE | ID: mdl-1416164

ABSTRACT

Cholecystectomy performed via laparotomy is associated with reduction of lung volumes including functional residual capacity that may lead to postoperative hypoxia and atelectasis. Laparoscopic cholecystectomy is associated with faster recovery compared to open laparotomy and cholecystectomy. To determine whether laparoscopic cholecystectomy was associated with less pulmonary dysfunction, 20 patients (ASA Physical Status I) undergoing elective cholecystectomy were randomly assigned to surgical teams performing either laparoscopy or open laparotomy for cholecystectomy. Patients in whom one or the other surgical technique had to be performed for medical or psychologic indications were excluded from the study. A standardized anesthetic technique and postoperative analgesic regimen were used. Forced vital capacity and forced expiratory volume in 1 s; functional residual capacity determined by a closed-circuit, constant volume helium dilution technique; and arterial O2 and CO2 tensions were measured preoperatively and at 6, 24, and 72 h postcholecystectomy. Forced vital capacity and forced expiratory volume in 1 s were significantly greater (P less than 0.05) in the laparoscopy compared to the laparotomy group at 6, 24, and 72 h postoperatively. Forced vital capacity relative to preoperative values was significantly (P less than 0.05) greater in patients with laparoscopy (24 h, 70 +/- 14%; 72 h, 91 +/- 6%) compared to open laparotomy (24 h, 57 +/- 23%; 72 h, 77 +/- 14%). Similarly, forced expiratory volumes in 1 s relative to preoperative values were significantly (P less than 0.05) greater in patients with laparoscopy (24 h, 85 +/- 13%; 72 h, 92 +/- 9%) compared to open laparotomy (24 h, 54 +/- 22%; 72 h, 77 +/- 11%).(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Cholecystectomy , Laparoscopy , Laparotomy , Postoperative Complications/physiopathology , Respiration Disorders/physiopathology , Adult , Female , Forced Expiratory Volume/physiology , Functional Residual Capacity/physiology , Humans , Male , Middle Aged , Postoperative Complications/epidemiology , Prospective Studies , Respiration Disorders/epidemiology , Vital Capacity/physiology
12.
Anaesthesist ; 39(10): 456-62, 1990 Oct.
Article in German | MEDLINE | ID: mdl-2278362

ABSTRACT

Anesthesiologists have always played a leading role in research into pain and its treatment. Their efforts, however, have been focused on acute or postoperative pain problems. It was the American anesthesiologist John J. Bonica who fought for an increased interest in chronic pain. The establishment of the first Multidisciplinary Pain Center at the University of Washington in Seattle, the foundation of the International Association for the Study of Pain (IASP) and Melzack and Wall's now 25 year old gate control theory were the driving forces behind rapid developments in research and treatment in the area of chronic pain. The realization that chronic pain was the most frequent cause of disability in the United States also gave an impetus for new efforts in treatment. The classic anesthesiological topics, such as operative anesthesia emergency medicine and intensive care, have been extended to include acute pain services and chronic pain treatment facilities. This reflects the understanding that anesthesiological knowledge and techniques can be valuable to patients in severe acute pain and those in lingering long-term chronic pain phases. Anesthesiologists are skilled in the use of opioid narcotics and in the administration of strong analgesics. Many severe pain problems can be solved by correct use of the analgesic regimen. Special ways of administering narcotic analgesics, such as epidural infusion or patient-controlled analgesia, have already alleviated the pain problems of many patients. Anesthesiological techniques are also crucial in diagnosis. Sequential differential blockade and simple nerve blocks can be helpful in the diagnosis and classification of the pain problems. Anesthesiological contributions to a chronic pain service are not restricted to medical interventions. Organizational skills are also needed for efficient running of multidisciplinary pain treatment facilities. Clinical practice in surgical anesthesia means that anesthesiologists are experienced in interdisciplinary work and familiar with the advantages and dangers of team work. Despite international acceptance of the multidisciplinary approach to chronic pain, there is still a lack of appropriate facilities in the German-speaking countries, and we consider it important that anesthesiologists commit themselves to increasing general awareness of what is needed.


Subject(s)
Ambulatory Care Facilities/organization & administration , Anesthesiology , Pain Management , Austria , Chronic Disease , Humans , United States
13.
Anaesthesist ; 39(10): 469-74, 1990 Oct.
Article in German | MEDLINE | ID: mdl-2278364

ABSTRACT

In this study the outcome of out-of-hospital cardiac arrest (CA) was analyzed during the first 3 years after installation of a mobile intensive care unit (MICU). The unit is staffed by an anesthesiologist as the emergency-care physician and specially trained health-care personnel. The success of cardiopulmonary resuscitation (CPR) was classified into three stages: (1) CPR with temporary cardiac output; (2) CPR primarily successful with spontaneous rhythm and a palpable pulse; (3) CPR, definitely successful resulting in the patient's discharge from the hospital without important neurological sequelae. All patients are grouped according to the disease underlying the CA. The performance of bystander CPR was recorded. The influence the factors sex, age, response time, cardiac rhythm, location of the collapse and period of investigation (1st year, 2nd year, 3rd year) had on the outcome was analyzed. RESULTS. Eighty-nine patients (32.96%) had a temporary cardiac output; 56 patients (20.74%) were primarily successfully resuscitated; and 12 patients (4.44%) survived without important neurological sequelae. Most of the diseases underlying the CA were in the internal disease group. Only 16 cases of bystander CPR performance were recorded. In the group with primarily successful CPR, significantly important factors arose with the increasing CPR success rate due to the period of investigation (1st year: 10.00%, 2nd year: 19.61%, 3rd year: 30.77%) and due to cardiac rhythm "ventricular fibrillation" (34.62%) and "asystole" (11.88%). Furthermore, significantly important factors were found for definite CPR success when comparing males (1.72%) and females (10.64%) and comparing the location of the collapse "in public places" (9.80%) and "at home" (2.00%). CONCLUSION. Our study shows that in spite of installing a MICU, the outcome of CPR is poor without supplementary measures. We consider that systematically teaching the public about basic life support measures and teaching medical students about emergency medicine will lead to a better CPR success rate in combination with continuing education of the MICU personnel.


Subject(s)
Ambulances , Resuscitation/statistics & numerical data , Age Factors , Austria , Female , Humans , Male , Prognosis , Sex Factors
14.
Anaesthesist ; 39(10): 530-4, 1990 Oct.
Article in German | MEDLINE | ID: mdl-2278373

ABSTRACT

Pulmonary failure is almost always present in the early or late phase of multiple organ failure (MOF). Acute lung failure (ALF) is a uniquely constant response to direct or indirect insults to the lung. Increased pulmonary microvascular permeability (PMVP) is associated with the onset of lung permeability edema, the hallmark of ALF. The sequence of PMVP and the development of ALF caused by direct insults are studied. METHODS. A series of 255 trauma patients admitted to our intensive care unit (ICU) from 1987 to 1988 were enrolled in this prospective study. ALF was defined as stage III of the Posttraumatic Pulmonary Insufficiency Score; sepsis syndrome, according to Montgomery; organ failure, as stage II of the MOF score, and MOF was recorded when at least two organs had failed. Thoracic injury and aspiration were expected as direct, sepsis and shock alone as indirect insults to the lung. A computerized large field of view gamma camera was used to measure PMVP simultaneously over both lungs by means of 113mIn-transferrin and 99mTc-erythrocytes. The pulmonary microvascular permeability index (PMVPI; %/h) was used to quantify PMVP in the dynamic scintigraphic measurement. RESULTS. Of the 255 trauma patients (ISS = 33.9 +/- 18.7), 21% (52) patients (ISS = 41 +/- 17.8) developed ALF. 50 (or 96%) of the ALF patients developed MOF in addition, and 27 (72%) of the patients with directly induced ALF developed sepsis syndrome later. Direct lung injury was present in 77% (37) of the patients with posttraumatic ALF. Thoracic injury was the main cause of ALF: 58% (30) of 52 patients with ALF had a thoracic injury, which was true of only 30% of the non-ALF group (P less than 0.05). 33 (or 89%) of the ALF patients with direct injury developed ALF less than 72 h after injury (early ALF), and only 11% (4) later than 72 h after injury (late ALF). Indirect injury of the lung was present in 22% (12) of the patients with posttraumatic ALF. Indirectly induced ALF occurred in less than 72 h in 36% (4) and more than 72 h after injury in 64% (7) trauma patients. PMVP was determined in 21 of the 30 patients with thoracic injury. Initial evaluation of these patients with direct induced ALF showed significantly elevated (P less than 0.01) PMVP for the traumatized (PMVPI = 10.8 +/- 5.1%/h) but normal values for the nontraumatized lung (PMVPI = 3.9 +/- 3.4%/h), whereas 4 days later the PMVP increased significantly (P less than 0.05) on the primarily healthy side (PMVPI = 8.0 +/- 5.0%/h) while remaining elevated for the traumatized lung (PMVPI = 10.9 +/- 6.0%/h). In the control group the PMVPI was 2.6 +/- 2.8%/h for the right and 2.0 +/- 2.8%/h for the left lung. Similar values were found in mechanically ventilated ICU patients without ALF. DISCUSSION. Direct injury seems to be the dominant mechanism for early manifestation (less than 72 h) of posttraumatic ALF. The thoracic trauma seems to damage the pulmonary endothelium directly, thus increasing PMVP in a circumscribed region. An overwhelming inflammatory response may cause the later increase in PMVP in the primarily healthy lung areas.


Subject(s)
Respiratory Insufficiency/epidemiology , Thoracic Injuries/epidemiology , Acute Disease , Adult , Aged , Austria/epidemiology , Capillary Permeability/physiology , Erythrocytes , Humans , Indium Radioisotopes , Lung/diagnostic imaging , Middle Aged , Prospective Studies , Radionuclide Imaging , Respiratory Insufficiency/etiology , Respiratory Insufficiency/physiopathology , Technetium , Thoracic Injuries/complications , Transferrin
15.
Anaesthesist ; 39(10): 535-9, 1990 Oct.
Article in German | MEDLINE | ID: mdl-2278374

ABSTRACT

In patients with multiple injuries, the development of permeability edema can be assumed. However, no uniform shape of this fluid accumulation can be found even in the presence of severe injuries. Based on the first clinical observations, our aim was to search for correlations between the development of extravascular lung water (EVLW) and the individual injury pattern in severely traumatized ICU patients. PATIENTS and METHODS. Our investigations were performed in 48 artificially ventilated ICU patients. According to the prevailing injury pattern patients were divided into three groups: group A: 18 patients (mean age: 32 years, mean Injury Severity Score (ISS) = 29) with isolated thoracic trauma; group B: 10 patients (mean age: 27 years, mean ISS = 42) with severe multiple trauma but without any thoracic injury; group C: 20 patients (mean age: 33 years, mean ISS = 43) with severe multiple trauma and concomitant thoracic trauma. In all patients (group A, B, C), EVLW was determined by means of a double indicator method on a daily basis from the patient's admission to the ICU (day of trauma) until day 10. Additionally, the hemodynamic parameters (heart rate, mean arterial pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure and cardiac index) were determined at the same time. RESULTS. As shown in Fig 1, EVLW was slightly elevated on day 1. However, on day 2 EVLW decreased within normal values and remained in that range until the end of the observation period. On day 3 a slight and fleeting increase of EVLW, but within normal range, can be seen. In group B (Fig.2), EVLW can be observed within normal range within a period of 4 days. Starting from day 5 until day 7 a marked increase (p greater than 0.01) in EVLW can be seen. From that maximum point EVLW development reverses slightly until day 10--however, without returning to the normal range. In group C, a marked biphasic pattern can be seen due to EVLW maximum values on post-traumatic days 3 and 7. However, in this group the EVLW was in the pathological range during the whole observation period. No statistically significant differences could be seen, when looking at hemodynamic variables. CONCLUSION. Isolated thoracic trauma will not lead to a marked pathological elevation of EVLW within the lungs. Moreover, EVLW decreases rapidly within a short time period. Based on our results, it seems that severe extrathoracic injuries will intensify microvascular injury in the initial period, as shown in our patients in group C. Increase of EVLW at a later time (day 7), as observed in groups B and C, is possibly the expression of a mediator and activator-induced "septiformal" injury of the microvascular endothelium. This may be caused by the underlying massive peripheral soft-tissue trauma. Specific elevations of EVLW subsequent to the individual injury pattern can indicate that that process has begun and is responsible for the origin of the microvascular injuries.


Subject(s)
Critical Care , Extravascular Lung Water/physiology , Multiple Trauma/physiopathology , Thoracic Injuries/physiopathology , Adolescent , Adult , Aged , Female , Hemodynamics/physiology , Humans , Male , Middle Aged
17.
Anaesthesist ; 38(9): 452-8, 1989 Sep.
Article in German | MEDLINE | ID: mdl-2686487

ABSTRACT

Two modes of combining spontaneous breathing and mechanical ventilation are already in use: periodic mechanical support always followed by a period of spontaneous breathing (intermittent mandatory ventilation; IMV) and mechanical support of each spontaneous breath (inspiratory assistance; IA). Biphasic positive airway pressure (BIPAP), in contrast, is based on neither of the above mentioned principles. It is rather a mixture of pressure controlled (PC) ventilation and spontaneous breathing, which is unrestricted in each phase of the respiratory cycle. The BIPAP circuit switches between a high (Phi) and a low (Plo) airway pressure level in an adjustable time sequence. At both pressure levels the patient can breathe spontaneously in a continuous positive airway pressure system (CPAP). The volume displacement caused by the difference between Phi and Plo and the BIPAP frequency (F) contribute the mechanical ventilation to total ventilation. Duration of the Phi and the Plo phases can be independently adjusted. Similar to the I:E ratio during controlled ventilation, the phase time ratio (PhTR) is calculated as the ratio between the durations of the two pressure phases. A PhTR greater than 1:1 is called IR-BIPAP. A BIPAP system can be set up either as a continuous flow system, or as a demand valve system. A continuous-flow BIPAP system consists of a high-flow CPAP system, a reservoir bag, and a pneumatically controlled membrane valve in the expiratory limb. A magnetic valve operated by an impulse generator switches between Phi and Plo, controlling the pop-off pressures of the expiratory valve.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Intermittent Positive-Pressure Breathing/instrumentation , Positive-Pressure Respiration/instrumentation , Humans , Intermittent Positive-Pressure Breathing/methods , Intermittent Positive-Pressure Ventilation/instrumentation , Intermittent Positive-Pressure Ventilation/methods
18.
Br J Anaesth ; 63(7 Suppl 1): 53S-58S, 1989.
Article in English | MEDLINE | ID: mdl-2514781

ABSTRACT

We have examined the effect of varying end-expiratory lung volume on carbon dioxide elimination in 10 mongrel dogs undergoing conventional mechanical ventilation at 12 b.p.m. and forced diffusion ventilation (FDV) at 6 Hz and 50 Hz and continuous flow. End-expiratory volumes were altered by changing the pressure in a plethysmographic box in which the dogs underwent ventilation. The pressures studied were atmospheric, sub-atmospheric (box pressure -1.0 kPa) and increased atmospheric (box pressure + 0.5 kPa). The results indicated that more carbon dioxide was eliminated at low lung volumes and this was most pronounced with HFV at 50 Hz and continuous flow. It is postulated that changes in airway geometry and different lung volumes may alter the distance between the gas interface in the conductive airways and the respiratory zone and so alter the efficiency of ventilation during FDV.


Subject(s)
Carbon Dioxide/physiology , High-Frequency Ventilation , Lung/physiology , Anesthesia , Animals , Dogs , Lung Volume Measurements , Respiration, Artificial , Respiratory Mechanics/physiology
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