Biomedical subjects
Publications and source records attributed to P Nikki.
A 53-yr-old woman with mediastinitis after thymectomy for myasthenia gravis was successfully mechanically ventilated with airway pressure release ventilation (APRV), which was started when the patient was intubated and continued by mask for 2 days after extubation. Mask APRV allowed efficient mechanical ventilation.
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The therapeutic efficacy of continuous positive airway pressure (CPAP) administered by face mask was studied in 40 patients with acute cardiogenic pulmonary edema and respiratory failure. Arterial blood gas values and pH, systemic arterial pressure, heart rate and respiratory rate were measured during administration of 30% oxygen with a high-flow face mask apparatus at ambient airway pressure. Twenty patients were then randomly chosen to continue ambient airway pressure breathing and 20 received 10 cm H2O of CPAP. The measurements were repeated 10, 60 and 180 minutes after therapy was initiated. During the first 10 minutes of CPAP treatment, arterial blood oxygen partial pressure increased 8 +/- 9 mm Hg (mean +/- 1 standard deviation), (p less than 0.01) and respiratory rate decreased 5 +/- 5 breaths/min (p less than 0.001). Systolic arterial pressure decreased 12 +/- 21 mm Hg (p less than 0.05), and heart rate by 10 +/- 11 beats/min (p less than 0.001). A decrease in respiratory rate by 2 +/- 5 breaths/min (p less than 0.05) was the only change that occurred in the control group. The improvement in arterial blood oxygenation persisted throughout the investigation period (p less than 0.05). Thirteen patients (65%) in the control group and 7 patients (35%) in the CPAP group met our criteria for treatment failure during the study (p = 0.068). Thus, CPAP administered by face mask improves gas exchange, decreases respiratory work, unloads circulatory stress, and may reduce the need for ventilator treatment in acute cardiogenic pulmonary edema.
The cardiopulmonary effects of continuous positive airway pressure (CPAP) were studied in 14 patients with acute myocardial infarction complicated by circulatory and respiratory failure. Cardiac performance, lung mechanics, and gas exchange were assessed during 50 percent mechanical ventilatory support at end-expiratory airway pressure levels of 0, 5, 10, and 15 mm Hg. The increase in airway pressure resulted in significantly improved arterial blood oxygenation (p less than 0.001) and in a substantial reduction in the spontaneous respiratory effort (p less than 0.001). We observed a slight decrease in stroke volume index (p less than 0.05) with increasing airway pressure in patients who had moderate left ventricular dysfunction, and a trend of improvement (NS) in those who had severe pump failure. Relatively high levels of CPAP can be used to improve pulmonary function in patients with acute myocardial infarction and left ventricular failure. In fact, circulatory depression is less likely to occur when cardiac performance is poor.
Thirty-five patients with acute fulminant (hemorrhagic) pancreatitis, verified at laparotomy, were allocated to either pancreatic resection (18 patients) or peritoneal lavation (17 patients) therapy groups. Pancreatic resection was carried out by removing the distal pancreas well cephalad to the portal vein. For peritoneal lavation, two inlet silicone catheters were inserted at laparotomy around the pancreas and an outlet catheter was inserted in the lower abdomen, and the peritoneal cavity was thereafter lavated (1000 ml/hr) with a standard peritoneal dialysis fluid for 7 to 12 days (or until death if met earlier). In other respects, the postoperative care was similar, including intravenous fluids with total parenteral nutrition until oral intake of food was resumed, prophylactic antibiotics (tobramycin and clindamycin) and stress ulcer prophylaxis (cimetidine and antacids). In the resection group, four of the 18 patients (22.2%) died, while in the lavation group eight of the 17 patients (47.1%) died. The most common cause of death was septic complications with multiple organ failure, but one patient in each group died accidentally of airway complications. There was no difference in the incidence of septic complications (sepsis and/or intra-abdominal abscesses), but the incidence and severity of pulmonary and renal complications were greater in the lavation group. However, these complications accumulated to patients who ultimately died. Also, the need for reoperation was greater in the lavation group (20 reoperations/10 patients versus 12 reoperation/eight patients). Yet, the length of overall hospital stay was equal in the two groups. Six of the 14 survivors in the resection group developed diabetes, whereas none of the nine survivors in the lavation group got this complication. The results suggest that pancreatic resection is superior to peritoneal lavation in the management of acute fulminant (hemorrhagic) pancreatitis, decreasing mortality and affording smoother postoperative course. However, these benefits are gained at the expense of higher incidence of postoperative diabetes.
Enterobacterial common antigen is a highly immunogenic component of the Gram negative bacterial cell wall that is common to all enteric bacteria. In the present study, the humoral antibody response against enteric bacteria was investigated by measuring antibodies to enterobacterial common antigen in paired serum samples in 38 patients with acute pancreatitis and in 31 healthy subjects. In mild pancreatitis (11 patients), no changes in anti-enterobacterial common antigen titres were observed as compared with healthy controls. Nine of the 10 patients had a significant increase (greater than or equal to 8 times) in anti-enterobacterial common antigen titres during the disease. Similarly, in patients with fulminant (haemorrhagic) pancreatitis who survived, a significant increase in anti-enterobacterial common antigen titres occurred during the course of the disease (in nine of the 11 patients). Paradoxically, only one of the six patients with fulminant pancreatitis with fatal outcome showed a significant increase in his anti-enterobacterial common antigen titre. The results suggest that Gram negative bacterial components escape into the systemic circulation in acute pancreatitis. This may have pathophysiologic significance in this disease.
We need objective and reliable ways of measuring the severity of disease of hospitalized patients. This paper demonstrates the international predictive accuracy of a severity of disease measure on 1504 consecutive, unscheduled intensive care admissions to 14 hospitals in the United States, France, Spain, and Finland. Using laboratory data gathered within 24 hours of ICU admission, the Acute Physiology Score of APACHE (Acute Physiology and Chronic Health Evaluation) was a strong and stable predictor of hospital survival and concurrent therapeutic effort. In ordinary least squares and logistic multiple regression analysis, the impact of the Acute Physiology Score (APS) was highly significant (p less than 0.001) and of virtually identical magnitude in the United States and European hospitals. The use of this severity of disease measure should help researchers gain insights concerning the efficacy of medical services and the characteristics of physician decision making by permitting more precise prognostic stratification of severely ill patients.
The cardiopulmonary effects of ventilatory support were studied in 12 patients with an acute myocardial infarction complicated by respiratory failure. At constant end-expiratory pressure, controlled mechanical ventilation, intermittent mandatory ventilation with 50 percent mechanical support, and spontaneous breathing all resulted in acceptable blood gas values. Intermittent mandatory ventilation offered hemodynamic advantages over controlled mechanical ventilation, as evidenced by a higher cardiac index and a lower arteriovenous oxygen content difference. Electrocardiographic evidence of myocardial ischemia was observed in one patient during controlled mechanical ventilation, in one during partial ventilatory support, and in five patients during spontaneous breathing. Myocardial ischemia should be one of the major determinants of mechanical ventilation when a patient with ischemic heart disease is subjected to ventilator treatment. The total withdrawal of ventilatory support carries a risk of marked ischemia and is not recommended until the patient can be extubated.
The "traditional" weaning criteria, arterial blood gases, and a number of other physiologic variables were measured in 47 patients to evaluate to what extent reduced ventilatory reserves or extrapulmonary organ dysfunction affect successful extubation. All patients had been weaned from continuous positive airway pressure (CPAP) and from mechanical ventilation according to the intermittent mandatory ventilation (IMV) method; at the time of study, all patients had compromised arterial oxygenation relieved by supplemental inspired oxygen. No significant difference between patients successfully extubated and those who required reintubation was found using the traditional weaning criteria or blood gases. On the other hand, patients who required reintubation had significantly lower urine volume (p less than 0.01), lower respiratory quotient values (p less than 0.05), and a higher incidence of positive blood culture (p less than 0.05). These 3 variables also correlated best to the patients' outcome after extubation.
Arterial and transcutaneous O2 (PtcO2) and CO2 (PtcCO2) tensions, arterial O2 saturations (SaO2) and P50 values were measured in 47 patients before extubation. In order to unmask ventilation to perfusion (VA/Q) inequality, all variables were obtained without CPAP and with FIO2 of 0.40 as well as with CPAP of 5 cm H2O and FIO2 of 0.40, 0.35, 0.30, 0.25, and 0.21. Eighty to 90% of the patients had PaO2/FIO2 lower than 300 torr and no significant difference in PaO2 or SaO2 was found between those who were successfully extubated (group S, n = 38) and those who required reintubation (group R, n = 9). On the other hand, the patients in group R had significantly lower P50 values, and their PtcO2 values decreased at a greater incline with the lowering of FIO2 than those in group S. Pulmonary dysfunction does not solely explain the need for reintubation in group R. It is obvious that arterial hypoxemia may become more dangerous when the patient has a low P50, anemia, or hypermetabolism. Because PtcO2 seems to uncover these factors, it is a valuable method for predicting the patient's condition before extubation.
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Twenty-three patients with acute fulminant pancreatitis were studied. The diagnosis was confirmed at laparotomy in every case. Blood samples for the assay of phospholipase A2 were collected for 14 days, and the pulmonary status of the patients was followed by monitoring the blood gases and the inspired oxygen fraction and studying a derived variable, the alveolar to arterial oxygen tension difference--the arterial oxygen tension ratio (A--aDo2/PaO2). The serum phospholipase A2 activities correlated with the changes in pulmonary function and with the outcome of the disease. Eight patients succumbed and they showed higher phospholipase A2 activities and A--aDo2/PaO2 ratios than the five patients who survived after major complications and the ten patients who survived without major complications. The results suggest that in acute fulminant pancreatitis serum phospholipase A2 activity correlates with the severity of the pulmonary changes. Furthermore, it seems to reflect the prognosis.
Positive end-expiratory pressure of 10 cm H2O (PEEP10) was compared with zero-end-expiratory pressure (PEEP0), intermittent mandatory ventilation (IMV), 4/min, with intermittent positive pressure ventilation (IPPV), 12/min, in 9 patients with pulmonary edema due to acute myocardial infarction (AMI). Systemic and pulmonary arterial pressures, pulmonary capillary wedge pressure (PCWP) and CVP, cardiac output (CO) and blood gases were measured during these four experimental interventions, and related parameters calculated. PaCO2 was 39.3 +/- 0.9 torr during IMV4 and 36.2 +/- 1.3 torr during IPPV12, and PCWP remained between 20-30 mm Hg throughout the study. The ventilatory pattern was changed at random order with the patient serving as his own control. Both PaO2 and PaO2/F102 and VO2 increased while venous admixture (Qsp/Qt) decreased with PEEP10. Cardiac and stroke indices (CI, SI) and oxygen delivery were lower with IPPV12 than they were with IMV4. Both left and right ventricular stroke work (LVSW, RVSW) were higher on IMV4. A moderate PEEP level (up to 10 cm H2O) seems beneficial in post-AMI pulmonary edema and has no significant hemodynamic side effects. The results indicate that of the four alternatives studied, IMV4 with PEEP10 is a ventilatory pattern of choice in the respiratory management of these patients, but each individual patient may require precise titration of each modality to achieve the optimal result.
Transcutaneous oxygen and carbon dioxide tensions (PtcO2 and PtcCO2) were compared with PaO2 and PaCO2 values in 9 patients with pulmonary edema due to acute myocardial infarction (AMI) measured during four experimental interventions: (a) intermittent mandatory ventilation (IMV) 4/min + PEEP0 (cm H2O); (b) intermittent positive pressure ventilation (IPPV)12 + PEEP0; (c) IMV4 + PEEP10; and (d) IPPV12 + PEEP10. PtcO2 responded rapidly to the institution of PEEP, the rise correlating well with that in PaO2 both on IMV4 (r = 0.78) and IPPV12 (r = 0.87). On the other hand, correlations between PtcO2 vs CI and PvO2 were poor (r being 0.45 and 0.24, respectively). Transcutaneous oxygen electrode is, thus, useful in monitoring patients with post-AMI pulmonary edema, as it rapidly reflects the effects of ventilatory therapy. A nonheated PtcCO2 sensor was used in 6 patients and a heated electrode in 3 patients. With the nonheated electrode, the correlation between PaCO2 and PtcCo2 was good (r = 0.86) in 5 patients, while r in the 3 patients with the heated electrode was 0.73. One patient having a cardiac index of 1.6 L/min . M2 showed a dissociation in PCO2 values. While PaCO2 remained unchanged, PtcCO2 rose to 73 torr and within some minutes the patient had asystole. PtcCO2 tension generally shows good correlation with PaCO2 and, thus, reflects ventilation. It may also prove to be useful in the early detection of critical low cardiac output states.
An unusual, severe pneumonia probably caused by varicella-zoster virus is reported in a 19-year-old previously healthy man. The diagnosis was based on high titer of varicella-zoster antibodies in serum, and demonstration of varicella-zoster antigen from lung biopsy specimen. The uncommon feature in the pathophysiological course of the disease was the selective hypercarbia that responded well to bronchodilator therapy with theophylline. Furthermore, the patient had no skin manifestations during his illness.
To estimate the value of central venous blood as representative of real changes in pulmonary shunt (Qsp/Qt), mixed venous oxygen saturation and arteriovenous oxygen content difference [C(a-v)O2] during active phases of adult intensive care therapy, 86 blood samples were withdrawn from 42 patients as quadruple simultaneous collections from systemic artery, pulmonary artery (PA), superior caval vein (CV) and right atrium (RA). We found a significant positive correlation of the measured variables and especially of the subsequent changes of these variables in individual patients between PA blood samples and both CV and RA blood samples (p less than 0.001). We, therefore, conclude that a central venous catheter can replace the PA catheter to collect blood representative of mixed venous blood samples for the above purposes. However, the exact numerical value of mixed venous blood samples can only be measured from blood collected from the PA itself.
Respiratory failure in a patient with acute myocardial infarction requires immediate attention in an attempt to prevent extension of the myocardial injury. Therapy should be based on a thorough cardiorespiratory analysis and careful monitoring, because erroneous decisions may have serious consequences when the circulation is marginal. If the patient is connected to a ventilator, a low IMV rate is haemodynamically preferable to CMV. Moderate PEEP can and should be used to decrease venous admixture and to increase lung compliance when needed. Face mask CPAP may, in some cases, make endotracheal intubation unnecessary.