Influence of mechanical ventilation and pulmonary disease on pulmonary artery pressure monitoring

Mechanical ventilation and respiratory disease impose both theoretical and practical limitations on the interpretation of hemodynamic measurements. To properly interpret such information a thorough understanding of the circulatory changes associated with normal breathing, mechanical ventilation and respiratory disease is vital. There are a variety of factors involved in patients with obstructive lung disease and those receiving mechanical ventilation that complicate the usual interpretation of hemodynamic data obtained from flow-directed catheters. An awareness of the potential pitfalls of hemodynamic monitoring in such situations is important in the efficient use of the hemodynamic data obtained.

Primary alveolar hypoventilation managed by negative-pressure ventilators

A girl who had a history of repeated apnea was found to have absent chemical drive to ventilation and, on sleep monitoring, both central and obstructive types of apnea. She is currently undergoing successful mechanical ventilation at night with negative-pressure ventilators.

Severe thrombocytopenia probably due to acute folic acid deficiency

Thirteen patients with significant hemorrhage, severe thrombocytopenia, and megaloblastic bone marrows are described. Unusual features of this problem included its acute onset, frequent absence of the typical peripheral blood changes of megaloblastic anemia, normal serum B12 levels, and serum folates which were often not clearly abnormal. Most patients were critically ill and common clinical features included reduced dietary intake, renal failure, renal dialysis, the postoperative state, and sepsis. These clinical features, the laboratory findings, and a platelet increase in most patients after folate therapy lead to the conclusion that this problem is probably due to acute folic acid deficiency. Possible explanations for the atypical laboratory findings include the acuteness of onset, recent blood transfusion therapy, and impaired folate utilization. This problem may be relatively common. Because of its potential clinical importance, rapid onset, and attendent diagnostic difficulties, prophylactic folic acid is recommended in the clinical setting described.

Hydrogen sulfide poisoning: review of 5 years' experience

The workforce of Alberta, a province rich in fossil fuel, faces an increasing risk of exposure to hydrogen sulfide (H2S). Basic knowledge of the population exposed during the years 1969 to 1973 inclusive was accumulated to identify the immediate medical and management problems. Data were recorded from three sources of records: the Workers' Compensation Board of Alberta, the Alberta Hospital Services Commission and the provincial coroner's office. There were 221 cases of exposure to H2S. The overall mortality was 6%; 5% of victims were dead on arrival at hospital. Admission to hospital was required for 65% of the victims arriving at a hospital emergency room (78% of the 221). Acute problems were coma, dysequilibrium and respiratory insufficiency with pulmonary edema. Increased attention to cardiopulmonary resuscitation at the exposure site and during transportation to hospital is necessary to reduce the mortality from H2S exposure. No long-term adverse effects were apparent in the survivors.

Percutaneous trephine lung biopsy: evolving role

The Steele trephine was employed to perform 134 transthoracic biopsies in 120 patients. Resultant cores of tissue and "lung juice" provided a diagnosis in 89 percent (107) of the patients. Complications occurred in 41 percent (49) of the patients, the incidence being greatest in those with diffuse parenchymal disease. Most complications were of a minor nature. Although the precise role of trephine lung biopsy in the physician's diagnostic armamentarium remains to be defined, there is no doubt that it is a useful and safe technique in the elucidation of intrathoracic disease.

Fatal pseudomembranous enterocolitis following clindamycin therapy

A fatal case of pseudomembranous enterocolitis following oral and parenteral clindamycin therapy is presented. Interesting features in this case are involvement of the small bowel and complete sparing of the large bowel distal to a defunctioning transverse colostomy. The significance of the absence of disease in the defunctioned bowel is discussed in terms of aetiology and diagnosis of pseudomembranous enterocolitis.

A prospective study of complications after tracheostomy for assisted ventilation

A prospective study of 40 patients having elective tracheostomy for ventilatory assistance used fiberoptic bronchoscopy and radiologic examination to assess tracheal healing after extubation. Ten percent of patients had bleeding complications of tracheostomy and 17.5 percent had tracheostomy management problems. Sixteen percent of survivors had asymptomatic stomal site tracheal narrowing and 8 percent required tracheal resection for symptomatic stomal site tracheal stenosis, 16 percent had asymptomatic tracheal defects at the cuff site. Stomal healing was seen to consist of gradual stomal shrinkage, resolution of tracheitis, and approximation of divided tracheal rings. No statistically significant correlation was demonstrated between various factors operative during ventilatory assistance and subsequent tracheal healing. All patients should have routine endoscopic or radiologic tracheal assessment after-tracheostomy.

Fatal cardiac tamponade and other mechanical complications of central venous catheters

A fatal cardiac tamponade caused by an intact polyethylene central venous catheter perforating the wall of the right ventricle is reported. A retrospective review of 105 central venous catheters used in an intensive care unit revealed a high incidence of catheter malposition and a 20 per cent mechanical complication rate. The possible causes of these malpositions and complications are discussed. Guidelines for the safer use of central venous catheters are presented.

Trephine lung biopsy

Forty-five percutaneous trephine lung biopsies using the Steel apparatus were performed on 38 patients. Tissue was obtained on 42 occasions (94%) leading to histological or culture diagnosis in 33 patients (87%). Pneumothoraces (12 patients), bleeding into the airways or pleural space (4 patients), and tumour seeding along the needle track (1 patient) occurred in 38% of biopsy attempts (45% of patients). In contrast to the Vim-Silverman technique, the Steel trephine appears to produce a higher tissue yield and superior specimens for histological study. Trephine lung biopsy is comparable to open lung biopsy in providing positive diagnoses. With anticipation and expeditious management of complications, trephine lung biopsy is both safe and useful in the diagnosis of pulmonary disease.

Adult respiratory distress syndrome

The adult respiratory distress syndrome is a condition of progressive respiratory failure that is being recognized with increasing frequency in patients hospitalized for a variety of reasons. Recognition of the syndrome and anticipation of its occurrence leads to the correct management of these patients.