Views and understanding of senior nursing staff in relation to infection control

ittle research has been conducted into the broad themes of the factors that encourage nurses to comply with infection control procedures — experimental approaches have dominated previous research. A qualitative study into the views and understanding of senior nurses related to infection control procedures was undertaken at a large district general hospital.

This paper looks at a number of themes, which emerged as important bases for compliance with infection control procedures. This included the importance of role models, leadership, efficacy of link groups and communication links.

Adolescent inhalant use and executive cognitive functioning

BACKGROUND

This study investigates the association between inhalant use and executive cognitive functioning (ECF) and processing speed (PS) in 754 adjudicated poly-substance users on a series of neuropsychological tests. Poly-substance users who used inhalants (PSI = 262) and poly-substance users who did not use inhalants (PSO = 492) neuropsychological tests scores were compared. Hispanic Americans comprised 72% of the participants; European Americans, African Americans and Asian Americans comprised 28% of the participants.

METHODS

Standardized neuropsychological tests were used to assess ECF and PS. Psychosocial and substance abuse standardized surveys were used to assess drug use severity and psychosocial problems associated with substance use.

RESULTS

Multiple Analysis of Covariance shows that PSI users who used inhalants performed worse on ECF and PS measures in comparison to non-inhalant poly-substance users (PSO). PSI users were younger, used more drugs and had more psychiatric admissions than PSO users.

CONCLUSION

PSI users initiate substances at a younger age and experienced more ECF and PS deficits, and behavioural problems in comparison to PSO users. The results of this study suggest that PS has direct effect on ECF and psychosocial outcomes in PSI users.

An examination of information-processing skills among inhalant-using adolescents

BACKGROUND

This study investigates the association between inhalant use and information processing (IP) in adjudicated polysubstance users. Polysubstance users who used inhalants (n= 158) were compared with polysubstance users who did not use inhalants (n= 303). Hispanic Americans comprised 72% of the participants; European Americans, African Americans and Asian Americans comprised 28% of the participants.

METHOD

  Standardized intelligence and achievement tests were used to assess information-processing constructs of working memory and processing speed. Psychosocial and substance abuse standardized surveys were used to assess drug use severity and psychosocial problems associated with substance use.

RESULTS

Polysubstance users who used inhalants (PSI users) were younger, used more drugs more frequently and had more psychiatric admissions than non-inhalant polysubstance users (PSO users). Statistical analysis also shows that PSI users performed worse on measures of IP selected tests in comparison with the PSO users.

CONCLUSION

Inhalant users begin abusing substances at a younger age and suffer from more verbal and non-verbal processing, behavioural, language and memory problems than non-inhalant users.

Matrix metalloproteinase abundance in human myocardial fibroblasts: effects of sustained pharmacologic matrix metalloproteinase inhibition

BACKGROUND

A cause-effect relationship has been established between matrix metalloproteinases (MMPs) and left ventricular (LV) myocardial remodeling through the use of pharmacologic MMP inhibitors. However, the direct effects of MMP inhibition on MMPs and endogenous tissue inhibitors of metalloproteinases (TIMPs) in LV human myocardial fibroblasts (LVHMFs) remain unknown. This study measured MMP-2, MMP-9, MMP-13, MT1-MMP, and TIMP-1 release in LVHMFs.

METHODS AND RESULTS

LVHMF cultures were established from six individual patients (passages 2-5) and incubated with and without the broad-spectrum MMP inhibitor PD166793 (100 microM) for 12-36 h. While PD166793 did not influence MMP-2 release, MMP-9 levels based on substrate zymography increased at 36 h by over 30% (P < 0.05). TIMP-1 levels increased in a time-dependent manner with no effect from PD166793 incubation. However, the MMP-9/TIMP-1 ratio was increased by over 20% from time-matched values following 12-36 h of exposure to PD166793 (P < 0.05). Similar results obtained after incubation of LVHMF cultures with the broad-spectrum MMP inhibitor Batimastat (BB-94) suggest that these observations are due to a general class effect of broad-spectrum MMP inhibitors.

CONCLUSIONS

This study is the first to demonstrate that a selective induction and release of an MMP species occurs with sustained exposure to pharmacologic MMP inhibition in LVHMFs. These observations may have particular importance with respect to controlling this proteolytic system in the context of LV myocardial remodeling.

Matrix metalloproteinase inhibition modifies left ventricular remodeling after myocardial infarction in pigs

BACKGROUND

Global and regional shape changes that occur within the left ventricular wall after myocardial infarction have been termed infarct expansion. A potential mechanism for this postinfarction remodeling is activation of the matrix metalloproteinases. Accordingly, the present study examined the effects of matrix metalloproteinase inhibition on left ventricular global geometry after myocardial infarction in pigs.

METHODS

Myocardial infarction was created in pigs by means of occlusion of the first and second obtuse marginal branches of the circumflex coronary artery, resulting in a uniform left ventricular free wall infarct size of 21% +/- 2%. At 5 days after infarction, the pigs were randomized to undergo broad-spectrum matrix metalloproteinase inhibition (n = 9; PD166793, 20 mg. kg(-1). d(-1) by mouth) or myocardial infarction alone (n = 8). Ten pigs served as noninfarction control animals. Left ventricular end-diastolic area, determined by means of echocardiography, was measured 8 weeks after infarction.

RESULTS

Left ventricular end-diastolic area increased in both the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition and myocardial infarction only groups compared to reference control animals (3.7 +/- 0.2 cm(2)), but was reduced with broad-spectrum matrix metalloproteinase inhibition compared to myocardial infarction alone (4.5 +/- 0.2 vs 4.9 +/- 0.2 cm(2), respectively; P <.05). Regional radial stress within the infarct region increased in both infarction groups when compared to values obtained from reference control animals (599 +/- 152 g/cm(2)), but was attenuated in the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition group compared to the myocardial infarction alone group (663 +/- 108 vs 1242 +/- 251 g/cm(2), respectively; P <.05). Similarly, regional myocardial stiffness increased in both the myocardial infarction plus broad-spectrum matrix metalloproteinase inhibition and the myocardial infarction only groups compared with that observed in reference control animals (14 +/- 1 rkm, P <.05) but was lower with broad-spectrum matrix metalloproteinase inhibition than with myocardial infarction alone (42 +/- 6 vs 68 +/- 10 rkm, respectively; P <.05).

CONCLUSIONS

Matrix metalloproteinase inhibition reduced postinfarction left ventricular dilation, reduced regional myocardial wall stress, and modified myocardial material properties. These unique findings suggest that increased myocardial matrix metalloproteinase activation after infarction contributes directly to the left ventricular remodeling process.

Myocardial infarct expansion and matrix metalloproteinase inhibition

BACKGROUND

A potential mechanism for left ventricular (LV) remodeling after myocardial infarction (MI) is activation of the matrix metalloproteinases (MMPs). This study examined the effects of MMP inhibition (MMPi) on regional LV geometry and MMP levels after MI.

METHODS AND RESULTS

In pigs instrumented with radiopaque markers to measure regional myocardial geometry, MI was created by ligating the obtuse marginals of the circumflex artery. In the first study, pigs were randomized to MMPi (n=7; PD166793, 20 mg x kg(-1) x d(-1)) or MI only (n=7) at 5 days after MI, and measurements were performed at 2 weeks. Regional MI areas were equivalent at randomization and were increased in the MI-only group at 2 weeks after MI compared with the MMPi group. In the second study, pigs randomized to MMPi (n=9) or MI only (n=8) were serially followed up for 8 weeks. At 8 weeks after MI, LV end-diastolic dimension was lower with MMPi than in the MI-only group (4.7+/-0.1 versus 5.1+/-0.1 cm, P<0.05). Regional MI area was reduced with MMPi at 8 weeks after MI (1.3+/-0.1 versus 1.7+/-0.1 cm2, P<0.05). MMPi reduced ex vivo MMP proteolytic activity. In the MI region, membrane-type MMP levels were normalized and levels of the endogenous tissue inhibitor of MMPs (TIMP-1) were increased compared with normal levels with MMPi. These effects were not observed in the MI-only group.

CONCLUSIONS

MMPi attenuated the degree of post-MI LV dilation and expansion of the infarct during the late phase of MI healing. In addition, exogenous MMPi caused region-specific modulation of certain MMP and TIMP species.

TNF-alpha and myocardial matrix metalloproteinases in heart failure: relationship to LV remodeling

The cytokine tumor necrosis factor (TNF)-alpha has been causally linked to left ventricular (LV) remodeling, but the molecular basis for this effect is unknown. Matrix metalloproteinases (MMPs) have been implicated in cardiac remodeling and can be regulated by TNF-alpha. This study tested the central hypothesis that administration of a TNF-alpha blocking protein would prevent the induction of MMPs and alter the course of myocardial remodeling in developing LV failure. Adult dogs were randomly assigned to the following groups: 1) chronic pacing (250 beats/min, 28 days, n = 12), 2) chronic pacing with concomitant administration of a TNF-alpha blocking protein (TNF block) using a soluble p75 TNF receptor fusion protein (TNFR:Fc; administered at 0.5 mg/kg twice a week subcutaneously, n = 7), and 3) normal controls (n = 10). LV end-diastolic volume increased from control with chronic pacing (83 +/- 12 vs. 118 +/- 10 ml, P < 0.05) and was reduced with TNF block (97 +/- 9 ml, P < 0.05). MMP zymographic levels (92 kDa, pixels) increased from control with chronic pacing (36,848 +/- 9,593 vs. 87,247 +/- 12,912, P < 0.05) and was normalized by TNF block. Myocardial MMP-9 and MMP-13 levels by immunoblot increased with chronic pacing relative to controls (130 +/- 10% and 118 +/- 6%, P < 0.05) and was normalized by TNF block. These results provide evidence to suggest that TNF-alpha contributes to the myocardial remodeling process in evolving heart failure through the local induction of specific MMPs.

Psychosocial predictors of satisfaction among orthognathic surgery patients

This study assessed the usefulness of selected psychosocial tests and demographic measures in identifying satisfied versus dissatisfied patients who received orthognathic surgery. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, 12 months and and 2 years postsurgery. The Revised Symptom Checklist-90 (SCL-90-R) scales, the Eysenck Personality Inventory (EPI), the Sickness Impact Profile (SIP), and the Oral Health Status Questionnaire (OHSQ) were used as independent variables. Indicators from the Post-Surgical Patient Satisfaction Questionnaire (PSPSQ), which assesses patient satisfaction regarding psychosocial issues, oral functioning, and esthetics, served as a postsurgical dependent measure of patient satisfaction. Thirty-one male and 86 female subjects participated in the multisite randomized trial comparing rigid and wire fixation. Patient age was significantly correlated with patient satisfaction from 8 weeks postsurgery through 2 years postsurgery. Older patients appear to report greater postsurgical satisfaction in comparison to younger patients. The postsurgical OHSQ (esthetics subscale) and postsurgical PSPSQ (satisfaction) were significantly related at 8 weeks, 6 months, 12 months, and 2 years postsurgery. Additionally, PSPSQ (satisfaction) and postsurgical OHSQ (general oral health scale) were correlated at 12 months. The EPI, SIP, and SCL-90-R were not significantly associated with postsurgical satisfaction when assessing the entire study sample. Postsurgical qualitative data from the PSPSQ indicated that 50% of the patients reported positive outcomes in oral functioning. Sixty-five percent reported esthetic improvements, and 37% reported neurosensory loss.

Psychosocial predictors of high-risk patients undergoing orthognathic surgery

The purpose of this analysis was to identify a set of predictor variables that are prospectively related to postsurgical outcomes. Specifically, psychosocial characteristics were sought to predict postsurgical outcomes. The 5 Revised Symptom Checklist-90 (SCL-90-R) scales, the neuroticism score of the Eysenck Personality Inventory (EPI), the psychosocial domain score from the Sickness Impact Profile (SIP), and 4 scales from the Oral Health Status Questionnaire (OHSQ) were used as the predictors. A total of 31 male and 86 female subjects participated in this multicenter randomized trial, which compared rigid and wire fixation. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, and 2 years after surgery. Baseline oral health was used as an indicator of postsurgical oral health functioning. A path analytic model of influences on presurgical oral health was estimated (R2 = 0.43). The results suggest that presurgical screening of demographic characteristics (age, sex, and ethnicity), oral health (the OHSQ), quality of life issues (SIP), and personality features (SCL-90-R), accounts for 23% to 39% of the variance in postsurgical oral health outcomes. The path analysis conducted suggests that a patient's age, ethnicity, gender, and elevated scores on the EPI have indirect effects on postsurgical health. As determined by a 2-stage least squares regression model, 3 variables--the patient's presurgical oral health (per the OHSQ), pre- and postsurgical Global Severity Index (GSI) score from the SCL-90-R, and the psychosocial scale score from the SIP--were found to have a statistically significant impact on postsurgical outcomes. Additionally, the GSI, SIP, and OHSQ are reliable measures in predicting oral health outcomes.

Cutaneous Waldenstrom macroglobulinemia in transformation

Waldenstrom macroglobulinemia is a low-grade B-cell lymphoproliferative disorder of the elderly with characteristic monoclonal IgM-producing neoplastic infiltrates of the bone marrow, lymph node, and spleen. Cutaneous manifestations are usually nonspecific such as purpura, ulcers, and urticarial lesions. These lesions are caused by hyperviscosity of the blood, immune complex-mediated vascular damage, paraprotein deposition, and amyloid deposition. Specific skin lesions occur rarely and generally consist of translucent, flesh-colored papules composed of monoclonal IgM deposits. Rarely, there may be violaceous lesions composed of low-grade lymphoplasmacytic infiltrates characteristic of Waldenstrom macroglobulinemia. Both cutaneous manifestations of the disease, as well as disease transformation to high-grade, large cell lymphoma are rare. We report two very unusual cases of Waldenstrom macroglobulinemia with documented skin disease that demonstrated transformation to high-grade lymphoma. Both patients were elderly men with long-standing Waldenstrom macroglobulinemia involving the bone marrow, who subsequently developed skin involvement by the disease. Waldenstrom macroglobulinemia can rarely manifest as cutaneous disease, sometimes as a high-grade transformation of low-grade Waldenstrom macroglobulinemia elsewhere. Distinction of cases of transformed Waldenstrom macroglobulinemia from de novo cutaneous large cell lymphoma may be important, because the two entities are likely biologically different.

Clinical and molecular characterization of a rare syndrome of acute promyelocytic leukemia associated with translocation (11;17)

Analysis of a variant translocation t(11;17) in a case of acute promyelocytic leukemia (APL) led to discovery of a novel zinc finger gene, PLZF, fused to the retinoic acid receptor-alpha (RAR alpha) gene. We reviewed the clinical and molecular features of five additional patients with t(11;17)-associated APL. The clinical course of three patients was characterized by early death and three experienced disseminated intravascular coagulation. Morphologically all of the patients fell in a unusual morphologic spectrum of APL, with features intermediate between M2 and M3 AML. All six patients had PLZF-RAR alpha gene fusion as detected by reverse transcription/polymerase chain reaction assay, Southern blotting, or pulsed-field gel electrophoresis. Five of the six patients failed to achieve complete remission after initial chemotherapy or differentiation therapy with all-trans retinoic acid (ATRA). A sixth patient responded to initial chemotherapy, but on relapse failed to respond to ATRA. When tested in vitro, cultured cells from three of the patients failed to differentiate in response to ATRA. APL associated with t(11;17) and fusion of the PLZF and RAR alpha genes is a discrete clinico-pathologic syndrome with a distinctly worse prognosis than t(15;17) APL.

Hantaviruses: clinical, microbiologic, and epidemiologic aspects

Hantaviruses comprise a genus of the family Bunyaviridae. Bunyaviruses are enveloped viruses with a negative-sense, tripartite RNA genome. Hantaviruses are etiologic agents for two acute and severe illnesses of man, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Each hantavirus is primarily associated with a single rodent host species or genus, and is transmitted to man through accidental inhalation or ingestion of virus-contaminated rodent excreta. The distribution of hantaviruses is worldwide. HFRS is caused by infection with Hantaan, Seoul, Dobrava/Belgrade, and Puumala hantaviruses, all of which are enzootic in murid rodents of Old World origin. HPS is caused by any of several hantavirus species associated with indigenous New World rodents of the subfamily Sigmodontinae, family Muridae. HFRS and HPS have numerous common epidemiologic, clinical, and laboratory characteristics. Common features include fever, myalgia, thrombocytopenia, neutrophilia, and a profound capillary leak syndrome associated with hypotension, decreased cardiac output, and shock. Worldwide, HPS is much less common than HFRS but is associated with a higher mortality rate. Recovery from hantavirus disease is generally complete, although chronic renal insufficiency may be a rare sequel of HFRS.

HLA-DR-, CD33+, CD56+, CD16- myeloid/natural killer cell acute leukemia: a previously unrecognized form of acute leukemia potentially misdiagnosed as French-American-British acute myeloid leukemia-M3

We have identified and characterized a previously unrecognized form of acute leukemia that shares features of both myeloid and natural killer (NK) cells. From a consecutive series of 350 cases of adult de novo acute myeloid leukemia (AML), we identified 20 cases (6%) with a unique immunophenotype: CD33+, CD56+, CD11a+, CD13lo, CD15lo, CD34+/-, HLA-DR-, CD16-. Multicolor flow cytometric assays confirmed the coexpression of myeloid (CD33, CD13, CD15) and NK cell-associated (CD56) antigens in each case, whereas reverse transcription polymerase chain reaction (RT-PCR) assays confirmed the identity of CD56 (neural cell adhesion molecule) in leukemic blasts. Although two cases expressed CD4, no case expressed CD2, CD3, or CD8 and no case showed clonal rearrangement of genes encoding the T-cell receptor (TCR beta, gamma, delta). Leukemic blasts in the majority of cases shared unique morphologic features (deeply invaginated nuclear membranes, scant cytoplasm with fine azurophilic granularity, and finely granular Sudan black B and myeloperoxidase cytochemical reactivity) that were remarkably similar to those of acute promyelocytic leukemia (APL); particularly the microgranular variant (FAB AML-M3v). However, all 20 cases lacked the t(15;17) and 17 cases tested lacked the promyelocytic/retinoic acid receptor alpha (RAR alpha) fusion transcript in RT-PCR assays; 12 cases had 46,XX or 46,XY karyotypes, whereas 2 cases had abnormalities of chromosome 17q: 1 with del(17)(q25) and the other with t(11;17)(q23;q21) and the promyelocytic leukemia zinc finger/RAR alpha fusion transcript. All cases tested (6/20), including the case with t(11;17), failed to differentiate in vitro in response to all-trans retinoic acid (ATRA), suggesting that these cases may account for some APLs that have not shown a clinical response to ATRA. Four of 6 cases tested showed functional NK cell-mediated cytotoxicity, suggesting a relationship between these unique CD33+, CD56+, CD16- acute leukemias and normal CD56+, CD16- NK precursor cells. Using a combination of panning and multiparameter flow cytometric sorting, we identified a normal CD56+, CD33+, CD16- counterpart cell at a frequency of 1% to 2% in the peripheral blood of healthy individuals. Our studies suggest that this form of acute leukemia may arise from transformation of a precursor cell common to both the myeloid and NK cell lineages; thus we propose the designation myeloid/NK acute leukemia. Recognition of this new leukemic entity will be important in distinguishing these ATRA-nonresponsive cases from ATRA-responsive true APL.

Aggressive bladder carcinoma in an adolescent. Report of a case with immunohistochemical, cytogenetic, and flow cytometric characterization

Malignant bladder neoplasms of urothelial origin are rare among children; fewer than 125 cases have been reported. Typically, these tumors are single papillary lesions of low grade and stage that have an excellent prognosis following surgical excision. A grade III transitional cell carcinoma of the bladder occurred in a 14-year-old boy who had no urinary tract malformation, carcinogenic exposure, or family history of cancer. Immunohistochemical stains of the tumor were positive for cytokeratin and high-molecular-weight keratin. The tumor tissue failed to stain with an antibody to the patient's blood group [anti-ABO(H)] but was positive for the Thomsen-Frieden-reich antigen. Flow cytometry of the tumor cells demonstrated a diploid or near-diploid DNA content. A karyo-type of the tumor showed a modal chromosome number of 46 with one reciprocal translocation between chromosomes 17 and 22 and a nonreciprocal translocation between chromosomes 18 and 22. The tumor was unique because of its highly aggressive nature and its diploid chromosome number. This case represents the first indepth characterization of a transitional cell carcinoma in a pediatric patient by flow cytometry and cytogenetics, as well as a variety of immunohistochemical studies including ABO(H) blood group and Thomsen-Freidenreich antigens.

Cytomegalovirus retinitis

Cytomegalovirus retinitis is a frequent and serious complication of various conditions, including diseases characterized by impaired immunity, such as the acquired immunodeficiency syndrome. Due to recent advances in the treatment of cytomegalovirus retinitis, accurate diagnosis and management have become increasingly important. In this review, the authors present the epidemiology, clinical features, diagnostic testing, treatment with complications, and prognosis of cytomegalovirus retinitis. A differential diagnosis is presented and the characteristic ocular lesions are illustrated.

Neonatal renal failure: a complication of maternal antihypertensive therapy

Persistent anuria was diagnosed in a neonate born to a mother whose pregnancy was complicated by severe hypertension and systemic lupus erythematosus. Severe maternal hypertension necessitated the use of a battery of antihypertensive medications that included enalapril, an angiotensin converting enzyme inhibitor. The role of enalapril in neonatal renal failure is discussed.

The family physician - anesthetist: a review of two training programs

A considerable proportion of anesthetic services in Canada is provided by family-physician anesthetists, particularly in community hospitals and rural areas not served or not fully served by specialist anesthetists. In the 1970s, the Departments of Anesthesia of the Universities of Toronto and Western Ontario established short training programs to meet the needs of these physicians and communities. In 1983, both universities surveyed the physicians who had completed the programs to assess the characteristics of the practices of these physicians and to further discussion about the appropriate training for such settings. This paper describes the two programs for training of family-physician anesthetists and reports on the survey of trainees who have completed the programs.

Detection of cytomegalovirus in shell vial cultures by using a DNA probe and early nuclear antigen monoclonal antibody

An in situ biotinylated DNA probe assay was evaluated as an adjunct to anti-cytomegalovirus early nuclear antigen indirect immunofluorescence and cytopathic effect on cytomegalovirus-infected monolayers in shell vial cultures. Viral infection was detected by early nuclear antigen indirect immunofluorescence at 24 h and by DNA probe assay and shell vial cytopathic effect at 5 days.

Thrombosis in the upper extremity: use of Doppler ultrasound for diagnosis

A case of subclavian vein thrombosis which was not detected clinically is described. Doppler ultrasound was used to ascertain the diagnosis. The technique of examination with the Doppler method for upper limb thrombi is described. It is expected that this technique will be as valuable for detection of thrombosis in the upper extremities as it has been shown to be in lower extremities. This is important because the incidence of deep vein thrombosis has increased with the frequent use of indwelling central venous catheters and because of increased awareness of the possibility and dangerous sequelae of the thrombosis, Early detection of thrombus by this non-invasive method, with removal of the catheters and prompt heparin therapy can preserve the integrity of the venous conduits and avert emboli. This is particularly relevant for anaesthetists in critical units.

Tests for hemostasis and their relevance to venous thrombosis

The authors have tried to determine which patients were at risk of venous thrombosis. They chose 10 tests for hemostasis that might be of value in predicting those patients who were at risk. The tests were used in two groups of patients: one group in a respiratory intensive care unit and another group of patients about to undergo a major spinal operation. The tests were those for measuring: platelet count, prothrombin time, activated partial thromboplastin time, platelet thromboplastic activity (platelet factor 3), plasma clotting time, and concentrations of fibrinogen, plasminogen, antithrombin-III, alpha-1-antitrypsin and platelet fibrin degradation products (FDP). A diagnosis of thrombosis was made by three techniques: radioactive fibrinogen accumulation in the developing thrombus, impedance plethysmograhpy and ascending venography. The only test for hemostasis that discriminated between patients with and without thrombosis was the level of circulatory FDP. Several of the tests showed pronounced changes within the normal range following development of thrombosis and even before its detection. Therefore, none of the tests was truly predictive. A detailed discussion of the performance and interpretation of impedance plethysmography is presented.

Mechanical ventilation during laryngeal surgery: an evaluation of the Carden tube

The effectiveness and safety of the Carden tube-oxygen injector system for ventilation was studied in 18 high-risk patients with obstructive airways disease during microlaryngeal surgery. Blood gas studies during operation demonstrated a mean Pao2 of 65.6 kPa (493 torr) and a mean PaCO2 of 4.5 kPa (34 torr) during mechanical ventilation. No serious complications were noted during operation. Fifty per cent of the patients had postoperative hypercapnia and in two the trachea was re-intubated. Airway maintenance and ventilation are discussed in detail and it is concluded that the Carden tube-oxygen injector system is a safe and convenient method for ventilating the lungs of patients with pulmonary disease who require microlaryngeal surgery.

Aorta-coronary bypass in a patient with sickle cell trait

A triple aorto-coronary bypass was performed in a patient with sickle cell trait. Partial exchange transfusion with normal packed erythrocytes was used in preparation of the patient for extracorporeal circulation, hypothermia and cardioplegic arrest.

Thrombosis and free fatty acids in patients subjected to total hip arthroplasty

The plasma concentrations of free fatty acids were estimated at intervals before, during and after total hip arthroplasty in seven patients. Each patient underwent examination for deep vein thrombosis with iodine-125 leg scanning, impedance plethysmography and contrast venography. Substantially higher concentrations of free fatty acids were found in the plasma of patients shown to have thrombosis than in those without thrombosis.

Extracorporeal membrane oxygenator support for human lung transplantation

Extracorporeal membrane oxygenator (ECMO) support was provided for a 19-year-old boy undergoing right lung transplantation. Perfusion was begun several hours prior to transplant, to correct profound hypercapnia. After the operation, ECMO was required because of inadequate gas exchange by the transplanted lung. Perfusion was continued for a total of 96 hours. During this time, the temporary malfunction of the transplanted lung owing to the reimplantation response reversed, and the patient was successfully removed from the oxygenator and subsequently weaned from the ventilator. He died on the eighteenth postoperative day of bronchial dehiscence. ECMO support appears to be a feasible means of supporting patients during lung transplantation and during the period of reversible lung malfunction that may occur in the early postoperative period.

Selective tracheobronchial aspiration

Eighty attempts at placing suction catheters in the left main bronchus were analysed by studying chest radiographs. When angled catheters were used via a tracheostomy tube the success rate was 75%; the rate fell to 15% when straight tubes were used through an orotracheal tube. Assessment and control of the tube length was found to be important to avoid kinking and subsequent obstruction of the catheters.

Systemic infection with Alaria americana (Trematoda)

Alaria americana is a trematode, the adult of which is found in mammalian carnivores. The first case of disseminated human infection by the mesocercarial stage of this worm occurred in a 24-year-old man. The infection possibly was acquired by the eating of inadequately cooked frogs, which are intermediate hosts of the worm. The diagnosis was made during life by lung biopsy and confirmed at autopsy. The mesocercariae were present in the stomach wall, lymph nodes, liver, myocardium, pancreas and surrounding adipose tissue, spleen, kidney, lungs, brain and spinal cord. There was no host reaction to the parasites. Granulomas were present in the stomach wall, lymph nodes and liver, but the worms were not identified in them. Hypersensitivity vasculitis and a bleeding diathesis due to disseminated intravascular coagulation and a circulating anticoagulant caused his death 8 days after the onset of his illness.

Cardiorespiratory failure secondary to peripheral pulmonary emboli. Survival following a combination of prolonged extracorporeal membrane oxygenator support and pulmonary embolectomy

A 19-year-old woman developed cardiorespiratory failure from multiple, peripheral pulmonary emboli apparently developing over the preceding 3 weeks. She was not considered to be an operative candidate. However, when 3 days of intravenous heparin infusion and 30 hours of membrane oxygenator support failed to improve the pulmonary pathology, pulmonary embolectomy was performed. The membrane oxygenator support had to be continued for 34 hours following the operation before it was successfully discontinued. The patient made a complete recovery.

Combination of membrane oxygenator support and pulmonary lavage for acute respiratory failure

A 24-year-old woman with chronic granulocytic leukemia and alveolar proteinosis required extracorporeal membrane oxygenator support for respiratory failure refractory to conventional therapy. During perfusion, each lung was lavaged with 10 L. of normal saline. The lavage led to marked clearing of the lungs and improvement in pulmonary function. Extracorporeal support was terminated successfully after 54 hours. The patient died 2 weeks later with bone marrow insufficiency and overwhelming sepsis. Pulmonary lavage is technically feasible during venovenous oxygenator bypass, and may be of value, since such lavage debrides alveoli as well as the bronchial tree. Because pulmonary lavage provides a possible means of improving pulmonary function, it seems worthy of consideration as an adjunct to membrane oxygenator support.

Measurement of intratracheal oxygen concentrations during face mask administration of oxygen: a modification for improved control

Direct measurement of the inspired tracheal oxygen concentration was made in patients breathing through standard aerosol face masks. Factors affecting the tracheal FIO2 were analyzed using both mechanical and mathematical models. When oxygen is delivered to the face mask at low flow rates, there is considerable patient variation in the measured tracheal FIO2. Delivery of oxygen at higher flow rates (15 litres per minute or greater), reduces such variation. Furthermore, turbulent air currents within and around the face mask reduce the measured FIO2 and contribute to fluctuations in the FIO2. This effect may be virtually eliminated by placing shields around the mask orifices as described. Using the shielded mask, it is possible to deliver the desired oxygen concentration to the patient more accurately and to maintain humidification of the delivered gases. Changes desired in inspired oxygen concentration are accomplished by changing the concentration of the incoming gas mixture, and not by merely changing the flow rate of oxygen delivered to the system. Using the shielded mask, it is possible to deliver an inspired oxygen concentration of 100 per cent. This is not true with most other commonly used face masks, and, therefore, caution should be used to avoid administration of unnecessary high inspired oxygen concentrations with this type of mask.

Fat embolism: a rational approach to treatment

Fat embolism following major trauma may be associated with a clinical syndrome with widespread pulmonary and systemic manifestations, the most serious being profound hypoxia with secondary atelectasis, pulmonary edema and pulmonary hypertension, and cerebral depression. Though the origin of the embolic fat is debated, there is evidence to support its origin from both the bone marrow and intravascular chylomicron coalescence.The clinical manifestations are largely explained by a prime assault upon the lung parenchyma and alteration in platelet characteristics.Early recognition and treatment of the condition is essential, adequate oxygenation being of prime importance. Steroids and heparin have been found to be of benefit.