Prevention of the proliferation of oral pathogens due to prolonged mask use based on α-cyclodextrin and hydroxytyrosol mouthwash

OBJECTIVE

Face masks help contain the aerosol-mediated transmission of infectious viral particles released from individuals via cough and sneezes. However, the prolonged use of face masks has raised concerns regarding oral hygiene. Here, we present a mouthwash formulation based on α-cyclodextrin and hydroxytyrosol that can maintain healthy oral microbiota.

MATERIALS AND METHODS

We isolated and cultured Candida albicans, Staphylococcus aureus, and a mix of Streptococcus sp., Staphylococcus sp. and Neisseria sp. from oral and throat swabs. The microorganisms were cultured in a standard medium with or without the mouthwash. To evaluate the effect of the mouthwash on the oral microbiota, the DNA from the saliva of 3 volunteers that used the mouthwash was extracted. Then, the DNA was amplified using primer pairs specific for bacterial and fungal DNA. Twelve further volunteers were offered to use the mouthwash and a questionnaire was submitted to them to assess the possible beneficial effects of mouthwash on halitosis and other oral disturbances.

RESULTS

The bacteria and fungi cultured in media containing the mouthwash showed a growth reduction ranging from 20 to 80%. The PCR amplification of fungal and bacterial DNA extracted from volunteers that used the mouthwash showed a reduction of both bacteria and fungi. Volunteers that used the mouthwash reported a tendency towards a reduction of halitosis, gingival and mouth inflammation, and dry mouth.

CONCLUSIONS

The use of a mouthwash containing α-cyclodextrin and hydroxytyrosol is not aggressive against oral mucosa; it is safe and effective to reduce the bacterial and fungal load due to the continuous use of face masks.

The criterion of proportionality in the activation of Left Ventricular Assist Device implants: the method of "four boxes" to analyze the pre-implant phase

BACKGROUND

Life-saving technologies have completely changed the normal conception of medical treatments. Left Ventricular Assist Devices (LVAD) can prolong survival for patients who are not candidates for heart transplantation. In order to analyze the pre-implantation phase, which involves a shared-decision making process before activation of the device, attention should be paid to the criterion of "proportionality" in order to properly assess the risks and benefits of implantation.

AIM

The aim of our analysis is to provide an useful tool for the assessment of LVAD proportionality during the physicians' decision making.

METHODS

The method of the "four boxes", developed by Jonsen et al, was chosen to analyze the notion of proportionality and the other main ethical issues regarding LVAD activation in adult patients.

RESULTS

Medical issues are not the sole factors, which influence the choice of implantation by patients. Indeed, patient preferences, his/her quality of life, and contextual features should be taken into consideration when proposing LVADs: these factors are as important as clinical issues where outcomes are concerned.

CONCLUSIONS

In order to assess the proportionality of such a device, we present, discuss and examine, in the framework of the pre-implant phase, the content of each topic treated by the "four boxes method", that is, an essential tool for the assessment of the proportionality of the treatment for LVAD candidates.

Donation After Circulatory Death: When Withdrawing Life-Sustaining Treatments Is Ethically Acceptable

The possibility to determine death based on cardiocirculatory criteria in controlled cases, namely when there is a request to withhold treatment-or, more frequently, withdraw it-specifically recalls the recent Italian law on advance treatment directives and leaves the following question unanswered: Under what conditions is the patient's request legally and ethically acceptable? We present three ethical proportionality criteria for supporting physicians' decision-making facing patients' requests of treatment withdrawal, namely: 1. irreversible pathology with an ominous and worsening prognosis; 2. within an evaluation considering both clinical data and the patient's history; and 3. facing burdens that are no longer bearable. We finally argue that reflection over controlled donor may be a model for giving medicine the chance to responsibly deal with broader end-of-life issues.

Percutaneous gastric tube placement: Comparison of trans-abdominal and trans-oral approach in patients with chronic ascites

PURPOSE

The purpose of this study was to compare the trans-abdominal (TA) and trans-oral (TO) approaches for fluoroscopic-guided gastrostomy tube placement in patients with chronic ascites.

MATERIALS AND METHODS

A 10-year review of clinical imaging and medical records at a single institution identified 29 patients with chronic recurrent ascites who underwent gastrostomy (GT) or gastro-jejunostomy tube (GJT) placement. In 22 patients (18 women, 4 men) aged from 22 to 76 years of age (mean age, 57.7±13.1 years), a GT or GJT was placed with the TO approach, and in 7 (7 women) from 31 to 86 years of age (mean age, 63±16.8 years) with the TA approach.

RESULTS

Technical success was 100% in both groups with one (1/22; 5%) immediate complication in the TO group. Fluoroscopy time was significantly greater in the TO group (P=0.002). Leakage of ascites was significantly more frequent in the TA group (P=0.04). There was no significant difference in bleeding or inflammation (P=0.14 and P=0.43, respectively). The cumulative tract related complication rate was significantly greater in the TA group (P=0.03).

CONCLUSION

Fluoroscopy times and the overall incidence of tract-related complications, in particular leakage of ascites from the stoma, are more frequent in patients in chronic ascites who underwent TA gastrostomy tube placement compared to those who underwent TO placement.

The effect of chlorhexidine and gentian violet on the adherence of Candida spp. to urinary catheters

Urinary tract infection associated with catheters is the most common infection in the hospital environment. The adherence of microorganisms to the surface is a determining factor in colonization and infection. Antiseptics such as chlorhexidine and gentian violet have been shown to be effective against yeasts, as well as having low toxicity and being low-cost. The objective of the present study was to evaluate whether prior treatment of siliconized latex urinary catheters with antiseptics reduces the adherence of yeasts. Two reference strains of C. albicans (ATCC 645448 and ATCC 90028) and six strains isolated from catheter, two each of C. albicans, C. tropicalis, and C. parapsilosis, were used. An in vitro study of adherence was carried out with previously treated catheters, in separate experiments of 1 h and 24 h of incubation under continued shaking. The relative hydrophobicity of the cell surface of the yeasts before and after 1 h of exposure to chlorhexidine was determined. The results demonstrated that both treatments were effective in controlling the adherence of yeast to the catheter (P < 0.0001), and that the hydrophobicity of the eight strains significantly increased after contact with chlorhexidine (P < 0.0001). These results suggest that the antimicrobial activity of chlorhexidine and gentian violet reduces the adherence of the microorganisms to the catheter.

Interaction phenomena between oral implants and bone tissue in single and multiple implant frames under occlusal loads and misfit conditions: A numerical approach

An investigation is carried out on the effects induced in bone tissue surrounding oral implants placed in the premolar region of a mandible by using a numerical approach. In particular, a single implant and a multiple implant frame under loading are considered. The effects of accuracy in the coupling of the connecting bar and implants are evaluated. The mechanical response of the bone-oral implant system, depending on the different mechanical properties assumed for the peri-implant bone tissue during the evolutionary trend of osseointegration, is studied. A further task regard to the comparison of the mechanical state induced in the bone depending on the loading conditions considered. Effects of physiological occlusal loads are compared with ones given by framework defects arising from the specific manufacturing process, such as misfit between the implants and the connecting bar. The investigation offers the basis for an integrated clinical and biomechanical evaluation of the effects induced on peri-implant bone, depending on bone properties, implant system configuration, and the actions induced. Analyses performed show that stress states induced by the investigated type of misfit are comparable to those arising from the application of physiological loading conditions.

Effect of pepstatin A on the virulence factors of Candida albicans strains isolated from vaginal environment of patients in three different clinical conditions

The aspartate proteinase inhibitor pepstatin A was used to study a possible correlation among proteinase activity and other virulence factors of Candida albicans strains isolated from the vaginal environment of patients in three different clinical conditions: asympthomatic, vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC). The addition of 1.0 muM pepstatin A did not have any significant effect on hyphae formation, biofilm production and in the cell surface hydrofobicity of isolates in the three different clinical conditions. However, pepstatin A reduced the adherence of C. albicans to vaginal mucosa epithelial cells (53.1, 48.7 and 59.9%, respectively to isolates from asymptomatic, VVC and RVVC patients). This result suggests that the secreted aspartate proteinases (Saps) of this fungal pathogen may have auxiliary roles in cellular adhesion.

Evaluation of the Adherence ofCandidaSpecies to Urinary Catheters

Catheter-associated urinary tract infections (CAUTIs) are the most common kind of nosocomial infection. Recent years have seen a significant increase in numbers of infections caused by yeasts of the genus Candida. The adherence of a microorganism to the host surface is a decisive factor in the success of colonization and the pathogenesis of infection. The objective of this work was to evaluate the adherence of species of the genus Candida to urinary catheters. In vitro adherence to the sections of latex and silicon catheters of Candida albicans and Candida parapsilosis were studied. Adherence was measured by counting the number of adhering viable cells and the results were expressed as Colonies Forming Units per mL. The results demonstrated that the latex catheter facilitated adherence more than the silicon catheter (p < 0.01). The adherence of the C. albicans was significantly greater than C. parapsilosis on latex, but it was similar on silicon.

Adherence of Actinobacillus actinomycetemcomitans on oral epithelial cells

Actinobacillus actinomycetemcomitans is capable of colonizing mucosa and dental plaque and plays an important role in periodontal disease in young peoples and adult. Adherence mechanisms on epithelial cells, tooth or oral bacteria and gingival invasion probably are the initial steps in the pathogenesis of gingivitis or periodontitis. In this study, the adherence of A. actinomycetemcomitans on oral epithelial cells following subculturing were examined. The adherence on oral epithelial cells showed high in all the isolates values but with differences among them and at each time of subculturing. The adherence of A. actinomycetemcomitans FDC Y4 was stable in each of the subcultures. However, adhesion values of all the tested isolates were different except for strains #1, #38 and Y4, suggesting a heterogenicity within this microbial group. Morphologic variations were observed in extracellular structures of the A. actinomycetemcomitans tested. The adhesion process on oral epithelial cells of this organism can be influenced by subcultures, but additional studies are necessary to verify the influence of subculturing on adherence or other virulence factors.

[The PiCCO system with brachial-axillary artery access in hemodynamic monitoring during surgery of abdominal aortic aneurysm]

BACKGROUND

The haemodynamic monitor PiCCO System, based on transpulmonary arterial thermodilution, has been used with a brachial-axillary access instead of the femoral arterial access during abdominal aortic aneurysm surgical repair. Accuracy and limitations of pulse contour continuous cardiac output (PCCO) were evaluated on the basis of arterial thermodilution cardiac output. The patterns of cardiac index, preload, afterload and cardiac function parameters were also studied in the different phases of the surgical procedure.

METHODS

Twenty consecutive patients were studied. Mean differences (bias) between PCCO and arterial thermodilution cardiac output were calculated by the Bland-Altman test. Analysis of variance with multiple comparison test of haemodynamic variables in the different phases were performed. The correlation coefficients between cardiac index and the volumetric preload variables were also obtained.

RESULTS

Brachial artery catheterization was achieved without any major complication. Pulse contour continuous cardiac index (CI) and arterial thermodilution CI values showed overall mean differences (bias) of -0.04 Lámin-1. m-2 (SD 0.8) but after aortic cross-clamping and aortic unclamping they were 0.64 Lámin-1. m-2 (SD 0.57) e -0.57 Lámin-1. m-2 (SD 0.85), respectively (p<0.05). CI, global end-diastolic volume (GEDV) and intrathoracic blood volume (ITBVI) were significantly lower during aortic cross-clamping. CI was not correlated to central venous pressure (r=0.18) but instead, to GEDV (r=0.57) and ITBVI (r=0.65).

CONCLUSIONS

PiCCO System with brachial-axillary arterial access was suitable for haemodynamic monitoring of the abdominal aortic aneurysm surgical repair procedures. PCCO must be recalibrated with arterial thermodilution after aortic cross-clamping and unclamping to avoid an over-estimation and an under-estimation respectively. During aortic cross-clamping GEDV and ITBVI indicated a decreased preload. Other haemodynamic variables were less valuable but EVLWI showed an interesting steady increase during the whole procedure.

Lipid peroxidation, circulating cytokine and endothelin 1 levels in healthy volunteers undergoing hyperbaric oxygenation

BACKGROUND

The aim of the present study was to evaluate the effects of hyperbaric oxygenation on lipid peroxidation, on the release of circulating cytokines (TNFa, IL6, IL1b) and endothelin-1 (ET1).

METHODS

EXPERIMENTAL DESIGN

single arm, prospective study.

SETTING

ICU hyperbaric division of a University Hospital.

PATIENTS

fifteen healthy volunteers (10 male and 5 female, mean age 32+/-7 years) studied during hyperbaric oxygenation divided at random into two groups: group A (7 subjects) and group B (8 subjects).

INTERVENTIONS

Both groups were consecutively pressurized at 2 atmospheres (2 atm abs) and 2.8 atm abs, with a constant descending rate of 1 m/min; in accordance with the experimental design, group A breathed pure oxygen continuously through facial masks and group B breathed chamber air during pressurization.

MEASURES

Twenty millilitres of blood were drawn from all individuals at the following times: 1) basal, before HBO; 2) after 10 min at 2 atm abs; 3) after 10 min at 2.8 atm abs; 4) 30 min after the end of HBO. In all collected samples thiobarbituric reacting substances were evaluated, using the spectrophotometric technique, IL1 TNF and IL6 serum levels by ELISA and endothelin 1 plasma levels by radioimmunoassay.

RESULTS

In both groups, TBARS levels showed a twofold increase (p<0.05) in relation to the baseline, during and after hyperbaric oxygenation. Serum IL6 and IL1b values did not significantly change over the study in any of the volunteers. TNFa amounts significantly increased (p<0.05) during HBO, at 2 atm abs and 2.8 atm abs in both groups, with almost twofold increments. ET1 plasma values increased (p<0.05) in all volunteers during and after HBO: at 2 atm abs (range 7 to 24 pg/ml), 2.8 atm abs (range 7 to 19 pg/ml) and 30 min after (range 8 to 17 pg/ml) in relation to baseline (range 4 to 12 pg/ml). All the studied compounds had a similar trend in the two groups.

CONCLUSIONS

Hyperbaric oxygenation in healthy volunteers can induce not only lipid peroxidation, but also liberation of compounds such as TNFa and endothelins, no matter whether pure oxygen is breathed or not. These results suggest that the phenomenon behind this release might be leukocyte activation as induced by HBO. The possible role of ET1 in determining vasoconstriction occurring during HBO is also suggested.

[N2O-free sevoflurane anesthesia. Clinical evaluation]

BACKGROUND

The characteristics of sevoflurane make it able to be used without N2O avoiding its undesirable effects to this associates. The aim of the study is to evaluate the clinical characteristics of sevoflurane anesthesia "N2O free" in comparison to sevoflurane anesthesia with N2O.

METHODS

920 patient undergoing elective surgery in 12 centers were included in this study. All the patients were monitored with routine monitoring. The patients were randomized in two groups: group Air in which the anesthesia was maintained with sevoflurane in Air:O2; group N2O in which the anesthesia was maintained with sevoflurane in N2O:O2. Opioids were administered as necessary (changes of the heart rate and/or of the arterial pressure > 20% in comparison to the baseline values). For each patient we evaluated the consumption of opioids, the time from discontinuation of the sevoflurane and the extubation and full recovery, defined as presence of a complete cognitive function; the quality of awakening, the incidence of postoperative nausea and vomiting (PONV) and the quality of postoperative analgesia.

RESULTS

We didn't observe differences between the two groups. In conclusions, omitting N2O during sevoflurane anesthesia can be considered a safe technique, avoiding the acute and chronic side effects associated with the use of N2O, without modifying the intraop consumption of opioid, the recovery and the early postoperative incidence of nausea, vomiting and analgesia.

[Anesthesia in single and bilateral sequential lung transplantation. Lung Transplantation Group]

BACKGROUND

Anesthesia for lung transplantation: intraoperative complications and long term results.

METHODS

52 patients were scheduled for 16 single lung transplantations (SLT) (9 fibrosis and 7 emphysema) and 36 bilateral sequential lung transplantations (DLT) (4 bronchiectasis, 6 emphysema, 3 fibrosis, 22 cystic fibrosis and 1 pulmonary hypertension). Anesthesia was induced with propofol or midazolam, and fentanyl or alfentanil. As muscle relaxant vecuronium bromide was used. Anesthesia was maintained with isoflurane, fentanyl in boluses or sufentanil continuous infusion in O2 100%. Prostaglandin E1 (20-300 ng/kg/min), inhaled nitric oxide (10-40 ppm), dobutamine (5-15 mcg/kg/min), norepinephrine (0.05-3 mcg/kg/min) and ephedrine (5-10 mg per bolus) were used for hemodynamic management. In 2 patients inhaled areosolized prostacyclin were administered.

RESULTS

Mean pulmonary arterial pressure (mPA) and pulmonary vascular resistance (PVRI) increased after pulmonary artery clamping during first lung (mPA: 3347 nel DLT, 3643 nel SLT; PVRI; 375488 nel DLT, 377420 nel SLT) and second lung implantation (mPA: 3746; PVRI: 263553) and decreased after reperfusion of the first (mPA: 4737 nel DLT, 4329 nel SLT; PVRI: 488263 nel DLT, 420233 nel SLT) and the second lung (mPA: 4629; PVRI: 553260). Only in 9 cases (7 DLT and 2 SLT) C-P bypass was used.

CONCLUSIONS

With a strong drug support with pulmonary vasodilators, positive inotropic and systemic vasoconstrictor drugs, in most patients we transplanted C-P bypass can be avoided. Intraoperative deaths were not observed. Two years actuarial survival is 65% for DLT and 60% for SLT.

Noninvasive ventilation for treatment of acute respiratory failure in patients undergoing solid organ transplantation: a randomized trial

CONTEXT

Noninvasive ventilation (NIV) has been associated with lower rates of endotracheal intubation in populations of patients with acute respiratory failure.

OBJECTIVE

To compare NIV with standard treatment using supplemental oxygen administration to avoid endotracheal intubation in recipients of solid organ transplantation with acute hypoxemic respiratory failure.

DESIGN AND SETTING

Prospective randomized study conducted at a 14-bed, general intensive care unit of a university hospital.

PATIENTS

Of 238 patients who underwent solid organ transplantation from December 1995 to October 1997, 51 were treated for acute respiratory failure. Of these, 40 were eligible and 20 were randomized to each group.

INTERVENTION

Noninvasive ventilation vs standard treatment with supplemental oxygen administration.

MAIN OUTCOME MEASURES

The need for endotracheal intubation and mechanical ventilation at any time during the study, complications not present on admission, duration of ventilatory assistance, length of hospital stay, and intensive care unit mortality.

RESULTS

The 2 groups were similar at study entry. Within the first hour of treatment, 14 patients (70%) in the NIV group, and 5 patients (25%) in the standard treatment group improved their ratio of the PaO2 to the fraction of inspired oxygen (FIO2). Over time, a sustained improvement in PaO2 to FIO2 was noted in 12 patients (60%) in the NIV group, and in 5 patients (25%) randomized to standard treatment (P = .03). The use of NIV was associated with a significant reduction in the rate of endotracheal intubation (20% vs 70%; P = .002), rate of fatal complications (20% vs 50%; P = .05), length of stay in the intensive care unit by survivors (mean [SD] days, 5.5 [3] vs 9 [4]; P = .03), and intensive care unit mortality (20% vs 50%; P = .05). Hospital mortality did not differ.

CONCLUSIONS

These results indicate that transplantation programs should consider NIV in the treatment of selected recipients of transplantation with acute respiratory failure.

IL-8, IL-6 and ICAM-1 in serum of paediatric patients undergoing cardiopulmonary bypass with and without cardiocirculatory arrest

BACKGROUND

The aim of the present study was to evaluate the systemic inflammatory response to CPB in paediatric patients undergoing surgical correction of congenital heart diseases.

METHODS

EXPERIMENTAL DESIGN

comparative investigation.

SETTING

paediatric cardiology hospital

INTERVENTION

ICAM-1, IL-8, and IL-6 production were analysed before and during CPB, and after surgery in 9 paediatric patients, submitted to cardiocirculatory arrest (Group A); and in 11 without cardiocirculatory arrest (Group B).

MEASURES

ICAM-1, IL-8, and IL-6 production were analysed from arterial samples before and during CPB, and after surgery.

RESULTS

In group A vs group B a significant increase of IL-8 was detected during (297+/-250 vs 11+/-19 pg x ml(-1), p<0.001) and after (100+/-230 vs n.d. pg x ml(-1)) surgery and was correlated with the duration of operation (r=0.759; p=0.0001) and clamping time (r=0.738; p<0.05). After surgery in group A, IL-6 levels (35+/-43 pg x ml) were higher than those in group B (2+/-5 pg x ml), and a good correlation was observed between IL-6 and duration of aortic clamping (r=0.714; p=0.048), cardiac arrest, (r=0.714; p=0.048), and length of surgery (r=0.867; p=0.04).

CONCLUSIONS

In children who underwent CPB with cardiocirculatory arrest cytokine production seems related to duration of operation and amplified by ischemia-reperfusion phenomena.

[Hemodynamic changes during continuous infusion with dobutamine in candidates for lung transplantation. Lung Transplantation Group]

BACKGROUND

The aim of this study is to analyze the effects of dobutamine (DBT) on pulmonary and systemic hemodynamics and oxygenation in lung transplant candidates.

METHODS

Forty-five patients (21M, 24F) to be introduced in waiting list for lung transplantation were studied (14 pulmonary fibrosis, 15 COPD, and 16 cystic fibrosis). They were studied awake, while spontaneously breathing in two different phases: baseline--O2 100%; DBT phase--O2 100% after 10 minutes of DBT continuous infusion (10 mcg/Kg/min). Blood gas samples and hemodynamic data were collected during right heart catheterization. Data were statistically analyzed with Student's "t" test and values for p < 0.05 were considered as significant.

RESULTS

During DBT phase, a significant increase of cardiac output with a decreasing in systemic and pulmonary vascular resistance was observed. Since the fall in pulmonary vascular resistance (PVRI) was not proportional to the increase of cardiac output, mean pulmonary artery pressure and transpulmonary gradient increased. The prevalent role of vascular recruitment as mechanism in PVRI reduction during DBT is supported by the concomitant fall in PaO2/FiO2. This strongly suggests a worsening of regional Va/Qc due to an increased perfusion of poorly ventilated areas.

CONCLUSIONS

DBT reduces PVRI through a recruitment of vessels due to an increase of pulmonary flow. Dobutamine has a favorable hemodynamic effect in mild-to-moderate pulmonary hypertension in lung transplant candidates.

Noninvasive ventilation for the treatment of acute respiratory failure in patients with hematologic malignancies: a pilot study

OBJECTIVE

To evaluate treatment with noninvasive ventilation (NIV) by nasal mask as an alternative to endotracheal intubation and conventional mechanical ventilation in patients with hematologic malignancies complicated by acute respiratory failure to decrease the risk of hemorrhagic complications and increase clinical tolerance.

DESIGN

Prospective clinical study.

SETTING

Hematologic and general intensive care unit (ICU), University of Rome "La Sapienza".

PATIENTS

16 consecutive patients with acute respiratory failure complicating hematologic malignancies.

INTERVENTIONS

NIV was delivered via nasal mask by means of a BiPAP ventilator (Respironics, USA); we evaluated the effects on blood gases, respiratory rate, and hemodynamics along with tolerance, complications, and outcome.

MEASUREMENTS AND RESULTS

15 of the 16 patients showed a significant improvement in blood gases and respiratory rate within the first 24 h of treatment. Arterial oxygen tension (PaO2), PaO2/FIO2 (fractional inspired oxygen) ratio, and arterial oxygen saturation significantly improved after 1 h of treatment (43+/-10 vs 88+/-37 mmHg; 87+/-22 vs 175+/-64; 81+/-9 vs 95+/-4%, respectively) and continued to improve in the following 24 h (p < 0.01). Five patients died in the ICU following complications independent of the respiratory failure, while 11 were discharged from the ICU in stable condition after a mean stay of 4.3+/-2.4 days and were discharged in good condition from the hospital.

CONCLUSIONS

NIV by nasal mask proved to be feasible and appropriate for the treatment of respiratory failure in hematologic patients who were at high risk of intubation-related complications.

Do we know the costs of what we prescribe? A study on awareness of the cost of drugs and devices among ICU staff

OBJECTIVE

To evaluate the level of cost awareness of drugs and devices among intensive care unit (ICU) doctors with variable levels of experience (senior intensivists, junior intensivists, residents).

DESIGN

Interview-questionnaire.

SETTING

ICU of the University of Rome "La Sapienza".

PARTICIPANTS

60 ICU doctors (40 specialists in anaesthesia and intensive care, 20 residents).

MEASUREMENTS AND RESULTS

The estimated prices of drugs and devices were compared with the correct prices; responses within a range +/- 20% of the true price were arbitrarily considered correct; all the subgroups of doctors made inaccurate estimates of the prices, showing an absence of any impact of professional experience of cost awareness.

CONCLUSION

The doctors in the study showed a high level of inaccurate cost awareness of drugs and devices.

Anaesthesia for liver transplantation in cystic fibrosis patients

INTRODUCTION

Cystic fibrosis (CF) is a disease caused by an inherited genetic defect. While pulmonary and pancreatic abnormalities predominate the clinical spectrum, other organ involvement is common, including liver. The severity of liver disease does not appear to be related to the severity of exocrine pancreatic or lung function. We discuss anaesthesia in four CF patients undergoing liver transplantation.

METHODS

We studied haemodynamic and oxygenation modifications during anaesthesia in four patients affected by CF with end-stage liver disease and mild to moderate pulmonary abnormalities. The patients received pancreatic enzyme prior to transplantation and two had insulin-dependent diabetes mellitus. All patients were treated with broad-spectrum antibiotic therapy. After a waiting time ranging one week to three months, all patients were successfully transplanted. General anaesthesia was induced with fentanyl, thiopental and pancuronium, and maintained with isoflurane supplemented by fentanyl in O2:air. Haemodynamic and oxygenation evaluations were made during the main phases of the transplant. After the intubation and at the end of the procedure all patients received a broncho-alveolar toilet through fiberoptic bronchoscopy.

RESULTS

During anaesthesia for liver transplantation, PaO2 increased proportionally to the decreasing of Qs/Qt. In postoperative follow-up, Fev1 and FVC improved from preoperative time in all patients. In conclusion, even if cystic fibrosis is a multisystem disease, liver transplantation can be offered to CF patients with endstage liver disease and mild to moderate pulmonary function abnormalities. The four patients are still alive, enjoying good health. The improved respiratory function and quality of life of these children is remarkable.

Inhaled nitric oxide in patients with cystic fibrosis during preoperative evaluation and during anaesthesia for lung transplantation

INTRODUCTION

Inhaled nitric oxide (iNO) has been recently used as pulmonary vasodilator without any systemic effects because of a rapid inactivation by haemoglobin. We studied haemodynamic and oxygenation effects during iNO administration in cystic fibrotic patients during preoperative evaluation and during anaesthesia for lung transplantation.

METHODS

From March 1996 to November 1997, 35 patients received iNO (40 ppm) during preoperative evaluation in spontaneously breathing. 13 patients, who underwent double lung transplantation, received iNO (40 ppm) during the surgical procedures, after pulmonary artery clamping.

RESULTS

In the preoperative evaluation a significant decrease of mean pulmonary artery pressure, pulmonary vascular resistance index and intrapulmonary shunt, with an increase of PaO2/FiO2, were observed during iNO administration, compared to baseline in 100% O2. During lung transplantation a significant decrease in intrapulmonary shunt was noted. All the transplants were successfully performed without cardio-pulmonary bypass. In all procedures, after iNO administration, we observed no modification of systemic haemodynamics. In conclusion, our study confirms the pulmonary effects of iNO without any systemic effects in patients affected by cystic fibrosis during preoperative evaluation and during anaesthesia for lung transplantation.

A comparison of noninvasive positive-pressure ventilation and conventional mechanical ventilation in patients with acute respiratory failure

BACKGROUND AND METHODS

The role of noninvasive positive-pressure ventilation delivered through a face mask in patients with acute respiratory failure is uncertain. We conducted a prospective, randomized trial of noninvasive positive-pressure ventilation as compared with endotracheal intubation with conventional mechanical ventilation in 64 patients with hypoxemic acute respiratory failure who required mechanical ventilation.

RESULTS

Within the first hour of ventilation, 20 of 32 patients (62 percent) in the noninvasive-ventilation group and 15 of 32 (47 percent) in the conventional-ventilation group had an improved ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2:FiO2) (P=0.21). Ten patients in the noninvasive-ventilation group subsequently required endotracheal intubation. Seventeen patients in the conventional-ventilation group (53 percent) and 23 in the noninvasive-ventilation group (72 percent) survived their stay in the intensive care unit (odds ratio, 0.4; 95 percent confidence interval, 0.1 to 1.4; P=0.19); 16 patients in the conventional-ventilation group and 22 patients in the noninvasive-ventilation group were discharged from the hospital. More patients in the conventional-ventilation group had serious complications (66 percent vs. 38 percent, P=0.02) and had pneumonia or sinusitis related to the endotracheal tube (31 percent vs. 3 percent, P=0.003). Among the survivors, patients in the noninvasive-ventilation group had shorter periods of ventilation (P=0.006) and shorter stays in the intensive care unit (P=0.002).

CONCLUSIONS

In patients with acute respiratory failure, noninvasive ventilation was as effective as conventional ventilation in improving gas exchange and was associated with fewer serious complications and shorter stays in the intensive care unit.

Risk factors for acute renal failure in trauma patients

OBJECTIVE

To elucidate the risk factors for the development of acute renal failure (ARF) in severe trauma.

DESIGN

Prospective observational study.

SETTING

A general intensive care unit (ICU) of a university hospital.

PATIENTS

A cohort of 153 consecutive trauma patients admitted to the ICU over a period of 30 months.

RESULTS

Forty-eight (31%) patients developed ARF. They were older than the 105 patients without ARF (p = 0.002), had a higher Injury Severity Score (ISS) (p < 0.001), higher mortality (p < 0.001), a more compromised neurological condition (p = 0.007), and their arterial pressure at study entry was lower (p = 0.0015). In the univariate analysis, the risk of ARF increased by age, ISS > 17, the presence of hemoperitoneum, shock, hypotension, or bone fractures, rhabdomyolysis with creatine phosphokinase (CPK) > 10000 IU/l, presence of acute lung injury requiring mechanical ventilation, and Glasgow Coma Score < 10. Sepsis and use of nephrotoxic agents were not associated with an increased risk of ARF. In the logistic model, the need for mechanical ventilation with a positive end-expiratory pressure > 6 cm H2O, rhabdomyolysis with CPK > 10000 IU/l, and hemoperitoneum were the three conditions most strongly associated with ARF.

CONCLUSIONS

The identified risk factors for post-traumatic acute renal failure may help the provision of future strategies.

Comparative evaluation of the cardiorespiratory effects of assist control ventilation vs pressure support ventilation in patients following orthotopic liver transplantation

OBJECTIVE

1) To compare the haemodynamic tolerance of ACV and PSV in patients mechanically ventilated after orthotopic liver transplantation; 2) to compare patients comfort during ACV and PSV.

DESIGN

Prospective randomized cross-over study.

SETTING

General ICU of the University of Rome "La Sapienza".

PATIENTS

Eighteen patients admitted in ICU after orthotopic liver transplantation.

MEASUREMENT AND RESULTS

Haemodynamic, oxygen transport and blood gas data were compared during an ACV and PSV trial (30'). A statistically significant decrease of mean pulmonary and systemic arterial pressure, PCOP, LVSWI, occurred during the PSV trial. PaO2 and DO2I decreased during PSV, but were still in supranormal range; 16 out of 18 patients described PSV as more comfortable.

CONCLUSIONS

ACV and PSV provided a comparable haemodynamic tolerance in our patients, although during PSV the PaO2 was slightly decreased, probably due to decreased mean airway pressure (from 9.3 +/- 1.2 cmH2O during ACV to 6.6 +/- 1 cmH2O during PSV). PSV can be considered as a good alternative to the standard weaning techniques following orthotopic liver transplantation.

Efficacy of nefopam for the prevention and treatment of amphotericin B-induced shivering

BACKGROUND

Shivering is experienced by up to 70% of patients undergoing amphotericin B therapy. Treatment with meperidine hydrochloride, currently the most widely used medication for controlling amphotericin B-induced shivering, was compared with nefopam hydrochloride, which has been successfully used to treat post-operative shivering.

METHODS

Forty-five patients with cancer and systemic fungal infections randomly received nefopam hydrochloride, 0.3 mg/kg, meperidine hydrochloride, 0.7 mg/kg, or saline solution intravenously 15 minutes before the cessation of amphotericin B infusion (1 mg/kg for 45 minutes). If shivering persisted, patients in the control (saline solution) group received either nefopam hydrochloride, 0.3 mg/kg, or meperidine hydrochloride, 0.7 mg/kg.

RESULTS

Occurrence of shivering 15 minutes after the cessation of amphotericin B infusion was significantly less frequent in the nefopam (6.6%) and meperidine (40%) groups compared with the control group (66.6%). The incidence of shivering in the nefopam group with respect to the meperidine group was also significantly reduced. Moreover, nefopam administration to 5 persistently shivering patients in the control group definitively stopped the shivering in all of them (100%) in a mean (+/- SD) time of 29.1 +/- 4.8 seconds, while meperidine terminated shivering in 4 (80%) of 5 patients in a mean (+/- SD) time of 200.0 +/- 30.2 seconds. The adverse reactions that can be ascribed to nefopam or meperidine use were nausea and sedation, respectively, and may be considered negligible.

CONCLUSION

Nefopam seems to be more effective than meperidine in preventing and quickly suppressing amphotericin B-induced shivering.

Respiratory system mechanics in the early phase of acute respiratory failure due to severe kyphoscoliosis

OBJECTIVE

To evaluate respiratory mechanics in the early phase of decompensation in a group of seven patients with severe kyphoscoliosis (KS) (Cobb angle > 90 degrees) requiring mechanical ventilatory support.

DESIGN

Prospective clinical study with a control group.

SETTING

General intensive care unit at University of Rome "La Sapienza".

PATIENTS

Seven consecutive patients affected by severe KS in the early phase of acute decompensation and a control group of six ASA (American Society of Anesthesiology) 1 subjects who were mechanically ventilated during minor surgery.

MEASUREMENTS AND RESULTS

Respiratory mechanics were evaluated during constant flow-controlled mechanical ventilation at zero end-expiratory pressure with the end-inspiratory and end-expiratory occlusion technique. In five patients who showed increased ohmic resistance (RRSmin), we evaluated the possibility of reversing this increase with a charge dose of 6 mg/kg doxophylline i.v. In four KS patients, in whom a reliable esophageal pressure was confirmed by a positive occlusion test, we separated respiratory system data into lung and chest wall component. All KS patients showed reduced values of respiratory compliance (CRS) and increased respiratory resistance (RRS). The average basal values of CRS were 36 +/- 10 vs 58 +/- 8.5 cmH2O in control patients; RRSmax was 20 +/- 3.1 vs. 4.5 +/- 1.2 cmH2O/1 per s; RRSmin 6.2 +/- 1.2 vs. 2 +/- 0.5 cmH2O/1 per s: delta RRS 14 +/- 2.6 cmH2O vs 2.4 +/- 0.7 cmH2O/1 per s. All KS patients showed low values of intrinsic positive end-expiratory pressure (PEEPi) (1.8 +/- 1.5 cmH2O). Separation of lung and chest-wall mechanics, performed only in four patients, showed a reduction in both lung (66.7 +/- 7.2 ml/cmH2O) and chest wall values (84 +/- 8.2 ml/cmH2O), while both RmaxL and RmaxCW were increased (16.6 +/- 2 and 2.8 +/- 0.4 cmH2O/1 per s, respectively). Infusion of doxophylline did not significantly change respiratory mechanics when evaluated 15, 30, and 45 min after the infusion.

CONCLUSIONS

During acute decompensation, both lung and chest-wall compliance are severely reduced in KS patients: conversely, and, contrary to that in patients with chronic obstructive pulmonary disease, increases in airway resistance and PEEPi seem to play only a secondary role.

Exogenous reactive oxygen species deplete the isolated rat heart of antioxidants

The effects of reactive oxygen species (ROS) on myocardial antioxidants and on the activity of oxidative mitochondrial enzymes were investigated in the following groups of isolated, perfused rat hearts. I: After stabilization the hearts freeze clamped in liquid nitrogen (n = 7). II: Hearts frozen after stabilization and perfusion for 10 min with xanthine oxidase (XO) (25 U/l) and hypoxanthine (HX) (1 mM) as a ROS-producing system (n = 7). III: Like group II, but recovered for 30 min after perfusion with XO + HX (n = 9). IV: The hearts were perfused and freeze-clamped as in group III, but without XO + HX (n = 7). XO + HX reduced left ventricular developed pressure and coronary flow to approximately 50% of the baseline value. Myocardial content of hydrogen peroxide (H2O2) and malondialdehyde (MDA) increased at the end of XO + HX perfusion, indicating that generation of ROS and lipid peroxidation occurred. Levels of H2O2 and MDA normalized during recovery. Superoxide dismutase, reduced glutathione and alpha-tocopherol were all reduced after ROS-induced injury. ROS did not significantly influence the tissue content of coenzyme Q10 (neither total, oxidized, nor reduced), cytochrome c oxidase, and succinate cytochrome c reductase. The present findings indicate that the reduced contractile function was not correlated to reduced activity of the mitochondrial electron transport chain. ROS depleted the myocardium of antioxidants, leaving the heart more sensitive to the action of oxidative injury.

O2 consumption-O2 delivery relationship and arteriolar resistance in the forearm of critically ill patients measured by near infrared spectroscopy

Eight patients with severe sepsis, four with septic shock, and eight without sepsis were studied to investigate whether skeletal muscle influences the whole body O2 consumption (VO2)-O2 delivery relationship and hemodynamics. A forearm VO2-O2 delivery dependency was observed only in nonseptic patients, in whom no whole body VO2-O2 delivery dependency appeared. No forearm VO2-O2 delivery relationship was observed in septic and shock patients, in whom whole body VO2-O2 delivery dependency was found. In shock patients the lack of forearm VO2-O2 delivery dependency was associated with low forearm arteriolar resistance (FAR) even at a relatively low forearm blood flow (FBF). Neither a relationship between forearm VO2 and whole body VO2 nor between FAR and SVR was found in any groups of patients. Septic shock was associated with low FAR that was not affected by the FBF decrease, indicating that in this condition, hemodynamics could be influenced by skeletal muscle resistance.

Early and late onset bacteremia have different risk factors in trauma patients

OBJECTIVE

The aim of this study was to identify risk factors and to describe epidemiological patterns for early-(EOB) and late-onset bacteremias (LOB) after trauma.

DESIGN

A prospective study conducted on 141 consecutive trauma patients.

SETTING

A general intensive care unit (ICU) of a university hospital.

PATIENTS

All multiple trauma patients admitted to our general intensive care unit (ICU) from December 1990 to May 1992 were prospectively enrolled in the study. The following information was collected for each patient and recorded in a computer database: demography, severity of trauma according to the Abbreviated Injury Scale (AIS), severity of coma according to the Glasgow Coma Scale (GCS), presence of pneumothorax, pulmonary contusion, rib fractures, hemothorax, and abdominal trauma, use of mechanical ventilation, and placement of central venous catheters. Bacteremias were defined as EOB when onset occurred within 96 h after trauma, and as LOB when appearing after 96 h from trauma.

RESULTS

Thirty-seven patients developed bacteremia during their ICU stay (26%): 11 (29.7%) EOB and 26 (70.3%) LOB. Gram-positive cocci were isolated more frequently in EOB than in LOB (chi 2 = 4.1, P = 0.04). The risk of EOB was significantly increased by the presence of pulmonary contusion [relative risk (RR) 15.0; confidence interval (CI) 1.99-113.25], pneumonia before the onset of bacteremia (RR 3.56; CI 1.17-10.69), AIS score greater than 32 and an abdominal injury score greater than 9 (RR 3.11; CI 1.02-9.49), while intravascular catheters and mechanical ventilation did not represent risk factors for EOB. LOB had a very different pattern and their risk was significantly increased by exposure to intravascular catheters (RR 4.96; CI 1.23-19.94) and to mechanical ventilation lasting more than 7 days (RR 3.6; CI 1.6-8.1).

CONCLUSIONS

Scoring with the AIS of the abdominal and thoracic trauma at admission to the ICU appears a useful tool for identifying trauma patients at increased risk of EOB. A rigorous policy of catheter placement and maintenance as a means of reducing late bacteremias in trauma patients is essential.

Hemodynamic and metabolic effects of transjugular intrahepatic portosystemic shunt (TIPS) during anesthesia for orthotopic liver transplantation

Recently, the transjugular intrahepatic portosystemic shunt (TIPS) has been advocated as a safe bridge to orthotopic liver transplantation (OLT). We retrospectively studied 53 consecutive cirrhotic patients who underwent OLT: 27 patients with TIPS were compared to 26 controls. Hemodynamic and oxyphoretic data (Fick method) were collected during six phases of OLT. There were no significant differences in demographic data and Child-Pugh class, nor in surgical time and blood product requirements before the anhepatic phase between TIPS patients and controls. In the TIPS group, we observed a marked hyperdynamic profile with a lower systemic vascular resistance index, higher cardiac index, and depressed oxygen consumption before native liver removal. During the same period, the TIPS group developed a greater acidosis and was treated with a larger amount of NaHCO3. Following the anhepatic phase, no differences between the two groups were detected. All transplantations were successful, and no complications related to TIPS were observed. These results seem to be the consequence of a reduced liver function reserve with a direct hemodynamic effect due to the TIPS.

Antioxidant activity of silybin in vivo during long-term iron overload in rats

BACKGROUND & AIMS

Hepatic iron toxicity may be mediated by free radical species and lipid peroxidation of biological membranes. The antioxidant property of silybin, a main constituent of natural flavonoids, was investigated in vivo during experimental iron overload.

METHODS

Rats were fed a 2.5% carbonyl-iron diet and 100 mg.kg body wt-1.day-1 silybin for 4 months and were assayed for accumulation of hepatic lipid peroxidation by-products by immunocytochemistry, mitochondrial energy-dependent functions, and mitochondrial malondialdehyde content.

RESULTS

Iron overload caused a dramatic accumulation of malondialdehyde-protein adducts into iron-filled periportal hepatocytes that was decreased appreciably by silybin treatment. The same beneficial effect of silybin was found on the iron-induced accumulation of malondialdehyde in mitochondria. As to the liver functional efficiency, mitochondrial energy wasting and tissue adenosine triphosphate depletion induced by iron overload were successfully counteracted by silybin.

CONCLUSIONS

Oral administration of silybin protects against iron-induced hepatic toxicity in vivo. This effect seems to be caused by the prominent antioxidant activity of this compound.

Paralysis has no effect on chest wall and respiratory system mechanics of mechanically ventilated, sedated patients

OBJECTIVE

To evaluate the separate effects of sedation and paralysis on chest wall and respiratory system mechanics of mechanically ventilated, critically ill patients.

SETTING

ICU of the University "La Sapienza" Hospital, Rome.

PATIENTS AND PARTICIPANTS

13 critically ill patients were enrolled in this study. All were affected by disease involving both lungs and chest wall mechanics (ARDS in 4 patients, closed chest trauma without flail chest in 4 patients, cardiogenic pulmonary oedema with fluidic overload in 5 patients).

MEASUREMENTS AND RESULTS

Respiratory system and chest wall mechanics were evaluated during constant flow controlled mechanical ventilation in basal conditions (i.e. with the patients under apnoic sedation) and after paralysis with pancuronium bromide. In details, we simultaneously recorded airflow, tracheal pressure, esophageal pressure and tidal volume; with the end-inspiratory and end-expiratory airway occlusion technique we could evaluate respiratory system and chest wall elastance and resistances. Lung mechanics was evaluated by subtracting chest wall from respiratory system data. All data obtained in basal conditions (with the patients sedated with thiopental or propofol) and after muscle paralysis were compared using the Student's t test for paired data. The administration of pancuronium bromide to sedated patients induced a complete muscle paralysis without producing significant modification both to the viscoelastic and to the resistive parameters of chest wall and respiratory system.

CONCLUSIONS

This study demonstrates the lack of additive effects of muscle paralysis in mechanically ventilated, sedated patients. Also in view of the possible side effects of muscle paralysis, our results question the usefulness of generalized administration of neuromuscular blocking drugs in mechanically ventilated patients.

Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

In patients with acute exacerbations of chronic obstructive pulmonary disease, noninvasive ventilation may be used in an attempt to avoid endotracheal intubation and complications associated with mechanical ventilation.

METHODS

We conducted a prospective, randomized study comparing noninvasive pressure-support ventilation delivered through a face mask with standard treatment in patients admitted to five intensive care units over a 15-month period.

RESULTS

A total of 85 patients were recruited from a larger group of 275 patients with chronic obstructive pulmonary disease admitted to the intensive care units in the same period. A total of 42 were randomly assigned to standard therapy and 43 to noninvasive ventilation. The two groups had similar clinical characteristics on admission to the hospital. The use of noninvasive ventilation significantly reduced the need for endotracheal intubation (which was dictated by objective criteria): 11 of 43 patients (26 percent) in the noninvasive-ventilation group were intubated, as compared with 31 of 42 (74 percent) in the standard-treatment group (P < 0.001). In addition, the frequency of complications was significantly lower in the noninvasive-ventilation group (16 percent vs. 48 percent, P = 0.001), and the mean (+/- SD) hospital stay was significantly shorter for patients receiving noninvasive ventilation (23 +/- 17 days vs. 35 +/- 33 days, P = 0.005). The in-hospital mortality rate was also significantly reduced with noninvasive ventilation (4 of 43 patients, or 9 percent, in the noninvasive-ventilation group died in the hospital, as compared with 12 of 42, or 29 percent, in the standard-treatment group; P = 0.02).

CONCLUSIONS

In selected patients with acute exacerbations of chronic obstructive pulmonary disease, noninvasive ventilation can reduce the need for endotracheal intubation, the length of the hospital stay, and the in-hospital mortality rate.

[Anesthesia in experimental single-lung transplantation: hemodynamic and respiratory changes during prostaglandin E1 and nitroglycerin infusion]

INTRODUCTION

The haemodynamic and oxyforetic modifications induced by continuous infusion (c.i.) of Prostaglandin E1 (PGE1) and Nitroglycerin (NG) during experimental lung transplantation have been studied.

METHODS

Twenty lung transplants have been performed on pigs (Landrace). Haemodynamic monitoring consisted of ECG, femoral cannulation for arterial pressure and Swan Ganz catheter. Continuous infusion of drugs started during pneumonectomy. Data have been collected in phase 1: after the induction of anaesthesia; in phase 2: 30 min after the start of pulmonary vasodilation in one lung ventilation with left pulmonary artery clamped; in phase 3: 30 min after lung revascularization; in phase 4: at the end of the surgery. The animals have been divided in two groups. Group A consisted of 10 cases treated with 50 ng/kg/min in phase 2 and 25 ng/kg/min in phase 3 and 4 of PGE1; group B consisted of 10 cases treated with 1 ncg/kg/min in phase 2 and 0.5 ncg/kg/min in phase 3 and 4 of NG.

RESULTS

In phase 2 and 4 PA, RVSWI, PRVI increased in group B more than in group A (p < 0.05); in phase 3 PA, PAWP increased in group B more than in group A (p < 0.05).

DISCUSSION

In our experience PGE1 has shown to be a stronger pulmonary vasodilator than NG. PGE1 can be considered the drug of choice for pulmonary vasodilation in experimental single lung transplantation, even if more investigations are needed for reaching the real goal of this procedure.

Control of post anaesthetic shivering with nefopam hydrochloride in mildly hypothermic patients after neurosurgery

Postoperative shivering may be prevented by maintaining normothermia intraoperatively or it may be treated using specific drugs. The aim of this study was to compare the efficacy of nefopam hydrochloride (nefopam) to that of clonidine and meperidine in patients undergoing elective neurosurgical procedures. Three groups of patients were included in the study. Patients in group A (60) received i.v., at random, 20 mg of nefopam, 50 mg of meperidine or 150 micrograms of clonidine in the immediate postoperative period. The incidence of shivering and the time at which shivering ceased were noted, along with central temperature and main haemodynamic changes. Group B (20) received i.v., at random, either 10 mg of nefopam or saline before awakening from anaesthesia. The effects of nefopam on central temperature, oxygen consumption (Vo2), carbon dioxide production (VcO2), basal metabolic rate (BMR) and energy expenditure (EE) were investigated. Group C (10) received i.v. 20 mg of nefopam during surgery: cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP) and electroencephalogram (EEG) were monitored. In group A nefopam stopped shivering in 95% of patients when compared to meperidine and clonidine, which were effective in 32% and 40% of patients respectively. In group B, only 10% of patients receiving nefopam had postoperative shivering, Vo2, VcO2 and EE were significantly lower in patients treated with nefopam than those in the control group. No changes in CSFP, CPP or EEG were observed in group C. In conclusion, nefopam seems to be more effective than clonidine or meperidine in quickly suppressing shivering, without producing significant adverse reactions.

High IL-6 serum levels are associated with septic shock and mortality in septic patients with severe leukopenia due to hematological malignancies

The serum levels of immunoreactive interleukin-6 (IL-6) and tumor necrosis factor (TNF) were analyzed in 14 leukopenic patients with documented sepsis, at 60 min (T0), 24 h (T1), and one week (T3) after the onset of sepsis syndrome. Sera from 10 leukopenic patients without sepsis (controls) were also tested. All septic patients had high IL-6 levels at T0. These levels persisted only in the seven patients who died of septic shock, presenting a 30-fold increase (p<0.001) as compared to the survivors and the controls. At T3, 7 survivors had recovered from sepsis and showed low IL-6 serum levels. The TNF serum concentration always <30 pg/ml in both the subjects and in the controls. The C-reactive protein (CRP) and clinical parameters appeared to be less specifically associated with shock and mortality than IL-6.

A new device to remove obstruction from endotracheal tubes during mechanical ventilation in critically ill patients

OBJECTIVE

To evaluate the efficiency of a new device developed to remove obstructions from endotracheal tubes (ETT) in mechanically ventilated patients.

DESIGN

Open study in mechanically ventilated sedated and paralyzed ICU patients.

SETTING

General ICU and Laboratory of Respiratory Mechanics of the University of Rome "La Sapienza".

PATIENTS

8 consecutive unselected mechanically ventilated, critically ill patients in which a partial obstruction of ETT was suspected on the basis of an increase of the peak inspiratory pressure (> 20%) plus the difficult introduction of a standard suction catheter.

INTERVENTIONS

Obstructions to ETT were removed with an experimental "obstruction remover" (OR) MEASUREMENTS: "In vivo" ETT airflow resistance (0.25; 0.5; 0.75; 11/s) was evaluated before and after use of the OR; the work of breathing necessary to overcome ETT resistance (WOBett) was also evaluated before and after OR use.

RESULTS

The use of OR significantly reduced in all patients the ETT "in vivo" resistance (From 5.5 +/- 2.3 to 2.9 +/- 0.5 cmH2O/l/s at 0.25 l/s, p < 0.05; from 9 +/- 2.4 to 3.8 +/- 0.8 cmH2O/l/s at 0.5 l/s; from 12.2 +/- 3.5 to 5.7 +/- 1.2 cmH2O/l/s at 0.75 l/s; from 16.9 +/- 6 to 9.3 +/- 3.8 cmH2O/l/s at 1 l/s, p < 0.01 respectively). Also the WOBett was significantly reduced after use of the OR (from 0.66 +/- 0.19 to 0.34 +/- 0.08 J/l; p < 0.05).

CONCLUSION

this experimental device can be safely and successfully used to remove obstructions from the ETT lumen, without suspending mechanical ventilation, reducing the need for rapid ETT substitution in emergency and life-threatening situations.

Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation

Several modalities of ventilatory support have been proposed to gradually withdraw patients from mechanical ventilation, but their respective effects on the outcome of weaning from mechanical ventilation are not known. We conducted a randomized trial in three intensive care units in mechanically ventilated patients who met standard weaning criteria. Those who could not sustain 2 h of spontaneous breathing were randomly assigned to be weaned with T-piece trials, with synchronized intermittent mandatory ventilation (SIMV), or with pressure support ventilation (PSV). Specific criteria for performing tracheal extubation were defined for each modality. The number of patients who could not be separated from the ventilator at 21 d (i.e., who failed to wean) was compared between the groups. Patients in whom tracheal intubation was required in a 48-h period following extubation were also classified as failures. Among 456 mechanically ventilated patients who met weaning criteria, 109 entered into the study (35 with T piece, 43 with SIMV, and 31 with PSV). The three groups were comparable in terms of etiology of disease or characteristics at entry in the study. When all causes for weaning failure were considered, a lower number of failures was found with PSV than with the other two modes, with the difference just reaching the level of significance (23% for PSV, 43% for T piece, 42% for SIMV; p = 0.05). After excluding patients whose weaning was terminated for complications unrelated to the weaning process, the difference became highly significant (8% for PSV versus 33% and 39%, p < 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of hyperbarism on central respiratory drive and respiratory pattern in humans

The aim of our study was to evaluate the effects of increasing pressure (from 1 to 3 and 6 atm abs) on respiratory drive, respiratory pattern, and inspiratory impedance of the respiratory system. Seven healthy volunteers were studied during a dry compression to 6 atm abs in a hyperbaric multiplace chamber. We observed a significant increase in tidal volume, P0.1 (the pressure generated in the airway after 100 ms of inspiration against a closed inspiratory line), Ttot, and Ti, and a significant respiratory rate reduction with increasing pressure from 1 to 3 atm.abs; P0.1 also increased significantly when comparing 3 and 6 atm abs measurement with 1 atm abs. The P > 0.01 and P0.1/(VT/Ti) showed a significant progressive increase compared with 1 atm abs. In conclusion, the passage from 1 to 3 and 6 atm abs causes, in healthy subjects at rest, an increase in the central respiratory drive activity, evaluated with P0.1 measurement. The response to the respiration system is an increase in tidal volume and Ti with a decrease in respiratory rate.

Evaluation of respiratory system resistance in mechanically ventilated patients: the role of the endotracheal tube

OBJECTIVE

To investigate the role played by the endotracheal tube (ETT) in the correct evaluation of respiratory system mechanics with the end inflation occlusion method during constant flow controlled mechanical ventilation.

SETTING

General ICU, university of Rome "La Sapienza".

PATIENTS

12 consecutive patients undergoing controlled mechanical ventilation.

METHODS

We compared the values of minimal resistance of the respiratory system (i.e. airway resistance) (RRS min) obtained: i) subtracting the theoretical value of ETT resistance from the difference between P max and P1, measured on airway pressure tracings obtained from the distal end of the ETT; ii) directly measuring airway pressure 2 cm below the ETT, thus automatically excluding ETT resistance from the data. RESULTS. The values of RRS min obtained by measuring airway pressure below the ETT were significantly lower than those obtained by measuring airway pressure at the distal end of the ETT and subtracting the theoretical ETT resistance (4.5 +/- 2.8 versus 2.5 +/- 1.6 cm H2O/l/s, p < 0.01).

CONCLUSION

When precise measurements of ohmic resistances are required in mechanically ventilated patients, the measurements must be obtained from airways pressure data obtained at tracheal level. The "in vivo" positioning of ETT significantly increases the airflow resistance of the ETT.

Noninvasive measurement of forearm blood flow and oxygen consumption by near-infrared spectroscopy

We applied near-infrared spectroscopy (NIRS) for the simultaneous measurement of forearm blood flow (FBF) and oxygen consumption (VO2) in the human by inducing a 50-mmHg venous occlusion. Eleven healthy subjects were studied both at rest and after hand exercise during vascular occlusion. FBF was also measured by strain-gauge plethysmography. FBF measured by NIRS was 1.9 +/- 0.8 ml.100 ml-1.min-1 at rest and 8.2 +/- 2.9 ml.100 ml-1.min-1 after hand exercise. These values showed a correlation (r = 0.94) with those obtained by the plethysmography. VO2 values were 4.6 +/- 1.3 microM O2 x 100 ml-1.min-1 at rest and 24.9 +/- 11.2 microM O2 x 100 ml-1.min-1 after hand exercise. The scatter of the FBF and VO2 values showed a good correlation between the two variables (r = 0.93). The results demonstrate that NIRS provides the particular advantage of obtaining the contemporary evaluation of blood flow and VO2, allowing correlation of these two variables by a single maneuver without discomfort for the subject.

Risk factors for early onset pneumonia in trauma patients

STUDY OBJECTIVES

The aim of the study was to identify risk factors for early onset pneumonia (EOP) in trauma patients, in order to seek possible intervention strategies.

STUDY POPULATION

Participants included 124 consecutive trauma patients admitted to a general intensive care unit (ICU) of a university hospital from December 1990 to February 1992 inclusive.

DATA COLLECTION

The following data were prospectively collected for each patient: demographics, severity of trauma according to the abbreviated injury scale (AIS), severity of coma according to the Glasgow coma scale (GCS), presence of pneumothorax, pulmonary contusion, rib fractures, hemothorax, and mechanical ventilation. All patients were monitored daily during the ICU stay for the onset of pneumonia, sepsis syndrome, septic shock, and adult respiratory distress syndrome (ARDS). Criteria for the diagnosis of pneumonia were: core temperature of greater than 38.3 degrees C, a WBC count of 10,000 cells/mm3, purulent tracheobronchial secretions, a worsening of pulmonary gas exchange, and persistent pulmonary infiltrates. All patients with suspected pneumonia underwent quantitative bronchoalveolar lavage (BAL) as well as blood cultures; BAL cultures were considered positive when they showed bacterial growth greater than 1 x 10(5) colony-forming unit (cfu)/ml, or less than 10(5), but with the same microorganism isolated in blood cultures. Pneumonia occurring within the first 96 h after trauma was considered EOP.

DATA ANALYSIS

A stepwise logistic regression analysis was carried out in order to identify factors independently associated with an increased risk of EOP and late onset pneumonia (LOP).

RESULTS

Overall mortality was 43.5 percent: mortality increased by age and AIS score. Forty one patients (33.1 percent) developed pneumonia: 26 (63.4 percent) were EOP and 15 (36.6 percent) were LOP. In the univariate analysis, an age greater than 40 years, the presence of pulmonary contusion, AIS of more than 4 for thorax and of more than 9 for abdomen, and the absence of mechanical ventilation (MV) during the first 4 days of hospitalization or MV lasting less than 24 h were significantly associated with an increased risk of acquiring EOP. Logistic regression analysis showed that the strongest risk factor for EOP was a combined severe abdominal and thoracic trauma, which increased the risk of EOP by 11 times; an age of more than 40 years and MV of less than 24 h during the first 4 days of hospitalization were also independent risk factors for EOP. Factors associated with LOP were an AIS score of more than 4 for abdomen and a length of MV of more than 5 days.

CONCLUSION

In a trauma population, a combined severe abdominal and thoracic trauma represents a major risk factor for EOP. Mechanical ventilation administered during the first days after trauma seems to reduce the risk of EOP. As reported in previous studies, mechanical ventilatory support lasting more than 5 days is associated with an increased risk of LOP.

Effects of propofol on the human heart electrical system: a transesophageal pacing electrophysiologic study

Previous studies have shown that infusion of propofol has sometimes been associated with bradyarrhythmias. To evaluate the effects of propofol on the electrical system of the heart, we carried out an electrophysiologic study with transesophageal pacing on ten healthy subjects scheduled for minor elective maxillo-facial surgery. By means of atrial pacing conducted by a progressive increase in stimulation cycles, we determined, in awake patients and during propofol anesthesia (2.5 mg kg-1 for induction, followed by 100 micrograms kg-1 min-1 for maintenance), the correct sinus recovery time and the eventual appearance of Wenckebach atrio-ventricular block. We did not notice sinoatrial node depression or pathologic increase in the atrio-ventricular conduction.