PubMed Health⌕ Search

Biomedical subjects

R Proietti

Publications and source records attributed to R Proietti.

At least 19 recordsLinked to original sources
PubMed2003

Comparison of positive end-expiratory pressure with reverse Trendelenburg position in morbidly obese patients undergoing bariatric surgery: effects on hemodynamics and pulmonary gas exchange.

BACKGROUND: Anesthetized morbidly obese patients often exhibit impaired pulmonary gas exchanges, mostly because of a reduction in functional residual capacity. At present, several approaches are suggested to ventilate these patients. METHODS: The efficiency of positive end-expiratory pressure (PEEP) and reverse Trendelenburg position (RTP) were compared in order to improve oxygenation in 20 morbidly obese patients undergoing bariatric surgery. RESULTS: Both PEEP and RTP determined a significant decrease in alveolar-arterial oxygen difference and an increase in total respiratory compliance (Ctot). RTP resulted in lower airway pressures than PEEP with similar improvements in Ctot and oxygenation. Concerning hemodynamic parameters, cardiac output (CO) significantly decreased with both PEEP and RTP. CONCLUSIONS: RTP and PEEP can be considered adequate ventilatory settings for morbidly obese patients, without any significant difference with regard to gas exchange improvement. However, the decrease in CO may partially counteract the beneficial effects on oxygenation of these ventilatory settings.

Adult↗
PubMed2002

Effects of acid-base abnormalities on blood capacity of transporting CO(2): adverse effect of metabolic acidosis.

OBJECTIVE: To investigate the effects of some acid-base abnormalities on blood capacity of transporting CO(2). DESIGN: Prospective study. SETTING: General and Cardiosurgical ICUs of a University hospital. PATIENTS: Six groups of ten patients characterized by: metabolic alkalosis; respiratory alkalosis; absence of acid-base abnormalities; metabolic acidosis; uncompensated respiratory acidosis; and compensated respiratory acidosis. MEASUREMENTS AND RESULTS: The CO(2) dissociation curve, Haldane effect, and the ratio Ra-v between Ca-vCO(2) and Pa-vCO(2) were calculated from arterial and mixed-venous blood gas analyses. The CO(2) dissociation curve was shifted upwards by metabolic alkalosis and compensated respiratory acidosis and downwards by metabolic acidosis. The slope of the curve was unaffected, but CO(2) transport not due to Haldane effect was significantly lower in respiratory acidosis since the slope was less steep at higher PCO(2) values. In comparison with controls, patients affected by metabolic acidosis showed lower Haldane effect values (0.18+/-0.15 vs 0.59+/-0.26 ml of CO(2) per ml of arterial-mixed venous O(2) content difference; P <.05) and Ra-v values (0.43+/-0.10 vs 0.84+/-0.17 ml of CO(2) transported by 100 ml of blood per Torr of arterial-mixed venous PCO(2) gradient; P <.05). CONCLUSIONS: Our findings suggest that acid-base abnormalities, particularly metabolic acidosis, markedly affect blood capacity of transporting CO(2) and may worsen tissue hypercarbia associated with hypoperfusion. However, because of possible errors due to small measurements and the assumptions of the method, in the future definitive clarification will require the construction of original CO(2) dissociation curves for each acid-base abnormality.

Acidosis↗
PubMed2002

Sleep organization pattern as a prognostic marker at the subacute stage of post-traumatic coma.

OBJECTIVES: The aim of this study is to identify the predictive indexes for post-traumatic coma prognosis, which is important to better direct acute and subacute treatments and rehabilitation efforts. The pattern of sleep organization is a potential prognostic marker, but its role has not been established yet in the context of modern critical care. In the present study, we used a new protocol to evaluate the prognostic value of the different levels of sleep-wake organization recorded at the subacute stage of post-traumatic coma. METHODS: Twenty-four head-injured comatose patients were monitored with 24h polysomnographic recordings. The predictivity of the different levels of sleep-wake organization on polysomnography was compared with other possible prognostic indexes (i.e. neuroradiological findings, age and Glasgow Coma Scores (GCS)). Main outcome measures were survival and the degree of disability after recovery from coma. RESULTS: The presence of organized sleep patterns, but not GCS, was highly predictive of better outcome (odds ratio=10.78, P=0.01), even after correction for potentially confounding variables with multivariate analysis. CONCLUSIONS: Our study demonstrates that the sleep-wake organization pattern based on 24h polysomnographic recordings at the subacute stages of post-traumatic coma is a reliable prognostic marker, both for survival and for functional recovery.

Adolescent↗
PubMed2002

Effects of low-dose alfentanil administration on central respiratory drive and respiratory pattern in spontaneously breathing ASA 1 patients.

The aim of this study was to assess the short-term effects of the administration of low doses of alfentanil on respiratory drive and respiratory pattern. We studied 17 ASA I patients scheduled for minor surgery or endoscopic procedures. During spontaneous ventilation, Respiratory Rate, Tidal Volume, Total Respiratory Cycle, Inspiratory and Expiratory Time, Mean Inspiratory Flow, P0.1, S(a)O(2) and EtCO(2) were all measured. The inspired oxygen concentration was 21% and measurements were made at baseline, 5 min (T1), 10 min (T2) and 15 min (T3) following an intravenous bolus injection 10 microg.kg(-1) alfentanil. The administration of alfentanil produced a significant (p < 0.05) reduction in S(a)O(2), minute volume and P0.1. In ASA I spontaneously breathing patients, the pre-operative administration of low doses of alfentanil can initially reduce the respiratory centre activity leading to a reduction in minute volume and S(a)O(2). We therefore recommend careful monitoring of cardio-respiratory function in ASA I patients, following the administration of alfentanil.

Alfentanil↗
PubMed2002

Closed versus open suctioning techniques.

Airway suctioning is classically performed with the disconnection of the patient from the ventilator and the introduction of the suction catheter into the endotracheal tube. Alternatively, it can be accomplished with a closed suctioning system included in the ventilatory circuit, allowing to introduce the suction catheter into the airways without disconnecting the patient from the ventilator. The closed-suction system has some advantages compared to the conventional, open-suction technique. It can be helpful in limiting environmental, personnel and patient contamination and in preventing the loss of lung volume and the alveolar derecruitment associated with standard suctioning in the severely hypoxemic patients. However, the impact of the closed system on ventilator-associated pneumonia as well as its cost-effectiveness and the influence of such devices with ventilatory support remain to be assessed.

Humans↗
PubMed2001

Predictors of failure of noninvasive positive pressure ventilation in patients with acute hypoxemic respiratory failure: a multi-center study.

CONTEXT: In patients with hypoxemic acute respiratory failure (ARF), randomized studies have shown noninvasive positive pressure ventilation (NPPV) to be associated with lower rates of endotracheal intubation. In these patients, predictors of NPPV failure are not well characterized. OBJECTIVE: To investigate variables predictive of NPPV failure in patients with hypoxemic ARF. DESIGN: Prospective, multicenter cohort study. SETTING: Eight Intensive Care Units (ICU) in Europe and USA. PATIENTS: Of 5,847 patients admitted between October 1996 and December 1998, 2,770 met criteria for hypoxemic ARF. Of these, 2,416 were already intubated and 354 were eligible for the study. RESULTS: NPPV failed in 30% (108/354) of patients. The highest intubation rate was observed in patients with ARDS (51%) or community-acquired pneumonia (50%). The lowest intubation rate was observed in patients with cardiogenic pulmonary edema (10%) and pulmonary contusion (18%). Multivariate analysis identified age > 40 years (OR 1.72, 95% CI 0.92-3.23), a simplified acute physiologic score (SAPS II) > or = 35 (OR 1.81, 95% CI 1.07-3.06), the presence of ARDS or community-acquired pneumonia (OR 3.75, 95% CI 2.25-6.24), and a PaO2:FiO2 < or = 146 after 1 h of NPPV (OR 2.51, 95% CI 1.45-4.35) as factors independently associated with failure of NPPV. Patients requiring intubation had a longer duration of ICU stay ( P < 0.001), higher rates of ventilator-associated pneumonia and septic complications ( P < 0.001), and a higher ICU mortality ( P < 0.001). CONCLUSIONS: In hypoxemic ARF, NPPV can be successful in selected populations. When patients have a higher severity score, an older age, ARDS or pneumonia, or fail to improve after 1 h of treatment, the risk of failure is higher.

Acute Disease↗
PubMed2001

Volatile anesthesia in bariatric surgery.

BACKGROUND: Obesity causes anesthesiologists a broad variety of perioperative theoretical and practical problems. The aim of this study was to compare two protocols of anesthesia employing Isoflurane and Sevoflurane and evaluate the cardiorespiratory parameters, postoperative recovery and analgesia. METHODS: 90 patients underwent biliopancreatic diversion. 60 patients (group A) received Isoflurane and 30 patients (group B) were anesthetized with Sevoflurane. Intraoperative monitoring consisted of EKG, invasive arterial pressure, SpO2, EtCO2, Etanest, Spirometry, urinary output and TOF. Cardiorespiratory parameters and end tidal expiratory concentrations of volatile agents were collected during specific phases of surgery: 1) before induction of anesthesia, 2) after intubation, 3) after skin incision, 4) after positioning of costal retractors, 5) in the reverse Trendelenburg position, 6) end of surgery. During the postoperative period the Aldrete test was carried out to evaluate the recovery from anesthesia. VAS was administered for 6 hours after the end of surgery to set the quality of analgesia. RESULTS: No statistically significant differences in cardiorespiratory parameters were found between the two groups. Extubation time was significantly less in the Sevoflurane Group than in the Isoflurane (15 +/- 7 min vs 24 +/- 5 min, p < 0.05). The Sevoflurane Group showed an Aldrete score significantly higher than the Isoflurane (8.8 +/- 0.3 vs 8.1 +/- 0.4, p < 0.05). VAS values did not show statistical differences. CONCLUSION: The introduction of Sevoflurane, a volatile agent with rapid pharmacokinetic properties, seems to offer an interesting application in these patients.

Adult↗
PubMed2000

[Gas conditioning in artificial respiration].

The authors review the main systems used in the clinical setting to condition inspiratory gases during mechanical ventilation. More in details, the functional principles of hot water humidifiers and heat and moisture exchangers are described.

Conditioning, Psychological↗
PubMed2000

[Changes in acid-base equilibrium and CO2 output induced by bicarbonate infusion].

BACKGROUND: Bicarbonate therapy for metabolic acidosis can cause tissue hypercapnia. We tested the hypothesis that CO2 retention is initially confined to blood and that tissue hypercapnia is consequent to blood hypercapnia. METHODS DESIGN: prospective study. SETTING: general Intensive Care Unit in an University Hospital. PATIENTS: ten patients, aged 34-84, undergoing fixed mechanical ventilation for stroke, respiratory failure, polytrauma, or coma and presenting fairly stabilized circulatory condition were included in the study providing that definite exclusion criteria were absent. Sodium bicarbonate, 0.08, 0.17, and 0.25 mEq/kg, was infused in 5 minutes during stages A, B, and C. During each stage, before and after bicarbonate infusion, heart rate, arterial pressure, central venous pressure, and PetCO2 were registered and arterial and central venous haemogasanalysis were performed. CO2 output was measured during and after bicarbonate infusion and total CO2 output over basal values was calculated. RESULTS: Heart rate, arterial pressure, central venous pressure did not change in any stage, while PetCO2 increased in all. Following bicarbonate infusion, pH increased more in venous than in arterial blood and was significantly affected by the amount of bicarbonate infused. In arterial blood both PCO2 and total CO2 content (TCO2) increased. In venous blood PCO2 did not change while TCO2 increased so that arterial-venous rl CO2 difference was unaffected. CO2 output changed in no patient but two during stage A, and increased by 0.54 +/- 0.16 mL/kg during stage B and by 1.18 +/- 0.26 mL/kg during stage C so that 14.5 +/- 4.3 and 21.2 +/- 4.7% of given bicarbonate was released as CO2 through the lungs. CO2 output increased after a latency that was significantly shorter during stage C (145 +/- 51 sec) than during stage B (226 +/- 53 sec). CONCLUSIONS: Since arterial-venous TCO2 difference was unaffected and haemodynamic parameters were stable, the conclusion is drawn that CO2 and bicarbonate did not diffuse out of vascular compartment during this study. However CO2 and bicarbonate diffusion out of blood would have occurred if bicarbonate infusion had continued, because CO2 excess was released through the lungs after a latency and extended after the infusion. Consequently, tissue hypercapnia during bicarbonate infusion could probably be prevented by improving CO2 release through the lungs, i.e. by hyperventilating the patient.

Acid-Base Equilibrium↗
PubMed2000

[Home mechanical ventilation: the extra-hospital phase].

Home mechanical ventilation is the choice option, when there are no contraindications of medical or socio-economic order, in all cases of impossible complete weaning from ventilatory support. Easy to use, reliable and size limited positive pressure ventilators lead to a spread diffusion of this technique. In the patient/ventilator interface, tracheostomy is the golden choice for patient with great reduction in spontaneous ventilatory ability. For all other patients, perfectioning of non-invasive access (nasal and oral nasal mask) represent an effective progress. Major limitations in home ventilation are still, up to present, the lack of multidisciplinary structures able to give territorial assistance. Home ventilation therapy in the experience of the Policlinico Universtitario "La Sapienza", Rome is presented.

Home Care Services, Hospital-Based↗
PubMed1999

Changes in cerebral hemodynamics during laparoscopic cholecystectomy.

Laparoscopic surgery requires a series of procedures, including intraperitoneal CO2 insufflation, which can cause cardiovascular and hemogasanalytic modifications, potentially able to impair cerebral perfusion. The aim of this study was to evaluate changes in cerebral blood flow velocity during laparoscopic cholecystectomy. Eighteen patients undergoing laparoscopic cholecystectomy were studied. Middle cerebral artery blood flow velocity was monitored using transcranial Doppler ultrasonography. Electrical bioimpedance was employed to measure cardiac output, stroke volume and to calculate derived parameters. End-tidal CO2, mean arterial blood pressure, end expiratory anesthetic concentration and O2 saturation were monitored non-invasively. Cerebral artery blood flow velocity increased significantly after CO2 insufflation (p < 0.05) and remained stable. The highest values were reached after CO2 desufflation. A significant reduction in stroke volume and cardiac output (p < 0.05) associated with increased vascular systemic resistances (p < 0.001) was observed soon after CO2 insufflation. The decrease in cardiac output and the increase in vascular systemic resistances remained significant throughout abdominal insufflation. Heart rate and mean arterial pressure remained substantially unchanged with the exception of a significant decrease (p < 0.001) before CO2 insufflation. There was no significant change in end-tidal CO2 during abdominal insufflation. These findings suggest that the cerebrovascular system can undergo adaptive changes during all phases of laparoscopic surgery. However, the extent of cardio- and cerebrovascular variation indicates the need for careful preliminary evaluation of cerebral hemodynamics in patients with vascular disorders before laparoscopic surgery.

Adult↗
PubMed1999

Evaluation of the utility of serological tests in the diagnosis of candidemia.

BACKGROUND: It has been observed that the incidence and prevalence of candida infections in critically ill non-immunocompromised patients has increased. This study aims to evaluate the utility of the use of serological tests (double immunodiffusion and Cand-Tec Test) for the determination of candidemia. METHODS: A retrospective evaluation is made of 214 patients admitted to the Intensive Care Unit (ICU) of the Agostino Gemelli University Polyclinic during a period of 42 months. The double immunodiffusion technique was utilized for the determination of Candida antibodies. The Cand-Tec latex agglutination test was performed to evaluate the presence of Candida antigen. Four hundred and fifty-five antigen and antibody tests were performed. RESULTS: Thirty-six patients (16.8%) developed an invasive candidiasis. The sensitivity and specificity of antibody detection tests was 29 and 67 respectively; the positive predictive value was 15 and the negative predictive value was 82. The sensitivity and specificity of the antigen detection test ranged between 82 and 3 and between 8 and 98 respectively according to different cut-off titre; the positive predictive value was low (13-17%) and the negative predictive value decreased from 70 to 29. CONCLUSIONS: The utility of the use of serological tests in the diagnosis of candidemia is extremely limited. The gold standard for the determination of Candida sepsis remains the demonstration of candida in blood or in tissues.

Candidiasis↗
PubMed1999

[Target controlled infusion (TCI): applications of the "TCI visual" program in anesthesia and sedation with propofol].

BACKGROUND: Systems for Target Controlled Infusion accepting not only patient' data, like Diprifusor, but also a pharmacokinetic model have not been available in Italy in the last years. Therefore a program which controls a Pilot Anesthesia Vial pump and accepts any pharmacokinetic model was developed and applied to propofol infusion for anaesthesia and sedation. METHODS: Two versions of the Visual TCI program have been developed. The first, at intervals, supplies the anaesthetist with the values for the pump; the second directly interacts with the pump. The program also supplies the anaesthetist with the current amount of drug in each compartment and with the estimated awakening time. DESIGN: preliminary prospective study. SETTING: operatory theatre and Intensive Care Unit in a University Hospital. PATIENTS: 6 patients undergoing total intravenous anaesthesia with propofol and fentanyl for abdominal surgery; 6 patients undergoing sedation with propofol in an Intensive Care Unit (the first 4-hour period was taken into account). INTERVENTIONS: propofol infusion was regulated by the Visual TCI program. The first version was employed in three patients of each group and the second one in the others. Hypo- and hypertensive episodes (systolic pressure less than 80 mmHg or higher than basal value plus 25%) were recorded during anaesthesia and sedation. Propofol concentration was measured in plasma three times at defined intervals and per cent differences between measured and computer-calculated values (Predictive error, PE) were calculated. RESULTS: No hypo- or hypertensive episodes were recorded. PE was 27.4 +/- 17.9%. CONCLUSIONS: The program was easily employed, caused no inconvenience, and its use was associated with a remarkable cardiovascular stability. PE distribution was acceptable on the ground of the criteria reported in the literature. The program can be applied to drugs other than propofol, with both two and three compartment pharmacokinetic models and the anaesthetist can choose the most suitable model for the patient.

Adult↗