Point of Care Ultrasound to Identify Diaphragmatic Dysfunction after Thoracic Surgery.

BACKGROUND: Postoperative diaphragmatic dysfunction after thoracic surgery is underestimated due to the lack of reproducible bedside diagnostic methods. We used point of care ultrasound to assess diaphragmatic function bedside in patients undergoing video-assisted thoracoscopic or thoracotomic lung resection. Our main hypothesis was that the thoracoscopic approach may be associated with lower incidence of postoperative diaphragm dysfunction as compared to thoracotomy. Furthermore, we assessed the association between postoperative diaphragmatic dysfunction and postoperative pulmonary complications. METHODS: This was a prospective observational cohort study. Two cohorts of patients were evaluated: those undergoing video-assisted thoracoscopic surgery versus those undergoing thoracotomy. Diaphragmatic dysfunction was defined as a diaphragmatic excursion less than 10 mm. The ultrasound evaluations were carried out before (preoperative) and after (i.e., 2 h and 24 h postoperatively) surgery. The occurrence of postoperative pulmonary complications was assessed up to 7 days after surgery. RESULTS: Among the 75 patients enrolled, the incidence of postoperative diaphragmatic dysfunction at 24 h was higher in the thoracotomy group as compared to video-assisted thoracoscopic surgery group (29 of 35, 83% vs. 22 of 40, 55%, respectively; odds ratio = 3.95 [95% CI, 1.5 to 10.3]; P = 0.005). Patients with diaphragmatic dysfunction on the first day after surgery had higher percentage of postoperative pulmonary complications (odds ratio = 5.5 [95% CI, 1.9 to 16.3]; P = 0.001). Radiologically assessed atelectasis was 46% (16 of 35) in the thoracotomy group versus 13% (5 of 40) in the video-assisted thoracoscopic surgery group (P = 0.040). Univariate logistic regression analysis indicated postoperative diaphragmatic dysfunction as a risk factor for postoperative pulmonary complications (odds ratio = 5.5 [95% CI, 1.9 to 16.3]; P = 0.002). CONCLUSIONS: Point of care ultrasound can be used to evaluate postoperative diaphragmatic function. On the first postoperative day, diaphragmatic dysfunction was less common after video-assisted than after the thoracotomic surgery and is associated with postoperative pulmonary complications.

Effect of positive end-expiratory pressure on pulmonary shunt and dynamic compliance during abdominal surgery.

BACKGROUND: General anaesthesia decreases pulmonary compliance and increases pulmonary shunt due to the development of atelectasis. The presence of capnoperitoneum during laparoscopic surgery may further decrease functional residual capacity, promoting an increased amount of atelectasis compared with laparotomy. The aim of this study was to evaluate the effects of different levels of positive end-expiratory pressure (PEEP) in both types of surgery and to investigate whether higher levels of PEEP should be used during laparoscopic surgery. METHODS: This prospective observational study included 52 patients undergoing either laparotomy or laparoscopic surgery. Three levels of PEEP were applied in random order: (1) zero (ZEEP), (2) 5 cmH2O and (3) 10 cmH2O. Pulmonary shunt and ventilation/perfusion mismatch were assessed by the automatic lung parameter estimator system. RESULTS: Pulmonary shunt was similar in both groups. However, in laparotomy, a PEEP of 5 cmH2O significantly decreased shunt when compared with ZEEP (12 vs 6%; P=0.001), with additional PEEP having no further effect. In laparoscopic surgery, a significant reduction in shunt (13 vs 6%; P=0.001) was obtained only at a PEEP of 10 cmH2O. Although laparoscopic surgery was associated with a lower pulmonary compliance, increasing levels of PEEP were able to ameliorate it in both groups. CONCLUSION: Both surgeries have similar negative effects on pulmonary shunt, while the presence of capnoperitoneum reduced only the pulmonary compliance. It appears that a more aggressive PEEP level is required to reduce shunt and to maximize compliance in case of laparoscopic surgery.

Transfusion of stored red blood cells in critically ill trauma patients: a retrospective study.

OBJECTIVE: The many published studies on the effects of the transfusion of stored red blood cells on clinical outcomes yielded discordant results. Therefore, we chose to study patients with severe trauma. The clinical outcomes considered included in-hospital mortality, the occurrence of sepsis, length of stay in intensive care unit and in hospital, and days of mechanical ventilation. PATIENTS AND METHODS: We selected all patients with traumatic injury, who received at least 2 red cell units in the first day of admission. Patients were divided into two groups: those who had received fresh red cells only (fresh group) and those who had received at least one "old" red cell unit (old group). The red cells were considered fresh if they had been stored <14 days. RESULTS: The fresh and old groups included 376 and 321 patients, respectively. Baseline demographic and clinical characteristics were comparable between the groups. However, old group received more red cell and plasma units during whole hospital stay (red cells: 11 ± 7 vs 6 ± 4, p < 0.001; plasma: 7 [0-9] vs 3 [0-6]). Among outcomes, only length of stay in intensive care unit (old vs fresh: 18 ± 9 vs 12 ± 8 days, p < 0.001) and in hospital (77 ± 35 vs 45 ± 30 days, p < 0.001) differed significantly between groups. The association remained statistically significant in a multivariate analysis including known confounding factors. CONCLUSIONS: Patients with major trauma transfused with old (≥14 days) red cells had a longer length of stay in intensive care unit and in hospital, without any difference in mortality, occurence of sepsis or days of mechanical ventilation.

A methodological approach for determination of maximal inspiratory pressure in patients undergoing invasive mechanical ventilation.

BACKGROUND: Maximal inspiratory pressure (MIP) can help to evaluate inspiratory muscle strength. However its determination in ventilated patients is cumbersome and needs special equipment. We hypothesized that MIP could be obtained by using the expiratory hold knob of the ventilator. The aim of this study was to verify whether: 1) the end expiratory occlusion technique can be used for MIP determination; and 2) if this technique provides different results compared to those obtained by the traditional method of MIP calculation. METHODS: We studied 23 consecutive patients undergoing mechanical ventilation for acute respiratory failure. The MIP was determined by two different methods, both based on occluding the airway for 20 seconds. This occlusion was obtained either by pressing the expiratory hold knob of the ventilator; or by detaching the patient from the ventilator circuit and using a noiseless pneumatic shutter placed on the inspiratory line of a two-way valve that allows expiration but prevents inspiration. RESULTS: The average values of MIP obtained by using either the hold knob of the ventilator or the noiseless pneumatic shutter were -46±14 cmH2O and -56±13 cmH2O, respectively. The linear regression analysis showed a significant correlation between MIPVent and MIPOcc (r2=0.95), although the Bland- Altman analysis revealed that they are not clinically comparable. CONCLUSION: MIP can be easily determined at the bedside by pressing the expiratory hold knob of ventilator. However, MIPVent and MIPOcc are different in terms of absolute value probably because they were determined at diverse lung volume.

Respiratory mechanics at different PEEP level during general anesthesia in the elderly: a pilot study.

BACKGROUND: General anesthesia could imply that the closing capacity exceed the functional residual capacity. This phenomenon, associated with a reduction of maximal expiratory flow, could lead to expiratory flow limitation (EFL). The aim of our study was to verify 1) a new method of determining EFL during anesthesia (PEEP test); 2) if anesthesia could be associated with the development of EFL; 3) if the use a small amount of PEEP is able to reverse the possible negative effects of low lung volume ventilation. METHODS: Fifty two patients scheduled for abdominal surgery were prospectively randomized in: 1) group ZEEP, ventilated at PEEP 0 H(2)O and 2) group PEEP ventilated at PEEP 5 cm H2O. The presence of EFL was determined by the negative expiratory pressure (NEP) test the day before surgery and by the PEEP test during surgery. Data of respiratory mechanics were calculated at the beginning and at the end of anesthesia. RESULTS: 1) The PEEP test allows the detection of EFL; 2) anesthesia was associated with EFL: 8 patients developed EFL after induction. At the end of surgery, 7 more patients became flow limited in the group ZEEP, while only 1 in the group PEEP. The group ZEEP exhibited a marked decrease of expiratory flow and a worsening of respiratory mechanics at the end of surgery. CONCLUSION: The PEEP test allowed to verify that EFL during anesthesia is a valuable phenomenon. The use of 5 cmH(2)O of PEEP was helpful to prevent the deterioration of lung mechanics that occurs during surgery.

LMA Supreme™ vs i-gel™--a comparison of insertion success in novices.

Two new supraglottic airway devices, the LMA Supreme™ (LMA) and the i-gel™, offer potential benefits when inserted by inexperienced operators. This study compared the insertion success rate and ventilation profile between the LMA Supreme and the i-gel when inserted by operators without previous airway management expertise. Following a short lecture and manikin training, airway novices were randomly allocated to insert either the LMA Supreme or the i-gel into 80 patients undergoing breast surgery. The primary outcome was first-time success rate, and secondary outcomes were overall success rate, insertion time, airway leak pressure, tidal volume during pressure controlled ventilation at 17 cmH(2)O, and adverse events. First-time insertion success rate was significantly higher for the LMA Supreme than the i-gel (30/39 (77%) vs 22/41 (54%); p = 0.029). Significantly more placement failures occurred with the i-gel (6 vs 0, p = 0.025). Mean (SD) leak pressure (29 (8) vs 23 (11) cmH(2)O, p = 0.007) and expired tidal volume (PCV 17 cmH(2)O) (785 (198) vs 654 (91), p = 0.001) were significantly greater with the LMA Supreme than with the i-gel, respectively. More patients complained of pharyngolaryngeal pain with the LMA Supreme than with the i-gel (17/39 (44%) vs 8/41 (20%); p = 0.053). We found better first time success rate, fewer failures, and a better seal with the LMA Supreme compared with the i-gel, indicating that the LMA Supreme may be preferable for emergency airway use by novices.

Randomized clinical trial of the effect of preoperative dexamethasone on nausea and vomiting after laparoscopic cholecystectomy.

BACKGROUND: Preoperative dexamethasone may reduce disabling symptoms such as pain, nausea and vomiting after laparoscopic cholecystectomy. METHODS: This was a randomized, double-blind, placebo-controlled trial. Between March and December 2004, 101 patients undergoing laparoscopic cholecystectomy were randomized to receive 8 mg dexamethasone (n = 49) or placebo (n = 52) intravenously before surgery. Six patients were excluded from the study. All patients received a standardized anaesthetic, surgical and multimodal analgesic treatment. The primary endpoints were: first, postoperative nausea, vomiting and pain; second, postoperative analgesic and antiemetic requirements. The pain scores (visual analogue and verbal response scales), the episodes of nausea (verbal response scale) and vomiting were recorded at 1, 3, 6 and 24 h, respectively, after the operation. Analgesic and antiemetic requirements were also recorded. RESULTS: No apparent drug side-effects were noted. Seven patients (14 per cent) in the treatment group reported nausea and vomiting compared with 24 (46 per cent) in the control group (P = 0.001). In the group of patients treated with dexamethasone, five (10 per cent) required antiemetics versus 23 (44 per cent) of those receiving placebo (P < 0.001). No difference in postoperative pain scores and analgesic requirements was detected between groups. CONCLUSION: Preoperative dexamethasone reduces postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy, with no side-effects, and may be recommended for routine use.

Tumour staging, morphology and p53 overexpression concur in predicting survival in hepatocellular carcinoma.

BACKGROUND/AIMS: The prognosis of hepatocellular carcinoma (HCC) on cirrhosis is hard to predict as it depends on tumour stage, underlying liver disease, type of treatment and, possibly, biological factors of the tumour itself. METHODS: We prospectively evaluated the survival of 91 consecutive patients with HCC on cirrhosis, diagnosed between January 1998 and December 1999. Clinical features and histological/biological aspects, including histotype, grade, p53 overexpression, cytoproliferation and apoptotic markers were analysed. RESULTS: Child-Pugh (P = 0.01), Okuda (P < 0.0001), Cancer of the Liver Italian Program (CLIP) staging (P < 0.0001) and type of treatment (P = 0.0001) were significantly related to survival. In the Cox model, CLIP staging was included as independent predictor of survival at step 1 (P < 0.0001) with Okuda at step 2 (P = 0.013). Amongst the biological factors, p53 overexpression and histotype were significantly related with survival (P = 0.0044 and 0.017 respectively). When clinical and biological variables were examined together in the Cox model, CLIP and Okuda were confirmed as being statistically related with survival (P < 0.0001 and =0.012) followed by histotype and p53 overexpression (P = 0.019 and 0.02). CONCLUSIONS: CLIP, Okuda, histotype and p53 overexpression are the strongest predictors of survival in this series of patients. These data confirm that staging of the tumour and underlying liver disease are strictly related to prognosis but support the concurrent role of clinical and biological factors in upgrading our capacity of predicting the fate of HCC patients.

The effect of volatile anesthetics on respiratory system resistance in patients with chronic obstructive pulmonary disease.

We examined the effect of isoflurane and sevoflurane on respiratory system resistance (Rmin,rs) in patients with chronic obstructive pulmonary disease (COPD). The diagnosis of COPD rests on the presence of airway obstruction, which is only partially reversible after bronchodilator treatment. Ninety-six consecutive patients undergoing thoracic surgery for peripheral lung cancer were enrolled. They were divided into two groups: preoperative forced expiratory volume in 1 s/forced vital capacity ratio <70% or >70%. Rmin,rs was measured after 5 and 10 min of maintenance anesthesia by using the constant flow/rapid occlusion method. Maintenance of anesthesia was randomized to thiopental 0.30 mg . kg(-1) . min(-1) or 1.1 minimum alveolar anesthetic concentration end-tidal isoflurane or sevoflurane. Eleven patients were excluded: two because anesthesia was erroneously induced with propofol and nine because of an incorrect tube position. Maintenance with thiopental failed to decrease Rmin,rs, whereas both volatile anesthetics were able to decrease Rmin,rs in patients with COPD. The percentage of patients who did not respond to volatile anesthetics was larger in those with COPD as well. In conclusion, we have demonstrated that isoflurane and sevoflurane produce bronchodilation in patients with COPD.

Spontaneous recanalization of internal carotid artery occlusion evaluated with color flow imaging and contrast arteriography.

AIM: In strokes of embolic origin a partial recanalization of the intracranial occluded vessel occurs with a high incidence (as high as 80%). In the literature, we find few cases of revascularization, detected with color flow imaging (CFI) or with arteriography (AGF), at carotid siphon or at the origin of an occluded internal carotid artery (ICA). Up to now there have been no reliable data on the incidence and clinical consequences of SR of an extracranial ICA occlusion. In this case-report we document 8 cases of SR of occluded ICA observed in the last 10 years in our Care Unit. METHODS: We observed 8 complete ICA occlusion at the origin, detected with CFI (8 of 8) and with AGF (7 of 8). All symptomatic patients and 2 of 5 asymptomatic patients underwent CT scan in the acute phase of stroke. All patients underwent CFI follow-up (every 6-12 monhts) to evaluate contralateral CCA and ICA and the presence of new focal neurological symptoms. All patients assumed BMT (antiplatelet or anticoagulant therapy). RESULTS: SR occurred in 6 patients between 24 and 96 months, in 1 patient within 8 months and 1 patient within 6 months from the diagnosis of ICA occlusion. Diagnosis of SR was based in all patients with CFI and in 4 patients confirmed with AGF. Five patients underwent CT scan that excluded haemorrhagic transformation of previous ischemic areas or new ischemic events (2 patients did CT scan only after SR). All patients underwent CFI follow-up in a 3-88 months period. There were no new focal neurological symptoms in 7 of 8 patients, 1 patient presented aspecific neurological symptoms. CONCLUSION: Diagnosing SR of occluded extracranical ICA seems to be more frequent than expected. SR is an event that has to be researched in follow-up of these patients; besides, it seems to have a relatively benign outcome with respect to the onset of new neurological symptoms.

Visceral artery aneurysms: a single center experience.

BACKGROUND: Splanchnic artery areurysm is a rare but clinically relevant disease, showing a high mortality rate in emergency surgery. Reports on splanchnic aneurysms are rare and often anecdotal. The aim of this study is to discuss data obtained from 16 patients in a single vascular surgery center. MATERIALS AND METHODS: Between January 1987 and December 2000, 16 patients underwent surgery for splanchnic artery aneurysms. In 13 patients the localization was single (in two associated with an infrarenal abdominal aortic aneurysm) and in 3 patients multiple. The arteries involved were: splenic (8), hepatic (4), celiac (3), superior mesenteric (3), ileocolic (2), and pancreatoduodenal (1). 13 patients were asymptomatic and 3 presentec with abdominal pain. All patients underwent CT scan, and abdominal aortic and selective visceral artery angiography. Before surgery, all patients underwent cerebral MR or cerebral CT scan. 13 patients underwent open vascular surgery; 3 patients (2 splenic and 1 hepatic) underwent endovascular procedure (angioembolization). Histological examination of the aneurysmal wall was obtained in 14 patients. Ultrasound examination was performed after 6 months, then yearly. 14 patients underwent abdominal CT scan during the long-term follow-up. RESULTS: Perioperative mortality was absent. 12 cases were classified as displastic, with minor or major secondary atherosclerotic changes, and in many cases severe calcications. 2 cases were classified as atherosclerotic. Cerebral MR did not show any cases of intracerebral displastric aneurismal disease. One patient was lost at follow-up after 9 years. One patient showed a recurrence at 6 years (superior mesenteric artery): the patient underwent a new surgical procedure and died 20 days after surgery for intestinal infarction. All abdominal follow-up CT scans show good results of the vascular reconstruction and escluded other new visceral or aortic aneurysms. CONCLUSIONS: Visceral artery aneurysms are an uncommon form of abdominal vascular disease showing a high postoperative mortality rate in emergencies. Surgery, and in selected cases, endovascular treatment, can successfully manage splanchnic artery aneurysms with few complications and low recurrence.

Early experiences with a porcine hepatocyte-based bioartificial liver in acute hepatic failure patients.

Orthotopic liver transplantation (OLT) is the only effective therapeutic modality in severe acute hepatic failure (AHF). The scarcity of organs for transplantation leads to an urgent necessity for temporary liver support treatments in AHF patients. A hepatocyte-based bioartificial liver (BAL) is under investigation with the main purpose to serve as bridging treatment until a liver becomes available for OLT, or to promote spontaneous liver regeneration. We developed a novel radial-flow bioreactor (RFB) for three-dimensional, high-density hepatocyte culture and an integrated pumping apparatus in which, after plasmapheresis, the patient's plasma is recirculated through the hepatocyte-filled RFB. Two hundred thirty grams of freshly isolated porcine hepatocytes were loaded into the RFB for clinical liver support treatment. The BAL system was used 8 times in supporting 7 AHF patients in grade III-IV coma, all waiting for an urgent OLT Three patients with no history of previous liver diseases were affected by fulminant hepatic failure (FHF) due to hepatitis B virus, 3 by primary non-function (PNF) of the transplanted liver, and one by AHF due to previous abdominal trauma and liver surgery. Six out of 7 patients underwent OLT following BAL treatment(s), which lasted 6-24 hours. All patients tolerated the procedures well, as shown by an improvement in the level of encephalopathy, a decrease in serum ammonia, transaminases and an amelioration of the prothrombin time, with full neurological recovery after OLT Our initial clinical experience confirms the safety of this BAL configuration and suggests its clinical efficacy as a temporary liver support system in AHF patients.

In-use light-duty gasoline vehicle particulate matter emissions on three driving cycles.

Twenty-four properly functioning and six high carbon monoxide emission light-duty gasoline vehicles were emission tested in Denver, CO, using the Federal Test Procedure (FTP), a hot start Unified Cycle (UC), and the REP05 driving cycles at 35 degrees F. All were 1990-1997 model year vehicles tested on both an oxygenated and a nonoxygenated fuel. PM10 emission rates for the properly functioning vehicles using oxygenated fuel averaged 6.1, 3.6, and 12.7 mg/mi for the FTP, UC, and REP05, respectively. The corresponding values for the high emitters were 52, 28, and 24 mg/mi. Use of oxygenated fuel significantly reduces PM10 on the FTP, with all the reduction occurring during the cold start. MOUDI impactor samples showed that 33 and 69% of the PM mass was smaller than 0.1 microm for the FTP and REP05 cycles, respectively, when collected under standard laboratory conditions. Particle number counts were much higher on the REP05 than the FTP. Counts were obtained using secondary dilution of samples drawn from the standard dilution tunnel. FTP PM10 was mostly carbonaceous material, 36% of which was classified as organic. For the REP05, as much as 20% of the PM10 was sulfate and associated water. Forty-five percent of the REP05 PM carbon emissions was classified as organic. Driving cycle had a significant impact on the distribution of the emitted polynuclear aromatic hydrocarbons.

Responsiveness to intravenous administration of salbutamol in chronic obstructive pulmonary disease patients with acute respiratory failure.

OBJECTIVE: In chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF), bronchodilating agents administered by inhalation have, in general, little effect on dynamic hyperinflation and concurrent static intrinsic positive end-expiratory pressure (PEEPi,st). Since in COPD the severely obstructed segments of the lung may not be reached by inhaled medication, we reasoned that drug efficiency may be enhanced by intravenous administration of the agent. DESIGN: Physiological study. SETTING: Two four-bed surgical-medical ICUs of a university hospital. PATIENTS: Fourteen COPD patients were studied within 36 h from the onset of ARF. MEASUREMENTS AND RESULTS: Static compliance (Cst,rs), minimal (Rmin,rs) and additional (DeltaRrs) resistance of the respiratory system, and PEEPi,st were measured before and after intravenous administration of salbutamol. All patients had limitation of air flow before and after salbutamol administration. On average, after salbutamol there was a small, though significant, decrease in Rmin,rs (-9%), DeltaRrs (-12%) and PEEPi,st (-8%). CONCLUSION: The changes in resistance and PEEPi,st after intravenous administration of salbutamol were too small to be of clinical significance.

Predictors of weaning outcome in chronic obstructive pulmonary disease patients.

Several threshold values for predicting weaning outcome from mechanical ventilation have been proposed. These values, however, have been obtained in nonhomogeneous patient populations. The aim of the present study was to determine the threshold values in chronic obstructive pulmonary disease (COPD) patients and compare them to those reported for nonhomogeneous patient populations. The initial weaning trial included 81 COPD patients. Fifty-three of them underwent a successful weaning trial, whereas 28 failed it. The latter were enrolled into the present investigation, and were restudied during a subsequent successful trial. The weaning indices used were those reported in the literature. The threshold values obtained were within 10% of those reported for a nonhomogeneous patients population only for tidal volume and effective compliance. The classification error was <20% for maximal inspiratory pressure (MIP), occluded inspiratory pressure swing (deltaPI)/MIP, rapid and shallow breathing (respiratory frequency/tidal volume), and compliance, rate, oxygenation, pressure index (CROP), whereas the area under the receiver operating characteristic curves was >0.9 only for deltaPI/MIP and CROP. In conclusion, the threshold values obtained in chronic obstructive pulmonary disease patients who failed the first weaning attempt differed from those previously reported. Although a gold standard weaning index is not available for chronic obstructive pulmonary disease patients, the occluded inspiratory pressure swing/ maximal inspiratory pressure and compliance, rate, oxygenation, pressure index may be candidates for such a role.

Respiratory mechanics during and after anaesthesia for major vascular surgery.

To evaluate the effects of major vascular surgery on respiratory mechanics, 11 patients undergoing general anaesthesia for abdominal aortic surgery were studied. Before aortic cross-clamping, chest wall elastance and resistance both increased (by 126% and 58%, respectively) when surgical retractors were placed. After aortic cross-clamping, lung elastance increased by 29%, accompanied by a decrease in cardiac index (22%) and an increase in pulmonary (17%) and systemic (15%) vascular resistance. After aortic unclamping, lung elastance decreased, although it remained higher than baseline values (by 12%). All cardiovascular variables returned to the values obtained before aortic cross-clamping.

[Respiratory circuits and infections of the airway]. / Circuiti dei respiratori e infezioni delle vie aeree.

OBJECTIVE: To study the effects of ventilator circuit changes on the rate of airway infections and to investigate the relationship between the microorganisms responsible for circuit colonization and those responsible for infection. DESIGN: Prospective study, carried out in two different periods, of one year duration each. SETTING: General Intensive Care Units (ICUs) in a University Hospital. PATIENTS: Seventy-eight patients, requiring mechanical ventilation (VAM) for more than 5 days, were enrolled. They were divided into two groups: in the first (group I, n. 36, 1st period) the ventilator circuit was changed every 5 days; in the second (group II, n. 42, 2nd period) every 10 days. INTERVENTION: Ventilator circuit change every 5 or 10 days. Daily culvert and filling of cascade humidifiers with sterile irrigation water. Daily replacement of mount catheter. MEASUREMENTS: Qualitative cultures of tracheobronchial aspirate and of fluid from the humidifying cascades and the expiratory tubing traps. RESULTS: The two groups were similar. Pneumonia and tracheobronchitis were found in the 25% and 11% of patients of group I and in 26% and 12% of those of group II respectively. The VAM duration was 26.5 +/- 15 days in patients who developed airway infection, and 12.9 +/- 11.6 days (p < 0.001) in patients who did not. The Gram+ organisms were predominant. An identical microorganism was found both in the tracheo-bronchial aspirate and in the circuit in 44 of 78 (56%) patients; no difference was found between infected (16 of 29) and non infected (28 of 49) patients. CONCLUSIONS: Changing the ventilator circuit every 10 days rather than every 5 days, does not increase the incidence of airway infections and result in considerable savings in the expenses of tubing and personnel time. The infection or colonization rates due to the same microorganisms are quite low and it seems not useful to make routine cultures of fluid from humidifying cascades and the expiratory tubing traps in order to characterize in time the microorganism that could be responsible of airway infections.

[Survival in intensive care of patients with chronic obstructive bronchopneumopathy and acute respiratory failure undergoing mechanical ventilation. Retrospective study]. / La sopravvivenza in Terapia Intensiva di pazienti con broncopneumopatia cronica ostruttiva e insufficienza respiratoria acuta sottoposti a ventilazione meccanica. Studio retrospettivo.

OBJECTIVE: To collect valuable informations for the evaluation of the patients' clinical evolution and to perform a cost-effectiveness analysis on the utilization of resources in the management of patients with chronic obstructive pulmonary disease (COPD) undergoing mechanical ventilation (MV) for acute respiratory failure (ARF). SETTING: General ICU. University Hospital. PATIENTS: 87 BPCO patients (mean age: 69.6 +/- 8.5) undergoing MV for ARF due to non surgical or traumatic events, for a total of 108 consecutive ICU admissions between January 1983 and December 1993. METHODS: Retrospective study in which the following data were collected: severity of the underlying chronic respiratory disease before the occurrence of ARF. For this aim patients have been divided into five classes (O-IV) according with ATS classification of dyspnea; causes of ARF; SAPS score; TISS score; OMEGA score; complications occurred in ICU; duration of MV; duration of stay in ICU; ICU and hospital outcome. RESULTS: In 48 cases (44.4%) clinical history was positive for a severe dyspnea (classes III-IV). Slight airway flogosis or infection were responsible of ARF in 78 cases; pneumonia was present in 24 cases while in 6 cases ARF was due to congestive heart failure. The study population was divided into two groups according with outcome. No statistically significant difference was observed in mean SAPS and TISS scores between the two groups (12.5 +/- 3 vs 13 +/- 4.8 and 18.4 +/- 2.3 vs 19 +/- 4.2). Mean OMEGA score was 155 +/- 11.7 (ES). With reference to ICU outcome the utilization rate or resources was 72.15% with a mean loss of resources of 43.2. Compli-cations were manly due to airway infection (16 cases) which was responsible in one case of the patient's death. Overall incidence of complications was relatively low and five of them led to patients' death in ICU. Mean duration of MV did not differ between the two groups (13.4 +/- 11.7 vs 14.3 +/- 11.7) but it was significantly longer in those patients whose clinical history was positive for severe dyspnea (classes III and IV) than in patients without this report (16.6 +/- 14.9 vs 10.9 +/- 6.9; p < 0.05). Mean stay in ICU did not differ significantly between survivors and non-survivors (21.4 +/- 18.6 vs 19.7 +/- 13). ICU mortality rate was 6.48% (7 patients) and hospital mortality rate was 20.3% (22 patients). CONCLUSIONS: Our results demonstrate that hospital outcome in COPD patients with ARF requiring mechanical ventilation is quite good. Prolonged mechanical ventilation and--severity of underlying chronic respiratory disease do not affect significatively the prognosis. The high costs of the treatment of these patients are counterbalanced by a good efficiency of utilization of resources and appreciable clinical results.