Giorgio Berlot

Combined measurements of blood lactate concentrations and gastric intramucosal pH in patients with severe sepsis

OBJECTIVE To compare the prognostic value of blood lactate concentrations, gastric intramucosal pH, and their combination in patients with severe sepsis. DESIGN Prospective, noninterventional study. SETTING Medical/surgical intensive care unit of a university hospital. PATIENTS The study included 35 consecutive patients (44 to 82 yrs) with severe sepsis as defined by fever or hypothermia (rectal temperature > 38.3 degrees or < 35.5 degrees C), tachycardia (heart rate > 100 beats/min), tachypnea (respiratory rate > 20 breaths/min) or mechanical ventilation, abnormal white blood cell count (> 10 or < 6 x 10(3) cells/mm3), hypotension (systolic arterial pressure < 90 mm Hg), and evidence of organ dysfunction (oliguria or deterioration of mental status). INTERVENTIONS Arterial lactate concentration and intramucosal pH were measured at the time of study entry, and at 4 and 24 hrs later. Hemodynamic data and oxygen-derived variables were determined at the time of study entry and 24 hrs later. Arterial blood and balloon saline gases were also determined to obtain the pH gap (arterial pH-intramucosal pH) and the PCO2 gap (intramural PCO2-PaCO2). MEASUREMENTS AND MAIN RESULTS Of the 35 patients, 19 survived the intensive care unit stay. At the time of study admission, 23 (66%) patients had an increased lactate concentration (> 2 mEq/L) and 26 (74%) had a low intramucosal pH (< 7.32). Initially, there were no significant differences in blood lactate concentrations between nonsurvivors and survivors (3.2 +/- 1.5 vs. 2.8 +/- 2.3 mEq/L). Lactate concentrations remained high in nonsurvivors and progressively decreased in survivors (4 hrs: 3.3 +/- 1.1 mEq/L in nonsurvivors vs. 2.2 +/- 0.9 mEq/L in survivors [p < .01]; 24 hrs: 3.5 +/- 2.0 mEq/L in nonsurvivors vs. 1.9 +/- 1.1 mEq/L in survivors [p < .05]). Intramucosal pH was lower in the nonsurvivors than in the survivors initially (7.19 +/- 0.15 in nonsurvivors vs. 7.30 +/- 0.14 in survivors [p < .05]), at 4 hrs (7.18 +/- 0.17 in nonsurvivors vs. 7.29 +/- 0.13 in survivors [p = .06]), and at 24 hrs (7.19 +/- 0.31 in nonsurvivors vs. 7.30 +/- 0.17 in survivors [p < .05]). Of the 23 patients with initially high lactate concentrations, 12 (60%) of the 20 patients with low intramucosal pH died, as compared with one (33%) of the three patients with normal intramucosal pH (p = .052). Of the 14 patients with persistently high lactate concentrations at 24 hrs, all nine (100%) patients with low intramucosal pH, but only two (40%) of five patients with normal intramucosal pH died (p < .001). No significant relationship was found between lactate or intramucosal pH and oxygen-derived variables. Intramucosal pH correlated better with gastric intramural PCO2 (r2 = .58) than with arterial bicarbonate or base deficit/excess. Intramural PCO2 was a more specific predictor of mortality than intramucosal pH. When compared with patients with normal lactate concentrations, those patients with high lactate concentrations had a higher pH gap (0.22 +/- 0.22 vs. 0.07 +/- 0.13 [p < .01]) and PCO2 gap [21.0 +/- 33.9 vs. 1.8 +/- 9.8 torr [2.79 +/- 4.5 vs. 0.24 +/- 1.34 kPa]; p < .01). CONCLUSIONS Both lactate concentrations and intramucosal pH represent reliable prognostic indicators in severe sepsis, and their combination improves the prognostic assessment in these patients. Both variables are better prognostic indicators than oxygen-derived variables. Intramural PCO2 appears to be a more specific variable than intramucosal pH, which partially reflects systemic metabolic acidosis. Combined determinations of blood lactate concentrations and intramucosal pH or intramural PCO2 may help to predict outcome from severe sepsis.

Effect of positive expiratory pressure and type of tracheal cuff on the incidence of aspiration in mechanically ventilated patients in an intensive care unit.

Objective: To test the effects of positive expiratory pressure on the leakage of fluid around cuffs of different tracheal tubes, in mechanically ventilated patients and in a benchtop model. Design: Randomized clinical trial and experimental in vitro study. Setting: Intensive care unit of a university hospital. Patients: Forty patients recovering in the intensive care unit were ventilated in volume-controlled mode. Twenty patients were randomly intubated with Hi-Lo tubes (HL group), whereas the remaining 20 subjects were intubated with SealGuard tubes (SG group). Interventions: Immediately after intubation and cuff inflation with 30 cm H2O, Evans blue was applied onto the cephalic surface of the tracheal tube cuff. A 5-cm H2O positive expiratory pressure was used during the first 5 hrs of stay, and thereafter it was removed. Bronchoscopy verified whether the dye leaked around the cuff. The experiment lasted 12 hrs. Leakage was also tested in vitro with the same tracheal tubes with incremental level of positive expiratory pressure. Measurements and Main Results: At 1 hr, 5 hrs, and thereafter hourly until 12 hrs, bronchoscopy was used to test the presence of dye on the trachea caudal to the cuff. At the fifth hour, two patients of the HL group failed the test. One hour after positive expiratory pressure removal, all subjects in group HL exhibited a dyed lower trachea. On the other hand, one patient in group SG presented a leak at the eighth hour, and at the 12th hour three of them were still sealed. In vitro, the same level of positive expiratory pressure delayed the passage of dye around the cuff; after 30 mins positive expiratory pressure was removed, and in 10 mins all dye leaked only in the Hi-Lo tube. Conclusions: We found that 5 cm H2O positive expiratory pressure was effective in delaying the passage of fluid around the cuffs of tracheal tubes both in vivo and in vitro. The SealGuard tube proved to be more resistant to leakage than Hi-Lo.

High-Flow Nasal Interface Improves Oxygenation in Patients Undergoing Bronchoscopy

During bronchoscopy hypoxemia is commonly found and oxygen supply can be delivered by interfaces fed with high gas flows. Recently, the high-flow nasal cannula (HFNC) has been introduced for oxygen therapy in adults, but they have not been used so far during bronchoscopy in adults. Forty-five patients were randomly assigned to 3 groups receiving oxygen: 40 L/min through a Venturi mask (V40, N = 15), nasal cannula (N40, N = 15), and 60 L/min through a nasal cannula (N60, N = 15) during bronchoscopy. Gas exchange and circulatory variables were sampled before (FiO2 = 0.21), at the end of bronchoscopy (FiO2 = 0.5), and thereafter (V40, FiO2 = 0.35). In 8 healthy volunteers oxygen was randomly delivered according to V40, N40, and N60 settings, and airway pressure was measured. At the end of bronchoscopy, N60 presented higher PaO2, PaO2/FiO2, and SpO2 than V40 and N40 that did not differ between them. In the volunteers (N60) median airway pressure amounted to 3.6 cmH2O. Under a flow rate of 40 L/min both the Venturi mask and HFNC behaved similarly, but nasal cannula associated with a 60 L/min flow produced the better results, thus indicating its use in mild respiratory dysfunctions.

Simple thoracostomy in prehospital trauma management is safe and effective: a 2-year experience by helicopter emergency medical crews.

Objective To evaluate the effectiveness and potential complications of simple thoracostomy, as first described by Deakin, as a method for prehospital treatment of traumatic pneumothorax. Methods Prospective observational study of all severe trauma patients rescued by our Regional Helicopter Emergency Medical Service and treated with on-scene simple thoracostomy, over a period of 25 months, from June 1, 2002 to June 30, 2004. Results Fifty-five consecutive severely injured patients with suspected pneumothorax and an average Revised Trauma Score of 9.6±2.7 underwent field simple thoracostomy. Oxygen saturation significantly improved after the procedure (from 86.4±10.2% to 98.5%±4.7%, P<0.05). No difference exists in the severity of thoracic lesions between patients with systolic arterial pressure and oxygen saturation below and above or equal to 90. A pneumothorax or a haemopneumothorax was found in 91.5% of the cases and a haemothorax in 5.1%. No cases of major bleeding, lung laceration or pleural infection were recorded. No cases of recurrent tension pneumothorax were observed. Forty (72.7%) patients survived to hospital discharge. Conclusions Prehospital treatment of traumatic pneumothorax by simple thoracostomy without chest tube insertion is a safe and effective technique.

Influence of prehospital treatment on the outcome of patients with severe blunt traumatic brain injury: a single-centre study

Aim, patients, and methods To compare retrospectively the outcomes of patients with severe traumatic brain injury (Injury Severity Score, ISS total ≥15; the Abbreviated ISS-head, aISShead ≥9) admitted to our Intensive Care Unit by helicopter (helicopter emergency medical service, HEMS group = 89) with those transported by ambulance (GROUND group = 105) from January 2002 to December 2007. Results The groups were comparable for age, Glasgow Coma Scale, ISS total, and aISShead. The preadmission time of the HEMS group was significantly longer as compared with the GROUND group, but the interval from admission to definitive care was significantly shorter. In the prehospital phase, HEMS patients were more aggressively treated, as indicated by a significantly greater number of procedures performed (i.e. tracheal intubation and positioning of intravenous lines) and larger volumes of fluids infused. The overall mortality was lower in the HEMS than in the GROUND patients (21 vs. 25% respectively, P<0.05). The survival with or without only minor neurological disabilities was higher in the HEMS than in the GROUND group (54 vs. 44% respectively, P<0.05); among the survivors, the rate of severe neurological disabilities was lower in the HEMS than in the GROUND group (25 vs. 31%, P<0.05). Conclusion In our experience, aggressive early treatment of patients with severe traumatic brain injury was associated with a better outcome likely because of the prevention of secondary brain injury and a shorter interval elapsing from the trauma to definitive care despite more time spent on the scene by the intervening team.

Intravenous nicardipine in the treatment of postoperative arterial hypertension

BACKGROUND Calcium entry blockers are commonly used in the management of postoperative hypertension. The hemodynamic and blood gas effects of nicardipine, a dihydropyridine derivative available intravenously, were studied in patients after abdominal aortic surgery. METHODS Sixteen patients (66 +/- 8 years) who developed arterial hypertension (mean arterial pressure, > 90 mmHg) after abdominal aortic aneurysm reconstruction were studied. Fourteen patients had already been treated with a sodium nitroprusside infusion, the doses of which were maintained constant (mean dose: 1.42 +/- 1.04 micrograms/kg/min). Hemodynamic and blood gas data were collected at baseline, 15 minutes, and 45 minutes after a slow bolus administration of 3 to 5 mg of nicardipine. RESULTS After the nicardipine administration, mean arterial pressure decreased from 101 +/- 11 to 83 +/- 11 mmHg (p < 0.001), and the cardiac index acutely increased from 3.96 +/- 0.74 to 4.57 +/- 0.83 L/min/m2 (p < 0.05). Systemic vascular resistance significantly decreased. There were no significant changes in heart rate, stroke volume, cardiac filling pressures, pulmonary artery pressures, pulmonary vascular resistance, left ventricular stroke work, or right ventricular stroke work. One patient developed acute pulmonary edema, associated with a dramatic increase in cardiac filling pressures, and electrocardiographic signs of myocardial ischemia. Nicardipine administration was also associated with an acute reduction in Pao2 from 85.0 +/- 12.1 mmHg to 70.3 +/- 9.2 mmHg (p < 0.001), associated with an increase in venous admixture from 21.7% +/- 3.2% to 28.0% +/- 5.2% (p < 0.01). Oxygen delivery increased moderately and oxygen extraction decreased, but oxygen consumption was unchanged. CONCLUSION This study confirms the excellent efficacy of nicardipine in the management of postoperative hypertension, but underlines the risk of poor cardiac tolerance in patients after major surgery. Although oxygen delivery to the cells is usually well preserved, nicardipine can also significantly after blood oxygenation by increasing ventilation/perfusion mismatch.

High-frequency percussive ventilation improves perioperatively clinical evolution in pulmonary resection.

Objective:During thoracotomy, positive end-expiratory pressure is applied to the dependent lung and continuous positive airway pressure (CPAP) inflates the nondependent lung to avoid hypoxemia. These methods do not allow the removal of produced secretions. We hypothesized that high-frequency percussive ventilation (HFPV) can improve both conditions and reduce hospital length of stay in these patients. Design:Randomized prospective study. Setting:University Hospital. Patients:Fifty-three consecutive patients undergoing elective pulmonary partial resection were enrolled. Nine were excluded because of surgical reasons. Interventions:The nondependent lung was ventilated with HFPV in 22 patients and other 22 received CPAP. In both groups, the dependent lung was ventilated with continuous mechanical ventilation. Measurement and Main Results:Cardiocirculatory variables and blood gas analysis were measured during surgery. Postoperatively, all patients underwent chest physiotherapy, and Spo2, body temperature, the amount of sputum produced, and chest radiography were recorded. Before nondependent lung re-expansion, HFPV patients presented higher Pao2 than CPAP group (p = 0.020). The amount of secretions was higher in chronic obstructive pulmonary disease patients treated with HFPV than in those who received CPAP (199 and 64 mL, respectively, p = 0.028). HFPV increased by 5.28 times the chance of sputum production by chronic obstructive pulmonary disease patients (&khgr;2 = 46.66, p < 0.0001; odds ratio = 5.28). A patient treated with HFPV had a 3.14-fold larger chance of being discharged earlier than a CPAP-treated subject (likelihood ratio = 11.5, p = 0.0007). Conclusions:Under the present settings, HFPV improved oxygenation in one-lung ventilation during pulmonary resection. Postoperatively, it decreased the length of stay and increased the removal of secretions in comparison with CPAP.

Early short-term application of high-frequency percussive ventilation improves gas exchange in hypoxemic patients.

Background: Hypoxemia in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) patients represents a common finding in the intensive care unit (ICU) and frequently does not respond to standard ventilatory techniques. Objective: To study whether the early short-term application of high-frequency percussive ventilation (HFPV) can improve gas exchange in hypoxemic patients with ALI/ARDS or many other conditions in comparison to conventional ventilation (CV) using the same mean airway pressure (P_aw), representing the main determinant of oxygenation and hemodynamics, irrespective of the mode of ventilation. Methods: Thirty-five patients not responding to CV were studied. During the first 12 h after admission to the ICU the patients underwent CV. Thereafter HFPV was applied for 12 h with P_aw kept constant. They were then returned to CV. Gas exchange was measured at: 12 h after admission, every 4 h during the HFPV trial, 1 h after the end of HFPV, and 12 h after HFPV. Thirty-five matched patients ventilated with CV served as the control group (CTRL). Results: Pa<smlcap>o</smlcap>₂/Fi<smlcap>o</smlcap>₂ and the arterial alveolar ratio (a/A P<smlcap>o</smlcap>₂) increased during HFPV treatment and a Pa<smlcap>o</smlcap>₂/Fi<smlcap>o</smlcap>₂ steady state was reached during the last 12 h of CV, whereas both did not change in CTRL. Pa<smlcap>c</smlcap><smlcap>o</smlcap>₂ decreased during the first 4 h of HFPV, but thereafter it remained unaltered; Pa<smlcap>c</smlcap><smlcap>o</smlcap>₂ did not vary in CTRL. Respiratory system compliance increased after HFPV. Conclusions: HFPV improved gas exchange in patients who did not respond to conventional treatment. This improvement remained unaltered until 12 h after the end of HFPV.

Effects of the Volume of Processed Plasma on the Outcome, Arterial Pressure and Blood Procalcitonin Levels in Patients with Severe Sepsis and Septic Shock Treated with Coupled Plasma Filtration and Adsorption

Aims: To understand how coupled plasma filtration and adsorption (CPFA) could influence the time course of the advanced stages of sepsis, mean arterial pressure (MAP) and norepinephrine dosage. Methods: Patients with severe sepsis and septic shock with ≥2 organ failures not responding to volume resuscitation and vasopressor infusion were treated with CPFA within 8 h of admission to the intensive care unit. Results: Thirty-nine patients were treated (median age: 63 years, median SAPS II score: 45) and 28 survived advanced sepsis. In the latter, the median MAP increased and the norepinephrine dosage decreased significantly after CPFA, whereas in the nonsurvivors these values did not change significantly. The volume of treated plasma was significantly higher in survivors than nonsurvivors. Conclusion: These results suggest a possible existence of a dose-response effect for CPFA. Future studies are therefore recommended to evaluate the efficacy of this treatment and to determine its best timing and intensity.

Hemodynamics. PCO2 gradient

Mortality rate of elective infrarenal aortic aneurysm (AA) surgery has been reduced during the last 2 decades but not that of ruptured AA (RAA) operated on emergency (mortality rate about 45 %). However, autotransfusion has been introduced recently in the management of ruptured AA and appeared to reduce drastically mortality of RAA in a retrospective analysis of patients operated during the last 6 years. Forty-three patients were operated on for RAA from January 1986 to December 1991. Anaesthesia, surgical technics, or management of fluid replacement were identical for all patients except autotransfusion (AT) (Stat device, Dideco Lab.) which was used in some patients (n= 17) whenever it was possible. Number of death during surgery and at one month following surgery defined perioperative and postoperative mortality, respectively. Morbidity included postoperative renal or cardiac failures, or sepsis complications (pulmonary or septicemic infections). Stepwise regression analysis was used to delineate predicting factors of mortality and morbidity. Perioperative and postoperative mortality rates were 16.3% and 32.4%, respectively. Preoperative low blood pressure (systolic blood pressure less than 60 mmHg) was the best predicting factor of perioperative mortality (p=0.016) but AT use was the only predicting factor of postoperative mortality (p=0.002). Postoperative mortality of autotransfused patients was thus significantly lower than that of the other patients (12% vs 46%, respectively, p=0.018). Postoperative complications occured in 37 (82.9%) patients: 37 had renal insufficiency (creatinine clearance < 50 mVmin at day 1 after surgery) but only 2 patients required dialysis. Sepsis complications occured frequently (38.2%) mainly as pulmonary infection (35.3%), but no predictive factor of morbidity can be identified from stepwise regression analysis. In conclusion, perioperative autotransfusion may reduce mortality of RAA surgery and should be recommended.