Feasibility of monomodal analgesia with IV alfentanil during burn dressing changes at bedside (in spontaneously breathing non-intubated patients).

INTRODUCTION: The severe pain related to repeated burn dressing changes at bedside is often difficult to manage. However these dressings can be performed at bedside on spontaneously breathing non-intubated patients using powerful intravenous opioids with a quick onset and a short duration of action such as alfentanil. The purpose of this study is to demonstrate the efficacy and safety of the protocol which is used in our burn unit for pain control during burn dressing changes. PATIENTS AND METHODS: Cohort study began after favorable opinion from local ethic committee has been collected. Patient's informed consent was collected. No fasting was required. Vital signs for patients were continuously monitored (non-invasive blood pressure, ECG monitoring, cutaneous oxygen saturation, respiratory rate) all over the process. Boluses of 500 (±250) mcg IV alfentanil were administered. A continuous infusion was added in case of insufficient analgesia. Adverse reactions were collected and pain intensity was measured throughout the dressing using a ten step verbal rating scale (VRS) ranging from 0 (no pain) to 10 (worst pain conceivable). RESULTS: 100 dressings (35 patients) were analyzed. Median age was 45 years and median burned area 10%. We observed 3 blood pressure drops, 5 oxygen desaturations (treated with stimulation without the necessity of ventilatory support) and one episode of nausea. Most of the patients (87%) were totally conscious during the dressing and 13% were awakened by verbal stimulation. Median total dose of alfentanil used was 2000µg for a median duration of 35min. Pain scores during the procedure were low or moderate (VRS mean=2.0 and maximal VRS=5). Median satisfaction collected 2h after the dressing was 10 on a ten step scale. CONCLUSION: Pain control with intravenous alfentanil alone is efficient and appears safe for most burn bedside repeated dressings in hospitalized patients. It achieves satisfactory analgesia during and after the procedure. It is now our standard analgesic method to provide repeated bedside dressings changes for burned patients.

Working time and workload of nurses: the experience of a burn center in a high income country.

We conducted a one-month study of the working time and workload of nurses in a 15 beds burn center (including 8 intensive care beds). Nurses' tasks were categorized according to their nature (medical care, local treatments, post anesthetic monitoring, administrative time related to health care, administrative time unrelated to health care, cleaning, rest). The time taken to complete a given task was measured for each task. The time devoted to walk and unavailable for patients care was also measured. Our study revealed that work distribution was far from optimal since administrative tasks occupy more than 30% of workload. This represents inefficiency and the literature shows that when time is saved from administrative work it is reinvested in health care. One third of the administrative tasks are unrelated to care and thus could be performed by non-specialized clerks. The other two third of the administrative workload are closely linked to care. An answer to reduce administrative time lost to care activities is the implementation of dedicated ICU software which carries several other advantages such as reducing the use of paper, improving the safety of prescriptions, automating repetitive and unrewarding tasks and saving physician time. This expensive solution can be quickly repaid through costs containment due to the time saved. A significant part of the working time is spent walking but reducing the ambulatory time may be considered only through structural improvements.

Viscoelastic properties of lungs and thoracic wall of anesthetized mechanically ventilated piglets.

OBJECTIVE: To investigate the viscoelastic properties of lungs and thoracic wall in piglets. STUDY DESIGN: Prospective experimental study. ANIMALS: Six piglets weighting 30 kg. METHODS: Animals were tracheotomized, anesthetized and mechanically ventilated under controlled conditions. After control measurements of the mechanical properties of the lung of the pigs had been taken, acute lung injury (ALI) was induced by saline lavage. Lung and thoracic wall tissue resistance (DeltaR), which reflects viscoelastic properties and/or time constant inequalities, were determined by using a rapid airway occlusion technique during constant flow inflation (V), at constant tidal volume. was varied from 0.1-0.2 to 1.2 L second(-1) on a single breath. Multiple data sets of DeltaR of lung (DeltaR(L)) and thoracic wall (DeltaR(w)) to inspiratory time (T(I) = V(T)/V) were fitted to a model whose prediction equation was DeltaR = R(2)[1 -exp(-T(I)/tau(2))], where R(2) and tau(2) are the 'viscoelastic' resistance and time constant, respectively. Subscripts (L) and (W) are used to represent lung and thoracic wall, respectively (R(2L), R(2W), tau(2L), tau(2W)). Two more sets of physiological measurements were then taken--the first under zero end-expiratory pressure (ZEEP) and the second under a positive end-expiratory pressure (PEEP) of 10 cmH(2)O. RESULTS: Data of DeltaR adequately fitted to the prediction equation in all instances. In control, R(2,L) was 15.3 (10.7-22.6) cmH(2)O L(-1) second(-1) (median, interquartile range), tau(2,L) 3.3 (1.9-5.5) seconds, R(2,w) 6.5 (2.2-10.3) cmH(2)O L(-1) second(-1) and tau(2,w) 2.9 (1.1-4.3) seconds. In ALI, R(2,L) significantly increased to 129.6 (105.9-171.3) cmH(2)O L(-1) second(-1) on ZEEP but not significantly decreased to 48.9 (17.8-109.6) cmH(2)O L(-1) second(-1) with PEEP. The corresponding values of tau(2,L) were 7.1 (5.1-11.6) and 4.4 (3.1-5.5) seconds. The values pertaining to thoracic wall did not change significantly among conditions. CONCLUSIONS AND CLINICAL RELEVANCE: Viscoelastic properties of the lung and thoracic wall in piglets can be described by a viscoelastic model. Values of parameters of this model were markedly increased in ALI and decreased with PEEP.

Assessment of airway closure from deflation lung volume-pressure curve: sigmoidal equation revisited.

OBJECTIVE: To assess a sigmoidal equation for describing airway closure. DESIGN: Experimental study. SETTING: University laboratory. PARTICIPANTS: Eight piglets mechanically ventilated on zero end-expiratory pressure (ZEEP). INTERVENTIONS: Control and lung saline lavage. MEASUREMENTS AND RESULTS: Lungs were inflated up to transpulmonary pressure of 30 cmH(2)O at constant flow (0.12l s(-1)) then deflated at the same flow rate up to the point at which oesophageal pressure was constant, which was assumed to represent complete airway closure. The deflation volume-transpulmonary pressure curve was fitted to: (1) a sigmoidal equation focusing on inflexion point and pressure at maximal compliance increase and (2) an exponential equation above an inflexion point determined by eyeballing. Data deviate from the exponential equation at the point of airway closure onset. The zero-volume intercept was determined. Complete airway closure was reached at -8.3+/-3.5cmH(2)O in control conditions and at -1.3+/-3.7 cmH(2)O after lavage (p < 0.05). Between control and lavage, onset of airway closure was 3.0+/-1.9 vs. 6.0+/-2.8 cmH(2)O (p <0.05), inflexion point 3.2+/-1.8 vs. 7.7+/-2.6 cmH(2)O (p <0.001), pressure at maximal compliance increase -1.9+/-0.7 vs. -0.03+/-2.1cmH(2)O (p <0.05) and zero-volume intercept -1.5+/-1.4 vs. 0.3+/-2.3cmH(2)O (p <0.05). CONCLUSIONS: During mechanical ventilation airways stay open and close around ZEEP in control but are closed above ZEEP after lavage. Inflexion point might reflect onset of airways closure in control. Pressure at maximal compliance increase was not a marker of complete airways closure. In control and lavage, pressure at maximal compliance increase and zero-volume intercept were reasonably equivalent.

Effects of inhaled fenoterol and positive end-expiratory pressure on the respiratory mechanics of patients with chronic obstructive pulmonary disease.

BACKGROUND: During acute ventilatory failure in patients with chronic obstructive pulmonary disease (COPD), applying external positive end-expiratory pressure (PEEPe) will reopen small airways and, thus, may enhance peripheral deposition as well as the physiological effects of inhaled beta-2 agonists. OBJECTIVE: To investigate the efficacy of inhaled fenoterol applied by zero end-expiratory pressure (ZEEPe) or PEEPe. METHODS: Ten patients with COPD who were intubated and mechanically ventilated received fenoterol (10 mg/4 mL) via the ventilator using a jet nebulizer for 30 min on ZEEPe and PEEPe set at 80% of the total PEEP in a random order. The total resistance of the respiratory system (rapid airway occlusion technique), change in end-expiratory lung volume and expiratory flow limitation were assessed before and 5 min, 15 min, 30 min, 60 min and 240 min after fenoterol inhalation. RESULTS: Before inhalation and 60 min after inhalation, the total PEEP, the change in end-expiratory lung volume and the total resistance of the respiratory system were 8+/-3 cmH2O and 6+/-3 cmH2O, 0.61+/-0.34 L and 0.43+/-0.32 L, and 26+/-7 cmH2O/L/s and 23+/-6 cmH2O/L/s, respectively, with ZEEPe, and 9+/-3 cmH2O and 8+/-3 cmH2O (P<0.05 versus ZEEPe), 0.62+/-0.34 L and 0.62+/-0.37 L (P<0.05 versus ZEEPe), and 26+/-9 H2O/L/s and 25+/-9 H2O/L/s, respectively, with PEEPe. Three patients became not flow-limited under the combination of PEEPe and fenoterol. CONCLUSIONS: In patients with COPD, fenoterol combined with PEEPe has opposing effects on respiratory mechanics. First, it does not significantly reduce lung hyperinflation or inspiratory resistances. Second, it allows expiratory flow limitation reversal in some patients. These findings result from the net effect on end-expiratory lung volume of each intervention. This implies that if fenoterol is used in combination with PEEPe, the level of PEEPe should be reassessed during the time course of the drug to prevent any further lung hyperinflation.

Plasma and lung concentrations of ceftazidime administered in continuous infusion to critically ill patients with severe nosocomial pneumonia.

OBJECTIVE: To determine the steady-state plasma and epithelial lining fluid (ELF) concentrations of ceftazidime administered in continuous infusion to critically ill patients with severe nosocomial pneumonia. DESIGN: Prospective, open-label study. SETTING: An intensive care unit and research ward in a university hospital. PATIENTS: A total of 15 adult patients with severe nosocomial bacterial pneumonia on mechanical ventilation were enrolled. INTERVENTIONS: All subjects received a 30 min intravenous infusion of 2 g ceftazidime followed by a continuous infusion of 4 g over 24 h. The concentrations of ceftazidime in plasma and ELF were determined at steady-state after 2 days of therapy by high performance liquid chromatography. MEASUREMENTS AND MAIN RESULTS: The mean +/-SD steady-state plasma and ELF concentrations of 4 g ceftazidime in continuous infusion were 39.6+/-15.2 microg/mL and 8.2+/-4.8 microg/mL, respectively, showing a mean +/-SD percentage penetration of ceftazidime into ELF of 20.6+/-8.9%. CONCLUSION: The administration of 4 g ceftazidime in continuous infusion in critically ill patients with severe nosocomial pneumonia provides concentrations in excess of the minimal inhibitory concentration of many susceptible organisms over the course of therapy both in serum and ELF. However, for some pathogens such as P. aeruginosa, higher doses of ceftazidime should be administered, or another agent should be used in combination.