RE-EXPANSION OF ATELECTASIS DURING GENERAL ANAESTHESIA: A COMPUTED TOMOGRAPHY STUDY

Formation of atelectasis is one mechanism of impaired gas exchangeduring general anaesthesia. We have studied manoeuvres to re-expandsuch atelectasis in 16 consecutive, anaesthetized adults withhealthy lungs. In group 1 (10 patients), the lungs were inflatedstepwise to an airway pressure (Paw) of 10, 20, 30 and 40 cmH₂O In group 2 (six patients), three repeated inflations upto Paw = 30 cm H₂O were followed by one inflation to 40 cm H₂O.Atelectasis was assessed by analysis of computed x-ray tomography(CT). In group 1 the mean area of atelectasis in the CT scanat the level of the right diaphragm was 6.4 cm² at Paw = 0 cmH₂O, 5.9 cm² at 20 cm H₂O, 3.5 cm ² at 30 cm H₂O and 0.8 cm²at 40 cm H₂O, A Paw of 20 cm H₂O corresponds approximately toinflation with twice the tidal volume. In group 2 the mean areaof atelectasis was 9.0 cm² at Paw = 0 cm H₂O and 4.2 cm² afterthe first inflation to 30 cm H₂O. Repeated inflations did notadd to re-expansion of atelectasis. The final inflation (Paw= 40 cm H₂O) virtually eliminated the atelectasis. We concludethat, after induction of anaesthesia, the amount of atelectasiswas not reduced by inflation of the lungs with a conventionaltidal volume or with a double tidal volume ("sigh"). An inflationto vital capacity (Paw = 40 cm H₂O, however, re-expanded virtuallyall atelectatic lung tissue. (Br. J. Anaesth. 1993; 71: 788–795)     

An evaluation of the Rapid Infusion System

The performance of the Rapid Infusion System was evaluated in the laboratory. Using a conventional mixture of two units of packed red cells, two units of fresh frozen plasma and 500 ml crystalloid, a single line and a driving pressure of 300 mmHg, the highest flow in our study was 970 ml.min-1 (2.8 mm catheter, no stopcock). With a 1.6 mm venous cannula the measured flow was 640 ml.min-1. Additional diluting of the standard 'blood cocktail' did not add much to the performance of the system. When primed with tap water 21 degrees C (12 degrees C respectively), the fluid at the outlet of the system reached a maximum temperature of 37.8 degrees C (37.4 degrees C) after 6 min at a flow of 400 ml.min-1. At flows higher than 1150 ml.min-1 (priming with 12 degrees C tap water: 800 ml.min-1), the system slowed down to flows of 700 to 1000 ml.min-1 in order to maintain an adequate temperature. We conclude, that the Rapid Infusion System is a valuable tool for situations where a rapid but controlled replacement with warmed blood at rates up to at least 1100 ml.min-1 is needed. The use of large bore intravenous catheters and avoiding additional resistors such as standard 3-way stopcocks is highly recommended.     

Patient satisfaction with care in the intensive care unit: can we rely on proxies?

Background: To investigate whether next of kin can be addressed as proxy to assess patients' satisfaction with care in the intensive care unit (ICU). Methods: Prospective observational multicentre study. Two hundred and thirty‐five patients with an ICU length of stay of ≥2 days and 266 of their adult next of kin participated. Patient satisfaction was assessed by a questionnaire, distributed upon discharge from an ICU and compared with next of kin's answers. The possible range of answers was 0–100, with higher numbers indicating higher satisfaction. The main outcome measure was the extent of agreement between patients' satisfaction with care and the ratings of their next of kin. Results: Patients were most satisfied concerning physicians' competence (86.7±16.3), while least satisfaction was observed for the management of agitation and restlessness (78.2±23.5). There was no significant difference between next of kin's and patients' ratings. Agreement between patients and proxies was the highest concerning overall satisfaction (Cohen's κ 0.40) and the lowest for coordination of care (0.24). Spouses/partners had a higher agreement with the patients' ratings than other proxies. Conclusions: If the patient is unable to rate his satisfaction with care in the ICU, next of kin may be taken as an appropriate surrogate. Trial registration: The study has been registered at ClinicalTrials.gov, Reg No: NTC 00890513.