Laminar airflow decreases microbial air contamination compared with turbulent ventilated operating theatres during live total joint arthroplasty: a nationwide survey.

BACKGROUND: Preventing surgical site infections and prosthetic joint infections is crucial for patient safety after total joint arthroplasty. Microbial air contamination has been suggested as a risk factor. Therefore, the ventilation system that will reduce air contamination most effectively in operating theatres (OTs) has been discussed. AIM: To determine whether laminar airflow (LAF) ventilation is superior to turbulent airflow (TAF) ventilation by looking at the colony forming units (cfu) count during live total hip and knee arthroplasties. Furthermore, to explore whether the number of OT personnel, door and cabinet lock openings and technical parameters of the ventilation systems have an impact on the number of cfu. METHODS: Active air sampling and passive sedimented bacterial load were performed in 17 OTs, equipped with either LAF or TAF ventilation, during 51 live surgeries while observations were noted. FINDINGS: LAF OTs reduced cfu counts compared with TAF OTs during live surgery (P<0.001). All LAF OTs provided ultraclean air whereas TAF had nine procedures exceeding the threshold of 10 cfu/m3. Door and cabinet lock openings and number of personnel did not influence the cfu count, while it decreased with increasing volume and total air change per hour (P<0.05). CONCLUSION: All LAF OTs had cfu counts within recommendations and provided lower cfu counts compared with TAF OTs. The number of OT personnel and total openings did not have an influence on cfu counts. Increased volume of the OT and total air change per hour showed a decrease in active cfu counts.

Paediatric airway management: basic aspects.

Paediatric airway management is a great challenge, especially for anaesthesiologists working in departments with a low number of paediatric surgical procedures. The paediatric airway is substantially different from the adult airway and obstruction leads to rapid desaturation in infants and small children. This paper aims at providing the non-paediatric anaesthesiologist with a set of safe and simple principles for basic paediatric airway management. In contrast to adults, most children with difficult airways are recognised before induction of anaesthesia but problems may arise in all children. Airway obstruction can be avoided by paying close attention to the positioning of the head of the child and by keeping the mouth of the child open during mask ventilation. The use of oral and nasopharyngeal airways, laryngeal mask airways, and cuffed endotracheal tubes is discussed with special reference to the circumstances in infants. A slightly different technique during laryngoscopy is suggested. The treatment of airway oedema and laryngospasm is described.

Pharmacokinetics of rectal paracetamol after repeated dosing in children.

Twenty-three children (aged between 9 weeks and 11 yr) were given paracetamol suppositories 25 mg kg-1 every 6 h (maximum 5 days) after major surgery and serum and saliva concentrations were measured. There was a good correlation (r = 0.91, P < 0.05) between saliva and serum concentrations. A one-compartment linear model with first-order elimination and absorption and lag-time was fitted to the data (ADAPT II). At steady state, the mean (SD) concentration was 15.2 (6.8) mg litre-1. Mean (SD) time to reach 90% of the steady state concentration was 11.4 (8.6) h. Body weight, age and body surface area were well correlated (P < 0.05) with clearance and apparent volume of distribution. There was no evidence of accumulation leading to supratherapeutic concentrations during this dosing schedule for a mean of approximately 2-3 days.

Distress at induction of anaesthesia in children. A survey of incidence, associated factors and recovery characteristics.

This study analysed the frequency of distress at induction (DAI) in 2122 paediatric patients. The data were analysed to assess predictors of DAI and to examine associations between predictors of DAI and recovery characteristics. Patient age, preoperative behaviour, premedication (oral midazolam, n = 480) and venue for anaesthesia induction were associated with changes in the incidence of DAI. Distressed preoperative behaviour was a good predictor of DAI in all age groups. Premedication reduced the incidence of DAI in children aged 0.5-2 years old, and in older children who were distressed preoperatively. Induction in the Day Surgery Unit was associated with a reduction of the incidence of DAI in younger children. Children with DAI were more likely to suffer from distress at arousal (P = 0.001). Average early recovery time was prolonged 4.4 minutes and average discharge time in day patients was delayed 36 minutes by the use of oral midazolam premedication. Premedication was not significantly associated with arousal distress. We conclude that a policy of optimizing nonpharmacological approaches for minimizing induction distress, combined with selective premedication with oral midazolam, can produce a low incidence of induction distress and adverse effects.

[Nasal catheters versus Hudson face mask in oxygen therapy]. / Nasalkateter versus Hudson-ansigtsmaske ved iltterapi.

Thirty-two females, ASA class I, scheduled for termination of pregnancy before the 13th week participated in the study. After induction of anaesthesia, a soft plastic catheter was inserted in the oropharynx and the patients were postoperatively monitored with a capnograph, which sampled in- and expired air from the catheter. In a randomized cross-over design the patients received oxygen therapy by the Hudson face-mask and a nasal cannula. Humidified and heated oxygen was given in both cases, using a flow of 15 litres per minute. The nasal cannula resulted in a significantly higher expired end-tidal O2-fraction (FETO2) compared to the Hudson mask. During the nasal cannula period the respiratory rate was significantly lower than during the face mask period. The end-tidal CO2 pressure (PETCO2) remained constant.

[Continuous monitoring of end-tidal CO2-tension in non-intubated patients]. / Kontinuerlig monitorering af sluttidal CO2-tension hos ikkeintuberede patienter.

We describe and evaluate a method for continuously monitoring end-tidal CO2 (PETCO2) in non-intubated, spontaneously breathing patients. In 18 ASA I patients scheduled for minor surgery a 3.3 mm (10 CH) soft plastic catheter was preoperatively inserted through one nostril placing the tip at the level of the epiglottis. In the recovery room a capnograph was connected to the catheter for monitoring PETCO2. We found no significant differences between arterial carbon dioxide tension (PaCO2) and PETCO2 obtained by the catheter (0.2 +/- 2.2 mmHg) or obtained by a maximal expiration through a mouthpiece (-0.8 +/- 2.8 mmHg). We tested the possibility of mixing expired air with supplementary oxygen via the other nostril at a flowrate of 15 litres min-1, and found no significant difference in PETCO2 with or without flow (0.0 +/- 0.9 mmHg). Values are mean +/- SD. In conclusion we find that this method allows accurate monitoring of PETCO2 in non-intubated, spontaneously breathing patients even at supplementary oxygen flow-rates of up to 15 litres min-1.

[Brachial plexus blockade via the interscalene port--for regional anesthesia/analgesia of upper extremities; use, application and risks]. / Plexus brachialis-blokade anlagt via skalenerporten--til regional anaestesi/analgesi af overekstremiteten; anvendelse, anloeggelse og risici.

The interscalene technique for brachial plexus anaesthesia is described. The method is suitable for anaesthesia of the upper extremity, especially when anaesthesia of the proximal part of the arm and the shoulder region is desired. The technique is also useful in paediatric cases. Side effects are few, but the risk of paralysing of the diaphragm makes this method inappropriate for patients with severe respiratory disease.

[Time consumption at an orthopedic operating theatre. Physicians' ability to predict their own time consumption]. / Tidsforbrug på en ortopaedkirurgisk operationsstue. Loegers evne til at forudsige eget tidsforbrug.

The aim of the study was to investigate the time spent on different procedures in an orthopaedic operating theatre, and to evaluate the ability of doctors to predict their own time consumption. Time schedules were registered for 146 operations, of these 104 were either knee or hip replacements. Sixty percent of the total time was spent on surgery. The median misjudgment was 15 minutes for surgeons and five minutes for anaesthetists. An improvement in the doctors' ability to predict their own time consumption in the course of the study period could not be demonstrated. Comparing the study period with the similar period the year before it was not possible to demonstrate a change in the number of cancelled operations or the number of days with overtime. Epidural anaesthesia with bupivacaine was the most time consuming anaesthesia, the differences between the other forms of anaesthesia used were insignificant.

[Measurement of systolic finger blood pressure with a pulse oximeter]. / Måling af systolisk fingerblodtryk ved hjaelp af pulsoximeter.

In order to investigate whether the pletysmographic curve on a pulse oximeter can be employed for measurement of the systolic finger blood pressure, the authors compared the method with a strain-gauge method and undertook 160 measurements with a finger cuff on 11 healthy volunteers. By varying the pressure in two cuffs placed on the arm, the blood pressure in the finger could be altered from normal to very low values. The difference between the connected values was analysed and it was found that the difference between strain-gauge and pulse oximeter measurements read on the printer on employment on a new volunteer will be -0.9 +/- 3.8 mmHg. If the blood pressure is read on a manometer, the same difference will be -1.5 +/- 5.2 mmHg. The authors consider that the method is interesting in view of future employment for assessment of the collateral circulation in the hand but they recommend further investigations on patients with occlusive arterioschlerotic disease in the upper limbs.

[Cannulation of the radial artery. Risks, effective examination methods and monitoring of the circulation in the hand during the procedure]. / Kanylering af a. radialis. Risici, relevante undersøgelsesmetoder og monitorering af håndens kredsløb i forbindelse med proceduren.

Cannulization of the radial artery with the object of continuous measurement of the blood pressure or repeated analyses of the arterial blood gases is an easy and relatively safe procedure. Thrombosis is observed in 25-40% of the cases. The frequency depends upon the condition of the patient, the cannula and technique of cannulization and duration of this. Permanent ischaemic damage resulting from thrombosis is, however, rare. Other complications of clinical significance are infections and vascular lesions which are, similarly, rare. Allen's test for assessing the collateral circulation of the hand has a high negative predictive value while the positive predictive value is so low that a positive test result does not exclude cannulization. In these cases, better assessment of the perfusion of the hand may be obtained by combining the test with pletysmography. After cannulization, it should be possible to monitor perfusion distal to the site of cannulization employing more recent pulse oximeters with the aid of the pletysmographic curve.