Serous retinal detachment — an unusual complication of preeclampsia

A case of preeclampsia complicated by serous retinal detachment is described. The anaesthetic implications are discussed.     

Patients'attitudes to rectal drug administration

One hundred adult patients attending for day case surgery were surveyed by anonymous questionnaire in order to determine their attitudes to rectal drug administration. Fifty four patients did not want an analgesic drug (diclofenac sodium) administered rectally whilst under anaesthesia, all preferring to take it orally if available. Ninety eight patients thought that drugs administered per rectum should always be discussed with them beforehand and a few had very strong feelings about this route of administration. We suggest that prescribers of rectal diclofenac should always discuss it with patients pre-operatively. Whilst many are happy to have suppositories, some young patients are sensitive about this and prefer to take such medication by mouth.     

Oral midazolam premedication for paediatric day case patients

Forty-nine children having day-stay surgical procedures were randomly assigned to receive oral midazolam 0.75 mg·kg^?1 or placebo in a double blind fashion. The child's level of anxiety was assessed before premedication using parental, child and observer scales. The child and observer anxiety scores were repeated in the anaesthetic room. Most children presented for anaesthesia in a calm state, irrespective of whether they had received midazolam. Parents tended to overestimate their child's level of anxiety. Observer anxiety scores reliably predicted behaviour during induction of anaesthesia in the absence of a sedative. Observer scores decreased in the midazolam group (P<0.02), but not in the placebo group, children below six years having the greatest decrease with midazolam. The median time to discharge from hospital was delayed by 30 min in the midazolam group (P<0.01). Children do not require routine sedative premedication for day case procedures, but oral midazolam is useful in producing calm behaviour in those children with high observer anxiety scores.     

MEASUREMENTS OF INTERFACE PRESSURE BETWEEN BODY SITES AND THE SURFACES OF FOUR SPECIALISED AIR MATTRESSES

SUMMARY Four specialised air mattresses had interface pressure measured under six body sites prone to pressure sores in 10 subjects, supine and sitting. The mattresses were the Clinirest (SSI) and FirstStep (KCI) continuous airflow mattress overlays, and Airwave (Pegasus) and Nimbus (Huntleigh) alternating pressure air mattresses. On the mattress overlays, average supine interface pressures were 2.33 kPa (scapula), 4.15 kPa (elbow), 1.94 kPa (sacrum) and 2.79 kPa (buttock), although they were higher at the occiput (7.97 kPa) and heel (11.7 kPa). The alternating pressure air mattresses had an average minimum interface pressure close to zero for three sites, rising to 4.28 kPa under the heel. Average maximum interface pressures were 8.61 kPa (occiput), 5.21 kPa (scapula), 4.90 (elbow), 4.85 kPa (sacrum), 4.61 kPa (buttock) and 13.2 kPa (heel). No accepted scientific method exists for comparing the two types of mattress. Our data suggest a clinical benefit at the occiput and heel (supine) in using an alternating pressure air mattress and a benefit in using a continuous airflow mattress overlay at other sites.     

A randomized controlled trial of sedation in the critically ill

A randomized controlled trial comparing: a) a combination of oral chloral hydrate and promethazine to b) a continuous intravenous midazolam infusion, for maintenance sedation in critically ill children, was carried out. The level of sedation was assessed four hourly using a specifically devized sedation scale. Forty-four children entered the study of whom two were subsequently excluded. The number of satisfactory assessments (desired and actual levels of sedation equal) was significantly greater in the chloral hydrate and promethazine group (Chi-squared P <0.01; confidence intervals of the difference 0.06 to 0.20). The number of assessments at level 5 on the sedation scale (patient restless/distressed) was significantly greater in the midazolam group (Chi-squared P <0.05). The total number of satisfactory assessments in the two groups were only 61 and 48% respectively, suggesting that sedation can be considerably improved. Chloral hydrate and promethazine are more effective than midazolam as maintenance sedation in critically ill children. It is possible to prospectively study the efficacy of sedative drugs in critically ill children.     

Reduction by Fentanyl of the Cp sub 50 Values of Propofol and Hemodynamic Responses to Various Noxious Stimuli

Background: Propofol and fentanyl infusion rates should be varied according to the patient's responsiveness to stimulation to maintain satisfactory anesthetic and operative conditions. However, somatic and autonomic responses to various noxious stimuli have not been investigated systematically for intravenous propofol and fentanyl anesthesia.

Methods: Propofol and fentanyl were administered via computer-assisted continuous infusion to provide stable concentrations and to allow equilibration between plasma-blood and effect-site concentrations. The propofol concentrations needed to suppress eye opening to verbal command and motor responses after 50-Hz electric tetanic stimulation, laryngoscopy, tracheal intubation, and skin incision in 50% or 95% of patients (Cp50 and Cp95) were determined at fentanyl concentrations of 0.0, 1.0, 2.0, 3.0, and 4.0 ng/ml in 133 patients undergoing lower abdominal surgery. The ability of propofol with fentanyl to suppress hemodynamic reactions in response to various noxious stimuli also was evaluated by measuring arterial blood pressure and heart rate before and after stimulation.

Results: The various Cp50 values for propofol alone (no fentanyl) for the various stimuli increased in the following order: Cp sub 50loss of consciousness, 4.4 micro gram/ml (range, 3.8-5.0); Cp50tetanus, 9.3 micro gram/ml (range, 8.3-10.4); Cp50laryngoscopy, 9.8 micro gram/ml (range, 8.9-10.8); Cp50skin incision, 10.0 micro gram/ml (range, 8.1-12.2); and Cp50intubation, 17.4 micro gram/ml (range, 15.1-20.1; 95% confidence interval). The reduction of Cp50loss of consciousness, with fentanyl was minimal; 11% at 1 ng/ml of fentanyl and 17% at 3 ng/ml of fentanyl. A plasma fentanyl concentration of 1 ng/ml (3 ng/ml) resulted in a 31-34% (50-55%) reduction of the propofol Cp50 s for tetanus, laryngoscopy, intubation, and skin incision. Propofol alone depresses prestimulation blood pressure but had no influence on the magnitude blood pressure or heart rate increase to stimulation. Propofol used with fentanyl attenuated the systolic blood pressure increases to various noxious stimuli in a dose-dependent fashion.     

Release of Proinflammatory Cytokines During Pediatric Cardiopulmonary Bypass: Heparin-Bonded Versus Nonbonded Oxygenators

Background. Heparin bonding of the cardiopulmonary bypass (CPB) circuit may be associated with a reduced inflammatory response and improved clinical outcome. The relative contribution of a heparin-bonded oxygenator (ie, >80% of circuit surface area) to these effects was assessed in a group of pediatric patients.

Methods. Twenty-one pediatric patients undergoing CPB operations were assigned randomly to receive either a heparin-bonded oxygenator (group H, n = 11) or a nonbonded oxygenator (group C, n = 10) in otherwise nonbonded circuits. The two groups were similar in pathology, age, weight, CPB time, and cross-clamp time. Plasma levels of the cytokines tumor necrosis factor-, interleukin-6, and interleukin-8, as well as terminal complement complex, neutrophils, and elastase, were analyzed before, during, and after CPB.

Results. Significant levels of tumor necrosis factor- were not detected in either group. Plasma levels of all other markers increased during and after CPB compared with baseline. Plasma levels of interleukin-6 peaked in both groups 2 hours after the administration of protamine but remained significantly higher in group C 24 hours after operation. Plasma concentrations of interleukin-8 peaked at similar levels in both groups 30 minutes after protamine administration and returned to baseline thereafter. Levels of terminal complement complex and elastase peaked in both groups 30 minutes after protamine administration. Plasma levels of terminal complement complex were significantly higher at the end of CPB and after protamine administration in group C. Elastase levels were significantly higher 2 and 24 hours after CPB in group C. The ventilation time of patients in group H was significantly lower than that of patients in group C: 10 (range, 3 to 24) versus 22 (range, 7 to 24) hours, respectively (p < 0.01).

Conclusions. The present study confirms the proinflammatory nature of pediatric operations and demonstrates a lessened systemic inflammatory response with the use of heparin-bonded oxygenators. This is achieved without bonding of the entire circuit, which could have significant cost-benefit implications by negating the need for custom-built heparin-bonded circuitry.