Thrombogenic side-effects of recombinant factor VIIa after use in coronary artery bypass surgery.

Recombinant activated factor VII (rFVIIa) has been used 'off licence' to successfully treat bleeding and reduce transfusion requirements in complex cardiac surgery. However; concerns over thrombogenic side-effects have limited but not excluded its use in patients undergoing coronary artery bypass surgery (CABG). We present two cases of CABG (one 'on pump' and one 'off pump') which were complicated by intraoperative aortic dissection and severe bleeding. In both cases the bleeding was successfully treated with rFVIIa. However the first case suffered from severe postoperative arrhythmias, myocardial infarction, cardiac arrest and worsening left ventricular dysfunction, suggesting graft patency may have been impaired, whereas the second case remained symptom-free suggesting graft patency was unaffected by the use of rFVIIa. If rFVIIa is needed to treat bleeding during CABG surgery, it may be more appropriate to administer smaller, repeated doses to minimize the risk of thrombosis and early graft failure.

Left ventricular volume reduction: new dawn or false horizon? Basic science and clinical doubts.

Left ventricular volume reduction surgery (LVVR) for end-stage dilated cardiomyopathy is a surgical option used selectively but with unclear long-term results. Increasing numbers of reports are appearing in the literature. These should be pooled into an international registry through collaborative efforts that allow for more effective analysis. Furthermore, high priority must be given to identify subgroups of patients who will potentially gain most benefit from LVVR. Basic science may add invaluable data and in this article we describe how intraoperative myocardial biopsies from patients with idiopathic dilated cardiomyopathy were utilized to isolate myocytes in an effort to determine differential physiological characteristics at the cellular level. The result showed various degrees of contractile anomalies in response to electrical stimulation associated with defective calcium handling as reflected by measurements of calcium transients. It is hoped that this approach may be extended to preoperative catheter biopsy to gain information that will facilitate patient selection to avoid unnecessary surgical failures.

Effect of P6 acupressure on postoperative vomiting in children undergoing outpatient strabismus correction.

A prospective, double-blind study was conducted to compare the effect of pressure at the P6 (Neikuan) point with placebo as an antiemetic in children. Sixty-six patients, ages 3-12 yr, undergoing outpatient surgery for correction of strabismus, were allocated randomly to receive either bilateral P6 acupressure or placebo during the perioperative period. The study was designed to detect a 50% difference in the incidence of postoperative vomiting between the two groups, with a 90% power of achieving a statistically significant result at the 5% level (two-tailed). The incidence of postoperative vomiting for the placebo group was 58% before discharge from hospital, 73% at home and 82% in the first 24 h after surgery. The corresponding results for the acupressure group were 58% before discharge, 71% at home and 94% in the first 24 h. These differences were not significant; P6 acupressure did not reduce the incidence of postoperative vomiting in children undergoing strabismus surgery.

Postoperative analgesia for haemorrhoidectomy. A comparison between caudal and local infiltration.

This study compared the analgesic effectiveness of local infiltration of bupivacaine with caudal extradural bupivacaine in the first 48 hours after haemorrhoidectomy. Surgical and anaesthetic protocol was rigidly standardised. The caudal group had significantly less pain in the first 6 hours after haemorrhoidectomy, and on first bowel opening, when compared to those who received local infiltration of bupivacaine. There was no significant difference between the two groups with respect to further analgesic requirements, complications, time to first bowel action, and duration of hospital stay. The definite advantage of caudal extradural bupivacaine for haemorrhoidectomy must be balanced against the rare but potentially serious complications associated with its use.

Ventilator disconnexion alarm failures. The role of ventilator and breathing system accessories.

Pressure-sensitive ventilator disconnexion alarms do not always alarm during disconnexion of a discharging compliance ventilator such as Manley Blease, unless accurately adjusted. High flows during disconnexion result in significant pressure generation caused by outflow resistance of catheter mounts, heat and moisture exchangers, capnometer cuvettes, and angled connectors; this may lead to alarm failure because of incorrectly adjusted pressure alarm limits. The exact position of the disconnexion is critical and if the alarm's pressure sensor is placed in either the inspiratory or expiratory limb of the ventilator it makes no difference to its correct function. Nine different heat and moisture exchanges were compared in the same breathing system. Those with 15-mm male connectors generate the highest pressures on disconnexion (1.1 kPa). It is suggested that the low pressure alarm limit is set only marginally below the peak inspiratory pressure, and that it is readjusted for every patient and after every change in ventilation. Most importantly, the alarm should be shown to be functional by a trial disconnexion at the tracheal tube.

Irreversible inhibition of epithelial sodium channels by ultraviolet irradiation.

1 The effects of u.v. irradiation at 254 nm and 350 nm on sodium transport across frog skin epithelium have been investigated. 2 Irradiation at 254 nm but not at 350 nm produces a dose-dependent, functionally selective blockade of sodium transport. The effect is apparently due to the irreversible closure of apical sodium channels. 3 The amiloride-sensitive conductance was directly related to sodium transport as measured by short circuit current (SCC) both in normal and irradiated tissues, although both conductance and current were reduced in irradiated tissues. 4 The sensitivity of epithelia to irradiation at 254 nm was defined from the rate constants for the decline in SCC during three 2 min periods of irradiation at 1850 microW cm-2. The rate constant for the initial 2 min irradiation was 0.093 +/- 0.008 min-1. 5 Lowering the sodium concentration to 5.5 mM from 110 mM increased the rate constant to 0.141 +/- 0.014 min-1, consistent with the view that more functional sodium channels exist at lowered sodium concentration. 6 Lowering the temperature to 7 degrees C from 23 degrees C reduced the rate constant to 0.032 +/- 0.007 min-1 suggesting that blockade of channels is not due to a direct interaction with photons. 7 Using a variety of experimental protocols we were unable to demonstrate that bromamiloride or iodoamiloride can act as photoligands for sodium channels in the epithelium of Rana temporaria. This is in contrast to earlier reports with other epithelia.