Jean Lumley

Propofol for long-term sedation in the intensive care unit A comparison with papaveretum and midazolam*

Thirty‐seven patients with a wide range of illnesses were studied during mechanical ventilation of the lungs in an intensive care unit. Fifteen were sedated with a continuous propofol infusion, with analgesia provided by bolus doses of papaveretum. Twelve received a continuous infusion of papaveretum, supplemented by bolus doses of midazolam. The level of sedation was assessed every four hours and measurements were made of haemodynamic and respiratory variables. Levels of sedation were generally satisfactory in both groups. Six patients who received propofol required the use of muscle relaxants, because of their strong respiratory drives, to achieve synchronisation with the ventilator. There was no significant difference in respiratory or haemodynamic variables between the groups, but several patients required inotropic support because of their disease. There was no evidence of inhibition of adrenal steroidogenesis in the propofol group. Propofol can be a useful sedative agent in the intensive care unit, but sedative regimens should be tailored to individual patient requirements.

ETOMIDATE, A NEW WATER-SOLUBLE NON-BARBITURATE INTRAVENOUS INDUCTION AGENT

This paper describes clinical experimence, in 100 patients, with the new non-barbiturate, water soluble induction agent, etomidate. This drug produces sleep in one arm/brain circulation-time. There was no effect on pulse-rate, a slight fall in blood-pressure, and a low frequency of apnoea. Involuntary movements were noted, and in some patients these were severe. Etomidate warrants further evaluation as an intravenous induction agent.

ICI 35868 (Diprivan): a new intravenous induction agent. A comparison with methohexitone.

ICI 35868 (Diprivan) has been used as an induction agent in patients undergoing minor gynaecological surgery and as the sole anaesthetic agent during bronchoscopy, and its effects were compared with those of methohexitone. The new agent proved to be satisfactory, although induction of anaesthesia was significantly longer than following methohexitone. Complications were similar with both drugs. ICI 35868 deserves full investigation as an intravenous anaesthetic agent.

Sedation for local anaesthesia. Comparison of intravenous midazolam and diazepam

Intravenous midazolam and diazepam have been compared as sedatives during surgery performed under local anaesthesia. Satisfactory conditions were produced by both drugs. No difference was detected in the rate of recovery, but a highly significant greater degree of amnesia followed the use of midazolam.

Continuous intravenous infusion of disoprofol (ICI 35868, Diprivan). Comparison with Althesin to cover surgery under local analgesia.

Disoprofol has been used to induce and, by continuous infusion, to maintain a light level of general anaesthesia in 100 patients undergoing surgery with the aid of a regional block. Its effects have been compared with 100 patients anaesthetised in a similar manner with Althesin. Disoprofol proved to be a very satisfactory agent for use by this method and apart from an appreciable incidence of pain on injection the number of complications‘was small and comparable to those found with Althesin, which caused more involuntary movements. Recovery was particularly rapid and clear‐headed following disoprofol, and occurred highly significantly more quickly than after Althesin. Disoprofol, however, will not be marketed in the present formulation which has Cremophor EL as the solubilising agent.

Amniotic fluid embolism. A report of three cases.

Three patients showing the typical features of amniotic fluid embolism are described. Two survived the insult, while in the third the diagnosis was confirmed by post-mortem histological examination of the lungs.

NO BLOOD OR BLOOD PRODUCTS

There are said to be 3 750 000 Jehovah’s Witnesses worldwide, 140 000 of whom live in the United Kingdom. They originated in the late 1870s, when Charles Russell founded a Bible study group in Allegheny City, now a suburb of Pittsburgh, Pennsylvania. The group developed as a fundamentalist Christian sect which believed in a literal reading of the Bible. In 1931, they began calling themselves Jehovah’s Witnesses on the basis of Isaiah, where Jehovah (God) declares to his people, ‘ye are my witnesses’ (Isaiah; 43: 1&11). Jehovah’s Witnesses believe in the absolute authority of God, which transcends the power of governments and the law. Since their inception, they have predicted the imminent end of the world and the creation of a new earth by God, upon which faithful witnesses will enjoy eternal life [ 11. They would, therefore, rather die than live in a way which would contravene their interpretation of the Bible. The first issue of a journal, Zion’s Watchtower and Herald of Christ’s Presence, was published in 1879. This continues today as The Watchtower, the monthly journal of the Jehovah’s Witnesses. It is printed in over 100 languages and is distributed worldwide. In July 1945, an article in The Watchtower quoted several passages from the Bible to show that blood transfusion should be forbidden as it violated God’s law [ 2 ] . These included the statement from Leviticus quoted above, and also Genesis; 9: 3 4 , ‘Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things. But the flesh is the life thereof, which is the blood thereof, ye shall not eat.’ The quotes relate to either the oral ingestion of blood, or of meat which has not been exsanguinated. This has been extrapolated to include receiving blood by the intravenous route. Since July 1945, Jehovah’s Witnesses have refused transfusions of whole blood. This refusal now extends to packed red cells, plasma and platelets [3]. The use of albumin, immune globulins and clotting factors is not strictly forbidden by their Church and is left to the conscience of the individual member. The extracorporeal circulation of an individual’s own blood is permitted, providing it does not lose contact with that individual’s circulation. If blood does lose contact with an individual’s intravascular contents, it is considered spilt and may not be re-infused. So, while cardiac bypass is acceptable, autologous blood transfusion is not. Some Jehovah’s Witnesses will agree to the intra-operative use of a cell saver machine, although this does not maintain continuity with the circulation [4]. What are the legal implications for anaesthetists dealing with patients who refuse blood? For an elective case, the anaesthetist is entitled to refuse to be involved. In a hospital emergency, however, an anaesthetist who is on duty is bound, both ethically and by their contract of employment, to treat patients. When a doctor undertakes the care of any patient, a contractual agreement is entered into with that patient to treat them according to their wishes, if they are able to express them. A competent adult has an absolute right to refuse any aspect of medical treatment. ‘It matters not whether the reasons for the refusal are rational or irrational, unknown or even non-existent’ [5]. If a patient is treated against their will, the tort (civil wrong) of battery is committed. Therefore, if blood has been refused by a patient, it may not be given. The management of these patients must, if at all possible, be planned and should involve senior clinicians. The nature of the procedure and the element of risk should be explained to the patient. Pressure to refuse blood products is often exerted on Jehovah’s Witnesses by other members of their church. It is important, therefore, that they are seen alone pre-operatively and that the anaesthetist determines exactly what forms of treatment the patient accepts or refuses. The possible consequences of refusing blood products, including death, should be made clear to the patient. This refusal must then be documented on a special consent form and witnessed by another doctor [6]. Many Jehovah’s Witnesses carry a signed card to express their wishes in case of an emergency. In the recent Canadian case of Malette v Shulman [7, 81, Mrs Malette, a Jehovah’s Witness, presented unconscious and in hypovolaemic shock. She carried a signed card refusing blood. The card was printed in French. Translated into English, it read:

Methohexitone and etomidate for bronchoscopy.

General anaesthesia for bronchoscopy has been provided with either methohexitone or etomidate, with and without fentanyl. Recovery was faster following methohexitone and there was no statistically significant difference in the incidence of complications. Inclusion of fentanyl in the technique did not confer any benefits with either drug.

Initial experience with Minaxolone. A water-soluble steroid intravenous anaesthetic agent.

Minaxolone has been used to induce anaesthesia, and in incremental doses to supplement nitrous oxide, in 100 patients undergoing minor surgical procedures. Half the patients received a small dose of fentanyl before induction. Minaxolone proved to be a satisfactory induction agent. The commonest complications were an increase in muscle tone and imoluntary muscle movements, which in some patients occurred in the recovery period: their incidence was reduced by fentanyl. There was a notably low incidence of nausea and romiting.Summary Minaxolone has been used to induce anaesthesia, and in incremental doses to supplement nitrous oxide, in 100 patients undergoing minor surgical procedures. Half the patients received a small dose of fentanyl before induction. Minaxolone proved to be a satisfactory induction agent. The commonest complications were an increase in muscle tone and imoluntary muscle movements, which in some patients occurred in the recovery period: their incidence was reduced by fentanyl. There was a notably low incidence of nausea and romiting.

Suxamethonium apnoea masked by tetrahydroaminacrine

A case is reported of a patient who was given THA with suxamethonium and who demonstrated a prolonged apnoea. This patient was later shown to have a variant cholinesterase enzyme. The different techniques of THA and suxamethonium administration are discussed and it is suggested that an initial dose of suxamethonium should precede a THA-suxamethonium combination in order to try and avoid a prolonged apnoea.