Ethical emergencies and ethical consultations.
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Critical Care↗
Biomedical subjects
I S Grant
Publications and source records attributed to I S Grant.
The relationship of blood lactate concentrations, oxygen delivery and oxygen consumption in septic shock and the adult respiratory distress syndrome.
Tissue hypoxia is thought to be pivotal to the development of multiple organ failure, but cannot be measured directly in clinical practice. We assessed the relationship between initial arterial blood lactate concentrations and the presence of the phenomenon of delivery-dependent oxygen consumption, both of which may indicate tissue hypoxia. Twenty-three critically ill patients with septic shock and adult respiratory distress syndrome were studied prospectively and allocated to one of two groups according to blood lactate concentrations. In group 1, blood lactate concentration was less than the level widely accepted as significant (2 mmol.l-1); in group 2, the concentration exceeded 2 mmol.l-1. In both groups, resuscitation with colloid, blood and vasoactive drugs resulted in significant increases in oxygen delivery; in group 1 (n = 13), mean (SEM) oxygen delivery increased from 484 (36) to 730 (44) ml.min-1.m-2 (p < 0.005) and in group 2 (n = 10) from 550 (54) to 780 (54) ml.min-1.m-2 (p < 0.05). In neither group was there a significant change in oxygen consumption. However, there were individuals in both groups who exhibited pathological delivery dependence. This suggests that the absence of hyperlactataemia does not preclude delivery dependence of oxygen consumption with the attendant potential for tissue hypoxia.
Adult↗
Adrenaline in treatment of septic shock: effects on haemodynamics and oxygen transport.
The effects of adrenaline on haemodynamics and oxygen transport were studied in 13 patients with septic shock persisting after optimal fluid loading. Adrenaline was administered by intravenous infusion at an increasing dose until no further benefit was seen. There were significant increases in mean arterial pressure, cardiac index, left ventricular stroke work index and oxygen delivery index. There was no significant change in oxygen consumption although the trend was towards an increase. There was a significant reduction in oxygen extraction ratio, but no change in shunt fraction. Adrenaline would appear to have beneficial haemodynamic effects in septic shock.
Aged↗
The haemodynamic effects of intermittent haemofiltration in critically ill patients.
The haemodynamic effects of intermittent high volume venovenous haemofiltration were studied in 13 critically ill patients. The mean negative fluid balance during filtration was 1.21 and the mean duration of treatment 3 h 40 min. The cardiac index fell initially (4.5 +/- 0.2 to 3.8 +/- 0.21/min/m2; p less than 0.05) but then remained stable throughout treatment before returning to baseline at the end of haemofiltration. The mean arterial pressure was unchanged with an increase in the systemic vascular resistance (651 +/- 33 to 765 +/- 65 dyne.s/cm5; p less than 0.05) suggesting that vascular responsiveness is maintained during haemofiltration.
Acute Kidney Injury↗
Withdrawal syndrome after propofol.
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Anesthesia, Intravenous↗
Pneumocystis carinii pneumonia in thymoma with hypogammaglobulinaemia: successful outcome of therapy including i.v. IgG replacement.
A 66-year-old patient presented with Pneumocystis carinii Pneumonia (PCP) and was found to have hypogammaglobulinaemia, associated with a thymoma that had been resected 17 months earlier. Only one previous case of PCP in association with a thymoma and hypogammaglobulinaemia has been reported, in which the patient died. We report another such patient who was successfully treated with a combination of intravenous immunoglobulin and high dose cotrimoxazole.
Agammaglobulinemia↗
Lactate and acid base changes in the critically ill.
Metabolic acidosis and hyperlactataemia are important, independent findings in acute illness, and the combination of these abnormalities carries a grave prognosis. Despite this there is still controversy about the most appropriate therapy of lactic acidosis, and the relationship of commonly used acid base measurements to blood lactate levels. This paper details studies in shock and multiple organ failure examining these issues. Shocked patients were studied during catecholamine therapy and showed improvements in acidosis and hyperlactataemia in conjunction with cardiorespiratory improvement. This supports a beneficial role for these agents in appropriately monitored, volume resuscitated and oxygenated patients with shock and lactic acidosis. Assessment of differences in mixed venous and arterial acid base status was performed in 32 patients. The relationship of blood lactate to acid base measurements was examined. There were no significant differences in [H+], [HCO3] or base excess. There was no significant correlation between any of these in arterial or mixed venous samples and arterial whole blood lactate. Mixed venous PCO2 was significantly higher than arterial PCO2. Haemodynamic, oxygen transport and acid base changes were documented in eight patients with multiple organ failure being treated by intermittent high volume haemofiltration (Gambro AK10 system) with lactate buffered replacement fluid PCO2 (Gambro haemofiltrasol). Cardiac output and oxygen delivery fell significantly during therapy but blood pressure was maintained by an increase in systemic vascular resistance as we have shown previously. Serious acid base derangements were not seen. Significant hyperlactataemia was present throughout haemofiltration as a result of the infusion of replacement fluid containing 45 mmol/l lactate. The only alterations in acid base status were transient falls in arterial bicarbonate and base excess at one hour.
Acidosis, Lactic↗
Goitre in northern Pakistan.
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Geological Phenomena↗
Encephalitis lethargica.
We report a case of encephalitis lethargica, who presented major intensive care problems, particularly with respect to hyperirritability and convulsions, but who went on to complete recovery. This case would encourage a more aggressive attitude to the management of encephalitis.
Adult↗
Reversal of midazolam sedation with flumazenil following conservative dentistry.
The purpose of this double-blind randomized study was to assess recovery of mental function following reversal of midazolam-induced sedation with the specific antagonist flumazenil (R015-1788) or placebo following conservative dental procedures. Recovery was assessed using choice reaction time and critical flicker fusion threshold, both objective tests of psychomotor function; linear analogue sedation scores and simple memory tests. Assessments were repeated up to 3 h after administration of flumazenil or placebo to discover whether recovery was sustained or whether resedation occurred due to the short duration of action of flumazenil. Flumazenil in doses from 0.5 to 1.0 mg rapidly reversed the sedative and amnesic effects of a mean dose of 8.2 mg of midazolam without apparent evidence of subsequent resedation. Since recovery of mental function in the control group had ordinarily occurred 45 min after administration of placebo, routine reversal of midazolam sedation with flumazenil cannot be justified. Nevertheless, in cases of undue sedation persisting after dental treatment, flumazenil may be used with minimal risk of resedation occurring.
Adolescent↗
Sedation during spinal anaesthesia: comparison of propofol and midazolam.
Propofol and midazolam were compared in 40 patients undergoing orthopaedic surgery under spinal anaesthesia. An infusion of either 1% propofol or 0.1% midazolam was given at a rate adjusted to maintain a similar level of sedation. The mean time to reach this required level was similar in both groups. Quality and ease of control of sedation were good in all patients. A mean infusion rate of 3.63 mg kg-1 h-1 was required for propofol and 0.26 mg kg-1 h-1 for midazolam. Immediate recovery, as judged by ability to open eyes and recall date of birth, was significantly more rapid following propofol (P less than 0.001). Similarly, restoration of higher mental function was significantly faster following propofol, measured by choice reaction time and critical flicker fusion threshold. Amnesia for the immediate postoperative period was significantly greater after midazolam (P = 0.0001).
Anesthesia Recovery Period↗
Propofol infusion for control of status epilepticus.
Two patients with status epilepticus who were resistant to conventional treatment but responded to propofol infusions are reported. An electroencephalogram confirmed the seizures and their successful treatment.
Adult↗
Low-dose intrathecal diamorphine analgesia following major orthopaedic surgery.
In a randomized double-blind study we examined the effect of adding diamorphine 0.25 mg and 0.5 mg to intrathecal bupivacaine anaesthesia for major orthopaedic surgery. Duration of postoperative analgesia was considerably greater in patients given either doses of intrathecal diamorphine than in a control group of patients given bupivacaine alone (P less than 0.001). However, there was no significant difference between the two diamorphine doses (0.25 mg and 0.5 mg), each providing prolonged analgesia (10.8 and 9.9 h, respectively). Although there was no evidence of late respiratory depression, the frequency of adverse effects, in particular urinary retention, nausea and vomiting, was high in both groups receiving intrathecal diamorphine.
Aged↗
Relative potencies of propofol and methohexitone infusions.
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Anesthesia Recovery Period↗
Effect of the addition of adrenaline to extradural diamorphine analgesia after caesarean section.
In a randomized double-blind study the effect of the addition of adrenaline to extradural diamorphine was assessed in 54 patients after Caesarean section. Patients received extradural diamorphine 5 mg in saline 10 ml with or without adrenaline 1 in 200,000 for postoperative pain relief. Analgesia was profound and of rapid onset in both groups. Duration of analgesia was greater in the adrenaline group (time to next analgesia 12.51 +/- 0.94 h, mean +/- SEM), than in the saline group (9.87 +/- 0.98 h) (P = 0.057). Analgesia was also more consistent in the adrenaline group, with 77% of patients having more than 8 h of good analgesia compared with 48% in the saline group (P less than 0.05). Plasma morphine concentrations, measured in 12 patients, were lower, although not significantly so, in the adrenaline group and mean time to peak concentration markedly delayed. No serious side effects were observed, but there was a higher incidence of vomiting in the adrenaline group.
Cesarean Section↗
The analgesic effects of ketamine.
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Analgesics↗
Propofol for induction of anaesthesia in children. A comparison with thiopentone and halothane inhalational induction.
The induction characteristics, dosage requirements, cardiovascular and respiratory effects of propofol with added lignocaine were compared with those of thiopentone and halothane inhalational induction in two groups of children aged 1-5 years and 5-10 years. Propofol induction produced significantly greater decreases in blood pressure, particularly in the 1-5 year age group. Heart rate was maintained well with all three induction techniques. Pain on injection into a vein on the dorsum of the hand was significantly more common with propofol despite the addition of lignocaine. However, this was mild in the majority of children and did not interfere with the induction of anaesthesia. The incidence of respiratory depression and other adverse effects was low with all three induction methods. The mean induction doses of both intravenous agents were greater in the 1-5-year age group. The ratio of thiopentone to propofol dose was approximately 2.5:1 in both age groups. The high incidence of pain on injection with propofol may prove to be a significant drawback to its otherwise satisfactory use in children.
Anesthesia, Inhalation↗
A comparison of propofol and midazolam by infusion to provide sedation in patients who receive spinal anaesthesia.
Twenty patients scheduled for orthopaedic surgery under spinal anaesthesia received by intravenous infusion either 1% propofol or 0.1% midazolam at a rate adjusted to maintain adequate sedation as judged on a five-point scale. No other anaesthetic or analgesic drugs were given. The mean time to reach the required level of sedation was similar in both groups and the quality and ease of control of sedation were good in all patients. Mean infusion rates were 3.73 mg/kg/hour for propofol and 0.27 mg/hg/hour for midazolam. Airway maintenance was excellent and there were no side effects other than restlessness of the arms in one patient in each group. Recovery, judged by ability to open the eyes and recall date of birth, was significantly more rapid after propofol than after midazolam (2 and 10 minutes respectively after the end of infusion) and two patients in the latter group were unduly drowsy in the initial postoperative period. Pre- and postoperative amnesia were greater in the midazolam group but no patient had recall of peri-operative events. Psychometric tests showed significantly better recovery of higher mental function after propofol for up to 2 hours after surgery.
Anesthesia Recovery Period↗