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Biomedical subjects

P J Stow

Publications and source records attributed to P J Stow.

14 recordsLinked to original sources
PubMed1996

Sepsis-induced vasoparalysis does not involve the cerebral vasculature: indirect evidence from autoregulation and carbon dioxide reactivity studies.

We have studied cerebral autoregulation and vasoreactivity to carbon dioxide in 10 patients with the sepsis syndrome receiving intensive therapy. All patients were sedated with infusions of midazolam and fentanyl, and their lungs were ventilated mechanically with oxygen-air to maintain normoxia and normocapnia. Inotropic support and antibiotics were administered as necessary. During a period of constant level of sedation and stable haemodynamics, cerebral autoregulation was tested by increasing mean arterial pressure (MAP) by 23 (SD 2) mm Hg from baseline with an infusion of phenylephrine and simultaneously recording middle cerebral artery blood flow velocity (vmca) using transcranial Doppler ultrasonography. Carbon dioxide reactivity was tested by varying PaCO2 between 3.0 and 7.0 kPa and simultaneously recording vmca. There was no significant change in vmca (57 (22) and 59 (23) cm s-1) during the increase in MAP (75 (11) to 98 (10) mm Hg). The mean index of autoregulation (IOR) was 0.92 (SEM 0.03), which was not significantly different from 1, indicating near perfect autoregulation. Although absolute carbon dioxide reactivity was lower than reported previously in awake subjects, relative carbon dioxide reactivity was within normal limits for all patients (11.6 (SEM 0.8) cm s-1 and 20.3 (3) % kPa-1, respectively). We conclude that cerebral carbon dioxide reactivity and pressure autoregulation remained intact in patients with the sepsis syndrome, providing indirect evidence that at least in the early stages of the syndrome, the widespread sepsis-induced vasoparalysis does not involve the cerebral vasculature.

Adult↗
PubMed1993

Prolonged use of isoflurane in a patient with tetanus.

We describe a patient with tetanus, who received isoflurane for sedation to facilitate controlled mechanical ventilation. Isoflurane was administered for 34 days, resulting in a sustained serum inorganic fluoride ion concentration in excess of 50 mumol litre-1 and a peak serum inorganic fluoride ion concentration of 87 mumol litre-1. Although these concentrations are potentially nephrotoxic, no toxicity was evident clinically.

Adult↗
PubMed1989

Analgesia following inguinal herniotomy or orchidopexy in children: a comparison of caudal and regional blockade.

The effectiveness of postoperative analgesia was compared in 44 children undergoing inguinal surgery, 19 of whom received caudal analgesia (1 ml 0.2% bupivacaine/kg) and 25 ilioinguinal block (0.25 ml 0.5% bupivacaine/kg). The requirement for supplementary analgesia (intramuscular morphine) was less in the caudal group, although this did not reach statistical significance in the number studied. Ilioinguinal and caudal blockade both provide useful postoperative analgesia for children following ilioinguinal surgery.

Analgesia↗
PubMed1988

Arterial oxygen saturation following premedication in children with cyanotic congenital heart disease.

To determine the effects of premedication on arterial oxygen saturation (SaO2) and heart rate (HR), 11 children (ages three to seven years) scheduled for elective repair of cyanotic congenital heart defects were studied. Patients were premedicated with oral or rectal pentobarbitone 2 mg.kg-1 90 minutes prior to induction of anaesthesia followed by intramuscular morphine 0.2 mg.kg-1 and atropine 0.02 mg.kg-1 60 minutes prior to induction. The SaO2 and HR of each child were monitored continuously using a Nellcor pulse oximeter during two 90 minute periods: a control period commencing 25.5 hours preoperatively (day 1) and a post premedication period commencing 1.5 hours preoperatively (day 2). Data were compared at time 0 (corresponding to the time of administration of pentobarbitone on day 2), 30 (corresponding to the administration of intramuscular morphine and atropine on day 2), 60 and 90 minutes (the latter corresponding to the time of induction on day 2) after the administration of pentobarbitone. There were no significant differences in SaO2 or HR between day 1 and day 2 at time 0, 60, and 90 minutes. The SaO2 (mean +/- SD) decreased significantly immediately following intramuscular premedication at time 30 minutes on day 2 (72.7 +/- 5.9 per cent) compared to the corresponding time on day 1 (83.9 +/- 2.9 per cent) (p less than 0.05). The duration of this desaturation was 2.5 +/- 1.9 minutes. Heart rate (mean +/- SD) increased from 109.2 +/- 21.3 beats.min-1 at time 30 minutes on day 1 to 142 +/- 20.4 beats.min-1 on day 2 (p less than 0.05). We conclude that administration of intramuscular premedication preceded by oral or rectal pentobarbitone causes transient arterial desaturation and tachycardia in children with cyanotic congenital heart disease.

Child↗
PubMed1988

Anterior fontanelle pressure responses to tracheal intubation in the awake and anaesthetized infant.

In order to define the changes in intracranial pressure which occur during tracheal intubation in young infants, a Ladd transducer was used to monitor anterior fontanelle pressure (AFP) non-invasively in awake (group 1, n = 14) and anaesthetized (group 2, n = 10) infants during intubation of the trachea. Heart rate and systolic arterial pressure were also recorded. In quiet, undisturbed infants, AFP (mean +/- SEM) was similar in groups 1 (9.6 +/- 0.5 mm Hg) and 2 (8.7 +/- 0.8 mm Hg); with crying, AFP increased significantly in both groups. During laryngoscopy in group 1, AFP increased to 33.5 +/- 3.6 mm Hg, which was significantly greater than in the quiet infant, but did not differ significantly from measurements in the crying infant. In group 2, AFP increased significantly to 15.8 +/- 18 mm Hg during laryngoscopy. This increase was significantly less than the group 1 response. Neither heart rate nor systolic arterial pressure changed significantly in either group during laryngoscopy--when compared with measurements in the quiet state. It was concluded that AFP increases significantly during intubation and during crying in the infant. The response to intubation is only partially attenuated by the prior administration of general anaesthesia.

Anesthesia, General↗
PubMed1988

Plasma bupivacaine concentrations during caudal analgesia and ilioinguinal-iliohypogastric nerve block in children.

Plasma bupivacaine concentrations were measured in 27 children aged 3-7 years who received one of two analgesic regimens for herniotomy or orchidopexy. Analgesia was provided either by caudal epidural bupivacaine 0.2% 2 mg/kg (n = 14) or by ilioinguinal-iliohypogastric nerve block with bupivacaine 0.5% 1.25 mg/kg (n = 13). Mean (SD) peak venous bupivacaine concentrations were 0.57 (0.17) microgram/ml and 0.79 (0.38) microgram/ml respectively. Time to peak plasma concentrations were 29.6 (7.9) and 22.3 (10.9) minutes respectively. These concentrations are well below the potentially toxic level of 4.0 micrograms/ml, but suggest that uptake of bupivacaine is more rapid after ilioinguinal-iliohypogastric nerve block than during caudal analgesia.

Anesthesia, Caudal↗
PubMed1987

The effects of cardiopulmonary bypass and profound hypothermic circulatory arrest on anterior fontanel pressure in infants.

The Ladd transducer was used to measure anterior fontanel pressure in 23 infants undergoing cardiopulmonary bypass and profound hypothermic circulatory arrest for surgical correction of congenital heart disease. Mean (+/- SD) minimum oesophageal and rectal temperatures of 11.3 +/- 1.5 degrees C and 18.1 +/- 2.2 degrees C respectively were achieved with a mean duration of arrest of 53.4 +/- 13.9 minutes. During reperfusion cardiopulmonary bypass after circulatory arrest, mean anterior fontanel pressure (18.3 +/- 6.4 mmHg) increased above baseline pre-bypass values (10.6 +/- 2.9 mmHg) (p less than 0.005). Mean arterial blood pressure decreased significantly from pre-bypass values (57.0 +/- 11.8 mmHg) during both cooling (38.8 +/- 8.4 mmHg) and rewarming cardiopulmonary bypass (45.8 +/- 8.9 mmHg) (p less than 0.005). These changes were associated with a significant decrease in cerebral perfusion pressure during cooling (27.3 +/- 11.0 mmHg) and rewarming cardiopulmonary bypass (27.5 +/- 10.6 mmHg), compared with baseline pre-bypass values (46.5 +/- 12.3 mmHg) (p less than 0.005). The data demonstrate significant but transient decreases in cerebral perfusion pressure during cooling and rewarming bypass.

Cardiopulmonary Bypass↗
PubMed1987

Anaesthesia for paediatric tonsillectomy. Comparison of spontaneous ventilation and intermittent positive pressure ventilation.

Fifty children undergoing tonsillectomy were anaesthetized using either a spontaneous ventilation (SV) technique with halothane (and nitrous oxide in oxygen) or intermittent positive pressure ventilation (IPPV) (with nitrous oxide, in oxygen) facilitated by atracurium 0.5 mg kg-1. Time to full recovery was significantly less in the IPPV group (1.8 +/- 3.79 min) than the SV group (20.0 +/- 6.77 min) (P less than 0.001) and ventilated children had a better quality of long-term recovery (sleep score 1.02 for the SV and 1.44 for the IPPV groups) (P less than 0.01). Apart from a significantly greater E'CO2 in the halothane group (7.3 kPa +/- 0.9 compared with 5.1 kPa +/- 0.5) (P less than 0.001), there was no significant difference in operative or postoperative morbidity.

Anesthesia Recovery Period↗