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Biomedical subjects

S M Kinsella

Publications and source records attributed to S M Kinsella.

At least 19 recordsLinked to original sources
PubMed2006

Effect of blood pressure instrument and cuff side on blood pressure reading in pregnant women in the lateral recumbent position.

BACKGROUND: Hydrostatic forces affect non-invasive blood pressure measurement in the lateral position. This study assessed the extent of this effect with the mercury column sphygmomanometer and Dinamap oscillometric instrument as well as different recommendations for comparing supine and lateral blood pressure measurements. METHOD: Thirty-two term pregnant women were studied in the antenatal clinic. Blood pressure was recorded from both arms in the right lateral and supine recumbent positions, using the sphygmomanometer and Dinamap. RESULTS: Blood pressure in the uppermost arm while lateral was lower than supine by a mean 10 mmHg or more. Systolic, mean and diastolic pressures in the dependent arm while lateral were higher than supine by a mean (SD) 3.1 (6.8)mmHg, 5.6 (6.8)mmHg, and 6.9 (8.7)mmHg using the sphygmomanometer and 3.8 (8.1)mmHg, 3.2 (7.1)mmHg, and 1.9 (5.3)mmHg using the Dinamap. Systolic, mean and diastolic pressure values calculated as the average taken from both arms in the lateral position were lower than supine by a mean (SD) 3.5 (7.5)mmHg, 3.9 (4.7) mmHg, and 4.1 (5.8)mmHg using the sphygmomanometer and 4.6 (6.0)mmHg, 4.9 (4.4)mmHg, and 4.8 (4.4)mmHg using the Dinamap. Corresponding blood pressure readings were always higher using the Dinamap than the sphygmomanometer. CONCLUSIONS: In normotensive non-labouring term pregnant women, the use of the dependent arm or an average blood pressure from both arms while in the lateral position will give a closer reading to supine blood pressure than the use of the uppermost arm. However, use of the dependent arm is simpler.

Adult↗
PubMed2006

Propofol and memory.

Explore the source record for details and available documents.

Anesthetics, Intravenous↗
PubMed2005

Obstetric epidural test doses: a survey of UK practice.

BACKGROUND: With the advent of low-dose epidural analgesia in labour, the content of the test dose has once again become the subject of debate. METHOD: A postal survey of 500 members of the Obstetric Anaesthetists' Association was conducted in 1999-2000, assessing the use of test doses during epidurals in labour and for caesarean section. RESULTS: There was a 67% response rate. Test doses are used in labour, at elective caesarean section and before epidural top-up for emergency caesarean section, by 90%, 93% and 37%, respectively. There was large variation in both drugs and doses. During labour, doses of bupivacaine range from 3 to 20 mg and of lidocaine 15 to 90 mg. There has been a three-fold increase in the use of low-dose local anaesthetic test doses since a previous national survey in 1997. The size of local anaesthetic test doses used at caesarean section is also variable. Epinephrine is used in 5% of labour, 14% of elective and 34% of emergency caesarean sections. Signs and symptoms that are commonly sought after test doses include somatic motor block, blood pressure change, sensory effect and symptoms from systemic local anaesthetic. The effect of the test dose is usually assessed after 5 min. CONCLUSION: There is no consensus about the nature of the ideal test dose in obstetric anaesthesia. There is a trend to use less concentrated test doses during labour. Doses that risk a high block if given spinally are still used. Epinephrine, aspiration testing and cardiovascular monitoring are uncommon.

Analgesia, Epidural↗
PubMed2003

100% inspired oxygen from a Hudson mask-a realistic goal?

BACKGROUND: The administration of oxygen at a high-inspired concentration is often required in medicine, particularly in resuscitation of critically ill patients. However, there is a lack of evidence-based guidance on how to achieve this using currently available apparatus. The aim of this study was to assess how maximum inspired oxygen concentrations can be delivered using existing equipment. METHODS: Ten healthy female volunteers breathed oxygen through two types of Hudson non-rebreathing mask with reservoir bag, one with a safety vent in the mask body and the other with a valve replacing this safety vent (3-valve mask). Oxygen flow was adjusted to either 10 or 15 l min(-1) and the masks were fitted to the face either loosely or tightly. The expired oxygen concentration was measured using an oxygen analyzer. FINDINGS: By using the Hudson non-rebreathing mask with three valves, increasing the oxygen flow to 15 l min(-1), and fitting the mask tightly to the face the average expired oxygen fraction could be raised to 0.85. This equates to an average inspired oxygen fraction of 0.97 in these subjects. INTERPRETATION: The three simple measures mentioned above result in a significant improvement in the performance of the Hudson non-rebreathing mask. Together they allow the delivery of an inspired oxygen concentration close to maximum.

Adult↗
PubMed2003

Comparison of measured and estimated angles of table tilt at Caesarean section.

BACKGROUND: Lateral maternal tilt reduces aortocaval compression and the consequent cardiovascular instability. METHODS: We measured the angle of table tilt used by 16 anaesthetists during uncomplicated, elective Caesarean section. After initiating anaesthesia, they were asked to position the patient and estimate the angle of tilt, which was then measured. RESULTS: Almost every anaesthetist positioned the patient less than 15 degrees because they overestimated the angle of tilt. When questioned on their knowledge of the current advice for lateral tilt, 11 of the 16 anaesthetists were aware of the 15 degrees recommendation. CONCLUSION: Estimation of the angle of table tilt is unreliable.

Anesthesia, Obstetrical↗
PubMed2002

Maternal cardiovascular consequences of positioning after spinal anaesthesia for Caesarean section: left 15 degree table tilt vs. left lateral.

Sixty healthy women undergoing elective Caesarean section were randomly allocated to either a measured 15 degrees left table tilt position (n = 31) or full left lateral position (n = 29) for a 15-min period after spinal blockade. Arm and leg blood pressure, ephedrine requirements, symptoms, fetal heart rate, cord gases and Apgar scores were recorded. Mean ephedrine requirements and incidence of hypotension were similar in the two groups. Arm systolic arterial pressure over time was similar in both groups, but leg systolic arterial pressure over time was significantly lower in the tilt group (p < 0.001); the mean leg systolic arterial pressure was lower for all 15 sequential recordings in the tilt group, reaching statistical significance (p < 0.05) at 4, 5, 6 and 8 min. Differences in maternal nausea, vomiting and bradycardia and fetal outcome were not statistically significant. Following spinal anaesthesia, even a true 15 degrees left table tilt position is associated with aortic compression.

Adult↗
PubMed2002

Intrauterine resuscitation: active management of fetal distress.

Acute fetal distress in labour is a condition of progressive fetal asphyxia with hypoxia and acidosis. It is usually diagnosed by finding characteristic features in the fetal heart rate pattern, wherever possible supported by fetal scalp pH measurement. Intrauterine resuscitation consists of applying specific measures with the aim of increasing oxygen delivery to the placenta and umbilical blood flow, in order to reverse hypoxia and acidosis. These measures include initial left lateral recumbent positioning followed by right lateral or knee-elbow if necessary, rapid intravenous infusion of a litre of non-glucose crystalloid, maternal oxygen administration at the highest practical inspired percentage, inhibition of uterine contractions usually with subcutaneous or intravenous terbutaline 250 microg, and intra-amniotic infusion of warmed crystalloid solution. Specific manoeuvres for umbilical cord prolapse are also described. Intrauterine resuscitation may be used as part of the obstetric management of labour, while preparing for caesarean delivery for fetal distress, or at the time of establishment of regional analgesia during labour in the compromised fetus. The principles may also be applied during inter-hospital transfers of sick or labouring parturients.

Journal Article↗
PubMed2001

Performance of standard and reservoir-type Hudson masks in pregnant and non-pregnant subjects.

We have assessed the performance of the Hudson-type mask without reservoir and the Hudson non-rebreathing mask with reservoir bag in 10 pregnant and 10 non-pregnant women at different oxygen flow rates by measuring end-expired oxygen fraction (FEO(2)). The Hudson mask without reservoir behaved similarly in pregnant and non-pregnant women, providing a mean FEO(2) of 0.32 with oxygen flow of 4 L.min(-1) which increased to 0.46 at 15 L.min(-1). The reservoir mask produced a lower FEO(2) in pregnant subjects than in non-pregnant subjects, with a mean FEO(2) of 0.33 and 0.64 at 4 L.min(-1) and 15 L.min(-1) in pregnant subjects compared to 0.44 and 0.72, respectively, in non-pregnant women. Neither mask delivers the expected maximum inspired oxygen fraction quoted by its manufacturer, assuming that inspired oxygen fraction quoted by its manufacturer, assuming that inspired oxygen fraction is 0.06 higher than expired and correcting for humidification of inhaled gases within the respiratory tract. The importance of these findings in the care of the obstetric patient and the treatment of acute fetal hypoxia is discussed.

Journal Article↗
PubMed2001

Perioperative bradycardia and asystole: relationship to vasovagal syncope and the Bezold-Jarisch reflex.

Reflex cardiovascular depression with vasodilation and bradycardia has been variously termed vasovagal syncope, the Bezold-Jarisch reflex and neurocardiogenic syncope. The circulatory response changes from the normal maintenance of arterial pressure, to parasympathetic activation and sympathetic inhibition, causing hypotension. This change is triggered by reduced cardiac venous return as well as through affective mechanisms such as pain or fear. It is probably mediated in part via afferent nerves from the heart, but also by various non-cardiac baroreceptors which may become paradoxically active. This response may occur during regional anaesthesia, haemorrhage or supine inferior vena cava compression in pregnancy; these factors are additive when combined. In these circumstances hypotension may be more severe than that caused by bradycardia alone, because of unappreciated vasodilation. Treatment includes the restoration of venous return and correction of absolute blood volume deficits. Ephedrine is the most logical choice of single drug to correct the changes because of its combined action on the heart and peripheral blood vessels. Epinephrine must be used early in established cardiac arrest, especially after high regional anaesthesia.

Afferent Pathways↗
PubMed2000

Placental oxygen transfer and intrauterine resuscitation: a survey of knowledge in maternity care professionals.

We surveyed 99 maternity care professionals (obstetricians, midwives and anaesthetists in equal numbers) to assess their knowledge of potential treatments during acute intrapartum fetal hypoxia, including maternal oxygen administration. Knowledge of adult arterial oxygen saturation was satisfactory, but few of those surveyed gave a correct figure for fetal oxygenation in terms of umbilical vein oxygen saturation. Only 58% said that maternal oxygen inhalation would affect fetal oxygenation, and 76% of those giving a figure underestimated the potential extent of the increase. Other aspects of intrauterine resuscitation were also not identified. Out of three further factors besides maternal oxygen administration which are commonly considered, 76% suggested none or one, and only 24% noted two or all three. Acute fetal hypoxia during labour and delivery may be amenable to correction by improving oxygen supply to the placenta. We identified deficits in the underlying knowledge of these processes among maternity care professionals. Without this knowledge, correctable causes of fetal hypoxia may go untreated.

Journal Article↗
PubMed2000

Low dose combined spinal-epidural anaesthesia for caesarean section in a patient with peripartum cardiomyopathy.

A patient with peripartum cardiomyopathy was scheduled for elective caesarean section after stabilization on medical therapy. Wer performed a combined spinal epidural using one ml 0.5% hyperbaric bupivacaine (5 mg) with 0.3 mg diamorphine for the spinal. The epidural was topped up with 10 mL bupivacaine 0.5%. Significant haemodynamic changes consisted of reduction in heart rate and hypotension after the spinal, and tachycardia after delivery. The benefits and risks of this approach are discussed.

Journal Article↗