Cardiac output changes with phenylephrine and ephedrine infusions during spinal anesthesia for cesarean section: A randomized, double-blind trial.

Hypotension is a common side effect of spinal anesthesia. Phenylephrine and ephedrine are the two most frequently used vasopressors to treat spinal hypotension during cesarean delivery. In this randomized double-blind study, we aimed to evaluate cardiac output (CO) changes with phenylephrine or ephedrine infusions titrated to maintain baseline systolic blood pressure (bSBP) during spinal anesthesia. Women (n = 40) scheduled for elective cesarean delivery received either phenylephrine 100 µg/min or ephedrine 5 mg/min infusions. Baseline hemodynamics (cardiac output, heart rate, systolic blood pressure) were recorded in the left lateral tilt position before fluid preload, and recorded every minute after spinal anesthesia until delivery. Umbilical cord blood gases were analyzed within 5 minutes of delivery. Good systolic blood pressure control was attained in both groups with minimal periods of hypotension (SBP <80% of bSBP) or hypertension (SBP >120% of bSBP). Cardiac output and heart rate increased over time with ephedrine, but decreased with phenylephrine. The maximum increase in CO from the baseline was 12%, in the ephedrine group, and this occurred 20 minutes after spinal injection. Cardiac output fell by more than 17% in the phenylephrine group, maximal at 10 minutes following spinal injection. Despite good systolic blood pressure control and increased cardiac output with ephedrine, administration of ephedrine was associated with significantly more fetal acidosis [Median (Interquartile range, IQR) UApH - phenylephrine = 7.33 (7.31-7.34) and ephedrine = 7.22 (7.16-7.27), P < .05].

Reference ranges for thromboelastography (TEG(®) ) and traditional coagulation tests in term parturients undergoing caesarean section under spinal anaesthesia*.

There has been little published work defining 'normal' thromboelastography (TEG(®) ) values in healthy parturients, and few large studies defining reference ranges for traditional coagulation tests in this patient group. Our aim was to establish peri-operative reference ranges for TEG and for standard laboratory coagulation tests in our pregnant population. Fifty healthy term parturients presenting for elective caesarean section under spinal anaesthesia had blood samples taken pre-operatively, on arrival in the recovery room and, in a subset of 33 women, 4 h after routine thromboprophylaxis with enoxaparin 40 mg. All three samples had TEG analysis, the first and second having standard laboratory coagulation tests in addition. Reference ranges for our pregnant population were established, demonstrating a hypercoagulable state in term parturients and a significant effect of enoxaparin. The standard coagulation reference ranges were within 98% of the local non-pregnant ranges. These reference ranges provide a useful comparator for peri-operative TEG and routine coagulation analysis in term parturients.

Assessment of coagulation in the obstetric population using ROTEM® thromboelastometry.

BACKGROUND: Assessment of maternal coagulation to determine suitability for neuraxial anaesthesia and management of obstetric haemorrhage remains a challenge. Thromboelastography provides point of care patient assessment of the viscoelastic properties of whole blood clotting and can assist the clinician in haemostatic decision-making. The study aim was to determine the ROTEM® thromboelastometer 95% reference limits for third trimester parturients and to compare these with non-pregnant female controls. METHODS: Following ethics committee approval and informed consent, citrated blood was sampled from 120 age-matched healthy pregnant and non-pregnant women. Thromboelastometry, using a ROTEM® point of care monitor, was performed with specific activators to measure the coagulation time (CT), clot formation time (CFT) and the maximal clot firmness (MCF) in order to evaluate the extrinsic (EXTEM® test) and intrinsic (INTEM® test) coagulation systems, as well as the fibrinogen contribution to coagulation (FIBTEM® test). RESULTS: After exclusions, data from 54 subjects in each group were analysed. Parturients had significantly lower haemoglobin values and platelet counts (P<0.01). Despite this, thromboelastometry exhibited significantly lower INTEM® CT (7.3%), INTEM® CFT (11.1%) and EXTEM® CFT (18.0%) in the pregnant group (P<0.001). MCF values were significantly higher (INTEM® (10.9%), EXTEM® (10.6%) and FIBTEM® (47.1%)) in the pregnant group compared to the non-pregnant group (P<0.0001). CONCLUSIONS: ROTEM® thromboelastometry clearly demonstrates the hypercoagulability of pregnancy. Formal reference ranges for ROTEM® that may be potentially useful in the haemostatic management of the parturient are presented.

Peripartum cardiac chest pain and troponin rise.

The incidence of myocardial ischaemia is increasing in the obstetric population. This has been attributed to several factors including greater maternal age, the increasing incidence of obesity and diabetes, and the growing population of patients with grown-up congenital heart disease who now reach adulthood and become pregnant. A number of cases of myocardial ischaemia in pregnant women have been documented, during and after delivery, for which no cause has been established. We present a case of a nulliparous woman who developed cardiac chest pain, bradycardia, hypertension and a raised troponin I after vaginal delivery of twin boys at 36 weeks of gestation. Ischaemic electrocardiogram changes were noted. Detailed investigations demonstrated a normal coronary circulation. A patent foramen ovale was found on bubble echocardiography.

Litigation related to regional anaesthesia: an analysis of claims against the NHS in England 1995-2007.

We analysed 366 claims related to regional anaesthesia and analgesia from the 841 anaesthesia-related claims handled by the National Health Service Litigation Authority between 1995 and 2007. The majority of claims (281/366, 77%) were closed at the time of analysis. The total cost of closed claims was pound12,724,017 (34% of the cost of the anaesthesia dataset) with a median (IQR [range]) of pound4772 (pound0-28,907 [pound0-2,070,092]). Approximately half of the claims (186/366; 51%) were related to obstetric anaesthesia and analgesia and of the non-obstetric claims, the majority (148/180; 82%) were related to neuraxial block. The total cost for obstetric closed claims was pound5,433,920 (median (IQR [range]) pound5678 (pound0-27,690 [pound0-1,597,565]) while that for non-obstetric closed claims was pound7,290,097 (pound3337 (pound0-31,405 [pound0-2,070,062]). Non-obstetric claims were more likely to relate to severe outcomes than obstetric ones. The maximum values of claims were higher for claims related to neuraxial blocks and eye blocks than for peripheral nerve blocks. Despite many limitations, including lack of clinical detail for each case, the dataset provides a useful overview of the extent, patterns and cost associated with the claims.

The TEG vs the ROTEM thromboelastography/thromboelastometry systems.

We have evaluated the TEG thromboelastograph and the ROTEM thromboelastometer, two point-of-care devices that measure blood coagulation. During a one-week period, seven consultant anaesthetists, one consultant haematologist, one associate specialist anaesthetist and two senior trainee anaesthetists were trained by the manufacturers and set up, calibrated and used both systems, after which their views were obtained and specific technical/support information was sought from the manufacturers using a questionnaire. Although the devices shared common features, they differed in complexity and aspects of ease of use, and in their purchase and running costs.

Remifentanil sedation for awake fibreoptic intubation with limited application of local anaesthetic in patients for elective head and neck surgery.

The aim of this study was to investigate the performance of awake fibreoptic intubation using remifentanil sedation with topical anaesthesia limited only to the nasal mucosa. Twenty-four patients presenting for elective head and neck surgery were sedated using remifentanil titrated to effect and local anaesthetic was applied to the nasal mucosa. Vital signs were recorded throughout the procedure and both the anaesthetist and an observer rated the ease of the procedure. Intubation was successful in all patients and the procedure was rated as easy in 15 (63%) of patients. Mean arterial pressure remained within 8% of baseline in all cases and respiratory rate remained > 8 breaths x min(-1) in all but three patients. Although 56% of patients interviewed postoperatively said they recalled the procedure, all but one would undertake the same procedure again if necessary. This technique appears reliable in providing adequate sedation whilst maintaining cardiovascular and respiratory stability.