Caffeine pharmacokinetics following umbilical vein injection during delayed cord clamping in preterm lambs

BACKGROUND

Spontaneous breathing during and after delayed cord clamping (DCC) stabilizes cardiopulmonary transition at birth. Caffeine stimulates breathing and decreases apnea in premature newborns. We evaluated the pharmacokinetics and physiological effects of early caffeine administration-direct injection into the umbilical vein (UV) during DCC or administered through a UV catheter (UVC) after delivery.

METHODS

Eighteen extremely premature lambs (125-127d, term gestation 145d) were exteriorized and instrumented. Lambs received caffeine-citrate at high (40 mg/kg) or standard-dose (20 mg/kg) via direct UV (DUV) injection during DCC, or via the UVC.

RESULTS

Mean peak plasma caffeine concentrations were lower with high-dose DUV compared to UVC (18 ± 4.3 vs. 46 ± 12 mg/L, p < 0.05). With standard-dose caffeine, mean peak plasma levels were 7.48 ± 2.6 with DUV and 28.73 ± 9.4 mg/L with UVC. The volume of distribution was higher in the DUV group compared to UVC (2.5 ± 1.0 vs. 0.69 ± 0.15 L/kg) with an estimated 39 ± 18% entering the maternal circulation. Maternal peak concentrations were 0.79 ± 0.71 and 1.43 ± 0.74 mg/L with standard and high-dose DUV, respectively.

CONCLUSIONS

Caffeine injected directly into the UV during DCC is feasible but achieves lower concentrations due to high volume of distribution including maternal circulation. Further trials evaluating DUV caffeine injection should use higher caffeine doses.

IMPACT

Respiratory stimulation with early caffeine may reduce the need for intubation in preterm infants. In the preterm lambs, caffeine injection directly into the umbilical vein during delayed cord clamping is feasible. Plasma caffeine concentrations are less than half when administered directly into the umbilical vein during delayed cord clamping compared to administration via an umbilical venous catheter following birth likely attributed to a larger volume of distribution or injection site leak. There were no significant hemodynamic alterations following caffeine injection.

Neonatal resuscitation with continuous chest compressions and high frequency percussive ventilation in preterm lambs

BACKGROUND

Cerebral oxygen delivery (cDO2) is low during chest compressions (CC). We hypothesized that gas exchange and cDO2 are better with continuous CC with high frequency percussive ventilation (CCC + HFPV) compared to conventional 3:1 compressions-to-ventilation (C:V) resuscitation during neonatal resuscitation in preterm lambs with cardiac arrest induced by umbilical cord compression.

METHODS

Fourteen lambs in cardiac arrest were randomized to 3:1 C:V resuscitation (90CC + 30 breaths/min) per the Neonatal Resuscitation Program guidelines or CCC + HFPV (120CC + HFPV continuously). Intravenous epinephrine was given every 3 min until return of spontaneous circulation (ROSC).

RESULTS

There was no difference in the incidence and time to ROSC between both groups. Median (IQR) PaCO2 was significantly lower with CCC + HFPV during CC, at ROSC and 15 min post-ROSC-[104 (99-112), 83 (77-99), and 43 (40-64)], respectively compared to 3:1 C:V-[149 (139-167), 153 (143-168), and 153 (138-178) mmHg. PaO2 and cDO2 were higher with CCC + HFPV during CC and at ROSC. PaO2 was similar 15 min post-ROSC with a lower FiO2 in the CCC + HFPV group 0.4 (0.4-0.5) vs. 1 (0.6-1).

CONCLUSION

In preterm lambs with perinatal cardiac-arrest, continuous chest compressions with HFPV does not improve ROSC but enhances gas exchange and increases cerebral oxygen delivery compared to 3:1 C:V during neonatal resuscitation.

IMPACT STATEMENT

Ventilation is the most important intervention in newborn resuscitation. Currently recommended 3:1 compression-to-ventilation ratio is associated with hypercarbia and poor oxygen delivery to the brain. Providing uninterrupted continuous chest compressions during high frequency percussive ventilation is feasible in a lamb model of perinatal cardiac arrest, and demonstrates improved gas exchange and oxygen delivery to the brain. This is the first study in premature lambs evaluating high frequency percussive ventilation with asynchronous chest compressions and lays the groundwork for future clinical studies to optimize gas exchange and hemodynamics during chest compressions in newborns.

Continuous chest compressions with asynchronous ventilations increase carotid blood flow in the perinatal asphyxiated lamb model

BACKGROUND

The neonatal resuscitation program (NRP) recommends interrupted chest compressions (CCs) with ventilation in the severely bradycardic neonate. The conventional 3:1 compression-to-ventilation (C:V) resuscitation provides 90 CCs/min, significantly lower than the intrinsic newborn heart rate (120-160 beats/min). Continuous CC with asynchronous ventilation (CCCaV) may improve the success of return of spontaneous circulation (ROSC).

METHODS

Twenty-two near-term fetal lambs were randomized to interrupted 3:1 C:V (90 CCs + 30 breaths/min) or CCCaV (120 CCs + 30 breaths/min). Asphyxiation was induced by cord occlusion. After 5 min of asystole, resuscitation began following NRP guidelines. The first dose of epinephrine was given at 6 min. Invasive arterial blood pressure and left carotid blood flow were continuously measured. Serial arterial blood gases were collected.

RESULTS

Baseline characteristics between groups were similar. Rate of and time to ROSC was similar between groups. CCCaV was associated with a higher PaO₂ (partial oxygen tension) (22 ± 5.3 vs. 15 ± 3.5 mmHg, p < 0.01), greater left carotid blood flow (7.5 ± 3.1 vs. 4.3 ± 2.6 mL/kg/min, p < 0.01) and oxygen delivery (0.40 ± 0.15 vs. 0.13 ± 0.07 mL O₂/kg/min, p < 0.01) compared to 3:1 C:V.

CONCLUSIONS

In a perinatal asphyxiated cardiac arrest lamb model, CCCaV showed greater carotid blood flow and cerebral oxygen delivery compared to 3:1 C:V resuscitation.

IMPACT

In a perinatal asphyxiated cardiac arrest lamb model, CCCaV improved carotid blood flow and oxygen delivery to the brain compared to the conventional 3:1 C:V resuscitation. Pre-clinical studies assessing neurodevelopmental outcomes and tissue injury comparing continuous uninterrupted chest compressions to the current recommended 3:1 C:V during newborn resuscitation are warranted prior to clinical trials.

A phase 1, pharmacokinetic (PK) and pharmacodynamic (PD) study of CHIR-258, a novel oral multiple receptor tyrosine kinase (RTK) inhibitor

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Background: CHIR-258 is a potent small molecule inhibitor of VEGF, FGF, PDGF and c-KIT RTKs with IC50≤10nM that demonstrates activity in a variety of angiogenesis, tumour and metastasis models. Methods: Patients (pts) with histologically confirmed advanced solid tumors, ECOG PS 0–2 were treated in cohorts of 3–6 with CHIR-258. Treatment was as single daily doses on a repeated 7 days (d) on/7d off schedule (25–100mg), with a subsequent protocol amendment to continuous (cont) daily dosing. The objectives were to determine maximum tolerated dose (MTD) and dose limiting toxicity (DLT), evaluate PK and PD endpoints - ERK phosphorylation in PBL - and describe anti-tumour activity. Results: 35pts (median age 56.5 yrs; 15F/20M) were treated in 4 intermittent dosing cohorts (25, 50, 75, 100 mg/d) and 3 continuous dosing cohorts (100,125, 175 mg/d). The most common drug related adverse events were (grade [gr], number of pts): nausea (gr 1–3, 12); fatigue (gr 1–2, 9); headache (gr 1–3, 8); vomiting (gr 1–2, 7); anorexia (gr 1–2, 7); diarrhoea (gr 1–2, 6); dysgeusia (gr1–2, 6); anaemia (gr 2–3, 4); hypertension (gr 1–3, 3) and reversible asymptomatic drop in left ventricular ejection fraction (gr 2, 2). DLTs were gr 3 hypertension (HTN) in 1 pt with pre-existing HTN (100mg, cont); asymptomatic uncomplicated grade 2 elevation in cardiac troponin I (125mg); gr 3 anorexia/fatigue and gr 3 rise in alkaline phosphatase (both at 175mg). 3 pts have had prolonged stable disease (all 4m+; parotid, renal and imatinib-refractory GIST). The plasma PKs of CHIR-258 were linear over the dose range of 25–175 mg with respect to Cmax and AUC. On d1, the mean Cmax was 13.5(5.3) ng/mL to 109 (26) ng/mL, the mean AUC (0–24) was 224(97.4)ng*h/mL to 1740(466)ng*h/mL, and the t½ was 17h. Trough CHIR-258 concentrations at doses >50 mg/d were above the concentrations known to inhibit target receptor activation in vitro. Data on evaluable samples demonstrate up to 90% inhibition of basal ERK phosphorylation. Conclusions: CHIR-258 was safely administered at continuous daily doses up to 175mg/d. Modulation of p-ERK was demonstrated. Treatment is associated with disease stabilization.

[Table: see text]

Operative morbidity and reproductive outcome in secondary myomectomy: a prospective cohort study

BACKGROUND

This prospective study was designed to evaluate the operative morbidity and reproductive outcome in patients who had secondary myomectomy for recurrent symptomatic uterine fibroids.

METHODS

A total of 58 women were subjected to a secondary myomectomy via the abdominal route. The operative morbidity such as blood loss, presence of adhesions and febrile index were estimated and the pregnancy outcome over a 2-4 year period of follow-up.

RESULTS

The mean age and standard deviation (+/- SD) of the women was 35 (+/- 2.4) years. Nineteen patients (33%) had a postoperative temperature vertical line 100 degrees F and the estimated blood loss ranged from 159-2500 ml (median 700 ml). Seven patients (12%) required blood transfusion and one had a hysterectomy due to haemorrhage. Nine women (15.5%) became pregnant but only five (56%) had live births. Those with successful pregnancies tended to be younger with a mean age of 31.8 (+/- 2.6) years versus 35 (+/- 1.8) years, (P = 0.08, non-significant) and had fewer uterine leiomyomata; median with range values, 2 (1-6) versus 7 (6-15). The variables which best predicted the postoperative likelihood of pregnancy were; age, presence of tubal adhesions and the number of uterine fibroids.

CONCLUSION

This prospective study showed a high operative morbidity and a poor fertility outcome after a repeat myomectomy. The factors affecting successful outcome in a logistic regression model were age, tubal adhesions and number of uterine fibroids.

A randomized comparison of vasopressin and tourniquet as hemostatic agents during myomectomy

OBJECTIVE

To assess the comparative efficacy of perivascular vasopressin and tourniquet in minimizing bleeding and its sequelae at myomectomy.

METHODS

Between March 1994 and February 1995, 52 women with symptomatic uterine leiomyomas scheduled for myomectomy were entered into a randomized trial comparing vasopressin (26 patients) and tourniquet (26 patients) for hemostasis. Myomectomy was performed after either the perivascular injection of 20 U of vasopressin diluted to 20 mL with normal saline or with the use of a Foley catheter tourniquet around both uterine vessels. The efficacy of each method was measured by comparing differences in pre- and postoperative hemoglobin levels, intraoperative blood pressure, measured blood loss, need for blood transfusion, evidence of postoperative febrile morbidity, complications, and length of hospital stay.

RESULTS

Vasopressin resulted in less blood loss (mean 287.3 mL [standard deviation (SD) 195] versus 512.7 mL [SD 400] for tourniquet [P = .036]). Six of 26 patients in the tourniquet group lost more than 1000 mL of blood, whereas all of the vasopressin subjects lost less than this amount (P = .023). However, there were no significant differences between the two groups in the fall in the hemoglobin level, number of blood transfusions given, intraoperative blood pressure, highest postoperative pulse and temperature, or other complications.

CONCLUSION

Vasopressin prevents blood loss better than using the tourniquet during myomectomy.

Intramyometrial vasopressin as a haemostatic agent during myomectomy

OBJECTIVE

To assess the efficacy of intramyometrial vasopressin for minimising bleeding and its sequelae at myomectomy.

DESIGN

A randomised placebo controlled trial.

SETTING

University Hospital of the West Indies, Kingston, Jamaica.

SUBJECTS

Twenty women with symptomatic uterine fibroids scheduled for myomectomy who satisfied entry criteria: 10 randomised to the vasopressin group and 10 to the control group.

INTERVENTION

Myomectomy was performed after the intramyometrial injection of either 20 units vasopressin diluted to 20 ml in normal saline or placebo (20 ml normal saline).

MAIN OUTCOME MEASURES

The efficacy of vasopressin was measured by comparing pre- and post-operative haemoglobin levels and haematocrit, changes in intra-operative pulse and blood pressure, measured blood loss, need for blood transfusion and post-operative febrile morbidity in the treatment and control groups.

RESULTS

The use of vasopressin resulted in median blood loss of 225 ml (range 150-400 ml) compared with 675 ml (range 500-800 ml) in the placebo group (P < 0.001). The vasopressin group had a correspondingly lower fall in haemoglobin level (median 1.7 g/dl vs 5.3 g/dl, P < 0.001) and haematocrit (median 5% vs 13%, P < 0.001) compared with the controls. Fifty percent of the placebo group had blood transfusions compared with none in the vasopressin group (P = 0.03). There were no significant differences between the groups in intra-operative pulse and blood pressure or post-operative white blood cell counts or temperature.

CONCLUSION

The results indicate that vasopressin is effective in preventing blood loss and reducing the need for blood transfusion during myomectomy.

Preeclampsia in diabetic pregnancies

Diabetic pregnancies complicated by preeclampsia are of concern because of poor perinatal outcome. However, with improved maternal and fetal surveillance the impact of preeclampsia in diabetic pregnancies is declining. This prospective controlled study compared the incidence of preeclampsia and maternal-fetal outcome in 334 diabetic pregnancies and 16,534 nondiabetic pregnancies. The incidence of preeclampsia was 9.9% (33/334) in diabetic pregnancies compared with 4.3% (716/16,534) in nondiabetic controls. The incidence of preeclampsia rose with increasing severity of diabetes by White classification, but was still 8.9% after exclusion of diabetic patients with nephropathy or chronic hypertension. The perinatal mortality rate per 1000 births was 60 for preeclamptic diabetic patients compared with 3.3 for normotensive diabetic patients. Parity, maternal age, and blood glucose control were similar in preeclamptic diabetic patients compared with normotensive diabetic patients. We conclude that preeclampsia is twice as common in diabetic pregnancies compared with normal controls.

World health: grappling with big-city problems

London's big-city health problems are shared by 26 other cities of similar size throughout the world. By the year 2000 there will be many more of them. Miles Hardie, director-general of the International Hospital Federation, reflects on a recent UNFPA conference.