Aliya Dabbous

A combination of alfentanil-lidocaine-propofol provides better intubating conditions than fentanyl-lidocaine-propofol in the absence of muscle relaxants

PurposeTo compare the ease of tracheal intubation without the use of muscle reiaxants following an alfentanil-lidocaine-propofol sequence vs a fentanyl-lidocaine-propofol sequence.Clinical featuresIn 80 ASA I and II adult patients undergoing elective laparoscopic surgery, we compared the intubating conditions following alfentanil 20μg· kg−1, lidocaine 1.5 mg· kg−1, propofol 3 mg· kg−1 (Group I;n = 40) vs fentanyl 2 μg· kg−1, lidocaine 1.5 mg· kg−1, propofol 3 mg· kg−1 (Group II;n = 40). The intubating conditions were scored by jaw relaxation, vocal cord position and response to intubation, as well as by blood pressure and heart rate changes. The intubating conditions were good or excellent in 95% of patients in Group I vs 62.5% of patients in Group II (P < 0.05), Blood pressure decreased from a preinduction value of 86 ± 13 mmHg to 72 ± 28 mmHg and 74 ± 19 mmHg in Group I, and from 85 ± 12 mmHg to 78 ± 15 mmHg and 78 ± 12 mmHg in Group II, one and five minutes following intubation (P < 0.05), This drop in blood pressure was not different between the two groups.ConclusionAn alfentanil-lidocaine-propofol sequence offers significantly better intubating conditions than a fentanyl-lidocaine-propofol sequence in healthy adult patients.RésuméObjectifComparer la facilité de l’intubation endotrachéale réalisée, sans recours aux myorelaxants, à la suite de l’administration de la séquence alfentanil-lidocaïne-propofol vs fentanyl-lidocaïne-propofol.Éléments cliniquesNous avons comparé, chez 80 adultes d’état physique ASA I et II devant subir une Intervention laparoscoplque réglée, les conditions d’intubation suivant l’administration de 20 μg· kg−1 d’alfentanil, 1,5 mg· kg−1 de lidocaine et 3 mg· kg−1 de propofol (Groupe I; n = 40) vs 2 μg· kg−1 de fentanyl, 1,5 mg· kg−1 de lidocdïne et 3 mg· kg−1 de propofol (Groupe II; n = 40). Les conditions d’intubation ont été cotées en fonction du relâchement de la mâchoire, de la position des cordes vocales et de la réponse à l’intubation, des changements de tension artérielle et de fréquence cardiaque. Ces conditions ont été bonnes ou excellentes chez 95% des patients du Groupe I vs 62,5 % du Groupe II (P < 0,05). Il y a eu une baisse de la tension artérielle, par rapport aux valeurs enregistrées avant l’induction de 86 ± 13 mmHg à 72 ± 28 mmHg et 74 ± 19 mmHg dans Se Groupe I, et de 85 ± 12 mmHg à 78 ± 15 mmHg à 78 ± 12 mmHg dans le Groupe II, une et cinq minutes après l’Intubation (P < 0,05). Cette chute de la tension artérielle ne présentait pas de différence intergroupe.ConclusionUne séquence d’alfentanll-lidocaïne-propofol offre des conditions slgnificativement meilleures qu’une séquence de fentanyl-lidocaïne-propofol chez des sujets adultes sains.

Lidocaine cardioplegia for prevention of reperfusion ventricular fibrillation

Lidocaine addition to crystalloid cardioplegic solution for prevention of reperfusion ventricular fibrillation after the release of the aortic cross-clamp was studied in 50 patients undergoing coronary artery bypass grafting and in 30 patients undergoing mitral or aortic valve replacement. Twenty-six of the patients undergoing coronary artery bypass grafting received lidocaine, 100 mg/L of cardioplegia, whereas a control group of 24 patients received cardioplegia without lidocaine. In the group undergoing valve replacement, 14 patients received lidocaine cardioplegia and 16 patients served as control. In the coronary artery bypass grafting group, lidocaine cardioplegia reduced significantly the incidence of reperfusion ventricular fibrillation from 100% to 42%. In the valve group, lidocaine cardioplegia also reduced significantly the incidence of reperfusion ventricular fibrillation from 93% to 42%. In both groups, lidocaine cardioplegia decreased the number of direct-current countershocks required to defibrillate the heart, with no significant increase in the incidence of high-grade atrioventricular block.

Effect of alpha-stat versus pH-stat strategy on oxyhemoglobin dissociation and whole-body oxygen consumption during hypothermic cardiopulmonary bypass.

To determine whether alpha-stat or pH-stat strategy should be used, 20 patients undergoing coronary artery bypass grafting during moderate hypothermic hemodilutional cardiopulmonary bypass were studied. The carbon dioxide management during bypass was randomly done according to alpha-stat strategy in 10 patients (i.e., temperature-uncorrected PaCO2 was kept near 40 mm Hg and uncorrected pHa was kept at about 7.4) and according to pH-stat strategy in the other 10 patients (i.e., temperature-corrected PaCO2 was kept near 40 mm Hg and uncorrected pHa was kept at about 7.4). In both groups, when the central venous temperature was stable at 26.5 +/- 2.5 degrees C, the perfusion flow was altered sequentially from 2.4 to 1.8 and 1.2 L.min-1.m-2. The mixed venous oxyhemoglobin saturation at the different perfusion flows was monitored by the Oxy-Stat meter and was correlated with the corresponding mixed venous oxygen tension to construct an oxyhemoglobin dissociation curve. Also, the whole-body oxygen consumption at the different perfusion flows was computed. The whole-body oxygen consumption and the oxyhemoglobin dissociation were not significantly different between the alpha-stat and the pH-stat groups. In both groups, the dissociation curve is shifted to the left, but the oxygen consumption per unit time does not significantly change despite decreasing the perfusion flow from 2.4 to 1.2 L.min-1.m-2. The results suggest that oxygen delivery is not impaired during moderate hypothermic cardiopulmonary bypass independent of whether alpha-stat or pH-stat strategy is used.

Amniotic fluid embolus: can we affect the outcome?

Purpose of review Amniotic fluid embolism is a rare catastrophe unique to pregnancy. Its mortality rate remains high despite efforts at prompt and aggressive management protocols, highlighting the need to maintain a high index of suspicion. Recent findings The intrusion of amniotic fluid into the maternal bloodstream may lead in certain women to a complex series of physiological reactions mimicking those seen in human anaphylaxis or sepsis, negating the purely embolic phenomenon theory as previously understood. The clinical picture is the sudden onset of cardiovascular collapse, cyanosis, haemorrhage or disseminated intravascular coagulopathy, during or soon after delivery. Summary The mainstay of a successful outcome remains the identification of high-risk patients, as well as early clinical diagnosis and management.