Cardiac transplantation: a prospective comparison of ketamine and sufentanil for anesthetic induction

The Use of Continuous Ketamine for Analgesia and Sedation in Critically Ill Patients with Opioid Abuse: A Case Series

Managing pain and agitation in patients with opioid abuse is becoming more common in intensive care units. Tolerance to commonly used agents is often observed, leading to inadequate pain control and increased agitation. Ketamine's unique mechanism of action and opioid-sparing effects make it an ideal agent for patients with suboptimal response to opioid therapy. This report describes our experience using continuous ketamine infusions for analgesia and sedation in four mechanically ventilated patients with histories of opioid abuse that had suboptimal response to standard therapy. Ketamine was successful in improving analgesia and sedation in three patients while reducing the need for other analgesics and sedatives with minimal adverse effects. Continuous ketamine infusions may be useful to facilitate mechanical ventilation in patients with histories of opioid abuse with minimal toxicity. More information is needed on the optimal dose and titration parameters.

Anesthesia for Heart Transplantation

Although several new surgical therapies hold promise for changing the surgical approach to heart failure, the most effective therapy currently for patients with end- stage congestive heart failure is heart transplantation. The challenges posed to the anesthesiologist caring for these patients are great, and are increasing as a result of a shift toward transplanting medically unstable pa tients. The anesthetic management of patients undergo ing heart transplantation requires a knowledge of the pathophysiology of heart failure, the altered pharmacody namics of anesthetics in the patient with heart failure, treatment of right heart failure, as well as the impact of new surgical therapies on cardiovascular function.

Anesthesia for children with pericardial effusion: a case series

OBJECTIVES AND AIMS

  To review the anesthetic management of children requiring surgical intervention for pericardial effusion, determine the nature and frequency of complications and define risk factors that predict perioperative risk.

BACKGROUND

Anesthesia in the presence of a pericardial effusion may be associated with significant hemodynamic compromise particularly during induction. However, the literature specifically concerning children is limited to a single-case report.

METHODS

A retrospective case review of children undergoing general anesthesia for surgical treatment for pericardial effusion between 1999 and 2008 at a single institution.

RESULTS

Sixty-five children underwent 79 general anesthetics for surgical treatment for pericardial effusion. Median age was 4 years (2 weeks-16 years), and median weight 15 kg (range, 2.5-96 kg). Fifty-five children (84%) developed effusions following cardiac surgery. The commonest induction agent was ketamine (25/65, 38%), and the majority of children (52/65, 80%) were intubated and ventilated for the procedure. Seven children (11%) suffered from eight major complications, and 14 children (22%) suffered from a minor complication. Major complications were more common in children with preoperative tachypnoea (P = 0.01) and cardiac tamponade on preoperative echocardiogram (ECHO) (P = 0.001). Preoperative hypoxia had a sensitivity of 92% and a positive likelihood ratio of 5.2 (95% CI 1.5-17.5) for predicting all complications.

CONCLUSIONS

Anesthesia for pericardial effusion in children was associated with an adverse physiological event in one-third of children. Major complications may be predicted by preoperative tachypnoea and cardiac tamponade on preoperative ECHO, and all complications may be predicted by preoperative hypoxia. The anesthetic technique included a variety of induction agents, and we cannot recommend a particular approach.

Anesthetic Management of Pediatric Cardiac Transplantation

Cardiac transplantation has become a widely accepted ther apy for a variety of end-stage cardiac diseases in pediatric patients. From November 1985 to November 1999, 347 pe diatric cardiac transplantations were performed at Loma Linda University Medical Center (LLUMC), including 235 in children younger than 6 months of age. It is essential to be familiar with the physiologic and anatomic characteristics of the recipient. Hypoplastic left heart syndrome is the most frequent congenital disorder leading to transplant in neo nates at LLUMC, with diseases presenting with left ventric ular failure accounting for the majority of the remainder of patients. We have assessed many variables for a possible relationship to intraoperative or postoperative compli cations, including anesthetic induction and maintenance agents, pH and base excess, as determined by arterial blood gas analysis before cardiopulmonary bypass (CPB), and he modynamic changes requiring treatment before CPB. Al though we have noticed an association between low patient temperature or mechanical stimulation at the time of ster notomy, and hemodynamic complications before CPB, in our experience no single anesthetic technique or intraoper ative event, including ventricular fibrillation, predicts early mortality. We believe anesthetic management of pediatric cardiac transplant recipients should be tailored to fit the pathophysiology present.

Adverse cardiovascular effects of ketamine infusion in patients with catecholamine-dependent heart failure

The longterm effects of ketamine on haemodynamic parameters and exogenous catecholamine requirements were studied in twenty-five critically ill patients with catecholamine-dependent heart failure. Following sedation with midazolam (0.15 +/- 0.07, mg.kg-1.h-1) and sufentanil (0.88 +/- 0.33 microgram.kg-1.h-1), patients with impaired left ventricular function (left ventricular ejection fraction area 30 +/- 7%) were randomly assigned to receive ketamine (2.5 +/- 0.9 mg.kg-1.h-1) and midazolam (Group A) or remained on sufentanil/midazolam (Group B). Haemodynamic measurements were performed throughout the first 24 hours after randomization. In group A cardiac index decreased by 21% (P = 0.01), mean arterial pressure increased by 13% (P = 0.01), mean pulmonary artery pressure by 14% (P = 0.04), pulmonary capillary wedge pressure by 20% (P = 0.03), and systemic vascular resistance index by 38% (P < 0.001). No significant cardiovascular effects were observed in Group B. Neither group had significant changes of exogenous catecholamine requirement. In conclusion, ketamine exhibits potential negative cardiovascular effects in patients with catecholamine-dependent heart failure. Therefore, ketamine should not be considered a first line drug for longterm sedation of patients with impaired left ventricular function.

[Vascular effects of ketamine during anesthesia with diazepam and fentanyl]

Twenty-six adults undergoing elective cardiac surgery were anaesthetized with diazepam and fentanyl (induction with 200 micrograms.kg-1 and 30 micrograms.kg-1 respectively, maintenance with incremental doses). Normothermic constant perfusion output cardiopulmonary bypass was carried out with a membrane oxygenator, haemodilution with Ringer's lactate solution, and cardioplegia with St. Thomas's Hospital solution. The patients were randomly assigned to two groups. They were given either 2 mg.kg-1 of ketamine (group 1) or placebo (5 ml of normal saline) (group 2) via the venous line of the oxygenator. The non pulsatile flow was then kept at a steady rate of 2.41 x min-1.m-2, and no other infusion or treatment was started during the study period (ten minutes). The mean arterial pressure and blood reservoir level were measured every min during this period. The systemic vascular resistances did not change significantly in either group, but remained 27% lower in the ketamine group than in the placebo group (p less than 0.01). The blood reservoir level was 37% higher in the ketamine group (p less than 0.01), suggesting a decreased venous capacitance. It is therefore concluded that ketamine leads to venous constriction, and probably arterial dilation, during fentanyl-diazepam anaesthesia and normothermic cardiopulmonary bypass. The venous effects of ketamine could explain why it is usually well tolerated in hypovolaemic states.