Intraoperative Requirements Research Articles

Coagulation techniques are not important in directing blood product transfusion during liver transplantation

Preoperative acquired clotting parameters such as prothrombin time, activated partial thromboplastin time, antithrombin III, platelet concentration, and fibrinogen show coagulopathy caused by insufficiency of the diseased liver. Intraoperative determination of clotting factors or parameters is not helpful to direct intraoperative transfusion of blood, blood components, or platelets because transfusions performed solely for correction of clotting data do not correlate with the real intraoperative requirements and increase the costs of orthotopic liver transplantation. However, the use of antihyperfibrinolytic drugs seems to reduce intraoperative blood loss. Patients with cirrhotic disorders caused by portalvenous hypertension show extensive collaterals and increased intravascular blood volume. Thus it is plausible that especially overcorrection of blood loss during the surgical preparation in the preanhepatic phase of the operation results in extensive blood loss. Therefore, to avoid blood loss we attempt to keep volume substitution to a minimum during the preanhepatic phase of the operation. In contrast, during the anhepatic and postanhepatic phases we attempt to reestablish normovolemia by transfusing red packed blood cells and fresh-frozen plasma. Strictly confined use of blood products in the preanhepatic phase, followed by later correction of intravascular blood volume, may reduce intraoperative blood loss; it also seems to ensure adequate substitution of clotting factors.

Coagulation techniques are not important in directing blood product transfusion during liver transplantation

Preoperative acquired clotting parameters such as prothrombin time, activated partial thromboplastin time, antithrombin III, platelet concentration, and fibrinogen show coagulopathy caused by insufficiency of the diseased liver. Intraoperative determination of clotting factors or parameters is not helpful to direct intraoperative transfusion of blood, blood components, or platelets because transfusions performed solely for correction of clotting data do not correlate with the real intraoperative requirements and increase the costs of orthotopic liver transplantation. However, the use of antihyperfibrinolytic drugs seems to reduce intraoperative blood loss. Patients with cirrhotic disorders caused by portalvenous hypertension show extensive collaterals and increased intravascular blood volume. Thus it is plausible that especially overcorrection of blood loss during the surgical preparation in the preanhepatic phase of the operation results in extensive blood loss. Therefore, to avoid blood loss we attempt to keep volume substitution to a minimum during the preanhepatic phase of the operation. In contrast, during the anhepatic and postanhepatic phases we attempt to reestablish normovolemia by transfusing red packed blood cells and fresh-frozen plasma. Strictly confined use of blood products in the preanhepatic phase, followed by later correction of intravascular blood volume, may reduce intraoperative blood loss; it also seems to ensure adequate substitution of clotting factors.

The prophylactic effect of aprotinin on intraoperative bleeding in liver transplantation: A randomized clinical study

Fibrinolysis has been recognized as an important cause of intraoperative bleeding during orthotopic liver transplantation (OLT). Several investigators have used prophylactic administration of aprotinin in patients to inhibit fibrinolysis and to decrease transfusion requirements, morbidity, and mortality. Nevertheless, the role of aprotinin in this situation is not yet clear. The goal of this study was to determine the effects of prophylactic administration of aprotinin on intraoperative bleeding and blood requirements, and on hemostatic changes during OLT. Eighty consecutive patients were included in a double-blind, prospective study and were randomized in two groups. In group A (n = 39), an initial dose of 2 x 106 kallikrein inactivator units (KIU) of aprotinin was administered in the induction of anesthesia followed by infusion of 5 x 105 KIU/h until the end of the procedure. The control group (n = 41) received an identical volume of saline solution. The majority of the operations were performed with vena cava preservation (piggy-back technique) without venovenous bypass. During the anhepatic phase, a significant increase in levels of tissue plasminogen activator, thrombin- antithrombin complexes (TAT) and D-dimers (DD) was noted in both groups. A significant increment of TAT was observed in group A during reperfusion. The remaining hemostatic parameters were similar in both groups. Intraoperative requirements of packed red cells, fresh-frozen plasma (FFP), platelets, and cryoprecipitate were similar in the two groups. Our results suggest that prophylactic administration of aprotinin is not useful in reducing bleeding and blood product requirements during OLT. (Hepatology 1997 Nov;26(5):1143-8)

Continuous Caudal Anaesthesia with Chloroprocaine as an Adjunct to General Anaesthesia in Neonates

TOBIAS, J. D.; RASMUSSEN, G. E.; HOLCOMB, G. W.; BROCK, J. W. III; MORGAN, W. M. Author Information

Laparoscopically assisted abdominal aortic aneurysm repair. A report of 10 cases.

Laparoscopic surgery decreases postoperative pain and length of hospital stay. Whether laparoscopically assisted abdominal aortic aneurysm (AAA) repair can be safely and reliably performed is unknown. This prospective study was designed to establish the feasibility of laparoscopically assisted AAA repair and its effects on intraoperative and postoperative variables. With IRB approval, 10 patients with infrarenal AAA requiring a tube graft underwent laparoscopically assisted AAA repair. The procedure consisted of laparoscopic dissection of the aneurysm neck and iliac vessels. Then, through an 8-11-cm minilaparotomy, a standard endoaneurysmorrhaphy was performed. Data included laparoscopic and total operative times, blood loss, fluid requirements, duration of nasogastric suction (NGT), and lengths of intensive care unit (ICU) and postoperative hospital stays. Laparoscopically assisted AAA was completed in nine of 10 patients. The first patient was converted to a standard incision because the aneurysm neck could not be adequately dissected. Laparoscopic and total operative times were 1.8 +/- 0.4 and 4.5 +/- 0.7 h, respectively. Mean blood loss was 1 +/- 0.6 l. Intraoperative fluid requirement was 6.6 +/- 1.3 l. The duration of NGT suction was 1.8 +/- 1.0 days. The ICU stay was 2.1 +/- 0.8 days and hospital stay was 6.7 +/- 2.5 days. There were two minor complications and no deaths. Laparoscopically assisted AAA repair is technically feasible with acceptable blood loss, operative time, morbidity, and mortality. Potential advantages may be early removal of the NGT and shorter ICU and hospital stays. Prospective randomized trials are needed to determine if laparoscopically assisted AAA repair is advantageous.

Postoperative analgesia and intraoperative inhalational anesthetic requirements during umbilical herniorrhaphy in children: Postincisional local infiltration versus preincisional caudal epidural block

Study Objective: To determine the postoperative analgesic efficacy of, and the effects on, intraoperative inhalational anesthetic requirements of preincisional caudal epidural block versus postincisional infiltration of local anesthetic following umbilical herniorrhaphy in children. Design: Randomized, double-blind, prospective study. Setting: University medical center. Patients: 16 ASA status I and II patients (11 males, 5 females), ages 11 to 20 months, weighing up to 17 kg. Interventions: During standard anesthetic care, 16 children were randomized to receive either caudal block with 1.5 ml/kg of 0.2% bupivacaine (group 1) or local infiltration of the surgical site with up to 1.2 ml/kg of 0.25% bupivacaine (Group 2). Measurements and Main Results: Patients in Group 1 had significantly decreased pain scores and requirements for supplemental postoperative intravenous (IV) fentanyl. Five of eight patients in Group 1 did not require supplemental IV fentanyl during their in-hospital postoperative course, while all eight patients in Group 2 required supplemental IV fentanyl. The patients who received caudal epidural block also had decreased intraoperative requirements for isoflurane, shorter time to extubation (4.1 ± 0.8 min vs. 8.4 ± 1.5 min), and quicker discharge home (129 ± 13 min vs. 163 ± 22 min). Five of eight patients in Group 1 were ready for discharge at our usual time of 120 minutes, as opposed to one of eight patients in Group 2. Conclusion: Preincisional caudal epidural block is more effective in controlling pain following umbilical herniorrhaphy than is postincisional local infiltration.

Nicardipine for controlled hypotension during spinal surgery.

Nicardipine is the first intravenously administered dihydropyridine calcium channel blocker. Its primary physiologic actions include vasodilatation with limited effects on the inotropic and dromotropic function of the myocardium. Several reports have documented its use in adult patients for pharmacologic control of blood pressure. We present our experience with nicardipine as an agent for controlled hypotension during spinal surgery in 24 children. After the induction of general anesthesia, nicardipine was started at 5 (22 patients) or 10 micrograms/kg/min (two patients). The target mean arterial pressure (MAP) of 55-65 mm Hg was reached in 5.1 +/- 2.1 min (range, 2-10). Intraoperative infusion requirements to maintain the target MAP varied from 0.5 to 7 micrograms/kg/min (mean, 2.5 +/- 1.1). No adverse effects related to nicardipine were noted. Nicardipine appears to be an effective agent for controlled hypotension in children. Future studies are required to determine its advantages/disadvantages compared with more commonly used agents such as sodium nitroprusside or adrenergic antagonists.

Continuous caudal anaesthesia with chloroprocaine as an adjunct to general anaesthesia in neonates.

The authors prospectively evaluated the use of a continuous caudal epidural infusion of chloroprocaine as an adjunct to general anaesthesia during intra-abdominal surgery in neonates. The technique was used in 25 neonates ranging in age from 1 to 28 days and in weight from 2.2 to 4.9 kg. Following anaesthetic induction and tracheal intubation, an initial bolus dose of chloroprocaine 3% (1 or 1.5 ml.kg-1) was followed by a continuous infusion of 1 or 1.5 ml.kg-1.hr-1 administered through a caudal epidural catheter. No parenteral opioids were administered. The duration of the surgical procedures varied from one hour five minutes to three hours 15 min. The first three neonates received a bolus dose of 1.0 ml.kg-1 followed by an infusion of 1.0 ml.kg-1.hr-1 chloroprocaine 3%. These three neonates required an additional bolus dose followed by an increase in the infusion to 1.5 ml.kg-1.hr-1 to provide surgical anaesthesia. Adequate intraoperative anaesthesia was achieved in all 25 neonates with an infusion of 1.5 ml.kg-1.hr-1 of chloroprocaine 3%. This was evidenced by a lack of haemodynamic response to surgical manipulation. No neonate required more than 0.2% isoflurane or 70% nitrous oxide in oxygen. No episodes of haemodynamic instability (decreased blood pressure/bradycardia) related to the caudal epidural anaesthesia were noted. Twenty-three of 25 of the neonates' tracheas were extubated immediately (within 10 minutes) following the surgical procedure. Caudal anaesthesia with a continuous infusion of chloroprocaine can be used as an adjunct to general anaesthesia during abdominal surgery in neonates. Our initial experience suggests that the combined technique may eliminate the need for parenteral opioids and limit the intraoperative requirements for inhalational anaesthetic agents.

Intraoperative glycaemic control in non-insulin-dependent and insulin-dependent diabetes

We have compared intraoperative glycaemic control, insulin requirements and metabolic and endocrine variables in 40 non-insulin-dependent diabetic patients (NIDDM) and 40 insulin-dependent diabetic patients (IDDM) undergoing general anaesthesia for elective procedures. Two i.v. insulin regimens were used: continuous i.v. infusion (group A: 1.25 u.h-1) and repeated i.v. boluses (10 u./2 h). Blood concentrations of glucose were measured every 15 min from just before induction of anaesthesia until 2 h after surgery. Plasma lactate and pyruvate concentrations, ketone bodies, C-peptide and counter-regulatory hormones were also measured. Glycaemia did not differ significantly in the two types of diabetes, regardless of the insulin therapy used. The amounts of insulin administered were similar in NIDDM and IDDM. There was no significant difference for other metabolic variables. Plasma concentrations of growth hormone (GH) increased significantly during surgery, especially in IDDM patients, but this change did not alter intraoperative glycaemic control. We conclude that mean glycaemic control, insulin requirements and development of ketone bodies in NIDDM and IDDM patients did not differ during the operative period, regardless of the insulin regimen used. Therefore, during the operative period, it is not necessary to modify the insulin regimen according to the type of diabetes. The consequences of increased plasma GH concentrations on glycaemic control in IDDM patients after operation are unknown.

Preoperative prediction for the use of cardiopulmonary bypass in lung transplantation

Cardiopulmonary bypass has been widely used in the management of isolated single and double lung transplantations. Although there are certain clear-cut preoperative indications for cardiopulmonary bypass, in many patients the decision to use this modality is based on the hemodynamic consequences of intraoperative pulmonary artery clamping. We have performed 109 isolated lung transplantations. In 69 patients (38 single lung transplantations and 31 double lung transplantations) cardiopulmonary bypass was initiated only on the basis of intraoperative hemodynamics. We have analyzed preoperative data from these 69 patients to determine whether an intraoperative requirement for cardiopulmonary bypass can be predicted. Of 38 single lung transplantations, 12 necessitated cardiopulmonary bypass (all patients had restrictive lung disease). No patients with obstructive lung disease who underwent single lung transplantation required cardiopulmonary bypass (p < 0.001). For single lung transplantations, 6-minute walk, the arterial desaturation/oxygen requirements on exercise, and the right ventricular ejection fraction were all significantly different between the cardiopulmonary bypass and noncardiopulmonary bypass groups (p < 0.001). Of 31 double lung transplantations, 10 patients required cardiopulmonary bypass (seven had bronchiectasis, two had obstructive lung disease, and one had restrictive lung disease). For obstructive lung disease, no preoperative parameters predicted cardiopulmonary bypass. In conclusion, cardiopulmonary bypass is not necessary for most patients undergoing lung transplantation (in the absence of an absolute preoperative indication). Obstructive lung disease rarely necessitates cardiopulmonary bypass. In single lung transplantations, the subsequent requirement for cardiopulmonary bypass can be predicted from preoperative cardiopulmonary performance. For double lung transplantations, the requirement for cardiopulmonary bypass is usually dependent on unpredictable intraoperative factors.

"Goal-directed" transfusion management leads to distinct reduction of fluid requirement in liver transplantation.

Complications in patients undergoing OLT, such as hemorrhagic events, are caused not only by surgical problems but also by the profound functional disturbances arising from hepatic insufficiency, which are at least partially cured by the procedure itself. Preoperative clotting data give insight only into the dysfunction of the explanted organ. Hence, we tried to perform a standardized, "goal-directed" anesthesiologic management in the perioperative phase in OLT, following strict indications for blood replacement according to diuresis, hemoglobin level, and hemodynamic parameters. We performed 200 OLTs in 185 patients, according to usual methods. The mean intraoperative fluid requirement was 884 ml of balanced salt solution, 8.1 units of RBC, and 9.4 units of FFP. During the first 24 hours postoperatively, an average of 2.4 units of RBC and 5.6 units of FFP had to be transfused. Currently, 170 of the 185 patients (91.9%) are alive and well. Our data demonstrate that a distinct reduction of transfusion rates in OLT is possible, neglecting clotting data and improving clotting function by avoiding hemodilution.

Retrospective statistical analysis of coagulation parameters after 250 liver transplantations.

Extensive transfusion of blood components as a typical feature of OLT has been described by many authors. The perioperative requirement for transfusion, however, follows a downward trend, although the indications for OLT have been extended. Functional disturbances such as hyperfibrinolysis or platelet dysfunction, demonstrated by laboratory tests, such as platelet counts, PT, aPTT, TT, fibrinogen, and ATIII are often used to direct the transfusion of blood components, although preoperative data give insight only into the insufficient function of the old liver, which will be explanted and replaced by the donor graft. We have described a retrospective statistical analysis of laboratory data, clinical data, and perioperative blood requirements from 250 liver transplantations performed in our hospital from 1988 to 1992. The OLT was performed according to the usual surgical methods using a venovenous bypass system. Intraoperatively, volume was restored with packed RBC and FFP according to hemodynamic data, hemoglobin, and diuresis; clotting data were not used as indications for blood replacement. This analysis demonstrated that neither preoperative nor intraoperative clotting parameters were able to allow a prediction of the intraoperative requirement for transfusion of blood components; these findings parallel those of previous reports. With respect to other studies showing that perioperative transfusion rates correlated with postoperative infections and mortality, we strongly suggest that perioperative clotting measures as indicators for transfusion requirement should be analyzed with caution. Whether other diagnostic methods such as TEG are useful alternatives has to be determined.

Impact of aprotinin on blood transfusion requirements in liver transplantation

A retrospective study was carried out to ascertain the blood bank provision required to support a liver transplant programme and to assess the effect of intraoperative aprotinin on blood product requirements in liver transplant recipients with cirrhosis. Sixty patients with end-stage liver disease underwent 62 consecutive orthotopic liver transplants between October 1988 and January 1991. The total and intraoperative requirements of red cells, platelets and fresh frozen plasma (FFP) were analysed for three groups of liver transplant recipients, those without cirrhosis (n = 15), those with cirrhosis (n = 25) and those with cirrhosis who received intraoperative aprotinin (n = 20). Fifteen without cirrhosis had mean total requirements of 15 units of red cells, 18 units of platelets and 16 units of FFP. Twenty patients with cirrhosis who received intraoperative aprotinin had broadly similar requirements. However, blood product requirements for 25 patients with cirrhosis were significantly greater (46 units of red cells, 41 units of platelets, 43 units of FFP, excluding the seven patients with primary biliary cirrhosis). We conclude that a liver transplant programme can be supported by a teaching hospital blood bank. The use of intraoperative aprotinin significantly reduces blood product requirements.

Anaesthesia for laparoscopic general surgery.

Laparoscopic surgery minimises postoperative morbidity. Patient benefits include reduction in postoperative pain, better cosmetic result and quicker return to normal activities. Hospital stay is shortened resulting in a reduction in overall medical cost. The intraoperative requirements of laparoscopic surgery however can lead to serious physiological changes and complications. While there is a low but definite perioperative mortality rate associated with minor gynaecologic laparoscopic procedures, laparoscopic general surgical procedures are performed on older patients and patients with acute surgical conditions and are likely to be associated with a higher incidence of perioperative complications. The major problems during laparoscopic surgery are related to the cardiopulmonary effects of pneumoperitoneum, systemic carbon dioxide absorption, extraperitoneal gas insufflation, venous gas embolism and unintentional injuries to intra-abdominal structures. An appraisal of the potential problems is essential for optimal anaesthetic care of patients undergoing laparoscopic surgery. Appropriate anaesthetic techniques and monitoring facilitate surgery and allow early detection and reduction of complications. The need for rapid recovery and short hospital stay impose additional demands on the anaesthetist for skillful practice.

Liver transplantation in malignant primary hepatic neoplasms

Between April 1986 and August 1990, 151 liver transplantations were performed at our institution, 16 (11%) of them in 14 patients with primary hepatic tumors. There were 12 hepatocellular carcinomas, 1 angiosarcoma, and 1 Klatskin tumor. None of the tumors was resectable, and there was no preoperative evidence of extrahepatic tumoral extension. Exploratory laparotomy was performed prior to transplantation in three patients and selective embolization of the tumor in six patients. There was no difference in the intraoperative requirements for blood or plasma in the patients with hepatic tumors when compared with other transplant recipients (28.6 ± 23.6 units packed red blood cells [PRBC] versus 20.1 ± 17.8 units PRBC, and 17.9 ± 12.2 units plasma versus 17.1 ± 10.5 units plasma, respectively). Extracorporeal venovenous bypass was used in all but one patient. There was no significant differences in the incidence of acute rejection or in the length of hospitalization in these patients when compared with other transplant recipients. All patients received triple immunosuppressive therapy (corticosteroids, azathioprine, and cyclosporin A). Intraoperative mortality was zero. At a mean of 13.3 months' follow-up (range: 1 to 47 months), 2 of 14 patients had died of sepsis and 1 of terminal cirrhosis (autopsies revealed no evidence of tumor recurrence); 3 patients (21%) had recurrences of the tumor (1 in the central nervous system and liver, and the other 2 in the lung). One of the three patients with a recurrent tumor is still alive after 16 months. The remaining nine patients (64%) are still alive.

Cardiac preservation in patients undergoing transplantation: A clinical trial comparing University of Wisconsin solution and Stanford solution

Recent laboratory investigations have shown significantly improved donor heart preservation and function when the University of Wisconsin solution (UW) is used for arrest and storage. These findings prompted us to compare UW to Stanford solution in a clinical trial. After giving informed consent, patients were blindly randomized to receive a heart arrested and stored in UW or a heart arrested in Stanford solution and stored in normal saline. Orthotopic transplants were performed in a routine manner. Fourteen patients with a mean age of 54 years were randomized to UW, and 15 patients with a mean age of 51 years were randomized to Stanford solution. Mean donor ages (UW 27 years, Stanford 24 years) and ischemic times (UW 150 minutes, Stanford 135 minutes) were similar. Several differences were observed intraoperatively. At end ischemia, mean adenosine triphosphate (UW 5.87 mmol/gm wet weight, Stanford 4.75 mmol/gm) and creatine phosphate (UW 9.26 mmol/gm, Stanford 4.75 mmol/gm) levels were higher in the UW hearts (p less than 0.05). Defibrillation requirements (UW 14% [2/14], Stanford 53% [8/15]) were significantly less in the UW group (p = 0.05). The number of patients requiring temporary intraoperative pacing also showed a significant difference with 7% (1/14) of UW patients versus 47% (7/15) of Stanford patients requiring pacing (p less than 0.05). Intraoperative requirement for inotropic support showed a trend in favor of the UW group. End-ischemic and postreperfusion histologic characteristics were similar between the two groups. No differences in hemodynamics or ejection fractions were noted postoperatively, but trends toward improved rhythm and decreased inotropic support were present in the UW group. Overall 6-month survival rates were similar (UW 86% [12/14], Stanford 93% [14/15]). No preservation-related deaths occurred. We conclude: (1) UW is a safe and effective preservation solution for human cardiac transplantation; (2) considering the improved end-ischemic adenosine triphosphate and creatine phosphate levels, decreased defibrillations, decreased intraoperative pacing, and trend toward decreased requirement for inotropic support in the UW group, UW appears to be superior to Stanford solution for donor heart preservation.

Maternal Analgesia and Neonatal Effects of Epidural Sufentanil for Cesarean Section

This study was designed to evaluate the maternal intraoperative and postoperative analgesia and neonatal effects of adding sufentanil to epidural anesthesia for cesarean section before the skin incision. Forty-five multipara were randomized in three equal groups to receive sufentanil 80 micrograms, 50 micrograms, or saline with the epidural lidocaine. Intraoperative and postoperative analgesia and side effects were recorded. Infants were evaluated by Apgar score at one and five minutes and by Neurologic and Adaptive Capacity Score and Early Neonatal Neurobehavioral Scale at one, four and 24 hours of life. Superior analgesia, with no intraoperative requirements for supplemental narcotics, was obtained when either 80 micrograms or 50 micrograms sufentanil were added to lidocaine. Postoperative analgesia was prolonged after sufentanil, but side effects increased with the greater dose. The infants whose mothers received 80 micrograms sufentanil showed a mild neurobehavioral depression. It is therefore concluded that the addition of 50 micrograms of sufentanil improves both intraoperative and postoperative analgesia without significant neonatal effects.

Cost:Benefit Analysis of Elective Retroperitoneal Aortic Bypass

Of 72 consecutive patients needing abdominal aortic surgery, the transperi toneal approach (TA) was used in 34 patients. In this TA group, with a mean age of fifty-eight years, 28 patients had aortoiliac or aortobifemoral grafts. Of the 38 patients operated via the retroperitoneal approach (RA), 27 had aortoiliac disease and 11 had aneurysms. In the RA group, the mean age was fifty-nine years; 32 patients in this group had aortofemoral grafts. The groups were simi lar with regard to hypertension, heart disease, obstructive pulmonary disease, previous myocardial infarction, and stroke. The TA was associated with the larger intraoperative blood loss (1,100 mL) when compared with the RA (mean: 400 mL). Intraoperative crystalloid re quirements were significantly higher for the TA (5,500 mL) versus the RA (3,000 mL). Similarly, the intraoperative blood requirements were higher for the TA (3.0 units packed red blood cells [PRBC]) than the RA (1.0 unit PRBC). The numbers of units of PRBC transfused after surgery were significantly less with the RA (1.25 units) compared with the TA (0.5 unit). The total operative time for the TA was 225 minutes; the time for the RA was 165 minutes (p &lt; 0.01). The number of hospitalized postoperative days in the TA was 11.5 compared with 6 days in the RA; average number of days of nasogastric intubation was 4 days for the TA compared to 0.25 day for the RA; and tolerance for regular food was initiated at 5.5 days in the TA compared with 1.5 days in the RA. The number of hours of postoperative intubation for the TA was an average of 19.5 compared with 4.5 for the RA; the number of postoperative verbal orders in the TA was 14.0 compared with 4.5 in the RA; and complications in the TA were six times greater than in the RA. Most of the TA complications were pulmonary; these were not present in the RA. The incidence of wound infection was zero in both groups; mortality was zero in both groups. The average hospital cost of the TA was $20,125.26 compared with $5,164.05 for the RA. The RA for abdominal aortic vascular surgery is more cost effective than the TA.

ALFENTANIL AND PROPOFOL INFUSIONS FOR SURGERY IN THE BURNED PATIENT

We have studied combinations of alfentanil and propofol for total i.v. anaesthesia in 24 severely burned patients. No inhalation agents were used. After a loading dose of alfentanil 100 micrograms kg-1, the intraoperative requirement was 1.24 (SEM 0.7) micrograms kg-1 min-1, and after a propofol induction dose of 2 mg kg-1 the maintenance rate was 100 micrograms kg-1 min-1. Initial hypotension occurred after induction of anaesthesia, but during the operation, cardiovascular variables were stable. After adequate antagonism of neuromuscular block, respiratory depression persisted in three patients when the two agents were discontinued simultaneously; this was not seen when alfentanil was discontinued 15 min before propofol. Quality of recovery was good, and satisfactory postoperative analgesia was present in the majority of patients 2 h after operation. This study indicates that total i.v. anaesthesia with a combination of alfentanil and propofol appears to be satisfactory in burned patients.

Adverse Effects of Hypothermia in Postoperative Patients

The effect of intraoperative and postoperative temperature on morbidity, mortality, and other clinical risk factors was evaluated in 100 consecutive general surgical patients admitted postoperatively to a surgical intensive care unit. Hypothermia (temperature less than 97 degrees F) was present in 77 percent of the patients intraoperatively, in 53 percent at the end of surgery, and in 21 percent at 4 hours. Mortality was increased with patient age greater than 55 years, emergency surgery, operative blood pressure less than 100 mm Hg, operative fluid requirements greater than 1,500 ml/hour, temperature less than 97 degrees F at 2, 4, and 8 hours postoperatively, and presence of postoperative complications. Intraoperative fluid requirements were significantly greater for patients with mortality risk factors. Patients over 55 years of age were more often hypotensive and hypothermic than younger patients, but mortality was increased only for patients less than 55 years of age with a temperature of less than 97 degrees F at 8 hours or an operative blood pressure of less than 100 mm Hg. Mortality after general surgical procedures is increased with operative hypotensive and prolonged postoperative hypothermia. Hypothermic patients with mortality risk factors should be aggressively rewarmed postoperatively.