David S. Beebe

Hemodynamic, respiratory, and metabolic effects of laparoscopic cholecystectomy

In 10 patients undergoing laparoscopic cholecystectomy, creation of pneumoperitoneum caused immediate venous hypertension and stasis in the lower extremities as measured by percutaneous catheter and duplex scanning. These changes disappeared after deflation. As measured by spirometry, significant reductions in forced vital capacity of 23% and forced expiratory volume in 1 second of 22% were present 24 hours after surgery, and plasma interleukin-6 levels rose to 18 pg/mL. The visual analogue scale of resting pain increased to a median value of 2.5 postoperatively. When compared with other studies of open cholecystectomy, our results showed fewer restrictions of ventilation, lower cytokine levels, and lower pain scores. The minimal soft tissue trauma and early ambulation after laparoscopic cholecystectomy may decrease the risk of thrombosis despite an acute episode of venous stasis.

Effectiveness of preoperative sedation with rectal midazolam, ketamine, or their combination in young children

To determine which of three types of rectal sedation was most effective preoperatively in facilitating parental separation and intravenous cannulation in young children, 100 children 3.0 +/- 1.7 (mean +/- SD) yr of age were randomly assigned to four equal groups. One group (M-K-A) received rectal midazolam (0.5 mg/kg), ketamine (3 mg/kg), and atropine (0.02 mg/kg). The other sedation groups received the same doses of midazolam and atropine (M-A) or ketamine and atropine (K-A) alone, and the control group (A) received only rectal atropine. Most children in either the M-K-A (100%) or M-A (92%) groups separated easily from their parents without struggling or crying, significantly more than in the K-A (60%) or A (64%) groups. However, more children in the M-K-A group (44%) were asleep during separation than in the M-A group (8%; P < 0.05). Only 20% of the children in the M-A or M-K-A groups cried during intravenous catheter placement, significantly less than in the K-A (56%) or A (92%) groups. Intravenous catheter placement was also successful significantly more often in the M-A (80%) and M-K-A (84%) groups than in the K-A (48%) or A (40%) groups. Complications were similar among the groups, but there was evidence that midazolam prolonged recovery time in some patients. Rectal midazolam with or without ketamine is a useful technique when intravenous catheter placement before induction of anesthesia is desired.

High levels of carbon monoxide are produced by electro-cautery of tissue during laparoscopic cholecystectomy.

&NA; Pyrolysis of tissue in a hypoxic environment can produce carbon monoxide. The atmosphere of the peritoneal cavity is rendered hypoxic during laparoscopic cholecystectomy by insufflation with 100% carbon dioxide. To determine whether carbon monoxide is produced by electrocautery of tissue during laparoscopic cholecystectomy, nine patients undergoing this procedure had the insufflation gas after use of electrocautery analyzed for carbon monoxide. Blood was analyzed for carboxyhemoglobin in these same patients to determine whether carbon monoxide was being absorbed in dangerous amounts. Carbon monoxide was present in the peritoneal cavity 5 min after use of electrocautery was initiated at a median concentration of 345 ppm (range 25‐1600 ppm), and at the end of surgery at a concentration of 475 ppm (range 100‐1900 ppm). This was well in excess of the 35 ppm upper limit for a 1‐h exposure set by the Environmental Protection Agency. The carboxyhemoglobin concentrations (mean ± SD) were the same at the beginning (1.3% ± 0.7%), end (1.2% ± 0.7%), and the day after surgery (1.1% ± 0.6%). Although there was no evidence of significant absorption of carbon monoxide in these patients, care should be taken to scavenge the gases produced by cautery of tissues to avoid operating room contamination during laparoscopic surgery. (Anesth Analg 1993;77:338‐41)

Trained nurses can provide safe and effective sedation for MRI in pediatric patients

Purpose: To determine the success rate, safety and complications using a standard protocol and trained nurses to provide sedation for MRI under the supervision of a radiologist.Materials and Methods: Nurses were trained to provide sedation via a standard protocol for pediatric patients undergoing diagnostic MRI. Oral chloral hydrate (80–100 mg·kg−1) was used for children less than 18 mo of age. Older children received either 1–6 mg·kg−1 pentobarbitaliv, with or without 1–2 µg·kg·hr−1 fentanyl, or 25 mg·kg−1 thiopentalpr. Sedation was defined as successful if it allowed completion of the MRI without image distorting patient movement. The records of 572 MRIs performed on 488 pediatric patients (mean age 5±4 yr; age 2 mo-14 yr) from 1991 to July 1995 were reviewed to determine the success rate and complications using the sedation program.Results: Most, 91.8% (525/572), of the MRIs were successfully completed in 445 patients. The reasons for failure were inadequate sedation (45, 95.7%) and coughing (2, 4.2%). The failure rate was much higher before 1994 (38/272, 14%) than after (9/300, 3%;P<0.0001). Failure was more common if rectal thiopental was used (23/172, 14%) than intravenous pentobarbital (19/256, 7.4%;P<0.05). The failure rate was also high in patients with a history of a behavioural disorder (10/59, 17%). There were no deaths or unexpected admissions as a result of the sedation program.Conclusion: A high success rate can be achieved as experience is gained using a standard protocol and trained nurses to sedate children for MRI.RésuméObjectif: Évaluer le taux de succès, la sécurité et les complications liés à l’usage, par du personnel infirmier formé, d’un protocole standard d’administration d’une sédation en vue d’un examen d’IRM sous la supervision d’un radiologiste.Méthode: Des infirmières ont été formées pour administrer la sédation selon un protocole standard à des patients pédiatriques devant subir un examen diagnostique d’IRM. L’hydrate de chloral oral (80–100 mg·kg−1) a servi pour les enfants de moins de 18 mois. Les plus âgés ont reçu soit 1–6 mg·kg−1 de pentobarbitaliv, avec ou sans 1–2 µg·kg·hr−1 de fentanyl, soit 25 mg·kg−1 de thiopentalpr. On considérait la sédation résussie quand l’IRM était achevé sans distorsion d’image par un mouvement du patient. Les enregistrements de 572 IRM réalisés chez 488 enfants (âge moyen de 5±4 ans; limite d’âge de 2 mois-14 jrs) de 1991 à juillet 1995 ont été revus pour l’évaluation du taux de succès et des complications liés au programme de sédation.Résultats: La plupart des examend d’IRM, 91,8 % (525/572), ont été réalisés avec succès chez 445 patients. Les échecs ont eu pour cause une sédation insuffisante (45, 95,7 %) et la toux (2, 4,2 %). Le taux d’échec a été beaucoup plus élevé avant 1994 (38/272, 14 %) qu’après (9/300, 3 %P < 0,0001). L’échec était plus fréquent avec l’usage de thiopental rectal (23/172, 14 %) qu’avec le pentobarbital intravenieux (19/256, 7,4 %;P<0,05). Le taux d’échec a été élevé également chez les patients qui présentaient des antécédents de troubles de comportement (10/59, 17 %). Aucun cas de décès ou d’admission imprévue n’a résulté de ce programme de sédation.Conclusion: Unb for taux de réussite peut être atteint à mesure que se développe l’expérience des infirmières formées à utiliser un protocole standard d’administration d’une sédation à des enfants pour un examen d’IRM.

Sodium nitroprusside in 2014: A clinical concepts review

Sodium nitroprusside has been used in clinical practice as an arterial and venous vasodilator for 40 years. This prodrug reacts with physiologic sulfhydryl groups to release nitric oxide, causing rapid vasodilation, and acutely lowering blood pressure. It is used clinically in cardiac surgery, hypertensive crises, heart failure, vascular surgery, pediatric surgery, and other acute hemodynamic applications. In some practices, newer agents have replaced nitroprusside, either because they are more effective or because they have a more favorable side-effect profile. However, valid and adequately-powered efficacy studies are sparse and do not identify a superior agent for all indications. The cyanide anion release concurrent with nitroprusside administration is associated with potential cyanide accumulation and severe toxicity. Agents to ameliorate the untoward effects of cyanide are limited by various problems in their practicality and effectiveness. A new orally bioavailable antidote is sodium sulfanegen, which shows promise in reversing this toxicity. The unique effectiveness of nitroprusside as a titratable agent capable of rapid blood pressure control will likely maintain its utilization in clinical practice for the foreseeable future. Additional research will refine and perhaps expand indications for nitroprusside, while parallel investigation continues to develop effective antidotes for cyanide poisoning.

Sinus arrest after intravenous neostigmine in two heart transplant recipients.

M any authors have stated that neuromuscular block can be safely reversed with either neostigmine or edrophonium in patients who have previously received an orthotopic heart transplant (1-5). The donor heart is denervated at the time of transplant, and the heart rate is determined by the intrinsic rate of the donor sinoatrial (SA) node. The native SA node remains intact but, at least initially, does not influence the heart rate. Until recently drugs that act indirectly upon the heart, such as neostigmine, atropine, or edrophonium, were not thought to affect the heart rate (14). However, a case has been reported in which neostigmine administration to reverse neuromuscular block in a heart transplant recipient caused transient bradycardia which was reversed with intravenous (IV) atropine (6). This case suggests that reversal of neuromuscular block with anticholinesterase drugs may affect cardiac function in patients who have received a heart transplant. In this report we describe two patients with heart transplants who developed sinus arrest after the reversal of neuromuscular block with neostigmine and glycopyrrolate.

Living liver donor surgery: Report of initial anesthesia experience

Abstract The charts and anesthetic records of 12 patients who donated the left lateral segment of their liver to a related infant or child to treat liver failure were retrospectively reviewed. Blood loss, need for transfusion, fluids administered, surgical length, and perioperative complications were investigated. The records also were examined to determine the hemodynamic stability of patients undergoing donor hepatectomy to assess their need for invasive monitoring. There were no episodes of hypotension or hemodynamic instability. The average operating time was 9.6 ± 1.1 hours. The blood loss was 562 ± 244 mL (range 300 to 1100 mL). Four patients received their own cell saver blood (200 mL, 220 mL, 300 mL, 475 mL), and one patient received 1 U (350 mL) of predonated autologous blood. The average hemoglobin decreased significantly (p = 0.001) from a preoperative value of 14.1 ± 1.2 to 12.3 ± 1.8 g/dL in the recovery room. All patients were extubated in the operating room or recovery room. Patients were discharged home in 6.9 ± 1.3 days (range 5 to 9 days). Living-related liver resection can be performed with noninvasive monitoring and without the need for heterologous blood products.

Anesthesia for Organ Transplantation

This review is divided into an overview encompassing organ transplantation in general and a discussion of topics specific to each organ system, primarily for the interest of the pediatric anesthesiologist and intensivist. In addition, the role of immunosuppressive agents, complications of infections

EVIDENCE OF VENOUS STASIS AFTER ABDOMINAL INSUFFLATION FOR LAPAROSCOPIC CHOLECYSTECTOMY

Intraoperative venous stasis may increase the risk for perioperative deep vein thrombosis and pulmonary embolism. To determine if abdominal insufflation during laparoscopic cholecystectomy causes venous stasis, eight patients undergoing this procedure had their left common femoral veins examined by a duplex scanner before and after abdominal insufflation; the veins then were examined again before and after deflation. The right femoral veins were catheterized to measure femoral venous pressures. Abdominal insufflation to 14 millimeters of mercury pressure increased femoral venous pressures (10.2 +/- 4.1 millimeters of mercury to 18.2 +/- 5.1 millimeters of mercury; p < 0.001) and slowed peak blood velocities (24.9 +/- 8.5 centimeters per second to 18.5 +/- 4.5 centimeters per second; p < 0.05) without changing the cross-sectional areas (1.1 +/- 0.4 centimeter squared to 1.2 +/- 1.5 centimeter squared; p = NS) of the common femoral veins. Insufflation also reduced or eliminated pulsatility in the common femoral veins in 75 percent of the patients, indicating that insufflation was causing partial proximal venous obstruction. After 80 +/- 21 minutes of surgery, these changes remained significant. Deflation of the abdomen restored normal venous pulsatility in all patients, reduced femoral venous pressures (18.5 +/- 5.2 millimeters of mercury to 12.2 +/- 9.8 millimeters of mercury; p < 0.001), increased the peak blood velocities (14.2 +/- 6.8 centimeters per second to 28.1 +/- 16 centimeters per second; p < 0.05) and decreased the cross-sectional areas (1.4 +/- 0.6 centimeters squared to 0.9 +/- 0.4 centimeters squared; p < 0.05) of the common femoral veins, indicating venous decompression had occurred. The results suggest abdominal insufflation causes venous stasis during laparoscopic cholecystectomies. Measures shown to reduce intraoperative venous stasis, such as pneumatic compressive stockings, may benefit patients undergoing these procedures.

Cyanide toxicity in juvenile pigs and its reversal by a new prodrug, sulfanegen sodium

BACKGROUND: Cyanide (CN) toxicity is a serious clinical problem and can occur with sodium nitroprusside (SNP) administration, accidental smoke inhalation, industrial mishaps, and bio-terrorism. In this study, we induced severe CN toxicity independently with SNP or sodium cyanide (NaCN) in a juvenile pig model to demonstrate reversal of severe CN toxicity with a new antidote, sulfanegen sodium, a prodrug of 3-mercaptopyruvate. METHODS: SNP study: A pilot study in 11 anesthetized, mechanically ventilated juvenile pigs allowed us to determine the dose of SNP to induce CN toxicity. Blood CN, serum lactates, and blood gases were monitored. CN toxicity was defined as the occurrence of severe lactic acidosis accompanied by significant elevation in blood CN levels. Based on this pilot study, 8 anesthetized pigs received a high-dose IV infusion of SNP (100 mg/h) for 2 hours to induce CN toxicity. They were then randomized to receive either sulfanegen sodium or placebo. Four pigs received 3 doses of sulfanegen sodium (2.5 g IV) every hour after induction of severe CN toxicity, and 4 pigs received placebo. NaCN study: A pilot study was conducted in 4 spontaneously ventilating pigs sedated with propofol plus ketamine to demonstrate hemodynamic and metabolic stability for several hours. After this, 6 pigs were similarly sedated and given NaCN in bolus aliquots to produce CN toxicity ultimately resulting in death. Hemodynamics and metabolic variables were followed to define peak CN toxicity. In another group of 6 pigs, severe CN toxicity was induced by this method, and at peak toxicity, the animals were given sulfanegen sodium (2.5 g IV) followed by a repeat dose 60 minutes later in surviving animals. RESULTS: SNP study: The pilot study demonstrated the occurrence of a significant increase in blood CN levels (P < 0.05) accompanied by severe lactic acidemia (P < 0.05) in all pigs receiving a high dose of SNP. Administration of the sulfanegen antidote resulted in progressive significant reduction in blood lactate and CN levels with 100% survival (P < 0.05), whereas the placebo-treated pigs deteriorated and did not survive (P < 0.05). NaCN study: NaCN injection resulted in CN toxicity accompanied by severe lactic acidosis and mortality in all the pigs. Sulfanegen sodium reversed this toxicity and prevented mortality in all the pigs treated with this antidote. CONCLUSIONS: CN toxicity can be successfully induced in a juvenile pig model with SNP or NaCN. The prodrug, sulfanegen sodium, is effective in reversing CN toxicity induced by SNP or NaCN.