Probable case of vascular air embolism during endonasal CO2 laser surgery.

Laser surgery in narrow luminal cavities can lead to venous air embolism (VAE) due to high pressure or high flow clearing/cooling systems. We report the first case of initially misdiagnosed VAE during endonasal CO(2) laser surgery. A 56-year-old patient underwent uvulopalatopharyngoplasty and septoplasty with bilateral CO(2) laser turbinoplasty for turbinate hypertrophy and uvula deviation. At the end of the procedure (performed on the right nasal side), the patient presented with an abrupt decrease in end tidal carbon dioxide concentration (EtCO(2)), oxygen saturation (SpO(2)), and arterial pressure and experienced cardiac arrest. The patient was then successfully resuscitated and transferred to the ICU. After excluding pulmonary embolic disease with angio-CT scan, the event was interpreted as VAE due to the clearing/cooling gas flow of the CO(2) laser probe. Although capnometry cannot be considered specific to diagnose VAE, the occurrence of cardiac arrest preceded by an abrupt decrease in EtCO(2) and SpO(2) and the rapid resolution of symptoms after resuscitation led us to retrospectively suspect that VAE was the cause. The literature reports cases of VAE during laser surgery in narrow luminal cavities. When operating in narrow luminal cavities, using a liquid instead of a gas as a clearing/cooling system for the distal end of the probe in laser instruments and avoiding direct contact with tissues is advisable. Anesthesiologists, surgeons and the nursing staff practicing endoscopic laser surgery should have wide knowledge of the risks linked to this technique in order to minimize risk to the patient and to manage VAE should it eventually occur.

Incident reporting in anesthesia: misidentification of propofol concentrations due to similarities in drug packaging.

We report three cases of misidentification of propofol concentrations due to similarities in drug packaging, which were identified by the incident reporting system. Incident reporting is an approach used to assess the incidence of adverse and potentially adverse events, established to manage the contributing factors and to develop appropriate strategies to prevent errors in anesthesia. Inadvertently, 2% propofol was administered instead of 1%, causing overdosage and prolonged anesthesia in two consecutive patients in the same operating room. The third case was a near-miss that occurred in another operating room of the hospital: a syringe containing 2% propofol instead of 1% was prepared by the nurse, but the anesthesiologist checked the concentration before the induction of anesthesia. The errors occurred due to the presence of similar propofol packaging in the operating rooms. They were the result of both human error because the anesthesia personnel forgot to check the propofol concentration, and system failure, due to the color code of the packaging. In our experience, incident reporting detected the recurrence of drug related errors. Therefore, a preventive strategy was put in place by eliminating 2% propofol packaging from the operating rooms. This paper highlights the need for a cultural shift in the way we collect information on incidents, and it is an example of effective improvement to prevent drug error by reducing the complexity of the system.

Pharmacokinetics and efficacy of ropivacaine continuous wound instillation after joint replacement surgery.

BACKGROUND: As continuous wound instillation with local anaesthetic has not been evaluated after hip/knee arthroplasties, our study was designed to determine whether this technique could enhance analgesia and improve patient outcome after joint replacement surgery. METHODS: Thirty-seven patients undergoing elective hip/knee arthroplasties under spinal block were randomly assigned to two analgesia groups. Group M received continuous i.v. infusion of morphine plus ketorolac for 24 h. Then, a multi-hole 16 G catheter was placed subcutaneously and infusion of saline was maintained for 55 h. Group R received i.v. saline. Thereafter the wound was infiltrated with a solution of ropivacaine 0.5% 40 ml, then a multi-hole 16 G catheter was placed subcutaneously and an infusion of ropivacaine 0.2% 5 ml h(-1) was maintained for 55 h. Visual analogue scale scores were assessed at rest and on passive mobilization by nurses blinded to analgesic treatment. Total plasma ropivacaine concentration was measured. RESULTS: Group R showed a significant reduction in postoperative pain at rest and on mobilization, while rescue medication requirements were greater in Group M. Total ropivacaine plasma concentration remained below toxic concentrations and no adverse effects occurred. Length of hospital stay was shorter in Group R. CONCLUSION: Infiltration and wound instillation with ropivacaine 0.2% is more effective in controlling postoperative pain than systemic analgesia after major joint replacement surgery.

[Premedication with intranasal midazolam in children of various ages]. / Premedicazione con midazolam per via nasale nelle diverse età pediatriche.

BACKGROUND AND AIM: To evaluate the efficacy of premedication with midazolam (mdz) administered using a nasal route compared to diazepam (dz) administered by mouth in children of different ages. EXPERIMENTAL DESIGN: A comparative type study was performed in randomly selected pediatric patients undergoing surgery. The study lasted 3 months. SETTING: Recovery room and operating theatre for Pediatric Surgery and ENT. PATIENTS: A total of 248 patients were studied, divided into 3 age groups: group A were aged under 2 years; group B were pre-school age and group C were school-age. OPERATIONS: Two subgroups were formed based on the premedication used: group M = 0.2 mg/kg of mdz using a nasal route on arrival in the operating unit; group D = 0.2 mg/kg of dz per os 45' before induction. PARAMETERS STUDIED: In addition to acceptance of treatment, which was deemed to be good, poor or refused, the authors evaluated the level of sedation (score from 5 to 1: awake-asleep), anxiety on entering SO (score from 1 to 4: none-excessive) and the level of collaboration during the induction of general anesthesia (score 1-4: excellent-nil). RESULTS: The nasal route was well accepted by 59% of patients in group A, 62% of group B and 97% of group C. Statistical analysis using Kruskall Wallis test showed significant differences in groups A and B between the two subgroups M and D for all the parameters studied, whereas there were no significant differences in group C. CONCLUSIONS: Premedication with mdz using a nasal route was safe and efficacious, above all in early and later infancy.

Effect of nitric oxide on basal and TRH-or metoclopramide-stimulated prolactin release in normal men. volpi@ipruniv.cce.unipr.it.

In order to establish whether nitric oxide (NO) is involved in the regulation of basal and/or TRH- or metoclopramide (MCP)-stimulated PRL secretion, normal male subjects were treated i.v. with the NO-synthase (NOS) inhibitor N-nitro-L-arginine methyl ester (L-NAME) (40 mg/kg injected plus 50 mg/kg infused over 60 min) in basal conditions (N.7 subjects) or just before the PRL releasing hormone TRH (20 or 200 microg iv) (N.7 subjects) or the antidopaminergic agent MCP (1 or 10 mg iv) (N.7 subjects). In control experiments, subjects received normal saline instead of L-NAME. The administration of L-NAME modified neither the basal secretion of PRL, nor the PRL release induced by TRH (20 or 200 microg) or MCP (1 or 10 mg). These data suggest that in humans, NO is not involved in the control of PRL release at the anterior pituitary level.

Beneficial effects of verapamil in renal-risk surgical patients.

OBJECTIVE: To test whether the administration of calcium channel antagonists, such as verapamil (V), on the day before, during, and for 24-36 h after an important abdominal intervention, can lower the onset of acute renal failure (ARF), mostly in renal-risk patients, such as the aged. DESIGN: Randomized, nonblinded study. SETTING: Three surgical care university departments and two intensive care units of the same hospital (S. Anna, Ferrara, Italy). PATIENTS: Thirty-five elderly patients (61-83 years old) entered the study: 18 of them were given V; 17 were not treated and were considered as controls. The two study groups were overlapping as regards age, renal risk, and surgical challenge. The patients who underwent ARF (5 in the treated group, 7 among the controls) were rejected from the study. INTERVENTIONS: V was given on the eve of surgery at a dose of 80 mg/8 h per os and then through slow infusion (5 mg/4-6 h) during the next intra- and postoperative 24-36 h. Abdominal surgery was performed owing to gastric cancer (8 cases), colorectal neoplasia (10 cases), gallstone disease (4 cases), subrenal aortic aneurysm (6 cases), and iliofemoral obstructive arteriopathy (7 cases). MEASUREMENTS: Serum creatinine (SCr) was assessed to test renal function; 24-h urinary levels of brush-border enzymes (gamma glutamyl transferase, or gGT), lysosomal enzymes (N-acetyl-beta-D-glucosaminidase, or NAG), and beta 2-microglobulin (or beta 2M) were determined at T0 (on the eve of surgery), T1 (first and second day after), and T2 (7th and 8th day after) to demonstrate possible tubule cell damage. RESULTS: In the evaluated patients (13 treated with V and 10 untreated): (a) the 24-h urinary levels of gGt and NAG persisted unchanged throughout the study in the treated patients, whereas in the controls the same indices exhibited significant (p < 0.01) increases at T1 and T2; (b) the 24-h urinary levels of beta 2M showed significant (p < 0.01) increases in both groups from T0 to T1; however, at T2 these values tended to return to normal ranges in the treated patients, whereas they continued to be elevated in the untreated group. As regards the patients who underwent postoperative ARF, in the treated group urine output was significantly larger (p < 0.01 at T1 and p < 0.001 at T2), SCr was significantly (p < 0.05) lower, and the renal function recovered earlier (within 10 +/- 3 vs. 22 +/- 9 days) than in the controls. CONCLUSIONS: The administration of calcium channel antagonists to renal-risk patients during surgery and immediately before and after it has failed to prevent the onset of postoperative ARF. Nevertheless this procedure has been shown to somehow reduce surgery-mediated lesions of the tubule cells, as demonstrated by the finding of elevated urinary enzymes only in the untreated group.

[Low T3 syndrome (3,3',5-triiodothyronine) in relation to the extent of surgical trauma]. / La sindrome da basso T3 (3,3', 5-triiodotironina) in relazione all'entità del trauma chirurgico.

Thirty patients undergoing extra-thyroid surgery were divided into two groups (A and B) according to the extent of surgical stress (Group A: major surgery; Group B; minor surgery). Thyroid hormone levels were measured before the operation and up to the 3rd postoperative day in Group B and up to the 7th postoperative day in Group A. A low T3 syndrome was observed in all 30 patients examined of the first postoperative day (reduction of T3 and increase in rT3 without alterations of total thyroxin or signs of hypothyroidism) with normalisation of thyroid values by 3rd postoperative in Group B and later in Group A. The persistence of the syndrome in the latter group was due to the extent of surgical stress, the duration of anesthesia, the presence of stress factors such as staying in intensive therapy, painful symptoms and a negative energy balance during the first days following operation. This syndrome is indicative of a physiological adaptation process to reduce O2 consumption, basal metabolism and in particular protein catabolism.

[Vecuronium bromide in pediatric anesthesia]. / Bromuro di vecuronio in anestesia pediatrica.

Ninety patients were included in a study to assess the clinical characteristics of vecuronium bromide used in children. The myorelaxant was administered to all patients using different routes. The use of vecuronium at a dose approximately equal to 1ED95 was characterised by a duration of action sufficient to allow its use in short operations; on the other hand, it also produced a long induction-intubation interval and not optimal conditions in which to perform intubation. Conditions for intubation improved during induction via inhalation and there was a reduced induction-intubation interval compared to intravenous induction using the same dose of vecuronium. A further reduction in intubation time was obtained by increasing the dose from 50 to 150 micrograms/kg-1 together with an increased clinical duration of action. The "priming principle" technique also allowed intubation time to be shortened without variations in the duration of action provided a full dose of vecuronium, 100 micrograms/kg-1, was used. However, this was also associated with a notable incidence of adverse reactions. Of the various combinations examined, the most advantageous association of pre-dose and interval between doses was the association of a pre-dose of 10 micrograms/kg-1 and an interval of 4 min between doses. Lower doses countered the advantages of priming, whereas higher doses resulted in an increased number of adverse reactions without producing notable changes in the intubation time.

Thrombosis of the superior vena cava due to a central catheter for total parenteral nutrition.

Total parenteral nutrition (TPN) today is a fundamental procedure in the treatment of critically ill patients, especially if they have serious gastrointestinal diseases. However, use of the central venous catheter is connected with a very important morbidity. At the "Istituto di Patologia Chirurgica" and at the "Intensive Care Unit" of the University of Ferrara, we analyzed 59 cases of deaths from different diseases, on whom a postmortem examination had been performed. Twenty-seven patients had had no central venous catheter: none of them presented thrombosis of the central veins. Thirty-two patients had had a central venous catheter for TPN: five of them presented thrombosis of the central veins at the post-mortem examination. Except for one case who had thrombosis connected with a carcinoma of the right main bronchus, four cases (12.9%) presented thrombosis due to the central venous catheter. The subclavian vein seems to be more commonly connected with thrombosis than the jugular vein.

[Anesthesia and sickle cell disease]. / Anestesia e drepanocitosi.

Sickle cell anaemia is the most common hereditary haemoglobin pathology. It is found in either a homozygous or heterozygous form, associated in the latter case with other haemoglobinopathies. In view of the pathogenesis and the various related imbalances, amply confirmed by others, which can well prove disastrous, the pre, per and post-operative precautions to be adopted in such patients are assessed.

[Sickle cell anemia in surgical patients. Significance and problems]. / La falcemia nel paziente chirurgico. Significato e problemi.

Drepanocytosis, a disease notoriously widespread among blacks, is surprisingly frequent in certain Italian islands. Surgical aspects of the disease are discussed: erythrocyte sequestration attacks, pigmentary cholelithiasis, priapism, malleolar ulcers and vaso-occlusive attacks. A knowledge of such aspects is considered fundamental for the purposes of a reasoned differential diagnosis in the field of paediatric pathologies requiring surgery.

[Experimental intrauterine surgery. Morphological study of lung development in the sheep fetus with congenital diaphragmatic hernia]. / Chirurgia sperimentale endouterina. Studio morfologico dello sviluppo polmonare nel feto di pecora con ernia diaframmatica congenita.

Experimental comparison of the lungs of 7 sheep foetuses with surgically induced CDH and 7 controls permitted an assessment to be made of the changes that take place in lung growth, generally described as hypoplasia, through a study of their morphology and histology, and the lung: lamb weight ratio. Changes increased in gravity in function of the duration of hernia. They included: reduced alveolar expansion, fewer generations of bronchi and alveoli, and septal thickening. An increase in the smooth muscle component of 5th-6th generation arteries (i.e. resistance) may offer an explanation of the hypertension characteristic of CDH, and the non-reactivity of these vessels in response to vasodilators. It is also suggested that damage to the mesenchyma can be regarded as the sole cause of the changes in lung growth observed in CDH. Early treatment before these changes become irreversible is thus advisable.