Marc P. Buise

A Macintosh Laryngoscope Blade for Videolaryngoscopy Reduces Stylet Use in Patients with Normal Airways

BACKGROUND:Although most tracheal intubations with direct laryngoscopy are not performed with a styletted endotracheal tube, it is recommended that a stylet can be used with indirect videolaryngoscopy. Recently, there were several reports of complications associated with styletted endotracheal tubes and videolaryngoscopy. In this study, we compared three videolaryngoscopes (VLSs) in patients undergoing tracheal intubation for elective surgery: the GlideScope® Ranger™ (GlideScope, Bothell, WA), the V-MAC™ Storz® Berci DCI® (Karl Storz, Tuttlingen, Germany), and the McGrath® (McGrath series 5, Aircraft medical, Edinburgh, UK) and tested whether it is feasible to intubate the trachea of patients with indirect videolaryngoscopy without using a stylet. METHODS:Four hundred fifty consecutive adults (ASA PS I–II) undergoing tracheal intubation for elective surgery were randomly allocated for airway management with one of the three devices. Anesthesia induction for tracheal intubation consisted of fentanyl-propofol-rocuronium. An independent anesthesiologist used the Cormack-Lehane grading system to score an initial direct laryngoscopic view using a classic metal Macintosh blade. After subsequent positive-pressure ventilation using a face mask and an oxygen-sevoflurane mixture for 1 min, the trachea was intubated using one of the three VLSs. During intubation, the following data were collected: intubation time, number of intubation attempts, use of extra tools to facilitate intubation, and overall satisfaction score of the intubation conditions. RESULTS:The trachea of every patient was intubated using the VLSs, and none of the patients required conversion to the classic Macintosh laryngoscope. All three VLSs offered equal or better view of the glottis as assessed by the mean Cormack-Lehane grade, compared with the traditional Macintosh laryngoscopy, including a larger viewing angle of the glottic entrance. The average intubation time was 34 ± 20 s for the GlideScope, 18 ± 12 s for the V-MAC Storz, and 38 ± 23 s for the McGrath VLS. Intubation with the Storz was faster (P < 0.05) than the other two VLS tested and necessitated fewer additional tools (P < 0.01), resulting in a higher first-pass successful intubation rate. A stylet had to be used in 7% of the patients in the Storz group versus about 50% of the patients when the other two VLS were used. CONCLUSIONS:The trachea of a large proportion of patients with normal airways can be intubated successfully with certain VLS blades without using a stylet, although the three studied VLSs clearly differ in outcome. The Storz VLS displaces soft tissues in the fashion of a classic Macintosh scope, affording room for tracheal tube insertion and limiting the need for stylet use compared with the other two scopes. Although VLSs offer several advantages, including better visualization of the glottic entrance and intubation conditions, a good laryngeal view does not guarantee easy or successful tracheal tube insertion. We recommend that the geometry of VLSs, including blade design, should be studied in more detail.

The effect of nitroglycerin on microvascular perfusion and oxygenation during gastric tube reconstruction

Esophagectomy followed by gastric tube reconstruction is the surgical treatment of choice for patients with esophageal cancer. Complications of the cervical anastomosis are associated with impaired microvascular blood flow (MBF) and ischemia in the gastric fundus. The aim of the present study was to differentiate whether the decrease in MBF is a result of arterial insufficiency or of venous congestion. To do this we assessed MBF, microvascular hemoglobin oxygen saturation (&mgr;HbSo2), and microvascular hemoglobin concentration (&mgr;Hbcon) simultaneously during different stages of gastric tube reconstruction. In 14 patients, MBF was determined with laser Doppler flowmetry, and &mgr;HbSo2 and &mgr;Hbcon were determined with reflectance spectro- photometry. After completion of the anastomosis, nitroglycerin was applied at the fundus. Although MBF did not change significantly in the pylorus, MBF decreased progressively during surgery in the fundus from 210 ± 18 Arbitrary Units at baseline (normal stomach) to 52 ± 9 Arbitrary Units after completion of reconstruction (mean ± sem; P < 0.05). There was no change in &mgr;HbSo2 and &mgr;Hbcon during the reconstruction. After application of nitroglycerin, MBF doubled. We conclude that MBF decreases during gastric tube reconstruction but that &mgr;HbSo2 and &mgr;Hbcon do not. This decrease might be the result of venous congestion, which can partly be counteracted by application of nitroglycerin.

Perioperative statin therapy in patients at high risk for cardiovascular morbidity undergoing surgery: a review

Statins feature documented benefits for primary and secondary prevention of cardiovascular disease and are thought to improve perioperative outcomes in patients undergoing surgery. To assess the clinical outcomes of perioperative statin treatment in statin-naive patients undergoing surgery, a systematic review was performed. Studies were included if they met the following criteria: randomized controlled trials, patients aged ≥18 yr undergoing surgery, patients not already on long-term statin treatment, reported outcomes including at least one of the following: mortality, myocardial infarction, atrial fibrillation, stroke, and length of hospital stay. The following randomized clinical trials were excluded: retrospective studies, trials without surgical procedure, trials without an outcome of interest, studies with patients on statin therapy before operation, or papers not written in English. The literature search revealed 16 randomized controlled studies involving 2275 patients. Pooled results showed a significant reduction in (i) mortality [risk ratio (RR) 0.53, 95% confidence interval (CI) 0.30-0.94, P=0.03], (ii) myocardial infarction (RR 0.54, 95% CI 0.38-0.76, P<0.001), (iii) perioperative atrial fibrillation (RR 0.53, 95% CI 0.43-0.66, P<0.001), and (iv) length of hospital stay (days, mean difference -0.58, 95% CI -0.79 to -0.37, P<0.001) in patients treated with a statin. Subgroup analysis in patients undergoing non-cardiac surgery showed a decrease in the perioperative incidence of mortality and myocardial infarction. Consequently, anaesthetists should consider prescribing a standard-dose statin before operation to statin-naive patients undergoing cardiac surgery. However, there are insufficient data to support final recommendations on perioperative statin therapy for patients undergoing non-cardiac surgery.

Intravenous nitroglycerin does not preserve gastric microcirculation during gastric tube reconstruction: A randomized controlled trial

IntroductionComplications of oesophagectomy and gastric tube reconstruction include leakage and stenosis, which may be due to compromised microvascular blood flow (MBF) in gastric tissue. We recently demonstrated that decreased MBF could be improved perioperatively by topical administration of nitroglycerin. The aim of the present study was to investigate whether nitroglycerin, administered intravenously during gastric tube reconstruction, could preserve tissue blood flow and oxygenation in the gastric fundus, and reduce the incidence of postoperative leakage.MethodsIn this single-centre, prospective, double-blinded study, we randomized 32 patients scheduled for oesophagectomy into two groups. The intervention group received intravenous nitroglycerin during gastric tube reconstruction, and the control group received normal saline. Baseline values for MBF, microvascular haemoglobin oxygen saturation and microvascular haemoglobin concentration were determined at the gastric fundus before and after gastric tube construction and after pulling up the gastric tube to the neck.ResultsMBF and microvascular haemoglobin oxygen saturation decreased similarly in both groups during gastric tube reconstruction and were comparable. The oesophageal anastomosis was controlled by contrast radiography before discharge from the hospital; leakage was observed in two patients (13%) in the nitroglycerin group and five patients (31 %) in the control group (not significant).ConclusionUnder stable systemic haemodynamic conditions, continuous intravenous administration of nitroglycerin could not prevent deterioration in gastric microvascular perfusion and microvascular haemoglobin saturation during gastric tube reconstruction. (Trial registration number NCT 00335010.)

Two-Lung High-Frequency Jet Ventilation as an Alternative Ventilation Technique During Transthoracic Esophagectomy

OBJECTIVEnThe aim of this study was to evaluate two-lung high-frequency jet ventilation during esophagectomy and evaluate the influence of high-frequency jet ventilation on pulmonary complications as compared with one-lung ventilation.nnnDESIGNnA retrospective study.nnnSETTINGSnA single-center study in a university hospital.nnnPARTICIPANTSnThe authors analyzed the data of patients who had undergone an elective esophagectomy by transthoracic esophagectomy between January 2000 and December 2006.nnnINTERVENTIONnThe patients had undergone a cervicothoracoabdominal subtotal esophagectomy via a right-sided thoracotomy. Patients with high-frequency jet ventilation were intubated with a single-lumen endotracheal tube, and an oxygen insufflation catheter was placed inside the endotracheal tube and connected to a high-frequency jet ventilator.nnnMEASUREMENTS AND MAIN RESULTSnEighty-seven patients were enrolled, 30 with high-frequency jet ventilation and 57 with 1-lung ventilation. Both groups were adequately oxygenated, but patients in the one-lung ventilation group had a higher PaCO2 (42.75 +/- 7.5 mm Hg) compared with that for the high-frequency jet ventilation group (35.25 +/- 8.25 mm Hg) (p < 0.05). There were no differences in postoperative respiratory complications between the 2 groups. Mean blood loss was significantly lower for patients in the high-frequency jet ventilation group (1,243 +/- 787 mL).nnnCONCLUSIONSnHigh-frequency jet ventilation to 2 lungs, using a single-lumen tube, is a safe and adequate ventilation technique for use during esophagectomy. High-frequency jet ventilation had no influence on the incidence of postoperative pulmonary complications but reduced perioperative blood loss and led to a decreased need for fluid replacement.

Characteristics and Outcome of Patients Admitted to the ICU Following Bariatric Surgery

BackgroundThis study evaluates the characteristics and outcome of patients admitted to the ICU following bariatric surgery.MethodsDescriptive study. A review of a prospectively collected database of our bariatric surgery procedures from 2003 until 2006 was performed. The study was performed in a tertiary level, mixed medical and surgical, adult ICU of a large referral hospital.ResultsOf the 265 patients undergoing bariatric surgery (mainly gastroplasties and Roux-en-Y gastric bypasses), 22 (8%) were admitted to the ICU, of which 14 (64%) were on an elective basis and eight (36%) emergently. Hospital length of stay (LOS) for all patients was 4.5xa0days and ICU LOS was 12xa0days. Most elective admissions were standard procedure because of obstructive sleep apnea (OSA) or super obesity, with a median ICU stay of 1xa0day. Emergent admissions were mainly done after emergent surgery due to surgical complications and had a median ICU stay of 8xa0days. Only two patients needed intensive care for more than 3xa0days. There were no deaths during ICU stay.ConclusionsThe ICU admission rate in our report is 8%. This study showed that 32 ICU days are needed per 100 diverse bariatric procedures. Most patients are admitted to the ICU for only a few days and the majority of the admissions is planned.

The effects of intravenous nitroglycerine and norepinephrine on gastric microvascular perfusion in an experimental model of gastric tube reconstruction

BACKGROUNDnEsophagectomy with gastric tube reconstruction is the surgical treatment for cancer of the esophagus. Perfusion of the anastomotic site of the tube depends exclusively on microcirculation, making it susceptible to hypoperfusion. It is unknown whether vasodilatation is superior to increased perfusion pressure to improve gastric tissue perfusion of the anastomosis.nnnMETHODSnWe performed a gastric tube reconstruction in 12 pigs, mean body weight 32 +/- 2 kg. Besides systemic hemodynamic parameters, gastric microvascular blood flow (MBF) was assessed with laser Doppler flowmetry and gastric microvascular HbO(2) saturation (microHbSO(2)) and Hb concentration (microHbcon) with spectrophotometry. Animals were randomized over 2 groups: with and without intravenous nitroglycerin (NTG). In both groups, mean arterial pressure (MAP) was increased from 50 to 110 mmHg with infusion of norepinephrine; in the NTG group, central venous pressure was maintained below 10 mmHg throughout the experiment with NTG.nnnRESULTSnExcept for central venous and pulmonary capillary wedge pressures, all hemodynamic parameters were similar in both groups. Especially in corpus and fundus, MBF decreased following surgery. However, overall MBF was significantly higher in the NTG group. Increasing MAP had no effect on fundus MBF. Gastric microHbSO(2) and microHbcon were not different between groups and did not change at higher MAP levels.nnnCONCLUSIONnIn our experimental model of gastric tube reconstruction, tissue perfusion is severely compromised; this effect is aggravated by systemic hypotension independent from cardiac output. Impaired venous outflow might contribute to this effect and can be counteracted with infusion of nitroglycerine.

Reflectance spectrophotometry and tissue oxygenation in experimental and clinical practice

Maintenance of adequate oxygen delivery (DO2) to the tissue cells can be considered a primary objective in intensive care and peri-operative patient management. Generally, it is believed that tissue hypoxia plays a significant role in the development of organ failure in critically ill patients and is a major factor in the pathogenesis of multi-organ dysfunction. The introduction of regional measurement techniques has highlighted the inadequacy of the information being generated by global measurements of hemodynamic and oxygen-related variables and has focused attention on the processes underlying microcirculatory oxygenation. It should be obvious that an adequate transport of oxygen by the cardiovascular system does not guarantee its delivery to the critical tissues of the body [1]. For this reason, assessment of tissue oxygenation is essential.

Perioperative respiratory care in obese patients undergoing bariatric surgery: Implications for clinical practice

Obesity is an increasing problem worldwide. The number of people with obesity doubled since the 1980s to affect an estimated 671 million people worldwide. Obese patients in general have an altered respiratory physiology and can have an impaired lung function, which leads to an increased risk of developing pulmonary complications during anaesthesia and after bariatric surgery (approximately 8%). Therefore the respiratory management of the bariatric surgical patient provides a number of challenges. This review will focus on the perioperative respiratory care in bariatric surgical patients discussing respiratory physiology in the obese and perioperative respiratory care in bariatric surgery. Finally the value of preoperative pulmonary function testing and preoperative OSAS screening will be discussed.

The effect of vasopressors on perfusion of gastric graft after esophagectomy.

Dear editor, We read with interest the article on gastric graft perfusion by Theodorou and co-workers. The article describes the negative effect of norepinefrin in gastric graft microcirculation. Gastric microvascular blood flow following esophagectomy is a difficult area for research at which we recently tried to contribute and we encourage every research in this specific field. However, we have some remarks on this study. First, the use of a hemorrhage model is not a good analog of the clinical situation. The use of vasopressors in case of hemorrhage will affect microcirculation. Hypotension during surgery and especially the hemodynamic effect of epidural analgesia, as mentioned in the conclusion, have other physiological mechanisms. Recently, the positive effect of epinephrine on gastric tube perfusion, in combination with epidural analgesia has been described. Second, in humans, the gastric tube is fashioned along the greater curvature of the stomach, and the blood supply is mainly based on the right gastricepiploic artery. In the model used, blood supply of the gastric graft was also based on the right gastroepiploic artery. In pigs, however, the main characteristic of vascular anatomy was a dominant left gastroepiploic artery, sometimes combined with well-defined short gastric arteries. Third, fluid management is of great importance in such a study, but no additional information is given. We wonder why blood pressure was so low at the end of the hemorrhage; in a pig of 30 kg, the loss of 200 ml blood is normally not accompanied by a decrease in pressure. We miss the information of central venous pressure and cardiac output. Animal number 5 is not recovering from the shock, and blood pressure is extremely low during steps 3 and 4. Is this animal still representative for the study? According to the protocol, the blood pressure should be increased from 80 to 90 mm Hg. Figure 1, in their article, shows this goal was never reached. Is this perhaps an effect of hypovolemia? Finally, in our opinion, the use of paired t test in this study design is not appropriate. Analysis of variance would be more correct for repeated measurements. Yours sincerely,