Effect of cricoid pressure on the view at laryngoscopy

The impact of cricoid pressure on laryngoscopy is unknown. We have developed a quantitative method of recording the laryngoscopic view using a rigid, zero-degree endoscope. We found that an image matching the laryngoscopist's view could be obtained by positioning the endoscope along the laryngoscopist's 'line of sight'. Photographing this image allowed us to measure laryngeal exposure. We set out to define the effect of cricoid pressure on laryngoscopy using this method. In 40 patients undergoing elective surgery, laryngoscopy was performed with cricoid pressures of 0-60 N, increasing by increments of 10 N. We photographed the laryngoscopic view at each force and recorded dynamic images as cricoid pressure was released. The change in laryngoscopic view with increasing cricoid pressure fell into one of four broad patterns: little change (11 subjects); gradual deterioration (10 subjects); improvement at low force (< 20 N) followed by deterioration (9 subjects); improvement at high force (> 30 N) (10 subjects). We identified five subjects with a good initial view (anteroposterior length of the rima glottidis > 5 mm) who showed a marked deterioration in laryngoscopic view as cricoid pressure increased; in three of these subjects this progressed to obscure the larynx completely at a force of 30 N, 40 N and 60 N, respectively. We conclude that the effect of cricoid pressure on laryngoscopy is complex. However, in some individuals, a force close to that currently recommended (30 N) may cause a complete loss of the glottic view.     

Effect of ocular compression on intraocular pressure

A prospective double-blind controlled study was undertaken to determine the effects of different compression times applied to soften the eye on normal subjects. Application of the Honan intraocular pressure reducer (HIPR) produced a significantly (p less than 0.02) greater decrease in intraocular pressure when applied for 40 minutes (14.3 mmHg SD = 1.7) when compared to a five-minute application (8.8 mmHg SD = 1.7). No untoward effects were noted in these patients. Physiologic effects of external ocular compression are discussed.     

Effect of intraocular aspiration of sodium hyaluronate on postoperative intraocular pressure

A prospective, randomized, masked study was conducted to evaluate whether intraocular aspiration of sodium hyaluronate used in cataract surgery influenced postoperative intraocular pressure (IOP). Ninety-nine patients (105 eyes) underwent uncomplicated extracapsular extractions with posterior chamber intraocular lens implantation using 1% sodium hyaluronate (AMVISC). In 53 eyes, sodium hyaluronate was aspirated from the anterior chamber prior to wound closure. Sodium hyaluronate was left in the anterior chamber of 52 eyes. The IOP of 33 of the patients was measured 4 hours after surgery. No significant difference was found between the pressure in the eyes from which the sodium hyaluronate had been aspirated and the pressure in those from which it had not. The IOP of all the patients was measured on the first postoperative day. The mean 24 hours after surgery was 23.4 mm Hg in the aspirated eyes and 23.1 mm Hg in the not-aspirated group. Thirteen eyes in the aspirated group and 14 in the not-aspirated group had pressures above 30 mm Hg during the first 24 hours after surgery. There were no significant differences in visual outcome, patient discomfort, corneal clarity, anterior chamber inflammation, or subsequent IOPs during 3 months postoperative examination. Aspiration of sodium hyaluronate at the end of cataract surgery does not appear to significantly reduce either the incidence or the degree of postoperative pressure elevations.     

Effect of intravitreal silicone oil on intraocular pressure

We analyzed data obtained prospectively on 48 consecutive patients treated with intravitreal silicone oil. Forty percent were diabetic. Follow-up ranged from three to eight months. An increase in intraocular pressure (IOP) (defined as a rise 10 mmHg above the preoperative level) developed in 56% of the eyes in the postoperative period (range, 10 to 53.4 mmHg; mean rise, 21.63 mmHg). There was no significant difference in mean pressure rise between diabetic and non-diabetic eyes. The increase in IOP was transient in 78% of the patients. In 70% the IOP rose to a level greater than 22 mmHg. All of these patients required medical treatment, and some silicone oil was removed in six. Only 22% of those requiring treatment still received medication at follow-up. No patient in this series had uncontrolled IOP.     

Effect of premedication and various anesthetics on intraocular pressure

On the basis of investigations of the intraocular pressure in 172 patients the authors conclude that when choosing anesthetics and other drugs it is necessary to take into consideration their influence upon the intraocular pressure. In patients with high intraocular pressure the peridural anesthesia is expedient.     

不同靶浓度瑞芬太尼复合异丙酚对病人麻醉诱导时眼内压的影响

目的评价不同靶浓度瑞芬太尼对麻醉诱导时病人眼内压（10P）的影响。方法60例ASAⅠ级择期行鼻内窥镜手术病人，随机分为4组：R0组、R2组、R4组、R6组，每组15例。监测平均动脉压（MAP）、心率（HR）、脑电双频谱指数（BIS）、IOP。靶控输注异丙酚，血浆靶浓度为3μg/ml，5min后R2组、R4组、R6组分别靶控输注血浆靶浓度为2．4、6ng／ml瑞芬太尼，R0组静脉注射3μg/kg芬太尼，3min后气管插管。BIS低于70时静脉注射0．1mg／kg维库溴铵。记录入室后（基础值）、靶控输注瑞芬太尼前（T1）、气管插管前（T2）及气管插管后5min内最大值（T3）的IOP、MAP和HR。将靶控输注瑞芬太尼前后MAP与IOP的变化差值进行直线相关分析。结果与基础值相比，输注瑞芬太尼后R2组、R4组及R6组IOP下降（P〈0．05），组间比较差异无统计学意义（P〉0．05）；气管插管后心组IOP明显升高（P〈0．05），但仍低于基础值。R2组、R4组、R6组MAP与IOP的变化差值的相关系数分别0．803、0．835及0．883（P〈0．05），IOP下降与MAP下降程度呈正相关。结论靶控输注瑞芬太尼可明显降低麻醉诱导时病人的IOP，靶浓度4、6nG／ml可抑制气管插管引起眼内压的上升。     

Effect of pancuronium on intraocular pressure changes induced by succinylcholine

The study was undertaken to evaluate the influence of pretreatment with a small dose of pancuronium on intraocular pressure changes associated with administration of succinylcholine and tracheal intubation. Thirty patients divided into control and study groups were anaesthetized with sodium thiopentone (3-5 mg mg.kg-1) and intubation with the aid of succinylcholine (1 mg.kg-1). The control group received saline pretreatment while the study group received pancuronium 1 mg three minutes before succinylcholine. Anaesthesia was maintained with nitrous oxide and oxygen (70:30). A Schiotz tonometer was used to measure intraocular pressure before induction of anaesthesia, one minute after succinylcholine and immediately after intubation. Patients in the control group demonstrated significant elevation of intraocular pressure at one minute after succinylcholine and immediately after intubation, while the study group showed no significant change at the same observation periods. These findings indicate that pretreatment with pancuronium 1 mg three minutes before succinylcholine may be beneficial in patients with high intraocular pressure and penetrating injuries of the eye.     

雷米芬太尼对妇科腹腔镜术中眼内压的影响

目的 观察雷米芬太尼对妇科腹腔镜术中眼内压变化的影响.方法 40例全凭静脉麻醉下行妇科腹腔镜手术的患者随机均分为两组,对照组(Ⅰ组)和雷米芬太尼组(Ⅱ组).所有患者均采用静脉注射咪达唑仑、异丙酚、维库溴铵、芬太尼麻醉诱导,持续输注异丙酚、间断静脉注射维库溴铵麻醉维持.Ⅱ组加用雷米芬太尼.使用笔式眼压计(Tono Pen XL To-nometer)分别于全麻后5 min(T0)、气腹后5 min(T1)、气腹后15 min(T2)、气腹结束前5 min(T3)、气腹结束后5 min(T4)、气腹结束后15 min(T5)测量眼内压(intraecular pressure,IOP),同时观测各时点平均动脉压(mear material pressure,MAP)、心率(heart rat,HR)、呼出终未CO2分压(end tidal CO2 pressure,PETCO2)、气道压(ariway pressure,PAW)的变化.结果 与Ⅰ组相比,Ⅱ组T1、T2、T3时MAP、IOP降低(P<0.05).两组各时点的HR、PETCO2、PAW的无统计学差异.结论 雷米芬太尼能够缓和妇科腹腔镜术中患者眼内压的升高.     

Effect of laryngoscopy and tracheal intubation on pulse pressure and influence of age on this response

The study objective was to measure the change in pulse pressure associated with laryngoscopy and tracheal intubation and to relate these changes to trends in systolic, diastolic and mean blood pressure. The rationale was that the rise in systolic and diastolic blood pressure may be disproportionate and may result in either increase or decrease in pulse pressure. We also looked at the influence of age on this response. This prospective observational study measured the changes in pulse pressure secondary to laryngoscopy and tracheal intubation in eighty adult surgical patients. Two groups of forty patients each were included, young (group A) 18-25 years and middle-aged (group B) 45-55 years. The patients were ASA Class 1 or 2, of either gender and non-hypertensive. Systolic, diastolic, and mean blood pressure, and heart rate were measured preinduction and 1, 2 and 3 minutes after induction. Thereafter they were measured every minute for five minutes after intubation. Pulse pressure was obtained by subtracting the diastolic from the systolic blood pressure. No pulse pressure change occurred in the young group despite of a significant increase in both systolic and diastolic blood pressures. The middle aged group showed an average rise of +18 mm of Hg in pulse pressure (taken at 1 minute post-intubation) compared to the baseline measurement (P<0.0001). These changes in pulse pressure during anaesthesia may indicate an additional pulsatile stress in vulnerable patients in addition to the changes associated with resistance alone and need to be studied further.     

改良中凹位对妇科腹腔镜手术眼压的影响

目的 减少腹腔镜盆腔手术对患者眼压的干扰.方法 将60例腔镜下盆腔手术患者随机分为两组各30例,对照组采用常规头低足高位手术;观察组加用自制体位垫使患者呈改良中凹位.监测全麻后平卧位5 min,摆手术体位后5 min、30 min、1h,手术结束后平卧位5 min眼压.结果 观察组手术全程眼压稳定;对照组于手术体位后5 min眼压开始上升,与组内术前及观察组摆手术位后5 min、30 min、1h比较,差异有统计学意义(P＜0.05,P＜0.01).结论 腹腔镜盆腔手术患者采取改良中凹位可有效降低眼压变化,减轻眼结膜水肿,有利于安全手术.     

Effect of different doses of cisatracurium on intraocular pressure in sedated patients

BACKGROUND AND OBJECTIVE: The aim was to examine the course of intraocular pressure after relaxation with different doses of cisatracurium. METHODS: The investigation was carried out as a prospective, randomized double-blind study in a crossover design in 30 postoperative patients with stable haemodynamic and respiratory function (ASA I and II). To exclude any disrupting factors, patients remained intubated and continuously sedated. Twenty patients received an intubation dose (2 x ED95) of cisatracurium (0.1 mg kg(-1)) compared with atracurium (0.5 mg kg(-1)). In a second series, 10 patients were given an effective dose, ED95 (0.05 mg kg(-1)), and a repeat dose (0.02 mg kg(-1)) of cisatracurium. The intraocular pressure was determined before (T0) as well as 1 (T1), 5 (T5), 10 (T10), 15 (T15), 20 (T20) and 45 (T45) min after bolus administration. RESULTS: Intraocular pressure decreased after an intubation dose of either cisatracurium or atracurium, and reached a minimum after 10 min (6.7 +/- 2.2 and 7.9 +/- 2.1 mmHg, respectively). There was no significant difference between either muscle relaxant (P = 0.27). When lower doses of cisatracurium (0.05 and 0.02 mg kg(-1)) were applied, the intraocular pressure also decreased, albeit to a lesser extent and with a delayed onset (8.4 +/- 1.9 mmHg after 10 min, 9.9 +/- 3.4 mmHg after 15 min). There was no significant difference between dosages (p = 0.44). CONCLUSIONS: Cisatracurium is a useful drug in patients when a decrease of intraocular pressure is wanted and where muscle relaxation is necessary and acceptable.     

Effect of prone position on intraocular pressure during an operation for chiari malformation

目的 探讨俯卧位对Chiari畸形(小脑扁桃体下疝)患者术中眼内压(IOP)的影响,为实施科学的术中体位护理提供参考.方法 对20例Chiari畸形手术患者使用笔式眼压计分别于全身麻醉后5 min(T0)、俯卧位后5 min(T1)、俯卧位后30min(T2)、俯卧位后1 h(T3)、手术结束前俯卧位(T4)、恢复平卧位5 min(T5)、平卧位后30 min(T6)测量IOP,同时观测各时点患者平均动脉压(MAP)、心率(HR)、呼气末二氧化碳分压(PETCO2)变化.结果 不同时点MAP、HR、PET CO2比较,干预主效应差异无统计学意义(均P＞0.05);不同时点IOP比较,干预主效应差异有统计学意义(P＜0.05).T0时IOP均在正常范围,随后IOP逐渐升高至T4时达高峰,T5时逐渐下降,但仍高于T0时点,T6时IOP基本恢复至T0时水平.结论 Chiari畸形手术中随着俯卧位时间的延长患者IOP逐渐升高.护理人员应根据俯卧位对患者IOP的影响规律采取适当的护理干预,医护配合尽量缩短患者围术期俯卧位时间,以减少视力损害的发生,保障手术患者安全.     

血液透析后血浆渗透压改变对眼压的影响

为了探讨维持性血液透析（血透）患者在血透后出现一过性视力下降，眼胀痛等症状是否与血浆渗透压改变有关。方法用Ｓｃｈｉｏｔｚ眼压计在血透前后及治疗中每隔一小时测量一次眼压。检测了前房角，视野及眼压描记及血浆渗透压、血生化等。结果血透后血浆渗透压下降会导致眼压升高。有青光眼解剖特点的眼球，眼压会出现进行性病理升高或诱发青光眼。结论对眼球有青光眼解剖特点的患者在血透时避免大量脱水。血透治疗充分，使治疗后内环境保持相对稳定，可避免眼压的升高。